Distribution and degradation of DNA during industrial soybean oil processing

Abstract

In recent years, soybean has become the most widely grown genetically modified (GM) crop worldwide, and the most extensive manner of transgenic soybean processing is oil production. Determining the distribution and degradation of DNA during oil processing can facilitate the detection, monitoring, and traceability of GM soybean. In this study, we systematically sampled industrial soybean oil extraction and refining processes and performed ultraviolet spectrophotometry, real-time polymerase chain reaction (PCR), atomic force microscopy, and qualitative PCR to evaluate the DNA status. The results indicated that the DNA concentrations in soybean seeds, kernels, conditioned soybean, laminated soybean, extracted soybean, and meal (2.035 × 106–2.682 × 106 ng/g) were significantly higher than those in crude oil (194.800 ng/g) and in subsequently refined oils (0.026–0.664 ng/g) (P < 0.05). Organic solvent extraction and degumming were the two main steps in removing DNA from refined soybean oil. Combined treatment with organic solvent and heating (110 °C) and heating at 240–250 °C were key steps in degrading lectin and cp4epsps during industrial soybean oil processing. Our analyses of the DNA status during soybean oil processing will contribute to the detection, traceability, and labelling of GM soybean.