【作者】 蔡建；

【导师】 段长青；

【作者基本信息】 中国农业大学 ， 食品生物技术， 2014， 博士

【摘要】 新疆天山北麓是我国主要的葡萄酒产区之一,‘赤霞珠’是该地区主要栽培的酿酒葡萄品种。同我国西部产区大多数‘赤霞珠’葡萄酒的表现类似,该产区的‘赤霞珠’葡萄酒也存在果香不足,香气细腻度、优雅度的缺乏以及颜色稳定性较差的问题。针对这些问题,我们在该地区持续数年地开展了一系列栽培管理调控和酿酒工艺优化实验,试图从葡萄原料种植和葡萄酒酿造两方面对该地区葡萄酒风味品质进行提升和改良。本文主要围绕‘赤霞珠’葡萄原料发酵前处理工艺(冷浸渍与粒选)对葡萄酒香气物质组成的影响进行研究。本文所有研究工作均在工业化规模的葡萄酒酿造基础上进行,首先通过两个发酵季节分别对冷浸渍工艺和粒选工艺进行了实验性应用,并对这两种工艺在发酵过程和后续陈酿过程中对葡萄酒香气物质的影响进行跟踪监测分析。在研究冷浸渍工艺对葡萄酒香气影响的过程中采用了两种类型工业化规模的发酵罐(压帽罐和循环喷淋罐),在研究粒选工艺对香气影响的过程中采用了两种商业化酵母(D254和L2323)分别进行发酵。发酵结束后对不同工艺处理的原酒继续进行12个月的橡木桶陈酿,并跟踪监测陈酿过程中香气物质的变化规律。其中冷浸渍和对照处理原酒分别采用不锈钢罐以及两种纹理(细纹理、中纹理)、两种烘烤度(轻度烘烤、中度烘烤)的法国橡木桶进行陈酿。通过以上内容的研究,我们主要得到以下几个方面的结论：冷浸渍工艺对天山北麓‘赤霞珠’干红葡萄酒果香具有提升作用,并且这种提升作用在橡木桶陈酿12个月过程中依然存在。冷浸渍对果香的提升作用是通过发酵和陈酿阶段一些酯类物质(乙酸异戊酯、乙酸己酯、月桂酸乙酯、9-癸烯酸乙酯、乳酸异戊酯、2-羟基-4-甲基戊酸乙酯等)含量的增加以及一些高级醇(异戊醇、异丁醇等)含量的降低而实现的。冷浸渍工艺的作用效果受到发酵罐类型的影响,采用循环喷淋罐发酵比压帽罐发酵可以更显著地提升一些酯类(乙酸异戊酯、乙酸己酯、癸酸乙酯等)的含量,更有利于冷浸渍效果的发挥。冷浸渍过程中产生的己醇会导致最终葡萄酒中己醇含量显著升高,冷浸渍过程中的压帽操作会对葡萄原料造成较大机械损伤从而进一步加剧己醇的产生。与穗选葡萄酒相比,粒选葡萄酒在发酵结束时的一些酯类物质含量较低从而导致其果香强度相对较弱,但由于苹乳发酵和后期陈酿过程中穗选葡萄酒中这些酯(乙酸异戊酯、癸酸乙酯、辛酸乙酯、月桂酸乙酯)的降解速度较大,橡木桶陈酿12个月后粒选和穗选葡萄酒的果香强度已没有显著性差异。粒选后采用D245酵母发酵比L2323酵母发酵葡萄酒中脂肪酸乙酯(己酸乙酯、辛酸乙酯、癸酸乙酯)和β-紫罗酮含量更高,有利于陈酿后果香的形成。陈酿过程中橡木桶的纹理对癸酸乙酯、月桂酸乙酯和癸酸异戊酯具有显著影响,烘烤度对乙酸异戊酯含量具有显著影响,轻烘烤度、细纹理橡木桶中陈酿更有利于这几种酯含量的保持和果香的形成。更多还原

【Abstract】 The north slope of Tianshan Mountains in Xinjiang is one of the major wine regions in China, and Cabernet Sauvignon is the main wine grape variety in this region. Lack of fruit note and elegance in aroma, poor color stability are main problems for wines from this region as many other Cabernet Sauvignon wines from western China. To improve the overall wine quality in this region, a series of vineyard management and winemaking experiments were conducted by us in recent years. The works showed in this dissertation were parts of the researches, and were focused on the influence of pre-fermentation technologies, such as cold maceration and grape sorting, on wine aroma.All the researches in this dissertation were based on industrial winemaking. The pre-fermentative cold maceration treatment (CM) and grape berry sorting technology were conducted in two successional vintages respectively, and the impacts on wine aroma during fermentation and aging process were studied. Two kinds of industrial scale fermentors, automatic pumping over tank (PO-tank) and automatic pouching down tank (PD-tank), were applied for CM experiment, and two strains of commercial yeasts (L2323, D254) were used for grape sorting experiment. After fermentation, all wines from different treatments were aged in oak barrels for12months, and the aroma compounds were analyzed during the aging process. The CM treated wines (CM-wine) and control wines (Co-wine) were aged both in stainless steel tank and French oak barrels with two toasting degree (light toasted and medium toasted) and grain tightness (tight grain and moderate grain). The results obtained from this study were as follows:The CM treatment had different effect on wine aroma depending on the types of fermentor, more effective for PO-tank than PD-tank. The fruity aroma series were enhanced by the CM treatment in PO-tank fermented wines even after barrel aging. The enhancement of wine aroma by CM treatment was a result of the improvement on some esters (isoamyl acetate, hexyl acetate, ethyl laurate,9-ethyl decenoate, isoamyl lactate, ethyl2-hydroxy-4-methyl pentanoate) and decrease on some fusel alcohols (isobutanol, isopentanol) during fermentation and barrel aging. More hexanol was produced during CM process compared to the Co wines, and punching-down could accelerate this compound in wine.Although the fruity aroma series and some esters were low in berry-selected wines (BS-wine) than cluster-selected wines (CS-wine) at the end of alcoholic fermentation, this difference between BS and CS wines were disappeared at the end of barrel aging due to the rapid degradation of these esters (isoamyl acetate, ethyl decanoate, ethyl octanoate and ethyl laurate). D245was more suitable for making a more fruity wine because of its high production of P-ionone and some esters such as ethyl hexanoate, ethyl octanoate and ethyl decanoate.The toasting degree and grain tightness of oak barrels had some significant impacts on wine odorants derived from fermentation process such as isoamyl acetate, ethyl laurate, ethyl decanoate and isoamyl decanoate. Oak barrels with light toast degree and tight grain were more benefit for the maintenance of these esters and the formation of fruit note during wine aging.更多还原