为研究浅渍黄瓜贮藏过程中风味物质的变化规律,采用电子鼻和气相色谱-离子迁移谱技术(gas chromatography-ion mobility spectrometry,GC-IMS)分析浅渍黄瓜的挥发性化合物.电子鼻和GC-IMS分析表明,浅渍黄瓜贮藏过程中风味特征发生了显著变化.GC-IMS共定性分析出56种挥发性化合物(volatile organic compounds,VOCs),包括醇类10种、醛类30种、酮类8种、酯类5种、呋喃1种、酸类1种、烷烃类1种.随着贮藏期的延长,醛类、醇类和酮类物质的相对含量显著减少,酯类物质显著增加(P＜0.05).经相对气味活度值(relative odor activity value,RO AV)计算,筛选出9种RO AV ≥ 1的化合物,被认为是浅渍黄瓜的关键风味化合物.进一步对不同贮藏期样品的关键风味化合物进行偏最小二乘法判别分析,筛选出6种变量重要投影值(variable important for the projection,VIP)大于1的差异标志物,分别是顺-6-壬烯醛、壬醛、1-戊烯-3-酮、异丁醛、反,顺-2,6-壬二烯醛、反-2-辛烯醛.其中反-2-辛烯醛的相对含量随着贮藏时间的延长而增加,可能是导致后期风味劣变的主要原因.本研究通过对浅渍黄瓜贮藏期间风味变化规律的分析,可为浅渍黄瓜贮藏过程的风味品质评价提供理论依据.
Abstract
In order to investigate changes in flavor substances of lightly-pickled cucumbers during storage,volatile compounds were analyzed by electronic nose and gas chromatography-ion mobility spectrometry(GC-IMS).The results showed that flavor characteristics of lightly-pickled cucumbers changed obviously during storage.A total of 56 volatile organic compounds(VOCs)were detected by GC-IMS,including 10 alcohols,30 aldehydes,8 ketones,5 esters,1 furan,1 acid,and 1 alkane.With the extension of storage period,the relative contents of aldehydes,alcohols and ketones decreased significantly,while the contents of esters increased significantly(P＜0.05).Based on relative odor activity value(ROAV≥1),9 key flavor compounds were found.The key flavor compounds were performed by PLS-DA and 6 differential markers were screened(VIP＞1),including cis-6-nonenal,nonenal,l-penten-3-one,isobutyraldehyde,trans-2,cis-6-nonadienal,and trans-2-octenal.Among them,trans-2-octenal increased with the relative extension of storage time,which might be the main off-flavor compound for flavor deterioration.This study can provide a theoretical basis for flavor quality evaluation of lightly-pickled cucumbers during storage.
维普
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