Development of coconut water-based exopolysaccharide rich functional beverage by fermentation with probiotic Lactobacillus plantarum SVP2

Abstract

Most of the probiotic functional beverages are dairy based and cannot be consumed by lactose intolerant people. In this study, growth of probiotic Lactobacillus plantarum SVP2 and its exopolysaccharide (EPS) production was studied in natural sources such as coconut water and sugar cane juice with soyabean and green gram extracts as protein sources. Among four combinations tested, highest growth (18.74 ± 0.33 g/L) and EPS (11.89 ± 0.42 g/L) was achieved in coconut water based medium supplemented with soyabean protein (0.25 g/L) and sucrose (10 g/L). Therefore, EPS production by L. plantarum SVP2 was optimized in coconut water-soyabean protein medium by one factor at a time (OFAT) analysis considering factors such as concentrations of sucrose, soyabean protein and inoculum, temperature, agitation speed and fermentation time. The fermented functional beverage was prepared by supplementing coconut water with 40 g/L sucrose, 0.75 g/L soyabean protein, 1.5% v/v inoculum at 27 °C, 100 RPM for 36 h (optimized conditions) during which maximum EPS of 64.17 ± 0.61 g/L was produced. The cell count, pH and EPS amount in fermented beverage remained almost similar on storage of product in refrigerated conditions for 7 days. Although, sensory analysis performed on synthesized beverage and beverage stored at refrigerated conditions revealed moderately high acceptance of flavour and texture, overall acceptability among consumers was average attributing to colour and slightly sour fermented odour. Consumption of this fermented functional beverage offers multiple benefits owing to antibacterial, anti-biofilm properties of EPS and probiotic L plantarum. • Highest growth and EPS production by L. plantarum SVP1 in coconut-water - soyabean protein medium. • Maximum EPS (64.17 ± 0.61 g/L) at 40 g/L sucrose, 0.75 g/L soyabean protein, 1.5% v/v inoculum at 27 °C, 100 RPM in 36 h. • Sensory analysis revealed moderate acceptance of flavour and texture. • First report on antibacterial EPS enriched fermented coconut-water based beverage.