Degradation Of Endogenous And Exogenous Genes Of Fermented Transgenetic Roundup Ready Soybean Products During Fermentation Processing

The safety of GM food has become one of the key issue dominating public concern.For the importance of close ties between genetically modified crops and food chain, ananlyzing the course of manufacturing processes and tracing the origin to establish China's traceability and pollution assessment system of transgenic soybean and its products.It can also provide scientifical evidence and research basement for the identification, regulation and protection of consumer's right of GM products.In this study, genetically modified soybean and its fermented products are used to study object.By comparison, we found that the kit is more suitable to use to extract DNA from related products, and the qualitative PCR method is used to detect the sample's endogenous and exogenous genes.At last, we found fermented bean curd and gray tofu contained genetically modified ingredients.We used different primers for PCR test and found that by testing 200bp fragments and simultaneously detecting Lectin,35S,NOS and EPSPS genes,the results are more reliable and we can greatly reduced the probability of negative results.Through these methods, we established a reliable detection system to determine if the sample contained genetically modified ingredients. We used Rhizopus oligosporus and Bacillus subtils natto to simulate the processes of fermentation to study the change of endogenous and exogenous genes in the whole process and the relationship with associated microbial enzyme activity preliminarily.The results showed that:The endogenous and exogenous genes were severely degraded after high temperature treatment. The degradation of endogenous and exogenous genes wasn't obvious at the beginning of the fermentation process, but after a long time of fermentation treatment, the endogenous and exogenous genes degraded gradually. The change of the relative content of genetically modified ingredients in the process of fermentation showed that:Relative content of genetically modified ingredients decreased after high-temperature cooking, then with the process of fermentation, the relative content of genetically modified ingredients gradually increased to the highest at the second day of fermentation and after that the content gradually decreased. Related nuclease, lipase and protease activities of soybeans were lost after high-temperature cooking and gradually increased with the growth of microorganisms. The activities of nuclease and lipase were highest at the second day of fermentation, and the activity of protease was highest at the third day of fermentation. Then the nuclease, lipase and protease activities began to decrease but still remained at a relatively high level.