Convenient Food Braised Pork Process Improvement And Comprehensive Preservation Technology Research

As the traditional specialty of china, the shredded pork with garlic sauce is used as the experimental material in this thesis. On the basis of traditional cooking methods, combining with modern food industrial processing technology and ideas, improved the shredded pork with garlic sauce production process, and materials to harden and protect color processing to ensure that the agaric and shredded bamboo shoots during storage has good taste and color. The dominant spoilage microorganisms of the shredded pork with garlic sauce were isolated and identified. The composition of the initial microflora and changes of microflora during storage under vacuum were analyzed. The antibacterial activities of nisin, tea polyphenols, natamycin, the extraction of clove and cinnamon were compared and the optimum combinations of the five natural preservatives for the preservation of chilled mutton were researched by using the response surface methodology. The effects of the optimum combination of the five natural preservatives and the microwave second sterilization and preservatives application to the shredded pork with garlic sauce were also researched. The results included several parts as follows:(1) Through orthogonal test Lg(34), it was found that the optimal hardening process is bamboo shoots and agaric material for25min in the mixed solution of0.1%sodium chloride and1.0%calcium chloride. And the optimal color protecting process is scalding the hardened material bamboo shoots silk with the mixed solution of0.3%citric acid and0.06%antiscorbutic acid for5min.(2)Thirteen strains dominant microorganisms of the shredded pork with garlic sauce were isolated and preliminary identified. Including the four strains of lactic acid bacteria,3strains of pseudomonas genera and3strains enterbacteriaceae, micrococcus, staphyloc-occus and yeast each1strain. Composition of original microflora in the shredded pork with garlic sauce:the Predominant spoilage bacteria:lactic aeid bacteria (LAB)(48.61%), Pseudomonas (32.45%), enterobacteriaceae (10.20%) and micrococcus and staphyloco-ccus(3.06%) are minor, in addition there are yeast (1.13%).(3) Effective antibacterial effects of nisin, tea polyphenols, natamycin, the extraction of clove and cinnamon were found based on single factor experiments. The optimization of the combination of the five natural preservatives was focused on the preservation of the shredded pork with garlic sauce by response surface methodology. Nisin against gram-positive bacteria was strongly inhibited, natamycin strong inhibitory effect on yeast, tea polyphenols and clove extract on the inhibitory effect of five kinds of spoilage is strong, its have a wide antibacterial spectrum, cinnamon extract on the inhibitory effect of five kinds of spoilage is not strong, it can be mixed with clove extract improved antibacterial properties.(4) The results revealed that antibacterial effects of nisin and tea polyphenols were more positive than that of natamycin, the extraction of clove and cinnamon. The results of regression analysis showed that the optimum proportion of the combination of nisin, tea polyphenols, natamycin and the extraction of clove and cinnamon was0.05%,0.02%,0.03%and3.86%respectively.Test results showed that compound natural fresh liquid itself has very strong sterilization and antibacterial properties and storage stability. The compound natural preservatives were proved effective for the preservation of the shredded pork with garlic sauce. In microbial indexes:the bacteria, lactic acid bacteria, enterobacteriaceae and the pseudomonas, staphylococcus aureus and yeasts were dropped, Physical and chemical indexes:effectively inhibit the growth of the TVB-N and pH value of meat. The effects of the optimum combination of the five natural preservatives for the preservation of the vacuum packaged shredded pork with garlic sauce were evaluated. The results revealed that the shelf life of the samples stored at (25+1)℃and (4+1)℃, were28days and35days respectively, while the contrast could preserve7days and8days.(5) Comparing the samples of sensory evaluation and microbial changes by3sterilization method we can see:Although pasteurization can be better preserved the shredded pork with garlic sauce of good quality, but its shelf-life extension of the sample than the control group only length of about9d, not suitable for shredded pork with garlic sauce sterilization methods; The samples that treated the high temperature autoclave sterilization method has the longest shelf life in the3sterilization method, however, after the sample treatment of the samples sensory quality is poor, not suitable for sterilization as a method of the shredded pork with garlic sauce; Irradiation sterilization method can effectively kill spoilage organisms, but also better preserve the good quality of the samples, suitable for the shredded pork with garlic sauce sterilization method; But one of6kGy dose of irradiation dose is too large led to the sensory scores of samples lower, not suitable for sterilization as a method of the shredded pork with garlic sauce, only the4kGy dose of irradiation in guarantee a good sensory quality of samples can also has a shelf life of about100d, is the best sterilization conditions, comparison for the industrial production of the shredded pork with garlic sauce dishes.