ABSTRACT
Attempt was made to determine the nutritional and anti nutritional composition of Wild
melon (C. ecirrhosus ) popularly known as “Gunar shanu in Hausa land, using suitable
methods of analyses. The results for proximate analyses (% DW) showed a composition
of 3.73 ± moisture, 2.12 ± 0.08 ash content, 26.36 ± 0.10 crude protein, 50.67 ± crude
lipid, 2.17 ± 0.29 crude fibre, 18.69 ± 0.82 carbohydrate and energy value of 601.7 ± 8.75
Kcal/ 100g. Amino acids determination revealed a profile containing essential amino
acids for adults, but leucine, lysine, and threonine are below the requirement value for
14
children. The oil was found to composed of a combination of high concentration (67.3%)
of unsaturated fatty acids (linoleic acid C:18.2) and oleic C:18.1), and low concentration
(36.6%) of saturated fatty acids (stearic acid C: 18.0 and palmitic acid C:16.0). This
arrangement gave the oil good properties suitable for industrial and domestic activities.
High concentration of nitrate (151666±7637), phytate (136.04±1.54) and saponin (18.65
± 0.2mg/100gDW) were recorded in the seed, this is notwithstanding because boiling
reduce their effect to a minimum. The
overall result implies that seed of the wild melon possessed the potential to be used as a
source of nutrition.
TABLE OF CONTENTS
Title page………………………………………………………..
Certification………………………………………………………..
Acknowledgments
Dedication………………………………………………………..
Table of Contents………………………………………………………..
List of Tables………………………………………………………..
List of Figures………………………………………………………..
List of Plates………………………………………………………..
Abbreviation………………………………………………………..
Abstract ………………………………………………………..
CHAPTER ONE
1.0 INTRODUCTION AND LITERATURE REVIEW
1.1 Introduction………………………………………………………..
1.2 Justification………………………………………………………..
1.3 Literature Review………………………………………………..
7
1.3.1 Botany of the Plant………………………………………………..
1.4 Proximate Analysis…………………………………………………
1.4 .1 Moisture…………………………………………………………….
1.4.2 Ash………………………………………………………………….
1.4.3 Crude lipid………………………………………………………….
1.4.4 Carbohydrate…………………………………………………………
1.5 Amino acids…………………………………………………………..
1.6 Minerals……………………………………………………………….
1.6.1 Sodium ………………………………………………………………
1.6.2 Magnesium……………………………………………………………….
1.6.3 Zinc………………………………………………………………………
1.6.4 Copper……………………………………………………………………
1.6.5 Iron……………………………………………………………………….
1.6.6 Sulphur…………………………………………………………………..
1.6.7 Iodine…………………………………………………………………….
1.6.8 Calcium…………………………………………………………………..
1.6.9 Phosphorus………………………………………………………………
1.6.9(b) Chromium……………………………………………………………..
1.7 Antinutritional Factors……………………………………………………
1.7.1 Phytate……………………………………………………………………
1.7.2 Nitrate…………………………………………………………………….
1.7.3 Oxalic acid…………………………………………………………………
1.7.4 Hydrocyanic acid……………………………………………………………
8
1.7.5 Saponin……………………………………………………………………..
1.7.6 Tannin………………………………………………………………………
1.8 Aim and Objectives
Chapter Two
Materials and Methods
2.1 Materials…………………………………………………….
2.1.1 Sample Collection…………………………………………..
2.1.2 Sample Treatment ……………………………………….
2.1.3 Apparatus/Glass wares used …………………………………………..
2.1.4 Reagent Used……………………………………………….
2.1.5 Preparation of reagent………………………………………………
2.2 Methods…………………………………………………………
2.2.1 Proximate Analysis…………………………………………
2.2.1.1 Determination of Moisture Content…………………………
2.2.1.2 Determination of Ash Content………………………………
2.2.1.3 Determination of Crude Protein…………………………….
2.2.1.3.1 Procedure for the determination of Crude protein…………………
2.2.1.4 Determination of Crude Lipid……………………………….
2.2.1.5 Determination of Crude Fibre…………………………………..
2.2.1.6 Estimation of Available Carbohydrate …………….……………..
2.2.1.7 Determination of Energy Value…………………………………..
2.2.2 Minerals Analysis……………………………………………
2.2.2.1 Sample Digestion……………………………………………
9
2.2.2.2 Analysis of the Metals Using AAS………………………….
2.2.2.3 Analysis of Sodium and Potassium Using AES……………..
2.2.2.4 Analysis of Phosphorus………………………………………
2.2.3 Analysis of Amino acids……………………………………..
2.2.4 Analysis of Fatty acids……………………………………….
2.2.5 Analysis of Anti nutritional Factors………………………….
2.2.5.1 Determination of Phytate……………………………………..
2.2.5.1.1 Procedure for the determination of Phytate……………………
2.2.5.2 Determination of Total Oxalate………………………………..
2.2.5.2.1Procedure for the Determination of Oxalate ………………………
2.2.5.3 Determination of Tannins………………………………………….
2.2.5.3.1 Procedure for the Determination of Tannins………………………
2.2.5.4 Determination of Hydrocyanic acids…………………………
2.2.5.4.1 Procedure for the determination of Hydrocyanic acid………………………
2.2.5.5 Determination of Nitrate……………………………………………………..
2.2.6 Nutrient Density……………………………………………..
2.2.7 Characterisation of the Seed’s Oil……………………………….
2.2.1.4 Determination of Saponification Value…………………….
2.2.1.5 Determination of the Acid Value…………………………..
2.2.1.6 Determination of the Peroxide Value……………………….
10
2.2.1.7 Determination of the Iodine Value…………………………
2.2.2.0 Statistical Analysis………………………………………….
CHAPTER THREE
3 RESULTS AND DISCUSSION
3.1.0 Results……………………………………………………………..
3.2.0 Discussion…………………………………………………………
3.2.1 Proximate Analysis……………………………………………….
3.2.2 Minerals Analysis…………………………………………………
3.2.3 Nutrient Density…………………………………………………..
3.2.4 Anti Nutritional Analysis and Predicted Minerals Bioavailability…..
3.2.5 Amino acids………………………………………………………….
3.2.6 Fatty acids……………………………………………………………
3.2.7 Chemical Analysis of the Oil…………………………………………
CHAPTER FOUR
4.0 CONCLUSION AND RECOMMENDATION
4.1 Conclusion……………………………………………………
4.2 Recommendation……………………………………………..
11
CHAPTER ONE
1.0 INTRODUCTION AND LITERATURE REVIEW
1.1 Introduction
Food is no doubt the most basic necessity for one to effectively function in his own
ecosystem. It is a substance that often composed of carbohydrate, fats, protein and water
which are eaten or drunk by animals or humans for nutrition (Aguilera and David, 1999).
The constituent in food contains important chemical substances known as nutrients.
These are ingested, digested, absorbed, and circulated in the blood streams to feed the
cells which constitute the body building blocks and consequently, the increase in body
resistance to diseases and faster recovery of illnesses is witnessed (Shiels et al., 2005;
Worthington – Roberts, 2008).
15
Most of the food consume by humans are sourced from plants and animals, the former
has been grouped into; leafy vegetables, seeds, tubers and fruits (Oyiza, 2005). There are
over 30,000 known edible plants, from which only 300 were domesticated and more than
95% of the required human plant food were obtained (Tabuti et al., 2004).
This is not surprising because the utilization of plant as part of the human diet can be
traced back to the emergence of the first man on earth; Adam and Eve and forbidden
Fruits or Apple (Onibun et al., 2007). The part of the plant responsible for bearing of
seeds is known as Fruit, and is considered a healthy food supplement because it
composed of an appreciable amount water, carbohydrate, proteins, lipids, vitamins and
minerals; Ca, Mg, K, Zn and Fe (Wenkam, 1990 and Umar, 2010). Also, the Leafy
vegetables are rich in proteins and were rated high in amino acids profile (Itanna, 2002;
Kala and Prakash, 2004; Gupta et al., 2005; Ogbadoyi et al., 2006; Kala and Prakash,
2006). Moreover, in the stem bark and the roots presents Phyto chemicals with
chemotherapeutic benefits (Umar, 2005). However, despite the nutritional benefits
ascribed to different parts of the plant, anti nutritional factors which blocked the
bioavailability of some mineral elements and change the nutritional status of the food are
also present (Ewaida, 1993; Lo – voi et al., 1995).
Meanwhile, the realization of the significance of plants in furnishing the basic nutrients
necessary for healthy growth of an individual has prompted the world researchers into the
investigation of the nutritional status of various plants with the aim of introducing more
plant food required to control the alarming food shortage in the Human nutrition (Al –
Sahib and
16
Marshall, 2003; Anwange et al., 2004; Hassan et al., 2004; Amarteifio and Moses,
2006;Nkafamia et al., 2006; Dahiru et al., 2006; Umaru et al., 2007;Bello et al 2008;
Hassan et al., 2008;Rathore, 2009).
1.2 Justification
Literature has shown that plant materials have for long served an important role in human
welfare by providing various essential needs ranging from food substances to medicinal
agents (Bhat and Sridhar, 2008).The plant under investigation grow in the wild within the
study area, and has not been fully utilized as source of food due to ignorance about its
nutritional information. Therefore, it has become imperative to investigate its nutritional
contents and made the information available for the people to utilize and solve some of
their nutritional and medicinal problems.
1.3. Literature review
1.3.0 Botany of the plant
Wild melon (Citrullus ecirrhosus (Celestin A Cogniaux 1888) is a plant of the
Cucurbitacea family that plays a vital horticultural role in Africa. The plant is a native of
Namibia, south Africa particularly Nambi desert. It is widely distributed in the tropical
regions of Africa, and the globe in general. The plant is called Gunar Shanu (cow melon)
in the north – western part of Nigeria. It is cultivated in the northern areas of Borno,
Yobe, kano, and Jigawa states, relatively for its high oil content as a cash crop (Maina
and aliyu 2009). It is cultivated for its seed in the arid and semi arid areas of northern and
eastern part of India, either as a monoculture or as a mixed culture with pearl millet or
17
sorghum, both in the summer and rainy seasons (Joshi, 1990). The plant can survive in a
desert with little water and lots of sunlight. It was reported that the plant can withstand a
harsh climates and environmental conditions than any other, hence it can grow in a wide
range of places from deserts to swampy (fadama) and in a rocky places (Hui, 1992). This
has clearly shown that the plant has no defined minimum or maximum rainfall
requirements. Also, it was found that a cup of water is enough for the plant to grow
(Maina and Aliyu, 2009). According to Jeffery, 1978; Wild melon plant has a long stems
(up to 10 m) lying or creeping on the ground, with curly tendrils. Its Leaves are 5-20 by
3-19 cm, and a hairy, usually deeply palmate with 3-5 lobes, on 2-19 cm long petioles.
Male flowers have 12-45 mm long pedicels, and are 1-2.5 cm long, pale green. The
flowers are monoecious, solitary on pedicels and are about 45 mm long; with 5 shortly
united petals, and pale green.
The fruits of wild melon plants are 1.5-20 cm in diameter, subglobose, greenish, mottled
with darker green or yellowish and evenly coloured or striped. They vary considerably in
morphology, ranges from small and round to the large oblong fruits. In addition, the fruits
are indehiscent berry containing many flattened seeds embedded in a bitter taste flesh
(Brandwijk-Breyer and Watt, 1962). Each fruit contains 10-12% seeds by weight (Singh,
1983). The Seeds of smaller and striated pods are black with thick and hard pericarp and
relatively rough, while that of the unstriated pods are smooth and yellowish. The latter is
considered to have high yield of oil (Formo et al., 1979).
Nutritional as well as medicinal applications of different parts of the plants of
Cucurbitacea have variably been reported (Hurchings et al., 1996). The Oil seeds are
widely employed in domestic activities and have high nutritive values which made them
18
a good source of proteins with defatted cakes capable of being used as a protein
supplement in human nutrition (Achu et al., 2005; Chinyere et al., 2009). Wild melon
seed in particular is believed to have high oil content, also being a legume; it is expected
to have appreciable protein content. Moreover, the quality of its oil was found to be
similar to that of groundnut depending on the processing method (Maina and Aliyu,
2009). The flesh is served to animals as feed and the seed kernel is highly utilized as
condiment (Madhusweta, 2002).
Plate; 1.0: Wild melon (C. ecirrhosus) plant with Fruit (unripe).
19
Plate; 1.1; Wild melon (C. ecirrhosus) Fruits (ripe).
20
Plate; 1.2: Wild melons (C. ecirrhosus) seeds.
In a related development, research conducted in India madhwsweta et al., (2002), showed
that the seed kernel of Citrulus lanatus (Karingda) another Cucurbitacea specie contain
an appreciable proteins, fats, fibre, Ash, and carbohydrate to the tune of 40.02, 49.5, 1.79,
2.71 and 5.53 percents respectively.
Similar analyses were conducted in sudan and North-Eastern Nigeria on the wild species
of water melon; Gurum (ziyada El-hussein, 2008) and Guna (Maina and Aliyu, 2009).
The results of the analysis showed a crude protein content of 27.2% (Guna), and 30-33%
(Gurum). However oil contents of 35% (Gurum) and 46.88% (Guna) respectively. But,
low levels of trace elements have been reported from both analyses.
The information obtained from above analysis have clearly signals that wild floral
particularly cucurbitacea could be utilized as a solution to the world demands for oils
21
and fats in order to meet the multiplex human consumption and the multitudinous
industrial needs, for boosting the national economy (charley, 1982).
However, the fatty acid composition of Cucurbitacea, was reported to be species
dependant with pumpkin and water melon seeds reported as successful sources of good
quality edible oil and proteins for human consumption (Chowdhury et al., 1985; Sawaya
et al, 1983; Kaue et al., 1958; Lazoso, 1986; Akoh and Nwosu 1992).
Proximate Analysis
This is the separation and determination of different classes of the nutritional
components of a mixture; moisture, alcohol extract, petroleum ether extract, water
extract, hydrochloric acid extract, free acids, esters, resin, starches, crude protein, crude
lipid, reducing sugar etc (Sharma et al., 2002).
Moisture content
This is the amount of water content in a sample. It is often expressed as percentage. The
moisture content of a sample indicates its storage quality. However, the value greater
than 15% promotes the growth of bacteria and fungi with a detrimental effect on the
sample composition (Onimawo et al., 2003).
Ash content
This is the amount of the inorganic residue that remains after the removal of water and
organic matter using heating in the presence of oxidizing agent. Ash content of a sample
gives a measure of the total amount of minerals present in a sample. Low or high value of
ash content in a sample indicates its quantity of essential minerals (Umar et al., 2006).
22
Crude lipid
These are biologically active compounds that are insoluble or partially soluble in water
but soluble in non-polar organic solvents such as benzene, ether and chloroform
(McDonald et al., 1995). Lipids are broadly classified as simple lipids and complex
lipids. The former are those which do not contain fatty acids and include steroids and
terpenes. While the latter are those which are esters of long chain fatty acids and
comprise of glycerides, glycolipids, phospholipids, and waxes (Sharma et al., 2002).
According to Umar, (2005) Lipids in plants are of two types namely; the structural and
storage. Structural lipids are constituents of various membranes and protective surface
layers and composed about 7% of the leaves of higher plants. Storage lipids on the other
hand are present in seeds and fruits, and this kind of lipid are predominantly oil.
Oils and Fats are the triesters of glycerols with a long chain carboxylic acids (12 to 20
carbons).
Fats contain a saturated alkyl chains and is solid at room temperature, oils in contrast are
liquid and contain an un saturated chains.
The carboxylic acids in the triglycerides are known as Fatty acids, and occur naturally as
un-branched with an number of carbon atom (4- 24 C atoms per molecule) and are may
be saturated (Barde, 2010). Unsaturated fatty acids exist as either monoenoic containing
1, 2 double bonds per molecule or poly un saturated fatty acids with the cis and trans
arrangements of its double bonds, but the former configuration is the form in which most
fatty acids occur naturally (McDonald, et al., 1995). Some of the polyenoic fatty acids are
called essential fatty acids; Linoleic acid (18:2) T- 6, α- linolenic acid (20:3) w 3, and
arachidonic acid (20:4) w 6. These essential fatty acids are primarily sourced from
23
terrestrial plants (notably oil seeds) and marine plants and animals (e.g Phytoplankton
and fish) (McDonald et al., 1995; Al-Jedda and Robinson, 2002). They can not be
synthesized by the body, hence the name essential fatty acids and are very important and
necessary for the energy, growth, cellular metabolism and muscle activity. Moreover,
some essential fatty acids serve as a vital dietry precausor in the formation of eicosanoids
(Prostaglandins, thromboxane and prostacyclins) and provide useful information to the
study of their roles in health and diseases (Kolanowski et al., 1999; Barde, 2010). The
names of some fatty acids are shown below;
Table 1.0; names of some fatty acids
Common name (systematic name) Designation Structural Formula
Butyric acid (Butanoic acid) 4.0 CH3(CH2)
2COOH
Caproic acid (Hexanoic acid) 6.0 CH3(CH2)4COOH
Caprylic acid (octanoic acid) 8.0 CH3 (CH2)6COOH
Capric acid (Decanoic acid) 10.0 CH3(CH2)8COOH
Leuric acid (Dodecanoic acid) 12.0 CH3(CH2)10COOH
Myristic acid (Tetradecanoic acid) 14.0 CH3 (CH2)12COOH
Palmitic acid (Hexadecanoic acid) 16.0 CH3 (CH2)14COOH
Stearic acid (Octadecanoic acid) 18.0 CH3(CH2)16COOH
Arachidic acid (Eicosanoic acid) 20.0 CH3 (CH2)18COOH
Behenic acid (Docosanoic acid) 22.0 CH3(CH2)20COOH
Lignoceric acid (9- Tetracosanoic acid) 24.0 CH3(CH2)22COOH
Palmitoleicacid(9-Hexadecenoicacid) (16.1)9(T-9-16.1)
CH3(CH2)5CH=CHCH2)7COOH
24
Oleicacid(9-Octadecenoicacid) (18.1)9 (T-9-18.1)
CH3(CH2)7CH=CH(CH2)7COOH
Carbohydrate
These are class of naturally occurring organic compound which formed the main
components of all types of plants (about 3/4th of the dry weight of the plant kingdom)
(Sharma et al., 2002). A compound of carbohydrate constitute of the atoms, hydrogen,
and oxygen with the ratio of the latter atoms being 2:1. Each compound conform to the
general formula CxH2yOx where x and y are whole numbers (Kutama, 2008).
Carbohydrates are generally regarded as poly functional because they constitute of
alcohols, aldehydes or ketones in their structure, hence the classification as Polyhydroxy
– Aldehyde (Aldoses) or Polyhydroxy – Ketone (Ketoses). They also yield these
functional groups on hydrolysis, and moreover, they are referred to as Saccharides, which
means sugars (Robert et al., 1986).
Sugars are grouped into Sugars and Non – Sugars. The former have characteristic sweet
taste, crystalline nature and are water soluble. Moreover, they are categorized as
monosaccharide; containing single unit of carbohydrate which cannot be hydrolyzed to
yield smaller molecules e.g glucose and fructose(C6H12O6), and Oligosaccharides;
25
containing two or three molecules of monosaccharide joint together, known as
Disaccharides (for 2 joint molecules) e.g Maltose, sucrose (C12H22O11), or Trisaccharide
C12H22O11 + H2O + H+ → C6H12O6 + C6H12O6
(Sucrose) (Glucose) (Fructose)
C18H32O16 + H2O + H+ → C6H12O6 + C6H12O6 + C6H12O6
(Raffinose) (Glucose) (Fructose) (Galactose) (Finar, 1973).
Plants make up Glucose (C6H12O6) in the presence of sunlight by the reaction of Carbon
(iv) oxide and water through a process known as photosynthesis as shown in the equation
below;
6CO2 + H2O —sunlight→ C6H12O6 + 6O2
The Glucose produced accounts for 50-75% of the total dietary energy reserved in the
form of starch or cellulose of the plant supportive tissue. Animals on the other hand,
obtained their carbohydrate from plants through the food chain. The carbohydrate in the
form of Glycogen is converted to energy and carbon (iv) oxide (kutama, 2008), as shown
below in equation. Both glucose and fructose are collectively obtained from naturally
occurring foodstuffs; Glucose is particularly and are used as; sweetening agent in syrups
and confectionary, food for infants and patients, raw materials for wine and alcohols.
Fructose are used as ; medicinal syrups, sweetening agent and a substitute to sucrose by
obese and diabetics, while sucrose is being utilized as; an ingredient in the manufacture
of a compound known as sucrose octaacetate needed to denature alcohol which renders
paper transparent and make anhydrous adhesive, food and ingredients for jams, jellies,
and confections syrups (Barde, 2010).
C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy
26
(Glucose)
The latter group of carbohydrate (non-sugar) is non crystalline, quite heterogeneous,
insoluble in water, not sweetly taste, and yield large number of monosaccharide molecule
on hydrolysis e.g starch and cellulose (Finar, 1973; Umar, 2005). They are polymeric
structures formed by repetitive units of either mono or di-saccharides joints by glycosidic
bonds to yield a molecule with a very large number of carbon (ranges between 200 and
250), e.g starch and cellulose (Varki et al., 2008). The starch molecule contain linear
structure with slight modifications of the repeating units called α-glycosidic bonds while
cellulose is β-glycosidic bonds which consist of two types of molecules namely; the
linear- helical amylose (contain 20 to 25% amylose) and the branched amylopectin (75 to
80% amylopectin) (Umar, 2005), as shown @@@@@
The cellulose is the basic structure of the plant cell wall and formed the numerous and
unique polymer in the plant kingdom (McDonald, 1995).
Amino acids
These are compounds containing both amine and carboxylic acid functional groups,
hence referred to bi functional compounds. The structures are arranged in such away that
27
hydrogen at α β and γ positions are replaced by amino group. The general formula is
shown below; @@@@@
Where R = alkyl, aryl or any other group
Presence of the two functional groups in the amino acid presents a unique a feature
known as Zwitterion which is the occurrence of a dipolar ion on dissolving the acid in
water with the release of a proton. The released proton from the carboxylic acid
functional group is attracted to the lone pair of electrons of the NH2 group, leaving the
acid group with a negative charge and the emergence of positive charge in the amine
group, as result the resultant ion become electrically neutral. @@@@@
Zwitterion changes to either positive or negative ion when dissolve with acidic or basic
solutions. But a point is archieved known as “isoelectric point” when the amino acid
shows no tendency to change as a result of placing the ion in an electric field, by varying;
the PH of the acidic or basic solution and the condition of the electric field
(eletrophoresis), and this is the method used to identify and separate the amino acids from
a mixture (Nelson and Cox, 2005; Abubakar, 2007).
Amino acids are the building block of proteins, hence a hydrolysis of proteins by strong
inorganic acid and enzymes yields a mixture of amino acids. Thus, about 25 amino acids
(some are arranged in table 2) were discovered from proteins, 10 of which are very
28
essential and lack of any one by the body is witnessed by its inability to grow, and these
can even lead to death (Finar, 1973).
Proteins are polymers of amino acids molecules (usually in the range between 200 to
600) join together by eliminating water molecule between their NH2 and COOH groups
which constitute the major part of human body such as nails, muscles, and skin that
undertake a crucial life process in the human body system, and posses a relative
molecular masses from 17,500 to 60,000 (Nelson and Cox, 2005). As shown ;
@@@@@
The hydrogen bonding and ionic interactions exist between the peptide linkages in
proteins (Murray et al., 2006). These binds the protein polymers together in to a helical
structure, pleated sheets and even tertiary or quaternary structures as in globular proteins
or haemoglobin and some enzymes. The binding forces in the protein molecules become
disrupted due to the increase in molecular vibrations generated by heating and thus, the
protein become coagulated (or precipitated) and its physiological activities lost (Hendrix,
2009).
Table 1.2; Name of some amino acids
Amino acid (Abbreviation) Structure
Glysine (Gly) H2C(NH2)COOH
Alanine (Ala) CH3CH(NH2)COOH
Valine (Val)* (CH3)2CHCH(NH2)COOH
29
Leucine (Leu)* (CH3)CHCH2CH(NH2)COOH
Isoleucine (IIe)* CH3CH2CH(NH2)CH(NH2)COOH
Serine (Ser) HOCH2(NH2)COOH
Threonine (Thr)* HOCH2CH(NH2)COOH
Cystein (Cys)* HSCH2CH(NH2)COOH
Methionine (Met)* CH3S(CH2)2CH(NH2)COOH
Aspartic acid (ASP) H2NCH(NH2)NH(CH2)3CH(NH2)COOH
Lysine (Lys)* H2N(CH2)4CH(NH2)COOH
Glutamic acid (Glu) HOOC(CH2)2CH(NH2)COOH
Glutamine (Glu- Q) H2NCO(CH2)2CH(NH2)COOH
Arginine (Arg) H2NC(NH)NH(CH2)3CH(NH2)COOH
*Essential amino acids
Source; McDonald et al., 1995
Minerals
These are chemical substances that emanated from geological activities from which life
on our planet is built upon. They enter into our body through the food we have taken.
They are present in larger percentage in our body tissues and are classified according to
their metabolic roles in the body that are necessary for health and growth, as essential and
non essential elements respectively (Umar, 2005). Essential minerals were further
30
classified into macro and micro or elements. The former comprise the calcium,
phosphorus, potassium, chloride, and sulphur and magnesium. Where as the latter include
iron, iodine, copper, manganese, Zinc, cobalt, molybdenum, selenium, chromium and
fluorine depending upon the concentration needed in the body. Also, being part of the
human body, their deficiency particularly those of elements is associated with the global
burden of diseases and disability such as mental impairment and death from infectious
diseases (Umar, 2005).
The uses, recommended daily intake and toxic effects of sodium elements as
summarized by Wilson, (2008) and Lentech, (2009) were; Sodium (Na), helps to regulate
blood pressure, fluid balance, transport of carbon dioxide, affects cell membrane
permeability and some of its other functions. Moreover, it was added that sodium
influences osmotic pressure and pH in the body and it is easily absorbed and excreted by
the kidney (Adeyeye, 2002). The deficiency of sodium can cause fatique and fluid
imbalances brought about by dehydration due to lowering of osmotic pressure
(McDonald et al., 1995). The recommended daily allowance of sodium set by National
Research Council, (1989) is 200- 500mg for adult.
Magnesium (Mg); is required by over 500 enzymes that regulate sugar metabolism,
energy production, cell membrane permeability, and muscle and nerve conduction. It was
added that magnesium serve as intercellular fluid (Heineman, 1980), and also functions in
stabilizing some structures and energizing others in all types of biopolymers e.g DNA
and RNA, proteins, polysaccharides and lipids (Garba, 1999). The deficiency in
magnesium causes an uncontrollable twisting of muscles which results into convulsion
and even death of the patient, severe diarrhea, migraine, hypertension, cardiomyopathy,
31
atheriosclerosis and stroke (Hegarty, 1988; Guthrie, 1989). The recommended daily
allowance of magnesium in take for children below 10 years are 150 mg, and 200-300 mg
for those above, while 300-400 mg and 300 mg was recommended for men and woman.
Zinc is the fourth very essential micronutrient after vitamin A, iron, and iodine (Umar,
2010). It is required by more than 50 enzymes in their synthesis. It also act as catalyst
regulator of acid and proteins in mitosis cell division and in the generation of growth
(Abubakar, 2007). It also helps in the development of genital organ and in the
maintenance sexual function because it is mainly found in large amount in the testis,
epididymis, prostate gland and semen. Moreover, zinc is very important in the
maintenance and development of human vision as it is obtained in the retina and choroid
where it functions. Zinc is also contained in the saliva where it acts as a mediator,
affecting taste and appetite. It also posses the following regulatory functions; controlling
the functions of metallo- enzymes, partake in the synthesis of DNA, RNA and protein,
and standardizing the interaction between ligand – receptors and receptor – target organs
(Ertan et al., 2002; Camara and Amaro, 2003; Barde, 2010; Wilson, 2008). Deficiency in
Zinc may lead to impotency due to weakness of sexual organs, and retard of sexual
maturity in children, it may also affect vision and the ability of the eye to adapt to
darkness. The daily recommended intake of Zinc is about 15-30mg (Abubakar, 2010).
Copper is an element associated with estrogen, which helps to normalize fertility in
woman and miscarriage. It is very essential in the body because as it is contain in a
protein that release iron from the cells to the plasma. In erythrocytes, it plays a role in the
digestion of oxygen molecules, and in cytochrome which is the enzyme responsible in the
32
energy breakdown (Ysart et al., 2000; umar, 2005). The deficiency in the copper
according to Adeyeye, (2002), is associated with diseases like anemia and menkes,
brought about by failure of copper absorption. The symptoms for the above ailment are
nausea, vomiting, and diarrhea and intestinal pain (Umar, 2005). The recommended
intake of copper daily is given as 0.5mg/kg of the body weight (Ysart et al., 1999).
Iron is found as the constituent of heamoglobin in the red blood cells (Abaye, 1998), and
in myoglobin which is a constituent of muscles, storage iron (ferritin and haemosiderin)
mainly obtain in the spleen, liver and bone marrow. Although an essential nutrients in
human nutrition, iron is an important factor in many biochemical process, especially its
vital function in building up an organic catalyst concern with a redox processes in the
living cells, such as the liberation of energy from carbohydrates, fats and proteins (Abaye
et al., 1998 ; Al- Haddad et al., 1999; Umar, 2010). The deficiency in iron manifested in
the poor learning ability due to a decrease in the cognitive development (FAO, 1997), it
also causes anaemia which is responsible for fifth of neonatal mortality and a tenth of
maternal mortality and for account for about 800,000 deaths worldwide(Black, 2003).
Sulphur is the constituent of proteins containing amino acids, and in the vitamins biotin
and thiamin, hormone insulin and coenzyme A (Barde, 2010). The element is absorbed
by plant from soil via the roots in the form of sulphate ions and reduced to sulphide
before it is incorporated into cysteine and other organic sulphur compound (Puacz et al.,
2001). Little attention was given to the deficiency of sulphur, this was due to its
association with proteins (Umar, 2005).
33
Iodine is secreted by the only gland known as thyroid gland via two already produced
hormones; triiodothymine and tetraiodothyronine (Thyroxine), from it is distributed all
over the tissues in the body. The hormones functions at in speeding the reactions
occurring in most of the body tissues and organs, thereby increasing basal metabolic
rates, accelerating growth and increasing the consumption of oxygen by the whole
organism, They also effect the development of the brain in a foetal (McDonald et al.,
1995; Moon and Kim, 1999). The deficiency in iodine may cause foetal wastage and
neural damage (before after birth) as well as cognitive activity – intelligence quotient
(IQ) in the school age children (Moon and Kim, 1999; Kaoil et al., 2002; Black, 2003).
Also, endemic goiter a disease which result from a decrease in the thyroxin production is
the manifestation of iodine deficiency in adults (McDonald, et al., 1995), which
according to a research, Over 25 million people are at risk of iodine deficiency disorders
(IDD) from which 4 million children are affected with approximately 1.5% to 3.5% of
them being mentally retarded (Delena and Adelekan, 2003). But interestingly, recent
report indicated that most of these IDDs were overcome due to consumption of iodized
salt by 95% of Nigerian house hold, with the urine samples of the majority having iodine
values above 100μgL-1, which shows improvement in iodine status (Delana and
Adelekan, 2003).
Calcium (Ca), is the most abundant element in the human body (about 2% of its weight)
(Kamchan et al., 2004). It is required for many physiological and biochemical activities
in the body and is also very essential for a sufficient mineralization of bone and teeth; is
considered as the primary determinants of bone strength (Glew and Vanderjagt, 2006). It
is found in trace amount in the body fluids as calcium ions or in combination with
34
proteins for activating the enzymes especially those required in the transmission of nerve
impulse, however, about 99% of the total body calcium is contained in the teeth and
skeleton (Aganga, et al., 2003). Studies have also indicated that absorption of calcium
could help in the control of blood pressure, appearance of colon cancer, pancreatitis and
the surrounding vascular tissue (Jodral- Segado et al., 2003; Umar, 2010). The deficiency
in calcium(with phosphorus and vitamin D) was reported to have cause; a disease known
as rickets in children, demineralization in skeleton that results to fragility of bone
(Osteoporosis), and adults rickets (osteomalacia) (Adeyeye, 2002).
The recommended daily allowance for calcium was suggested by the US National
Institute of Health to be 800mg and 1500mg for an average adult and pregnant women,
nursing mothers as well as the elderly respectively. Moreover, 1000mg was
recommended for children (Abubakar, 2007).
Phosphorus is the most abundant minerals (700g) in the body, after calcium (1200g), with
a 25% less than the recorded amount in women (Krause and Hunscher, 1972). The
element is always associated with calcium in the body in the provision of supportive
structure because it about 80-85% of its total amount is concentrated in the skeleton
found as hydroxyaptite, 3Ca3(PO4)2. Ca(OH)2 (Adeyeye, 2002; Umar, 2010). In the cells
and blood, Phosphorus is present as soluble sulphate ions, likewise in lipids, proteins,
carbohydrates, nucleic acids and nucleoproteins charged with the activities of cell
division, reproduction and the transmission heredity traits (Adeyeye, 2002). The
deficiency of calcium in the body cause poor fertility, apparent dysfunction of the ovaries
causing inhibition, depression or irregularity of oestrus (Umar, 2010)
35
Chromium has an average concentration 100ppm in the earth crust, and its compounds
emanated as a result of erosion of the chromium containing rocks that emerge from
volcanic eruptions (Kotas and Stasicka, 2000). It is present in the food and biological
systems as Cr3+ and is required in trace amount for the digestion of sugars and lipids in
humans (Gonzalez et al., 2005). Contrarily, the hexaflouro form of chromium (Cr6+) is
toxic and can readily found in foods (Ysart et al., 1999), its compounds are irritants,
corrosives and easily absorbed by the lungs, digestive tract and skin. The toxic effect in
humans includes; haemorhagic gastroenteritis, hepato-cellular deficiency with uterus
disseminated intravascular coagulation, coma and eventually death. Also its associated
skin cancer on reaction with thio-amino acids to form Cr3+ allergic complexes (Baruthio,
1992; mutuma et al., 1999). Human beings have the ability to oxidize Cr3+ to a potentially
carcinogenic Cr6+ compound, hence high intake of Cr3+ has not shown any deleterious
effects (Mutuma et al., 1999). The daily allowance of chromium was recommended to be
50-200ug (NRC, 1989). Also, the deficiency in chromium intake may cause a disease
known as chromium deficiency, which includes blurred vision, shaking, fatique and poor
insulin binding (Baruthio, 1992; Gonzalez et al., 2005).
Antinutritional factors
These are compounds with the ability to hinder the bioavailabity of important minerals
(nutritional compounds) coexisting together due their poisonous nature. Presence of these
compounds is often a greater set back in utilizing some plants particularly vegetables as
source of microelements for prevention against diseases (Umar, 2010). Some of the anti
antinutritional compounds includes; oxalate, phytate, tannin, nitrate, saponins and
hydrocyanic acid.
36
Phytate is the principal storage form of phosphorus in many plant tissues (fuller and
Garlich, 1994). This form of phosphorus is not beneficial to humans because of the
absence of enzyme (phytase) necessary to separate the phosphorus from phytate
molecule. The phytic acid and oxalic acid are strongly chelates essential minerals such as
Ca2+, Mg2+, Fe2+, and Zn2+ thereby contributing to their non-bioavailability, and
consequently led to health problem such as oxalemia (More and Wood, 1986; Aboaba
and Ketiku, 1993; Obadoyi, et al., 2006; Umar, 2010).
Human beings often obtained nitrate on consuming vegetables as well as from drinking
water (Umar, 2010). The nitrate (4-8%) with low level of acute toxicity is changed by the
microflora in the oral cavity to nitrite which has much higher acute toxicity (Petersen and
stoltze, 1999; Zhong et al., 2002).
The nitrite produced when present in the body may lead to the formation of carcinogenic
nitrosamines and methaemoglibinaemia which an infants disease (Ward et al., 2006).
Nitrite has the ability to react with the haemoglobin (oxyHb), by oxidizing the iron (ii) to
iron (iii) to form metHb, and consequently blocked the oxygen delivery to tissues (Umar,
2010).
NO2
– + oxyHb(Fe2+) → metHb(Fe3+) + NO3
–
Once the proportion of metHb reaches 10% of normal Hb levels, a clinical symptom
known as blue baby syndrome (methaemoglobinemia) occur. But children and adults are
far less susceptible to the blue baby syndrome (Benjamin, 2000).
Moreover, contrary to health problem cause by nitrate consumption. Nitrite was reported
to be use as an effective antimicrobial agent (Benjamin, 2000). It was also reported that
nitrite minimize tissue damage caused by heart attack (King, 2008). Also, the N- nitroso
37
compounds the potential cancer causative agents, was reported to be inhibited after a
meal of vegetables containing nitrate is followed with fruits containing ascorbic acid,
indicating that the cancer causing compounds are inhibited by ditary antioxidants
contained in vegetables and fruits (Ward et al., 2006; Umar, 2010).
Oxalic acid (ethanedioicacid) is the most important dicarboxylic acids found in rhubarb,
sorrel, tomatoes and plants; formed on reaction with metal ions particularly calcium. It is
a strong poison that weakens the central nervous system and causes a kidney malfunction
(Noon and Savage, 1999). When present in food, it reduces the bioavailability of calcium
and magnesium (Finar, 1973). However, the soluble part of the oxalate was reported to be
toxic above a concentration of 2-5g when consume in the food (Munro and Bassir, 1969).
Hydrocyanic acids are compounds released by plants such as legumes, tubers, cereals,
and roots particularly cassava upon enzymatic hydrolysis of plant compounds (Umar,
2005). The compounds comprises Limarin and Lotaustralin which form a complex with
Fe3+ cytochrome oxides system of aerobic organisms that results into death by cellular
anoxia (Hassan and Umar, 2004). Acute cyanide toxity was reported to have result to
death and chronic toxicity causes ataxic neurophathy and epidermic spastic paraparesis
(Ademoroti, 1996). Moreover, the high cases of mucous membranes skin nervous system
in Nigeria was linked to ingestion of high level of cyanide in a cassava- based diets
(Adindu et al., 2003).
Saponins are naturally occurring oily glycosides that foam when shaken with water.
These compounds reduced the palatability due to their bitter taste, and also served as antifeed
against microbes and fungi in plants which are non poisonous to warm blooded
animals, but are more dangerous when absorbed into the blood stream and quickly
38
haemolyse red blood cells (Applebaum et al., 1969). Acids as well as enzymatic
hydrolysis of saponing glycosides, produces sugar (usually, but not necessarily glucose)
and sapogenin (either triterpene or steroid). According to Abubakar, (2007) some sugars
and sponins are useful raw- materials in the steroid hormones synthesis.
Tannins are defined industrially as substances of plant origin which have the ability of
changing the animal skin into leather, due to their ability to cross link with proteins (Zaki,
2000). They are yellow-white to brown colour with an astringent bitter taste, containing
polyphenols that either bind and precipitate or shrink proteins. They are also
characterized as being non-crystals complex with high molecular weight (500-3000) that
normally form colloidal solutions in water, and are able to react with proteins to form a
co- polymers that are water-insoluble.(Barde, 2010).
1.4 Aim and objectives
The aim of this study was to analyze the nutritional and anti nutritional composition of
wild melon seed and seed oil.
The specific objectives were as follows;
i. To determine the essential food components present in the seed.
ii. To determine the mineral elements present in the seed.
iii. To investigate the amino acids content of the seed.
iv. To analyze the level of anti nutritional factors present in the seed
V. To determine the chemical properties of the seed oil.
Vi. To determine the fatty acid content of the seed oil.
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