基于主成分分析法分析超高压处理对黄瓜水香气的影响

采用顶空固相微萃取与气相色谱-质谱仪联用技术对超高压处理前后黄瓜水的香气成分进行测定,并应用主成分分析法对超高压黄瓜水的香气成分进行分析。结果表明,从黄瓜水中检测出33种香气成分,主要是醇类和醛类,其中含7种特征性香气成分,(E,Z)-2,6-壬二烯醛含量最高,占香气总量的27.23%;通过主成分分析法得出,第1主成分的贡献率为65.67%,第2主成分的贡献率为27.71%,前两个主成分的累积贡献率达到93.38%,可代表超高压黄瓜水香气变化趋势。不同超高压处理的黄瓜水分为3个类型是由于超高压处理对第2主成分的影响造成的,未高压处理黄瓜水单独分为一类是由于超高压处理对第1主成分和第2主成分的共同影响造成的,表明采用主成分分析法作为超高压黄瓜水香气品质的客观评价方法是可行的。

Effect of Ultra-high Pressure Treatment on Aroma Compounds in Cucumber Water Analyzed by Principal Component

In this study, the aroma components in cucumber water before and after ultra high pressure (UHP) treatments were investigated by solid phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS) combined with principal component analysis. The results showed that 33 aroma components in cucumber water were detected and the majorities were alcohols and aldehydes. Seven of them were characteristic, and the content of (E,Z)-2,6-nonadienal was the highest, accounting for 27.23% of the total aroma components. The results of the principal component analysis showed that the rate of the first and second principal components was 65.67% and 27.71%, respectively. The cumulative rate of the first and second principal components was 93.38%, which was stand for the change of aroma components in cucumber water. The cucumber water treated by different ultra high pressures was divided into three groups, due to the effect of the different pressures to the second principal component. The untreated cucumber water was separated from the three groups because of the different pressure treatments to the first and second principal components. Thus, principal component analysis was feasible to study the aroma components in cucumber water treated by ultra high pressure.