The potential use of aby-6 starter culture in fermentation of soy based substrates

Abstract

The aim of this study was selection of optimal fermentation parameters (inoculum level and temperature) for production of fermented soy milk based beverage, using starter culture ABY-6 specially designed for yogurt production. Samples inoculated with five different inoculum levels (0.05; 0.1; 0.2; 0.3; 0.4; 0.5%) were fermented at 39, 42 and 45 0C. After 6h of fermentation, quality of fermented soy milk based beverages was evaluated by determining the viable cell count, pH value, titratable acidity, proteolytic activity and α-amino acid content. Based on the results all samples reached pH values in range 4.70-5.15 and titratable acidity in range 15.6-24.4 0 SH. Highest viable cell count (9,08 log (CFU ml-1 )) was obtained in sample inoculated with 0.5% (w/v) of starter culture, fermented at 42 0C. After 6h of fermentation, in samples with highest viable cell count, proteolytic activity (538.46 µgLe/ml) and free α-amino acid content (249.54 mg/ml) were determined. The present study is the first report on use of commercial ABY-6 culture in soy milk fermentation. Commercial ABY-6 culture could be used for soy milk fermentation in order to formulate probiotic soybased beverage.