| The aroma compounds of the main cultivated varieties and their wines from the Ningxia Helan Mountains's Eastern Region were analyzed by GC-MS . Evolutions during stage of fermentation, racking, bottling, and aging were also studied systematically. The samples of 29 dry red wines and 10 white wines were selected. The aromatic compounds were extracted by solvent extraction and analyzed by GC-MS. Their relative contents were determined by area normalization. The total 380 chemical constituents of volatile compounds were identified and the detection rate was about 90% of the total peak area. In total 141,163,197and 178 kinds aroma were detected from Cabernet Sauvignon, Merlot, Cabernet Gernischt and Chardonnay. The results showed that aromatic compounds from grape varieties and their wines at different stages had different evolutionsIn grapes, 43, 47 and 51 aromatic compounds were found in Cabernet Sauvignon, Merlot, Cabernet Gernischt respectively. There were 81 kinds of aromatic components in Chardonnay. They belonged to olefinic aldehydes, aldehydes, ketones, higher saturated and unsaturated fatty acids, esters, phenols and other chemical groups. The grapes varieties differed widely in the categories and contents of aromatic constituents. As raw materials for dry red and white wine making, the differences in aroma precursors must cause obvious difference in aroma of fermentation and ageing wine. The aromatic compounds and relative contents in grapes and dry red wine of Carbenet Gernischt were analyzed by GC-MS for the first time. Using principal component analysis, cluster analysis and reference to the theoretical genetic laws for aromatic components , the aromatic composition of Cabernet Gernischt was different greatly from Cabernet Sauvignon, Merlot and Chardonnay in cluster maps. During the fermentation of three monovariety dry red wines and one white wine, 95, 99, 105 and 131 aroma components from Cabernet Sauvignon, Merlot, Cabernet Gernischt and Chardonnay were detected by GC-MS respectively. Through fermentation, there were 15, 8, 17 and 8 compounds separately. These indicated that the intermediate products of fermentation changed greatly. The evolution for aroma components was as follow: the relative contents of total ester, total alcohols increased obviously, but organic acids and ketones reduced greatly. Aldehydes transformed acutely once the fermentation began, and disappeared or existed as traces at the end of fermentation; while heterocyclic compounds changed violently in the early stage of fermentation from zero through traces to increasingly higher content, and than degraded totally, but they appeared again in the middle end of fermentation. The compounds containing nitrogen were undetected in the juices but were gradually produced following fermentation. From three monovarietal dry red wines and one dry white wine, 57, 46, 49 and 33 aromatic compounds and relative contents were detected separately in Cabernet Sauvignon, Merlot, Cabernet Gernischt and Chardonnay. There were mainly fatty acids, fatty alcohol, aralkanols, fatty ketones, heterocyclic compounds, ethers and other chemical groups. The higher relative contents and patterns of aromatic compounds were similar but characteristic aroma trace components were very different , which lead to a unique aroma and style for different variety wines.In racking, finished product and storage in bottle of monovariety dry red wines, 61, 59 and 66 aroma components from Carbenet Sauvignon, Merlot and Cabernet Gernischt were detected by GC-MS respectively. 31, 32 and 32 compounds in common existed through out the three processes. It showed that aroma changes greatly and uncoordinated patterns different each variety wine. The evolution in Cabernet Sauvignon was: alcohols changed in content from very high→low→high; organic acids changed in content from lowest→low→lower; esters were very high→high→super high; heterocyclic compounds degraded; ketones produced esters undetected in the early stage and increased gradually in the st...
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