Abstract
There are more than 80% edible vegetable oils (abbreviated as EVB), legally named blending oils, in Taiwan. High price olive oil could provide some fatty acid that cannot be synthesized by human body. Businessmen usually name their products as blended olive oil in order to increase benefit. The composition of these oils is usually different from that of olive oil. The blending percentage of olive oil might also fail to follow the Taiwan regulation. Herein, efforts were taken to statistically analyze both fatty acid composition and fingerprints to establish a system for single EVB identification and blended EVB authentication. The composition information was obtained by microwave-assisted transesterification followed by GC-MS determination. This method was used successfully to establish 31 single EVB fingerprints and 19 blended EVB fingerprints. Discriminant analysis, similarity calculation, and cluster analysis were used to verify the identification system. After establishing the identification system, camellia and olive oil were adulterated with ratio of 10%、20%、30%、40%、50% in soybean oil, canola oil, and sunflower oil as binary and ternary blending oils. The grouping information and adulterating ratio could be obtained by principle component analysis and 2-D trend diagram. We also took efforts to establish a single EVB identification system by nuclear magnetic resonance method to yield 30 single EVB fingerprints and 7 oil species fingerprints. The total analysis time was less than 10 minute and was suitable for rapid screen testing of oil quality.