| Fermented soybean products is the main raw material for production of soybeans, the maximalpotential safety hazard may be aflatoxin from the process of harvest and storage,which are effected by external environment. These types of products mainly according to workshop-based model. fermentation is carried out in an open environment, and participate in a wide range of microbial fermentation, susceptible to bacterial contamination caused by aflatoxin. Therefore, fermented soy products both in the processing of raw materials or in the starter, fermentation have security risks. This paper use of probiotics can not only inhibit the absorption of aflatoxin production and removal of existing aflatoxin, is also the guarantee of the butter aroma characteristics of song. In view of the above problems, using probiotics (Lactobacillus) and Aspergillus oryzae fermentation watercress mixture, this way, to control aflatoxin production process, but also ensures that the original flavor of watercress unchanged, is a safe, reliable biological control methods.In the course of the study subjects. First of all: the amino nitrogen as an index. By Single factor and orthogonal test, the best starter Aspergillus oryzae 3.042 conditions: Koji temperature 34℃, starter for 3 days, the seminiferous volume / volume watercress 1:5000. Starter under the best conditions,fermentation at 50℃shorten the fermentation time. In the days 3,6,9,12 of fermentation measured levels of aflatoxin B1 were 3.024μg/kg,3.026μg/kg,3.033μg/kg,3.037μg/kg, Does not exceed the national standard for aflatoxin B1 content of the limit, But is was a slow rise, so there is a hidden danger by bacterial contamination, By viable count test, The Aspergillus spore suspension were inoculated to Lactobacillus MRS24-hour culture medium, pH6.8MRS culture medium, pH5.6MRS culture medium inoculums were inoculated to a different PDA plate viable counts. Three groups of experimental data obtained were:46×104 cfu/ml,50×104 cfu/ml,42×104 cfu/ml;Three groups have a greater number of live bacteria did not increase or decrease, and no significant inhibition. It can be obtained, Lactobacillus for the growth of Aspergillus spores is not inhibited. To the specific activity, the Aspergillus oryzae 3.042 and Lactobacillus CGMCC 1.103 apiece 1 ring, and only spores of Aspergillus 3.0421 for the control group inoculated to the flask containing wheat bran in .When cultured for 68～72h can be seen covered with green spores, its activity can be measured. Activity were: 867.69 U/g, 899.82 U/g, Lactobacillus plantarum that is also inoculated with Aspergillus oryzae, its protease activity compared to inoculation with Aspergillus oryzae, no less obvious, namely, Lactobacillus plantarum starter for the process of Aspergillus oryzae protease in the activity of small, non- will affect the post-fermentation.Optimization using response surface analysis of mixed fermentation conditions for the best starter. The optimum conditions were: starter temperature: 30.81℃; starter time: 104 hours; Aspergillus oryzae and Lactobacillus ratio: 4:1. In this condition, the content of aflatoxin B1: 2.0621μg / kg.The mixed fermentation compared with the single strain fermentation test. Single strain fermentation of the content of aflatoxin B1 in the value of 3,6,9,12 days were: 3.124μg / kg, 3.126μg/kg, 3.133μg/ kg, 3.137μg/kg. When the value of the mixed fermentation were: 2.0616μg / kg, 2.0618μg / kg, 2.0622μg / kg, 2.0623μg /kg, Comparison of the two can be drawn mixed fermentation aflatoxin B1 levels decreased significantly. In addition, the single fermentation and mixed fermentation, the amino nitrogen content were varied between 1.5～1.6, no large increase.
|
PDF Full Text Request