Microwave resonator can help to predict oxidative stability in C18-based vegetable oils.

Effects of moisture content, degree of oxidation, degree of unsaturation of fatty acid compositions in C18-based edible oils were determined by a microwave resonator in the range of 0-4.4 GHz. Moisture content and degree of oxidation in corn oil made difference in signal intensity at 1.7-1.9 GHz and 1.0-1.2 GHz, respectively without uniform trend in signal intensity. Degree of unsaturation of C18-based edible oils including corn, sesame, soybean, olive, perilla, and flaxseed oils provided difference in 3.0-3.1 GHz with a dependent manner of degree of unsaturation. Average of signal intensity (ASI) in 3.0-3.1 GHz had high correlation (R > 0.93) to the degree of unsaturation in edible oils. Oils with high oleic acid had relatively low ASI while those with high linolenic acid had high ASI value. Oxidative stability of C18-based edible oils can be categorized successfully without fatty acid analysis using a microwave resonator.