基于主成分分析的植物油煎炸品质评价Evaluation of frying quality of vegetable oils based on principal component analysis

旨在为植物油煎炸品质的综合评价提供参考，对市场上常见的6种植物油（大豆油、菜籽油、棕榈油、玉米油、葵花籽油和棉籽油）进行煎炸实验，考察煎炸过程中植物油的总极性组分(TPC)含量、酸值（AV）、过氧化值（POV）、p-茴香胺值（p-AV）、脂肪酸和碘值等常规理化指标，（E,E）-2,4-癸二烯醛含量，黏度和色泽以及维生素E（VE）和植物甾醇含量的变化，分析各指标的两两相关性，并对11项检测指标进行主成分分析（PCA）。结果表明：6种植物油煎炸过程中11项指标的变化存在一定差异，随着煎炸时间的延长，煎炸油的TPC含量、AV、POV、p-AV、红值和黏度不断增加，C18∶ 2与C16∶ 0比值、碘值、VE和植物甾醇含量不断降低，（E,E）-2,4-癸二烯醛含量先增加后降低；不同指标之间存在一定的相关性，其中TPC、AV和黏度两两之间呈极显著正相关，C18∶ 2与C16∶ 0比值、碘值与VE含量两两间存在极显著的正相关性,（E,E）-2,4-癸二烯醛含量与p-AV呈极显著正相关;PCA得到的3个主成分的累积贡献率为86.225%，通过计算3个主成分的加权得分建立了煎炸油的综合评价模型，并通过计算得出6种植物油中棕榈油的煎炸稳定性最好。综上，所建立的煎炸油综合评价模型可以对6种植物油煎炸品质进行评价，棕榈油的煎炸品质最好。Aiming to provide a reference for the comprehensive evaluation of the frying quality of vegetable oils, frying experiments were carried out on six common vegetable oils available in the market (soybean oil, rapeseed oil, palm oil, corn oil, sunflower seed oil, and cottonseed oil) to investigate the total polar component (TPC) content, acid value (AV), peroxide value (POV), p-anisidine value (p-AV), fatty acid and iodine value conventional physicochemical indexes, the content of (E,E)-2,4-decadienal, viscosity and colour, and the contents of vitamin E (VE) and phytosterols of vegetable oils during the frying process were detected to analyse the two-by-two correlation of the indexes, and the 11 tested indexes were subjected to the principal component analysis (PCA).The results showed that there were some differences in the changes of 11 indexes during the frying process of six vegetable oils. With the prolongation of frying time, the TPC content, AV, POV, p-AV, red value and viscosity of the frying oils increased, the ratio of C18∶ 2 to C16∶ 0, iodine value and contents of VE and phytosterol decreased, and the content of (E,E)-2,4-decadienal first increased and then decreased. There were some correlations between them, including highly significant positive correlations between TPC, AV and viscosity, and highly significant positive correlations between the ratio of C18∶ 2 to C16∶ 0, iodine value and the content of VE. There were highly significant positive correlation between the (E,E)-2,4-decadienal content and p-AV. The cumulative contribution rate of the three principal components obtained was 86.225%, and a comprehensive evaluation model of frying oils was established by calculating the weighted scores of the three principal components. The frying stability of palm oil was the best among the six vegetable oils. In conclusion, the frying quality can be evaluated by the established comprehensive evaluation model of frying oil, and the frying quality of palm oil is the best.