Study On Fermentation Process Optimization And Quality Characteristics Of Fermented Beef Jerky

Beef jerky is nutritious,delicious and convenient,but there are many defects in beef jerky produced by traditional technology,such as hard texture and unstable quality.The fermented meat product industry in China started late.The development of fermented beef jerky is mainly still in the stage of laboratory research and there are few products on the market.In this study,the beef rump was used as raw material to develop a kind of fermented beef jerky with rich nutrition,unique flavor,safety and health through screening starter,optimizing fermentation process and seasoning formula.The fermentation characteristics,quality and flavor compounds of fermented beef jerky were studied and investigated.This provides a theoretical basis for the development and industrial production of new products of fermented beef jerky.The main research contents and results of this paper are as follows:1.The research on the basic fermentation characteristics of strains showed that Pediococcus acidilactici（P.acidilactici）,Lactobacillus sakei（L.sakei）and Staphylococcus xylosus（S.xylosus）could be used to prepare fermented beef jerky.Through comparative analysis of the effects of different strain combinations on the physical and chemical properties and sensory quality of fermented beef jerky,S.xylosus and L.sakei were determined as the starter for preparing fermented beef jerky in this study from the perspectives of fast acid production,flavour formation and histamine reduction.2.The research on the fermentation characteristics of fermented beef jerky showed that with the extension of fermentation time,the pH value,Aw value,and nitrite residue of fermented beef significantly decreased.The total free amino acids content significantly increased and the histamine content and TBARS value slowly increasd.The macromolecular protein was degraded,and beef texture and color were improved.When the S.xylosus:L.sakei was 1:3,2:1,3:1,the inoculation amount was10⁶-10⁷CFU/g,the fermentation time was 16-32 h and the fermentation temperature was 32-42℃,the quality of fermented beef was better.3.Based on the sensory evaluation of fuzzy mathematics and the response surface method to optimize the fermentation process of fermented beef jerky and the study of microbial prediction model showed that the multiple quadratic regression equations of the relationships between the pH value（Y₁）,comprehensive score（Y₂）of fermented beef jerky,the number of lactic acid bacteria（Y₃）,the number of staphylococci（Y₄）,the total number of colonies（Y₅）and the ratio of strains（X₁）,inoculation amount（X₂）,fermentation temperature（X₃）,and fermentation time（X₄）were as follows:Y₁=4.4-0.029X₁-0.034X₂-0.16X₃-0.025X₄-0.018X₁X₂+0.026X₁X₃+0.066X₁X₄+0.00325X₂X₃-0.05X₂X₄-0.018X₃X₄+0.023X₁²-0.038X₂²+0.19X₃²-0.086X₄²Y₂=77.17+0.3X₁+0.72X₂-0.14X₃+0.31X₄-0.61X₁X₂-1.44X₁X₃-0.52X₁X₄-0.83X₂X₃-1.94X₂X₄+0.34X₃X₄+0.33X₁²+1.09X₂²-0.23X₃²+1.15X₄²Y₃=12.19-0.00173X₁+0.061X₂-0.012X₃-0.092X₄+0.018X₁X₂+0.083X₁X₃+0.073X₁X₄+0.16X₂X₃+0.039X₂X₄-0.2X₃X₄-0.37X₁²-0.052X₂²-1.22X₃²+0.079X₄²Y₄=10.1-0.091X₁+0.047X₂+0.1X₃-0.092X₄-0.0098X₁X₂-0.22X₁X₃-0.1X₁X₄-0.014X₂X₃-0.13X₂X₄+0.054X₃X₄-0.22X₁²-0.16X₂²-0.98X₃²-0.2X₄²Y₅=12.14-0.034X₁+0.09X₂-0.024X₃-0.12X₄+0.021X₁X₂+0.23X₁X₃+0.087X₁X₄+0.032X₂X₃+0.039X₂X₄-0.16X₃X₄-0.32X₁²-0.055X₂²-1.22X₃²+0.072X₄²The optimal fermentation parameters of fermented beef jerky were:S.xylosus:L.sakei=1:3,the inoculation amount was 10⁷CFU/g,the fermentation time was 16 h,and the fermentation temperature was 32℃.Under these conditions,the comprehensive sensory score of fermented beef jerky was 85.21.4.The research on the optimization of fermented beef jerky seasoning formula showed that the quality of fermented beef jerky was better when salt was 1-2%,glucose was 0.5-1.5%,sodium nitrite was 0.009-0.012%,sugar was 2-3%,soy sauce was 1-5%,cooking wine was 1-3%,chili powder was 0.5-1.5%,thirteen spices was0.5-1.5%.The orthogonal optimal combination of seasoning formula was 1%salt,0.5%glucose,and 3%soy sauce.Under these conditions,the comprehensive sensory score of fermented beef jerky was 85.63.5.The research on the physical and chemical properties and flavor quality in the processing of fermented beef jerky showed that compared with before fermentation,the pH value,water activity,nitrite residue,hardness and chewiness of fermented beef decreased significantly.Lactobacillus and Staphylococcus became the dominant strains,and the growth of Enterobacter was inhibited to some extent.The redness value and free amino acid content increased significantly,and the proportion of umami amino acids was the highest.The main free fatty acids of fermented beef were palmitic acid,stearic acid,oleic acid and linoleic acid,of which oleic acid accounted for the largest proportion.47 kinds of volatile compounds were detected after beef fermentation,higher than 42 kinds before beef fermentation.The types and relative content of aldehydes,alcohols,phenols,esters,acids,nitrogen and other compounds in beef jerky were increased.