Effect of probiotic fermentation on physico-chemical and nutritional parameters of milk-cereal based composite substrate.

Abstract: A dairy-cereal based composite substrate was prepared from whey-skim milk (60:40 v/v), germinated pearl millet flour (4.73% w/v) and liquid barley malt extract (3.27% w/v) and fermented using probiotic strain Lactobacillus acidophilus NCDC-13. Probiotic fermentation increased whiteness index, viscosity and water holding capacity of unfermented substrate. Fermentation caused a reduction in total solids, fat, ash and total dietary fibre content and increment in protein content. Fermentation brought a highly significant reduction in phytic acid (78%) and polyphenol (46%) content. The protein and starch digestibility increased significantly. The HCl- extractability of Ca, Fe, Mg and Zn of unfermented substrate was 32%, 25%, 64% and 17% respectively, which increased to 73%, 50%, 83% and 65% respectively after fermentation. Fermentation resulted in 77% decrease in phytate P as % of total P and significant increase in free P. The current investigation revealed that probiotic fermentation improved nutritional attributes of the composite substrate substantially. The low cost nutritionally enriched probiotic substrate can be utilized for preparation of a wide range of low- cost probiotic foods to address malnutrition and enhance immunity of common population. © Association of Food Scientists & Technologists (India) 2021.