不同浸渍工艺对贵人香干白葡萄酒香气品质的影响

为提升贵人香干白葡萄酒的香气品质,以澄清汁发酵工艺(CQ)为对照,利用顶空固相微萃取结合气相色谱质谱联用技术(HS-SPME/GC-MS)检测浸渍工艺(JZ)和浸渍澄清工艺(JC)处理发酵酒样中的挥发性香气化合物。结果表明,浸渍处理可以明显增加葡萄酒中香气物质的含量。与CQ相比,JZ和JC对发酵酒样中品种香气物质的含量影响显著(P<0.05),萜烯类化合物含量分别增加1.86、1.01倍,且JC酒样中醇类、酯类香气物质含量最高,分别为4 799.38 μg·L^-1和5 013.28 μg·L^-1。主成分分析结合感官评价结果表明,JZ和JC酒样的花香特征相似,且JC酒样的热带水果香气以及醇香特征更为明显;与CQ相比,JC发酵酒样香气优雅、纯正,口感平衡。综合分析,浸渍澄清工艺(JC)可有效提升甘肃河西产区贵人香干白葡萄酒的香气品质。本研究结果可为干白葡萄酒增香酿造提供技术支持。     

不同酵母在蛇龙珠干红葡萄酒酿造中的应用

该试验在规模化生产条件下对不同酵母的使用效果进行了研究,结果表明在烟台地区,D254酵母比较适合于蛇龙珠干红的发酵,旋转发酵罐发酵的葡萄酒中单宁、总酚含量远高于立式罐发酵的葡萄酒,更为适合陈酿型葡萄酒的酿造.     

优选非酿酒酵母胞外酶增香酿造干白葡萄酒效果

为了研究非酿酒酵母胞外酶促进葡萄酒发酵产香的效果,该文在爱格丽葡萄汁酒精发酵12 h后,分别添加优选胶红酵母(Rhodotorula mucilaginosa,RM)胞外酶液,优选发酵毕赤酵母(Pichia fermentans,PF)胞外酶液和商业糖苷酶制剂(almondβ-glucosidase,AG)(10 mU/mL),以不添加酶制剂的酿酒酵母纯发酵为对照,发酵过程中每24 h取样,采用HS-SPME-GC/MS(headspace solid-phase microextraction-gas chromatography/mass spectrometry)监测挥发性成分的生成变化。葡萄酒含糖量低于2 g/L时终止发酵,低温满罐密封储存,次年4月,进行葡萄酒香气仪器和感官量化分析。胞外酶液共测得6种风味酶活性,其中RM酶液中的β-D-葡萄糖苷酶、α-L-鼠李糖苷酶、β-D-木糖苷酶活性均显著(P<0.05)高于PF中的,而α-L-阿拉伯糖苷酶和酯酶在PF酶液中活性更高(P<0.05)。发酵过程中,胞外酶处理显著促进了(P<0.05)品种香气和发酵香气物质的生成,其中RM酶液显著提高了萜烯类物质和苯乙基类化合物含量,其作用效果分别比商业酶处理高41.7%和31.8%,PF酶液显著促进了发酵香气化合物的生成,尤其是脂肪酸乙酯含量约为对照的2倍。酒样感官分析结果显示,两株酵母的胞外酶处理表现出各自增香酿造的优势,其中RM酶液促进温带酸果类香气的效果突出,PF酶液显著提升了柑橘类香气。研究结果为酵母风味酶应用于葡萄酒的增香酿造提供了理论和实践指导。     

混菌发酵对美乐低醇桃红葡萄酒香气的影响

为提高美乐低醇桃红葡萄酒中挥发性香气化合物的含量,选用2株非酿酒酵母Mstschnikowia pulcherrima和Pure Torulaspora delbrueckii分别与酿酒酵母混菌发酵,采用顶空固相微萃取和气相色谱-质谱联用技术测定不同发酵阶段葡萄酒样的香气化合物。结果表明,与PL-Sc相比,Met-Sc组中挥发性香气化合物的含量较高,尤其是酯类、高级醇和萜烯类。通过微酿试验验证了混菌发酵后Met-Sc组的香气品质,此外该组酒样的花香、果香和香气浓郁度评分明显高于对照组,且具有强烈花香、果香的同时其酒体香气复杂性和层次感有所增强。综合分析,Mstschnikowia pulcherrima-S.cerevisia(ES488)混菌发酵可明显提高了美乐低醇桃红葡萄酒香气品质,这为生产高品质低醇葡萄酒提供了技术支持。     

不同酿造工艺对毛葡萄酒香气的影响

为探索酿造工艺对毛葡萄酒风味的影响，利用GC/MS法对秦巴山区野生毛葡萄在两种工艺条件下酿造的葡萄酒的香气成分进行了研究。结果表明：用传统工艺及CO₂浸渍工艺酿造的毛葡萄酒醇类相对含量最高，其中以苯乙醇、戊醇含量最高。在酯类、酮类、酚类方面，两种工艺酿造的原酒比陈酿6个月的酒种类少，相对含量低；而对于其他香气成分，则是原酒高于陈酿6个月的酒。说明一定时间的陈酿对于毛葡萄酒的香气质量有所提高。通过对两种工艺的综合比较发现，传统工艺酿造的原酒香气质量优于CO₂浸渍工艺酿造原酒；但经过6个月的陈酿后，CO₂浸渍工艺酿造酒香气质量却高于传统工艺的酿造酒。     

西北地区干红葡萄酒产地与酒龄的理化判别方法

西北地区具有独特的风土条件，适宜酿酒葡萄的种植，已形成"大产区大品牌"的产业规划。但西北地区葡萄酒的地域风格尚不明晰，导致产业的规范性不足，可持续发展存在隐患。该研究分析西北地区干红葡萄酒的23项重要的色泽-味感理化指标，旨在开发一种基于机器学习技术的葡萄酒判别方法，实现西北地区干红葡萄酒产地和酒龄的精准判别。首先，以西北地区200款干红葡萄酒为研究对象，通过理化试验测定了总酚、总花色苷、滴定酸等23项色泽-味感理化指标；然后，采用Pearson相关系数分析了西北产区葡萄酒质量特征的一致性，并耦合随机森林（Random Forest, RF）分析理化指标对干红葡萄酒产地和酒龄表征的贡献度；最后，基于人工神经网络（Artificial Neural Networks, ANN）构建了西北地区干红葡萄酒产地和酒龄的精准判别模型。结果表明，色泽相关指标的模型贡献率合计31%，花色苷相关指标的模型贡献率合计26%，酚类物质相关指标的模型贡献率合计21.1%。模型对宁夏产区酒样判别的灵敏度（Sensitivity, SEN）为98.72%，准确率（Accuracy, CCR）98.72%；对新疆产区酒样判别的SEN为95.45%，CCR为100%；对甘肃产区酒样判别的SEN为100%，CCR为95.45%。该方法可以实现西北产区干红葡萄酒产地和酒龄的精准判别，可为中国西北地区优质葡萄酒的生产和产品的市场监管提供科学依据。     

戴尔有孢圆酵母调控晚采小芒森葡萄酒乙酸和香气

为降低甜型葡萄酒中的挥发酸,进一步增加其香气复杂度,该研究利用本土戴尔有孢圆酵母R12与酿酒酵母NX11424同时接种和顺序接种发酵,研究其对贺兰山东麓产区晚采小芒森葡萄酒乙酸及香气成分的调控。与酿酒酵母单菌发酵相比,本土戴尔有孢圆酵母与酿酒酵母按照5:1、20:1、50:1的不同菌体数量比例同时接种和间隔5d顺序接种发酵,均可以显著降低晚采小芒森葡萄酒的乙酸含量,其乙酸产率分别降低19.1%、21.2%、38.2%和48.9%。此外,按20:1比例同时接种发酵,可显著提高晚采小芒森葡萄酒中萜烯类和降异戊二烯类等品种香气物质含量,和乙酸异戊酯、丁酸乙酯及苯乙醇等发酵香气物质的含量。该研究表明合理的酿酒酵母接种发酵能有效降低高糖原料酿造葡萄酒挥发酸含量,为贺兰山东麓产区葡萄酒新产品的开发提供了的技术参考。     

加热处理对蜂蜜酒香气物质的影响

为研究适合蜂蜜酒发酵的优良工艺条件,以2批荆条蜜(白色和浅琥珀色)为原料,在酒精发酵前对发酵醪液进行加热处理,以不加热处理的样品为对照,采用酿酒酵母FX10进行发酵,发酵结束后测定蜂蜜酒的各项理化指标及挥发性化合物的含量。结果表明,供试酒样中共检测出77种挥发性物质,其中酯类39种、醇类20种、酸类8种、萜烯类4种、羰基化合物6种。加热处理可以显著增加蜂蜜酒中香气物质的种类和含量,含量较高的香气物质有乙酸乙酯、乙酸苯乙酯、乙酸异戊酯、己酸乙酯、辛酸乙酯、癸酸乙酯、月桂酸乙酯、9-十六碳烯酸乙酯、异戊醇、β-苯乙醇、辛酸和癸酸。对蜂蜜酒中香气物质进行主成分分析,发现加热处理的酒样中酯类物质对酒香贡献较大;对照酒样中酯类物质对酒香贡献较小,而醇类物质是其主要挥发性成分。本研究结果为蜂蜜酒的生产提供了一定的理论依据。     

基于近红外光谱技术的葡萄酒原产地辨识方法

该文以鉴别葡萄酒原产地为目的,利用快速无损的近红外光谱分析技术,对47份来自昌黎、沙城和法国波尔多（Bordeaux）的红葡萄酒样品进行逐步回归分析选取光谱区域,再进行主成分分析和聚类识别,建立了判别葡萄酒原产地的预测模型。试验结果表明：昌黎、沙城和波尔多产地的葡萄酒产地鉴别的光谱区域为1 400～1 550 nm 和2 000～ 2 300 nm;3个产地的葡萄酒在主成分特征空间中基本为独立分布,其中波尔多酒样和国内酒样间距离最远,国内昌黎和沙城酒样间有小部分交叉;利用9个独立预测集样本对由38个训练集样品所建立的预测模型进行验证,产地的正确识别率达到了88.9%。因此,应用近红外光谱分析技术可准确、快速地辨别葡萄酒的产地。     

6种食用芳香植物挥发性成分的GC-MS/GC-O分析

挥发性成分是芳香植物具有多样风味及香气性能的物质基础。为研究常见可食用芳香植物的挥发性成分及其风味特性的异同,构建特色芳香植物风味数据库,利用气相色谱-质谱联用技术分析经顶空法萃取的6种食用芳香植物(薄荷、藿香、罗勒、丁香罗勒、香薷及密花香薷)的挥发性成分,经气相嗅辨仪对其挥发性成分进行香气描述分析,对比研究6种芳香植物挥发性成分的异同及香气性能的差异。结果表明:6种芳香植物香气主要由萜烯类、醇类、酮类、醛类成分组成,含有少量的酯类、杂环类及芳香族类化合物,多具有辛辣、刺激、樟脑样香气及清新的柠檬、柑橘风味。薄荷中以具花香和柠檬样香气的香叶醇、香茅醇及柠檬醛、香叶醛含量较多;藿香中以左旋薄荷酮及草蒿脑为主,具木香及大茴香似香气特征;罗勒中丙烯酸酯和芳樟醇是其主体成分,辛辣味突出,花香显;而丁香酚成就了丁香罗勒的主体风味,似丁香花香,具辛辣香气;香薷中以具柠檬样香气的D-柠檬烯、柠檬醛、γ-萜品烯为主,柠檬醛和香叶醛为密花香薷的主体成分,整体偏辛辣,花香透,伴柠檬样清新香气。不同的挥发性成分,以一定的比例及含量组成呈现了芳香植物的特征香气。研究结果可为特色芳香植物的品种选育、香气品质提升及风味性能的研究提供科学数据参考。     

Reconstitution of the flavor signature of Dornfelder red wine on the basis of the natural concentrations of its key aroma and taste compounds

By application of aroma extract dilution analysis (AEDA) on the volatile fraction isolated from a Dornfelder red wine, 31 odor-active compounds were identified by means of HRGC-MS and comparison with reference compounds. A total of 27 odorants, judged with high FD factors by means of AEDA, was quantitated by means of stable isotope dilution assays, and acetaldehyde was determined enzymatically. In addition, 36 taste-active compounds were analyzed by means of HPLC-UV, HPLC-MS/MS, and ion chromatography. The quantitative data obtained for the identified aroma and taste compounds enabled for the first time the reconstruction of the overall flavor of the red wine. Sensory evaluation of both the aroma and taste profiles of the authentic red wine and the recombinate revealed that Dornfelder red wine was closely mimicked. Moreover, it was demonstrated that the high molecular weight fraction of red wine is essential for its astringent taste impression. By comparison of the overall odor of the aroma recombinate in ethanol with that of the total flavor recombinate containing all tastants, it was shown for the first time that the nonvolatile tastants had a strong influence on the intensity of certain aroma qualities.     

Volatile and color composition of young and model-aged Shiraz wines as affected by diammonium phosphate supplementation before alcoholic fermentation

A Shiraz must with low yeast assimilable nitrogen (YAN) was supplemented with two concentrations of diammonium phosphate (DAP) and then fermented with maceration on grape skins. The nonvolatile, volatile, and color composition of the final wines were investigated. Ethanol and residual sugars were not affected by DAP supplementation, while glycerol, SO 2, and residual YAN increased and acetic acid decreased. DAP-supplemented treatments gave rise to higher concentrations of acetates, fatty acids, and fatty acid ethyl esters but lower concentrations of branched-chain fatty acids and their ethyl esters. No major difference between treatments was observed for higher alcohols, monoterpenes, norisoprenoids, and low-molecular-weight sulfur compounds. DAP-supplemented fermentations resulted in wines with higher concentrations of malvidin-3-glucoside, higher color intensity, and altered color tonality. Model aging studies indicated that higher concentrations of esters are still present in wines from the DAP-treated fermentations after aging. DAP supplementation also resulted in increased concentrations of dimethyl sulfide after model aging. It can be concluded that DAP treatment of a low YAN must fermented by maceration on skins can significantly affect wine color, aroma, and flavor.     

Characterization of volatile compounds contributing to naturally occurring fruity fermented flavor in peanuts

Published research has indicated that ethyl 2-methylpropanoate, ethyl 2-methybutanaote, ethyl 3-methylbutanoate, hexanoic acid, butanoic acid, and 3-methylbutanoic acid are responsible for fruity fermented (FF) off-flavor; however, these compounds were identified in samples that were artificially created by curing immature peanuts at a constant high temperature. The objective of this study was to characterize the volatile compounds contributing to naturally occurring FF off-flavor. Volatile compounds of naturally occurring FF and no-FF samples were characterized using solvent-assisted flavor evaporation (SAFE), solid phase microextraction (SPME), gas chromatography-olfactometry (GC-O), and gas chromatography-mass spectrometry (GC-MS). Aroma extract dilution analysis (AEDA) identified 12 potent aroma active compounds, none of which were the previously identified esters, with no consistent differences among the aroma active compounds in no-FF and FF samples. Hexanoic acid alone was identified in the naturally occurring FF sample using the SAFE GC-MS methodology, whereas two of the three previously identified esters were identified in natural and artificially created samples. The same two esters were confirmed by SPME GC-MS in natural and artificially created samples. This study demonstrated the need for caution in the direct application of data from artificially created samples until those compounds are verified in natural samples. However, these results suggest that a laboratory method using SPME-GC techniques could be developed and correlated on an ester concentration versus FF intensity basis to provide an alternative to sensory analysis for detection of FF off-flavor in peanut lots.     

Impact of growing environment on chickasaw blackberry (Rubus L.) aroma evaluated by gas chromatography olfactometry dilution analysis

The aroma extract of Chickasaw blackberry (Rubus L.) was separated with silica gel normal phase chromatography into six fractions. Gas chromatography-olfactometry (GCO) was performed on each fraction to identify aroma active compounds. Aroma extraction dilution analysis (AEDA) was employed to characterize the aroma profile of Chickasaw blackberries from two growing regions of the United States: Oregon and Arkansas. Comparative AEDA analysis showed that the berries grown in the two regions had similar aroma compositions; however, those odorants had various aroma impacts in each region. The compounds with high flavor dilution factors in Oregon's Chickasaw were ethyl butanoate, linalool, methional, trans,cis-2,6-nonadienal, cis-1,5-octadien-3-one, and 2,5-dimethyl-4-hydroxy-3(2H)-furanone, whereas in the Chickasaw grown in Arkansas, they were ethyl butanoate, linalool, methional, ethyl 2-methylbutanoate, beta-damascenone, and geraniol.     

Definitive evidence for the actual contribution of yeast in the transformation of neutral precursors of grape aromas.

Experiments were designed to demonstrate the actual contribution of yeast in the formation of the primary aroma during the vinification of neutral grapes. Ruché was chosen as the model wine to study because of its unique fragrance. A yeast strain specific for Ruché was selected using a new and rapid isolation method for red wines. The results of this study can be summarized as follows: Skins from nonaromatic white or red grapes apparently contain most of the primary aroma compounds that are revealed in the must only after contact with yeast cells under defined conditions. Similar results were obtained with the pulp and seeds fractions; however, the olfactory notes, although well characterized, differed from those obtained with skins alone. Clarification, filtration, and centrifugation of the pulp and seed fractions or sonification of the skins produce different and well-characterized olfaction notes during the contact with yeast. The primary aroma of nonaromatic white and red grapes contained in the skins can be revealed within 24-48 h of yeast contact in a synthetic nutrient medium (SNM). The primary aroma precursors extracted from the skins with methanol, water-saturated butanol, or aqueous buffer at pH 3.2, concentrated and eluted from a C18 resin column, can be transformed to the free form wine aroma markers within 6 h of contact with yeast cells in SNM. By contrast, prolonged maceration of the skins in aqueous alcoholic buffer at pH 3.2 or 1.1, at 50 or 70 degrees C did not release primary odors typical of wine. The individual primary aroma compounds, identified by GC-MS analysis in Ruché wine samples or in Ruché skin-yeast-SNM samples, could not explain the complexity of the typical Ruché wine odor. Only odors common to many wine varieties were identified by GC-olfactometry analysis.     

Characterization of aroma compounds of chinese "Wuliangye" and "Jiannanchun" liquors by aroma extract dilution analysis

Aroma compounds in Chinese "Wuliangye" liquor were identified by gas chromatography-olfactometry (GC-O) after fractionation. A total of 132 odorants were detected by GC-O in Wuliangye liquor on DB-wax and DB-5 columns. Of these, 126 aromas were identified by GC-mass spectrometry (MS). Aroma extract dilution analysis (AEDA) was further employed to identify the most important aroma compounds in "Wuliangye" and "Jiannanchun" liquors. The results showed that esters could be the most important class, especially ethyl esters. Various alcohols, aldehydes, acetals, alkylpyrazines, furan derivatives, lactones, and sulfur-containing and phenolic compounds were also found to be important. On the basis of flavor dilution (FD) values, the most important aroma compounds in Wuliangye and Jiannanchun liquors could be ethyl butanoate, ethyl pentanoate, ethyl hexanoate, ethyl octanoate, butyl hexanoate, ethyl 3-methylbutanoate, hexanoic acid, and 1,1-diethoxy-3-methylbutane (FD > or = 1024). These compounds contributed to fruity, floral, and apple- and pineapple-like aromas with the exception of hexanoic acid, which imparts a sweaty note. Several pyrazines, including 2,5-dimethyl-3-ethylpyrazine, 2-ethyl-6-methylpyrazine, 2,6-dimethylpyrazine, 2,3,5-trimethylpyrazine, and 3,5-dimethyl-2-pentylpyrazine, were identified in these two liquors. Although further quantitative analysis is required, it seems that most of these pyrazine compounds had higher FD values in Wuliangye than in Jiannanchun liquor, thus imparting stronger nutty, baked, and roasted notes in Wuliangye liquor.