Research On Fermentaition Process Optimization And Drying Characteristics Of Fermented Dried Venison

This article is a part of the research: Changchun city development of modernagriculture science and technology support project-the key technology of fruits andvegetables compound fermentation deer meat in process (12XN15).In recent years, the deer breeding industry in Jilin province has developed rapidly,the number of deer has reached200,000to300,000, and the slaughter capacity is from30,000to40,000every year. The source of deer is increasingly rich, while itsprocessing products are little. As people living standard rise, new meat productswhich have balanced nutrition, long storage life and unique flavor is urgentlyneeded.The article isolated and purified lactic acid bacteria (LAB) from naturallyfermented sauerkraut juice, and conducted a preliminary identification. Thefermentation characteristics of the strain and Debaryomyces hansenii were analyzed,and the both bacterias with a certain ratio as a mixed starter culture were added tovenison to further research the physical-chemical characteristics of fermentationprocess and drying characteristics of fermented dried venison.1.By studying the properties (the optimum growth temperature, the curve growthand acid production, the resistance of salt and nitrite, the antagonism between the twostrains) of LAB and Debaryomyces hansenii, we have obtained the followingconclusions:(1)Isolated strains was identified as LAB by Gram stain test, indole test,hydrogen sulfide production test, gelatin liquefaction test, catalase test and nitratereduction test.(2)The optimum growth temperature of the LAB is about35℃, itsgrowth stable period appears15h after cultured, and it can withstand the concentrationof salt is2%and nitrite is0.009%, so it is suitable to serve as the starter culture offermented meat products.(3)The optimum growth temperature of Debaryomyceshansenii is about30℃, its stationary growth phase appears18h after cultured, and itcan tolerate2%salt and0.006%nitrite.(4)There is no antagonism between the LABand Debaryomyces hansenii.2.Through studying the optimization processing parameters of venisonfermentation, the conclusions are as follows:(1)Fermentation time, temperature andinoculation amount are important factors influencing venison fermentationcharacteristics. By Box-Behnken designing, the pH and sensory scores of fermentedvenison were indicators, they are used to optimiz fermentation time (A), fermentation temperature (B) and inoculum (C). The quadratic response surface regression models are obtained: pH=4.72-0.021A-0.019B-0.10C-3.333E-0.003AB+0.082AC+0.043BC+0.027A2+0.072B2+0.050C2SensoryScores=87.75+0.89A-4.91B-1.79C+0.83AB-2.03AC+1.52BC-1.38A2-3.91B2-4.21C2(2)The optimum fermentation conditions for venison are determined:fermentation time is20.86h, fermentation temperature is27.51℃and inoculum is2.16%. The average pH and sensory score of fermentated dried venison were measured; they are5.07and89.21, respectively.3.By studying the influences of natural fermentation and inoculated fermentation on the physicochemical properties(moisture content, total free amino acids content, protein molecular weight, texture characteristics, volatile basic nitrogen, microbial indicators and thiobarbituric acid) of venison and concluted that:(1)In the whole fermentation process, the moisture contents decreased significantly both in natural fermentated venisonand in inoculated fermentated venison, the free fatty acids content in inoculated fermentation was significantly higher, however, both volatile basic nitrogen and thiobarbituric acid were lower.(2)The degradation degree of protein molecules in inoculated fermentation ones was higher.(3)In both natural fermentation ones and inoculated ones, hardness, gumminess and chewiness significantly increased, while there was no significant difference in elasticity.(4)Compared with control ones, counts of lactic acid bacteria and yeast were significantly higher than that in inoculated ones, but counts of E. coli were lower.4.The research on hot-microwave drying fermented venison and drying kinetics model showed that:(1) when the hot air drying temperature was65℃, drying time was3h, fermented dried venison obtained had the highest sensory score. At the same time, when the microwave power was350W, drying time was120s, fermented dried venison obtained had the highest sensory score, too.(2) Hot air drying kinetics model:MR=0.6483exp(-0.01226t419685)+0.00352t(3) The optimum process parameters of hot air-microwave drying fermentated venison: hot air temperature65℃, drying time2h, microwave power350W, drying time20s.(4) Microwave drying kinetics model:MR=-2631.53577-43.1221lt+0.17667t2 Innovation:This is the first time to use lactic acid bacteria isolated from natural fermentedsauerkraut juice and Debaryomyces hansenii as a mixed starter culture for venisonfermentation, develop high-quality fermented dried venison, and systematic study itsdrying kinetics, it open a new way for deep processing of venison.