新疆产区酿酒葡萄果实中有机酸的比较分析

以新疆4个小产区赤霞珠葡萄果实及天山北麓产区4种红色酿酒葡萄果实(品丽珠、西拉、小味尔多、马瑟兰)为原料,研究了不同产区、品种间有机酸含量的差异。采用反相高效液相色谱法(RP-HPLC),对赤霞珠果实生长周期4种有机酸(草酸、酒石酸、苹果酸、柠檬酸)变化情况进行分析。结果表明,随着葡萄成熟度增加,赤霞珠果实中有机酸总含量呈现下降趋势,草酸和柠檬酸含量较低,变化不明显;新疆4小产区的赤霞珠葡萄果实中有机酸总含量在3.97~7.96mg/g范围内且存在明显差异(p<0.05),产于天山北麓五家渠产地的赤霞珠有机酸总含量最高达7.96 mg/g,其中草酸、酒石酸、苹果酸分别为0.55 mg/g、4.66 mg/g、2.47 mg/g,产于伊犁河谷67团产地的赤霞珠有机酸总含量最低3.97 mg/g;通过对同一产地不同酿酒葡萄果实有机酸物质进行主成分分析,发现西拉、马瑟兰的酒石酸相对含量较高,赤霞珠的草酸和柠檬酸相对含量较高,品丽珠、小味尔多的苹果酸相对含量比较高。试验表明赤霞珠的有机酸含量在不同产区存在一定差异,同时不同品种在同产地的有机酸积累特性也各不相同,以期为新疆产区酿造中"糖高酸低"的研究提出一些思路。     

Preliminary studies on acidity-astringency interactions in model solutions and wines

Intensity of astringency in model solutions and wines varying in total acid and total phenols was evaluated by paired comparisons by 10 trained judges. Model solutions consisted of tannic (500, 1000, 2000 mg litre^?1) and tartaric (0, 2, 4, 6 g litre^?1) acids dissolved in aqueous solutions of ethanol (120 ml litre^?1) and sucrose (5 g litre^?1). Wine solutions were prepared by addition of citric acid (0, 0.5, 1, 2, 3 g litre^?1 as tartaric acid) to a high phenol-red wine (2645 mg litre^?1 GAE) and a moderate phenol-white wine (800 mg litre^?1 GAE). At all three levels of tannic acid, astringency of model solutions increased significantly (P<0.001) with tartaric acid concentration. Astringency of white wine also increased significantly (P<0.05) with citric acid concentration. A negative linear relation was found between relative astringency and pH at a given tannin level for both model solutions and white wine. As pH was reduced, more phenolic molecules were in the phenol form thereby increasing the likelihood of hydrogen bonding between hydroxyl groups of wine tannins and ketoimide groups of mouth proteins. The preliminary hypothesis that hydrogen bonding is the main reaction involved in the formation of protein-tannin complexes resulting in the sensation of astringency was reinforced.     

Impact of exogenous tannin additions on wine chemistry and wine sensory character

Tannins are an important part of wine quality and are frequently added during winemaking. Tannin additives and their impact on wine are poorly documented. This work sought to characterize a range of enological tannins and their contribution to wine quality. Enological tannins were analysed for protein precipitable tannins and iron reactive phenolics. One tannin product was added to a Merlot wine during barrel ageing, at a range of concentrations from 60 to 300 mg/l. Condensed and hydrolysable tannins were added to Cabernet Sauvignon wine post-pressing at a recommended and excessive rate. Wines were analysed for anthocyanin, small and large polymeric pigment, precipitable tannin, iron reactive phenolics and sensory character. Enological tannins contained 12-48% tannin and recommended additions had little impact on wine tannin. High tannin additions were readily measured in the wines and were discriminated in sensory analysis with lower intensities of most parameters except brown colour, bitterness and earthy character. Recommended addition rates are too low to impact the measured tannin concentration of Merlot and Cabernet Sauvignon wines from Washington (USA). High enological tannin additions had a measureable impact on final wine had a negative impact on sensory character. Tannins are added to wines for a range of reasons and represent one of many input costs in an industry increasingly seeking efficiencies in response to global economic circumstances, over-supply and an ongoing price point squeeze. This research suggests many tannin additions may be unjustified and have limited or negative impacts on quality.     

不同皮渣浸渍发酵时间对葡萄酒中缩合单宁构成及感官品质的影响

为明确不同皮渣浸渍时间对葡萄酒中缩合单宁的影响,以赤霞珠和西拉为材料,进行不同浸渍发酵时间处理,对葡萄皮和葡萄籽以及葡萄酒中缩合单宁的含量、组成、缩合单宁以及相关口感指标等进行了分析。结果表明,不同葡萄品种中缩合单宁的初始含量、聚合度及没食子酰化率都有显著差异（P<0.05）。葡萄皮中缩合单宁的平均聚合度显著高于葡萄籽（P<0.05）,而葡萄皮缩合单宁的没食子酰化率则显著低于葡萄籽缩合单宁（P<0.05）。葡萄皮和葡萄籽中缩合单宁组成的最大差异是葡萄籽缩合单宁中不含有（?）-表棓儿茶素亚单元,而且末端单元主要是由（+）-儿茶素、（?）-表儿茶素和（?）-表儿茶素没食子酸酯组成。皮渣浸渍时间对葡萄酒中缩合单宁的组成及含量都有明显影响。随着浸渍时间的延长,葡萄酒中缩合单宁的总含量呈上升趋势,而平均聚合度则呈下降趋势。不同品种的葡萄酒之间缩合单宁含量也存在显著差异（P<0.05）,这与不同葡萄品种中酚类物质的可浸提率有关。葡萄酒中葡萄皮缩合单宁的占比一直显著高于籽粒缩合单宁的占比（P<0.05）,说明葡萄皮中缩合单宁比葡萄籽缩合单宁更容易浸提到葡萄酒中。相对于苦味和酸味,不同浸渍时间处理对葡萄酒的涩味影响更为显著（P<0.05）,综合考虑酒体的丰满度和口感的平衡,皮渣浸渍时间选择14 d左右更好一些。     

添加葡萄籽单宁对橡木桶陈酿‘赤霞珠’和‘马瑟兰’干红葡萄酒香气的影响

采用气相色谱-质谱联用法和感官分析排序法,研究橡木桶陈酿前添加葡萄籽单宁（200 mg/L）对陈酿12 个月后‘赤霞珠’和‘马瑟兰’干红葡萄酒香气组分和感官特征的影响。结果表明：添加葡萄籽单宁对2 个品种葡萄酒香气的影响各异。葡萄籽单宁添加促进了橡木桶陈酿期间‘赤霞珠’葡萄酒中香草酸、香草醛、香草酸乙酯、糠醛、乙酰呋喃和糠醇等橡木来源香气物质的浸出,而抑制‘马瑟兰’干红葡萄酒中糠醛、乙酰呋喃、糠醇、5-甲基糠醛和5-羟甲基糠醛等橡木来源香气物质的浸出。添加葡萄籽单宁后,‘赤霞珠’葡萄酒的生青味和浆果香降低,烘烤味增强,‘马瑟兰’葡萄酒的生青味和花香略有增强,对陈酿型干红葡萄酒的生产具有重要指导作用。     

三种红色酿酒葡萄品种果实酚类物质比较

为了综合评价酿酒葡萄品种特性,以酿酒葡萄美乐、品丽珠、赤霞珠为研究对象,采用比色法测定果实不同部位酚类物质含量,并对结果进行主成分分析。结果表明,赤霞珠葡萄果皮中总酚、单宁、黄烷醇、花色苷含量分别为28.82 mg/g、23.15 mg/g、41.19 mg/g、9.25 mg/g,均显著高于美乐和品丽珠（P＜0.05）;赤霞珠葡萄种子中总酚、单宁、总类黄酮分别为14.56 mg/g、5.74 mg/g、2.32 mg/g,显著高于品丽珠（P＜0.05）。主成分分析结果表明,赤霞珠葡萄酚类物质在第一主成分和第二主成分综合得分为82.27分,为酚类物质含量丰富的品种。     

Comparative study of aromatic compounds in young red wines from cabernet sauvignon, cabernet franc, and cabernet gernischet varieties in China

ABSTRACT:  The aromatic composition and key odorants of young red wines produced from Cabernet Sauvignon, Cabernet Franc, and Cabernet Gernischet wines were compared and the reasons for the difference in their aromatic compounds were discussed. Forty-three odorants were detected in Cabernet Sauvignon and Cabernet Franc wines compared to 50 in Cabernet Gernischet wine. Quantitatively, acids formed the most abundant group in the aromatic components of the 3 wines, followed by alcohols and esters. Compared to Cabernet Sauvignon and Cabernet Franc wines, the profiles of alcohols and esters for Cabernet Gernischet wine were more diverse. Monoterpenes, namely, 4-terpinenol, citronellol, and nerol, were found solely in Cabernet Gernischet wine. Only 10 compounds, namely, ethyl octanoate, ethyl hexanoate, isoamyl acetate, ethyl butyrate, β-damascenone, ethyl decanoate, isoamyl alcohol, acetic acid, octanoic acid, and phenylethyl acetate, were always present in the 3 wines at concentrations higher than their threshold values. However, ethyl octanoate, ethyl hexanoate, and isoamyl acetate were found to jointly contribute to 97%, 98.9%, and 99% of the global aroma of Cabernet Sauvignon, Cabernet Franc, and Cabernet Gernischet wines, respectively. This result showed that the aroma indistinguishableness of the 3 wines was mainly due to the dominance of the fruity notes exerted by the ethyl esters and, to a lesser extent, to the contribution of varietal aromatic compounds to the global aroma of the wines.     

闪蒸品丽珠干红葡萄酒香气成分的GC/MS分析

采用溶剂萃取法提取闪蒸和传统品丽珠干红葡萄酒中的香气成分,经气相色谱-质谱联机分析,闪蒸干红酒鉴定出30种香气成分,包括16种酯、6种醇、3种萜烯类、4种酸和1种酮,传统干红酒鉴定出26种香气成分,包括14种酯、4种醇、4种萜烯类、2种酮、1种酸和1种醚.与传统品丽珠干红酒相比,闪蒸品丽珠干红酒酯类化合物相对含量提高29.43%,醇类化合物相对含量降低20.99%,葡萄酒香气更加浓郁、复杂、深沉.     

陕西合阳地区酿酒葡萄果实成熟特性研究

该实验研究了合阳地区5个红色和5个白色酿酒葡萄品种在成熟期的可溶性固形物、还原糖、总酸含量和成熟系数变化,分析了成熟葡萄浆果的物理品质、花色苷和单体酚的组成和含量。结果表明,转色期后12 d,各品种葡萄的成熟系数均＞20。成熟葡萄浆果还原糖含量为180～235 g/L,总酸含量＜6 g/L。综合来看,赤霞珠、品丽珠、黑比诺、马瑟兰、爱格丽、小芒森和贵人香适合在合阳地区种植。赤霞珠、品丽珠、黑比诺、马瑟兰和贵人香最适采收期在转色期后24 d左右,爱格丽和小芒森在转色期后44 d左右。马瑟兰的成熟浆果花色苷含量较高,达29.85 mg/g;赤霞珠、马瑟兰和爱格丽成熟浆果单体酚含量较高,分别为0.65 mg/g、0.43 mg/g和0.26 mg/g。研究结果将为陕西合阳地区酿酒葡萄种植与推广提供参考。     

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.     

Fining of Red Wines with Pomace Cell Wall Material: Effect on Wine Phenolic Composition

Fining is a winemaking technique used to remove unwanted wine components that affect clarification, astringency, color, bitterness, and aroma. One of the objectives of fining is often to reduce the wine tannin content due to its effect on wine astringency. Proteinaceous agents are commonly used with this objective, but problems related with their possible allergenic properties or the excessive enrichment of wine with proteins, which may cause stability and turbidity problems, have led to the search for new fining agents. In this way, the cell wall material from processed grape pomace could be a good alternative since it has a high affinity for tannins. In this work, the effect of cell wall material from processed pomace from Monastrell and Cabernet Sauvignon grapes on the reduction of the phenolic content of red wines is studied and the results are compared with those obtained with commercial fining products. Also, the varietal effect due to the different composition of the cell wall material from these two varieties has been evaluated. The concentration and composition of wine anthocyanins and tannins, before and after the fining process, were analyzed by HPLC and their molecular mass distribution by SEC. The results showed that, at laboratory scale, pomace cell walls have a fining effect that exceeds that of most the protein-based fining agents, even when used at their highest recommended doses. The cell wall material significantly reduced the wine phenolic content, the reduction ranging from 48 to 68% for anthocyanins and from 44 to 64% for tannins, although varietal differences exist regarding the cell wall-binding capacity. Monastrell cell walls exhibited the highest capacity and could be used at much lower doses than those used in this study, reducing the formation of lees and the wine adsorbed on them. The results indicate that this material could be an appropriate alternative for protein-based fining agents in red wine and their use would avoid allergen-related effects.     

A new approach to the analysis of tannin concentration using a microelectronic biosensor

Wine tannins are essential to the astringency and color stabilization of red wine through the formation of tannin conjugates. It is important to determine the concentration of tannins during wine aging and fermentation. The aim of this study was to establish a new method that allows for real-time analysis of tannin content in wine and eliminates inconvenient processes, such as calibrations and/or enzyme reactions. The Folin-Ciocalteau spectrophotometry (FCS) was used a positive control and compared it with new microelectrode biosensor cyclic voltammetry (MBCV) method. The new approach was established that not only allows for real-time tannin detection but is also economical and does not require the use of a specific enzyme. The results are reproducible and provide a precise measurement of tannin content.     

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.     

陕西泾阳赤霞珠葡萄冷冻处理酿酒特性研究

葡萄酒中多酚、单宁等功能性成分主要来源于葡萄果皮中,为提高葡萄酒中的酚类物质含量,改善葡萄酒的口感,试验以陕西泾阳赤霞珠葡萄浆果为原料,分别在-20℃和-35℃两种不同温度下进行冷冻处理葡萄浆果并进行小容器酿酒试验,研究了葡萄原料经冷冻处理后葡萄酒中理化指标的差异变化,以及冷冻处理对葡萄酒感官特性的影响。结果表明：赤霞珠葡萄原料经-20℃和-35℃两种不同温度冷冻处理后,葡萄酒中单宁和总酚物质的含量显著增高,且-20℃冷冻处理后含量最高,其中单宁含量为29.54mg/L,总酚含量为129.71mg/L;葡萄原料经-20℃冷冻处理后,葡萄酒的外观、口感和总体评定显著提高。     

Interactions of enological tannins with the protein fraction of saliva and astringency perception are affected by pH

The effects of pH on both tannin-induced astringency and tannin–salivary protein interactions were investigated. A trained sensory panel evaluated astringency perception. Tannin–salivary protein interactions were assessed in vitro by examining the effects of either a condensed enological tannin or an hydrolyzable enological tannin on two physicochemical properties of the protein fraction of saliva, namely, its mode of diffusion on cellulose membranes and its precipitation. Comparative assays mimicking the degree of dilution experienced by saliva during a tasting assay were performed at pH 3.5 and pH 7.0. Results indicated that both enological tannins were perceived as clearly more astringent at pH 3.5 compared with pH 7.0. In addition, the effects of tannins on protein diffusion and protein precipitation were markedly exacerbated at pH 3.5.     

Cabernet sauvignon red wine astringency quality control by tannin characterization and polymerization during storage

Cabernet Sauvignon wine grape variety is an emblematic cultivar of Bordeaux winegrowing region. Twenty-three vintages of Cabernet Sauvignon wines from chateau Mouton Rothschild were studied using chemical and sensory analysis. Total phenolic compounds, total anthocyanins, total tannins, hue, CI (colour intensity), titratable acidity, ethanol level and pH were evaluated. Percentage of galloylation (%G), of prodelphinidins (%P) as well as mean degree of polymerization (mDP) were also determined. Sensory analysis concerning astringency intensity using a 0–7 point scale was performed in parallel. Correlations between bottle wine ageing and mDP and astringency were obtained. Increasing age gave lower scores in astringency intensity (R ² = 0.598, p = 0.000) and inferior mDP values (R ² = 0.851, p = 0.000). In addition, we evidenced that mDP is an analytical parameter for estimating astringency (R ² = 0.556, p = 0.000) in red CS (Cabernet Sauvignon) wine from Pauillac denomination.     

蓝靛果单宁的提取及对酵母发酵能力的影响

为确定酵母菌发酵蓝靛果果汁中的最适单宁含量,采用单因素实验及正交试验优化超声辅助法提取蓝靛果单宁工艺,将此条件下获得的单宁粗提液纯化、浓缩后得到单宁酸样品.将其添加到模拟蓝靛果果汁中,研究不同浓度单宁酸对酵母菌的影响,并验证最适单宁含量对发酵蓝靛果果汁的影响.结果 表明,蓝靛果单宁最优提取条件为:乙醇体积分数50％,料...