The Medical 1H-MRS Analysis of Edible Vegetable Oils Rancidity: Focus on the Saturated/Unsaturated Fatty Acids (Bond) Change

Resumo

The purpose of this study was to investigate the usefulness of medical magnetic resonance spectroscopy analysis methods for assessment of edible oil rancidity. The four edible oils including soybean oil, olive oil, grape seed oil, and sunflower oil were selected for evaluating rancidity (cooking counts/time, exposure time in air). The total lipid ((–CH₂–)_n/noise), total saturated fatty acid (TSFA), total unsaturated fatty acid (TUSFA), total unsaturated bond (TUSB), and polyunsaturated bond (PUSB) were quantified by separating each peak area of –CH₃, (–CH₂–)_n, –CH₂–C=C–CH₂–, =C–CH₂–C=, and –CH=CH– by –CH₃ by ¹H-magnetic resonance spectroscopy (MRS) analysis. The change in fatty acid (bond) according to the cooking counts/time increased for all fatty acids (bond) in soybean oil and grape seed oil. In olive oil, all fatty acids (bond) decreased overall, while sunflower oil showed a decrease in TSFA and PUSB and an increase in TUSFA and TUSB. The soybean, grape seed, and sunflower oils showed increased TUSB, TUSFAB, and PUSB with exposure to air after cooking once, while olive oil showed hardly any changes in fatty acids according to the exposure time to air after cooking. It will be necessary to choose a method that minimizes changes in fatty acids by fully understanding the characteristics of the selected edible oil to prevent not only a change in fatty acids during cooking, but also an increase in TSFA.