Evaluation of The Effects of Thermal Processing Treatments on The Nutrient and Anti-nutrient Composition of Pigeon Pea (Cajanus cajan) Seed Flours

Abstract

This study was carried out to evaluate the effects of thermal processing techniques on the nutrient and antinutrient contents of pigeon pea (Cajanus cajan) flours. The pigeon pea seeds were sorted, cleaned and divided into five equal lots of 0.5kg each. Four lots of pigeon pea seeds were processed into blanched, boiled, roasted, and autoclaved pigeon pea flours, while the fifth lot was processed raw and used as control. The raw and thermally processed samples obtained were analysed for nutrient and antinutrient composition using standard methods. The proximate composition of the samples showed that the flours had a range of 8.61 - 11.46 % moisture, 21.13 - 23.94 % crude protein, 1.26 - 1.68 % fat, 5.12 – 6.10 % crude fibre, 1.74 – 2.97 % ash, 55.56 – 60.41 % carbohydrate and 333.45 - 342.75 kJ/100g energy, respectively. The mineral composition showed that the flours contained 86.24 – 144.72 mg/100g calcium, 137.80 – 170.33 mg/100g magnesium, 125.86 - 156.76 mg/100g potassium, 66.66 – 95.62 mg/100g sodium, 4.38 – 6.64 mg/100g iron and 130.27 – 178.29 mg/100g phosphorus, respectively. The vitamin content of the flours were 3.09 - 4.33 mg/100g ascorbic acid, 0.05 - 0.17 mg/100g thiamine, 0.03 - 0.21 mg/100g riboflavin, 0.13 - 0.28 mg/100g niacin, 3.21 - 6.25 mg/100g vitamin A and 1.10 - 2.70 mg/100g vitamin E, respectively. The antinutrient composition of the flours also showed that the levels of trypsin inhibitor, tannin, phytate, oxalate, saponin and haemagglutinin ranged from, 2.30 – 5.61 Tiu/mg, 0.81 – 1.5mg/100g, 1.12 - 4.18mg/100g, 0.48-4.01 mg/100g, 1.28 – 3.66 mg/100g and 1.30 – 7.44 Hiu/g, respectively. Therefore, the study showed that thermally processed pigeon pea flours could be used as nutrient dense ingredients in the preparation of a wide range of foods for children, adolescents and aged adults especially in developing countries where the problems of protein-energy malnutrition and micronutrients deficiencies are prevalent than the raw sample.