Effect of NPK Fertilizer on Chemical Composition of Pumpkin (Cucurbita pepoLinn.) Seeds

F. M. Oloyede,G. O. Agbaje,I. O. Obisesan,E. M. Obuotor

doi:10.1100/2012/808196

Abstract

An investigation of the proximate composition and antioxidant profile of pumpkin seeds obtained from different levels of NPK 15 : 15 : 15 compound fertilizer application at the Obafemi Awolowo University, Ile-Ife, Nigeria was carried out. Pumpkin seeds were grown in 2010 for two cropping seasons (May to August and August to November), and the following fertilizer rates were applied: 0, 50, 100, 150, 200, and 250 kg/ha. Standard analytical methods were used to determine protein, crude fibre, ash, fat, carbohydrate, antioxidant activities, phenol, flavonoid, proanthocyanidin, and anthocyanin. The highest concentrations of the proximate and antioxidants analysed were found from the seeds of control and those treated with lower NPK rates. The mean protein, ash, crude fibre, and carbohydrate values of pumpkin seeds at zero to 100 kg NPK/ha were 27%, 1.56%, 0.56%, and 11.7% respectively. At these same levels of fertilizer, pumpkin seed oil yield was 59%. Antioxidant activities ranged from 89.9 to 90.4% while total phenol was 47 mg/100 g. Except for carbohydrate, the % concentration of nutrients and antioxidants in pumpkin seeds was significantly (P = 0.05) depressed with fertilizer rates above 100 g/ha.

Highlights

Pumpkin seed vegetable is valued in many countries such as Japan, Czech Republic, Hungary, Germany, Austria, Romania, Italy, and West and South Ukraine
The protein, fat, ash, crude fibre, and carbohydrate in pumpkin seeds were significantly influenced by season and fertilizer
Fertilizer influence showed that proximate values of protein, fat, ash, and crude fibre in pumpkin seeds were similar at 0, 50 and 100 kg NPK/ha

Summary

Introduction

Pumpkin seed vegetable is valued in many countries such as Japan, Czech Republic, Hungary, Germany, Austria, Romania, Italy, and West and South Ukraine. The seeds are a good raw material for the production of oil used in food preparation and in medicine [1, 2]. The seed oil is rich in glycerides of linoleic, oleinic, palmitin, and stearine acids. Omega-3 fatty acid was found to be present in pumpkin seeds; it helps to prevent artheriosclerosis, high blood pressure, and heart diseases; it stimulates metabolism of accumulated fats. Oil-cake fats from pumpkin seeds contain large amounts of (almost 60%) of omega-3 acids twice that of cod liver oil [3,4,5,6]. Pumpkin seed powder is used in China and the United States as an ingredient of salad dressings and in baked products. The seed is used medicinally in the prevention of kidney stones. In Mauritius an infusion of the seeds is used internally to treat hypertension and prostate complaints and externally to treat erysipelas [7]

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