Potentialities of newly isolated Bacillus subtilis and Lactobacillus sp for curd preparation and a comparative study of its physico-chemical parameters with other marketed curds.

ABSTRACT

Two Bacillus sp. were isolated from the local fermented milk and identified on the basis 16S rRNA sequence profile as Bacillus subtilis AKL1 and by biochemical process as Lactobacillus acidophilus AKL2. These isolates were used as fresh inoculums for curd preparation individually and in combinations. Different physico-chemical and therapeutic properties of the newly prepared curd were examined and compared with marketed local (sweet and sour) and branded (Mother Dairy and Thackar) curds. The total hydrolyzed peptides, free amino acids, lactic acid were significantly higher, whereas, total solid, ash content, syneresis and free reducing sugar were lower in the curd prepared by a mixture of AKL1 and AKL2 (0.50.5, v/v). The antioxidant activity against ABTS+, DPPH•, OH• and Fe3+ were also higher in the newly formulated curd. Polyphenols (85.5µg/g), flavonoids (12.5µg/g) and free aromatic amino acids contents were also higher in AKL1+AKL2. All these components prevent excess protein oxidation that was revealed by SDS-PAGE. The curd also exhibited potent antimicrobial activity against some entero-pathogens like Clostridium perfringens, Escherichia coli, Shigella dysentery, Vibrio cholerae and Staphylococcus aureus. It can be concluded that the combination of these Lactobacillus sp. will be a fruitful inoculum for the preparation of curd having better health promoting effects.