Use of Selected Bacillus spp. Strains for Directed Fermentation of Hibiscus sabdariffa Seeds into Mbuja

Abstract

This work aimed at developing starter cultures for fermenting Hibiscus sabdariffa seeds into the traditional condiment Mbuja. In this context, two Bacillus amyloliquefaciens S1 and S5 and one Bacillus subtilis S12 strains, which had been selected in previous studies, were used separately and in combination (S5/S12) to produce Mbuja. The microbiological changes in fermenting seeds, as well as the physicochemical characteristics of the different obtained Mbuja, were evaluated. A sensory analysis was finally carried out to assess the organoleptic quality of laboratory-scale Mbuja compared to the most and the less appreciated products from traditional and spontaneous fermentation. Variable growth ability was noted for the tested starters. The combination of B. amyloliquefaciens S5 and B. subtilis S12 grew to the highest cell population of the end-product. Nutrients were globally affected by fermentation and were either increased (proteins, ash, and fats) or reduced (carbohydrates, crude fibers). Phytochemicals with potential positive impact on human health were detected and increased by the fermentation process. From the organoleptic point of view, Mbuja fermented with the combination S5 & S12 was the most appreciated by the hedonic panel, appreciation being driven by the taste and flavour of the product which was very close to that of the reference Mbuja.