柑橘汁中游离态和键合态挥发性成分分析

Analysis of free and bound volatile components in citrus juice

比较宽皮柑橘(南丰蜜橘、椪柑)、橙类(脐橙、长叶香橙)、杂柑(爱媛38号、沃柑)和琯溪蜜柚中键合态、游离态香气物质的组成及含量的具体差异,为柑橘类水果制汁的风味特性提供科学依据。结合顶空固相微萃取-气相色谱-质谱联用技术(headspace solid phase microextraction-GC-MS,HS-SPME-GC-MS)对4大类柑橘汁中键合态、游离态挥发性成分进行萃取,并采用主成分分析(principal component analysis,PCA)进行区分辨别。4大类柑橘汁中检出键合态、游离态香气物质共127种,其中烯烃类香气物质种类最多(50种),醇类、醛类、酯类香气物质种类较多(分别为20、19和17种),酮类、酚类香气物质种类则较少(分别为6、5种)。含量方面,烯烃类物质含量最多,占到总柑橘汁样品中香气物质总量的90%以上,其次由高到低分别为醇类、醛类、酯类、酮类、酚类。此外,以4大类柑橘汁为研究对象,对检测到的目标香气物质进行PCA,4大类柑橘汁均可被明显区分开。杂柑中所含游离态香气物质的含量远低于宽皮柑橘和橙类(二者含量相近),远高于琯溪蜜柚。但对于杂柑而言,其所含的游离态香气物质种类却较为丰富,其中以爱媛38号最为丰富,且远高于其他柑橘品种(其他柑橘品种所含游离态香气物质种类数相近)。此外,宽皮柑橘所含键合态香气物质的种类数最多,其次为橙类和杂柑(二者种类数相近),琯溪蜜柚最少。

The aim of this study was to compare the specific differences in the composition and content of free and bound aroma substances in wide peel citrus(Nanfeng,Ponkan),oranges(Qichen,Changyexiangchen),hybrid citrus(Aiyuan 38,Wogan)and Guanxi Honey Pomelo,in order to provide a scientific basis for the flavor characteristics of citrus fruit juice.Headspace solid-phase microextraction gas chromatography-mass spectrometry(HS-SPME-GC-MS)was used to extract the volatile components from the four citrus juices,and principal component analysis(PCA)was used to distinguish them.A total of 127 bound and free aroma substances were characterized in the four categories of orange juice,among which olefins yields were the highest(50);alcohols,aldehydes and esters were the second(20,19 and 17 respectively);ketones and phenols were less(6 and 5 respectively).In terms of content,the olefins yield in the total aroma substances from the total orange juice samples were more than 90%,followed by alcohols,aldehydes,esters,ketones and phenols,respectively.In addition,the four categories of citrus juice were taken as the research object,and the target aroma substances were analyzed by principal component analysis.The four categories of citrus juice could be distinguished by PCA analysis.The content of free aroma substances in hybrid citrus was much lower than wide peel citrus and orange(their content was similar),and much higher than guanxi pomelo.However,the free aroma substances contained in hybrid citrus were rich,and among which Aiyuan 38 was the most abundant,and was much higher than other citrus varieties(the number of free aroma substances contained in other citrus varieties was similar).In addition,broad peel citrus contained the most kinds of bonded aroma compounds,followed by orange,while Guanxi pomelo was the least.