葡萄酒中单宁涩感评价及结构分析研究进展

单宁是红葡萄酒中的重要成分,对红葡萄酒的口感、颜色、稳定性等都有着重要的影响。该文介绍了单宁的涩感评价方法（感官评价、蛋白质沉淀法、电子舌）及结构分析方法（色谱技术、核磁共振技术、质谱技术、基质辅助激光解吸附技术）的研究进展,并提出了今后的研究方向。     

红葡萄酒涩感研究进展

涩感是影响红葡萄酒感官质量及内在品质的关键因素。文章参考国内外研究结果,对比分析了红葡萄酒中的涩感物质、涩感产生机理、涩感强度及质量的影响因素、涩感的评价方法,为改善红葡萄酒质量提供参考。红葡萄酒中的涩感物质包括缩合单宁、水解单宁以及有机酸,涩感是由涩感物质和口腔作用引起的一种干燥的、粗糙的、褶皱的,收敛性的触觉,涩感的强度及质量主要取决于单宁的浓度、聚合度、结构特点,此外还受葡萄品种、产区、酿酒方式影响,涩感的评价方法主要有感官评价、化学分析这2大类,这2种方法往往结合使用以获取最佳分析结果。此外,合理选择葡萄原料及酿造方式也是提升红葡萄酒质量的有效方法。     

黄酒蛋白质沉淀

高分子蛋白质是引起黄酒沉淀的主要因素,其与单宁聚合物引起黄酒冷浑浊、沉淀。绍兴黄酒蛋白质的含量为0．80％;酒脚中的蛋白质含量为50．20％。黄酒蛋白质的沉淀机理主要是由蛋白质的变性团聚,产生分子量大于10000的蛋白质分子,分子量在10000～5000的蛋白质分子易使黄酒形成沉淀;酒体中的多酚（单宁）、金属离子（如铁）、乙醇也会引起蛋白质沉淀。（孙悟）     

桃红葡萄酒沉淀原因的分析

对桃红葡萄酒装瓶后出现的沉淀进行了检验，观察，分析，结果表明，造成沉淀的原因主要是单宁，色素，蛋白质及钙盐。最后提出了工艺改进意见。     

提高红葡萄酒稳定性研究

提高葡萄酒，特别是受色素物质影响的红葡萄酒的稳定性，延长其货架寿命，是每个葡萄酒厂孜孜以求的．然而在生产过程中并不尽人意，有的产品稳定性差，还没到顾客手中就出现失光，及至浑浊沉淀，尤其装瓶超过两年的红葡萄酒更易产生这种现象．葡萄酒稳定性变差有如下诸因素：酒中空气中氧的氧化；酒中蛋白质受温度影响而凝聚；铁与铜等金属的破败；酒石的结晶析出；微生物污染败坏；单宁色素沉淀等．因此，要提高稳定性，必需控制好每一个生产环节。现在通行的红葡萄酒生产工艺如下：酸发酵一贮酒（倒桶）一调配对杀菌一澄清对冷冻一检验对…     

胶原与多酚的新反应研究成果（一）——新鞣制工艺中的黄酮类反应

单宁的收敛性阻碍了植鞣工艺，影响着植物鞣剂在现代工业中的发展。来源于自然资源如绿茶还是从单宁降解得到的非单宁的鞣剂，都会避免因植物多酚的高反应活性而导致裸皮渗透困难的问题。鞣质和非鞣质都可以与醛鞣剂进行结合鞣制，赋予胶原高耐湿热稳定性。带有苯三酚B环的原翠雀定和原刺槐定多酚在文中颇受关注。同时，非鞣质的使用提供了一种用于现代有机鞣制着实有效的途径。     

啤酒中蛋白质的分析及与酿造单宁的作用

[概述]酿造单宁最主要的作用是与蛋白质的作用,因此研究啤酒中的蛋白质成分及研究单宁与何种蛋白结合具有重要的意义。我们从两方面对这一问题进行了初步研究:1、通过氨基酸分析,考察单宁沉淀的蛋白质在组成上的特点。2、通过电泳分析,研究啤酒中蛋白质的分子量分布,同时对加单宁和不加单宁的啤酒典型样品进行分析,考察单宁沉淀的蛋白质在分子量范围上的特点。     

葡萄酒缩合单宁测定方法的比较研究

目的：对比葡萄酒中测定缩合单宁的甲基纤维素沉淀法(MCP法)和蛋白质沉淀法(A-H法),以寻找一种快速准确的测定方法。方法：采用两种方法测定不同类型、产地、品种葡萄酒的缩合单宁,考察其测定值和变异系数;采用液相色谱-质谱联用法(HPLC-MS法)测定缩合单宁含量,采用吸光度法(A280)测定总酚含量,并与上述两种方法的结果对照。结果：(1)MCP法和A-H法均只适用于红葡萄酒缩合单宁测定,MCP法精度略高但差异不显著。(2)MCP法测定值平均为A-H法的9.13倍,但二者存在较好的线性关系(R2=0.6029)。MCP法与HPLC-MS法线性关系良好(R2=0.7733),A-H法较差(R2=0.4843)。(3)MCP法与总酚存在良好的线性关系(R2=0.9095),A-H法与总酚无显著线性关系(R2=0.2872)。结论：两种方法均能反映红葡萄酒缩合单宁含量,但MCP法与HPLC-MS法、总酚具有更高的一致性,如采用A280测定总酚,应采用MCP法测定缩合单宁。     

适宜‘法国野’葡萄的葡萄酒生产类型探究

为挖掘云南地方酿酒葡萄品种‘法国野’的酿酒潜力,筛选适合该品种的葡萄酒生产类型和基本工艺。采用4种工艺酿制2个类型葡萄酒:浸渍发酵法(maceration-fermentation,MF)酿制干红葡萄酒、冷浸渍+放血法(cold pre-fermentation maceration&saignée,CMS)酿制桃红葡萄酒、冷浸渍+放血+浸渍发酵法(cold pre-fermentation maceration,saignée and maceration-fermentation,CMS-MF)酿制干红葡萄酒,直接压榨法(direct press,DP)酿制桃红葡萄酒,其中2款干红葡萄酒均进行苹果酸-乳酸发酵(malolactic fermentation,MLF)。陈酿3个月后,对4款葡萄酒进行理化指标分析和感官评价。结果表明:与DP和MF相比,CMS和CMS-MF可分别显著提高桃红和干红葡萄酒的单宁、花色苷、总浸出物含量及色度;且CMS和DP桃红葡萄酒的香气、口感和总评得分均显著高于MF和CMS-MF干红葡萄酒,但同类型葡萄酒间的感官质量并无显著差异(P<0.05)。相关性分析表明,感官评价总评得分与酒精度和可滴定酸含量呈显著正相关,与花色苷、单宁和总浸出物含量呈显著或极显著负相关,这证明了MF和MLF工艺均不利于改善‘法国野’葡萄酒的感官质量。此外,与CMS相比,DP可显著提高葡萄汁的还原糖含量和最终葡萄酒的酒精度,并显著降低对单宁的浸提,且保持相当的感官质量。因此,酿酒葡萄‘法国野’更适合于酿造桃红葡萄酒,可将DP作为首选工艺,因其在确保葡萄酒感官质量的同时,又可减少工序、节约成本。     

红葡萄酒颜色研究

颜色对于红葡萄酒的感官质量起着重要作用,红葡萄酒中的呈色物质主要是花色苷,花色苷类物质的浓度与组成决定葡萄酒颜色的深度与稳定性.红葡萄酒的颜色受多方面因素影响,如酿造红葡萄酒的原料质量、栽培措施、发酵条件、稳定工艺、酵母菌、添加物(有机酸、色素酶、单宁等)及陈酿与贮存等.从多方面对有关红葡萄酒颜色的研究进行了阐述,并对我国红葡萄酒生产中存在的一些问题进行了讨论.     

Comparison of analytical methods for the determination of condensed tannins in grape skin

Background and Aims: Condensed tannins extracted from grapes are an important organoleptic component of wine. Assessing tannin level in grapes requires an effective analytical method. This study compared the efficacy of three analytical methods. Methods and Results: Condensed tannin levels were measured in 38 grape skin samples by protein and methylcellulose precipitation and by high‐performance liquid chromatography (HPLC)‐phloroglucinolysis. Total phenolics were determined by absorbance at 280 nm. Tannin levels by protein and methylcellulose precipitation were of similar magnitude, while levels determined by HPLC‐phloroglucinolysis were generally higher. No correlation was found between the level of phenolics and tannins by any of the methods employed. Neither was there a correlation between tannin levels determined by HPLC‐phloroglucinolysis and by precipitation, although previously a strong correlation had been reported between protein precipitation and HPLC‐phloroglucinolysis in wine. Conclusions: The ratio of tannin to non‐tannin phenolics is highly variable between cultivars. Each analytical method measures a different fraction of the tannin extracted from grape skin. Significance of the Study: The disparity between analytical methods requires that method selection reflect the decision‐making that will utilise the information produced. For example, protein precipitation of tannins by bovine serum albumin (BSA) has been correlated with perceived astringency; consequently this may be the best indicator of potential mouthfeel.     

红葡萄酒呈涩物质的化学分析

利用明胶指数法、卵清蛋白沉淀法、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、福林-肖卡法、蛋白沉淀法测定24 个红葡萄酒酒样中呈涩物质的含量,并与感官评价的涩感强度进行对比分析。结果表明,蛋白沉淀测定单宁的方法与感官评价结果的涩感强度相关性最好,且该方法操作简单,适合在酒厂进行推广。     

Comparison of analytical methods for measuring proanthocyanidins in wines and their relationship with perceived astringency

The concentration of proanthocyanidins from twenty red wines from cv. Cabernet Sauvignon, five rosé wines from cv. Cabernet Sauvignon and five white wines from cv. Sauvignon Blanc was quantified using four analytical methodologies, and their relationship with the perceived astringency was investigated. Proanthocyanidin concentrations were determined by a methylcellulose precipitation assay, a protein precipitation assay and two colourimetric methods (Bate‐Smith and vanillin assay). The four methodologies showed high repeatability but differed widely in proanthocyanidin concentrations. The methylcellulose and protein precipitation assays could not quantify proanthocyanidins in rosé and white wines. The protein precipitation assay gave the lowest concentration of proanthocyanidins in all of the red wines. The methylcellulose precipitation assay (r = 0.7725; r² = 0.59) and the protein precipitation assay (r = 0.6828; r² = 0.47) showed a strong correlation with the perceived astringency compared with the colourimetric methods. The strong correlation of the methylcellulose precipitation method with the perceived astringency could be a useful tool to estimate red wine astringency.     

Influence of Visual Masking Technique on the Assessment of 2 Red Wines by Trained and Consumer Assessors

ABSTRACT:  During sensory evaluation assessments, visual masking techniques are frequently employed to disguise color differences between samples and minimize perceptual bias. Particularly in wine, the impact of these masking techniques on panelist evaluations has not been well studied. The objective of this study was to study the influence of visual masking techniques on the aroma and flavor assessment of 2 red wines and observe the impact of these techniques on trained and consumer sensory panels. Specific masking techniques included (1) blue wine glass/white illumination; (2) clear glass/red illumination; and (3) clear glass/white illumination. Ten panelists were trained to recognize 7 aroma and flavor attributes, while consumer panelists ( n = 80) evaluated attributes and liking. For the trained panel, the visual masking technique affected only perceived spicy flavor of Syrah ( P ≤ 0.05), with the clear glass/red illumination resulting in more intense spicy flavor compared to the other 2 conditions. Principal components analysis showed that for the 2 red wines evaluated by the trained panel, red illumination resulted in higher spicy attributes and perceived astringency while wines served in blue wine glasses were higher in perceived astringency. For the consumer panel, red illumination resulted in wines higher in perceived astringency and blue wine glasses resulted in wines higher in perceived flavor liking. These results indicated that the visual masking techniques may influence both trained and consumer panel evaluation of aroma and flavor attributes of red wine. However, beyond red wine, this study makes the larger point that the choice of masking technique does impact sensory evaluations.     

Analysis of grape and wine tannins: Methods, applications and challenges

Tannins are polyphenolic secondary metabolites, which can be found in many higher plants and are identified by their ability to complex with and precipitate proteins. This key property is believed to be responsible for the mouth‐feel and astringency caused by wine tannins. The analysis of tannins is of interest to practitioners in a diverse range of fields, including chemistry, pharmacology, food science, animal nutrition, ecology and plant physiology. There is a desire within the Australian wine industry to exploit objective tannin measures to complement human sensory assessment for style and quality specifications. This review, therefore, concentrates on grape‐derived condensed tannins, also known as proanthocyanidins, and wine tannins formed from grape tannins. We summarise recent advances with the development of analytical methods for the quantification of tannins, review techniques for the structural characterisation of tannin molecules and emphasise the need to refine these techniques.