Abstract

This study investigates the effects of controlled fermentation using a specific starter culture on some properties of soy-yoghurt, focusing on the physicochemical and microbiological properties after production and storage. The results showed that the starter culture improved both the physicochemical properties and shelf life of soy-yoghurt. Specifically, pH dropped in controlled fermented soy-yoghurt (CFSY) from 6.18 to 5.40 after 8 hours of fermentation, whereas spontaneously fermented soy-yoghurt (SFSY) had a slight pH decrease from 6.51 to 6.04. Fermentation influenced significant increase in Total Titratable Acidity (TTA) for CFSY from 0.38 to 2.08 g/L, while the TTA of SFSY only slightly increased from 0.04 to 0.10 g/L. Proximate analysis revealed that SFSY has higher moisture content (87.09%), crude fat (3.16%), crude fibre (0.05%) and carbohydrate (5.46%) compared to CFSY. Sensory evaluations showed that while SFSY scored higher in colour, while CFSY scored higher in flavour, texture and appearance. During storage, the pH of CFSY declined with respect to storage days, while the TTA increased. In conclusion, controlled fermentation improved the physicochemical, nutritional and sensory properties in soy-yoghurt by enhancing the storage stability of the product.