Rapid and duplex detection of sweetpotato and maize components in starch products using Proofman-LMTIA method
Pengfei Cui, Zhenqing Hu, Mengru Guo, Yongzhen Wang, Dandan Xu, Wei Yao, Jinxin Liu, Chunmei Song, Juntao Sun, Fugang Xiao, Deguo Wang
Abstract
To simultaneously detect sweetpotato and maize components in starch products, this study develops a rapid analysis method based on ladder-shape melting temperature isothermal amplification (LMTIA) coupled with proofreading enzyme-mediated probe cleavage (Proofman). Internal transcription spacer (ITS) gene sequences were targeted to design species-specific primers linked with Proofman probes. The detection of this duplex Proofman-LMTIA method could be completed in 20 min under the optimal temperature of 61 ℃. The specificities of sweetpotato and maize ITS primers were verified with seven other species. The sensitivities of sweetpotato and maize DNA extracts were 10 pg/μL and 1 pg/μL, respectively. The detection limits of sweetpotato and maize DNA samples extracted from artificially adulterated starch powders were both 1 %. To demonstrate the effectiveness of the established duplex Proofman-LMTIA method, a total of 19 commercial sweetpotato noodles and 14 starch products were collected and tested for sweetpotato and maize authentication. Taken together, the LMTIA method is suitable for rapid and accurate detection of sweetpotato and maize components in starch products. The popularization of this method will provide guidelines for ingredients authentication and market supervision of products.