Microbiological quality, proximate composition and in vitro starch/protein digestibility of Sorghum bicolor flour fermented with lactic acid bacteria consortia

Abstract

Background: This study evaluated the effect of lactic acid bacteria (LAB) consortium fermentation on proximate and in vitro starch and protein digestibility of sorghum flour using standard techniques at 12-h intervals. Lactic acid bacteria previously isolated from fermenting maize and sorghum were combined as follows: Lactobacillus nantensis LP33 + Lactobacillus plantarum WCFS1 + Lactobacillus fermentum CIP102980 + Lactobacillus rhamnosus GG ATCC53/03 + Lactobacillus reuteri DSM20016 and Lactobacillus fermentum CIP102980 + Lactobacillus brevis ATCC14869 + Lactobacillus nantensis LP33 + Pediococcus acidilactici DSM20284 + Lactobacillus plantarum WCFS1 for consortium from maize and sorghum, respectively, and used to ferment sorghum flour. The flour was also fermented spontaneously for comparison. Results: The result showed significant (p < 0.05) increase in moisture, ash and protein contents; while fiber, lipid and carbohydrate contents decreased with increasing fermentation time in all set-ups. The in vitro protein digestibility increased significantly (p < 0.05) from 63.68 ± 1.46 to 79.89 ± 1.14%, 63.68 ± 1.46 to 83.72 ± 2.08% and 63.68 ± 1.46 to 84.28 ± 2.16% for naturally, LAB consortium from maize-fermented and LAB consortium from sorghum-fermented samples, respectively. Total viable count and total lactic acid bacteria count increased with fermentation with no coliform and fungal count in the consortia-fermented sample. The occurrence of isolates showed that only starter organisms were isolated from the consortia fermentations. Conclusion: This study has shown the effectiveness of LAB consortium fermentation in improving the nutritional quality and in vitro starch/protein digestibility of sorghum flour which holds potential in food fortification by food industries.[Figure not available: see fulltext.].