G Ojieh, O Oluba, Y Ogunlowo, K Adebisi, G Eidangbe, R Orole
amino acids, egusi melon, minerals, proximate composition, seed
G Ojieh, O Oluba, Y Ogunlowo, K Adebisi, G Eidangbe, R Orole. Compositional Studies of Citrullus lanatus (Egusi melon) Seed. The Internet Journal of Nutrition and Wellness. 2007 Volume 6 Number 1.
Proximate, amino acid and mineral composition of Citrullus lanatus (egusi melon) flour were determined using standard analytical procedures. The proximate composition analysis of egusi melon showed that the seed contained (% dry weight): moisture (4.6±0.3), ash (3.7±0.1), ether extract (45.7±0.1), crude protein (23.4±0.2), crude fibre (12.0±0.1) and total carbohydrate (10.6±0.2). The result of the amino acid analysis showed that egusi melon seed contained good quantities (g/100g protein) of arginine (9.0), isoluecine (4.8), leucine (4.2), and phenylalanine (3.2) which are essential amino acids as well as glutamic acid (16.9) and aspartic acid (16.3).The mineral analysis (mg/100g) of the flour included: Na (13.0±0.2), K (96.1±0.4), Ca (28.2±0.2), Mg (31.4±0.2), Mn (1.7±0.1), Cu (0.4±0.1), Zn (1.2±0.1), Fe (1.3±0.2), and P (125.3±3.1). With this nutrient profile egusi melon compares favourably with the known protein rich foods such as soybean, cowpeas, pigeon peas and pumpkin.
Many plant proteins usually in the form of protein extracts or seed flours are being investigated and tested for new products such as low cost fabricated foods which are nutritious, attractive and acceptable to consumers just like conventional foods from meat, fish and dairy products (Lawhom and Cater, 1971; Lin
Comprising 50% oil and 35% protein (Jack, 1972), the seeds have both nutritional and cosmetic importance. The seeds contain vitamin C and B2, minerals, riboflavin, fat, carbohydrates and protein (Lazos, 1986). Despite the vast nutritional and medicinal significance of egusi melon, little detail on its amino acid and mineral composition is available to an international readership. This study is therefore aimed at investigating the proximate, amino acid and mineral composition of egusi melon seed flour obtained from a South- Western State of Nigeria . Such information may expand the scope of knowledge on the nutritional qualities and utilization of egusi melon flour outside the coast of West Africa .
Materials and Methods
The filtrate evaporated to dryness at 40 ° C under vacuum in a rotary evaporator. Residue was dissolved with acetate buffer (pH 2). The method of amino acid analysis was by ion exchange chromatography (FAO/WHO, 1991) using the Technicum Sequential Multi Sample Amino Acid Analyzer (TSM) (Technicum Instruments Corporation, New York ).
Results and Discussion
The proximate composition (on dry weight basis) of Citrullus lanatus (egusi melon) are as shown in Table 1. According to the results, the moisture content of egusi melon (4.6%) is low compared to those reported for legumes by Arkroyed and Doughty (1964) ranging between 7.0 and 10%. However, this value agrees closely with that reported earlier by Ige
The amino acid analysis of egusi melon flour (g/100 g protein) is shown in Table 2. The results show that arginine, glutamic acic and aspartic acid with 9.0, 16.9, and 16.3 g/100g protein respectively were the three most abundant amino acids in egusi melon. This observation is in close agreement with the report of Olaofe
The results obtained for the mineral composition of egusi melon are shown in Table 3. From the results, P is the predominant mineral in egusi melon seed. This is not in agreement with the observations of Olaofe and Sanni (1988), and Aremu et al. (2005) that K was the most abundant mineral in Nigerian Agricultural products. K however ranked second in concentration to P in egusi melon as observed in this study. Na, Ca and Mg are other important minerals which are highly concentrated in egusi melon. The Na/K ratio of egusi melon is less than one. This, on the basis of the recommendation of Nieman et al. 1992) could suggest that egusi melon would be suitable for reducing high blood pressure. On the other hand, the Ca/P ratio of egusi melon is far less than one (0.2) thus its consumption is likely to reduce the intestinal absorption of calcium.