Screening and Identification of Lactic Acid Bacteria from Traditional Vinasse Fish and Optimization of Parameters for Preparing Fermented Chinese herring

Abstract

A novel inoculated fermentation method combined with traditional vinasse pickling was studied,with the purpose to realize industrial and standardized production of vinasse fish with modern biotechnology.The MRS selective medium was used to isolate the dominant microorganisms from traditional vinasse fish.The isolated strains were then identified by physiological and biochemical analysis combined with MIDI identification system.The isolated strains were cultivated and inoculated the Chinese herring for complex fermentation.Changes of the protein content,total acidity,volatile basic nitrogen(TVBN),amino nitrogen,pH of the fish during fermentation were analyzed,the factors effected the fermentation were investigated by single factor test and the optimal fermentation parameters were then established by response surface methodology(RSM).The results showed that one of the dominant strains in traditional vinnase fish was identified as Lactobacillus fermentum;either too low or too high fermentation temperature was not benefit to the formation of good flavor.Increased inoculation dosage could shorten the fermentation period,while ratio of vinasse could obviously affect the taste of the product.The optimum parameters were established by RSM as fermenting at 20℃,with a ratio of vinnase of 2.5,and a inoculation dosage of 2.28%.The fermentation period was reduced from more than 30 days to less than 12 days.Compared to sole inoculated fermentation,a longer maturation period was needed for the complex fermentation,however the resulted product prepared under the above conditions had a better quality and a typical flavor of traditional vinnase fish.