The Effect of Operational Parameters of the Rancimat Method on the Determination of the Oxidative Stability Measures and Shelf-Life Prediction of Soybean Oil
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Operational parameters of the Rancimat method, including oil sample size, airflow rate, and temperature, were evaluated to determine their effects on the oxidative stability index (OSI), temperature coefficient, Q10 number, and shelf-life prediction for soybean oil. Operational parameters of the Rancimat method had statistically significant effects (P < 0.05) on the OSI. Whenever the oil sample size and airflow rate at a given temperature were such that the air-saturated condition could be established, the OSIs showed no statistically significant differences. As temperature increased, OSIs decreased, while their average coefficient of variation (CV) increased. In general, the conditions where the sample was saturated with air and had a relatively lower CV were an oil sample size of 6 g at all temperatures and airflow rates, then 3-g oil sample size at low temperatures (100 and 110 °C) and low airflow rates (10 and 15 L h−1). The temperature coefficient and Q10 number were found to be independent of the oil sample size and airflow rate, and their mean values for soybean oil were calculated to be −3.12 × 10−2 °C−1 and 2.05, respectively. Oil sample size and airflow rate showed a significant effect on shelf-life prediction for soybean oil. Therefore, choosing the right levels of these operational parameters in the Rancimat method may produce the least possible difference between predictions from long-term storage studies and the OSI test.
KeywordsOxidative stability index Q10 number Rancimat Shelf-life prediction Soybean oil Temperature coefficient
The author thanks the Institute of Standards and Industrial Research of Iran (Mashhad branch) for providing research facilities for this work. Furthermore, the author is grateful to S.M.R. Moosavi and A. Heidari for providing the data of the determinations from the Rancimat test.
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