Analysis of volatile aroma components in berries and wines of different ‘Cabernet Sauvignon’‘Merlot’and‘Cabernet Franc’clones

Abstract:【Objective】‘Cabernet Sauvignon’,‘Merlot’and‘Cabernet Franc’are excellent wine grape varieties. Selection of clonal line is one of the main ways for grape breeding. It is of great significance for wine grape selection and promotion to carry out clonal line selection and evaluation on the original good wine grape varieties. The paper aims to take advantage of the merits of‘Cabernet Sauvignon’, ‘Merlot’and‘Cabernet Franc’clonal lines, and provide the basis for screening out the clonal line with excellent aromas of berries and wines.【Methods】The mature berries of 5 clonal lines of‘Cabernet Sau- vignon’(685, 169, 170, 338, 191), 3 clonal lines of‘Merlot’(181, 343, 348) and 3 clonal lines of‘Cabernet Franc’were used as materials, and the volatile aroma components in berries and wines were analyzed. The berries were collected from grape vines grown in the vineyards of Pomology Institute, Shanxi Academy of Agricultural Science in Taigu, Shanxi province during September to October in 2016. The samples were frozen using liquid nitrogen and stored in an ultra-low temperature freezer. The wines were made in 2016. The volatile aroma components of the berries and wines were analyzed using headspace solid phase micro- extraction (HS-SPME) and gas chromatography-mass spectrometry (GC- MS) combined with automated mass spectral deconvolution and identification system (AMDIS).【Re-sults】The types and contents of volatile aromas in berries and wines of various varieties were different, and there were differences among the different lines of the same variety. The types of aroma compo-nents in the berries and wines of 11 wine grape varieties were 64-99 and 105-121, respectively, and the corresponding components of the berry and wine were 60-88. These aroma components were divided in- to seven categories including medium- chain fatty acids, alcohol esters, alcohols, acetic esters, alde-hydes, monoterpenes and norisoprenoids, ect. Except for the alcohols of‘Cabernet Sauvignon’685 and aldehydes of 191, the concentration of each type aroma components of wine in other lines was higher than that of berry. Among the seven types of aroma compounds, medium-chain fatty acids were mostly abundant, followed by alcohols in the berries, and then by alcohols or ethyl esters in the wines. There were respectively 5-8 and 17-21 types of volatile aroma components in berries and wines exceeding the threshold, and the common ones in 11 wine grape varieties were 5 and 15, respectively. However, the odor activity value (OAV value) of the same aroma component of different varieties or different clonal lines of the same variety was different, which led to differences in their aroma characteristics. Among the medium-chain fatty acids, only hexanoic, octanoic and isovaleric acids in wines exceeded the aroma threshold. The content of alcohol esters in berries of‘Cabernet Sauvignon’191 was highest, while only ethyl caprylate in berries of‘Cabernet Sauvignon’191 exceeded the threshold, which gave the berry banana, pear and flower aroma; in wines, there were six types of esters that exceeded the threshold in- cluding ethyl caproate, ethyl caprylate, ethyl butyrate, ethyl acetate, isoamyl acetate, and ethyl lactate, which gave the wine a fruity, floral, creamy and fatty taste. The monoterpenes and norisoprenoids im-parted floral aromas to berries and wines, and β-damascone, β-ionone and geraniol in the berries of 11 wine grape lines exceeded the threshold, while only β-damascone and geraniol in wines exceeded the threshold. The phenylacetaldehyde and decanal exceeded the threshold, which gave the berry floral, sweet, and grassy notes, respectively. The OAV values of phenylacetaldehyde and β-damascone in the berries of‘Cabernet Sauvignon’685, 169 and‘Merlot’348 were higher than other clonal lines, which were consistent with the OAV values of floral and sweet aroma in the berries; the OAV value of me- thoxy-3-isobutylpyrazine (IBMP) in Cabernet Sauvignon 170 was significantly higher than 191, which was consistent with its highest OAV value of plant flavor, and the highest OAV value of TDN was con- sistent with its highest OAV value of chemical flavor. In berries of‘Cabernet Franc’c214, the OAV val- ue of IBMP were higher than that of 327, 409, which gave itself highest plant flavor OAV; and the trend of OAV value of phenylacetaldehyde, β-damastone in 3 clonal lines was consistent with that of caramel flavor and floral aroma. Compared with other clonal lines, the higher ethyl caproate, ethyl caprylate, iso- amyl acetate, phenylacetaldehyde and β-damassone in‘Cabernet Sauvignon’170 and 338 wines gave the wine a higher fruit taste and floral aroma; the higher ethyl caprylate, ethyl caproate and ethyl butyr- ate in the wine of‘Merlot’181 gave the wine a higher fruity and floral aroma; in the Cabernet Franc c214, the OAV values of ethyl caproate, ethyl butyrate, and isoamyl acetate were the highest, which was consistent with the highest OAV value of the fruit flavor of the wine. Higher OAV values of IBMP and decanal in 327 gave the wine a higher plant flavor than c214.【Conclusion】According to the aroma char- acteristics of the berry,‘Cabernet Sauvignon’685 and 169,‘Merlot’348 and‘Cabernet Franc’327 were better, and‘Cabernet Sauvignon’338, 170‘Merlot’181 and‘Cabernet Franc’409 were better according to the aroma characteristics of wine. According to its aroma characteristics and market needs, brewing process can be improved.