Effects of simulated different cooking temperatures on the quality of Korean pine seed oil and principal component analysis

ObjectiveIn order to explore the changes of fatty acid composition and physicochemical properties, Korean pine seed oil was heated at simulated cooking temperatures, and to reveal comprehensive evaluation by the principal component analysis method.

MethodTo determine the fatty acid composition of Korean pine seed oil pre-treated at different cooking temperatures, gas chromatography-mass spectrometry (GC-MS) was used. The physical and chemical properties of Korean pine seed oil before and after heat treatment were measured according to the national standard, and the fatty acid composition of Korean pine seed oil treated at different temperatures was analyzed by SPSS19.0 software.

ResultWith the increase of heat treatment temperature, the carbonyl value and acid value of Korean pine seed oil increased significantly (P < 0.05), the peroxide value increased firstly and then decreased, reaching the maximum value of 9.79 mmol/kg at 180 ℃, and the iodine value and saponification value decreased respectively by 31.78% and 22.86% compared with control. The types and contents of fatty acids in Korean pine seed oil changed significantly after high temperature heating. The contents of unsaturated fatty acids, linoleic acid and pinolenic acid decreased, while the types and contents of trans fatty acids increased with cooking temperature. Five fatty acids (9t-C_18∶1, (9c, 11t)-C_18∶2, (10t, 12c)-C_18∶2, 14-methyl-C_16∶0, 10c-C_17∶1) were synthesized during heating. Two principal components were extracted when analyzing the fatty acid composition of Korean pine seed oil treated at different temperatures through principal component analysis. The variance contribution rates were 83.80% and 10.43%, respectively.

ConclusionIt is suggested that raising temperature can reduce the quality and fatty acid composition of Korean pine seed oil. The physical and chemical indexes and fatty acids of Korean pine seed oil do not change significantly during low temperature heat treatment.With the increase of temperature, the content of polyunsaturated fatty acids decreased, and the types and contents of trans fatty acids increased in Korean pine seed oil.