Use of solid phase microextraction to identify volatile organic compounds in brazilian wines from different grape varieties

Abstract The Brazilian wine industry has shown significant growth in recent years and the insertion of new concepts, such as geographical indications as signs of quality, has placed Brazil in tune with the tendencies of world wine production. The aim of this work was to apply the Solid Phase Microextraction technique in combination with Gas Chromatography-Mass Spectrometry to study Brazilian wines made from different grape varieties, in order to separate and identify their volatile organic compounds. These substances were identified by comparisons between the spectra obtained with those presented in the NIST library database, and by comparisons with linear retention indices and literature data. The amounts of the compounds were calculated based on the total peak areas of the chromatograms. Forty-seven volatile compounds were identified and grouped into alcohols, aldehydes, fatty acids, esters, hydrocarbons, ketones and terpenes. Most of them belonged to the ester function, conferring a fruity aroma on the wines. The alcohols may have originated from the yeast metabolism, contributing to the alcoholic and floral aromas. Ethyl lactate, 1-hexanol and diethyl maleate were identified in all the varieties, except Merlot. Decanal, methyl citronellate, (E)-2-hexenyl-3-methylbutyrate were only found in Merlot, while 2,3-butanediol was only present in the Tannat wines. 2-Phenylethanol was present in all varieties and is recognized as giving pleasant rose and honey attributes to wines. This study showed that the volatile profile of red wines is mainly characterized by esters and higher alcohols. The statistical analysis of the comparison of averages showed a greater amount of averages significantly different in the relative areas of Merlot wine. The Principal Component Analysis showed one grouping composed only of the Merlot wine samples, and this was probably related to the existence of the volatile organic compounds that were specifically identified in these wines.

摘要 巴西葡萄酒产业近年来呈现显著增长态势，诸如地理标志这类彰显品质的新概念的融入，令巴西与世界葡萄酒生产的发展趋势保持同步。本研究旨在将固相微萃取（Solid Phase Microextraction）技术结合气相色谱-质谱联用法（Gas Chromatography-Mass Spectrometry），对不同葡萄品种酿制的巴西葡萄酒展开研究，以分离并鉴定其中的挥发性有机化合物。上述物质通过将所得质谱与NIST库数据库（NIST library database）中的谱图进行比对，并结合线性保留指数与文献数据完成鉴定。化合物的含量基于色谱图的总峰面积进行计算。本研究共鉴定出47种挥发性化合物，可归类为醇类、醛类、脂肪酸、酯类、烃类、酮类以及萜类。其中绝大多数属于酯类物质，可为葡萄酒赋予果香香气。醇类物质可能源自酵母代谢，有助于赋予葡萄酒酒香与花香风味。除梅洛（Merlot）葡萄酒外，乳酸乙酯、1-己醇与马来酸二乙酯在所有受试葡萄品种的酒样中均被检出。癸醛、甲基香茅酯、(E)-2-己烯基-3-甲基丁酸酯仅在梅洛葡萄酒中被发现，而2,3-丁二醇仅在塔那（Tannat）葡萄酒中存在。2-苯乙醇在所有品种的酒样中均有检出，其被认为可赋予葡萄酒愉悦的玫瑰与蜂蜜香气。本研究表明，红葡萄酒的挥发性成分特征主要体现为酯类与高级醇。均值比较的统计分析结果显示，梅洛葡萄酒的相对峰面积存在更多具有显著差异的均值。主成分分析（Principal Component Analysis）结果显示存在一个仅由梅洛葡萄酒样本组成的聚类，这一现象大概率与该类酒样中特有的挥发性有机化合物的存在相关。