Abstract:
Bambara groundnut (BG) (Vigna subterranean) is an underutilized,
indigenous crop in South Africa that has nutritional and associated health
benefits. Decreasing the antinutrients in food sources can potentially increase
the digestibility of proteins and mineral absorption. To determine the effect of
traditional processing (cooking) on the antinutrient content and metabolome
of this crop, BG was sampled from 12 rural farms in three districts of the
Mpumalanga province, South Africa. The four main colors that were identified
(cream, orange, brown, and purple) were pooled together according to the district
they were obtained from. One-half of each color sample obtained fromeach
of the three districts was dehulled, color sorted, milled, and subjected to subsequent
antinutrient and metabolome analyses, while the other half was cooked,
air-dried, and milled prior to analyses. Samples were analyzed for phytate
and tannins (antinutrients) by hydrochloric acid extraction methods as well as
metabolome constituents by ultraperformance liquid chromatography coupled
with quadrupole time-of-flight mass spectrometry (UPLC–QTOF-MS). Phytate,
tannins, as well as other metabolomic constituents, namely, catechin, epicatechin,
procyanidin, as well as citric acid, were identified in all raw and cooked
BG samples. The cooking process resulted in a significant decrease (p < 0.05) in
the phytate and tannin content as well as an increase in the health-associated
phenolic compounds.
