Effect of Processing on the Nutrient, Anti-nutrient and Functional Properties of Mucuna flagellipes (Ox-eyed Bean) Seed Flour; An Underutilized Legume in Nigeria

Abstract

The promotion and consumption of underutilized legumes could help mitigate food insecurity and alleviate malnutrition in developing countries. In this study, the effect of processing on the nutritional, anti-nutritional and functional properties of Mucuna flagellipes seed flour was determined. The proximate composition of the samples showed that the flours had a range of 7.37 to 11.46 % moisture, 18.21 to 28.53% crude protein, 2.93 to 3.97% fat, 8.06 to 12.90% crude fibre, 2.74 to 4.69% ash, 38.45 to 59.09% carbohydrate, and 1446.34 to 1285.43KJ/100g energy. Profile of the amino acid showed that the lysine, leucine, tryptophan and aspartic acid in the unprocessed flour were significantly (P ≤ 0.05) reduced by roasting. The vitamin composition of the samples showed that vitamin A, vitamin C and vitamin E varied between; 0.15 to 3.46 mg/100g, 0.03 to 85.54 mg/100g, 3.41 to 14.24mg/100g respectively. The mineral composition of the flours showed that the calcium, potassium, phosphorus, magnesium, iron and zinc contents of the samples varied between 132.02 to 167.00mg/100g, 85.91 to 145.00mg/100g, 80.95 to 132.87mg/100g; 83.74 to 145.19mg/100g, 19.90 to 33.16mg/100g and 3.96 to 6.26mg/100g, respectively. The following mineral ratios were lower than the reference balance (ideal) and also lower than the minimum in the acceptable ideal range: Ca/Mg, Ca/K, Ca/P and [K ⁄(Ca+Mg)] for all the seed flours except for Ca/P mineral ratio whose value for the roasted seed flour falls within the acceptable ideal range. The mineral safety index showed that Ca, Mg, P and Zn were all lower than the standards for all the seed flours, whereas Fe was higher than the standard in all the seed flour. The anti-nutritional factors of the samples were significantly (P ≤ 0.05) reduced by autoclaving and roasting than by boiling and soaking methods. The calculated molar ratios of phytate:calcium, phytate:iron, phytate:zinc, oxalate:calcium and [Phytate][Calcium]/[Zinc] were below the critical value and this indicate that the bioavailability of calcium, iron, and zinc in the raw and processed seed flour could be high. The nutrient composition of the flour suggests that it has the potential to be used as both nutritional supplements and functional ingredients in the preparation of a number of baked and complementary food products.