DETERMINATION OF NUTRITIVE AND ANTI-NUTRITIVE FACTORS OF ADANSONIA DIGITATA LEAFY VEGETABLE COLLECTED IN BIRNIN KEBBI NORTH WEST NIGERIA

Table of Contents

TITLE PAGE 1

CERTIFICATION 2

DEDICATION 3

ACKNOWLEDGEMENTS 4

Table of Contents 6

ABSTRACT 9

CHAPTER ONE 10

INTRODUCTION AND LITERATURE REVIEW 10

1.0 INTRODUCTION 10

1.1 Statement of the Problem 12

1.2 Justification 13

1.3 Objectives of the Study 14

1.4 Limitation of the Study 14

1.5 Significance of the Study 15

LITERATURE REVIEW 16

1.6 Vegetables 16

1.6.1 Classification of Vegetables 17

1.6.2 Leafy vegetables 17

1.6.3 Uses of Vegetables in Foods 18

1.6.4 Importance of Vegetables. 18

1.6.5 Health Benefits of Vegetables 19

1.6.6 Effect of Processing On Green Leafy Vegetables 19

1.6.7 Recommended Daily Intake of Vegetables 20

1.7 Nutrient Composition of Vegetables 20

1.7.1 Moisture Content of Vegetables 21

1.7.2 Carbohydrates. 21

1.7.3 Dietary Fiber 22

1.7.4 Protein Content of Vegetables 23

1.7.5 Fats in Vegetables 24

1.7.6 Ash 25

1.7.7 Minerals 25

1.7.8 Vitamins 28

1.7.9 Anti-nutritional factors 30

1.7.9.1 Phytates 31

1.7.9.2 Oxalates 32

1.7.9.3 Nitrates 33

1.7.9.4 Tannins 33

1.7.9.5 Cyanide 35

1.8 Adansonia Digitata plant and leaves 35

1.8.1 Discovery and Naming 37

1.8.2 Habit and Physical Description 38

1.8.3 Food Uses and Nutrition 39

1.8.4 Nutrients in Adansonia digitat Leafy Vegetables: 39

1.8.5 Antinutrients in Adansonia digitat Leafy Vegetables: 40

CHAPTER TWO: MATERIALS AND METHODS 41

2.1 Materials 41

2.1.1 Procurement of Plant Materials 41

2.1.2 Preparation of vegetable 41

2.1.3 List of Reagents 42

2.1.4 Equipment/Apparatus 43

2.2 Nutritive Analysis. 43

2.2.1 Proximate composition 43

2.2.2 Determination of moisture content 44

2.2.3 Determination of Ash content 44

2.2.4 Determination of Crude lipid 45

2.2.5 Determination of crude protein by Micro kjeldahl Method AOAC (2005) 46

2.2.6 Determination of Crude fiber 48

2.2.7 Determination of Carbohydrates (by difference). 49

2.2.8 Minerals Composition 51

2.2.9 Anti-nutritive Composition 51

2.2.9.2 Determination of oxalate 52

2.2.9.3 Determination of Nitrate 53

2.2.9.4 Determination of Tannins 54

2.2.9.5 Determination of Cyanide 54

CHAPTER THREE: RESULT 56

3.1 Proximate and Ascorbic Acid Composition 56

3.2 Minerals 57

3.3 Anti-nutrient 58

CHAPTER FOUR 59

DISCUSSION, CONCLUSION AND RECOMMENDATIONS. 59

4.1 Discussion 59

4.1.2 Proximate and Ascorbic Acid Composition 59

4.1.3 Mineral composition 62

4.1.4 Anti-nutritive composition 63

4.2 Conclusion 66

4.3 Recommendation 66

REFERENCE 67

Appendix pictures 68

Figure 1 Adansonia digitata 37

List of tables

Table 1Classification of vegetables 17

Table 2 the Recommended Daily Intake of Fruits and Vegetables for Children and Adolescents 20

Table 3 List of Reagents 42

Table 4 Equipment And Apparatus Used In The Study 43

Table 5 Procedure for determination of nitrate 53

Table 6 Procedure for Dtetermination of Tannins 54

Table 7 pprocedure for determination of cyanide 55

Table 8: Proximate and Ascorbic acid composition of Adansonia digitata, leafy vegetable 56

Table 9:  Some Minerals composition of Adansonia digitata, leafy vegetable 57

Table 10: Some Anti nutritive Factors of Adansonia digitata, leafy vegetable 58

ABSTRACT

The study investigated the nutritive and anti-nutritive compositions of Adansonia digitata(baobab) leafy vegetable, the leaves were obtained fresh from birnin kebbi , dried under the shade and pulverized into  powder  using mortar and pestle, Standard methods were used to determine in triplicate the proximate, some minerals,  vitamin c and Anti nutritive composition of A. digitata leaves. For proximate analysis the result showed that the leaves had 9.9% moisture, 8.9% ash, 3.9% fiber, 0.9% lipid and 14% of protein. Minerals values were 77mg Na, 1.2 Ca, 1.4n Mg, 4566mg Ka and 9.1mg phophorus. The leaves contained 321mg of vitamin C. for anti-nutritional content the leaves had traces of oxalate 18.6mg Phytate, 7.3mg nitrate, 0.3mg cyanide, and 132.5mg tannins.

The results suggest that A. digitata leaves are good source of nutrients like carbohydrate, proteins, minerals and vitamin C. The leaves if consume in sufficient amount would contribute greatly to the nutritional requirement for normal growth and adequate protection against diseases arising from malnutrition. 

Interestingly, the anti-nutritional contents of the A. digitata were low excluding Tannins, so the bioavailability of nutrient were high and therefore, its consumption is encouraged as additional source of nutrients to the diet and could be employed in fortification, formulation and supplementation of other food materials. 

CHAPTER ONE

INTRODUCTION AND LITERATURE REVIEW

1.0 INTRODUCTION 

Vegetables include those leafy outgrowths of plants or parts of plants that are used in making soup or eaten with the principal part of the meal (Onimawo & Egbekun, 1998). Green leafy vegetables and fruits occupy an important place among the food crops as these provide adequate amounts of many vitamins and minerals for humans. They are rich source of carotene, ascorbic acid, riboflavin, folic acid and minerals like calcium, iron and phosphorous (Nnam, Onyechi & Madukwe, 2012). They are important protective foods and highly beneficial for the maintenance of good health and prevention of diseases (Kubmarawa, Andenyang & Magomya, 2009).  

According to Socrates, a Greek philosopher, fruits and vegetables are the earliest source of food to mankind (Largen, 1984). Equally Tutare (2000) reported that there are over 200 varieties of vegetables to which majority of Nigerians are not accustomed to.

The major reason for less utilization of fruits and vegetables in Nigeria is due to ignorance of their contribution to adequate nutrition (Kubmarawa et al., 2009; Nnam, 2011). 

 Adansonia digitata leafy Vegetable is used traditionally to make Kuka soup in northern Nigeria including Kebbi State. The tree belongs to the family Bambacaceae, genus Adansonia and specie Adansonia digitata.  The English common names include baobab, deadrat-tree, monkey bread tree (Vertueni et al., 2002). It is also known as the small “pharmacy” or “chemist tree” because of its numerous uses for medicinal purposes.

Adansonia digitata leaves can be eaten as relish and be used for soups in some African countries. The native African populations commonly use the baobab fruit as famine food to prepare decoctions and sauces. Adonsonia digitata is locally called “Kuka” and “Oshe” in Hausa, Kanuri and Yoruba languages in Nigeria. Typically the plant is found in Northern parts of Nigeria in where the leaves are eaten as soup condiments (Venter & Ventes 1996, Pet, 2011). Assagbadjo, Chidere, Kakau and Farson (2012) reported that leaves of baobab are sources of nutrients in Africa where the species occur.  Assagbadjo et al. (2012) also reported that the leaves (fresh and dried) are used in cooking as a type of spinach. Equally, Sena, Jagt, Rivera, Millson, and Glew, (1998) reported that Adansonia digitata leaves were nutritionally superior to the fruit of the tree. In Nigeria, the leaves are locally known as ‘kuka’ and are used to make “kuka soup” (http://en.wikipedia.org/ wiki/baobab). 

The baobab leaves are tender in rainy season and are harvested fresh in the last month of the rainy season, sun dried and either stored as whole leaves or pounded and sieved into a fine powder. In the market the powder is the most common form (Sidebe et al., 1998). Dried green leaves are used throughout the year, mostly in soups served with the staple dish of millet (Delisle et al., 1997). Nnam & Nwofor (2001) reported that baobab leaves, fruits and seeds are used as articles of food in the northern states of Nigeria where it grows extensively but are not consumed in the southern states.

Adansonia Digitata leafy vegetable contains anti-nutritional factors that can affect the availability of nutrients to the human body. These anti-nutritional factors interfere with metabolic processes and reduce the bioavailability of nutrients from plants or plant products used as human foods (Abara, 2003; Agbaire and Emoyan, 2012). 

Some of the reported anti-nutritional factors in Adansonia digitata are saponins, tannins, phytic acid, oxalates, protease inhibitors, Alkaloids and nitrates. Of these work oxalates, phytates, Tannin and nitrates are of more major concern.

1.1 Statement of the Problem

Malnutrition has been a major problem in northern Nigeria including Kebbi State for a long time. This is mainly protein energy malnutrition which leads to kwashiorkor, but there is also public health concern of high prevalence of some micronutrient deficiency conditions. According to KENRIK (2004), small children and women in child bearing age are worst hit by protein, calcium, iron, vitamin A, and vitamin C malnutrition. Children below 5 years suffer iron deficiency anemia. 

According to World Health Organization, in developing countries, every second pregnant woman and about 40% of preschool children are estimated to be anemic. In many developing countries, iron deficiency is aggravated by worm infections, malaria and other infectious diseases like tuberculosis. The major health consequences include poor pregnancy outcome, impaired physical and cognitive development, and increased risk of morbidity in children and reduced work productivity in adults. Anemia also contributes to 20% of all maternal deaths.  Adansonia Digitata vegetable has been documented as a nutritious vegetable and can help in the fight against malnutrition. 

Anti-nutrients are generally present in foods, especially vegetables. Most of them reduce the bioavailability of nutrients. Adansonia digtata leaves was documented to contain various anti-nutrients including tannins, phytates, oxalates, cyanide and nitrates. Tannins bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids, reducing their bioavailability in the body. Phytate is not digestible to humans; it also chelates and makes unabsorbable certain minerals such as zinc, iron, calcium and magnesium. Oxalates bind calcium making it unavailable for absorption. High oxalate levels may also interfere with carbohydrate metabolism. Nitrates in Adansonia Digitata leaves are also of concern since it is hypothesized that nitrates may be chemically changed in the Digestive tract into poisonous/carcinogenic nitrosamines. High level of nitrates in vegetables when ingested can be converted to nitrite which can lead to cancer and metheamoglobinemia or blue-baby disease (Gupta et al., 2000). 

There are many reports on the nutritive value of Adansonia Digitata (baobab) fruits, it has been reported that African baobab fruit contains 50% more calcium than spinach, is high in antioxidants, and has three times the vitamin C of an orange. (The Tree of Life 2015). Yet there are very few documented studies on the nutrient, anti-nutrient and phytochemical composition of Adansonia Digitata leafy vegetable. 

Plants generally contain chemical compounds (such as saponins, tannins, oxalates, phytates, trypsin inhibitors and nitrates) which are known as secondary metabolites and are biologically active (Soetan and Oyewole, 2009). 

Some of the reported anti-nutritional factors in Adansonia digitata are phenolics, saponins, tannins, phytic acid, oxalates, protease inhibitors, nitrates and polyphenols. Of these, oxalates, phytates, cyanide and nitrates are of more concern. 

1.2 Justification 

Leafy vegetables play a vital role in human wellbeing. It has been established that greens contribute significantly to the daily dietary requirements of calcium and iron among children. Dark green vegetables have been suggested to be significant sources of vitamin A and other nutrients in Africa (Faber et al. 2007; Oiye et al. 2009; Tchum et al., 2009). There is need for diversification of foods and diet to ensure good health and prosperity. In Nigeria and even worldwide, many people are conscious about their health status. This propels a need for in-depth studies and improvement of nutritious foods so as to improve and support the people‘s health status. Adansonia digitata leaves and other African indigenous vegetables become important sources of nutrients to achieve this goal. 

Leafy vegetables including Adansonia Digitata leaves serve as the main source of mineral nutrients, particularly in resource-poor households in low-income countries, since intake of dietary supplements is low (Wambugu and Muthamia, 2009).

1.3 Objectives of the Study 

1.3.1 Broad objective 

To determine nutritive, and anti-nutritive factors contents of Adansonia Digitata leafy vegetable.

1.3.2 Specific objectives 

To determine the Carbohydrate, proteins, lipid, Vitamin C, and minerals contents of Adansonia Digitata leafy vegetable. 

To determine the level of oxalates, phytates, tannins, cyanide and nitrates content of Adansonia Digitata leafy vegetable.

1.4 Limitation of the Study

The research work is limited to determine the nutritive and anti-nutritive factors in Adansonia Digitata (Baobab) leafy vegetable collected in Birnin Kebbi, northern Nigeria, likewise the result will only be of great significance to the named metropolis.

1.5 Significance of the Study

It would increase the consumption of Baobab leafy vegetables in many parts of the country where the vegetables are less known and consumed even when they are available in large quantities in the places. 

The result would also provide valuable information for use in compiling the food composition table on Nigerian foods.

The result will help make people heat, sprout and soak their vegetables and other legumes so as to inactivate the anti-nutritional factors present in them before making them ready for consumption. 

LITERATURE REVIEW

1.6 Vegetables

The term vegetable usually refer to the fresh edible portion of an herbaceous plant – root, stem, leaves, flower or fruits (Encarta, 2009). Onimawo & Egbekun (1998) described vegetables as leafy outgrowths of plants used as food and included those plants and parts of plants used in making soups or served as integral part of the main meal. The use of leafy vegetables is part of Africa’s cultural heritage and vegetables play important roles in the food culture of African households (Ene-Obong 2008). Tutari (2000) reported that Nigeria is endowed with a variety of vegetables. Different ethnic groups consume various types of vegetables for different reasons. Vegetables are the cheapest and most available sources of important proteins, amino acids, vitamins and minerals (Okaka, 2000).

Vegetables in the diet have many positive effects upon health because of their constituents. Some vegetables have medicinal prosperities and can be used for the sick and convalescences (Kubmarawa, 2009; Nnam et al., 2012).

Vegetables are naturally low in fat and calories. None have cholesterol; many are good sources of fiber, minerals and vitamins (Lloveindia, 2004). Vegetables equally contain carbohydrates and protein.

Until most recently a group of chemicals known as phytochemicals were discovered. They are found only in plant based food in very small amount (Nnam, 2011).

1.6.1 Classification of Vegetables

Vegetables can be categorized according to their type and taste

Table 1; Classification of vegetables

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TYPE’S                                                                                                      EXAMPLES

_______________________________________________________________________

Bulb Vegetables                                        Onions, Garlic And Shallots

fruit vegetables                     avocadoes, cucumbers, tomatoes, pepper and egg plan

Inflorescent Vegetables                                Broccolis And Artichokes

Leafy vegetables                              bitter leaf, lettuce, spinach and cabbage.

root vegetables                                        carrots, beets, radishes and turnips

Stalk vegetables                                          asparagus, bamboo and celery.

Tuber vegetables                                    cassava, yam, sweet potato and taro

_______________________________________________________________

Source: Iloveindia, 2004.

1.6.2 Leafy vegetables

Leafy vegetables are many, ranging from leaves of annuals and shrubs to leaves of trees. Leaf vegetables are also called potherbs, greens, vegetable greens, leafy greens or salad greens, they are plant leaves eaten as vegetables sometimes accompanied by the tender petioles and shoot. Although they come from a wide variety of plants most share a great deal with other vegetables in nutrition and cooking methods. Nearly one thousand species of plants with edible leaves are known. Leafy vegetables most often come from short lived herbaceous plants such as lettuce and spinach. Woody plants whose leaves can be eaten as leaf vegetables include Adansonia, Aralia, Casia Tora, and Moringa.  The leaves of many fodder crops are also edible by humans, but usually only eaten under famine conditions example alfalfa, clover and most grasses. They are generally good sources of nutrients (Sundarrayanan et al., 2011). They contain lots of carbohydrates, and are rich in carotenoids and vitamin c. they are also good sources of fiber, folate and supply varying amounts of iron and calcium. 

leafy vegetables contain many typical plant nutrients but since they are photosynthetic tissues their vitamin k levels in relation to those of other fruits and vegetables as well as other foods is particularly notable (Pamplona-roger, 2005).

1.6.3 Uses of Vegetables in Foods

 Vegetables are used in foods depending on the purposes to be achieved. they may be used as major or minor ingredients in soups, sauces, stews, pottage, porridge and salads to enhance the flavor of foods, garnish prepared dishes so as to enhance eye appeal, serve as fillings for sandwiches, pies and indian egg rolls. They can serve as a critical part of the ingredients in the preparation of certain dishes such as vegetable soup, vegetable pottage, vegetable parcels and salads (enwere, 1998).

1.6.4 Importance of Vegetables.

Vegetables provide essential vitamins, minerals, fiber and other substances that are important to good health. Eating plenty of vegetables everyday can help reduce risk of heart disease, high blood pressure, type ii diabetes and certain cancers. Vegetables have many important phytochemicals that help to protect health. Phytochemicals are usually related to color. Vegetables of different colors green, yellow-orange, red, blue-purple, and white contain their own combination of phytochemicals and nutrients that work together to promote good health. Vegetables are low in calories and fat. They are high in fiber and are filling thus they can help to control weight.

Vegetables are natural source of energy; they give the body many nutrients needed to keep going. Busy lives require food that is nutritious, energizing, and easy to eat on-the-go, like fresh fruits and vegetables (national cancer institute, 2009).

1.6.5 Health Benefits of Vegetables

Recent researches show that most people will benefit from increasing their fruit and vegetable intake (University Of Warwick, 2012). 

Life time habit of eating adequate amount of fruits and vegetables every day can help prevent coronary heart disease, constipation, and some forms of cancer, overweight and obesity. It can also reduce blood pressure and blood cholesterol levels and improve control of diabetes. 

(Www.nutrition.org.uk/healthy living/.).

1.6.6 Effect of Processing On Green Leafy Vegetables

Processing of vegetables involves cleaning, sorting, grinding pounding, trimming, blanching, canning, storage, freezing and drying (Enwere, 1998). Squeeze washing and cutting are popular procedures among Nigerians in preparation of certain green leafy vegetables. The choice of processing method depends on the product desired and storage facilities available. It may have beneficial or harmful effects on different properties of the vegetable. According to Mepba, Eboh and Banigo (2007) leafy vegetables are highly perishable food items and require special processing treatments to prevent post-harvest losses. Mepba et al. (2007) further reported that in Nigeria, leafy vegetables are preserved by sun-drying and used like freshly harvested vegetables in soups. They can also be cooked or dried, depending on the mode of utilization (Shittu & Ogunmoyela, 2001). Moshe, Pace, Adeyeye, Laswai And Mtebe (1997) reported that-traditional sun drying of cowpea leaves resulted in severe losses of pro vitamin a. shade drying and storing in airtight containers produced better results (Mosha et al., 1997). boiling and then discarding the water used for boiling vegetables provides a good means of reducing the oxalate content of some leafy vegetables and consequently the associated food safety problems (Ogbadoyi et al., 2006).

1.6.7 Recommended Daily Intake of Vegetables

Table 2: the Recommended Daily Intake of Fruits and Vegetables for Children and Adolescents

 

Age (Yrs.) Fruits Serve                             Vegetables Serves

________________________________________________________________

4-7                                            1-2                                         2-4

8-11                                         1-2                                           3-5

12-18                                        3-4                                          4-9

______________________________________________________________

Source the Australian Guide to Healthy Eating, (2012).

1.7 Nutrient Composition of Vegetables

Nutrients are the essential substances obtained from food    (www.nutrition.org.uk/healthyliving.). They are what the body needs to perform its functions properly. The classes of nutrients are carbohydrates, proteins, fats, vitamins, minerals and water. Water which helps to assimilate nutrients and fiber which helps with regular elimination of toxins and wastes are very important nutrient facilitators in foods (www.healthy-eating.and.nutrition.co.). 

Fruits and vegetables are naturally good. They contain vitamins, minerals and other compounds like antioxidants and phytochemicals. These substances help to protect the body against diseases. Some vegetables contain some anti-nutrients and toxicants (Bokanga, 1994).

1.7.1 Moisture Content of Vegetables

Vegetables naturally have high levels of water. This is the reason why they are generally fat free and low in calories (www.organicfacts.net/health). Both weight and health are controlled with diets rich in vegetables. Fresh green leafy vegetables are high in moisture. The level in individual sample depends on several factors such as age, agronomic practices prevailing during cultivation and freshness (Oguntona, 1998). The moisture in green leafy vegetables ranges from 72% in cassava leaves to 93% in water leaf (Onimawo & Egbekun, 1998). Proper moisture content is essential for maintaining fresh healthy foods (www.ehow,> ehow> healthy living). The moisture content of the dried vegetables also varies. Generally, vegetables are traditionally sun- dried. Eka and Osagie (1998) reported that vegetables continue to lose moisture while in storage or display depending on the local environmental condition. Vegetables with high moisture content are called high water content.

Foods with 80-95% of their total composition being water. The more vegetables consumed the more water intake that flushes out waste products from the body (www.healthy-eating.and. nutrition. co).

1.7.2 Carbohydrates.

Carbohydrates are present in foods in form of sugars, starches and fiber. Vegetables are important sources of both digestible and indigestible carbohydrates. The digestible carbohydrates are present largely in the form of sugars and starches (Eka & Osagie, 1998).  The indigestible carbohydrates are in the form of fiber. Carbohydrates are eventually metabolized by the body into blood glucose. All cells of the body utilize glucose as the primary energy source, particularly in the brain, for which glucose provides the only source of fuel. Excess carbohydrates are converted into triglycerides forb storage in adipose or fat cells, leading to weight gain. Incomplete carbohydrate metabolism leads to accumulations of sugar in the blood a condition known as hyperglycemia, a manifestation of diabetes.

Starch also known as complex carbohydrate or polysaccharide, is present in foods such as cereals, whole grains, rice, pasta, potatoes, peas, corn and legumes. Sugar is found naturally in many foods.

They have simpler chemical structure than starch. Food sources of natural sugar include fruit, vegetables, milk and yoghurt. Low sugar vegetables include tender green leafy vegetables, spinach, lettuce etc. foods containing natural sugars are generally very nutritious, providing many vitamins, minerals, phytochemicals (natural plant chemicals) and antioxidants. These foods also tend to be good sources of fiber, such as that found in fruits, vegetables and whole grains. However, foods high in added sugars are often referred to as sources of "empty calories," meaning they add calories to the diet but provide little benefit in terms of vitamins, minerals or fiber. Most plant foods are good sources of fiber.

1.7.3 Dietary Fiber

Dietary fiber sometimes referred to as roughage or bulk encompasses all substances and compounds that pass through the intestine undigested. Fiber is found only in foods of plant origin. Fiber is divided into two general categories _soluble fiber which are compounds that dissolve in water and insoluble fiber which are those that bind to water. Vegetables including green leaves are significant sources of both soluble and insoluble dietary fiber (Egbuna 2000). Available evidence suggests that the soluble components represents 25% or less of the fiber present in most natural food stuffs while the insoluble fraction accounts for 75% of the fiber content (Onimawo & Egbekun, 1998). Soluble fiber promotes healthy cholesterol and blood sugar levels. Dietary fiber increases the weight and size of stool and softens it. In the presence of adequate amount of fluid insoluble fiber makes stool larger, softer and easier to pass thereby decreasing the chance of constipation (Cumming, 1981). a high-fiber diet may lower the risk of specific disorders, such as hemorrhoids, irritable bowel syndrome and the development of small pouches in the colon (diverticular disease). While most food sources contain varying amount of both soluble and insoluble fiber, some foods are especially rich in one type. soluble fiber found in beans, oats, flaxseed and oat bran may help lower total blood cholesterol levels by lowering low-density lipoprotein, or "bad," cholesterol levels (Onimawo & Egbekun, 1998).

Soluble fiber can slow the absorption of sugar, which for people with diabetes can help improve blood sugar levels. a high-fiber diet may also reduce the risk of developing type 11 diabetes (www.healthy eating. sfgate.com>). 

High-fiber foods generally require more chewing time, which gives the body time to register when the body is no longer hungry, cutting down overeating (cumming, 1980). Also, a high-fiber diet tends to make a meal feel larger and linger longer, so the body stays full for a greater amount of time. High fiber diets also tend to be less "energy dense," which means they have fewer calories for the same volume of food.

1.7.4 Protein Content of Vegetables

Every cell and tissue in the body contains protein. Different proteins work as enzymes, hormones, neurotransmitters, antibodies and specialized proteins such as heamoglobins and others (Bean, 2000).proteins are constantly repairing body tissues to keep it healthy. They are made up of amino acids.

There are two types of amino acids- essential and non- essential. The eight essential amino acids cannot be made in sufficient amounts in the body and most therefore be supplied in the food. The twelve non-essential amino acids can be made from other amino acids in the diet. Foods containing animal protein such as meat, milk and eggs, contain ample amounts of all essential amino acids.

Vegetable protein sources have one or more of the essential amino acids missing or have less than the adequate amounts (http://www.eufic, org). These foods however can be combined in a diet that supplies the required amounts (who, 1985). Crude protein content of green leafy vegetables ranges from 1.5% to 1.7 %.( who, 1985; Aletor & Adeogun 1995). Some vegetables such as legumes are great sources of plant proteins. Proteins combine well with green leafy vegetables and non-starchy vegetables (www.marilu.com/.../ food combining...)

1.7.5 Fats in Vegetables

Green leafy vegetables are known to be poor sources of fat (en.wikipedia.org/wiki/leaf. veg.).  Fat represents the lowest among the proximate components. Oguntana (1998) reported that the ether extract scarcely exceeds 1.0% in fresh leafy vegetables. The values from dry samples range from 1.0- 3.0%. However, dark green leafy vegetables contain omega 3 fatty acids. Omega 3 fatty acids are called essential fatty acids because the body cannot manufacture them from other nutrients. It must be obtained from the diet. Omega 3 fatty acids come in three varieties namely alpha linoleic acid (ala), decosol hexanoic acid (dha) and eicosoi pentonoic acid (epa).they give important health benefits to the body. They may help to prevent breast and colon cancer, high blood pressure and can reduce the risk of suffering a stroke among other benefits. ala is found primarily in dark green vegetables, flax seeds, hemp seeds, walnuts and a variety of vegetable oils. epa is found primarily in cold water fish like salmon, cold mackerel and tuna as well as fresh seaweed. dha are found in the same foods that epa is found. Dark green vegetables are among the highest sources of ala (www.young women health org>). Most humans can convert ala found in plant foods to dha and epa in the body to provide all its health benefits. Theoretically eating foods containing ala or dark green vegetables can produce enough dha and epa but the controversy is that some people cannot efficiently convert ala to dha and epa. It is wise and safe to eat a variety of foods that are naturally rich in ala, epa and dha rather than to rely on a supplement that contains just one or more of this omega 3 fatty acids as isolated nutrients. Researches confirmed that the body needs a little dietary fat to absorb some of the vitamins found in dark green leafy vegetables

 (www.young women health org>).

1.7.6 Ash

The ash content is a measure of the total amount of mineral present within a food whereas the mineral content is a measure of the specific inorganic components present within a food (www.soil and health.org/06clipfile/rc). 

The percentage of ash and each of the constituents of ash of any given species of plants are known to vary widely. They vary with the variety and with the age of the plant and the environmental condition under which it was grown (Onimawo & Egbekun, 1998). Such variations are of considerable significance to animals and man since these creatures depends on plants for most of their mineral matter.

1.7.7 Minerals

Minerals are elements that originate in the soil and cannot be created by living things such as plants and animals   (www.health.alternatives.com/minerals). They are also known as micronutrient.

They do not provide the body with energy but they help the body to carry out the metabolic processes. Plants, animals and humans need minerals in order to be healthy. There are two kinds of minerals: macro minerals and trace minerals. The macro minerals include calcium phosphorous, magnesium, chlorine, sodium and potassium. The trace minerals are required in trace amounts and they play catalytic functions in the body. They include copper, iron, cobalt, iodine, molybdenum, selenium and manganese.

Plants absorb minerals from the soil; animals get their minerals from the plants or other animals they eat. Most of the minerals in the human diet come directly from plants such as fruits and vegetables or indirectly from animal sources. Minerals may also be present in drinking water depending on the type of water and sources (www.heaalth.alternatives.com/mineral…). Minerals from plant sources may also vary from place to place because the mineral content of the soil varies according to the location in which the plant was grown. Vegetables are important sources of mineral elements calcium, phosphorus and iron (Onimawo & Egbekun, 1998).

 Green leafy vegetables are, particularly rich in iron and calcium but low in sodium (Egbuna, 2000). Some vegetables like Swiss chord and spinach that are high in oxalic acids are often low in iron and calcium because the oxalic acid tends to chelate the calcium and iron in these vegetables. (www.heaalth.alternatives.com/mineral…). Dietitian’s advice that one serving of green leafy vegetables each day will considerably lower the risk of diabetes (www.organicfacts.net/health-benefits). Some minerals are essential to health while others can be toxic example lead, mercury, cadmium and aluminum. While all minerals play key roles in the body processes manganese, copper and zinc are particularly important in energy metabolism.

Calcium, phosphorus, iron, magnesium, iodine and selenium are also important in carbohydrate metabolism.

Magnesium

Magnesium is required in energy production. It catalyzes conversion of ATP to ADP in carbohydrate metabolism. Intake of magnesium supplement helps the diabetic patient to improve insulin and glucose level (www.bodybuildingtipsguide.com.) studies have shown that 80% of the people suffering from diabetes have magnesium deficiency. thus, intake of magnesium reduces the duration, intensity and frequency of urination (www.bodybuildingtipsguide.com). its other functions include making new cells, activating b vitamins, relaxing nerves and muscles and blood clotting. Insulin secretion and function also requires magnesium. It also assists in the absorption of calcium, vitamin c and potassium. Deficiency of magnesium results in fatigue, nervousness, heart problem, weakness and cramps. Rich vegetable sources of magnesium include spirulina, okra, green vegetables, Amaranthus leaves and legumes. Its recommended daily intake for adult is 310 to 420mg/day; children 130 to 240mg/day (www.magnesium. org).

Sodium

Sodium is the chief cation of the extracellular fluid. About 50'/' of body sodium is present in the bones, the extracellular fluid and the remaining (10%) in the soft tissues. in association with chloride and bicarbonate, sodium regulates the body's acid base balance. Sodium is required for the maintenance of osmotic pressure and fluid balance. lt is necessary for the normal muscle irritability and cell permeability.  Sodium is involved in the intestinal absorption of glucose, galactose and amino acids. lt is necessary for initiating and maintaining heartbeat. For normal individuals, the requirement of sodium is about 5-10 g/day which is mainly consumed as NaCl. For persons with a family history of hypertension, the daily NaCl intake should be less than 5 g. For patients of hypertension, around l g/day is recommended.

Potassium

Potassium is the principal intracellular cation. I t is equally important in the extracellular fluid

For specific functions. Biochemical functions. Potassium maintains intracellular osmotic Pressure, lt is required for the regulation of acid base balance and water balance in the cells. The enzyme pyruvate kinase (of glycolysis) is dependent on K+ for optimal activity. 4Potassiumis required for the transmission of nerve impulse. Adequate intracellular concentration of K + is necessary for proper biosynthesis of proteins by ribosomes.  Extracellular   K+ influences cardiac muscle activity. Dietary requirements about 3-4 g/day.

Calcium

Calcium is the most abundant mineral in the human body .the recommended daily intake of calcium for adults is 1000mg/day; children 800 - 1300mg/day. Good sources of calcium include dark green vegetables, okra, beans, Brussels and milk. Potassium acts as catalyst in energy metabolism.

Phosphorus

Phosphorus aid in metabolic reactions (as component of DNA and RNA, ADP, ATP and TPP). It is widely distributed in both plant and animal foods. Iodine aids in regulating basal metabolism (as a component of thyroxin and tri-iodothyroninine. its sources include iodized salt, salt water fish. sodium aids in the absorption of glucose.

1.7.8 Vitamins

Vitamins are organic compounds that are necessary for normal growth and maintenance of life. The body cannot synthesize vitamins; they must be taken in food and food supplements. Adequate intake is necessary for normal functioning of the body. Thirteen essential vitamins have been isolated and these are divided into 2 categories; water soluble vitamin and fat soluble vitamins. The water soluble vitamins include vitamin c and the b group of vitamins. These water soluble vitamins are not stored by the body and can be readily depleted. The fat soluble vitamins include vitamin a, d, e and k. they can be stored in the body (www.livestrong.com). Vitamin d sometimes is not regarded as essential because it can be synthesized in the body by the action of ultra violet rays of sun on dehydrocholcalciferol in the skin of humans. carnitine a vitamin like compound very indispensable for survival and health are not strictly "essential" because the human body has some capacity to produce them from other compounds (www.nutrition. org. uk/healthy living).

Specific conditions are known to arise as a consequence of a dietary deficiency of one or more of the vitamins. These conditions can be avoided if meals are well planned and carefully prepared (Eneobong 2001; Nnam 2010). 

Dietitian’s advice that the practice of warming or heating vegetable soups every morning should be discouraged as many vitamins are lost in the process. Excess of some vitamins especially the fat soluble vitamins could be dangerous to health.

In general vegetables are good sources of vitamins. The factors that influence the amount of vitamins in green leafy vegetables are cultivars, maturity and light (Egbuna, 2000). Green leafy vegetables are the richest source of thiamin and riboflavin, ascorbic acid and beta carotene (pro-vitamin a).

Oguntona, (1998) And Egbuna (2000) reported that niacin and folate are found in reasonable amount in green leafy vegetables. Other sources of vitamins include meat, eggs poultry, fish, and cereals.

Vitamins involved in energy metabolism

All vitamins play key roles in the body processes, vitamin B12 and pantothenic acid are particularly important in energy metabolism. Niacin, thiamin, riboflavin, biotin, are also important in carbohydrate metabolism. When vitamin b12 is taken in the body, it is broken down into several compounds including 5 deoxy adenosylcobalamin. This compound is used by an enzyme to catalyze important biochemical process that the body uses in the metabolism of energy from protein and fat.

Pantothenic acid also called vitamin b5 is used by the body to form an enzyme called coenzyme.

Coenzyme a is used in biochemical reactions that result in the body’s production of energy from carbohydrates, fats and proteins.

Vitamin c

Vitamin c also known as ascorbic acid, is a water soluble antioxidant that scavenges free radicals and reactive oxygen molecules produced during metabolic pathways of detoxification (Proteggente, Pannak, And Wagner & Evans 2002). Vitamin c as an antioxidant protects the DNA of the cells from damages caused by free radicals and mutagens .Gaby And Singh (1991) reported that vitamin c prevents harmful genetic alterations within cells and protects lymphocytes from mutation to the chromosomes. another way in which vitamin c protects the body is by preventing the development of nitrosamines, the cancer causing chemical that stem from the nitrates contained in foods (Gaby &Singh, 1991). Vitamin c is an excellent source of electrons to free radicals such as hydroxyl and superoxide radicals; being water soluble it works both in and outside the cells to stop their reactivity by donating electrons to them (Bendich, 1990). Vitamin c works with glutathione peroxidase (aMajor free radical fighting enzyme) to revitalize vitamin e, a fat soluble antioxidant. Vitamin c being water soluble cannot be stored in the body it is important to obtain it regularly from its major sources- fruits and vegetables. The important sources include citrus fruits, green pepper, broccoli, green leafy vegetables, kiwi, strawberries, raw cabbage and potatoes (Kendall, 2000).

Anti-nutritional factors

Vegetables contain anti-nutritional factors that can affect the availability of nutrients to the human body. These anti-nutritional factors interfere with metabolic processes and reduce the bioavailability of nutrients from plants or plant products used as human foods (Abara, 2003; Agbaire and Emoyan, 2012). Plants generally contain chemical compounds (such as saponins, tannins, oxalates, phytates, trypsin inhibitors and nitrates) which are known as secondary metabolites and are biologically active (Soetan and Oyewole, 2009). 

Some of the reported anti-nutritional factors in adansonia digitata are saponins, tannins, phytic acid, oxalates, hydrogen cyanide and nitrates. 

In this work the anti-nutrients under study are oxalates, phytates, Tannins, hydrogen Cyanide and nitrates.

1.7.9.1 Phytate 

Phytic acid, also known as inositol hexasphosphate or phytate when in the salt form, is the storage form of phosphate in many plant tissues. It is not digested by humans and is therefore not a dietary source of inisitol or phosphate. They bind iron, zinc, calcium and magnessium. In presence Ca2+ and Mg2+, it forms insoluble complexes which are not readily absorbed by the gastrointestinal tract (Akande et al., 2010; Agbaire and Emoyan, 2012). On germination of grains, the phytate reduces due to enzymatic breakdown of phytate that improves iron availability. 

According to Oke (1969) a phytate diet of 1- 6% over a long period of time decreases the bioavailability of mineral elements in mono gastric animals. Phytic acid acts as a strong chelator forming protein and mineral-phytic acid complexes thereby decreasing protein and mineral bioavailability (Erdman, 1979). Phytate is associated with nutritional diseases such as rickets and osteomalacia in children and adult, respectively. 

Phytic acid as a phytochemical, however, has several beneficial properties including; anti-cancerogenous, antioxidant anti-inflammatory, lowering cholesterol level, blood glucose lowering. (Watzl and Leitzmann, 1999). Phytic acid is used as an acidulant for pH adjustment in foods and beverages as it does not affect the original taste; it also has potential to prevent color degradation in food or beverage including anthocyanin. Phytic acid is one of the most potent natural iron chelator and has strong bacteriostatic and antioxidant action (Graf and Eaton, 1990; Graf et al, 1987).  

1.7.9.2 Oxalates 

Excessive amounts of oxalic acid may reduce the availability of certain minerals in the body, most notably calcium. This could be a concern especially if calcium intake levels are low to begin with, or if foods high in oxalic acid are consumed on a regular basis over long periods of time. Oxalates occur in many plants where it is synthesized via incomplete oxidation of carbohydrates. 

In the body, oxalic acid combines with divalent metallic cations such as calcium (Ca2+) and iron (II) (Fe2+) to form crystals of the corresponding oxalates which are then excreted in urine as minute crystals. These oxalates are known to form insoluble calcium oxalate with calcium thereby preventing the absorption and utilization of calcium by the body hence causing diseases such as rickets and osteomalacia (Ladeji et al., 2004; Agbaire, 2012). 

Accumulation of this insoluble compound in the renal glomeruli leads to the formation of renal calculi and kidney damages (Nwachukwu and Obi, 2007; Maikai and Obagaiye, 2007). Accumulation of oxalates appear to be related nitrate assimilation and cation-anion imbalance (Fasett, 1973) 

Metabolism and absorption of oxalates 

Oxalate combine with calcium to form calcium oxalate in the lumen; making calcium unavailable for absorption. The calcium oxalate is later excreted in feaces. 

Free or soluble oxalate is absorbed by passive diffusion in the colon in humans (Hughes et al., 1992; Modigliani et al., 1978). Other studies also suggest that the small intestine is the major absorption site rather than the colon (Prenen et al., 1984). 

It has been estimated that about 2-5% of the total oxalates administered is absorbed in the body; while its absorption is higher at lower doses (Finch, et al., 1981). 

Toxic effects of oxalates 

Minimum doses that can lead to death are 4-5 g of oxalate (Fasset, 1973); whereas other studies show that 10-15 g is the usual dose that causes fatalities. Ingestion of oxalic acid results in corrosion of the mouth and the gastrointestinal tract; gastric hemorrhage; renal failure and haematuria (Concon, 1988). High oxalate levels may interfere with carbohydrate metabolism. 

1.7.9.3 Nitrates 

Nitrates in adansonia digitata leaves are a concern since it is hypothesized that nitrates may be chemically changed in the digestive tract into poisonous/carcinogenic nitrosamines. High level of nitrates in vegetables when ingested can be converted to nitrite which can lead to cancer and metheamoglobinemia or blue-baby disease (Gupta et al., 2000; Macrae, et al., 1997; Oguchi et al., 1996; Takebe and Yoneyame, 1997). Boiling the leaves like spinach or chard 5-10 minutes, then discarding the water alleviates both oxalate and nitrate problems (Ogbadoyi et al., 2006). 

1.7.9.4 Tannins 

Tannins are condensed bitter plant polyphenolic compounds which are present in high amounts in seed coats of most legumes, and certain fruits and vegetables including amaranth. Tannins may precipitate proteins from aqueous solution by inhibiting digestive enzymes (Soetan and Oyewole, 2009) and have been found to interfere with digestion by displaying anti-trypsin and anti-amylase activity. Tannins chelate iron and zinc irreversibly and interfere with their absorption. 

Major classes/polymer of tannins includes the hydrolysable tannins and non-hydrolysable or condensed tannins; which are both found in plants. Tannins are distributed throughout the plant kingdom and are common in both gymnosperms and angiosperms. The most abundant polyphenols are the condensed tannins, found in virtually all families of plants, and compromising up to 50% of the dry weight of leaves.

 Tannins have traditionally been considered anti-nutritional but it is now known that their beneficial or anti-nutritional characteristics depend on their chemical structure and dosage. Condensed tannins can inhibit digestion by binding to plant proteins, making them more difficult to digest. They also interfere with protein absorption and digestive enzymes. Other studies show that tannin, also known as proanthocyanidins, possess various properties such as antioxidants, anti-aging, anti-apoptotic, anti-inflammatory, anti-carcinogenic as well as anti-atherosclerosis and cardiovascular protection. 

Uses of tannins 

They are an important ingredient in the process of tanning leather. Mimosa, oak and other have traditionally been the primary source of tannery tannin, though inorganic tannin agents are also in use today and accounts for 90% of the world’s leather production (Marion and Thomson 2006). 

Tannins produce different colours with ferric chloride according to the type of tannin. Iron gall ink is produced by treating a solution of tannins with iron (II) sulphate.  It is a component in a certain type of industrial adhesive developed jointly by the Tanzania Industrial Research and Development Organization and Forintek Labs Canada (Bisanda et al. 2003). Pinus radiata tannins have also been investigated for the production of wood adhesives (Li, and Maplesden, 1998). Condensed tannins and hydrolysable tannins appear to be able to substitute synthetic phenols in phenol-formaldehyde resins for wood particleboard. 

Medical uses and potential 

Tannins may be effective in protecting the kidneys. When incubated with red grape juice and red wines with a high content of condensed tannins, the poliovirus, herpes simplex virus, and various enteric viruses are inactivated. Tannins have shown potential anti-viral, antibacterial and anti-parasitic effects.

1.7.9.5 Cyanide

Cyanide are group of compound that contain cyano group it’s highly toxic, cyanide is found in many plant, in plant cyanide is bound to sugar molecule in the form of cyanogenic glycoside and it defends the plant against herbivores.

Cyanide prevent tissue utilization of oxygen by inhibiting cellular respiratory enzymes and cytochrome oxidase. Inhalation or ingestion of cyanide can cause reactions which can lead to death.

1.8 Adansonia Digitata plant and leaves

Adansonia digitata belongs to the family Bambacaceae, genus Adansonia and specie Adansonia digitata Linl. It is a deciduous majestic tree up to 25m high, Audu (1989) reported that it may live for hundreds of years. The form of the trunk varies. In young trees it is conical, in mature trees it may be cylindrical, bottle shaped or tapering with branching near the base (Yusha, Hamza, & Abdullahi, 2010). 

The leaves, the stem bark and soult pulp are all very useful foodstuffs. Adonsonia digitata is the most widespread of the Adonsonia species on the African continent found in hot dry savannah of sub-saharan African (Vertueni, Broccoli & Buzzona, 2002). The English common names include baobab, deadrat-tree, monkey bread tree (Vertueni et al., 2002). It is also known as the small “pharmacy” or “chemist tree” because of its numerous uses for medicinal purposes.

The specific epithet digitata refers to the fingers of a hand which the five leaflets (typically) in each cluster bring to mind. All parts of the plant have medicinal properties (Vertuani et al., 2002). The leaves can be eaten as relish and be used for soups in some African countries. The native African populations commonly use the baobab fruit as famine food to prepare decoctions and sauces. Adonsonia digitata is locally called “Kuka” and “Oshe” in Hausa, Kanuri and Yoruba languages in Nigeria. Typically the plant is found in Northern parts of Nigeria, especially Adamawa, Borno, and Yobe states where the leaves are eaten as soup condiments (Venter & Ventes 1996, Pet, 2011).

Assagbadjo, Chidere, Kakau and Farson (2012) reported that leaves of baobab are sources of nutrients in Africa where the species occur. Assagbadjo et al. (2012) also reported that the leaves (fresh and dried) are used in cooking as a type of spinach and can also be used as foragie. Equally, Sena, Jagt, Rivera, Millson, and Glew, (1998) reported that Adansonia digitata leaves were nutritionally superior to the fruit of the tree. In Nigeria, the leaves are locally known as ‘kuka’ and are used to make “kuka soup”    (http://en.wikipedia.org/wiki/baobab). The baobab leaves are tender in rainy season and are harvested fresh in the last month of the rainy season, sun dried and either stored as whole leaves or pounded and sieved into a fine powder. In the market the powder is the most common form (Sidebe et al., 1998). Dried green leaves are used throughout the year, mostly in soups served with the staple dish of millet (Delisle et al., 1997). Baobab shades its leaves at beginning of the dry season and new leaves appear after flowering. Baobab has economic potential locally and internationally (Vertueni et al., 2002). Nnam & Nwofor (2001) reported that baobab leaves, fruits and seeds are used as articles of food in the northern states of Nigeria where it grows extensively but are not consumed in the southern state.

Figure 1 Adansonia digitata

              

                                  

1.8.1 Discovery and Naming

The vernacular name “Baobab” is derived from Arabic (Būħibāb), which means "father of many seeds". The scientific name “Adansonia” refers to the french explorer and botanist, Michel Adanson (1727-1806), who discovered it in 1749 on the island of Sor, Senegal. (Michel Adanson 2015). 

When théodore monod searched the island in the 20th century, the tree was not to be found however. Adanson concluded that the baobab, of all the trees he studied “is probably the most useful tree in all.” he consumed baobab juice twice a day, while in Africa. He remained convinced that it maintained his health for him.(the baobab tree, 2015 ) "Digitata" refers to the digits of the hand. The baobab's compound leaves with normally five (but up to seven) leaflets are akin to a hand. (Du Plessis& Doep 2011)

Plant Profile

Kingdom: Plantae

(Unranked): Angiosperms

(Unranked): Eudicots

(Unranked): Rosids

Order: Malvales

Family: Malvaceae

Genus: Adansonia

Species: A. Digitata

Common Names: White Crossberry, Phalsa Cherry, Raisin Bush, Angara,

Gangu, Kanger and Kuka.

1.8.2 Habit and Physical Description

The trees usually grow as solitary individuals, and are large and distinctive

Elements of savannah or scrubland vegetation. 

All baobab trees are deciduous, losing their leaves in the dry seasons, and remains leafless for nine months of the year. They can grow to between 5–25 m (16–82 ft) in height. They are in fact known both for their height and trunk's girth. The trunk tends to be bottle shaped and can reach a diameter of 10–14 m (33–46 ft). (Encyclopedia of life 2015) the span of the roots actually exceeds the tree's height, a factor that enables it to survive in a dry climate. Many consider the tree to be “upside-down” due to the trunk likeness to a taproot and the branches akin to finer capillary roots. The trunk is smooth and shiny and can range from being reddish brown to grey. The bark can feel cork-like. (The baobab tree, 2015) the branches are thick and wide and very stout compared to the trunk. During the early summer (October to December In southern hemisphere) the tree bears very large, heavy, white flowers. These are 12 cm (4.7 in) across and open during the late afternoon to stay open for one night.

1.8.3 Food Uses and Nutrition

The Baobab Is A Traditional Food Plant In Africa, But Is Little-Known Elsewhere. The vegetable has been suggested to have the potential to improve nutrition, boost food security, foster rural development, and support sustainable land care. (national academies press 2008) the African baobab fruit contains 50% more calcium than spinach, is high in antioxidants, and has three times the vitamin c of an orange. (The tree of life 2015).  The dry pulp is either eaten fresh or dissolved in milk or water to make a drink. The leaves can be eaten as relish. Young fresh leaves are cooked in a sauce and sometimes are dried and powdered. The powder is called Lalo in Mali and sold in many village markets in western Africa. Oil extracted by pounding the seeds can be used for cooking but this is not widespread. (Sidibe, M& Williams, J.T 2002) in Sudan, where the tree is called tabeldi, people make tabaldi juice by Soaking and dissolving the dry pulp of the fruit, locally known as gunguleiz. (Gartenbauwissenschaft 2002) (springer.com 2015) in 2008, the European Union approved the use and consumption of baobab fruit as an ingredient in smoothies and cereal bars. (novel foods and processes 2008) the united states food and drug administration granted generally recognized as safe status to baobab dried fruit pulp as a food ingredient in 2009.(Laura M. Tarantino 2009) baobab leaves are sometimes used as forage for ruminants in dry season. The Oilmeal, which is a byproduct of oil extraction, can also be used as animal feed. (Heuze, V Tran & G Bastianelli 2013) in times of drought elephants consume the juicy wood below its bark. (Sheehan& Sean 2004).

1.8.4 Nutrients in Adansonia digitat Leafy Vegetables:

The leaves of the baobab tree have rich nutrient potentials. FAO (1990) reported its protein value as 12.3%, 3.1% fibre, 9.6% ash, 11.8% moisture, 221mg calcium, 24mg iron, 275mg phosphorus, and traces of ascorbate. Nnam and Nwofor (2001) identified that baobab leaf would be useful in providing macro and micronutrients to the diets of people who consume it. They ascertained that pulverized baobab leaf soup is a potential good source of calcium (147mg), phosphorus (0.02mg) and provitamin A (89.61mcg) per 100g dry weight basis (Nnam & Nwofor 2001). Kamali and Khalifa (1999) detected a content of provitamin A of 27mg Retinol equivalents per gram of the dried leaves and identified that shade drying increases the value. Equally Stefano (2002) reported content of rhamanose and other sugars in dry leaves of Adansonia digitata. The leaves of Adansonia digitata are important protein sources in complementing the amino acid profile and improving the protein quality of diets (Nordeide, Hatloy, Folling & Oshaug, 1996). Glew, Vanderjafit , Lockett, and Millsan (1997) reported a total lipid of 55mg/g in dry weight bases in Adansonia digitata leaves.

Ethnobotanical studies have confirmed the high content of antioxidant vitamins in Adansonia digitata fruit constituents and leaves. Baobab fruit pulp can be considered a much valuable source containing levels of vitamin C ranging 2.8-3 g/kg (Vertuani et al., 2002).The Adansonia digitata leaves are also rich in vitamin C (55mg/100g), iron (23mg/100g) and calcium (400mg/100g) (www,actahor./book/806/506.40htmtorg) . Baobab leaves contain high amounts of tannins as tannic acid. Stefano (2002) reported that high tannins content of the leaves of Adansonia has a marked negative effect on their digestibility in livestock.

1.8.5 Anti nutrients in Adansonia digitat Leafy Vegetables:

Adansonia digitata leaves have higher content and concentration of saponin than those of the fruits (Dike 2010). The leaves contain substantially high crude fibre. Stafano (2002) reported that Adansonia digitata dry leaves and fruit pulp have higher values of antioxidant phytochemicals when compared with other vegetables. Scheuring, Sidibe and Frigg (1999) identified baobab leaf as rich source of beta-carotene, the precursor of vitamin A (156.5mcg/g).

CHAPTER TWO: MATERIALS AND METHODS

2.1 Materials

2.1.1 Procurement of Plant Materials

The vegetable used in the study was Adansonia Digitata (baobab) leaves. The leafy vegetable were obtain fresh in June 2018 from Malam Sani farm land located at Tungar Dotti Gwadangaji, Kebbi State Nigeria.  The Vegetable Were Identified at the Department of Botany, Kebbi State University of Science And Technology Aliero. By Dr. Drahmendra Singh with V.N of 266.

2.1.2 Preparation of vegetable

The leafy vegetables were thoroughly washed with distilled water and dried under the shade for one week. The dried leaves were grounded into powder using pestle and mortar, the ground portion was kept in a plastic bottle prior analysis.

2.1.3 List of Reagents

Table 3: List of Reagents

Reagent used in the study

Reagent

Specification

Company/Country 

Xylene

Analar

England

Ethanol

BDH Chemicals

England

Phosphotungstate reagent 

Analar

England

Petroleum ether

BDH chemical

England

FeCl3

BDH Chemical

England

KOH solution

BDH Chemicals

England

Distilled water

Pure

SSU lab 

Vitamin C standard

 BDH chemical

Tokyo, Japan

H3PO4

Analar

England

 2.1.4 Equipment/Apparatus

Table 4: Equipment And Apparatus Used In The Study

Materials/Apparatus

Specification

Company/Country Name

Weighing balance

PC-4400/Metal

Tokyo/Japan

Beaker

Glass

England

Conical Flask

Glass

Pyrex, England

Measuring cylinder

Glass

Pyrex, England

Spectrophotometer

AE-350

ERMAInc./Tokyo, Japan

Water bath

GD100

Grant Instruments (Cambridge) Ltd./England

Centrifuge Machine

800D/Metal

Pipette

Robber

England

Test tube 

Glass

Pyrex England

UV lamp

China

Muffle furnace

Gallenkemp Oven 

Lento Furnace

Gallenkamp USA

2.2 Nutritive Analysis.

Nutritive analysis was done in including proximate composition (moisture, ash, crude fiber crude protein, and Crude lipid), minerals content (Sodium, potassium, Calcium, magnesium and phosphorus.) and Vitamin C content.

2.2.1 Proximate composition

The proximate composition Adansonia Digitata leafy vegetable were determined using standard methods of AOAC. All analyses were done in triplicate, the results are presented with their means and standard deviation.

2.2.2 Determination of moisture content

Principle:

The principle of moisture content determination is based on heating the sample to eliminate the water content in the sample. This is achieved by placing the sample in an oven at 105c for 24hours. High temperature is not needed to avoid decomposition of some organic compound.

Procedure:

The moisture contents of the sample were determined using AOAC (2005) 

Washed crucibles were dried in a gallenkemp oven at 100°C for about 2 hours, cooked in desiccators and reweighed. Two grams (2g) of the sample were weighed into the weighted crucible and placed in the oven at 105°C for 24 hours. The crucibles containing the samples were cooled in desiccators, weighed and dried repeatedly until a constant weight was obtained. The percentage Moisture was calculated using formula below:

      % moisture = initial wt of crucible + sample – final wt of crucible + sample   X 100

                                                                Weight of sample

2.2.3 Determination of Ash content

Principle:

The principle is based on the fact that minerals are not destroyed by high temperature. When a food materials is ashed in a muffle furnace at a high temperature of 600°C for 5 hours, all the organic matter is burnt off leaving the inorganic substance in the form of ash.

Procedure:

The ash contents of the samples were determined using the method of AOAC (2005). 

Two grams (2g) of the sample was weighed into reweighed crucibles and put into muffle furnace at 600°C for 3 hours until light gray ash is obtained. The crucibles was removed from the furnace, put in desiccators to cool and reweighed to obtain the weight of ash. The percentage ash was calculated using the formula below.

% ash = (weight of crucible + ash – weight of empty crucible)   X 100

                                       Weight of sample

2.2.4 Determination of Crude lipid

Principle:

The ether extraction method is based on the fact that compounds of low solubility are extracted from a solid mixture with 10mls petroleum ether, which dissolves the fats, oils, pigments and other fat soluble substances, since petroleum ether has a low boiling point of (40-80°C), therefore when boiled at low temperature in a flask to Soxhlet apparatus using a reflux condenser. The vapor of the boiling petroleum ether condenses and falls into the extracting chamber where the lipid content is extracted and washed down to a flask.

Procedure:

Using AOAC (1995)

Two grams (2g) of the dried sample was transferred in to a dried and weighed thimble. The thimble containing the powdered sample were weighed (W2) and mouth porous thimble were covered with fat free absorbent cotton wool in order to distribute the dropping petroleum ether. The thimble was then placed in soxhlet extractor fitted to a round bottom flask containing 150cm of petroleum ether. The apparatus was switched on for 5 to 6 hours at 500C. After this, the thimble was removed from the soxhlet and weighed. The flask was removed with care and the organic solvent was evaporated. Finally, the extracted flask containing the oil was weighed to know the content of the crude lipid.

Calculation

The percentage crude lipid was calculated using the equation;

%Crude lipid = weight loss by thimble x 100

                               Weight of sample

%Crude lipid = W3 – W1     X 100

                              W2

Where

W1 = weight of empty flask

W2 = weight of sample

W3 = weight of flask + sample

2.2.5 Determination of crude protein by Micro kjeldahl Method AOAC (2005)

Principle:

The principle for Crude protein determination is based on the fact that when a sample is boiled with concentrated sulphuric acid (H2SO4) and a kjeldahl tablet added as catalyst, the H2SO4 decompose the organic substance by oxidation and convert all forms of nitrogen to the reduced form form of ammonium sulphate. The distillation of the solution with excess sodium Hydroxide (NaOH) in a closed system neutralizes the acid and convert ammonium salt to ammonium. The amount of ammonia present in the sample is determined by distilling the ammonium into boric acid solution (H2BO3) and titrates against 0.1N HCl to end point.

Equation of reaction involves 3 steps:

Digestion or degradation

Protein + Conc. H2SO4                                           (NH4)2 SO4 (aq) + Co2 (q) + SO4 (g) + H2O (g)

Distillation

Liberation of ammonia

NH4)2 SO4 (aq) + 2NaOH (aq)                                      Na2 SO4 (aq) 2H2O (1) +   2NH3 (g)     

Capture of Ammonia

B (OH)3 + H2O + NH3                           NH4+  +   B(OH)4 -   

Titration

B (OH)4 - + H+                                    B (OH)3 + H2O

    Procedure:

Three steps are involved in this analysis. They are digestion, distillation and titration.

Digestion 

Two grams of the sample was transferred into 250ml kjeldahl digestion flask, 20ml of concentrated H2SO4 was added and mixed gently by swirling under tap water. 10g of anhydrous Na2SO4 and 1g of CuSO4 was added and mixed together and 3g of this catalyst was introduced into the flask. Anti-burning chips was added into the mixture. The content was boiled gently in a fume cupboard until charred particles disappeared and a clear Solution was obtained, the digested mixture was maked up to 500ml with distilled water.

Distillation 

40ml of 2% boric acid was measured into 250ml beaker and 2 drops of indicator was added. Appropriately 10ml of digested sample was poured into the distillation flask and apparatus were set. The heating system was switched on for 25 minutes, the receiver beaker was then removed.

Titration

The collected distillate was cooled and titrated against 0.1N HCl acid to an end point

(Indicates change in color from grey to purple)

Calculations:

%Nitrogen can be calculated using the formulae below

 

                 %Nitrogen     =    TVX N X 0.014 X Dilution factor X 100 

                                                 Weight of sample X mls of Aliqout

Where

 N = Normality 

TV = Titer value

%Crude protein = % Nitrogen X Conversion factor (6.25)

2.2.6 Determination of Crude fiber

Principle:

During acid hydrolysis and subsequent alkali treatment, oxidative hydrolytic degradation of the native cellulose and considerable lignin occur. The residue obtain after their final filtration is weighed, incarnated, cooled and weighed again. The loss in weight gives the crude fiber content.

Procedure:

2g of the ground sample was extracted using petroleum ether to remove the fat, 

After extraction 2g of dried material was boiled with 200ml of sulphuric acid for 30 minutes with bumping chips.

The solution was filtered through muslin cloth and wash with boiling water until the washing are no longer acidic

The solution was boiled with 200ml of sodium hydroxide for 30 minutes, and filtered through muslin cloth again and washed with 2ml of boiling 1.25% H2SO4 three 50ml portions of water and 25ml of alcohol.

The residue was removed and transferred to ashing dish (preweight dsh W1).

The residue was allowed to dry for 2 hours at 130 ± 20C and cooled in desiccator and weighed (W2).

The residue was ignited for 30minutes at 600± 150C, cooled in desiccator and reweighed (W3)

Calculations 

% fiber = loss in weight on ignition (W2– W1) – (W3– W1) x 100

                                             Weight of sample

Where

W1 = weight of empty crucible

W2 = weight of sample

W3 = weight of crucible + sample after drying 

2.2.7 Determination of Carbohydrates (by difference).

Total carbohydrate contents of the samples were determined by difference (subtracting crude protein, moisture, fat, fiber and ash content from 100%). The total carbohydrate of the sample was by difference.

Carbohydrate = 100 – (% protein + % fat + % ash + % crude fiber + % moisture).

2.2.8 Determination of vitamin C (Rutkowski and Grzegorczyk , 2007).

Principle:

This was based on color reaction with periodically prepared phosphotungstate reagent and absorbance taken at 700nm.

Procedure:

1ml of the analyzed liquid into the centrifugal test-tube, 1ml of the phosphotungstate (PR) was added and was mixed thoroughly and left in a room temperature for 30minutes. The tube was centrifuged (7000xg, 10 minutes) and the whole was collected from separated supernatant with a pipette. The supernatant was the test sample for spectrophotometric measurement. The standard was prepared in the same way without centrifugation. The absorbance of the test samples A and of the standard sample A was measured at 700nmagainst the mixture PR: 50m solution of oxalic acid =1:1 (v/v) was used as the reference sample.

Calculation

Cx = As    x Cs

          As

Where Cs = concentration of the standard solution =56.8μm/L

As= absorbance of sample

 As= absorbance of standard

2.2.8 Minerals Composition

2.2.9 Anti-nutritive Composition

Anti-nutrients analyzed were phytates, oxalates, nitrates, Cyanide and tannin. 

2.2.10.1 Determination of Phytate

Procedure 

The Phytate was determined using method describe bylucas and marakaka (1975)

4g of sample was soaked in 100ml of 2% HCL for 3 hours, and filterd. 25ml of the filtrate, 5ml of 0.3%NH4SCN, and 53ml of distilled water, were mixed together and titrated against 0.01N standard ferric chloride FeCl3 solution containing 0.00195g/ml until a brownish yellow color persisted for 5 minutes.

Calculations

(% Phytate mg %)

Titrate value X 1.19 = phytin phosphorus

Phytate content = phytin phosphorus X 3.55

2.2.9.2 Determination of oxalate

Principle

Oxalate is precipitated as calcium oxalate, the concentration is determined by titration with potassium permanganate which gives a paint pink end point.

Procedure

1g of sample was added to 75ml of 15% H2So4 the solution was carefully stirred intermittently with a magnetic stirrer for 1 hour and filtered using whatman No. 1 filter paper, the filtrate (25ml) was then collected and titrated against 0.1N KMNO4 solution till a paint pink color appeared that persisted for 30 seconds. 1cm3 of 0.1N KMNO4 = 0.0045g of oxalic acid.

Calculations

(%oxalate g %) = Titer value X 0.0045 

2.2.9.3 Determination of Nitrate

Nitrate was determined using method of ILTA (1988)

Procedure

0.1g of powder sample was added into 100ml conical flask, 10ml of distilled water was added and boiled for 30 minutes and filtered using filter paper.

Table 5: Procedure for determination of nitrate

Reagents

Test

Standard

Blank

Sample

Standard sodium nitrate

DH2O

5% Salicylic Acid

Mixed and incubate for 20 minutes 

    0.2ml  

        _

   

        _

     0.8ml

           _

       0.2ml 

           _

       0.8ml

           _

            _

        0.2ml

        0.8ml

 

2N NaOH

19ml

19ml

19ml

Mixed and was allowed to cool, the absorbance was measured at 410nm

                              

  

                                              Calculations (% nitrate mg %)

                                                      Absorbance of sample      X Concentration of standard

                                                     Absorbance of Standard

2.2.9.4 Determination of Tannins

Tannins were determined by the method of (Trease, and Evans 1978) 

Principle

The method is based on quantitative consumption of tannins and pseudo tannins to iodine in Alkaline medium, a character which is attributed to their phenolic nature. True tannins, in contrast to pseudo tannins can be removed from extract by precipitation with gelatin, this can permit the determination of each group of constituent alone. Excess iodine is determined by titration, rendering acidic with thiosulphate solution.

Procedure

Powdered sample (100mg) was put into 100ml conical flask, 50ml of distilled water were added and boiled for 30 minutes, in a boiling water and filtered using filter paper.

Table 6: Procedure for Determination of Tannins

 

Reagents

Test

Standard

Blank

Sample

Standard Tannic Acid

DH2O

17% sodium carbonate

Folin Dennis reagent

 10ml

              _

              _

       10ml

       2.5ml

   _

   _

  10ml

  2.5ml

   _

   _

 10ml

 2.5ml

Mixed and incubated for 20 minutes at room temperature, and absorbance was measured at 760nm 

Calculations (% of Tannic acid mg %)

 Absorbance of sample     X Concentration of standard

Absorbance of Standard

2.2.9.5 Determination of Cyanide

Cyanide was determined using method reported by (Rails 1992)

Procedure

0.5g of powdered sample was measured into 100ml of conical flask and 50ml of distilled water was added and boiled for 30 minutes and filtered using filter paper.

Table 7: procedure for determination of cyanide

Reagents

Test

Standard

Blank

Sample

Standard KCN

DH2O

Alkaline picrate

         1ml 

            _

              _

4ml

              _

           1ml

              _

           4ml

              _

              _

1ml

4ml

Mixed and boiled for 5 minutes. The solution was allowed to Cooled and absorbance was measured at 490nm.   Calculations   

                                              Absorbance of sample     X Concentration of standard

                                            Absorbance of Standard

CHAPTER THREE: RESULT

3.1 Proximate and Ascorbic Acid Composition

Table 3.1 present the proximate and Ascorbic acid composition of Adansonia Digitata leafy vegetable, Adansonia Digitata leaves had 9.9% moisture, 8.9% Ash, 3.9% fiber, 14% protein, 0.9% lpid and % 66.9 carbohydrate. While the concentration of vitamin C was found to be 321mg.

Table 8: Proximate and Ascorbic acid composition of Adansonia digitata, leafy vegetable

            Parameters                                                                                  Concentrations mg g-1

Moisture 9.9±0.1

 Ash 8.9±0.2

 Fiber 3.9±0.1

Protein 14±0.2

Lipid 0.9±0.8 

Carbohydrate 66.9±7.9

Ascorbic acid 321±0.8      

Mean ±SD, n=3

Table 3.2 present the mineral composition of Adansonia Digitata leafy vegetable, the leaves had 1.2mg Calcium, 1.4mg magnesium, 4566.7mg potassium, and 9.1mg of phosphorus.

3.2 Minerals

Table 9:  Some Minerals composition of Adansonia digitata, leafy vegetable

Elements                                                                             Concentrations mg g-1

 Ca 1.2±0.1

Mg 1.4±1.2

K 4566.7±115.5

Na        77.5±5

P 9.1±7.4        

                                                               

Mean SD, n=3

Table 3.3 present anti-nutritive content of Adansonia Digitata leafy vegetable, the leaves had 18.6 mg Phytate, 0.006mg oxalate, 132.5mg tannins, 7.3mg nitrate and 0.3mg of cyanide. `

3.3 Anti-nutrient

Table 10: Some Anti nutritive Factors of Adansonia digitata, leafy vegetable

Anti-nutritive factors                                                          Concentrations mg g-1

 Phytate 18.6±0.4

Oxalate 0.006±0.0004

Tannins 132.5±0.1

Nitrate 7.3±0.8

Cyanide  0.3±0.4                                                                           

Mean ±SD, n=3

CHAPTER FOUR

DISCUSSION, CONCLUSION AND RECOMMENDATIONS.

4.1 Discussion

4.1.2 Proximate and Ascorbic Acid Composition

Moisture

The result revealed that the leaf has a moisture content of 9.9% which is higher than 3.21%  Reported for Moringa oleifera but closer when compared to11.82 %, 10.25% reported for Hibiscus cannabinus and Haematostaphis barteri respectively.

Moisture content is a widely used parameter in the processing and testing of food. It is an index of water activity of many foods and helps in maintaining protoplasmic content of the cell and the texture of leaf. The observed value implies that A. digitata could have a long shelf life since microorganisms that cause spoilage mostly thrive in foods having high moisture content. This also is an indication of high total solids content in the leaf.

 Vegetables with high moisture content are called high water content foods with 80-95% of their total composition being water (Iheanacho and Udebuani 2009). This shows that the more of the vegetables consumed, the more water intake that flushes out waste products from the body (www.healthy-eating.and. nutrition. co).

Ash

The ash content which is a measure of inorganic matter in A. digitata was 8.9%. This value was closer to the value (9.03%) in A. esculentus leaves reported by Javid Hussain et al. 2009, the value was higher compared to the ash contents 1.35%, 0.33% and 0.06% reported by Nwanko Rita Ngozi 2014 in Hibiscus cannabinus, Sesamun indicum and Cassia tora leaves but low when compared to 12.19% ash content reported by Muibat Olabisi Bello et al. 2014 in ficus exasperate vahl leaves. Leaves with high ash content are good sources of minerals needed for the body and the high value indicated that A. Digitata could be a good source of mineral elements.

Fiber

Crude fibre present in A. Digitata was 3.9%. This was closer to the value reported by Nwankwo Rita Ngozi 2014 in A. digitata leaves (4.16%) and was higher when compared to the fiber content of A. sativum(1.8%) reported by Javid hussien et al. 2009., The value is higher when compared to the fiber content reported by Nwankwo 2014 in sesamuna indicum (1.9%) but lower when compared to that of Hibiscus cannabinus leaf (29.61%) This high level of dietary fiber in leafy vegetable are advantageous for their active role in the regulation of intestinal transit, increasing dietary bulk and increasing faeces consistency due to their ability to absorb water. Fibers are known to slow down glucose absorption and reduce insulin secretion which is of great importance to diabetic patients.

Protein

The crude protein content of A. digitata leaves was 14%, the value was similar to 14.71% reported by javid Hussien et al. 2009 in A. esculentus. The value was found to be closer when compared to the observed values in conventional vegetables like cabbage, 12.8%; and lettuce, 14% but lower than 17.09% in Moringa oleifera leaf.  The value implies that A. digitata is good source of proteins Even though the leaf might not serve as a sole source of protein for the alleviation of Protein Energy Malnutrition, but when rightly combined with other foods it could be of high biological value and satisfactorily meet the protein needs of man.

Fat

Crude lipid in A. Digitata leaves was found to be of 0.1% the fat level was the least in the proximate components. This is in line with the observation of Nnam et al. (2012) that among the proximate components, fat content represents the lowest in vegetables, also Green leafy vegetables are known to be poor source of fat (en.wikipedia.org/wiki/leaf. Veg.)

the value was higher when compared to 0.05% lipid content of hibiscus cannabinus and cassia tora reported by Nwanko, Rita Ngozi 2004 but lower when compared to lipid content of fiscus exasperate leaves reported by muibat olabisi Bello 2004 This implies that A. Digitata leaves are poor source of lipid which is typical of most leafy vegetables., Excess fat consumption is implicated in cardiovascular disorders such as atherosclerosis.

Carbohydrate

The carbohydrate content of A. digitata leaves was found to be 66.09%, this was higher compared to the reported finding of Akinwumi et al. 2016 in Vernonia amygdalina (34.5%), and amaranthus dubius (37.20%), the value was lower compared to carbohydrate content of ficus exasperate vahl leaves (72.81%) reported by Muibat olabisi bello, 2014.  The level of carbohydrate in the leaf is high and thus it could be a source of energy required for the smooth functioning of the body. The level was found to be high despite the fact that vegetables are not good source of carbohydrates.

Carbohydrate contents in A. digitata could supply part of the daily requirements for carbohydrates for the individual. The end product of carbohydrate digestion (glucose) provides energy to cells in the body particularly the central nervous system (Effiong, Ibia, Udofia, 2009).

Vitamin C

The vitamin C content of A. digitata leaf was 321 ± 0.08 mg /100g. this is very high compared to 23.45 and 18.96 reported by Nwankwo Rita Ngozi 2014 in Hibiscus cannabinus and cassia tora, the value is extremely very high compared to 0.09924±0.001 reported by Muibat olabisi Bello et al. 2014 in Ficus exasperate vahl leaves. The higher value implies that A. digitata leaves were excellent source of Vitamin C and this is in line with literature reported by Meddison et al. (2007)   that A. digitata fruits contains three times the vitamin c of orange whereas the leaves are nutritionally superior to its fruits. Vitamin C is a highly effective antioxidant and a very small daily intake of this vitamin for an adult is required to avoid deficiency disease scurvy. 

Even in small amounts it can protect indispensable molecules in the body, such as proteins, lipids (fats), carbohydrates, and nucleic acids (DNA and RNA) from damage by free radicals and reactive oxygen species that can be generated during normal metabolism as well as through exposure to toxins and pollutants. 

4.1.3 Mineral composition

The result of the study showed that Adansonia Digitata leaves were good source of some minerals as shown in Table 3.2. The mineral content of A. Digitata leaves indicates the concentration of potassium to be highest 4566.7mg. Sodium contents was 77.5mg. The concentration of magnesium and calcium were 1.4mg, 1.2mg and the concentration of phosphorus was 9.1mg respectively.

The values indicate that Adansonia Digitata leaves were good source of potassium, sodium and phosphorus. Potassium plays a critical role in transmission of nerve impulses, muscle contraction and maintenance of normal blood pressure. Sodium is required for the maintenance of osmotic pressure and fluid balance. lt is necessary for the normal muscle irritability and cell permeability.  The higher value implies that A. digitata is an excellent source of sodium, for normal individuals, the requirement of sodium is about 5-10 g/day which is mainly consumed as NaCl. While Phosphorus aid in metabolic reactions (as component of DNA and RNA, ADP, ATP and TPP). 

4.1.4 Anti-nutritive composition

Phytate

The Phytate content of A. digitata was found to be 18.6 ±0.4, this is higher compared to the 11.4 ±0.7 and low compared to the 33.1 ±0.6 in A. digitata and Cassia tora reported by kajo fidelia 2012. Miller reported that Phytate content of plant in many cases vary depending upon the variety, climate conditions and type of soil. High level of phytic acid are of nutritional significance as phytic acid might decrease bioavailability of minerals. The insoluble complex, so formed , resist breakdown in the digestive tract  resulting in the reduced availability of this minerals in non-ruminants this happens when its level is high but at low level it exert beneficial effect to the body. The Phytate content in A. digitata can be substantially eliminated by Heating or boiling the leaves so as to inactivate the antinational factors.

Oxalate

The result showed that oxalate content of A. digitata leafy vegetable was 0.006±0.0004, this amount is insignificant so it cannot cause any detrimental effect to human body but might exert a beneficial effect to the body since some Anti nutritional factors are known to cause harmful effect only when there present high amount. Oxalates can have a harmful effect on human nutrition and health, especially by reducing calcium absorption and aiding the formation of kidney stones (Fekadu et al. 2013). High‐oxalate diets can increase the risk of renal calcium oxalate formation in certain groups of people (Gemede and Ratta 2014). The majority of urinary stones formed in humans are calcium oxalate stones and currently, patients are advised to limit their intake of foods with a total intake of oxalate not exceeding 50–60 mg per day (Massey et al. 2001). The oxalate content of A. digitata leaves analyzed in this study are low compared to the recommendations for patients with calcium oxalate kidney stones. Under these guidelines, A. digitata could be recommended not only for healthy people but also consumption for patients with a history of calcium oxalate kidney stones.

Tannins

The tannin content of A .digitata leaves was (132.5 ±0.1mg), this is slightly high compared to the value (122.95 ±1.10mg) reported by muibat olabisi belllo et al., 2014 in f. exasperate leaves.

The value were higher than the safe level of tannins (0.15 - 0.20mg) as recommended by Schiavono et al. (2007). However, Gibson (2007) suggested that traditional methods of food preparation could reduce certain anti nutrients and increase the nutritive value of vegetables. In line with this, proper methods of food preparation could reduce the tannin levels and boost the phytochemical properties of the vegetables. Willy (2003) observed that tannins are anti-nutrients with antioxidant effects. They were traditionally considered anti-nutritional but it is now known that their beneficial or anti nutritional properties depend upon their chemical structure and dosage.

 At lower levels they act as beneficial antioxidants while at higher levels they act as cataion agents, preventing availability of certain nutrients (Willy, 2003). Tannins form complexes with proteins, carbohydrates and certain metal ions (Nnam and Onyeke, 2003). The tannin- protein, tannic acid – starch and tannin metal complexes are resistant to enzyme hydrolysis, thus inhibiting the digestibility and absorption of nutrients (Nnam and Onyeke, 2003). 

The high levels of tannins in A. digitata leafy vegetables are an indication that proper methods of preparation must be used to reduce the levels and prevent the tannin complexes that inhibit absorption of nutrients.

Cyanide

The Hydrogen cyanide content was 0.3 ±0.4mg this was closer to the value o.23 ±0.008 in A. digitata leaves and higher compared to the 0.02 ±0.00mg in leptadenia hastate reported by kajo fidelia 2012. Anhwange reported that Hydrogen cyanide content in diet can cause neurological respiratory, cardiovascular and thyroid debilities. Cyanide prevent cell from using oxygen by inhibiting an enzyme called cytochrome C oxidase which transport electron to oxygen during respiration. The low levels of hydro cyanides in A. digitata leafy vegetables (0.3 ±0.4mg/100g) are beneficial to health. This is because high level hydrocyanins produced from cyanogenic glycosides when consumed in large quantity over long periods may prove toxic. Simple food preparation methods would remove the little hydrocynins and leave the vegetables safe for human consumption.

Nitrate

The nitrate content was 7.3 ±0.8mg, Nitrates may be chemically changed in the digestive tract into poisonous/carcinogenic nitrosamines. High level of nitrates in vegetables when ingested can be converted to nitrite which can lead to cancer and metheamoglobinemia or blue-baby disease (Gupta et al., 2000 ;). Boiling the leaves of A. digitata for some minutes, then discarding the water alleviates both oxalate and nitrate problems (Ogbadoyi et al., 2006). 

4.2 Conclusion

 The results suggest that A. digitata leaves are good source of nutrients like carbohydrate, proteins and minerals. The leaves if consume in sufficient amount would contribute greatly to the nutritional requirement for normal growth and adequate protection against diseases arising from malnutrition. 

The most remarkable finding of this study is that Adasonia digitata were found to be an excellent source of vitamin C.  

Interestingly, the anti-nutritional contents of the A. digitata were low excluding Tannins, so the bioavailability of nutrient were high and therefore, its consumption is encouraged as additional source of nutrients to the diet and could be employed in fortification, formulation and supplementation of other food materials.

4.3 Recommendation

Further studies can be done on effects of cooking and processing methods such as drying on the various nutritional components of the Adansonia digtata leaves, and the best method that preserves nutrients and destroys anti-nutrients be established. 

Studies on composition of other wild edible plants can also be done and compared with that of Adansonia digtata to establish the most nutritious vegetables.

REFERENCE

(Asaolu, Adefemi, Oyakilome, Ajibulu, & Asaolu, 2012)Asaolu, S. S., Adefemi, O. S., Oyakilome, I. G., Ajibulu, K. E., & Asaolu, M. F. (2012). Proximate and Mineral Composition of Nigerian Leafy Vegetables. Journal of Food Research; Vol. 1, No. 3; 2012, 1(3), 214–218. https://doi.org/10.5539/jfr.v1n3p214

Bello, M. O., Abdul-hammed, M., & Ogunbeku, P. (2014). Nutrient and Anti-nutrient Phytochemicals in Ficus exasperata Vahl Leaves. International Journal of Scientific & Engineering Research, Volume 5, Issue 1, January-2014 2177, 5(1), 2177–2181.

Chadare, F. J. (n.d.). Baobab ( Adansonia digitata L .) foods from Benin : composition , processing and quality.

Habibat, A., Olorunfemi, O., Eunice, O., & Emmanuel, A. (2016). Nutritional and antinutritional attributes of under - utilized tree crops: adansonia digitata, albizzia lebbeck and daniellia oliveri seeds, 2(1), 24–33.

Patience, N. O., Nweke, O. L., & A, A. I. (2016). Comparative Proximate Analyses of Pterocarpus santalinoides and Ficus carpensis Leaves from Abakaliki , Ebonyi State , Nigeria Abstract :, 4, 877–881.

Shahnawaz, M., Sheikh, S. A., & Nizamani, S. M. (2015). Determination of Nutritive Values of Jamun Fruit ( Eugenia jambolana ) Products Determination of Nutritive Values of Jamun Fruit ( Eugenia jambolana ) Products, (August 2009). https://doi.org/10.3923/pjn.2009.1275.1280

(Shahnawaz, Sheikh, & Nizamani, 2015)Asaolu, S. S., Adefemi, O. S., Oyakilome, I. G., Ajibulu, K. E., & Asaolu, M. F. (2012). Proximate and Mineral Composition of Nigerian Leafy Vegetables. Journal of Food Research; Vol. 1, No. 3; 2012, 1(3), 214–218. https://doi.org/10.5539/jfr.v1n3p214

Bello, M. O., Abdul-hammed, M., & Ogunbeku, P. (2014). Nutrient and Anti-nutrient Phytochemicals in Ficus exasperata Vahl Leaves. International Journal of Scientific & Engineering Research, Volume 5, Issue 1, January-2014 2177, 5(1), 2177–2181.

Chadare, F. J. (n.d.). Baobab ( Adansonia digitata L .) foods from Benin : composition , processing and quality.

Habibat, A., Olorunfemi, O., Eunice, O., & Emmanuel, A. (2016). Nutritional and antinutritional attributes of under - utilized tree crops: adansonia digitata, albizzia lebbeck and daniellia oliveri seeds, 2(1), 24–33.

Patience, N. O., Nweke, O. L., & A, A. I. (2016). Comparative Proximate Analyses of Pterocarpus santalinoides and Ficus carpensis Leaves from Abakaliki , Ebonyi State , Nigeria Abstract :, 4, 877–881.

Shahnawaz, M., Sheikh, S. A., & Nizamani, S. M. (2015). Determination of Nutritive Values of Jamun Fruit ( Eugenia jambolana ) Products Determination of Nutritive Values of Jamun Fruit ( Eugenia jambolana ) Products, (August 2009). https://doi.org/10.3923/pjn.2009.1275.1280

(Patience, Nweke, & A, 2016)Asaolu, S. S., Adefemi, O. S., Oyakilome, I. G., Ajibulu, K. E., & Asaolu, M. F. (2012). Proximate and Mineral Composition of Nigerian Leafy Vegetables. Journal of Food Research; Vol. 1, No. 3; 2012, 1(3), 214–218. https://doi.org/10.5539/jfr.v1n3p214

Bello, M. O., Abdul-hammed, M., & Ogunbeku, P. (2014). Nutrient and Anti-nutrient Phytochemicals in Ficus exasperata Vahl Leaves. International Journal of Scientific & Engineering Research, Volume 5, Issue 1, January-2014 2177, 5(1), 2177–2181.

Chadare, F. J. (n.d.). Baobab ( Adansonia digitata L .) foods from Benin : composition , processing and quality.

Habibat, A., Olorunfemi, O., Eunice, O., & Emmanuel, A. (2016). Nutritional and antinutritional attributes of under - utilized tree crops: adansonia digitata, albizzia lebbeck and daniellia oliveri seeds, 2(1), 24–33.

Patience, N. O., Nweke, O. L., & A, A. I. (2016). Comparative Proximate Analyses of Pterocarpus santalinoides and Ficus carpensis Leaves from Abakaliki , Ebonyi State , Nigeria Abstract :, 4, 877–881.

Shahnawaz, M., Sheikh, S. A., & Nizamani, S. M. (2015). Determination of Nutritive Values of Jamun Fruit ( Eugenia jambolana ) Products Determination of Nutritive Values of Jamun Fruit ( Eugenia jambolana ) Products, (August 2009). https://doi.org/10.3923/pjn.2009.1275.1280

Asaolu, S. S., Adefemi, O. S., Oyakilome, I. G., Ajibulu, K. E., & Asaolu, M. F. (2012). Proximate and Mineral Composition of Nigerian Leafy Vegetables. Journal of Food Research; Vol. 1, No. 3; 2012, 1(3), 214–218. https://doi.org/10.5539/jfr.v1n3p214

Bello, M. O., Abdul-hammed, M., & Ogunbeku, P. (2014). Nutrient and Anti-nutrient Phytochemicals in Ficus exasperata Vahl Leaves. International Journal of Scientific & Engineering Research, Volume 5, Issue 1, January-2014 2177, 5(1), 2177–2181.

Chadare, F. J. (n.d.). Baobab ( Adansonia digitata L .) foods from Benin : composition , processing and quality.

Habibat, A., Olorunfemi, O., Eunice, O., & Emmanuel, A. (2016). Nutritional and antinutritional attributes of under - utilized tree crops: adansonia digitata, albizzia lebbeck and daniellia oliveri seeds, 2(1), 24–33.

Patience, N. O., Nweke, O. L., & A, A. I. (2016). Comparative Proximate Analyses of Pterocarpus santalinoides and Ficus carpensis Leaves from Abakaliki , Ebonyi State , Nigeria Abstract :, 4, 877–881.

Shahnawaz, M., Sheikh, S. A., & Nizamani, S. M. (2015). Determination of Nutritive Values of Jamun Fruit ( Eugenia jambolana ) Products Determination of Nutritive Values of Jamun Fruit ( Eugenia jambolana ) Products, (August 2009). https://doi.org/10.3923/pjn.2009.1275.1280

(Habibat, Olorunfemi, Eunice, & Emmanuel, 2016)

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