Study On Frozen Grass Carp Frittered Meat Sausages Fermented By Mixed Starter Cultures

This paper had primary studied the biochemical change and flavor change of frozen grass carp frittered meat sausages during fermentation. Frozen grass carp frittered meat was been used as raw materials and the mixed starter cultures had been optimized. The frozen grass carp meat sausage was produced under the optimal technological condition which had been optimized by response surface method. The protein components change and microstructure change of frozen grass carp frittered meat sausages during the gel forming process had been also studied in this paper. The main results were summarized as follow:(1)Screening of mixed starter cultures for grass carp fish fillet fermentation.The fermentation performance of Bacillus natto(n-3), Bifidobacierium bifidum(sq-1), Lactobacillus acidophilus(ss-1-1), Pediococcus pentosaceus(x-1, x-2,x-3, x-4, x-5), Lactobacillus plantarum(P-1.1856), Lactobacillus harbinensis(L.h)had been studied and determined the bacterial growth curve, the acid production rate,salt tolerance ability, strain growth under different temperature conditions, the protease secrete capacity, amino acid decarboxylase ability, antagonistic and the utilization characteristics for fish paste. The results showed that the mixed starter cultures that suitable for grass carp fish fillet fermentation is n-3、x-4 and x-5.(2)Optimization of fermentation conditions of frozen grass carp frittered meat sausages with mixed starter cultures by response surface methodology.To optimize the technological parameters for frozen grass carp frittered meat sausages using a strain of Bacillus Natto(n-3) and two strains of Pediococcus Pentosaceus(x-4, x-5) as mixed starter cultures as leaven by response surface method. Based on the single factor experiment, the inoculation amount of mixed starter culture, the glucose amount and the ratio of mixed start culture had been determined in this paper, and the NaCl amount, the fermentation temperature and the fermentation time were chosen as influencing factors, and the pH was selected as response value and the mathematical modal was established by Box-Behken central composite design. The optimal fermentation conditions were determined as follows: the inoculation amount of mixed starter culture was 3%, the glucose amount was 2%, the ratio of mixed start culture was 1:1:1, the NaCl amount was 2%, the fermentative temperature was 38.7℃ and the fermentative time was 36 h, the PH of the frozen grass carp frittered meat sausages was 5.19 in this optimized conditions.(3)Effect of mixed starter cultures on the flavor during the fermentation of frozen grass carp frittered meat sausages.The effects of mixed starter cultures on the frozen grass carp frittered meat sausages were investigated by assaying texture properties,gel characteristic, protein electrophoresis, fourier infrared spectrum, differential scanning calorimetry and scanning electron microscope(SEM). As fermentation time goes by, the results showed as follow. The pH and moisture content of the sample reduced gradually. The total protein content had an increase. The water soluble protein and salt soluble protein degradation was obvious degraded and the content was reduced continuously. The sample had obvious increased in hardness, gumminess,chewiness and gel properties. The tertiary structure of salt-soluble meat protein had been destroyed in a certain degree, although its protein denaturation temperature had an increase, the salt-soluble meat protein could intact retain triple-helical domain. The scanning electron microscope(SEM) confired the sample had smaller pores than before, that is, the sample became more compact while fermented with mixed starter cultures.(4)The safety study of the frozen grass carp frittered meat sausages fermented by mixed starter cultures.The taste change of frozen grass carp frittered meat sausages influenced by mixed starter cultures during the fermentation process were studied in this paper. The research method was electronic nose combined with amino acid analysis. The raw material was frozen grass carp frittered meat and the results were showed as follows. The first and second min axes generally represent the main characteristic information of frozen grass carp frittered meat sausages during fermentation, whose sum of variances was 99.985% by PCA method. The sum of variances of the first and second main axes was 93.969% by DFA method which had good concentration and single tendency. The electronic nose responded differently to the frozen grass carp frittered meat sausages during fermentation, and the six sensors of the nose could distinguish the flavors of frozen grass carp frittered meat sausages during fermentation. Sensors T70/2, PA/2, P30/1 and P40/2 had a relatively higher resistivity than others. The free amino acid analysis showed that the amino acids Glu,His, Ala, Val, Phe and Lys which TAV were more than 1 may contribute to the crad taste of sweetness, bitterness, delicate flavour and tartness.(5)Effects of mixed start cultures on the functional properties of frozen grass carp frittered meat sausages.The effects of one group mixed starter cultures, combined with Bacillus natto and Lactobacillus pentosus, and a batch without starter as controlon biogenic amines accumulation in the frozen grass carp frittered meat sausages during fermentation were investigated. Methods of simultaneous determination of six biogenic amines(tryptamine, putrescine, cadaverine, histamine, tyramine, spermine)by high-performance liquid chromatography were developed. The method had a good resolution in 30 mines and good linearity(R2>0.999), the recovery rate was between97.35%~103.00%, and the RSD of precision, repeatability were all lower than 10%.Fermentation inoculated with mixed starter cultures could inhibited the growth of contaminant microoroganisms, such as Staphylococcus aureus, Enterobacteriaceae and Pseudomonas, and suppressed the accumlation of putrescine, cadaverine,histamine, tyramine. In order to improve hygienic quality of frozen grass carp frittered meat sausages, Bacillus natto, Lactobacillus pentosus were added to activate the function of negative-decarboxylase which can prevent biogenic amine formation,inhibited the spoilage bacteria and pathogens.