The Effects of Dehulling and Sprouting on Mineral and Vitamins Contents of Okpa Prepared from Three Bambara Groundnut (Vigna subterranea) Varieties

Abstract

Okpa is a traditional steamed snack prepared from milled Bambara groundnut flour. It serves as a staple among the Igbos of south-east Nigeria. This study was carried out to investigate the effects of sprouting and dehulling on the minerals and vitamins contents of Okpa snacks prepared from three different BGN types namely: cream, black and red. The samples were collected directly from Maiduguri Monday Market in Borno State, Nigeria. All the experiments were conducted in the Food Science and Technology Laboratory, University of Maiduguri. The sprouting and dehulling processes were carried out at room temperatures prior to their milling into flours all the analyses. Atomic Absorption Spectrophotometer (AAS) was used in the quantification of calcium, magnesium, iron and zinc, while Flame Photometer was used to quantify potassium and sodium, and a High-Performance Liquid Chromatography (HPLC) was used in the determination of vitamins B1, B2 and B6. The results of the Sprouting resulted in decrease in the Ca, Na and Fe contents of the flours (0.09-0.49, 3.02- 8.67, 0.41- 0.99 mg/kg respectively) while the Okpa produced from the black and red varieties of bambara groundnut, resulted in an increase in only the Mg content of Okpa produced from the black variety (19.98 mg/100kg). Similarly, dehulling resulted to decrease in the K and Zn contents of both the flour and Okpa produced from the red variety, and an increase in the Mg contents of the cream BGN flour and Okpa samples. From the results, dehulling generally decreased the B-vitamins contents of all the BGN varieties analyzed. Therefore, it would be worthwhile to conduct further studies examining the effects of cooking time and temperature on Okpa to assess the retention of vitamin contents, particularly water-soluble vitamins like B1, B2, B6. Exploring the impact of cooking conditions on these vitamins could provide valuable insights into optimizing nutritional outcomes in Okpa preparation.