Effect of sorghum and maize malt particle size on physicochemical, stability, microbiological, and sensory characteristics of umqombothi

Abstract

The consumption of Umqombothi alcoholic beverages in South Africa is widespread in townships and rural areas. This study aimed to investigate the effect of sorghum and maize malt particle size on the physicochemical, microbiological, stability, and sensory characteristics of Umqombothi. Three different particle sizes were compared, namely control, coarse, and fine powder particle sizes. Subsamples were taken at the following stages, during the production of Umqombothi: first, second, third, fourth, and fifth. Lactic acid bacteria were significantly dominant, with 8.16, 7.11, and 5.91 log cfu/mL in the final product for the control, coarse, and fine powder particle sizes. The yeast counts were 3.3, 4.64, and 5.63 log cfu/mL for the control, coarse, and fine powder particle sizes. Molds were significantly reduced to non-detectable levels after the second fermentation and the total coliforms in the final product were reduced for all particle sizes. The total soluble solids significantly decreased in the second fermentation samples. The coarse particle size exhibited significantly higher alcohol and significantly lower pH levels, which are encouraging signs for improved quality and shelf life. Different particle sizes of sorghum and maize malt affect the quality of the finished product and the production method of umqombothi.