Identification of Common Adulterants in Walnut Beverage Based on Plant DNA Barcode Technology

Walnut beverage is a common vegetable protein drink that is rich in proteins and has a wide consumption market. In this study, a plant DNA barcode technology was used to establish a method to identify common adulterated ingredients (peanut and soybean) in walnut beverage. In this experiment, universal primers were designed, and PCR amplification was performed. The universal primers were screened by sequencing and comparing the amplified products. Results showed that the primers rbcL-4 and matK-4 amplified walnut, peanut, sesame, soybean, and hazelnut. Peanut genomic DNA and soybean genomic DNA were added to the genomic DNA of walnut in different proportions. Primer rbcL-4 can detect 10% peanut genome DNA, and primer matK-4 can detect 10% soybean genome DNA. Calculation results of the extraction rate revealed that primer rbcL-4 can detect 8.88% peanut raw materials and primer matK-4 can detect 2.30% soybean raw materials. The combination of these two primers can be used as a universal primer for the identification of adulterated components in walnut beverage. This experiment could serve as a theoretical reference for related research and detection.