Comparison of Carbon Stable Isotope and Fatty Acid Analyses for the Authentication of Perilla Oil

Perilla oils distributed in Korea are authenticated by analyzing their 13C/12C isotope ratios (expressed as δ13C) or fatty acid compositions. No significant differences are found in the δ13C values of authentic (n = 27) and adulterated (n = 10) perilla oils, whereas the distributions of 11 fatty acids (FAs) are significantly different in these oils. By using orthogonal projections for latent structures discriminant analysis (OPLS‐DA) technique, the 18:2n‐6, and 18:3n‐3 content levels are determined to be the best variables for authenticating perilla oil. The authenticity of 7 out of 76 blind samples are identified through δ13C values, whereas using the 18:2n‐6 and 18:3n‐3 content levels can identify the authenticity of 66 blind samples. These results suggest that fatty acid analysis is a more useful procedure for determining the perilla oil authenticity. A blind trial shows that perilla oils adulterated with corn, soybean, or perilla‐flavored oil at concentrations ≥5 vol% can be distinguished. Practical applications: Public concern about economically motivated adulteration (EMA) of food is growing worldwide. Perilla oil is a targeted product for EMA in Korea due to its high retail price. This study provides the first evidence showing that 18:2n‐6 and 18:3n‐3 content levels can become new specifications and standards for perilla oils distributed in Korea. The present study develops a procedure for authenticating perilla oils on the basis of the range of linoleic and α‐linolenic acid content levels. The procedure can correctly identify perilla oils adulterated with corn, soybean, or perilla‐flavored oil at concentrations ≥5 vol%. The present study develops a procedure for authenticating perilla oils on the basis of the range of linoleic and α‐linolenic acid content levels. The procedure can correctly identify perilla oils adulterated with corn, soybean, or perilla‐flavored oil at concentrations ≥5 vol%.