Study On The Effect Of Fermentation Process On The Edible Quality Of Pork Jerky

Jerky is the well-known traditional meat products in our country, they not only have the characteristics of high protein, low fat, delicious, loved by people, but also have small size easy to carry. Under the condition of the traditional process, meat production after a long time of drying process and a short time of baking process, make the product too hard, and also effects the elasticity and chewiness of products; In addition in the traditional process, the flavor formation of product mainly by Millard reaction, lead to a single flavor, this constrains the development of jerky. For jerky tastes too hard to chew at present, there were many scholars try to solve this problem mainly by adding moisturize or render agent, etc. Many studies have suggest that the fermentation can improve the quality of sausage and other meat products quality, such as texture and flavor. This paper chooses three kinds of meat starter cultures, on the basis of the fermentation characteristics, choose the starter culture combination which suitable for fermentation pork, combined with modern biological fermentation technology, to find out the optimal fermentation technology to make a kind of jerk which is easier to chew and has the special flavor of fermentation. This study is dedicated to understanding the changes of microbial phase and characteristics of selected starter cultures as well as chemical and microbial properties, the origin of volatile flavor and the storage of pork jerky. Promote the development of meat products processing industry in China has important application value.Using Lactobacillus plantarum(L.plantarum) and Pedicoccus pentosaceus(P.pentosaceus) and Staphylococcus carnosus(S.carnosus) as starter cultures, investigate the growth characteristic and fermentation characteristics of various strains. The growth characteristics and produce acid properties of three strains were performed. Results showed that L.plantarum and P.pentosaceus have shorter growth demurrage, after 4 h into the logarithmic phase, S.carnosus in 2 h into the logarithmic phase. The growth of the three kinds of bacteria demurrage are short. L.plantarum and P.pentosaceus has the ability to produce acid; S.carnosus and P.pentosaceus produce protease and lipase, L.plantarum has protease activity. There is no significant antagonism between the three kinds of bacteria, can be used as mixed starter cultures.Pig meat as raw materials, using different combinations of starter cultures to make pork jerky and to compare the texture, flavor and physical and chemical characteristics. The results showed that: the products inoculated L.plantarum and P.pentosaceus and S.carnosus which shearing force and chewiness were significantly lower than traditional pork jerky(p<0.05); fermented changes the microstructure of products, the content of volatile flavor compounds in the test group were significantly higher, given the jerky unique flavor; the experimental groups lower pH(5.15) inhibit other bacteria to growth and reproduction, to ensure the safety of the product.Three kinds of bacteria complex(1:1:1) as the mixed starter cultures to produced jerky, pork protein and lipid oxidation were studied during fermentation processing. The results showed that: during the fermentation processing non-protein nitrogen(NPN) and amino nitrogen(AAN) and free amino acids(FAA) content were increased, the majority of free amino acids gradually increased during fermented, in which essential amino acids content changed from 205.13 mg/100 g to 85.24 mg/100g; protein degradation index(PI) and myofibrillar fragmentation index(MFI) increased respectively, changed from 7.38% and 41.95 to 17.44% and 82.98, sarcoplasmic proteins and myofibrillar protein content decreased, respectively, decreased from27.61 g/100 g dry basis and 14.79 g/100 g dry basis to 18.74 g/100 g dry basis and 10.14 g/100 g dry basis. Fat peroxide value(POV), thiobarbituric acid value(TBA), carbonyl compounds and denies values showed a gradual upward trend in the fermentation process, indicated that the degradation and oxidation of fat.Make different combinations of strains, strain ratio, fermentation temperature, fermentation time, starter culture inoculation quantity as the single factor of single factor experiment, pH and sensory score as the testing index, find out the optimal levels of each factor and the main influence factors. The results show that the jerky of three bacteria mixed group product has suitable pH and the highest sensory score, so make it as the microbial starter cultures of fermented pork jerky. The best fermentation process optimization by response surface method on the basis of single factor experiment were to studied, fermented temperature, fermented time and starter cultures inoculation as the main factors that effecting the quality of fermentation pork jerky to do response surface experiments, in order to determine the optimal fermentation process, the response value is shearing force and sensory score. Best fermented condition is: the glucose content is 2%, the fermented temperature is 21℃, the fermented time is 42 h, the starter cultures inoculation is 3.2×107 cfu/g. Under this condition, fermented pork jerky has low shear force(5233 g), and high sensory score(8.5).