Study On The Process Condition And Quality Impact Of Rapid Fermentation Low-salt Sour Meat By Lactic Acid Bacteria

As a traditional fermented product,fermented sour meat is unique and delicious.However,the traditional sour meat is limited by the production conditions,cause meat products to be eaten many times in one fermentation.The production process depends on experience under natural conditions,it is inevitable there are harmful microorganisms,food safety can not be guaranteed;The shelf life of products is mainly cured by high-concentration salt,which is not suitable for long-term consumption.The long fermentation cycle and unstable product quality restrict the large-scale and industrialized production of this product.In this paper,based on the microbiological and biochemical characteristics of traditional sour meat,use the anti-oxidation lactic acid bacteria preparation fermented sour meat,developed a high-quality fermentation meat that can not only maintain the flavor characteristics of traditional sour meat,but also could achieve industrial production.This study explored the production process of sour meat,established a rapid fermentation cycle under controlled conditions,studied the nutrition and safety of sour meat,and used it to guide production so that ethnic foods could be further developed and improve economic efficiency.It will pave the way for industrial upgrading of traditional sour meat products.In this study,two lactic acid bacteria(LAB)strains namely Lactobacillus curvatus SR6 and Pediococcus pentosaceus SR4-2 that screened from the Dong minority fermented meat were used as mixed starter culture to fermented low-salt sour meat.Through the optimization of process conditions,the optimum technological conditions for fermenting sour meat are determined.On this basis,the double-bacterial fermented sour meat was used as the experimental group,and the traditional natural fermented sour meat served as the control group.The change of microbial,chemicalindicators of this two group sour meat and the antioxidant activity of sour meat peptide during the fermentation were conducted comparative analysis,aimed to provide a theoretical basis for actual production.The main results and conclusions are as follows:The process conditions of fermented sour meat were optimized by single factor and orthogonal experiments L9(34),the sensory evaluation score and p H value were used as evaluation indexes,the results showed that the optimum process conditions were 8% of salt,2% of inoculating amount,45% of glutinous rice and 15℃ of temperature.Microorganisms and physicochemical indexes of sour meat produced by the optimum process conditions were dynamically monitored during the fermentation process,assessed the effect of inoculation with two bacteria on the quality of sour meat synthetically.The results showed:(1)During the early stage of fermentation,the lactic acid bacteria of experimental group proliferated greatly and became the dominant bacteria at 30 days.After 30 days of fermentation,no coliform group was detected in the experimental group,sour meat inoculated with the starter significantly inhibited the growth and reproduction of coliform.(2)In the experimental group,the p H value and the water activity decreased rapidly.At the 30 th day of fermentation,there was a significant difference with control group(P < 0.05),and reached Aw value of of the control group at 90 th day.During the whole fermentation process,the salt content of two groups sour meat is controlled below 5%,contented the health requirements.(3)The L* value and a* value of the experimental meat group were significantly higher than that of the control group at the 30 th day of fermentation and b* value was significantly lower than that of the control group(P<0.05).(4)Compared with the control group,the total free amino acid(TFAA)in the experimental group increased significantly,and the total free amino acid at the time of fermentation increased the nutritional quality of the product at 30 d.(5)GC/MS technology was used to analyze the flavour substances in the experimental group and the control group.102 and 89 volatile flavors were identified,including esters,alcohols,aldehydes,ketones,acids,and olefins.Furan compounds,the flavor of the experimental group was morethan the control group in the type and content.Based on the dynamic monitoring of the contents of volatile base nitrogen,nitrite,malondialdehyde,and biogenic amines,the effects of two strains of lactic acid bacteria on the safety of sour meat fermentation were studied.The results showed:(1)The TVBN value and malondialdehyde(MDA)value of sour meat showed an increasing tendency during the fermentation process,but the experimental group increased slowly and the content was significantly lower than the control group(P<0.05);the nitrite content At the later stage of fermentation,it showed a downward trend.At 180 days of fermentation,the nitrite content of the experimental group was significantly lower than that of the control group.(2)Seven biogenic amines were detected in the experimental and control groups: tryptamine,2-phenylethylamine,putrescine,cadaverine,histamine,spermidine,and spermine.Tyramine was not detected throughout the fermentation.The total amount of 7 biogenic amines in the experimental group was significantly lower than that in the control group,indicating that the inoculation of lactic acid bacteria can significantly inhibit the increase of biogenic amine content in acid meat.It was investigated that the scavenging abilities of sour meat peptide to reactive oxygen(ROS)in vitro,as well as protect effect on damaged DNA.The results showed that when the concentration was 50mg/m L,the inhibitory rate of superoxide anion in experimental group was 68.89%±0.09,and the inhibition rate to DNA damage was 89.89%±0.08;when the concentration was 1mg/m L,the inhibition rate of hydroxyl radical in experimental group was 85.61%±0.11.At the concentration of5.0 mg/m L,the DPPH radical scavenging rate of the acid peptide was 54.74%±0.09,which was higher than the control group of 43.79%±0.07,increased about 20%.The experimental results showed that the antioxidant activity of the acid peptides in the experimental group and the activity of DNA damage protection were significantly stronger than those in the control group(P<0.05),but different results exist in different systems.In summary,the sour meat fermented by Lactobacillus bentiformis SR6 and Pediococcus pentosaceus SR4-2 has bright color and good flavor,and has the effectsof scavenging free radicals and protecting DNA damage in vitro.The inoculation fermentation shortens the fermentation time to 30 days.Achieve and superior to the quality of traditional fermented sour meat,and improve the nutrition and safety of the product.