Effects Of Different Fermentation Modes On Qualityand Microflora Of Sour Meat

Fermented sour meat with high nutritional value,unique flavor,good probiotic properties and long shelf life is a traditional cuisine favored by ethnic minorities in China.However,this traditional fermented meat product relies on the initial presence of microorganisms in raw meat or the environment,resulting in questionable safety of sour meat products,which seriously affects the promotion of traditional cuisine with regional characteristics.At present,the addition of ferments can better achieve artificial control of the fermentation process.In addition,enzyme preparations can significantly improve food quality and have been widely added to the production of fermented meat products.Therefore,this paper explores the effects of secondary fermentation(DC),acid protease(S),Lactobacillus plantarum(L)and the combination of Lactobacillus plantarum and acid protease(LS)on microbial community structure in sour meat fermentation based on high-throughput sequencing technology,which is important for assessing the quality and microbial safety of sour meat,and the main findings show that :(1)The physical and chemical indexes of the secondary fermented sour meat were dynamically monitored.The results showed that the average p H values of the C and DC groups were 4.140.08 and 3.790.09 at the end of fermentation,and the total acid content was 4.67 and 6.52 times higher than that before fermentation.In addition,the higher amino acid nitrogen content and the number of lactic acid bacteria in the DC group were of great significance to the quality and safety of sour meat.The microbiome data showed that the community composition was more similar in the DC group of sour meat samples and was clearly distinguished from the control group.Firmicutes is the absolute dominant phylum in both two groups of sour meat.The control group had higher microbial diversity and a more complex microbial composition,including some potentially spoilage-causing bacteria,such as Psychrobacter spp.,Brochothrix spp.and Enterococcus spp.In contrast,Lactobacillus spp.was dominant in the DC group.Besides,Lactobacillus spp.,Staphylococcus spp.and Weissella spp.are the core microorganisms in both groups of sour meats.(2)Lactobacillus plantarum and acid protease were added to ferment sour meat.The experimental results showed that the acidification degree of L and LS groups was higher,and the lower p H value could effectively improve the edible safety of sour meat products and promote the growth of Lactobacillus,thus effectively shortening the fermentation period of sour meat.However,the addition of protease(S group)did not accelerate the fermentation process.The amino acid nitrogen content of S and LS groups was significantly higher than that of the control group during the fermentation process,which improved the nutritional value of sour meat to a certain extent.Microbiome data analysis showed that there were significant differences in the community structure between the S,L,LS groups and the control group.Lactobacillus was dominant in the L and LS groups,which inhibited the growth of other microorganisms.(3)The metabolic functional pathways of DC,S,L and LS groups were more abundant.Lactobacillus was positively correlated with most metabolic pathways such as biosynthesis and energy metabolism of other secondary metabolites,while Weissella and Psychrobacter were negatively correlated with amino acid metabolism,lipid metabolism and biosynthesis of other secondary metabolites.In summary,the secondary fermentation group and Lactobacillus starter and enzyme combination group can significantly shorten the fermentation period of sour meat,inhibit the growth of potential spoilage pathogens,and improve the quality and safety of traditional fermented sour meat products.