| Pixian broad bean paste is a traditional fermented condiment in China.The main raw materials include Erjing pepper,broad bean,wheat flour and salt,etc.It is naturally fermented by traditional techniques.Its unique brewing process is known as "the soul of Sichuan cuisine".Because the fermentation method of Pixian broad bean paste is open natural fermentation,the microbial population structure is complex and diverse during the fermentation process,and the finished product is not sterilized.Some aerogenic microorganisms will use the remaining nutrients for secondary fermentation,and then grow and reproduce in large quantities The gas is generated,which causes the bag to swell and the product to become rancid and discolored.The gas production is more serious in summer and when the temperature is higher.The Pixian broad bean paste sauce in the bulging jar usually has the characteristics of high acidity and odor,which not only affects the quality and safety of the product,but also causes waste of raw materials and economic losses to the enterprise.This thesis takes Pixian broad bean paste Sauce as the research object,investigates and compares the sensory and physical and chemical indicators of the samples of the Pixian broad bean paste Sauce and the normal cans;the aerogenic microorganisms in the Pixian broad bean paste Sauce samples of the can And analyzed the biological characteristics of aerogenic microorganisms;explored the inhibitory effects of three common preservatives on aerogenic microorganisms,and optimized and validated the formula of compound preservatives.The main findings are as follows:1.The sensory index and physical and chemical index of the expansion tank and normal Pixian bean paste samples were compared.Compared with normal Pixian broad bean paste,the bulging Pixian broad bean paste sauce is dark brown and dull,with an irritating odor,aftertaste without fat fragrance and slightly sour taste;its moisture content has decreased by 4.00g/100 g,total acid content and The content of amino acid nitrogen increased by 0.35g/100 g and 0.03g/100 g,respectively,while the edible salt,acid value and peroxide value index did not change significantly.2.Isolate,purify and screen the aerogenic microorganisms in the sample of Pixian broad bean pastejiang in the expansion tank,and obtain two strains with aerogenic ability.The two microorganisms were identified by traditional identification methods and 16 s DNA molecular biology methods.For Bacillus amyloliquefaciens and Bacillus subtilis.3.The biological characteristics of the two aerogenic microorganisms were studied,and it was found that the two strains were facultative anaerobic bacteria and had the ability to grow in both aerobic and anaerobic environments.The two strains can still grow in an environment with a salinity of 20%,a temperature of 60 ° C,and a pH of 4.0.The two product microorganisms have good characteristics of high salt resistance,high temperature resistance,and acid resistance.4.To explore the inhibitory effect of common condiment preservatives on two aerogenic microorganisms,and to determine nisin,sodium diacetate and potassium sorbate as preservatives for the expansion of Pixian bean paste.In a medium with a salinity of 18%,the minimum inhibitory concentration values(MIC)of Nisin,sodium diacetate and potassium sorbate against the two strains were 0.03g/ kg,0.40g/kg and 0.80g/kg,respectively.Through orthogonal experiments to optimize the formulation of the composite preservatives,the concentration of the three preservatives was 0.04g/kg,0.30g/kg,0.40g/kg,and inhibition verification experiments were carried out.No gas production occurred within 3 months at 37 ℃.Modification of the compound preservative formulation can effectively suppress the gas production of Pixian bean paste.. |
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