Effect of autochthonous starter cultures on microbiological and physico-chemical characteristics of Suan yu, a traditional Chinese low salt fermented fish

In this study, three groups of mixed starter cultures (S1: Lactobacillus plantarum 120, Staphylococcus xylosus 135 and Saccharomyces cerevisiae 31; S2: L. plantarum 145, S. xylosus 135 and S. cerevisiae 22; S3: Pediococcus pentosaceus 220; S. xylosus 135 and S. cerevisiae 22), isolated from Suan yu, were inoculated to produce the traditional fermented fish. After 42 days fermentation at 24 °C, Suan yu inoculated with different mixed starter cultures underwent rapid growth of lactic acid bacteria (LAB), declined pH, suppressed increase of thiobarbituric acid (TBARS) and total volatile base nitrogen (TVB-N) as well as growth of spoilage bacteria and pathogens. Besides, Suan yu had higher contents of non-protein nitrogen (NPN) and total free amino acids (FAA) compared to the control (P < 0.05). The muscle proteins were severely hydrolyzed during fermentation (SDS-PAGE). Moreover, the sensory evaluation indicates the fermented fish was more widely accepted than the control. The results suggest that the inoculation with S1, S2 and S3 reduced the lag time that fermentation began and improved the quality of Suan yu.