Comparative Evaluation of Health-Promoting Compounds, Physicochemical and Microbiological Properties of Sorghum [Sorghum bicolor (L.) Moench] Based Mahewu Produced by Different Traditional Brewers in Thohoyandou, South Africa

Abstract

Sorghum (Sorghum bicolour (L.) Moench) is an emerging reliable alternative for mahewu production. The aim of this study was to evaluate the health-promoting compounds, physicochemical and microbiological properties of sorghum-based mahewu produced by different traditional brewers in Thohoyandou, South Africa. A total of 18 mahewu samples produced by six traditional brewers (TB1–TB6) were collected and compared for antioxidant, physicochemical, and microbiological properties. Commercial sorghum mahewu was used as a control sample. The total phenolic content of the mahewu samples varied from 27.37 to 65.89 GAE /g, with commercial mahewu having a lower value. The flavonoid content ranged from 0.18 to 0.30 GAE/g, and commercial mahewu had a higher value. The DPPH scavenging activity and FRAP of mahewu samples ranged from 44.62% to 49% and 1.47 to 2.36 mg GAE/g, respectively. Commercial mahewu had a higher DPPH value but a lower FRAP value. The pH of mahewu varied significantly, ranging from 3.38 to 3.66, but was within the acceptable range. The °Brix values varied from 9.68 to 17.49, with traditional mahewu samples having higher values than commercial mahewu. Total titratable acidity ranged from 0.63 to 1.17%. The viscosity ranged from 444.33 to 1297.00 cP, with commercial mahewu having a higher value. There was a significant variation in the color of the mahewu samples with respect to L*, a*, b*, C, Hue, and ΔΕ. The growth of yeasts and molds varied from 7.95 log10 to 8.99 log10 (cfu/mL) in traditional mahewu samples, and coliforms ranged from 3.68 to 5.96 log10 (cfu/mL) and were not isolated in commercial mahewu. The total plate count ranged from 7.914 to 8.978 log10 (cfu/mL). The microbiological results show that traditional brewers are meeting the legal limit and can increase their products for commercialization.