Effects of pre-fermentation enzyme maceration on extraction and colour stability in Pinot Noir wine

Effects of pre-fermentation enzyme maceration on anthocyanins, phenolics, colour and colour parameters were investigated in Pinot Noir ( Vitis vinifera L.) wines made from musts that were macerated for 12 hours at 20°C with a commercial enzyme preparation, Rohapect VR-C (Rohm, Darmstadt, Germany), with and without additions of SO₂. Anthocyanins and phenolics were determined by spectrophotometric and HPLC methods. Standard triplicate microvinifications were conducted in glass vessels. Extraction of anthocyanins was not increased by enzyme treatment. However, wines produced by enzyme maceration had increased visible colour intensity, colour density and polymeric pigment formation. By the end of fermentation, enzyme-treated wines had more polymeric pigment, and less monomeric anthocyanins than non-enzyme-treated wines. The wines were bottled, stored at 12°C and sampled at three, six, eight and 18 months after bottling. Over 18 months, differences between the treatments were maintained. The promotion of the formation of polymeric pigments in enzyme-treated wines continued after the wines were bottled, and the greater content of polymeric pigment led to greater colour density in the enzyme-treated wines. The promotion of polymeric pigment formation in wines by macerating enzyme treatment of the must may be due to the breakdown of protective polysaccharide-protein colloids by hemicellulase and protease activities in the enzyme preparation.     

黑皮诺冷浸渍工艺的应用效果研究

以黑皮诺（Pinot Noir）酿酒葡萄为原料,采用常温浸渍和冷浸渍两种方式处理原料后进行正常的酒精发酵,发酵结束后测定并分析两组葡萄酒的理化和感官指标,以此为依据来判断冷浸渍工艺与干红葡萄酒品质的关系。结果表明,与对照组相比,冷浸渍组的总酸和挥发酸含量分别减少了0.37 g/L和0.16 g/L,依次为4.99 g/L和0.30 g/L,而花色苷、单宁和总酚的含量显著增加,依次为385 mg/L,1.574 g/L和2.335 g/L。与各自对照组相比,合理的冷浸渍工艺在提升葡萄酒的香气纯正度、浓郁度和香气质量方面具有一定的优势。因此,合理的冷浸渍处理可以改善黑比诺干红葡萄酒的理化和感官品质,适合在生产优质黑比诺干红葡萄酒的工艺中采用。     

Effects of climate and anthocyanin variables on the zoning of Pinot Noir wine from the Casablanca Valley

The Casablanca Valley is one of the youngest wine grape regions of the Chilean appellation of origin. The growers of this area note the presence of microclimates within the valley as one of its main features. These microclimates have historically been associated with two geographical zones: the Zona Alta and the Zona Baja. The objective of this research was to explore the effects of climate variables and anthocyanin profiles in Pinot Noir wines of the Casablanca Valley as a differentiator of productive zones. The climate variables were measured using weather stations located at different points across the valley. Wine samples from the same locations were characterised according to their anthocyanin profiles. The data were processed using analysis of variance, principal components analysis and partial least squares discriminant analysis to determine differences between the two groups explored. The results indicate a strong correlation between variables and zones (98.3% R²Y), leading to the conclusion that there are significant differences between the Zona Alta and Zona Baja group. Finally, the existence of a vineyard that does not belong to the Zona Baja group suggests a reassessment should be performed of the vineyards belonging to the administrative areas defined as part of the Casablanca Valley.     

Extraction of phenolic compounds during vinification of Pinot Noir wine examined by HPLC and cyclic voltammetry

The phenolic profiles of four Pinot Noir fermenting musts were examined over a period of 18 days prior to barrel storage, using HPLC levels of individual polyphenols, the Folin-Ciocalteu assay and absorbance at 280 nm for total phenols, and the cyclic voltammetry response of the musts, diluted in a pH 3.6 model wine solution, for their activity as reducing agents. These methods showed the early extraction of various hydroxycinammates from the grape, followed by skin anthocyanins and flavonol glycosides, and high levels of flavan-3-ols from the seeds towards the end of the fermentation. The appearance of the individual phenolics was matched by cyclic voltammetry peaks at electrode potentials expected for each compound. Cyclic voltammetry also produced a semi-quantitative measure of the level of galloyl and catechol groups present, which correlated well with other total phenol measures.     

Effect of mechanical leaf removal and its timing on flavan‐3‐ol composition and concentrations in Vitis vinifera L. cv. Pinot Noir wine

Background and Aims: Mechanical leaf removal of Pinot Noir vines was carried out in a commercial vineyard in Waipara, New Zealand in the 2007–2008 and 2008–2009 growing seasons. The aim was to investigate the effects of different timings on flavan‐3‐ol composition and concentrations in Pinot Noir wine produced from the treatments. Methods and Results: Treatments were leaf removal from the fruiting zone 7 days after flowering, 30 days after flowering and at veraison (by visual assessment), and no leaf removal (control). Proanthocyanidin concentrations in berries by the methylcellulose precipitation assay at harvest showed no difference between treatments, although the LR7 wine had the highest methylcellulose precipitable tannin concentration in 2007–2008, the LR30 wine had the highest concentration in 2008–2009 and the NLR wine had the lowest in both years; the 2009 wines had increased concentrations compared to 2008. Greatest concentrations of flavan‐3‐ol monomers by reverse phase high performance liquid chromatography were found in LR7 wines. An increase in the ratio of 2,3‐trans to 2,3‐cis flavan‐3‐ols was observed with earlier leaf removal. The mean degree of polymerisation (mDP) by acid catalysis in the presence of phloroglucinol showed no statistical difference between wines. Conclusions: Early timing of mechanical leaf removal increases proanthocyanidin concentration, but has no influence on the mDP. Increased severity of defoliation and/or higher alcohol levels in the 2008–2009 growing season were responsible for the differences in total tannin concentration compared to the previous year. Significance of the Study: The timing of mechanical leaf removal can influence wine flavan‐3‐ol concentrations.     

Excessive nitrogen supply and shoot trimming can impair colour development in Pinot Noir grapes and wine

We investigated the effects of nitrogen supply and shoot trimming on mature, field-grown Pinot Noir ( Vitis vinifera L.) vines. Ammonium nitrate (0, 30, 60, 90 kg N/ha) was applied at the beginning of flowering. Shoots were topped either once (at fruit set), or twice, (at fruit set and during the lag-phase of berry growth). Neither treatment affected grape berry and skin weights, yield and grape sugar, but high rates of nitrogen increased malic acid and reduced skin phenols, flavonols and anthocyanins. Malvidin-3-glucoside was the most abundant anthocyanin in skins and wine. It accounted for 75% of the total anthocyanins at the beginning of fermentation and its relative proportion increased to 95% in the finished wine.
Increases in anthocyanin concentration at the beginning of fermentation and before malolactic fermentation, were followed by declines during the later stages of alcoholic and malolactic fermentation. High nitrogen supply decreased anthocyanins in the juice and wine, increased pH and increased the percentage of malvidin-3-glucoside. Repeated shoot topping gave lower wine total phenols and anthocyanins and thus enhanced the nitrogen effect. Wine susceptibility to oxidation increased with higher pH and lower anthocyanin content. The best treatment combination for fruit and wine quality, in terms of colour and oxidative stability, was low nitrogen/single topping and the worst combination was high nitrogen/repeated topping. These results suggest that a combination of high rates of nitrogen fertiliser and repeated shoot trimming can decrease potential fruit and wine quality.     

不同采收期对黑比诺葡萄及葡萄酒品质的影响

为研究不同采收期对黑比诺葡萄及葡萄酒品质指标的影响,于葡萄转色后每7 d取样1次,监控葡萄果实理化指标及多酚含量的变化,并对不同采收期葡萄酿造的葡萄酒感官指标进行定量描述分析(QDA),以确定宁夏青铜峡黑比诺葡萄的最佳采收期;对不同采收期葡萄和葡萄酒的多酚指标进行主成分分析(PCA),筛选出对其品质影响最大的指标,达到简化实用的目的。结果表明,在葡萄成熟过程中,还原糖含量、糖酸比不断增加,总酸含量不断降低;果皮和籽中的多酚指标含量基本都呈先降低后逐渐升高的趋势;QDA分析结果表明,随着采收期的推移,相应葡萄酒的感官质量也逐渐提高;PCA分析结果表明,籽总类黄酮、皮总类黄酮和皮总花色苷对葡萄及葡萄酒品质的影响最大,并且其含量分别达到52.02±0.13 mg/g,29.95±0.28 mg/g和7.09±0.02 mg/g时,葡萄多酚成熟度相对较好,所酿葡萄酒的品质较佳;以期指导该地区黑比诺葡萄采收期的确定。     

混合酵母菌发酵对黄酒品质的影响研究

以混合酵母菌酿制的黄酒各项理化指标均符合标准要求,其特点是酯的种类和含量比单一酵母菌酿制的对照酒多,高级醇的种类和含量少于对照酒,醛类、氨基酸(尤其是苦味氨基酸)、乳酸的含量均低于对照酒。感官品评显示,以混合酵母菌酿制的黄酒无新酒刺鼻味,有陈年酒的香气,香气明显优于对照酒。     

嗜杀酿酒酵母对海南山兰甜酒发酵品质的影响

以海南坡稻山兰为主要原料,在传统手工酿造山兰甜酒的工艺基础上添加嗜杀酿酒酵母作为发酵剂能保持山兰甜酒原始的酒醇甘甜微苦风味,维持独特的米脂芳香。控制和净化发酵醪中的酵母品质,在发酵过程中保持酒味纯正,使糖化与发酵得到同步,发酵力得到加强,酒味更加醇厚。同时发酵环境得到净化,发酵时间缩短,生产效率提高。嗜杀酵母发酵剂令山兰甜酒出现苦味物质的时间提前,同时相对传统工艺生成较高浓度的高级醇,可采取定时移除酒液的方法解决。     

含糖量对山葡萄酒苹果酸-乳酸发酵的影响

以东北高寒地区产的山葡萄酿造的山葡萄酒为研究对象,探究山葡萄酒苹果酸-乳酸发酵过程中含糖量对其pH值、总酸、苹果酸-乳酸转化程度、总糖的影响。山葡萄酒中的葡萄糖含量对其pH值的升高、总酸的降低及苹果酸乳酸转化程度均有影响。在4个梯度葡萄糖含量的山葡萄酒中,含糖量为10.67 g/L的山葡萄酒其pH升高值（0.18）、总酸度降低值（6.05 g/L）最大,苹果酸乳酸转化程度最高。     

果酒发酵酵母菌株的发酵性能初探

针对一株用于猕猴桃及橙子果酒发酵皆较优的酿酒酵母GJ-JS1,初步探索其各项发酵特性,对其发酵条件筛选得到：初始糖度0.115g/mL,初始pH值应控制在2.8~3.4之间为宜,发酵初始菌浓度2.32×104个/mL。对GJ-JS1进行耐受实验得到：该菌株发酵时间最好控制在24h~36h内,发酵pH值不低于3.2,综合分析得发酵酸度以pH3.2~3.4为宜。酒精度可控制于6%vol左右,糖浓度不高于200g/L,有利于菌株生长。     

The effect of Saccharomyces cerevisiae and Saccharomyces bayanus yeast on colour properties and pigment profiles of a Cabernet Sauvignon red wine

Red wine was made from the same batch of Cabernet Sauvignon grapes but with two different yeasts, Saccharomyces cerevisiae (SC) or Saccharomyces bayanus (SB). The colour properties and pigment profiles of SC and SB wines were compared at 8 days and 387 days after yeast inoculation. Grape anthocyanin concentration was found to be lower in SB wines than in SC wines at day 8 and 387, but SB wine exhibited greater wine colour density, a* and b*. The anthocyanin concentration did not correlate with wine colour density. The levels of pigmented polymers and SO₂ non-bleachable pigments were found to be higher in SB wine at day 387, demonstrating that the formation of stable pyranoanthocyanins and pigmented polymers was enhanced by SB yeast. Electrospray mass spectrometry was used for the compositional analysis of pyranoanthocyanins, and direct and ethyl-bridged linked condensation dimers of malvidin 3- O -glucoside (MvG) with flavanols (catechin or epicatechin). The data demonstrated that the formation of acetaldehyde-mediated pigments was enhanced by the use of the SB yeast. The compositional analysis suggested that the differences in colour properties and pigment profiles of SC and SB wines were largely due to the greater production of acetaldehyde-mediated pigments by the use of SB yeast.     

活性干酵母活化时间与级数对葡萄酒发酵的影响

研究活性干酵母活化方式对葡萄酒发酵的影响。 分别将活性干酵母进行不同时间（25 min、3 h 15 min、24 h 15 min）和不同级 数（两级和三级）的活化,将等量的酵母种子活化液接种到24 °Bx模拟葡萄汁中,24 ℃条件下发酵18 d。 结果表明,活化3 h 15 min的酿 酒酵母生长代谢能力强,在葡萄汁中生长繁殖迅速,耗糖快;产乙醇较多（60.88 g/L）;产乙酸较少（0.77 g/L）。 进行三级3 h 15 min活化 的酵母活性高,活酵母菌浓度较大（最高4.53×107 个/mL）,不同级数活化的酵母在发酵过程中还原糖含量差异显著（P＜0.05）,CO2生 成量、乙醇和乙酸含量无显著差别（P＞0.05）。