Production, nutritional and biological value of bambara groundnut (Vigna subterranea) milk and yoghurt

The purpose of this study was to assess the nutritional properties of Bambara milk and yoghurt. The milk was produced by aqueous extraction of flour obtained by dehulling the seeds followed by parboiling. It was then fermented using a mix culture of L. Bulgaricus, S. thermophilus and L. plantarum , followed by the evaluation of the protein biological value on rats. During the process of flour production, from the whole seeds to the flour, a significant drop in total polyphenol content (1.00 ± 0.10–0.41 ± 0.01 mg/100 g) and phytates (1.18 ± 0.03–0.32 ± 0.01 mg/100 g) was observed while the protein content increased (19.7 ± 1.2–25.47 ± 2.28 g/100 g). During the fermentation of the milk into yogurt, a significant decrease in phytate content (0.29 ± 0.01–0.03 ± 0.01 g/100 g), an increase in the protein content (1.8 ± 0.1–2.6 ± 0.1 g/100 g) and the protein digestibility (91.5–96%) were equally observed. Red blood cell, glycaemia, the ASAT and ALAT contents of rat bloods fed Bambara milk or yoghurt were not significantly different to rats fed casein as protein reference. In conclusion Bambara groundnut is a source of protein which the quality may be enhanced through processing of high value yogurt.