The Investigation And Inhibition Study Of Spoilage Microorganismsin Salted Turnip

Pickled turnip is becoming a favorite daily standing side dish for the fresh, fragrant, crisp, refreshing properties. Bulging bag easily occurs in salt, sweeteners, vacuum bagged pickled turnip by the production, storage, transportation, sales process, resulting in substantial waste of raw materials and significant economic losses. Pickled turnip cause corruption is usually caused by a variety of spoilage organisms. It is a convenient and effective method to combine complex process control with scientific use of preservatives.Research on the producing process of pickled turnip : salt concentration, desalination, sterilization temperature, sterilization time. The results of the study show that: 16% of salt concentration is appropriate, too high or too low will affect the quality of the product. The optimal desalination process as the soaking time is 20 min, the ratio of solid to liquid was 1:4, the influence of soaking time is more important than ratio of material, ratio of material to water after 1:4 salt content did not change significantly. The best sterilization temperature and time of slice or filamentous pickled turnip is 80℃, 15min; The best sterilization temperature and time of strip pickled turnip is 85℃, 20 min.Sensory test, pH value, salt content, total acid content of pickled turnip is being tested using pH meter and titration method. The pH value of the spoilage pickled turnip without bulge is 3.18~3.44, salt content is(7.03g~7.31g)/100 g, total acid content is( 1.98g~2.32g)/100g; The pH value of the spoilage pickled turnip with bulge is 3.04~3.37, salt content is(6.94g~7.26g)/100 g, total acid content is( 1.87g~2.11g)/100g; The pH value of the pickled turnip control is4.54~4.83, salt content is(7.51g~7.74g)/100 g, total acid content is(0.38g~0.42g)/100 g.Seven bacteria strains were screened out following the microbial plat culture and separation ways from the first of spoilage pickled turnip. Three bacteria strains and two yeasts were screened out following the microbial plat culture and separation ways from the second of spoilage pickled turnip. By morphological identification, Gram staining and acid gas experiment, seven strains of bacteria are gram-positive bacteria, strain X1~X6 for rod, strain X7 for spherical; strain X1~X3 produce acid but not gas, strain X4~X7 does not produce acid and gas, strain Y1, Y2 produce gas but not acid.According to biochemical tests, as well as 16 S rRNA and 26 S rRNA of D1 / D2 sequencing analysis,X1 is identified as Bacillus sp.,X2 is identified as Bacillus subtilis,X3 is identified as Bacillus megaterium,X4 is identified as Bacillus boroniphilus,X5 is identified as Lysinibacillus sphaericus, X6 is identified as Bacillus gibsonii, X7 is identified as Uncultured bacterium,Y1 is identified as Candida pararugosa,Y2 is identified as Candida zemplinina.Use the separation of pure culture of spoilage microorganism, determination of preservative inhibition effect on it. Single factor experiment results show that sodium benzoate, sodium dehydroacetic acid has obvious inhibitory action to the spoilage microorganisms. The orthogonal experiment optimization to get the best compound preservative formula is: sodium benzoate 0.4 g/L, sodium dehydroacetic acid sodium 0.2 g/L. This compound preservative exhibited an excellent suppression effect on Lysinibacillus sphaericus, Bacillus sp. The antibacterial rate of the two strains could reach to 99.77%、99.86% respectively. With reference to the use of food preservatives in pickled vegetables technical standards and regulations, effective and safe compound preservatives are found out and can be used in actual production, so as to provide theoretical basis for the practical production of pickled turnip.