The present study aimed to screen the indigenous probiotic cultures for their effect on total phenolic contents (TPC) and associated antioxidant activities in synbiotic fermented soymilk during storage. Among 16 cultures, subtractive screening was conducted based on different tests such as acidification rate and proliferation of lactic acid bacteria (LAB) on supplementation of inulin (0-20 mM) and fructooligosaccharide (0-0.45 mM). Lactobacillus paracasei CD4 was selected as potential strain after principal component analysis (PCA) of different strains with prebiotic substrates at different concentrations. The strain was used for production of synbiotic soymilk product containing 10 mM inulin. The storage study was conducted at 4 °C for 21 days. During storage, the pH, titratable acidity, TPC, antioxidant activities, and viable cell counts (VCC) were determined. The fermentation of soymilk supplemented with 10 mM inulin did not alter the VCC; however, a decrease in pH and TPC and an increase in acidity and antioxidant activity were observed (p < 0.05). In conclusion, the synbiotic supplementation of inulin in soymilk enhanced the viability of Lactobacillus paracasei CD4 and antioxidant activity during storage under refrigeration conditions.
Keywords: Antioxidant activity; Prebiotic; Principal component analysis; Probiotic.