Exopolysaccharide producing starter cultures positively influence on microbiological, physicochemical, and sensory properties of probiotic goats' milk set‐yoghurt

Abstract

In the current study, the effect of two exopolysaccharide (EPS) producing starter cultures (YF-L903 and YC-X11) and a commercial starter culture (STI-12) on the physicochemical, microbiological, and sensory attributes of probiotic goats' milk set-yoghurt was evaluated after processing and storage at 4°C for 28 days. The type of starter culture had no effect (p > .05) on acidification of set-yoghurts. There were no differences (p > .05) in terms of viable cell counts in two tested set-yoghurts; more or less similar final cell counts were observed for Bifidobacterium animalis subsp. lactis BB-12 (~7.9 log cfu/g), Streptococcus thermophilus (~8.2 log cfu/g), and Lactobacillus delbrueckii subsp. bulgaricus (~7.8 log cfu/g). In situ EPS production of the starter cultures resulted goats' milk set-yoghurt with low syneresis, high apparent viscosity, and improved sensory attributes. Practical applications This study showed that in situ EPS production by EPS producing starter cultures markedly improved the quality attributes of goats' milk set-yoghurt. EPS production of starter cultures significantly reduced syneresis and improved apparent viscosity and sensory attributes of goats' milk set-yoghurt. This work can have an impact in advancing our understanding of the role of EPS producing starter within the context of goats' milk set-yoghurt production and in developing improved fermented goats' milk based dairy products. There is very little microbiological and physicochemical information on goats' milk set-yoghurt produced with EPS producing strains, and little understanding on the role of the produced EPS. To the best of our knowledge this is the first study investigating the microbiological and physicochemical characteristics of goats' milk set yoghurts produced with the help of EPS producing starter cultures. Therefore, we believe that this work can have an impact in advancing our understanding of the role of EPS producing starter within the context of goats' milk yoghurt production and in developing improved fermented goats' milk based dairy products.