A quantitative detection of mung bean in chestnut paste using duplex digital PCR

Highly manufacturing process of chestnut paste leaves a considerable space for Economically Motivated Adulteration (EMA) with cheaper ingredients such as mung bean. In this paper a novel quantitative detection of mung bean in chestnut paste using duplex digital PCR was reported. Two sets of primers and probes were designed according to mung bean and chestnut specific genomic genes suitable for duplex droplet digital PCR (ddPCR) and duplex chip digital PCR (cdPCR) to set up a mass ratio quantitative detection method for mung bean, a common alternative plant-derived ingredient in chestnut paste products. The manufacturing process of chestnut paste products was considered to establish the linear relationship formula between mass ratio and gene copy number (CN) ratio of the two ingredients. The limits of quantification for gene CN concentrations (LOQ(copy)) of mung bean and chestnut were both 6 copies/μL, at the same time a mass ratio of mung bean in chestnut paste range from 5% to 80% was able to be quantified accurately to provide technical support for the identification of fraudulent substitution or adventitious contamination.