Oxidation degree of soybean oil at induction time point under Rancimat test condition: Theoretical derivation and experimental observation.

Xu Li, Yongru Li, Fan Yang, Ruijie Liu, Chenwei Zhao, Qingzhe Jin, Xingguo Wang

Journal: Food research international (Ottawa, Ont.) 2020;120():756-762

PMID: 31000295

Full Text on Elsevier Science View on PubMed

Abstract

Indices including conductivity, short-chain carboxylic acids, total polar material, acid value, peroxide value and fatty acid composition in water or oil were monitored during Rancimat test of soybean oil from 90 °C to 120 °C. Formic, acetic, propionic and butyric acids in water were detected by ion chromatography. The results showed that all indices had two-stage oxidation rates of initiation (k) and propagation (k) at each temperature. Induction period (IP) computed from conductivity and other indices were well correlated (R = 0.9980-0.9999). According to the Arrhenius model and empirical equation, k increased exponentially with temperature (T) while IP decreased exponentially with T. Oxidation degree of oil at induction time point IP*k was found to be independent of heating time and temperature. The transition between two models was theoretically derived and proved by H NMR. Evaluation of IP*k may provide a new route to correlate Rancimat data with shelf life of edible oil.

Address: International Joint Research Laboratory for Lipid Nutrition and Safety at Jiangnan University, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, PR China.; International Joint Research Laboratory for Lipid Nutrition and Safety at Jiangnan University, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, PR China. Electronic address: [email protected].

DOI: 10.1016/j.foodres.2018.11.036

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MeSH Terms: Hot Temperature, Oxidation-Reduction, Soybean Oil, Time