Proximate, Mineral and Anti-nutrient Composition of Pumpkin (Cucurbitapepo L) Seeds Extract

Pumpkin seeds were analysed for their nutritional and anti-nutrit ional composition, the results obtained were; moisture content (5.00%), ash (5.50%), crude lipid (38.00%, crude fibre (1.00%), crude protein (27.48%), Available carbohydrate (28.03%) and calorific value (564kcal/100g). Elemental analysis shows that potassium is the most abundant element in the sample (273mg/100g) and manganese is least (0.06mg/100g).The anti-nutritional parameters analysed are; phytate (35.06 mg/100g), oxalate (0.02±0.10mg/100g), hydrocyanic acid content (0.22±0.04mg/100g) and nitrate (2.27±002mg/100g). The result shows that the pumpkin seeds if properly utilized can serve as good source of minerals.


Introduction
Fro m the family Cucurbitaceae, is Cucurbita pepo, (Co mmon name: Pu mp kin; Yoruba: Elegede), a mediu m sized plant grown for its Fruits and edible seeds. Hence, it is known to be used as food and in herbal formu lation in Nigeria.The ways of expanding the use of available local food sources are increasingly pursued, some o f these local food sources contain seeds, many reports on some lesser known seeds and fruits indicated that they could be good sources of nutrients for both man and livestock [1].
Seeds are good sources of protein, fats, carbohydrate and minerals [2].
Researches have shown that seeds not only contain nutritionally important bio-compounds but are also sources of other phyto-compounds which at certain critical levels have significant anti-nutrit ional effects [3]. These compounds include oxalate, phytate, nitrate, cyanide etc.
Pump kin has received considerable attention in recent years because of the nutritional and health protective values of the seeds .Pump kin seeds are consume directly as snack food in many cultures throughout the world [4].
Pu mp kin p lan t is an ann ual p lant with leafy g reen vegetable; it has a climb ing stem of up to 12m long and fruit with a round fibrous flesh [4]. Pu mp kin fruits are variab le in size, colour, shape and weight; they have a moderately hard flesh with a thick ed ible flesh below and a central cavity containing the seeds. The seeds are covered with a testa which serves as a protectant around it.
More analysis on Pumpkin seeds will only increase the available data on their nutritional and anti-nutritional composition. However, little work has been reported on the mineral co mposition of pu mpkin seeds varieties fro m Tudunwada area, Kaduna Nigeria, an area known for h ighly condensed industries including petrochemicals. Therefore, the main objective of the present study was to evaluate the proximate, minerals, nutrit ional and anti-nutrit ional composition of Pu mpkin seeds as potential source of minerals as well as their calorific value and their health implications.

Materials and Methods
Ripped fruits of cucurbita pepo L were obtained fro m different farm locations in Tudunwada area, Kaduna Nigeria. The samples were mixed together andrepresentative samples were picked at random [5].The fresh fruits were authenticated at the Herbariu m unitof the depart ment of Bio logical Science of Us man Danfodio Un iversity Sokoto, Nigeria. The samp le fruits were clean with water and rinsed with distilled water to avoid surface contamination [6]. The flesh of the fruit and the seeds were separated using plastic spoon after dividing the fruit into two. The sample was dried at room temperature, crushed to a fine powder using mortar and pestle, sieved through 20-mesh and stored in an air tight plastic container for analysis.

Proxi mate Analysis
Moisture content was determined at 105 o C. Ash content was determined at 550 o C. Crude protein, lipid and fibre were also determined according to the procedures of [7]

Crude Nitrogen
Crude Nitrogen was determined based on the Kjeldhal procedure and crude protein value was obtained by mu ltip lying the nitrogen value by a factor of 6.25 wh ile estimation of available carbohydrate was done by difference as: CHO = 100 -(%ash+%crude protein+%crude lip id+%fibre) Energy (kcal) =[(%CHO x 4) + (%CP x 4) + (CL x 9)] Where CHO, CP and CL stands for carbohydrate, crude protein and crude lipid respectively [8].

Mineral Anal ysis
The sample was digested into solution by wet digestion using a mixture of conc. Nitric, perch loric and sulphuric acids in the rat io 9:2:1 respectively. Fe, Zn, Co, Mg, Ca and Mn were determined by AAS, (Alpha 4 model, Buck Scientific Ltd USA). While Na and K were determined using atomic emission spectrometer (200-A model, Buck Scientific Ltd UK), and colorimetric method was used to determined Phosphorus.
Other analysis and adopted methods include the determination of o xalate, phytate and hydrocyanic acid [7] and nitrate [9].

Proxi mate Composition
The result showed that the seed has moisture content of 5.00 % wh ich is lower than those of vegetable spaghetti seed 45.67±2.03 [10] and gardenia aqualla seed 49.00 [10]. The lower mo isture content of the seed will give it a storage advantage The ash content of the seed is 5.50 %. Which is close to that of gardenia aqualla seeds 5.20% [14]. The percentage ash of the sample gave an idea on the inorganic content of the samples fro m where the mineral content could be obtained. The ash content obtained is similar to the range of 1.63-8.53% reported for co mmonly consumed fru its by [11].Samp le with high ash contents is expected to have high concentration of various mineral elements, which are expected to speed up metabolic processes, improve growth and development.
The crude lipid content of the seed is within the range of 38.00% this could be classified as an oil seed like groundnut, melon e.t.c. Lipids are essential because they provide the body with maximu m energy [11].
The fib re content of the seeds is 1.0 % which co mpared favourably with that of Gardenia aqualla seeds [9]. Although, fibre containing food are known to expand the inside walls of the colon, easing the passage of waste, thus making it an effective anti-constipation, it lowers cholesterol level in the blood and reduce the risk of various cancers. But emphasis has been placed on the importance of keeping fibre intake low in the nutrition of infants and weaning children because high fibre levels in weaning diet can lead to irritation of the gut mucosa [2]. It also enhances gut perturbation in young animals (e.g. p iglets and chickens) [12]. Co mparatively, the fibre content of the seed is close to 1.23± 0.03 % as reported for Arthocarpusheterophyllus seed [2] The protein content of the seed was found to be 27.48% which shows that the seed can serve as a source of protein considering the level o f protein deficiency in the society.
The available carbohydrate content of the seed is found to be 28.03%. The sample could not be considered as potential source of carbohydrate when compared to the content of some conventional sources like cereals with 72-90 g/100g Carbohydrate [13].

Elemental Anal ysis
Potassium is the most abundant element found in the seed (273mg/ 100g), High amount of potassium in the body was reported to increase iron utilization [14] and beneficial to people taking d iuretics to control hypertension and suffer fro m excessive excret ion of potassium through the body flu id [15].
The concentration of sodium in samp le is 170 mg / 100g; this element is required by the body to regulate blood pressure and blood volume. It helps regulate the fluid balance in the body; it also helps in the proper functioning of the muscles and nerves [16].
The calciu m content of the sample was found to be 9.78mg/ 100g Calciu m helps to ease insomnia and helps regulate the passage of nutrients through cell walls, without calciu m the muscles in the body cannot contract correctly, the blood in the body will not clot and the nerves will not carry message. If the body don't get enough calciu m fro m the food we eat. The body automatically takes the calciu m needed from the bones. If the body continue to tear down more Calciu m than it replaces over a period of years the bones will beco me weak and break easily [ 16] (Payne, 1990). Calciu m ions are also necessary for the normal functioning of nerves and muscles [17].
The concentration of Magnesium in the samp le is 67.41±0.05mg/100g Magnesium is a constituent of bone and teeth and is closely associated with calciu m and phosphorus. Magnesium is necessary for the release of parathyroid hormone and for its action in the backbone, kidney and intestine and for the reactions involve in converting vitamin D to its active form. Magnesium is important in t issue respiration, especially in o xidative phosphorylation leading to format ion of Adenosine triphosphate (ATP). It is also involved in normal muscular contraction; calciu m stimu lates muscles while magnesium relaxes the muscles [18]. Magnesium deficiency results in uncontrollable twisting of muscles leading to convulsion and tetanus, which may both lead to death [17].
The concentration of Phosphorus in the sample was estimated as 47.68±0.04mg/100g, phosphorus is found bound in the blood and cells, wh ile most of the non-skeletal phosphorus is inorganic in the form of nucleic acids, phosphor-lipids, ATP and sugar phosphate [ 16] (Payne, 1990). Phosphates play important roles as buffers that prevent change in the acidity of body fluids because of their ability to combine with additional hydrogen ion. The combination with phosphorus makes it possible for nutrients to cross the cell membrane [18].
This work gave Iron content of 3.75±0.02mg/ 100g, Iron performs several functions in the body; it helps in the formation o f b lood, it also helps in the transfer of o xygen and carbon dioxide fro m one tissue to another [18].
Iron deficiency results in anaemia which impairs muscles metabolism, iron deficiency in children result in impaired learning ability and behavioural problems [19].
The concentration of Cobalt in sample was found to be 2.17±0.02mg/100g, Cobalt p lays a role in the metabolis m of vitamin B-12 hence, increase body ability in its absorption. Cobalt is believed to function as an activating ion in so me enzy mes [19].
Manganese was found to be the least among all the minerals analysed in this sample (0.06±0.01mg/ 100g). Manganese plays an important role in all mental functions and aids in the transfer of o xygen fro m lungs to cells, it is important as an activator for enzy me reactions concerned with carbohydrate, fat and protein metabolis m [16].
Manganese deficiency is rarely observed owing to the large amount of it in hu man diet, but in a situation where the deficiency occur it leads to retardation of growth and skeletal abnormalities. Too much accu mulat ion of manganese is toxic in the blood and is mostly associated with weakness of the body and psychological and nervous system d ifficu lties. Toxicity of manganese however occurs more often with iron deficiency [19].
Pump kinseed presented fairly h igh value for Zinc (14.14±0.02mg/ 100g). Zinc is known for boosting the health of our hair, it is believed to play a role in the proper functioning of some sense organs such as ability to tastes, sense and smell [16]. Zinc plays a very important role in protein and carbohydrate metabolism and also help in mobilizing vitamin A fro m its storage site in the liver and facilitates the synthesis of DNA and RNA necessary for cell production [18].

Antinutritional Composition
The concentration of oxalate found in the seed is 0.023mg/100g which is not high. High oxalate diet can increase the risk of renal calciu m absorption and has been implicated as a source of kidney stones [20]. The level of oxalate in the sample is not high to pose any health treat.
The phytate content (35.06±1.10mg/ 100) of the seed is lower than that of Dannielleaoliveri kernel seed 51.05 mg/100g [8],but higher than that of Jatrophacurcas kernel seed 34.37 mg/100g [21]. The problem with phytate in food is that it can b ind some essential mineral nutrients in the digestive tract and can result in mineral deficiencies [2]. The phytate composition of the sample might not pose any health hazard when co mpared to a phytate diet of 10-60mg/g which if consumed over a long period of t ime that has been reported to decrease bioavailability of minerals in monogastric animals [22].
The concentration of Hydrocyanic acid in the seed is 0.22mg/ 100g this shows that the level of the acid in the sample is within the acceptable range for hu man consumption. Only p lants with mo re than 200 mg of hydrocyanic acid equivalent per 100 mg fresh weight are considered dangerous [23]. Consumption of high levels of Cyanide is associated with a serious health problem, a neurological disease known as Tropical Ataxis Neu rophathy (TAN) was lin ked to consumption of high level of cyanide in cassava based diet [24].
The concentration of nitrate in the seed is 2.27 mg/ 100g. These values are within the acceptable daily intake of 3.7 mg/kg body weight (WHO). Higher concentration of n itrate in the food can lead to a disease called methemoglobianaemia which is known to reduce the ability of red blood cells to carry o xygen [25].
It should be noteworthy that in addition to the importance of Pu mp kin (Cucurbita pepo) arrayed in this work, the seed has also received considerable attention in recent years an excellent source of protein and also has pharmacological activities such as anti-diabetic, antifungal , antibacterial and anti-inflammation, activ ities and antioxidant effects [26].

Conclusions
It can be concluded that the seed is a good source of some protein and oil. Fro m the highlights of the present study, we can also deduce that, these seeds may serve as constituents of minerals to animal and human through dieting. Generally, results and findings from this research agreed favourably with those of other wild plants recommended as food supplement in literature.