Abstract
There are many kinds of plant oils, such as soybean oil, peanut oil, sesame oil and camellia oil, which are common oils in Taiwan. Unscrupulous businessmen adulterate high-price oils with low-price oil to seek high profit, and which greatly damage the rights, interests and even health of consumers. To protect consumers and defeat the adulteration of commercial oils, this study was going to establish an authenticating system of plant oils. In order to make oil pretreatment fits the rule of green chemistry, microwave–assisted methylation was successfully applied. GC-MS was used to analyze fatty acid in oils qualitatively and establish 30 sample standard fingerprints and 11 species standard fingerprints. Discrimination analysis, similarity analysis, cluster analysis and the innovated 2-D diagram analysis of this study were trained and established by the fingerprints. After setting up these four analysis systems, camellia oil and black sesame oil were adulterated with ratio of 10%、25%、40%、50% of soybean oil as adulterated oil samples that were used to do the validation and application of adulterations of four systems. It shows that both cluster analysis and 2-D diagram analysis have better results, and latter can further get adulterated ratio of samples. Limit of authentication (LOA) of adulterated camellia oil and black sesame oil is 0.73% and 1.94%. In this study, we successfully established an authenticating system of plant oils by combining two analysis systems, and which could be utilized for adulterating ratio evaluated.