Development of Synbiotic Beverage Through Co-Culture Fermentation of Oat and Barley

Abstract

The objective of the present study was to isolate Bifidobacterium longum from infant faeces and elucidate its probiotic potential cereals based synbiotic beverage. B. longum BL-05 was isolated, characterized and encapsulated by using whey protein concentrate (WPC) and pectin (PE) as wall materials. Five bead formulations were prepared E1) 100% WPC, E2) 75% WPC + 25% PE, E3) 50% WPC + 50% PE, E4) 75% WPC + 25% PE and E5) 100% PE. The encapsulation was carried out by using extrusion method. The survival and viability of free and encapsulated B. longum was assessed through their resistance to Simulated Gastric Juice (SGJ), tolerance to bile salt, release profile in Simulated Intestinal Fluid (SIF) and storage stability during 28 days at 4oC. The microencapsulation provided better protection to B. longum BL-05 and encapsulated cells exhibited significant (p<0.05) resistance to SGJ and SIF as compared to free cells. E3 and E4 beads indicated more resistance to SGJ (at pH 2 for 2 h) and bile salts solution (2%) but comparatively slow release as compared to other bead formulations. Free cells lost their viability and exhibited sensitivity to gastrointestinal conditions whereas the viable cell count was > 6 log CFU/mL in all the encapsulated treatments. Additionally, free cells were not viable when stored at 4oC but microencapsulated cells revealed promising results during 28 days of storage at 4oC. Encapsulation efficiency, yield, size and textural properties (hardness, cohesiveness, springiness) of beads significantly increased as pectin proportion and total polymer concentration increased. SEM results revealed that E4 and E5 microbeads surface was more smooth and without visible wrinkles/shrinkage as compared to rest of bead formulations. On the basis of higher encapsulation efficiency and survival of B. longum BL-05, beads prepared with 75% WPC and 25% PE were selected for the development of oat and barley based synbiotic beverage with the addition of Lactobacillus plantarum as a co-culture. Significant variation was observed in physicochemical and microbiological analyses among treatments during 28 days of storage. Storage studies revealed a decreasing trend for pH, total soluble solids (TSS), vitamin C, water holding capacity (WHC), total phenolic content (TPC), antioxidant activity, viable cell count and sugars (glucose, fructose, maltose) while increasing trend was observed in acidity and organic acids (lactic acid, acetic acid). On the basis of overall acceptability, beverage developed with 50% oat and 50% barley were assigned highest scores by the panelists. The results established that extrusion using WPC and PE as encapsulating materials could be considered as one of the auspicious encapsulating materials for effective delivery of probiotics in food system. Combination of wall material showed a important strategy to improve the survival and viability of probiotics. Morover, utilization of oat and barley as prebiotics further enlightened the concept of synbiotic cereal base food products in the market.