Impact of LAB Fermentation on the Nutrient Content, Amino Acid Profile, and Estimated Glycemic Index of Sorghum, Pearl Millet, and Kodo Millet.

INTRODUCTION: Millets, owing to their rich nutritional and low-to-moderate glycemic index values, are termed superfoods; however, some anti-nutritional factors, such as tannins, limit the absorption of micro and macronutrients. Non-thermal processing technologies, such as fermentation, can improve nutrient content and reduce these anti-nutritional factors. METHODS: The effect of a controlled submerged fermentation of whole grain sorghum, pearl millet, and dehusked Kodo millet using mixed lactic acid bacteria (LAB) culture in tofu whey-based media on the proximate, antioxidant, tannin content, vitamin B, amino acids profile and estimated glycemic index (eGI) of different millets were evaluated. RESULTS: The protein content (2-12.5%), carbohydrate content (2-13.6%), antioxidant activity (3-49%), vitamin B complex, amino acid profile (89-90%), and eGI of whole grain sorghum, pearl millet, and dehusked Kodo millet improved due to LAB-assisted submerged fermentation. In contrast, fat (4-15%), ash (56-67%), crude fiber (5-34%), minerals, tannin and resistant starch content decreased due to LAB fermentation. CONCLUSION: Controlled LAB fermentation can improve the nutritional quality of sorghum and millets while reducing anti-nutritional factors. This non-thermal process can be adopted industrially to produce more palatable and nutritionally superior millet products.

Effect of different processing conditions on proximate composition, anti-oxidants, anti-nutrients and amino acid profile of grain sorghum.

The effect of different processing conditions (B: boiling; F: LAB fermentation; FS: fermentation and steaming; FSF: fermentation, steaming, flaking) of whole grain sorghum on the proximate composition, antioxidants, anti-nutrients, and amino acids (AAs) was evaluated. A marginal increase in the protein content and a decrease in the fat content was observed in the F-sample. Total phenolics reduced by 28%; DPPH scavenging activity and CUPRAC activity increased by 1.4 and 6 times, respectively during fermentation. Tannin content reduced by 30-39%, for the F, FS and FSF samples; highest reduction in trypsin inhibitory activity (58%) was observed in the FS-sample. Total AAs increased by 2.9 folds in FSF samples. Grain sorghum contained mostly hydrophobic AAs (30-34%). The ratio of Essential amino acid to total amino acid and predicted protein efficiency ratio were highest in the F-sample, whereas predicted biological value of the FSF was 3 times than that of the control.