Bowen Amy J, Reynolds Andrew G
Cool Climate Oenology and Viticulture Institute (CCOVI), Brock University, St. Catharines, ON L2S 3A1, Canada.
Cool Climate Oenology and Viticulture Institute (CCOVI), Brock University, St. Catharines, ON L2S 3A1, Canada.
Food Res Int. 2015 Oct;76(Pt 3):550-560. doi: 10.1016/j.foodres.2015.06.042. Epub 2015 Jul 13.
Icewine is a dessert wine of substantial commercial value to the Canadian wine industry. Many grapegrowers crop icewine-designated vines at levels double those for table wines; therefore, the experimental objective was to ascertain whether reducing crop level might impact icewine chemical and aroma compound profiles. Three treatments [control (fully-cropped); cluster thin at fruit set to one (basal) cluster per shoot (TFS); cluster thin at veraison (TV)] were evaluated in randomized block experiments for Riesling and Vidal over two seasons (2003-04; 2004-05). Treatments differed in must pH and titratable acidity (both years) and although wines differed for most standard chemical variables, no clear trends existed. Vidal icewines had the highest aroma compound concentrations in the control and TV (2003) and in TFS (2004). Most Vidal aroma compounds differed with crop level: 17/24 (2003) and 23/24 (2004). Vidal odor activity values (OAVs) were highest for: β-damascenone, ethyl octanoate, cis-rose oxide, 1-octen-3-ol, ethyl hexanoate, isoamyl acetate (2003); β-damascenone, 1-octen-3-ol, ethyl octanoate, cis-rose oxide, and ethyl hexanoate (2004). Principal component analysis (PCA) found β-damascenone, ethyl 2- and 3-methylbutyrate, ethyl isobutyrate, ethyl butyrate and 1-heptanol correlated and associated with the control (2003), but most compounds were positively loaded on PC1 and associated with replicate, not crop level (2004). All Riesling aroma compounds differed with crop level (2003) and 22/23 (2004). Both years, most aroma compounds were highest in TV and lowest in TFS wines. Riesling OAVs were highest for: β-damascenone, ethyl octanoate, and ethyl hexanoate (2003, 2004); cis-rose oxide was highly odor potent (2004). PCA of Riesling showed most compounds loaded on PC1 and associated with TV wines (2003). Freeze/thaw events in November/December appeared more important in aroma compound development than adjustment of crop level, and it is therefore concluded that reduction of crop level in Vidal and Riesling vines would not substantially impact icewine aroma composition.
冰酒是一种对加拿大葡萄酒产业具有重大商业价值的甜型葡萄酒。许多葡萄种植者将用于酿造冰酒的葡萄藤的产量控制在餐桌葡萄酒产量的两倍；因此，实验目的是确定降低产量水平是否会影响冰酒的化学和香气成分特征。在两个生长季（2003 - 2004年；2004 - 2005年）对雷司令和维代尔进行随机区组试验，评估了三种处理方式[对照（全产量）；在坐果期疏花至每新梢留一个（基部）果穗（TFS）；在转色期疏花（TV）]。处理方式在葡萄汁的pH值和可滴定酸度方面存在差异（两年均如此），尽管葡萄酒在大多数标准化学变量上有所不同，但没有明显的趋势。维代尔冰酒在对照和TV处理（2003年）以及TFS处理（2004年）中香气成分浓度最高。大多数维代尔的香气成分随产量水平而不同：17/24（2003年）和23/24（2004年）。维代尔的气味活性值（OAVs）在以下成分中最高：β - 大马酮、辛酸乙酯、顺式玫瑰醚、1 - 辛烯 - 3 - 醇、己酸乙酯、乙酸异戊酯（2003年）；β - 大马酮、1 - 辛烯 - 3 - 醇、辛酸乙酯、顺式玫瑰醚和己酸乙酯（2004年）。主成分分析（PCA）发现β - 大马酮、2 - 甲基丁酸乙酯、3 - 甲基丁酸乙酯、异丁酸乙酯、丁酸乙酯和1 - 庚醇与对照相关（2003年），但大多数化合物在PC1上呈正负载，且与重复相关，而非产量水平（2004年）。所有雷司令的香气成分随产量水平而不同（2003年）以及22/23（2004年）。两年中，大多数香气成分在TV处理的葡萄酒中最高，在TFS处理的葡萄酒中最低。雷司令的OAVs在以下成分中最高：β - 大马酮、辛酸乙酯和己酸乙酯（2003年、2004年）；顺式玫瑰醚气味活性很高（2004年）。雷司令的PCA分析表明，大多数化合物负载在PC1上，且与TV处理的葡萄酒相关（2003年）。11月/12月的冻融事件在香气成分形成中似乎比产量水平的调整更为重要，因此得出结论，降低维代尔和雷司令葡萄藤的产量水平不会对冰酒的香气成分产生实质性影响。
