Abstract:The effects of different treatment conditions on oil quality were studied by using acid value (AV), peroxide value (POV), fatty acid composition and rheological properties. Under different treatment conditions, both AV and POV showed an increasing trend with time. The AV and POV of the high temperature cooking group and the light storage group above 200 ℃ were higher than those of the microwave treatment group and the high temperature storage group, respectively. With the increase of cooking temperature and illumination, the AV and POV increased rapidly, and their highest values were reached under the processing conditions, 1.17 mg/g and 22.75 mmol/kg, respectively; treatment time and treatment temperature, heat treatment method and light had an effect on fatty acid content, and the change trend was not nearly the same. Long-term treatment at high temperature reduced the content of oleic acid and linoleic acid. After treatment at 300 ℃ for 20 min, the content of oleic acid and linoleic acid decreased from 38.94% and 31.46% to 37.76% and 30.53%, respectively, while the content of linolenic acid increased from 0.26% to 0.28%, and the content of EPA and DHA polyunsaturated fatty acids also increased. For the long-term storage under high temperature and light conditions, the above unsaturated fatty acid content was reduced; the rheological properties of the oil after different conditions were not changed with the change of shear force for the high temperature cooking group and the microwave group above 200 ℃. The viscosity of fat increased with the increase of treatment time, and then decreased. The viscosity of the oil in the storage group increased with the treatment time.
