Perilla oil is a targeted product for economically motivated adulteration in Korea due to its high retail price. The aim of the first study was to authenticate perilla oils distributed in Korea by analyzing their δ13C values or fatty acid (FA) compositions. No significant differences were found in the δ13C values of authentic and adulterated perilla oils, whereas the distributions of 11 FAs were 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 were identified through δ13C values, whereas using the 18:2n-6 and 18:3n-3 content levels identified the authenticity of 66 blind samples. These results suggest that FA 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. The aim of the second study was to authenticate perilla oils using their Fourier-transform infrared spectroscopy (FT-IR) spectra with attenuated total reflectance accessory. By using OPLS-DA technique, the =C–H cis-double bond, –C–H asymmetric, and –C–H symmetric stretching are determined to be the best variables for authenticating perilla oil. Significant differences existed in the integration and second derivative values of all three FT-IR peaks between authentic and adulterated perilla oil samples. The procedure for applying the second derivative range of variables found in authentic perilla oil samples distinguished perilla oils adulterated with corn or soybean oil at concentrations ≥5 vol%. These results suggest that FT-IR analysis is a useful and cost-effective procedure for determining the perilla oil authenticity.

Targeted analytical methods for the authentication of perilla oil: Fatty acid, stable isotope, and FT-IR analysis approach

2019 Spring National Meeting

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