基于理化指标及主成分分析的葵花籽油品质综合评价指标的建立

Establishment of Comprehensive Indexes Used to Evaluating Sunflower Oil Quality Based on Physicochemical Indicators and Principal Component Analysis

研究了105℃和180℃氧化条件下葵花籽油理化指标(过氧化值、共轭二、三烯、茴香胺值、酸价、碘值和极性化合物)的变化规律,就理化指标对油脂总体品质变化的贡献度进行了主成分分析,建立了可有效表征葵花籽油在相应条件下品质变化的综合评价指标。结果表明:随着氧化时间的延长、温度的升高,共轭二、三烯、茴香胺值、酸价和极性化合物的升高趋于显著(P≤0.05),而碘值则均呈下降趋势;通过对各理化指标的总体变化率以及与油脂不饱和度和常用理化指标的相关性分析,发现过氧化值、共轭二烯、茴香胺值(105℃)或共轭二烯、茴香胺值、极性化合物(180℃)可有效表征葵花籽油的品质变化;成功建立了评判葵花籽油品质变化的综合指标,并确定其临界值分别为-0.189(105℃)和0.727(180℃);此外,可通过对共轭二烯和茴香胺值的主成分分析有效区分在105℃或180℃下氧化葵花籽油的品质变化。

It is important to establish comprehensive indexes for evaluating oil quality and ensure the safety of edible oils. The physicochemical indicators（ e. g. peroxide value,conjugated diene,conjugated triene,anisidine value,acid value,iodine value,total polar compound） of sunflower oil oxidized at 105 ℃ and 180 ℃ were investigated firstly,then the oil quality evaluation model were developed by the principal component analysis（ PCA）,and the contributive degree of physicochemical indicators to sunflower oil quality was compared. The comprehensive indexes for sunflower oil quality monitoring and evaluation at 105 ℃ and 180 ℃ were implemented by the PCA model. The results indicated that conjugated diene（ K232）,conjugated triene（ K270）,β-anisidine value（ PAV）,acid value（ AV） and total polar compound（ TPC） increased significantly（ P ≤0. 05） during the oxidation process,while the iodine value（ IV） decreased and the peroxide value（ POV） fluctuated. After taking over the overall rate of change（ ORC） of all physical and chemical indicators and correlations between the physicochemical indexes and UFA/SFA（ UFA- unsaturated fatty acid,SFA- saturated fatty acid）,peroxide value（ 105 ℃） or total polar compound（ 180 ℃）,indicators（ 105 ℃/peroxide value,conjugated diene,anisidine value; 180 ℃ ： conjugated diene,anisidine value,total polar compound）were chosen to judge the sunflower oil quality accurately. Comprehensive indexes were achieved by PCA based on information fusion,and the critical value is- 0. 189（ 105 ℃） and 0. 727（ 180 ℃）,respectively. On the other hand,conjugated diene and anisidine value could be used to distinguish well the sunflower oils oxidized under different temperatures（ 105 ℃ and 180 ℃） based on PCA.