ABSTRACT
Diallium guineense fruit pulp and leaves popularly consumed raw by some tribes in Nigeria were studied for their proximate, vitamin, mineral and phytochemical composition. The fruit pulp and leaves were respectively found to contain 5.54±0.0.07%, 19.71±0.12% crude protein, 3.14±0.02%, 9.49±0.09% ash, 4.48±0.0%, 12.57±0.24% crude fibre, 2.21±0.04%, 3.43±0.02% crude fat and 71.67±0.03%, 44.58±0.16% carbohydrate respectively. They also contained reasonable amounts of mineral elements which ranged from 42.77±0.09 - 65.59±0.15 mg/100g sodium, 238.67±0.09 - 247.70±1.48 mg/100g potassium, 84.81±0.56 - 175.75±1.62 mg/100g calcium, 264.78±0.68 - 284.60±0.10 mg/100g phosphorus, 2.35±0.02 – 3.65±0.15 mg/100g zinc and 3.14±0.03 – 4.72±0.10 mg/100g iron. They also contained appreciable values of vitamins A (86.68±0.1.08 – 42.77±0.09 IU/100 g), Vitamin C (254.78±0.49 – 254.35±8.50 mg/100g) and Vitamin E (2.78±0.02 – 3.52±0.10 mg/100g). The phytochemical/antinutrient contents were low. They were however high in nitrate (19.62±0.24 – 34.71±0.12 mg/100g) and nitrite (4.64±0.03 – 7.52±0.08 mg/100g). Except for moisture, carbohydrates and magnesium, the leaf sample was found to have higher values of all the nutrients considered. Both the fruit pulp and leaves of Diallium guineense were found to be rich in nutrient composition and can therefore be recommended to serve as a food supplement or snack for consumers as a means of meeting part of their daily nutritional needs. The GC-MS analysis of the methanol extract of the fruit pulp revealed the presence of thirty one components.
TABLE OF CONTENTS
Title Page i
Declaration ii
Certification iii
Dedication iv
Acknowledgements v
Table of Contents vi
List of Tables viii
List of plates ix
Abstract x
CHAPTER
1 INTRODUCTION
1.1 Background of Study 1
1.2 Fruits 2
1.3 Classification of Fruits 4
1.4 Nutritional
Composition of Fruits 5
1.4.1 Vitamins 5
1.4.2 Carbohydrate 5
1.4.3 Protein 6
1.4.4 Fat 6
1.4.5 Fiber 6
1.4.6 Moisture 6
1.5 Phytochemical/Anti-Nutrient 7
1.5.1 Phytate 7
1.5.2 Oxalates 7
1.5.3 Tannins 8
1.5.4 Saponins 8
1.6 Antioxidant and
Antimicrobial 9
1.7 Importance
of Fruits and Vegetables in Diet 10
1.7.1 Hydrating
Effect 10
1.7.2 Diuretic Effect 10
1.7.3 Alkalinizing Effect 11
1.7.4 Mineralizing Effect 11
1.7.5 Laxative Effect 11
1.7.6 Tonic Action 12
1.7.7 Fruit Cure 12
1.8 Important Health Benefit
of Fruit 13
1.9 Wild Fruit Trees 13
1.10 Overview of Diallium Guineense 15
1.10.1 Properties of the
Specie 16
1.11 Uses and Product 16
1.12 Industrial Uses 17
1.13 Statement of the Problem 17
1.14 Preservation/Storage of Di allium
Guineense Products 18
1.15 Aim and Objectives
of the Study 19
CHAPTER
TWO: LITERATURE REVIEW 20
CHAPTER
3: MATERIALS AND METHOD
3.1 Sample collection 23
3.2 Sample Preparation 23
3.3 Analysis of
Samples 24
3.3.1 Moisture Content 24
3.3.2 Ash Content 24
3.3.3 Determination of Crude Fibre 25
3.3.4 Determination of Fat Content 25
3.3.5 Determination of Crude Protein 26
3.3.6 Determination of Carbohydrate Content 27
3.4 Determination of
Vitamins 27
3.4.1 Determination of Vitamin A 27
3.4.2 Determination of
Vitamin B1 (thiamine) 28
3.4.3 Determination of
Vitamin B2 (riboflavin) 29
3.4.4 Determination of
Vitamin B3 (niacin) 30
3.4.5 Determination of
Vitamin B6 30
3.4.6 Determination of Vitamin C (ascorbic acid) 31
3.4.7 Determination of Vitamin E 32
3.5 Phytochemical
Determination 33
3.5.1 Determination of
Alkaloids 33
3.5.2 Determination of Flavonoids 33
3.5.3 5Determination of
Saponins 34
3.5.4 Determination of Tannins 34
3.6 Determination of Anti-Nutrients 35
3.6.1 Determination of Oxalate 35
3.6.2 Determination of
Phytate 36
3.6.3 Cyanide Analysis 37
3.6.4 Determination of Phenol 38
3.7 Determination of
Minerals 38
3.7.1 Determination of
Calcium and Magnesium 38
3.7.2 Determination of Potassium and Sodium 39
3.7.3 Determination of
Phosphorus. 41
3.8 Determination of
Heavy Metals 41
3.9 GC- MS Analysis 43
CHAPTER
FOU4: RESULTS AND DISCUSSION
4.1 proximate
composition of diallium guineense 44
4.2 Mineral
Composition of Diallium Guineensepulp
and Leaves 51
4.3 Vitamin
Composition of Diallium Guineense 58
4.4 Phytochemical
Compositions of Diallium Guineense Fruit
Pulp and Leaves 62
4.5 Top of Form
GC-MS Analysis of Diallium
Guineense Fruit Pulp 67
CHAPTER 5: CONCLUSION
AND RECOMMENDATIONS
5.1 Conclusion 76
5.2 Recommendations 76
REFERENCES
LIST OF TABLES
4.1: Proximate
composition of Diallium guineense 45
4.2: Result of proximate composition of Diallium guineense pulp and leave
compared
to reported values. 48
4.3: Result of proximate composition of Diallium guineense pulp and leave
compared
to reported values (%) of commonly used fruits in Nigeria (%) 50
4.4: Mineral
composition of Diallium guineensePulp
and Leaves 52
4.5: Comparism of mineral contents of Diallium guineense fruit and leave and
other
commonly used fruits in Nigeria 57
4.6: Vitamin
composition of Diallium guineense fruit
pulp and leaves 59
4.7: Vitamin
composition of Diallium guineense
fruit and leave compared with
reported
values for other fruits 61
4.8: The phytochemical contents of Diallium guineense fruit and leave 63Top of
Form
4.9: Phytochemical content of Diallium guineense
fruit and leaves in the
Present
work compared to reported values for Diallium guineense fruit pulp 66
4.10: GC-MS analysis result of Diallium guineense fruit pulp 68
4.11: Medicinal Uses of some of the compounds
isolated from the fruit pulp 69
LIST OF PLATES
2.1 Fruit pulp Diallium guineense 15
3.2 Diallium
guineense fruit pulp and leaf samples, for analysis 23
CHAPTER
1
INTRODUCTION
1.1 BACKGROUND OF STUDY
Over
the years, regulatory bodies such as Food and Agriculture Organization (FAO)
has reported that the average standard nutritional intake in developing
countries such as Nigeriais generally low, csalling for concerted efforts
towards alleviating this crisis of nutrient deficiencies. Since then, a lot of
researches have been directed toward determination of nutrient composition of
other traditional foods that will be affordable to supplement the limited
conventional ones. Tomas-Barberan and Gil (2008) posited that there is substantial
andgrowing evidence showing that increasing fruits and vegetables
consumptionreduce the risk of chronic diseases and increases lifespan and
quality of life, whiledecreasing medical costs. However, there has been a
growing reduction in the consumption of vegetables with each passing decade
(Aranceta, 2004). The affluence in recent decades has made humans to focus on
relatively fewer plant foods and placing humans at risk. The World Health
Organization (WHO) (1995) and Food and Nutrition Research Institute (FNRI)
(2000) observed that the problem with the urban populace was not of energy but
overweight. It observed that they consumed carbohydrate-richfoods, which were
mainly purchased as refined foods. Consequently, several researchers (Ifeanacho,2009)
had posited that in no other class of food is the beauty of nature made
manifest than in fruits.
Sources
of food nutrients can be broadly divided into two; namely those of animal
origin such as meat, milk, egg, blood etc and those of plant origin such as
vegetables, fruits, seeds, nuts, oilsetc. Fruits and leaves of plants have been
found to be highly nutritious especially of vitamins and other essential (micro
and macro) nutrients.They also vary greatly in their content of energy and
nutrients. Additionally, fruits and vegetables supply dietary fiber. Fiber
intake is linked to lower incidence of cardiovascular disease and obesity. Fruits
and vegetables also supply vitamins and minerals to the diet and are sources of
phytochemicals that function as antioxidants, phytoestrogens and anti-inflammatory
agents through other protective mechanisms. They are also recommended as a
source of vitamin C and potassium.
Beside
these popular fruits and vegetables, there are others that are not popularly
known or consumed. They are lesser known or underutilized because they are not
commonly seen and bought in the market and are not commonly found in the
environment. Such fruits and vegetables are found mostly in the forest. The
vegetables include Adensonia digitalta (Baobab), Commelina nudiflora (obogwu),
Myrianthus arboresu (Ujuju), Corchoruscapsularis (Jute), Cassia
occidentalis (Stinking peg), Ceiba pentandra (Silk cotton tree),Ficus
elasticoides (Ogbuike), Fiscus vogeliana (Ogbu aru), Celosia
argentica (Shokoyokoto), Moringa oleifera (Okwe oyibo) and Ceiba
pentandra (Akpu). The fruits includeIcacina trichantha oliv (ibiala,
ututuogiri, urubia), cola gigantea (oji eyi),Afromomium daniellia (ose
ohia), Diallium guineense (Icheku/ nnuagu/okponkporo).
1.2.
FRUIT
Broadly,
the botanical term fruit refers
to the mature ovary of a plant, including its seeds, covering and any closely
connected tissue, without any consideration of whether these are edible. As
related to food, the botanical term fruit
refers to the edible part of a plant that consists of the seeds and
surrounding tissues. This includes fleshy fruits (such as blueberries,
cantaloupe, poach, pumpkin, tomato) and dry fruits, where the ripened ovary
wall becomes papery, leathery, or woody as with cereal grains, pulses (mature
beans and peas) and nuts. In the broadest sense, the botanical term vegetable refers to any plant, edible
or not, including trees, bushes, vines and vascular plants, and distinguishes
plant material from animal material and from inorganic matter. Some fruits and
vegetables are popular because they are widely consumed, accepted, commonly
found in the environment and are grown in the gardens and farms.
They
are plentiful during the rainy season especially the popular ones; at this time
they are cheap. Suttle (1972) advised consumers to buy seasonal foods as they
are cheapest in season and also contain maximum flavour, colour and nutrients.
These popular vegetables include:Telfairia occidentalis (fluted
pumpkin), Vernonia amygdalina (bitter leaf),Amaranthus caidatus (African
spinach), Gnetum africanum (Okazi), Taliniumtriangulase (water
leaf), Curcurbita pepo (pumpkin leaf), Ipomea batatas (Sweet
potato leave), Ocimum gratissimum (Scent leaf/tea bush), Lypopersicon
solanium (Tomato), Abelmuschus esculantum (Okra), Lectucal stiva (Lettuce),
Piper cuineense (Uziza), Amaranthus spp. (Amanth leaves), Hibiscus
sabdariffa (Red sorrel), Brassica oleracea(Cabbage), Daucus
carota(carrot) andAllium cepa (onion). The fruits are Annona
muricata (sour sop), Prurous armeniaca (apricots), Rubuss trigosu
(rasp berries),Rubus villosus (black berries), Prunus persica (peach),
Persea americana (avocado pear), Fragaria virginiana (strawberries),
Pyrrus malus(apples),Carica papaya (pawpaw), Lichi sinensis (Lyche),
Mangifera indica (mango), Citrus limon (lemon), Psidum guajava
Linn (guava), Citrus sinensis (oranges), Ananas cosmosus (Pineapple),
Icocos nucifera (Coconut).The vegetables include Adensonia digitalta(Baobab),
Commelina nudiflora (obogwu), Myrianthus arboresu (Ujuju), Corchorus
capsularis (Jute), Cassia occidentalis (Stinking peg), Ceiba
pentandra (Silk cotton tree),Ficus elasticoides (Ogbuike), Fiscus
vogeliana (Ogbu aru), Celosia argentica(Shokoyokoto),Moringa
oleifera (Okwe oyibo) andCeiba pentandra (Akpu). The fruits include
the Icacina trichantha oliv (ibiala, ututuogiri, urubia), cola
gigantea (oji eyi) Afromomium daniellia (ose ohia) andDiallium
guineense (Icheku/ nnuagu/okponkporo).These edible lesser known fruits and
vegetables may contain some vital nutrients.
Fruits
and vegetables contain micronutrients and are rich sources of antioxidants that
sthe family needs. These fruits and vegetables have been found to contain some
indispensable micronutrients needed for good health. The antioxidant is among
the indispensable micronutrients. According to World Health Organisation (WHO)
(2000), antioxidants are‘magic wands’ that enable the body to produce enzymes,
hormones and other substance esessential for proper growth and development of
the body.The dependence on these popular fruits andvegetables alone for good
health is risky since they are not available all the year round and their
absence can affect the health and well being of the family. Popular fruits and
vegetables are known to reduce the actions of free radicals in the body because
they contain antioxidant. Duyff (2006) defined antioxidant as handful of
vitamins, minerals, carotenoids and polyphenols present in a variety of foods
that significantly slow or prevent the oxidative (damage from oxygen) process
or stress and so prevent or repair damage to body cells. These antioxidants are
found in plants, especially in fruits and vegetables.
1.3: CLASSIFICATION OF FRUITS
Olusanya et al. (1992) classified fruits into two broad groups: Fresh fruits
and dried fruits. The fresh fruits
include:
i.
Soft fruits e.g the
different types of berries, bananas, guavas, pineapples
ii.
Hard fruits e.g apples,
pears, plums, melons, mangoes,
iii.
Citrus e.g. oranges,
lemons, grapefruits.
The dried fruits include: figs, apricots,
dates, prunes and peach.
Fruits can also be classified according to
colour as Duyff (2006) noted them thus:
a)
Green fruits: These
include avocado, green apples, green grapes, honey dew, kiwi fruit, lime, green
pears.
b)
Orange and Deep yellow
fruits: These include apricot,
cantaloupe, grapefruit, mango, papaya, peach, pineapple, yellow apple and
yellow fig.
c)
Purple and blue fruits:
These include black berries,
blueberries, plums, purple figs raisins.
d)
Red fruits: These include cherries, cranberries,
pomegranate, red/pink grapefruits, red grapes, strawberries, water melon.
e)
White, tan, brown fruits:
These include banana, brown
pear, dates, white peaches.
1.4:
NUTRITIONAL COMPOSITION OF FRUITS
Fruits
are found to be rich in vitamins, especially vitamin C, minerals, sugar etc
(Achinewu, 1983; Oguntona, 1991). However, higher values for carbohydrate have
been reported in various fruits (Ossi and Ndukwe, 2008). The main sugars in
fruits are glucose, fructose and sucrose. Some fruits are low in carbohydrate
and consequently low in calorie.
1.4.1: Vitamins
The
main contribution of fruits and their products to nutrition is their supply of
vitamins most especially, the anti ascorbic vitamins (Ossi and Ndukwe, 2008).
Fruits and vegetables are the main sources from which primates derive their
vitamins. Ascorbic acid alongside other vitamins perform useful functions in
the body. Drugs such as asprin and the contraceptive pills affect the plasma
levels of ascorbic acid (Achinewu, 1983). Fruits contain a lot of ascorbic acid
(vitamin C) but most fruits contain small quantities of carotene and the B
group of vitamins.
1.4.2: Carbohydrate
Fruits contain carbohydrate in the form of
sugar, cellulose and starch. The cellulose is however indigestible and so add
bulk to the stool.
1.4.3: 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 growth and maturation of the fruit (Umoh, 1998). Fruits are
low in nitrogenous components as compared to seeds, leaves and some other plant
parts and tissues.
1.4.4: Fat
Fruits
are not good sources of fat and are usually recommended as part of weight
reduction diet. However, other fruits and seeds such as avocado and olive have
been reported to contain fats and oils (Sheila, 1978).
1.4.5:
Fiber
Fruits
and vegetables are sources of dietary fibre. Fibre normalizes blood glucose
levels and slows down the rate at which food leaves the stomach 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, fibre promotes a sense of satiety, or fullness, after
a meal, which prevents overeating and weight gain (James, 1995).
1.4.6: Moisture
The
water content of fruits is high, it ranges from 85%-90%.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).
1.5.0:
PHYTOCHEMICAL/ANTI-NUTRIENT
Fruits contain some anti-nutrients like
oxalates, tannin, phytate etc. These are important because of their significant
adverse effect on nutritional value of these fruits (Oguntona, 1998). High
levels of either phytate or oxalate inhibit the absorption and utilization of
minerals in animal and man (Sundarmaji and Markakis, 1997).
1.5.1: Phytate
Phytate is an important storage form of
phosphorus in plants. It is insoluble and cannot be absorbed in the intestine
(Siddhuraju et al., 1998). Phytate
has 12 replaceable hydrogen atoms with 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 et al.
(1991) reported that calcium absorption increases with low phytate (3.01 mg/g).
1.5.2:
Oxalates
These
are naturally occurring substances found in plants, and in humans. In chemical
terms, oxalates belong to a group of molecules called organic acids and are
routinely made by plants and humans. Our bodies always contain oxalates, 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 our
body from certain foods that contain them (Achinewu, 1983). Parivar et al. (1996) observed that low oxalate
content in 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.
1.5.3:
Tannins
Tannins
are astringent, bitter plant polyphenols that either bind or precipitate
proteins and various other organic compounds. The astringency from the tannins
is what causes 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 (Schneema et al., 2008)
If
ingested in excessive quantities, tannins inhibit the absorption of minerals
such as iron which may, if prolonged, lead to anaemia (Abayomi, 1986).This is
because tannins are metal ion chelators, and tannins chelated metal ions are
not bioavailable. Tannins have been shown to precipitate protein (Achinewu,
1983; Oguntona, 1991). Tannins do not affect absorption of either trace
minerals such as zinc, copper, and manganese in rats.Large quantity of tannins
may cause bowel irritation, kidney irritation, liver damage, irritation of the
stomach and gastrointestinal pain.
1.5.4:
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 (Parivar et at., 1996).
Saponins have been shown to posses beneficial (cholesteole lowering, and
deleterious (cytotoxic, permeabilization of the intestine) properties and to
exhibit structure dependent biological activities (Parivar et at., 1996). There are suggestions that the consumption of
saponins should be encouraged because of their nutritional importance. Harbone
and Williams (2000), reported 146mg of saponin to be safe level; this implies
that saponin levels above 146mg are toxic.
1.6:
ANTIOXIDANT AND ANTIMICROBIAL
The antioxidants are
substances that inhibit oxidation and can protect the body from the damaging
effects of free radicals. Antioxidants are the compounds found in plants
especially in fruits and vegetables. As described by (Harbone and Williams, 2000),
antioxidants are plentiful in plant foods particularly those that have bright
colours. There may be one or more antioxidant properties in a particular food.
Equally, Duyff (2006) postulated that the deeper and richer the colour of
fruits and vegetables, the more phytonutrients that are present. Duyff (2006)
noted that phytonutrients are bioactive compounds in food that promote health
by helping to slow the aging process and reduce risk of many diseases.
Phytonutrients work as an antioxidant, enhance immunity and communication among
body cells, causes cancer cells to die, detoxify carcinogen and repair damage to
deoxyribonucleic acid (DNA). As described by Whitney and Rolfes (2005), the
body needs to produce several antioxidative enzymes that will help to defend it
against free radicals. The concentrations of these enzymes are controlled both
by inherited genes and by influences affecting these genes which include the
diet. When body’s defense is weakened and production of antioxidants is
reduced, it is helpful to supplement antioxidants in the form of
antioxidant-foods. Conscious efforts should be made on the quality of diets
chosen in the family to supplement these antioxidants. The diet should contain
antioxidant minerals, vitamins and phytonutrient. Vitamins such as vitamin
A,C,E and minerals such as zinc,selenium,copper,manganese,iron and some of the
nutrient substances such as carotenoids, flavonoids, phenolics, polyphenols etc
are important nutrients with antioxidant activity. There are a variety of non acids
that are potent antioxidants. The body uses other dietary antioxidant vitamins
like theVitamin E, B, C and B12to keep the body healthy. Results of
antioxidant and antimicrobial studies, as well as molluscidal activities of the
plant substantiate its popular and wide traditional applications in treatment
of diverse ailments especially in the management of those caused by Vibrio spp
(Whitney and Rolfes, 2005).
The
antioxidants are found much in plants particularly those that have bright
colours such as citrus fruits, tomatoes, soybeans, whole grain foods as well as
nuts containing vitamin E. These food sources help in keeping the body healthy
and prevent the degenerative diseases in families.
1.7:
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:
1.7.1: Hydrating
effect
Fruits
and fruit juice, vegetables and vegetable juice are the most pleasant way of
hydrating the organism (Getahum, 1974). The water absorbed by sick person in
this manner has added advantage of supplying sugar and minerals at the same
time.
1.7.2:
Diuretic effect
Clinical
observations have showed that potassium, magnesium and sodium in fruits and
vegetables act as diuretic. The diuretic frequency of the urination is
considerably increased when fruits and vegetable juice are taken (MacGee,
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 is especially important in cases of edema
or swellings, kidney and heart conditions (Getahum, 1974).
1.7.3:Alkalinizing
effect
The
organic acids of the salts in fruits and vegetables provide alkaline carbonates
when transformed within the organism, which alkalizes the fluids. All the fruits
and leafy vegetables promote intestinal elimination. This keeps 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
valuable for quick energy and heat. Fibres in form of cellulose help
elimination of cholesterol. Fibre complexes with bile acids, which are
compounds manufactured by the liver from cholesterol, 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.
1.7.4:
Mineralizing effect
Fruit
furnishes minerals to the body. Some are rich in calcium and iron. These
minerals are essential for strong bone and teeth, respectively (Adamu et al., 2015). Two important minerals,
calcium and iron, found in vegetables are especially useful; calcium is for
strong bone and teeth, while iron is needed for blood formation and an
essential constituent of hemoglobin (Okigbo, 1977).
1.7.5:
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 (Pariva et at., 1996).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.
1.7.6:
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. Farrell (1999) 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.
1.7.7:
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 for 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.
1.8:
IMPORTANT HEALTH BENEFITS OF FRUIT
As
described by Duyff (2006), the important health benefits of fruits include:
i.
reduced risk of heart disease, type2 diabetes, and some cancers.
ii.
helps to maintain healthy blood pressure and perhaps reduce the risk of
developing
kidney
stones or possibly help reduce bone loss with age due to the potassium content.
iii. reduces
blood cholesterol levels, constipation and diversification in overall healthful
eating pattern.
iv.
promotion of growth and repair of all body tissues, helps to heal cuts and
wounds
and keeps teeth and gums healthy.
v.
fibre aids the digestive process.
vi.
folate helps form red blood cells
vii.
help many women reduce the risk of birth defects.
viii.
It may help to lower calories in meals and snacks since they are low in
calories.
1.9:
WILD FRUIT TREES
The use of wild plants in the native
diet, traditional medicine and religious ceremonies are widespread. Wild food
plant are those plants with edible parts, namely leaves, fruit, seeds, roots,
tubers, gums and sap, bark as well as pollen and nectar of honey (by bees),
that are growing naturally without having been purposely cultivated. All these
types of food provide essential elements in the human diet. For example, in
Nigeria, the fruit and leaves are still collected from the wild and consumed
directly by the house holds or taken to market. Wild food plants are relevant
to the house hold for food security and nutrition. In some rural areas,
particularly in the dry lands, they serve to supplement the staple food to fill
seasonal food shortages and as emergency food during famine (FAO, 1988). They
are used to generate income through the sale of fruits and fruit products,
medicine, gums and resins (Achinewu, 1983; Oguntona, 1991). The fruits are used
to compliment or supplement diets because they contain vital nutrients and
essential vitamins (Adepoju and Onasanya, 2008). For example, Diallium guineense fruit pulp and leaves
are rich in protein, carbohydrate, fibers, vitamins and other minerals (David et al., 2011).
The
pulp of Diallium guineense (black
velvet) has sweet taste due to high content of carbohydrate (reducing
sugar). It is a good source of vitamin B and C as well as phosphorous,
potassium and calcium. The pulp and leaves consist of protein and fat (AOAC,
2008). Diallium guineeense is used to
prepare Juice, Jam and Jellies. Furthermore, it is also used as a raw material
for the manufacture of several industrial products such as non- alcoholic
beverages (Aboyomi, 1986).
Despite
the huge benefits, most of the wild plants are at present, underutilized.
However, they play an important role in satisfying human nutrient demands,
because they are delicately flavored, attractive and have high therapeutic
values. They are in general, accepted as being rich in vitamins, minerals and
dietary fibre. Therefore, they are an essential ingredient of a healthy diet.
According to Okegbile and Taiwo (1990), the contribution of wild plants to
combating deficiencies in vitamins and micronutrients is essential in the
agriculturally marginal areas. Wild food plants are particularly most important
during periods of food scarcity (Joslyn, 1970).
Tuorila (2001) gave product characteristic which lesser known fruits met
to be:
a) Functional
foods that have a beneficial health effect
b) Genetically
modified products
c) Nutritionally
modified foods (having higher fibre content or reduced fat/sugar),
d) Organic
foods and
e) Ethnic
foods (having higher unfamiliar cultures).
1.10:
OVERVIEW OF DIALLIUM GUINEENSE
Diallium
guineense is a multipurpose tropical fruit used
primarily for its fruits, which are eaten raw or processed. The fruits and
seeds are processed for use as beverages. Diallium
guineense belongs to the dicotyledonous family leguminosae which is the third largest family of flowering plants
(Lewis and Nalakantan, 2005). It is widely grown as a subsistence crop for
meeting local demands. It is also grown commercially.Numerous national programs
have recognized Diallium guineense as
an underutilized crop with wide potentials since the demand for products is
substantial and the species can be incorporated into agro forestry systems.
There are also well established international trade channels. Further
exploration of
Diallium
guineense can therefore, provide added incomes for
poor rural people thereby improving their well-being.
Plate1:
Picture
of Diallium guineense fruit and Plate 2: Picture of Diallium guineense
Pulp leavesf)
1.10.1:Properties
of the Specie
Diallium
guineense is a nutritious fruit with a variety of
uses; the properties of this specie have been extensively studied, particularly
with reference to the component of the fruit. Diallium guineense has many valuable properties and virtually every
part of the tree has been utilized by both rural and urban dwellers (Adepoju,
2009).
1.11:
USES AND PRODUCTS
Diallium
guineense is a versatile plant which can be used
for many purposes. The unique sweet sour taste of the pulp is popular in making
non-alcoholic beverages (Handed, 1997). Virtually every part of the tree (wood,
root, leaves, barks, fruit and seeds) has some values to the rural people and a
number of commercial application are well known, others have the potential for
further development.
More commonly, the acidic pulp is
used as a favourite ingredient in production of non-alcoholic beverages used in
producing veltvet jam and jellies.Diallium
guineense drink popularly called velvet tamarind drink is popular in many
countries though there are many different recipes. In some African countries
the pulp juice is mixed with wood ash to neutralize the sour taste of the
tartaric acid, but the common method is to add sugar to make a pleasantly acid
drink. In Ghana, the pulp is mixed with sugar and honey to make sweet drink
(FAO, 1988). The fruits find much use as a flavuor for jelly. Most of the
producing countries manufacture drinks commercially. Sometimes it is fermented
into alcoholic beverages (FAO, 1988). In Nigeria, the fruit of Diallium guineense is utilized by the
population of such area either eating raw or soak in water for some minutes to
make juice for direct consumption.
1.12:
INDUSTRIAL USES
Diallium
guineensepulp is used as a raw material for the
manufacture of several industrial products such as Diallium guineense juice concentrate and non-alcoholic beverages
(Paroda, 2000).The powder produced from the seed is used in place of coffee by
the people of India (Handed, 1997).
1.13. STATEMENT OF THE
PROBLEM
For many years, the importance of
wide edible plants in the subsistence agriculture of developing countries, as a
food supplement or means of survival during drought and famine, has been over
looked. Although many wild food plants are used by the majority of the rural
population, they are still not appreciated or valued as some cultivated food
plants, such as mango, orange, pepper fruit and banana (Adepoju, 2009). In
Nigeria, where more than 80% of the population is rural, people have depended
on their traditional knowledge for the utilization of plants in their
surroundings. Despite the wilder role of wild edible plants in rural
communities, their utilization is still poor.
Like many
developing countries, Nigeria has nutritional problems of which the food of majority lacks essential nutrients.Consequently,
many people especially children suffer from malnutrition. Fortunately,
Nigeria is endowed with many varieties of such wild range of agro-climatic
conditions and soil type that make it suitable for the production of wild fruits
like Diallium guineense. Currently, a
higher percentage of Diallium guineense
produced in Nigeria is geared toward domestic market.Moreover, all studies
carried out discouraged the usage of vitamin, mineral and antioxidant
supplements but supports the fruits and vegetables as dietry sources. Adapting
to the traditional or lesser known fruits and vegetables would however, not
only improve the family nutrition but also prevent some of the chronic diseases
and other degenerative diseases. According to Srinivasa (2000), the solution to
the problem of
inadequacy of plant foods in the diet can be solved by exploitation of
neglected lesser known plants. Mnzava (1995) indicated that acceptance and utilization
of this specie is often constrained by lack of knowledge about their nutritive
values. There is therefore the need for the exhaustive study of the chemical
composition of underutilized plants such as Diallium
guineense.
However, wider research
had been done on the nutrient composition of the common domesticated fruits
such as mango, orange, pepper fruit and banana (Adepoju, 2009). Researchers and
consumers have concentrated on the fruit pulp of Diallium guineense neglecting the leaves as a possible source of
nutrients. There is therefore, limited information in the literature about the
chemical composition of Diallium
guineense leaves. Where few information (Achinewu, 1983; Oguntona, 1991)
are available, it is especially on the fruit pulp, it appears none had compared
the chemical composition of the fruit pulp and the leaves. Also, there has not
been available report on the Gas chromatography-mass spectroscopy (GC-MS)
analysis of Diallium guineense with
the aim of determining the major compounds in the sample. Lack of these
information contributes to underutilization of the plant.
1.14: Preservation/Storage of Diallium Guineense Products
The
fruit powder and leaves powder are the most common dried product of Diallium guineense. Drying is one of the
oldest preservation processes available to mankind, one that we can track since
prehistoric times. In today’s food market, dried foods play an important role
in the food supply chain. Dried products are stable and nutritious (Handed,
1997). As for fruits and vegetables, it can be estimated that they constitute
about 1% of the total dry matter in the food industry. The main feature of this
process consists on lowering the water content in order to avoid or slow down
food spoilage by micro-organism. Although the primary objective of drying is
preservation, quality aspects are more and more taken into account, in fact
according to the process carried out, one may end up with very different
products. As it is well known, food nutrient degradation, like any other
chemical/biological chemical reaction depends on temperature. According to the
food composition, the material is more or less prone to nutrients degradation,
the use of different drying technologies and process conditions for nutrient
and in general quality preservation is a necessity (Suttle, 1972).
1.15:
AIM AND OBJECTIVES OF THE STUDY
The aim of the work is to determine the
chemical compositions of the fruit pulp and leaves of Diallium guineense plant.
The aim is hoped to be achieved through
the following specific objectives:
i.
Determination of the
proximate compositions
ii.
Determination of the Mineral
contents
iii.
Determination of the
Vitamin contents
iv.
Determination of the
Phytochemicals contents
v.
The GC-MS analysis of the
methanol extract of the fruit pulp
Therefore, the
result of this study is expected to arouse the interest of consumers and food
processors to fully exploit the benefits of the plant.
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