CHEMICAL COMPOSITION OF SOME LESSER-KNOWN WILD … · PG/M.Sc/03/34109 has satisfactorily completed the project report for the award of Master of Science (M.Sc) degree in Human Nutrition

i

CHEMICAL COMPOSITION OF SOME LESSER-KNOWN WILD

FRUITS AND VEGETABLES CONSUMED IN AYAMELUM LOCAL

GOVERNMENT AREA OF ANAMBRA STATE

BY

ONUEKWE MONICA EKWUTOSI

REG. NO: PG/M.Sc /03/34109

DEPARTMENT OF HOME SCIENCE, NUTRITION AND DIETETICS

FACULTY OF AGRICULTURE,

UNIVERSITY OF NIGERIA,

NSUKKA.

MARCH, 2012

i

APPROVAL PAGE

THIS PROJECT REPORT HAD BEEN APPROVED FOR THE DEGREE OF

MASTERS OF SCIENCE IN HUMAN NUTRITION OF THE UNIVERSITY OF

NIGERIA, NSUKKA

BY

__________________________ ________________________

Professor N.M. Nnam Date

Supervisor

_________________________ ________________________

Professor N.M. Nnam Date

Head of Department

__________________________ _______________________

External Examiner Date

ii

CERTIFICATION

Onuekwe Monica Ekwutosi a post graduate student of Home Science, Nutrition and

Dietetics, Faculty of Agriculture, University of Nigeria, Nsukka, with registration number

PG/M.Sc/03/34109 has satisfactorily completed the project report for the award of Master of

Science (M.Sc) degree in Human Nutrition. The work embodied in this project is original and

has not been submitted in part or in full to any other institution in part or in full to a degree or

diploma.

___________________________ ___________________________

Professor N. M. Nnam Professor N. M. Nnam

(Supervisor) (Head of Department)

Date_______________________ Date_______________________

iii

DEDICATION

This work is dedicated to my husband and children and to God to whom alone belong all

praise and glory.

iv

ACKNOWLEDGEMENTS

The researcher wishes to acknowledge with humility and profound gratitude of her

supervisor, Professor N. M. Nnam for her invaluable guidance, patience, useful criticism,

encouragement for the success and completion of this research.

Her thanks and gratitude also go to all the lecturers in the Department of Home

Science, Nutrition and Dietetics, especially Prof. (Mrs.) E. C Okeke, Prof. Obizoba and Miss

Udenta E. A. for their encouragement and concern in her research.

Her appreciation also goes to her lovely husband Mr. Ignatius Onuekwe, her brother, Mr.

Paul Nwunonye and her sister and her husband Mr. and Mrs. Obodoeze for their unending

love, moral. Spiritual, and financial support without which her education and stay in the

University of Nigeria and the pursuit of her dream would have been impossible. Her

appreciation also goes to her brother-in-laws, Mr. Stephen Onuekwe and Benchuks Onuekwe,

they have been a source of encouragement. She also wishes to appreciate the wonderful

encouragement of her friends Mrs. E. N. Chukwuemeka and Mrs. B. N. Obi-Agunwa. You

are the best anyone can have.

Above all she gives thanks to Almighty God for giving her life, strength, grace, mercy to

pursue her education.

v

ABSTRACT

The study identified some edible fresh wild green leafy vegetables and fruits and determined

their nutrients, antinutrients and food toxicants content. The proximate, micronutrients,

antinutrients and food toxicants contents of these fruits (Olax viridis (“Osenga”),

Gongronema species (“Aado”), Ficus carpensis (“Akankolo”), Napoleona/imperialis

(“Ukpodikili”), Afromonum species) (“Okwocha”) and vegetables Vitex doniana (“Uchkulu”)

and Ficus carpensis) were determined using standard methods. The moisture content of the

fruits ranged from 59.83 to 75.40% in Olax viridis (“Osenga”) and Gongronema species,

(“Aado”) respectively. Olax viridis (“Osenga”) fruits had high levels of protein (6.52%),ash

(12.52%),and fibre (13.58%).Fiscus crapensis (“Akankolo”) fruit contained appreciable

quantities of ascorbate (36.mg).Gongronema species fruit is rich in iron (23.50mg),

phosphorus (44.66mg), copper (14.06mg) and zinc(12.43mg). The fruits equally contained

high levels of phytate (12.60-108mg) in Gongronema species (“Aado”) and Olax viridis

(“Osenga”). Afromonum species (“Okwocha”) had high oxalate (127.22mg). Tannins and

saponins levels of the fruits were low (0.05-0.12mg and 0.02-0.30mg), respectively. Ficus

carpensis (“Akankolo”) leaf had high moisture (60.44%) and low protein (2.18%), fat

(3.42%), ash (10.5%),fibre(8.91%) .Vitex doniana (“Uchakulu”) had less than 50%

carbohydrate (35.74%) and high fibre(11.45%). Vitex doniana (“Uchakulu”) leaf contained

appreciable amounts of β-carotene (67.83mg), and Fiscus carpensis (“Akankolo”) leaf had

lower B-carotene (27.94mg) relative to that of Vitex doniana (“uchakulu”) .07.83mg. The

ascorbate level (67.83mg) was high in Vitex doniana. Vitex doniana leaf had appreciable

quantities of phosphorus (28.63mg) and high oxalate level (128.56mg). Saponins (0.02mg)

and tannins (0.12mg) were low in the two vegetables. The edible lesser-known wild fruits and

vegetables can contribute much more nutrients especially micro nutrients to the diet of

families in Ayamelum Local Government Area of Anambra State. The antinutrients phytate,

oxalate, tannin and saponin levels of the fruits and vegetables were at safe levels. Increased

consumption of these foods is advocated.

vi

TABLE OF CONTENTS

Title page -- -- -- -- -- -- -- -- -- -- i

Approval page -- -- -- -- -- -- -- -- -- -- ii

Certification -- -- -- -- -- -- -- -- -- -- iii

Dedication -- -- -- -- -- -- -- -- -- -- iv

Acknowledgement -- -- -- -- -- -- -- -- -- v

ABSTRACT -- -- -- -- -- -- -- -- -- -- vi

Table of contents -- -- -- -- -- -- -- -- -- vii

List of Tables -- -- -- -- -- -- -- -- -- -- xi

CHAPTER ONE

1.0 INTRODUCTION -- -- -- -- -- -- -- -- --1

1.1 Background of the study -- -- -- -- -- -- -- -- 1

1.2 Statement of the problem -- -- -- -- -- -- -- -- 2

1.3 Objectives of the study -- -- -- -- -- -- -- -- 3

1.4 Significance of the study -- -- -- -- -- -- -- -- 3

CHAPTER ONE

2.0 LITERATURE REVIEW -- -- -- -- -- -- -- -- --4

2.1 Micronutrients -- -- -- -- -- -- -- -- -- 4

2.2 Importance of fruits and vegetables in diet -- -- -- -- -- 5

2.3 Mineralizing effect -- -- -- -- -- -- -- -- 7

2.4 Laxative effect -- -- -- -- -- -- -- -- -- 7

2.5 Vegetables -- -- -- -- -- -- -- -- -- -- 8

2.5.1 Leaves of the annuals and shrubs -- -- -- -- -- -- 9

2.5.2 Leaves of trees -- -- -- -- -- -- -- -- -- 9

2.6 Green leafy vegetables -- -- -- -- -- -- -- -- 9

2.7 Nutrient composition of green leafy vegetables -- -- -- -- -- 10

2.8 Composition and nutritional quality of vegetables -- -- -- -- 10

2.8.1 Carbohydrate -- -- -- -- -- -- -- -- -- 11

2.8.2 Moisture -- -- -- -- -- -- -- -- -- -- 11

2.8.3 Energy -- -- -- -- -- -- -- -- -- -- 11

2.8.4 Protein -- -- -- -- -- -- -- -- -- -- 11

2.8.5 Ether extract -- -- -- -- -- -- -- -- -- 12

2.8.6 Mineral composition -- -- -- -- -- -- -- -- 12

2.9 Vitamins in vegetables -- -- -- -- -- -- -- -- 12

vii

2.10 Antinutrient content of green leafy vegetable -- -- -- -- -- 13

2.10.1 Phytate -- -- -- -- -- -- -- -- -- -- 13

2.10.2 Oxalate -- -- -- -- -- -- -- -- -- -- 13

2.10.3 Tannins -- -- -- -- -- - -- -- -- -- 14

2.10.4 Saponins -- -- -- -- -- -- -- -- -- 14

2.11 Some commonly consumed vegetables in Nigeria -- -- -- -- 15

2.11.1 Fluted pumpkin: (Telferia occidentails) -- -- -- -- -- 15

2.11.2 Water leave -- -- -- -- -- -- -- -- -- 15

2.12 Fruits -- -- -- -- -- -- -- -- -- -- 17

2.13 Nutrient composition of fruits -- -- -- -- -- -- -- 17

2.13.1 Protein -- -- -- -- -- -- -- -- -- -- 18

2.13.2 Moisture -- -- -- -- -- - -- -- -- 18

2.13.3 Fats -- -- -- -- -- -- -- -- -- -- 18

2.13.4 Fibre -- -- -- -- -- -- -- -- -- -- 18

2.13.5 Minerals -- -- -- -- -- -- -- - -- 18

2.14 Vitamins in fruits -- -- -- -- -- -- -- -- 18

2.15 Commonly used fruits -- -- -- -- -- -- -- -- 19

2.15.1 Guava -- -- -- -- -- -- -- -- -- -- 19

2.15.2 Pineapple -- -- -- -- -- -- -- -- -- 21

2.15.3 Mangoes -- -- -- -- -- -- -- -- -- 25

2.15.4 Pawpaw -- -- -- -- -- -- -- -- -- 28

2.15.5 Orange -- -- -- -- -- -- -- -- -- -- 28

2.15.6 Avocado -- -- -- -- -- -- -- -- -- 30

2.15.7 Apple -- -- -- -- -- -- -- -- -- -- 33

2.15.8 Banana -- -- -- -- -- -- -- -- -- -- 34

CHAPTER THREE

3.1 MATERIALS AND METHODS-- -- -- -- -- -- -- -39

3.2 Pilot Study -- -- -- -- -- -- -- -- -- -- 39

3.2.1 Identification of samples -- -- -- -- -- -- -- 39

3.2.2 Preparation of materials -- -- -- -- -- -- -- 45

3.3 Chemical analysis -- -- -- -- -- -- - -- 45

3.3.1 Fat determination -- -- -- -- -- -- -- -- 45

3.3.2 Moisture determination -- -- -- -- -- -- -- 46

3.3.3 Ash determination -- -- -- -- - -- -- -- 46

viii

3.4 Crude fibre determination -- -- -- -- -- -- -- 47

3.4.1 Method -- -- -- -- -- -- -- -- -- -- 47

3.5 Crude protein determination -- -- -- -- -- -- -- 47

3.5.1 Digestion -- -- -- -- -- -- -- -- -- 48

3.5.2 Distillation -- -- -- -- -- -- -- -- -- 48

3.5.3 Titration -- -- -- -- -- -- -- -- -- 48

3.6 Carbohydrate determination -- -- -- -- -- - -- 48

3.7 Determination of iodine, iron, copper, calcium and zinc, phosphorus -- -- 49

3.8 Pro-vitamin A (RE) determination -- -- -- -- -- -- 49

3.8.1 Principle -- -- -- -- -- -- -- -- -- 49

3.8.2 Method -- -- -- -- -- -- -- -- -- 50

3.8.3 Calculation -- -- -- -- -- -- -- -- -- 50

3.9 Ascorbic acid determination -- -- -- -- -- -- -- 50

3.10 Determination of antinutrients -- -- -- -- -- -- -- 51

3.10.1 Phytate -- -- -- -- -- -- -- -- -- 51

3.10.2 Tannins -- -- -- -- -- -- -- -- -- 51

3.10.3 Saponins -- -- -- -- -- -- -- -- -- 51

3.10.4 Oxalate determination -- -- -- -- -- -- -- 51

3.11 Statistical analysis -- -- -- -- -- -- -- 52

CHAPTER FOUR

4.0 RESULTS -- -- -- -- -- -- -- -- -- -- 53

4.1 Proximate composition of fresh wild fruits -- - -- -- -- 53

4.2 Vitamin composition of fresh wild fruits -- -- -- -- -- -- 54

4.3 Mineral composition of wild fruits -- -- -- -- -- -- 54

4.4 Antinutrient composition of fresh wild fruits -- -- -- -- -- 55

CHAPTER FIVE

5.0 DISCUSSION-- -- -- -- -- -- -- -- -- -- 59

5.1 Proximate composition of wild fresh fruits -- -- -- -- -- 59

5.2 Vitamin composition of wild fresh fruits -- -- -- -- -- -- 60

5.3 Mineral composition of wild fresh fruits -- -- -- -- -- -- 61

5.4 Ant nutrient composition of wild fresh fruits -- -- -- -- -- 62

5.5 Vitamin composition of lesser-known fresh wild green leafy vegetables -- 64

5.6 Mineral composition of fresh wild green leafy vegetables -- -- -- 64

5.7 Antinutrient composition of fresh wild green leafy vegetables -- -- -- 65

ix

Conclusion -- -- -- -- -- -- -- -- -- -- 65

Recommendations -- -- -- -- -- -- -- -- -- 65

REFERENCES

x

LIST OF TABLES

Table 1: Some wild fruits and indentified for use in Ayamelum local government area

Table 2: Nutrients composition of commonly used fresh green vegetables in Nigeria, (per

100g) -- -- -- -- -- -- -- -- -- -- -- 16

Table 2: 2: vitamin composition of commonly used green leafy vegetables (mg/100g) 17

Table 3: Proximate composition of guava, raw: Psidium guajava -- -- -- 20

Table 4: Mineral composition of guava -- -- -- -- -- -- 21

Table 5: Vitamin composition of guava -- -- -- -- -- -- 21

Table 6: Nutrients composition of pineapple, raw: Ananus comosus -- -- -- 23

Table 7: Mineral content of pineapple -- -- -- -- -- -- -- 24

Table 8: Vitamin content of pineapple -- -- -- -- -- -- 25

Table 9: Proximate composition of mangoes, raw Mangifera idica -- -- -- 26

Table 10: Mineral composition of mangoes -- -- -- -- -- -- 27

Table 13: Vitamin content of mangoes -- -- -- -- -- -- 27

Table 14: Proximate composition of orange, raw, Citrus sinersis -- -- -- 29

Table 15: Mineral content of orange -- -- -- -- -- -- -- 30

Table 16: vitamin content of orange -- -- -- -- -- -- -- 30

Table 17: Avocado, raw, Persea american -- -- -- -- -- -- 31

Table 18: Mineral content of avocadoes -- -- -- -- -- -- 32

Table 19: Vitamin content of avocados -- -- -- -- -- -- 33

Table 20: Proximate composition of banana, raw: Musa paradisiacal -- -- 34

Table 21: Mineral content of banana -- -- -- -- -- -- -- 35

Table 22: Vitamin content of banana -- -- -- -- -- -- -- 35

Table 23: Proximate content of pears, raw; Pyrus communis -- -- -- 36

Table 24: Mineral content of peers -- -- -- -- -- -- -- 36

Table 25: vitamin composition of commonly used fruits in Nigeria (mg/100g) -- 37

Table 26: Proximate composition of commonly used fruits in Nigeria (%) -- -- 37

Table 27: Mineral composition of commonly used fruits in Nigeria (mg/100g) -- 38

Table 1: Some wild fruits and vegetables in Ayamelum local government area identified for

use. -- -- -- -- -- -- -- -- -- -- 39

Table 1: Proximate composition of fresh wild fruits (%) -- -- -- -- 53

Table 2: Vitamin composition of fresh wild fruits (mg /100g) -- -- -- 54

Table 3: Mineral composition of wild fruits (mg/100g) -- -- -- -- 55

Table 4: Antinutrient composition of fresh wild fruits (mg/100mg) -- -- -- 56

xi

Table 5: Proximate composition of fresh wild green leafy vegetables -- -- 56

Table 6: Vitamin composition of fresh wild green leafy vegetables (mg/100g) -- 57

Table 7: Mineral composition of fresh wild green leafy vegetables (mg/100g) -- 57

Table 8 Antinutrient composition of fresh wild green leafy vegetables (mg/100g) -- 58

1

CHAPTER ONE

1.0 INTRODUCTION

1.1 Background of the study

Micronutrient deficiency is still a public health problem in Nigeria despite the effort

that has been made to eliminate it. World Health Organization (WHO) (2002) reported that

about 30% of the population in developing countries suffer currently from one or more of the

multiple forms of nutritional deficiencies, especially that of micronutrient. Nnanyelugo

(1983) stated that incidence of malnutrition is higher in the rural areas than urban slums,

particularly protein and micronutrient deficiencies.

Onyezili et al., (2005) observed that in most developing countries three micronutrient

deficiencies are common. These are vitamin A deficiency (VAD); iron deficiency anemia

(IDA) and iodine deficiency disease (IDD). Nnanyelugo (1983) observed that deficiency

diseases were caused partly because of the food gap seasonality in which people experience

food abundance, especially vegetables during the rainy season and severe scarcity during the

dry season.

Fruits and vegetables provide people with a range of compounds, many of which have

more than one role, being involved both with immediate good health and with protection

against disease that can develop over a long period of time, such as cancer, heart conditions,

stroke, hypertention, birth defects, cataracts and diabetes.(Tenny and Barrett, 1997). Fruits

and vegetables are generally acceptable as good sources of nutrient and supplement for food

in a world faced with scarcity .They are known to be excellent source of nutrients such as

minerals and vitamins (Nhar et al., 1990)

The high incidence of malnutrition, especially in children has been seen as the core

cause of major forms of anemia in children and pregnant /nursing mothers (that is nutritional

deficiency and haemolytic anemia) (Trumb and Yates, 2001). Pamploma-Rogres (2004)

stated that fruits and vegetables have been linked to the management of anemia because of

2

they are rich in vitamins and minerals. Some of these vitamins are not directly involved in red

blood cell production but they promote the absorption of other important minerals, example

ascorbic acid promotes the absorption of iron from the small intestine.

In Anambra State, most staple foods are consumed without vegetables especially

during the dry season. There are many wild vegetables and fruits wasting in forest. Uzo

(1989) reported that such vegetables as Geotum Africana (“Okazi”), Pterocarpas milbreadi

(“ora”), Pterocarp sp (“Uturukpa”) grow wild. There are many fruits and tender leaves of the

wild vegetables that are readily available in the forest and farmlands during the dry season.

They could be utilized to provide protein and micronutrient needs of the populace. In

Ayamelum local government area of Anambra State, many leafy vegetables and fruits are

grown wildly and there has been little or no work on their nutrient composition.

Documentation of the nutrient potentials of these wild fresh fruits and vegetables would be

valuable in the food-based approach to eliminating micronutrient deficiencies.

1.2 Statement of the problem

There are many wild fruits and vegetables in Ayamelum local government area of

Anambra State which were popular in the past but are no longer popular in the present time.

The fruits and vegetables are not owned by a particular individual, they could be collected

freely and consumed by the populace to increase nutrient intake. Some of the wild vegetables

are available during dry season when many domestic fruits and vegetables are scare and very

expensive. Thus, they could fill the gap experienced in vegetable consumption in rural

community during dry season. Despite the abundance of these fruits and vegetables, there is

still problem of micronutrient deficiency in Nigeria. There is need to identify and evaluate the

nutrient, antinutrients and food toxicant levels of some of the wild vegetables and fruits. The

fruits and vegetables could be integrated in the food-based approach for fighting

micronutrient deficiency in Nigeria.

3

1.3 Objectives of the study

The general objective of the study is to determine the nutrient, antinutrients and

toxicant levels of lesser-known wild fruits and vegetables consumed in Ayamelum local

government area. The specific objectives were to,

(i) identify some wild fruits and vegetables consumed in Ayamelum local

government area;

(ii) determine the proximate, minerals and vitamins levels of the wild fruits and

vegetables identified; and.

(iii) determine the antinutrients and food toxicant (phytate, oxalate, tannins and

saponins) levels of the wild fruits and vegetables identified.

1.4 Significance of the study

The study will directly benefit the inhabitants of Ayamelum local government. This is

because fruits and vegetables to be identified and analyzed are already available in their

locality. They could be sensitized to the availability of the fruits and vegetables for

integration in their dietary plan. The study will provide base-line information on the nutrient

and antinutrient composition of the wild fruits and vegetables found in Ayamelum local

government area. The information will be of use to Dieticians, Nutritionists and Home

Economic Extension Staff in their nutrition Education programme to popularize the fruits and

vegetables. The study will assist help in the estimation of dietary requirement of the fruits and

vegetables. The accurate information on the nutrient and antinutrients composition of these

fruits and vegetables will also help to integrate them in the food based approach for fighting

micronutrients deficiency.

4

CHAPTER TWO

2.0

LITERATURE REVIEW

2.1 Micronutrients

Calcium: Calcium is one of most minerals found in the human body. The teeth and

bones contain most of calcium (about 99%). Nerve cells, body tissues, blood and other body

fluids contain the remaining calcium.(Hamrick and Count, 2002). Calcium helps in

maintaining healthy bone and teeth. Proper levels of calcium over a lifetime can prevent

osteoporosis. Calcium assists in blood clotting, nerve signaling, muscle contraction and

relaxation, and the release of certain hormones. It is also needed for normal heart beat.

Calcium is one of the minerals believed to be an important factor governing fruit storage

quality (Lech et al., 2005). It has been reported to delay ripening senescence and reduce

storage disorder in fruits (Fergusan, 1984).

Institute of Medicine (IOM) (1997) reported the following to be daily dietary intake

of calcium, 210mg-270mg for infants, 500mg-1,300mg for children, 1,300mg for male and

female adolescents (14-18years), 1000mg for adults males and females 19 to 50 years.

Phosphorus: Phosphorus is a mineral that makes up 1% of a person‟s total body weight,

(IOM, 1997). It is present in every cell of the body but most of the phosphorus in the body is

found in bone and teeth. Phosphorus is needed in the formation of bone and teeth. It plays a

vital role in the body in the utilization of carbohydrates and fats and in the synthesis of

protein or the growth, maintenance and repair of tissue. It is crucial for the production of

ATP, a mode to store energy in the body.

Phosphorus works with vitamin D, assists in the contraction of muscles, in the

functioning of kidneys, in maintaining the regularity of the heat beat, and in nerve conduction

(IOM, 1997).They reported the recommended dietary intakes of phosphorus to be 700mg/day

for adults, 1,250mg per day for pregnant and lactating women who are younger than 18 years,

5

500mg per day for children who are between four to five years, 275mg per day for children

who are 7 to 12 months, 100mg per day for children birth to 6 months old.

Iron: Iron is an essential nutrient. Iron occurs in two forms in foods, heme („organic‟) and

non-heme („inorganic‟).The body require iron for the oxygen synthesis, transport of proteins

heamoglobin and myoglobin, and other iron containing enzymes which participate in electron

transfer oxidation –reduction reactions (IOM, 2000).They recommended the following daily

dietary intake of iron, 10mg for adults males, 18mg for adolescents 11years and above, 6-

10mg for infants, 15mg for six months to three years old,

Zinc: Zinc is needed for the body‟s defensive system (immune) to work properly. It plays a

role in cell division, cell growth, wound healing and break down of carbohydrates. Zinc is

also needed for senses of smell and taste (IOM, 2000). The following recommended daily

dietary intake were given by (IOM, 200), 2mg for infants 0-6 months, 3mg for infants 7-12

months, 3mg for children 1-3 years, 5mg for children 4-8 years, 8mg for children 9- 13 years,

11mg for male adolescents and adults 14 years and over, 9mg for female adolescents and

adults 14- 18 years, 8mg for female adolescents and adults 19 years and over.

Iodine: Iodine is a trace mineral and an essential nutrient found naturally in the body. Iodine

is needed for normal metabolism of cells. Human needs iodine for production of thyroid

hormones.

Vitamin A: Vitamin A occur in forms. The first is retinol, vitamin A from animal sources,

another one is carotenes, a yellow pigment found in fruits and vegetables (Leslie and Lendal,

1989). They stated that carotene is not absorbed or utilized as efficiently as retinol, but it is an

important source. Vitamin A is essential for maintaining healthy eyes and preventing

nightblidness. Vitamin A is involved in bone and teeth development. Vitamin A keeps the

6

tissue linings of the respiratory, digestive and urogenital tracts healthy. Vitamin A is also

necessary for healthy skin.

2.2 Importance of fruits and vegetables in diet

Fruits and vegetables are highly beneficial in human diet. The main physiological action of

fruits and vegetables are as follows:

(i)Hydrating effect

Fruits and fruit juice, vegetables and vegetable juice are the most pleasant way of hydrating

the organism (Getahum, 1994). The water absorbed by sick person in this manner has added

advantage of supplying sugar and minerals at the same time.

(ii)Diuretic effect

Clinical observations have showed that potassium, magnesium and sodium contents of fruits

and vegetables act as diuretic. The diuretic frequency of the urination is considerably

increased when fruits and vegetable juice are taken (MacGee and Harold, 2004). They lower

the urine density and thereby accelerate the elimination of nitrogenous waste and chloride.

The diuretic effect of vegetables like potatoes, beans, spinach, radish, turnip are specially

important in cases of edema or swellings, kidney and heart conditions (Getahum, 1974).

(iii)Alkalinizing effect

The organic acids of the salts in fruits and vegetables provide alkaline carbonates when

transformed within the organism, which alkalize the fluids. All the fruits and leafy vegetables

promote intestinal elimination. This keep the body free from toxic wastes, which creep into

blood system from an overloaded, sluggish intestinal tract. Fibre in vegetables act as

mechanical intestinal expanders, draws more water and protein in them. Carbohydrates of

vegetables are chiefly in the form of sugar, dextrin and acids, which are easily digestible and

are completely absorbed. On account of this, they are very useful for sick and invalids for

quick energy and heat. Fibres inform of cellulose help, elimination of cholesterol. Fibre

7

lowers serum cholesterol by reducing the absorption of dietary cholesterol. Fibre complex

with bile acids, which are compounds manufactured by the liver from cholesterol that are

necessary for the proper digestion of fat. After complexing with bile acids, the components

are removed from circulation and do not make it back to the liver as a result the liver must

use additional cholesterol to make new bile. Bile acids are necessary for normal digestion of

fat, American Dietetic Association (ADA, 1997).

2.3 Mineralizing effect

Fruit furnish minerals to the body. Some are rich in calcium and iron. These minerals

are essentials for strong bone and teeth, respectively (Adam and Wiles, 2004). Two important

minerals, calcium and iron, found in vegetables are specially useful, calcium is for strong

bone and teeth, iron is needed for blood formation and an essential constituent of hemoglobin

(Okigbo, 1990).

2.4 Laxative effect

Cellulose, the fibrous matter in fruit and vegetables, aids in the smooth passage of

food in the digestive tract and easy bowel action. The sugar and organic acids contained in

fruits also increase their laxative effect. Hence, regular use of fruits and vegetables prevent

and cure constipation (Jannic, 1990). He stated that certain types of fibre are referred to as

fermentable because they are fermented by the “friendly” bacteria that live in the large

intestine. The fermented dietary fibre in the large intestine produces a short-chain fatty acid

called butyric acid which serves as the primary fuel for the cells in the large intestine and

help in maintaining the health and integrity of the colon. Fibre that are not fermentable in the

large intestine help maintain bowel regularity by increasing the bulk of the faeces and

decreasing the transit time of faecal matter through the intestine. Bowel regularity is

associated with a decreased risk for colon cancer and hemorrhoids when the hemorrhoids are

related to screening and constipation.

8

Tonic action: Fruit and vegetables are dependable sources of vitamins, exert a tonic effect in

the body (Farrell, 1999).Guava, apples and citrus fruits, like lemons and oranges, are

particularly valuable sources of vitamin C. These fruits are usually eaten raw and fresh, thus

making the vitamins fully available to the body. Several fruits contain good amounts of

carotene which gets converted to vitamin A in the body. He further stated that a medium-

sized mango can provide as much as 15,000 international units of vitamin A which is

sufficient for full one week and this vitamin can be stored in the body, Common papaya is an

excellent source of vitamin A and carotene.

Fruit cure: Fruits are highly beneficial in maintaining acid-alkaline balance in the body.

They neutralize the toxic condition of the body resulting from excessive intake of acid-

forming foods and restore its alkalinity (Farrell, 1999). They clear the system of morbid

waste and cater to the body‟s requirement of natural sugar, vitamins and minerals.

Vitamins, minerals, enzymes and trace elements contained in fresh fruits juices are

extremely beneficial in normalizing all the body processes. They supply needed elements

for the body‟s own healing activity and cell regeneration and speed up the recovery.

2.5 Vegetables

Vegetables are edible parts of plants, which are usually cooked or salted prior to

consumption. Vegetables are important protective food for the maintenance of health and

prevention of diseases they contain valuable food nutrients which can be successfully utilized

and repair the body (Enwere, 1998). There are different kinds of vegetables. They may be

edible leafy vegetables for examples lettuce, stem vegetables (asparagus), root vegetables

(carrot), flower vegetables (broccoli) and bulbs (garlic). There are botanical fruits such as

cucumbers and pumpkins as well as legumes such as green, beans and fleshy immature seeds

such as those of peas or beans. They may be cultivated or wild, may be trees, herbs, shrubs or

9

erect plants that cut across the plant kingdom. Certain fruits such as tomatoes and beans are

used as vegetables (Enwere, 1998).

2.5.1 Leaves of the annual and shrubs

Although accurate statistics on the production these leaves are unavailable, data from

several food intake studies (Oguntona et al., 1989; Addo and Eka, 1982) indicate that leaves

of annuals and shrubs constitute the bulk of green leafy vegetables consumed in Nigeria. In

general, however, these are cultivated plants that grow fairly rapidly and are harvested within

weeks of cultivation.

2.5.2 Leaves of trees

If the statistics on production and utilization of leaves of annuals and shrubs are

scarce, those on use of tree leaves as vegetables are much more scarce (Oguntona, 1998).

This is because trees are generally considered important only as source of fruits rather than

leaves for human consumption. Several communities in Nigeria utilize the leaves of many

shrubs and trees. They constitute the group usually referred to as „„lesser- known‟‟ (Temple,

1998).

2.6 Green leafy vegetables

Green leafy vegetables constitute an indispensible constituent of human diet in Africa,

generally and West Africa in particular (Oguntona, 1986). Generally they are consumed as

cooked complements of major staples like cassava, cocoyam, guinea corn, yam, maize,

millet, rice, unripe plantain and banana. Indeed, most of the meals based on these staples are

considered incomplete without a generous serving of cooked vegetables.

The variety of green leafy vegetables utilized are as diverse as both the staples, they

are used in Nigeria alone (Okoli et al., 1988). These range from leaves of annual and shrubs

of the consumed within the localities. There are over sixty species of green leafy vegetables

that are (Amaranthecea, Composite, Portulaceae and Solanacea) to leaves of trees. Many of

10

these leafy vegetables (eg Amaranth) are common in all parts of Nigeria. However, some are

restricted to their natural distribution and mostly found in northern Nigeria. The seasonal

variation affects the availability of these green leafy vegetables. These vegetables grow

abundantly in rainy season when they are much more readily available than in the dry season.

This is particularly true of the annual. Seasonal variation in production and availability

naturally decide the quantities to be consumed by the local consumers.

2.7 Nutrient composition of green leafy vegetables

Green leafy vegetables are good sources of micronutrients (Rajyalashms, 2001; FAO,

1997). There are a lot of green leafy vegetables in Nigeria ecosystem. These could provide

adequate quantities of micronutrient in the diet. In spite of these, Nigerians still suffer from

micronutrient deficiencies (OMNI and USAID, 1993; NDHS, 1990).

Green leafy vegetables consumed in Nigeria have been the subject of many analytical

studies, especially during the 1970‟s (Oke, 1967; Oke, 1968; Fafunso and Bassir, 1977; Ifon

and Bassir, 1979). The nutrient composition of tropical green leafy vegetables and other

groups of tropical foods are available, an excellent compilation (West et al., 1988) exists for

food commonly consumed in East Africa, However, information on green leafy vegetables is

not extensive. Oguntona (1998) reported that the wide variation in nutrient content of green

leafy vegetables are due to (a) a problem of taxonomy or proper identification of samples,

especially given the ever increasing range of strains and hybrids available, (b) variation in the

nutrient and fertilizer status of the soil in which the crop is grown, sample preparation

procedures prior to analysis cause considerable problem and (c) analytical procedures vary in

techniques and quality (Oguntona, 1998).

2.8 Composition and nutritional quality of vegetables

Vegetables contain non-volatile acids, organic acids, mineral salts, volatile sulphur

compounds and tannin, which impart flavour in diets. The colours of vegetables depend on

11

the pigments they contain. Arthocyanin imparts purple and red to vegetables such as reddish

and red cabbage Chlorophyll colours vegetables green, especially leafy ones, green beans

and cucumber while carotenoids are responsible for the yellow colour of ripe tomatoes,

carrots, sweet potatoes and maize (Uwaegbute, 1989).

2.8.1 Carbohydrate: The carbohydrates in vegetables consist mainly of indigestible fibrous

materials such as cellulose, hemicelluloses and lignin. These are in addition to small

quantities of sugars such as glucose, fructose and sucrose. However, the proportion of fibre in

vegetables depends on stages of maturity. (Ifon and Bassir 1989 Uwegbute, 1989).

Carbohydrates are the main component of fruits and vegetables and represent more than 90%

of their dry matter. From an energy point, carbohydrate represents the most valuable of the

food components. Daily adult intake should contain about 500g carbohydrate (Kurczek,

2005). Carbohydrate plays a major role in biological system and in foods,

2.8.2 Moisture: Green leafy vegetables are high in moisture that ranges from 72% in cassava

leaves to 92.93% in India spinach and waterleaf. The turgidity or rigidity of vegetables

depends on the water content. The amount of individual sample depends on several factors

including (a) age (b) agronomic practices prevailing during cultivation and (c) freshness

(Oguntana, 1988). Freshness is a function of time between harvest and analysis as well as the

condition under which the samples are kept during time lag.

2.8.3 Energy: Green leafy vegetables are not good sources of dietary energy. This is a

reflection of low dry matter (DM) content of many of these leaves (Oguntana, 1998)

2.8.4 Protein: Fresh green leafy vegetables have crude protein content ranging from 1.5 to

1.7%. However, Aletor and Adeogun, (1995) however, reported that a mean of 4.2% for

seventeen of such vegetables, when dried samples were used , crude protein range from 15.0

to 30%. Shmidt, (1971) indicated that 75% of total nitrogen in most vegetables were protein.

12

Many reports indicated that leafy vegetable protein is low in sulphur amino acids (Oguntona,

1998).

2.8.5 Ether extract: Leafy vegetables are low in fat and none contain cholesterol (Okigbo,

1977). Among the proximate component, fat content is lowest. The level of ether extract

scarcely exceeds 1.0% in fresh leafy vegetables.(Oguntona, 1998)

2.8.6 Mineral composition: The amount of minerals contained in fruits and vegetables

depend on variety, climate, cultivation and soil type (Teny, Pawn, Mathew and Barrett,1997).

This is the reason for the reported wide variation in some of the published data for green

leafy vegetables in the study of twelve Nigerian vegetables(Oguntona, 1998). Latande and

Dada (1990) reported that the total iron content differed significantly. It ranged from 29.4 to

92mg|kg.

Most of the earlier studies (Oke, 1968: Oyenuga, 1968) showed that Nigerian green

leafy vegetables contain appreciable amount of minerals. This was confirmed by more recent

studies (Ifon and Bassir, 1979; Faboya, 1983; Aletor and Adegun, 1995)

2.9 Vitamins in vegetables

As with other nutrients many factors influence the composition of vitamins in green

leafy vegetables. Cultivars and maturity are important factors as well as light. It is known that

crops mature during autumn contain high pro-vitamin A precursor than those that mature in

poorer light of winter (Selman, 1994).

Many vegetables contain a substance known as carotene, which is converted to

vitamin A. Green leafy vegetables are good sources of ascorbate (Oguntona, 1998). Plants

contain its vitaminA precursor, beta-carotene. Beta-carotene is found in orange and yellow

vegetables as well as green leafy vegetables. Vitamin C is contained in good amounts in

several vegetables such as tomatoes and leafy vegetables such as spinach, cabbage. Fresh

13

vegetables are better sources of vitamin C. Green leafy vegetables are good sources of

micronutrients (Raiylakshims, 2001 and F.A.O., 1997).There are a lot of leafy vegetables in

Nigeria. These could provide adequate micronutrients in the diet when properly processed

and utilized.

2.10 Antinutrient content of green leafy vegetable

The major antinutrients commonly found in green leafy vegetables are phytic and

oxalic acids. These are important because of their significant adverse effect on nutritional

value of these vegetables (Oguntona 1998). High levels of either phytate and oxalate inhibit

the absorption and utilization of minerals in animal and man (Osagie,1998).

2.10.1 Phytate: Phytate is an important storage form of phosphorus in plants. It is insoluble

and cannot be absorbed in the intestine (Osagie, 1998). Phytate has 12 replaceable hydrogen

atoms which it could form insoluble salts with metals such as calcium, iron, zinc, and

magnesium. The formation of these insoluble salts renders the metals unavailable for

absorption. Phytate can also affect availability by chelating with calcium or by binding with

substrate or protolytic enzymes. Heaney, Weaver, Fitzsimmons, (1991) reported that calcium

absorption increases with low phytate (3.01mg/g).

2.10.2 Oxalate: These are naturally occurring substance found in plants, and in humans. In

chemical terms oxalate belong to a group of molecules called organic acids and are routinely

made by plants and humans. Our bodies always contain oxalate, and our cells routinely

convert other substances into oxalates. For example, vitamin is one of the substances that our

cells convert into oxalates. In addition to the oxalates that are made inside the body, oxalates

can enter at our body from the outside from certain foods that contain them (Sienera, 2006).

14

Parivar, Low, and Stoller (1991) observed that low oxalate content foods have less

than 2mg per serving and moderate oxalate food has from 2-10mg per serving and should be

limited to 2-3 serving per day.

2.10.3 Tannins: Tannins are astringent, bitter plant polyphenols that either binds and

precipitate shrink proteins and various other organic compounds. The astringency from the

tannins is what cause the puckrey feeling in the mouth following the consumption of

unripened fruits or red wine (MacGee, 2004). Tannins have traditionally been considered

antinutritional but it is now known that their beneficial or antinutritional properties depend

upon their chemical structure or dosage. Studies have demonstrated that products containing

chestnut tannins included at low dosage in diet (0.15-0.2%) can be beneficial (Schiavone, et

al., 2008)

If ingested in excessive quantities, tannins inhibit the absorption of minerals such as

iron which may if prolonged, lead to anemia (Brien, Rossander, Hallberg, 1989).This because

tannins are metal ion chelators, and tannins chelated metal ions are not bioavailable. Tannins

have been shown to precipitate protein (Bate-Smith and Swain, 1962). Tannins do not affect

absorption of either trace minerals such as zinc, copper, and manganese in rats (Afsanak,

Shiga, Ishizka, Hara, 2003).Large quantity of tannins may cause bowel irritation, kidney

irritation, liver damage, irritation of the stomach and gastrointestinal pain.

2.10.4 Saponins: Saponins are steroid or treerperoid glycosides which are characterized by

their bitter or astringent tastes, foaming properties and their hemolyptic effect on red blood

cells They are widely distributed in the plant kingdom being found in over 500 genera

(Nandy,1991; Birk and Peri, 1980). Saponins have been shown to posses beneficial

(cholesteole lowering, and deleterious (cytotoxic, permeabilization of the intestine) properties

and to exhibit structure dependent biological activities (Peri et al., 1987; Oarkenful and

Sidhum 1989).

15

There are suggestions that the consumption of saponins should be encouraged because

of their nutritional importance. Forage saponins have been reported by Ceake et al., (1978) to

cause toxic and anorexic effects in rats and swine thereby limiting the feeding value of high

animals‟ feeds such as alfalfa. Cassidy and Dalaise, (2003) reported 146mg of saponin to be

safe level, this implies that saponin levels above 146mg is toxic.

2.11 Some commonly consumed vegetables in Nigeria.

2.11.1 Fluted pumpkin: (Telferia occidentails)

The leaves of this crop are important food vegetables for many people, especially in

the mid-western parts of Nigeria. The local names include “Ugu‟‟ (Igbo and “Iroko‟‟

Yoruba).The crop is a member of Cucubitaceae family. It is a perennial vine its stem is as

long as 10 meters. The male plant produces leaves that are similar to the female plants. It has

been estimated that approximately 0.5 kg leaves and hoots are obtained from one plant per

harvest (Tindall, 1983) and up to 15 harvests are obtained between 3-4 months. The leaves

are highly cherished as cooked vegetables and the seeds are used in soups.etc.

The leaf was found to contain in (g/100) 30.5% dry weight, 2.5% crude protein, 3.0 ±

0.15% crude lipid, 8.3 ± 0.50% crude fiber and 8.4 ± 0.50% total ash. The potassium,

calcium, magnesium and iron contents of ash were 594,144, 100 and 120mg/100g dry net

respectively. The leaf was found to contain high level of tannic acid but the levels of phytic

acid and oxalate were within the normal range (Food chemistry, 1985).

2.11.2 Water leave: Water leaf vegetables are rich sources of vitamins A, C and minerals

such as iron, calcium, phosphorus, sodium, potassium and many other carotene content of

water leaf vegetables varied from ponnanganni greens to water convolvulus, vitamin C from

17 ponnanganni green) to 247mg (checkurmanis) and iron from 0.9 (water leaf) to 34.8mg

(water convolvulus) per 100g edible portion phytochemicals were oxalate, saponin, tannin

and phytate and alkaloid.

16

Water leaves have great nutritional value. They contain very high amount of zinc,

important in many enzyme functions and keeping the skin fresh. They also contain saponins

and tannin (glycosides), as well as alkaloids. At least 13 other new compounds or vital

ingredients have been found in these leaves after a 40 years of study, and have the following

benefits, anti-malaria, anti-bacteria, anti-parasites, anti-cancer, scurvy sciatica and

reheumatism. Bitter leaf has high protein (33.3%) fat (2.1%), crude fiber (29.2%), ash

(11.7%), minerals (sodium, calcium, magnesium, zinc and iron, phytate (10.54mg/100g) and

tannin (0.6%) content, and it contains low cyanide (1.1mg/kg).(Food chemistry, 1995)

Table2: Nutrients composition of commonly used fresh green vegetables in Nigeria (per

100g)

Vegetables Moisture Carbohydrate Protein Fat Fibre Ash

Amaranth

Aramanthus

hybridus

84 7.0 4.6 0.2 1.8 2.9

Bitter leaf

mygdaluina

21.6 64.4 22.2 2.7 10.9 10.00

Indian spinach

Basella alba

93.4 2.9 1.6 0.3 0.6 11.00

Water leaf

Trangulane

90.8 4.4 2.4 0.4 1.4 2.00

Fluted

pumpkin

Telfera

occidentalis

86.0 Trace 4.3 0.8 2.3 6.00

Source: Oguntona (1988)

17

Table 2: 2: vitamin composition of commonly used green leafy vegetables (mg/100g)

Vegetables Ascorbate B-carotene

Amaranth 40.5(a)

Bitter leaf, Vernonia amygdalina 34.5(a)

Indian spinach, Basella alba 62(a)

Water leaf ,Talinum triangulane 280(a)

672, (b)

Fluted pumpkin Telfere occidentalis 340(a)

Sources: (a) Oguntona (1988), (b) Pamploma -Rogers (2006)

2.12 Fruits

The term fruits have different meaning. Botanically, a fruit is the ripened ovary

together with seeds of a flowering plant. In many species, the fruit incorporates the ripened

ovary and surrounding tissues. Fruit are the means by which flowering plant disseminate

seeds (Lewis ,2002), in cuisine fruits that are sweet and fleshy, examples of which include

apple and orange (MacGee, and Harold, 2004). However a great many common fruits as well

as nuts and grins are the fruit of the plant species they come from (MacGee and

Harold,2004). Majority of the fruit are fleshly or juicy (Umoh, 1995).

2.13 Nutrient composition of fruits

Fruits are found to be rich in vitamins, especially vitamin C, minerals, sugar

(Achinewu, 1983; Oguntona, 1991). However, higher values for carbohydrate have been

reported in various fruits (Ose, 1971). The main sugar in fruits are glucose and fructose and

sucrose. Some fruit are low in carbohydrate and consequently low in calorie.

2.13.1 Protein: The protein constituents of fruits are low. They serve as components of

nuclear and cytoplasmic structures that take part in determining and maintaining cellular

organization, including the full components of enzymes involved in the metabolism during

18

growth and maturation of the fruit (Umoh, 1998). He further reported that fruits are low in

nitrogenous components as compared to seeds, leaves and some other plant parts and tissues.

2.13.2 Moisture: The moisture content of fresh fruits at maturity is generally high (Umoh,

1998). Moisture content of fruits determines how fresh the fruits were at harvest, or for how

long they have been stored before analysis ( Sheila,1978).

2.13.3 Fats: Fruits are not good sources of fat and are usually recommended as part of weight

reduction diet (Sheil, 1978; Platt, Umoh and Oke, 1978), reported on the nutritional value and

chemical composition of fruits such as lesser-known fruit and seeds. Their reports showed

that oil fruit and seeds contain oils and fats.

2.13.4 Fiber: Fruits and vegetables as sources of dietary fibre normalizes blood glucose

levels. Fibre slows the rate at which food leaves the stomach and by delaying the absorption

of glucose following a meal. Fibres also increase insulin sensitivity. As a result, high intake

of fiber plays a role in the prevention and treatment of type 2 diabetes. In addition, by

slowing the rate at which food leaves the stomach, fibres promotes a sense of satiety, or

fullness, after a meal, which prevents overeating and weight gain (Lom, 2001).

2.13.5 Minerals: Fruits contain mineral elements in low quantities. Gibson, (1997) reported

that plants tend to concentrate calcium in their leaves and phosphors in the seeds. Fruits, like

dried fruits are rich in calcium and iron (Mauseth and James, 2003).

2.14 Vitamins in fruits

Umoh (1998) stated that the main contribution of fruits and their products to nutrition

is their supply of vitamins most, especially the antiascorbic vitamins (Mopson, 1970). Fruits

and vegetables are the main sources from which primates derive their vitamins. Ascorbic

19

acid alongside with other vitamins performs useful functions in the body. Drugs such as

asprin and the contraceptive pills affect the plasma levels of ascorbic acid (Kilgour, 1987).

Ascorbic acid in the body aids in iron absorption from the intestines. It is required for

connective tissue metabolism especially the scar tissue, bones and teeth. It is also necessary

as an anti-stress and protector against cold, chills and damp. It prevents muscle fatigue and

scurvy. It is thought to be necessary for metabolism of cholesterol, reduces the degree of

formation of carcinogenic nitrosamsin from their preculsors and is required in the

hydrocylation of proline to hydroxyperoline of the collagen in the body.

2.15 Commonly used fruits

2.15.1 Guava: Guava is a rich source of vitamin c. It contains a far higher amount of vitamin

C than most of the imported and local fruits. It contains three to six time more than vitamin C

than in orange, 10-30 times more than bananas and about 10 times more than papaya (USDA,

2001). Most of the vitamins C is concentrated in skin and outer mesocarp, reaching a

maximum green fully mature fruit and declining as the fruit ripens.

Guava is very good source of vitamins, fibres as well as minerals. Being rich in

vitamin c, guava is effective in treating male infertility caused by sperm duping, adhension

and other abnormalities. Guava has been associated with treating of wounds, when applied

externally. Guava has general haemostatic properties and can be used for treating bleeding

nose, gums and minor internal hemorrhaging. Guava helps cures dysentery by inhibiting

microbial growth and removing extra mucus from the intestines. Guava helps the body in

combating free radicals produced during metabolism and aids in preventing age-related

chronic diseases such as alchenimers cataractoid and arthritis. Guava is one of the richest

sources of dietary fibre and thus good for those suffering from constipation. Guava

strengthens bones up the digestive system and even disinfect the same.

Guava having high content roughage no cholesterol and less digestible carbohydrate

20

is good for those trying to lose weight. Guava can improve the texture of skin and helps avoid

skin problems. For this purposes guava can either be eaten raw or wash skin with decoction

of guava leaves is known to bring relief in cough and cold. Research has shown that guava is

pretty effective in preventing cancer and even heart diseases in people.

The present complex carbohydrates and dietary fibres in guava make it effective in

lowering cholesterol and blood sugar levels. The presence of vitamin c and phytoutire

carotenoids, isoffavonoids and polyphenols, in guava has led to it being an effective

antioxidant. Guava has been found to be beneficial to people suffering from the following

ailments: (1) Acidosis, (2) Asthma, (3) Bacterial infections (4) Catarrh (5) Convulsion (6)

Congestion of lungs (7) Epilepsy (8) High blood pressure and (9) Obesity, (10) Oral ulcers

(11) Poor circulation (12) prolonged menstruation (13) scurvy (14) swollen gums and (15)

toothache.

Table 3: Proximate composition of Guava, raw: Psidium guajava

Nutrients Units Value per 100g of edible

portion

Sample count Std error

Proximate Units

Water G 86.10 2

Energy Kcal 51 0

Energy Kj 213 0

Protein G 0.82 1

Total lipid (fat) G 0.60 0

Carbohydrate G 11.88 0

Fiber G 5.4 0

Ash G 0.60 0

Source: USDA (2006)

21

Table 4: Mineral composition of Guava

Minerals Units Value per 100g of

edible portion

sample count Std error

Calcium Mg 20 32 1.971

Iron Mg 0.31 12 0.022

Magnesium Mg 10 12 0.216

Phosphorus Mg 25 33 1.465

Potassium Mg 284 16 16.710

Sodium Mg 3 15 0.417

Zinc Mg 0.23 12 0.047

Copper Mg 0.103 12 0.020

Source: USDA (2006)

Table 5: Vitamin composition of Guava

Vitamins Units Value per 100g of

edible portion


Vitamin C Mg 183.5 112 15.120

Vitamin, A, RE Mcg RE 792 25 285.960

Vitamin I U. IU 79 25 28.596

Source: USDA (2006)

2.15.2 Pineapple: Pineapples nutrients include calcium, potassium, fibre, vitamin. It is low

in fat and cholesterol. It is also a good source of vitamins B1, B6, and fiber. Pineapple is a

digestive and a natural anti-inflammatory fruits. A group of sulfur containing protolytic

enzyme in pineapple aid digestion. Fresh pineapples are rich in bromelain. Bromelain has

demonstrated significant anti-inflammatory conditions such as acute smusitis, sorethroat

22

arthritis and gut and speeding recovery from injuries and surgery. Pineapple should be eaten

alone between meals (USDA, 2001).Pineapple enzymes have been used with success to treat

rheumatoid arthritis and to speed tissue repair as a result of injuries diabetic ulcers and

general surgery. Pineapple reduces blood clotting and helps remove plague from arterial

walls. Studies request that pineapple enzymes may improve circulation in those with

narrowed arthritis such as argina sufferers.

Pineapple are used to help cure bronchitis and throat infections. It is efficient in the

treatment of arteriosclerosis and anemia. Pineapple is an excellent cerebral toner, it combats

loss of memory, sadness and melancholy have exceptional juice and exceptional health

benefits. It is rich in manganese and just one cup of pineapple provide 73% of the daily

recommended amount of manganese. This aids the growth of bones in young people and the

strengthening of bones in older people.

Due to its high vitamin c content, pineapples are good for oral health. Vitamin c can

reduce risk of gingivitis and paridental disease. Vitamin c also increases the body‟s ability to

fight invading bacteria and other toxins that contribute to gum disease. Pineapple has been

thought good for the heart conditions and indeed should not be used by people with

haemophillia or by those with disease of the kidneys and liver. This is because it seems to

reduce the time taken to coagulate the blood – which is why it can be useful for heart

patients.

Pineapple could be useful for women suffering from painful periods. Ripe fruits of

good colour should be chosen. Pineapple are not sweeter on storage if they are picked unripe.

This is because the starch in the stem is taken up into the fruit and converted to sugar only at

the final stage of ripening. Pineapple has been shown to be important in maintaining good eye

health and helping to protect against age-related eye problems. There are even some

beneficial molecules hidden in the stems of pineapple. These molecules haven been seen to

23

act as a defence against certain types of cancer.

Aside from fiber, there are many other essential nutrients. Vitamins that can be found

in pineapple are vitamin and nutrients that can be found in pineapple include vitamin C,

vitamin A, calcium and potassium. It is believed that the best source for these nutrients is

fresh pineapple. Pineapple contains bromelain, which is known to help relieve or even stop

coughs altogether. The main reason is because it is anti-inflammatory and ultimately, it is

known to help with the loosening of mucus.

Table 6: Nutrients composition of Pineapple, raw: (Ananus comosus)


portion


Proximate 86.50 37 0.300

Water g 49 0

Energy kcal 205 0

Energy kj 0.39 17 0.012

Protein g 0.43 15 0.148

Total lipid (fat) g 12.39 0

Fibre, total dietary g 12 0

Ash g 0.29 32 0.010

Source: USDA (2006)

24

Table 7: Mineral content of Pineapple


edible portion



Iron Mg 0.37 15 0.025





Zinc Mg 0.08 15 0.007

Copper Mg 0.110 15 0.009

Source: USDA (2006)

Table 8: Vitamin content of Pineapple


edible portion


Vitamin C Mg 15.4 11 0.550


Vitamin I U. IU 2 22 0.519

Source: USDA. Nutrition database for standard reference, release (14 July, 2006)

2.15.3 Mangoes: Mangoes contain several important phytochemicals including

cryptoxanthin, lutein, galic acid and anacardic acid. Mangoes are an incredibly healthy

snack. The entire fruit can be eaten for just over hundred calories. High in fibre, virtually fat

free and mangoes contain numerous vitamins.

Mangoes contain, B – carotene which may slow the aging process, reduce the risk of

certain forms of cancers, improve lung function, and reduce complications associated with

diabetes. Mangoes are rich in antioxidants such as beta carotene (44.5g/100g fruit) and

25

vitamin C (27.79/100g fruit). Mangoes contain vitamin A (equivalent 38g/100g fruit),

vitamin E. Mangoes also contain vitamin B6, (0.134mg/100g fruit), other vitamins B1and B12.

Mangoes supply nutrients such as potassium (15.6mg/100g fruit), calcium (10mg/100g fruit),

Magnesium (10g), iron (0.12mg) and zinc (0.04mg/100g) and fibre and are low in calories.

Mango peels and pulp also contain carotenoids, polyphenols, and antioxidant. The edible

peel of the mango is a good source of fibre (USDA, 2001). Mango is considered as an

energizer in Ayurved as 100g mango fruit provides about 17.0g carbohydrates.

The fruit is rich in pre-biotic dietary fibre, vitamins, minerals and polyphenol and

flavonoids and antioxidant compounds. Mango is a very good sources of vitamin A and

flavornoid like beta carotene, alphacarotene and beta cryptoxanthin. These compounds are

known to have antioxidant properties and are essential for vision. Vitamin A is also required

for maintaining healthy mucus membranes and skin. Consumption of natural fruits rich in

carotene are known to protect from lung and oral cavity cancers.

Fresh mango is a very rich source of potassium. Potassium is an important

component of cells and body fluids that helps in controls heart rate and blood pressures. It is

also a very good source of vitamin B6 (pyridoxine), vitamin C and copper. Consumption of

food rich in vitamin c helps body develop resistance against infectious agent and scavenge

harmful oxygen free radicals. Copper is a co-factor for many vital enzymes including

cytochrome c-oxidase and superoxide dimutaser. Copper is also required for the production

of red blood cells. Mango peels are also rich in phytonutrient such as the pigment

antioxidants like carotenenoids and polyphenols (USDA, 2001).

26

Table 9: Proximate composition of Mangoes, raw( Mangifera idica)

Nutrients Units Value per 100g` of edible

portion

sample count Std error

Proximate

Water g 81.71 108 0.323

Energy kcal 65 0

Energy kj 272 0

Protein g -0.51 79 0.025

Total lipid (fat) g 0.27 47 0.039

Carbohydrate g 17.00 0

Fiber g 1.8 0

Ash g 0.50 66 0.033

Source: USDA (2006)

Table 10: Mineral composition of Mangoes


edible portion



Iron Mg 0.13 21 0.021





Zinc Mg 0.04 1

Copper Mg 0.110 17 0.009

Source: USDA (2006)

27

Table 13: Vitamin content of mangoes


edible portion


Vitamin C Mg 27.7 162 1.740


Vitamin I U. IU 3894 91 24.417

Source: USDA (2006)

2.15.4 Pawpaw: Pawpaw is very nutritious fruits. They are high in vitamin C, magnesium,

iron, copper and manganese. They are good sources of potassium and several essential amino

acids .They also contain significant amount of riboflavin, niacin, calcium, phosphorus, and

zinc. Pawpaw contain these nutrients in amounts that are generally about the source or greater

than those found in bananas, apples, or oranges (USDA, 2001)

Pawpaw has a higher protein and fat content. Banana exceeds pawpaw in food energy

and Carbohydrate content in pawpaw is most similar in overal composition.

Pawpaw has three times as much vitamin C as apple, twice as orange. Pawpaw has six times

as much as riboflavin as apple, and twice as much as orange. Niacin content of pawpaw is

twice as high as bananas, fourteen times as high as apple and four times as high as orange.

Pawpaw and banana are both high in potassium having about twice as orange and three times

as much as apple. Pawpaw has one and half times as much calcium as orange and about ten

times as much phosphorus, four to twenty times as much iron, five to twenty times as much

zinc five to twelve times as copper, and sixteen to one hundred times as much as manganese,

as do banana, apple or orange.

Protein in pawpaw contains all of the essential amino acids and it exceeds apple in all

amino acids. It exceeds or equals banana and orange in most of them.

28

2.15.5 Orange: Orange like other citrus fruits is known for vitamin C content. Due to this

high amount of vitamin C, orange helps in absorbing calcium into the body and maintaining

the health of teeth and bones. It also contains vitamin A and vitamin B. 100g of orange

contains about 60 calories. This energy is available in form of sugar which can be absorbed

by the body easily. Hence orange juice is often fed to people who have become weak due to

some illness. Orange juice is also a good refresher after a long exhaustive day.

The nutritional value of orange makes good for indigestion constipation, bowel

disorder, dyspeosia, dental care, pyorrhea, bone health, heart diseases, respiratory problems,

cold, cough influenza, skin care, pimples, acne, fever measles, typhoid and tuberculosis

(USDA, 2001).

Table 14: Proximate composition of Orange, raw,( Citrus sinesis)


portion


Proximate

Water g 86.75 88 0.121

Energy kcal 47 0

Energy kj 197 0

Protein g 094 69 0.014

Total lipid (fat) g 0.12 4 0.010


Fiber g 2.4 0

Ash g 0.44 79 0.006

Source: USDA (2001)

29

Table 15: Mineral content of Orange

Minerals Units Value per 100gm of

edible portion


Calcium Mg 40 0

Iron Mg 0.10 64 0.004





Zinc Mg 0.07 3

Copper Mg 0.045 64 0.003

Source: USDA (2006)

Table 16: Vitamin content of Orange


edible portion


Vitamin C Mg 53.2 148 5.890


Vitamin I U. IU 21

Source: USDA (2006)

2.15.6 Avocado: Avocado is a fat-rich fruit, its fat content is about 23%. It contains dietary

fibre. It is rich in minerals such as copper magnesium, manganese and moderate in iron,

calcium, iodine, selenium, zinc and phosphorus. Avocado is well known for its high vitamins

K and A content. It also contains small amount of vitamins B C, vitamin E, thiamin,

riboflavin, niacin, vitamin B6, biotin and folate. Fruits are normally not rich in calories and

are eaten for their ability to provide vitamins, minerals and digestive fibre content. However,

30

avocado owing to its high fat content provides good quantity of calories. A -100g of edible

portion of the fruit provides about 215 calories.The nutritional value of avocado makes it

good for indigestion, hair care, heart health, skin care, psoriasis and bad breath (USDA,

2001).

Table 17: Avocado, raw,( Persea American)


portion

Scruple count Std error

Proximate 0.817

Water G 74.27 58

Energy kcal 161 0

Energy Kj 674 0 0.042

Protein G 1.98 58

Total lipid (fat) G 15.32 54


Fiber g 5.0 0 0.093

Ash g 1.04 57

Source: USDA (2006)

31

Table 18: Mineral content of Avocadoes


edible portion



Iron Mg 1.02 54 0.122




Sodium Mg 10 30 1.146

Zinc Mg 0.42 1

Copper Mg 0.262 54 0.020

Source: USDA (2006)

Table 19: Vitamin content of Avocados


edible portion


Vitamin C Mg 7.9 6 1.528



Source: USDA.(2006)

32

2.15.7 Apple: The health benefits of apple are enormous. These makes it one of the most

valuable and savored fruits throughout the world. Apple contains minerals such as

magnesium, copper, manganese, calcium, iron, potassium and phosphorus in small quantities.

Apple also contains dietary fibre, which helps in reducing the bad cholesterol level.

Apple is rich in vitamin A and C. Vitamin A concentration is higher in the outer skin

than the flesh. Like potatoes, vitamin C concentration is higher just below the skin in apples

also. Based on this the skin should not be discarded. Other vitamins present in apple include

vitamin K, thiamin, riboflavin and B6.

Apple does not have calories as high as avocado or olives. It is an excellent source of

energy. The calorie content varies as per the type of apple. Apple contains sugar which is

easily absorbed by the body. The weak and ill are often advised to eat apples for gaining

weight and fast recovery. The nutritional value of apple makes it useful for digestion,

stomach disorders, anemia, weakness, dental care, dysentery, heart disease, reheumatism, eye

disorders, cancers, gouts, and skin care (USDA, 2001).

2.15.8 Banana: Banana is rich in potassium, it also contains other minerals such as calcium,

iron, magnesium and phosphorus in large quantities. It is rich in fibRE making it useful

laxative and good for easing constipation. Bananas contains about 90 to 93 calorie per 100g.

This energy is easily absorbed by the body. Consumption 3-4 bananas daily, especially with

milk, is often recommended to gain weight, banana is useful for 100mg, weight because it has

only 90 calories per 100g (USDA, 2001). The nutritional value of banana makes it useful for

weight gain as well as weight loss, constipation, bowel problems, anemia, blood pressure,

heart problems, ulcers, brain stimulation, depression, nervous disorders, stress and morning

sickness.

33

Table 20: Proximate composition of Banana, raw (Musa paradisiacal)


portion


Proximate

Water G 74.26 116 0.381

Energy Kcal 92 0

Energy Kj 385 0

Protein G 1.03 111 0.026

Total lipid (fat) G 0.48 11 0.135


Fiber G 2.4 0

Ash G 0.80 110 0.016

Source: USDA (2006)

Table 21: Mineral content of Banana

Minerals Units Value per 100gm of

edible portion



Iron Mg 0.31 108 0.015


Phosphorus Mg 20 102



Zinc Mg 0.16 13 0.008

Copper Mg 1.104 109 0.009

Source: USDA (2006)

34

Table 22: Vitamin content of Banana


edible portion


Vitamin C Mg 9.1 14 0.339



Source: USDA (2006)

Table 23: Proximate content of Pears, raw;( Pyrus communis)


portion


Proximate

Water G 8381 44

Energy Kcal 59 0

Energy Kj 247 0

Protein G 0.39 40 0.021

Total lipid (fat) G 0.40 5 0.121


Fiber G 2.4 0

Ash G 0.28 44 0.008

Source: USDA (2006)

35

Table 24: Mineral content of Pears


edible portion


Calcium Mg 11 6

Iron Mg 0.25 42 0.014





Zinc Mg 0.12 5 0.026

Copper Mg 0.113 45 0.006

Source: USDA (2006)

Table 25: Vitamins A & C composition of commonly used fruits in Nigeria (mg/100g)

Fruits Ascorbate B-carotene

7.90 61.0

Guava Psidum guajava 180 79.0

Orange citrus species 53.2 21.0

Mango, Magnifera indica 27.7 38.9 765 IU

Pineapple Ananas comosus 15.4 1.20

Pawpaw, Carica papapya 61.8 17.5

Source Pamploma-Roger (2006)

36

Table 26: Proximate composition of commonly used fruits in Nigeria (%)

Fruits Moisture Carbohydrate Protein Fat Ash Fiber

Avocado peer 2.39(a)

1.98(a)

5(a)

Guava 6.07(a)

0.82(a)

5.40(a)

Orange, Citrus

species

91(c)

9(a)

0.42(a)

0.12(a)

0.08(c)

2.40(a)

Pineapple

Ananas

cosmosus

94(c)

11.20(a)

0.39(a)

1.20(a)

Pawpaw

Carica papaya

87(c)

8.01(a)

0.6(a)

4.83(c)

1.80

Sources: a = Pumploma – Roger (2006)

b = Umoh (1998)

c = Muncro and Bassir (1969)

37

Table 27: Mineral composition of commonly used fruits in Nigeria (mg/100g)

Fruits Calcium Phosphorus Iron Zinc Copper

Avocado peer 11.0 41.0 1.02 0.42

Guava 20.0 25.0 0.31 0.23

Orange 40.00 46.0 0.10 0.07 0.04

Mango Magrifera

indica

10.0 11.0 0.13 0.04

Pineapple, Ananas

cosmosus

7.00 7.00 0.37 0.08

Pawpaw Carica

papaya

24.00 5.0 0.10 0.07 0.5

Sources: Pamploma – Roger (2006)

38

CHAPTER THREE

3.1 MATERIALS AND METHODS

The fruits and vegetables used in this study were identified and collected from forests

in Ayamelum local government area. Ayamelum local government comprises eight

communities (Omor,Umumbo, Omasi, Ifite-Ogwari, Umueje, Umerum, Igbakwu, and

Anaku)

3.2 Pilot study

3.2.1 Identification of samples

Three men and two women (Ayamelum indigenes) assisted the researcher to collect and

identify some of the wild fruits and vegetables are consumed in the locality. The fruits and

vegetables were collected from forests in two communities (Omor and Umumbo) in

Ayamelum local government area of Anambra State. They identified the wild fruits and

vegetables with their local names. Subsequently the researcher took samples of the fruits and

vegetables to the Department of Botany, University of Nigeria, Nsukka, for characterization

and identification with their botanical names. The result is shown in Table 1.

Table 1: Some wild fruits and vegetables identified for use in Ayamelum local

government area.

Local names Botanical names Common names Parts of the plant

1 “Osenga” Olax viridis - Fruits

2 “Uchakulu” Vitex deniana black plum Leafy vegetable

3 “Akankolo” Ficus carpensis Fig trees in

general

Fruits & vegetable

4 “Aado” Gongronema Sp - Fruits

5 “Ukpodikili” Napoleona imperialis Tree species Fruits

6 “Okwocha” Afromomum Sp Monk‟s or

malaqueta

pepper

Fruits

39

All the fruits and vegetables collected were analyzed fresh for various nutrients and anti

nutrients

Vitex doniana

40

Napoleona imperalis

41

Afromonum specie

42

Ficus carpensis

43

Gongronema sp

44

3.2.2 Preparation of materials

Polyethylene bags were used for collecting and storing of samples to avoid

contamination. The leaves were picked to remove unwanted materials. The leaves and fruits

were washed with iodized water and excessive water was dripped off. Edible portions of the

vegetables and fruits were cut into pieces and homogenized using a blender. The

homogenized samples were transferred into an air tight container. The leaves and fruits were

analyzed fresh.

3.3 Chemical analysis

The samples were weighed to the nearest gram and transferred to the laboratory for

analysis. Each sample was homogenized separately and aliquots were taken from each

sample for moisture analysis. All analysis were done in triplicate. Proximate, mineral,

vitamin, antinutrient and food toxicant composition of the samples were determined using

AOAC (1995) methods.

3.3.1 Fat determination

Fat was estimated by the Soxhlet extraction (AOAC, 1995) procedure

1. Two (2y) grammes of samples were weighed into dry Soxhlet thimbles

2. The thimbles were suspended in a beaker and dried to a constant weight in an oven

and then placed in a soxhlet condenser containing ether.

3. A reflux condenser was attached to the contracted tube and heated, the ether was

returned to the flask with fat when the thimble was full.

4. The extraction was continued for about 6 hours at 120.c

5. The flask and fat were drained in air to vaporiate the ether and weighed to a constant

weight.

6. Fat was washed off with a fat solvent , dried and weighed again.

45

%fat =

Where X1 = initial weight of flask

X2 = final weight of flask

W = weight of samples

3.3.2 Moisture determination

This was done by hot air oven method of Pearson (1976).

1. Two (2a) grammes of samples were weighed into an empty aluminum dish with a

known weight.

2. The dish and samples were dried in an air oven at 1000C for 24 hours and cooled in

dessicator and re-weighed.

3. This process was repeated until weight is obtained.

% Moisture =

Where X = weight of empty dish

Y = initial weight of dish + weight of sample

3.3.3 Ash determination

1. One (1g) of sample was placed in a clean crucible of known weight. The crucible was

placed in a muffle furnace (6000C) over night or 24 hours.

2. The crucible and content were cooled in a dessicator and weighed again

%Ash =

Where X = weight of crucible

Z= weight of crucible and ash

46

3.4 Crude fibre determination

The crude fibre content of the samples were determined by using (AOAC) (1995).method

3.4.1 Method

1. Two (2g) grammes of the sample was placed in a 250ml beaker, boiled for 30 minutes

with a 100ml 0.12 MH2SO4 and filtered through a funnel.

2. The filtrate was washed with boiling water until the washing was no longer acidic.

3. The solution was boiled for another 30 minutes with 100ml of 0.12m sodium

hydroxide solution filtered three times with hot water and methylated spirit.

4. The residue was transferred into a crucible and dried in an oven for 1 hour. The

crucible and its content were cooled in a dessicator, and re-weighed (w2). The crucible

and its contents were taken to a furnace for ashing for 1 hour.

5. The ash sample was removed from the furnace after temperature had cooled and put

into a dessicator and later re weighed (w3). The crude fibre content was obtained

between the weight before and after incineration. The percent of the crude fibre was

calculated thus.

%Crude fibre =

Where W1 = weight of crucible

W2 = initial weight of sample and crucible

W3 = final weight of sample and crucible

100 = percentage

3.5 Crude protein determination

The micro-kjedahl method (AOAC,) (1995) involve digestion, distillation and

titration was used to obtain the crude protein content of the samples.

47

3.5.1 Digestion

1. One (1g) gramms of each sample was weighed into a 100ml Kjeldahl flask.

2. Twenty five (25) grammes of anhydrous sodium sulphate, 05g copper sulphate

(catalyst) and 5ml of concentrated sulphuric acid was added.

3. The flask was placed in fume chamber and heated gently until the solution turns

black, then the heat was cooled, washed and transferred into a 250 volumetric flask

and rinsed down with distilled water.

3.5.2 Distillation

1. A combination of boric acid and methyl red indicator was poured into conical flask

and placed under a condenser in such a way that the condenser tip was under the

liquid.

2. About 5ml of the digest plus 10ml of 60% concentrated sodium hydroxide was placed

in a Markham distillation apparatus.

3. Steam was let down through the distillation apparatus for 5 minutes. Ammonia was

evolved, which changed the color of the indicator from purple to green characteristics

of alkaline gas.

3.5.3 Titration

1. The distillate was titrated with 0.1 hydrochloric acid (HCl) until a neutral point was

reached (faint purple)

2. Titre value (T) = final biuret reading-initial biuret reading.

%Crude protein =

3.6 Carbohydrate determination

This was determined by difference ie. % carbohydrate = 100- (%protein + % fat + fibre + %

ash + % moisture).

48

3.7 Determination of iodine, iron, copper, calcium, zinc and phosphorus

AOAC (1995) wet digestion procedure was used in estimating iron (Fe), iodine, (12),

copper, calcium, zinc and phosphorus.

1. Five millitres (5ml) of perchloric acid and 10ml of neuric acid were heated under

fume chamber until the solution turned colourless and free of nitrogen. One (1g)

gramme of the sample was weighed into a 100ml round bottom flask and diluted into

a known volume before used for absorption spectrophotometer.

2. A spectrometric atomic absorption spectrophotometer was used on a general principle

that minerals are absorbed at different wavelength, Fe (248.30), 12(353.0, Cu(324.70),

Zn(213.90) , Ca(230.0) and P(470)

3. Readings were obtained against standard for each mineral and distilled water was

used to zero the spectrophotometer after each reading. Calibration curve was

constructed for each mineral and used to calculate its concentration.

3.8 Pro-vitamin A (RE) determination

Provitamin A was determined using the method adopted from IVACG (1982). The

vitamin A activity, as retinol equivalent (RE) was calculated based on the vivo concentration

factor (WHO, 1982).

Caratenoids (RS) (U-V-spectrophotometric method

Reagents

Cyclohexane

Carotenoids (RS)

3.8.1 Principle

The principle was based on the use of U-V- spectrophotometric method as ashing

with cyclohexane.

49

3.8.2 Method

The samples or prepared portions were dissolved in cyclohexane such that it contains

9-15 units per ml and obtained the wavelength of maximum absorption. The extinctions at

the wavelength were measured and calculated as fractions relative to that at 328nm. The

Eicm figure was calculated at 328nm if the wavelength of maximum absorption is 326 –

329nm and observed relative extinction was within 0.02.

3.8.3 Calculation

Potency (units 1g) = 1900x E328nm. The following correction was applied if the

maximum lies in the same range, but the relative extinction are not within 0.02 E238

(corrected 3.52(2E328 – E328 – E316 – E340).

3.9 Ascorbic acid determination

AOAC (2005) official methods of analysis was used. Ascorbic acid was determined

by using a dye solution of 2.6 dichophenol, indophenol (4 tablets of dye were dissolved in

little water and transferred to stopered measuring cylinder making volume to 100cm3 and

mixing well and labeled 1cm3 = 0.4mg AA. The quantity of samples was weighed, mashed

and liquidized with 50cm3 dilute acetic acid and transferred to stopered measuring cylinder

and made to 100cm3 .with water. The sample was homogenized, allowed to settle and the

supermatant liquid was decanted off. This was filtered with a muslin cloth and labeled

10cm3. An aliquot was transferred to a small conical flask using a pipette and titrated against

the dye solution to pale pink that pointed persisting for 15 seconds. Ascorbic acid content was

calculated in mg per 100g of sample. If average titration result = Vcm3dye (0.4mg Aacm

3).

100 extract contains V x 0.4 x 100 x100/wmg- AA =40v/wmg AA.

50

3.10 Determination of antinutrients

3.10.1 Phytate

The method described by Latta and Eskin (1980) was adopted. About 0.5g of each

sample was extracted with 100ml of 24% of hydrochloric acid. The diluted extract was

passed through the amberite resin. Inorganic phosphate was eluted with 0.1ml of sodium

chloride and 0.7m sodium chloride. Colour was developed with 1ml of modified Wade

reagent, 0.03% Fecl,6 Hz 0 and 0.3% sulphur salicylic acid. The absorbance was read at

500m in a CE 2343. Digital grading spectrophotometer was made up to mark 25ml 30%

HCL.

3.10.2 Tannins

Tannins was determined by using the spectrophotometric method described by Price

and Butter (1977). About 0.5g of each sample was extracted with 3ml methanol. The extract

was mixed with 5.0ml water 3ml of 1.0ml (Fecl2 in 0.1N and 0.8 ml2 Fe (w2) was added to

0.1ml of the solution. The extract was read at 720nm on a spectrophotometer.

3.10.3 Saponins

About 0.1g of the sample was boiled and filtered with Whatman No.1. Five (5)ml of

the titrate was pipetted into a test tube and 2ml of olive oil was added. The solution was

shaken vigorously

Documents

CHEMICAL COMPOSITION OF SOME LESSER-KNOWN WILD … · PG/M.Sc/03/34109 has satisfactorily completed the project report for the award of Master of Science (M.Sc) degree in Human Nutrition