摘要
为探讨菜籽油热氧化过程中荧光光谱特征的变化规律,采用平行因子分析方法结合二维相关技术解析菜籽油的三维同步荧光光谱,并与油脂氧化化学指标进行相关分析。结果表明:菜籽油具有叶绿素a的荧光特征(Δλ=10 nm,λex=674 nm)和叶绿素b的荧光特征(Δλ=60 nm,λex=620 nm);热氧化过程中,产生了(Δλ=60 nm,λex=448 nm)的特征同步荧光峰。双因子的平行因子分析表明:Δλ为10和60 nm的同步荧光光谱分别为第一、第二主要成分,分别对应叶绿素a和油脂氧化产物的荧光特征;随着热氧化时间的延长,叶绿素a的同步荧光强度降低,而油脂氧化产物的同步荧光强度逐渐升高。二维相关分析表明,叶绿素a热氧化速度、叶绿素b热氧化速度、油脂氧化产物生成速度依次降低。代表叶绿素氧化程度的SFI674和代表油脂氧化产物产量的SFI448与油脂氧化化学指标具有良好的相关性。因此,同步荧光光谱可作为衡量食用油热氧化劣变的指标。
The variation of the fluorescent characteristics of rapeseed oil during thermal oxidation was studied by using parallel factor analysis（PARAFAC） method and two-dimensional correlation technique.The results showed that rapeseed oil had two synchronous fluorescence peaks,one was at λex 674 nm and Δλ 10 nm,assigned to the fluorescent characteristics of chlorophyll a;the other was at λex 620 nm and Δλ 60 nm,corresponding to chlorophyll b.During thermal oxidation,the fluorescent characteristics,λex 448 nm and Δλ 60 nm,of oil oxidation product formed.Two-factor PARAFAC model was optimized for three-dimensional synchronous fluorescence landscapes of 14 samples by using core-consistence and explained variance diagnosis.The profiles of 1st and 2nd main components had an optimal λex 674nm and Δλ 10 nm and λex 448 nm and Δλ 60 nm,respectively.During thermal oxidation,the synchronous fluorescence intensity of chlorophyll a gradually decreased,while the synchronous fluorescence intensity of oil oxidation product gradually increased.Thermal oxidation time was used as the external perturbation variable,the results of two-dimensional correlation synchronous fluorescence spectroscopic technique showed the variation ratio of fluorescence intensity of chlorophyll a,chlorophyll b and oil oxidation product decreased in turn.Thermo-oxidative alterations of rapeseed oil were measured through wet chemistry methods： p-anisidine value,peroxide value,acid value,and conjugated diene.Both the synchronous fluorescence intensity at λex 674 nm and Δλ 10 nm（SFI674）,and the synchronous fluorescence intensity at λex 448 nm and Δλ 60 nm（SFI448）,had a higher correlation with wet chemical index.Thus,synchronous fluorescence could be used as the index of oil thermal oxidation.
出处
《分析化学》
SCIE
EI
CAS
CSCD
北大核心
2013年第9期1373-1377,共5页
Chinese Journal of Analytical Chemistry
基金
国家自然科学基金项目(No.30901129)
安徽省自然科学基金项目(No.1208085QC69)资助
关键词
平行因子分析
二维相关技术
热氧化
三维同步荧光光谱
菜籽油
Parallel factor analysis
Two-dimensional correlation
Thermal oxidation
Three-dimensional synchronous fluorescence spectroscopy
Rapeseed oil
