A few years ago, the demand for natural Chinese garlic oil far outweighed the available supply, resulting in some garlic oils being sold as 'natural' when in fact they were adulterated through the addition of various amounts of synthetic volatile compounds. The current methodology to test for adulteration in garlic oil consists of radionuclear analyses, i.e. 14C and stable isotope ratio measurements. By detecting volatile compounds by GC-FID (flame ionization detection), and by using PCA (principal component analysis) and MLR (multiple linear regression) chemometric data processing, we developed a simple yet rugged way to measure adulteration level in garlic oil samples of Chinese origin. This new method showed good correlation with adulteration results from radionuclear assays, thus providing a cost-effective means of confirming the natural authenticity of garlic oils of Chinese origins. Our work indicated that adulteration occurred when synthetically prepared diallyl disulfide, diallyl trisulfide or diallyl tetrasulfide were either combined together or added in various amounts to a lower quality garlic oil.

Detecting and predicting adulteration in Chinese garlic oil by gas chromatography analysis and chemometrics

240th National Meeting (2010)

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