Examination of the sulfur dioxide–ascorbic acid anti‐oxidant system in a model white wine matrix

The effectiveness of sulfur dioxide in inhibiting the ascorbic acid induced oxidation of (+)‐catechin in a matrix simulating white wine was investigated. At a sulfur dioxide:ascorbic acid mole ratio of 0.8:1.0, sulfur dioxide extended the delay prior to the onset of (+)‐catechin browning as measured by the increase in absorbance at 440 nm from 2 to 4 days post reaction initiation. The lengthening of the pre‐browning period was correlated with an increase in the time required to oxidise ascorbic acid completely, the sequence of events being loss of sulfur dioxide (day 3), loss of ascorbic acid (day 4) and on‐set of (+)‐catechin browning (day 4). Increasing the sulfur dioxide to ascorbic acid mole ratio to 3.0:1.0 inhibited the onset of (+)‐catechin browning over the 14‐day reaction period. This inhibition was achieved at considerable cost to the sulfur dioxide concentration, with the ratio of sulfur dioxide consumed to ascorbic acid oxidised being 1.7 compared with the expected fraction of 1.0. Reasons for the enhanced consumption of sulfur dioxide and the implications of this study for maintenance of quality in white wine production are discussed. Copyright © 2004 Society of Chemical Industry     

Flavour and vitamin stability in pasteurized milk in polyethylene-coated cartons and in polyethylene bottles

Commercially pasteurized, non-homogenized full cream milk in 2-pt white polyethylene (PE)-coated cartons overprinted with blue, and in 4-pt PE bottles was stored for 4 d in the dark or under white fluorescent light of 4000 1x, at a temperature of 7°C. The flavour of milks kept in the dark remained good, but exposure to light resulted in early off-flavour development: cartoned milk was disliked by a flavour panel after about 17.5 h exposure and milk in the PE bottles after 9 h. Vitamins A and B₂ were stable in the milk during 4 d storage in the dark in both bottles and cartons, and in cartons exposed to light. In the bottled milks, light-induced losses of these vitamins after 4 d were, respectively, 15% and 35%. but there was little or no loss before the development of light-induced flavour. Loss of total vitamin C by day 4 was about 50% in the dark, irrespective of container. In the cartons exposed to light, 66% of the vitamin C was lost, while virtually none remained in the exposed, bottled milk. There was also a markedly greater loss of vitamin C in the bottled milk than in the cartoned milk at the time the flavour became unacceptable. The dissolved O₂ concentration dropped considerably in the bottled milk exposed to light, but only marginally in the cartons. There were small increases in dissolved O₂ in the dark in both types of container.     

HPLC-DAD–MS/MS characterization of phenolic compounds in white wine stored without added sulfite

The oxidation of dihydroxybenzene and hydroxycinnamate compounds generates unstable quinones which undergo further reactions to combine nucleophilic compounds. These reactions are limited when sulfur dioxide (SO₂) is used as wine preservative, as SO₂ plays an important role in reducing quinones back to their phenol form. In no sulfite-added wine, oxidation chemistry undoubtedly results changed. Therefore, in this work, the phenolic profile of a white wine without adding sulfites, after twelve-month storage, was investigated by HPLC-DAD-MS/MS and compared to a control stored with sulfur dioxide. A total of twenty-six phenolics were detected including hydroxycinnamate derivatives and minor compounds resulting from oxidation processes, i.e. oxidized caffeic acid dimers, whose structures were tentatively proposed on the basis of their UV, MS, and MS/MS typical fragmentation. The experimental evidence of these latter is described for the first time in wine stored without added sulfites, and it may contribute to get new insight in the field of wine oxidation processes.     

The impact of closure type and storage conditions on the composition, colour and flavour properties of a Riesling and a wooded Chardonnay wine during five years' storage

This paper presents the results from an investigation to assess the development of a Riesling and a wooded Chardonnay wine over five years following the imposition of several treatments at bottling. The wines were bottled under a screw cap closure, two different natural corks, a synthetic closure and in a glass ampoule. In addition, the effect of storage orientation was investigated. The bottled wines were stored under controlled temperature and humidity conditions. Various analyses were carried out on replicate bottles from each treatment, including sulfur dioxide and ascorbic acid concentration, sensory analysis of appearance and aroma attributes, and spectral measures. The largest treatment effect resided with the nature of the closure. Wines sealed with the synthetic closure were relatively oxidised in aroma, brown in colour, and low in sulfur dioxide compared to wines held under the other closures. A struck flint/rubber ( reduced ) aroma was discernible in the wines sealed under the screw caps or in glass ampoules. Wines sealed under natural bark corks in this study showed negligible reduced characters. The bottle orientation during storage under the conditions of this study had little effect on the composition and sensory properties of the wines examined.     

Contribution of wine components to inactivation of food-borne pathogens

ABSTRACT:  Wine is a complex solution containing several components with several likely antimicrobial properties. Low pH (3.0 to 4.0), high organic acid content (titratable acidity ≥6.0 g/L tartaric acid), relatively high ethanol (10% to 15%), and potentially high total sulfur dioxide (0 to 300 ppm) may contribute to inactivation of food-borne pathogens when exposed to wine. The objective was to determine the effect of these 4 parameters on reducing populations of Escherichia coli ( E. coli ) O157:H7 and Staphylococcus aureus . A factorial design was used to test variables (pH, titratable acidity, sulfur dioxide, ethanol) in combinations of low, medium, and high levels. Suspension tests were performed to compare the efficacy of 81 treatments with controlled exposure time of 20 min. Staphylococcus aureus was significantly more resistant to wine treatment than E. coli O157:H7. Stepwise regression analysis of S. aureus inactivation revealed the ordered impact of pH, molecular sulfur dioxide, titratable acidity, and ethanol concentration. Selected analysis of E. coli inactivation revealed the importance of pH and ethanol in predicting inactivation. Total and free sulfur dioxide were not predictive of inactivation of either pathogen. Wine-based solutions may have application as surface disinfectants for food surfaces and food contact equipment. Wine destined to be used as a disinfectant could be enhanced by increasing any of the parameters tested in this study; however, lowering the pH would be the most effective and would likely enhance the efficacy of the other parameters. Additional wine components such as volatile acidity and phenolics were not evaluated but may also contribute to the antimicrobial properties of wine.     

The chemical and sensorial effects of lysozyme addition to red and white wines over six months' cellar storage

Lysozyme is an enzyme with muramidase activity which can lyse Gram-positive bacteria, including wine lactic acid bacteria. This enzyme provides a practical method for delaying or preventing the growth of Oenococcus oeni and consequently the onset of malolactic fermentation during the vinification of red and white wines. This paper reports the impact of lysozyme on the chemical and sensorial properties of commercially vinified red (Cabernet Sauvignon and Shiraz) and white (Riesling) wines. The addition of lysozyme to these wines had little or no effect on the content of alcohol, free and total sulfur dioxide and titratable acidity, and pH value. The lysozyme retained 75–80% activity in the Riesling wine after six months, however no detectable activity remained in the Cabernet Sauvignon and Shiraz wines after two days. Upon addition of lysozyme to both of the red wines, a rapid initial decrease (up to 17%) in red wine colour density and phenolic content occurred in association with the formation of a light precipitate. The reduction in red wine colour was also noted by the sensory panel. When added to the Riesling wine, lysozyme did not cause an increase in browning over the six month storage time, but did induce heat instability (haze), suggesting that white wines may require protein stabilisation following treatment with lysozyme. Sensory assessment by triangle difference testing revealed that, during the six month storage period, treatment with lysozyme did not cause important changes to either the aroma or palate of the red and white wines tested.     

橡木桶陈酿技术对猕猴桃酒品质的影响

为了提高猕猴桃果酒的品质,本文研究了采用橡木桶进行陈酿过程对猕猴桃果酒理化指标和感官评价的影响,具体包括溶解氧、电导率、色度和色调等物理指标,游离二氧化硫、总酚、高级醇等化学指标和感官评价得分。结果显示:随着猕猴桃果酒陈酿时间的延长,电导率、色度、色调等理化指标均呈现了明显的上升趋势,且逐渐趋于平衡,分别为电导率2.76 mS/cm,色度0.375,色调4.05;而溶解氧、游离二氧化硫、总酚等理化指标均呈现了明显的下降趋势,并逐渐趋于稳定,溶解氧0.72 mg/L,游离二氧化硫27.87mg/L,总酚332mg/L;随着陈酿时间延长,异丁醇、异戊醇和高级醇总含量都呈现下降趋势;经过橡木桶陈酿后的猕猴桃果酒其感官得分为97.68,明显高于感官得分为79.84的玻璃瓶贮藏的猕猴桃果酒样品。因此,贮藏过程中猕猴桃酒理化和感官评价变化与溶解氧含量及变化、橡木桶结构和成分有关。     

EFFECT OF TIME AND STORAGE CONDITIONS ON MAJOR VOLATILE COMPOUNDS OF ZALEMA WHITE WINE

ABSTRACT

Changes in quality attributes during bottled storage of white wine were studied. Different storage conditions, temperature, bottle position and exposure to light were studied over 1 year and their effects on major volatile compounds were evaluated. Ethyl lactate and diethyl succinate contents increased after 12 months of storage, whereas isoamyl acetate decreased over this period. The analysis of variance revealed that the temperature had a statistically significant effect on most volatile compounds studied. Multivariate statistical techniques (specifically principal component analysis and linear discriminant analysis) confirmed that temperature is the most important factor, so the samples were distributed into two groups according to storage temperature. A rough differentiation among wines according to the length of storage was also obtained using linear discriminant analysis.

PRACTICAL APPLICATIONS

Aroma is one of the main factors contributing to the quality of wines and their acceptance by consumers. However during bottle storage, young white wines lose their fresh and fruity flavor and suffer a browning process. Among other factors, the time it takes a wine to spoil depends on the wine composition and on storage conditions. Knowledge of the bottle storage stability of Zalema young white wines could allows us to predict their shelf life and establish the best commercial storage conditions to retain their organoleptic characteristics for longer periods.     

低醇半干白葡萄酒的酵母菌耐受性研究

为了考察低醇半干白葡萄酒的酵母菌稳定性,进行山梨酸钾和游离二氧化硫不同浓度的梯度实验,以确定该产品酵母菌的安全耐受浓度.实验结果表明低醇半干白葡萄酒的山梨酸钾的适宜添加浓度为150mg/L,游离二氧化硫浓度为30mg/L～35mg/L,在此基础上酵母菌的安全耐受浓度为酵母菌数＜50个/100mL酒样.     

The role of corks in oxidative spoilage of white wines

The permeability of corks to oxygen was examined by comparing the level of browning and the concentration of the antioxidants, free and total sulfur dioxide and ascorbic and erythorbic acids in wines bottled and sealed with two cork types and stored in an atmosphere of either nitrogen, oxygen or air. Three different batches of corks that had been treated with peroxide during processing, representing one cork type, and a batch of corks that had been treated with chlorine during processing representing the second cork type, were taken for the study. In bottled wines stoppered with one of the peroxide-treated corks (Cork A), there was a higher level of browning and a greater loss of the antioxidants in those wines in bottles stored under oxygen and air than that in the wines in bottles stored under nitrogen, indicating that corks of this batch were permeable to oxygen. There was no significant difference in the loss of ascorbic and erythorbic acid or the level of browning from bottled wines stored under the three gases and sealed with the chlorine-treated corks (Cork C). For the other two peroxide-treated corks (Corks B and D), there was no significant difference in the level of browning or loss of the antioxidants from bottled wines stored under the three gases and sealed with Cork B, nor was there a significant difference in the level of browning or loss of free or total sulfur dioxide from bottled wines stored under the three gases and sealed with Cork D. From comparative data, it was evident that oxidation of the wines sealed with Corks B and D was due to compounds in the corks rather than oxygen permeation through the corks, or oxygen ingress at bottling. Because the bottles of wine selected for this study were from batches that had already exhibited sporadic oxidation, the results found are indicative, but not necessarily representative, of the properties of all peroxide- and chlorine-treated cork types used in the wine industry.     

Detection of Traces of Ovalbumin and Casein in White and Red Wines by Quantitative Western Blotting

Fining of wine with agents containing cow's milk or hen's egg white is a common and traditional procedure. In light of increasing food allergies all over the world, the presence of fining residues has been subject of intense debate. Switzerland does not make exception, and since 2009 the Federal Department of Home Affairs has modified its food regulations stating that the labels must show if traces of fining agents are present. Nevertheless, the application of this regulation is not based on an official analytical method. In this study we show that immunoblotting is an efficient technique to detect and quantify ovalbumin and casein residues in bottled wine. We showed that final filtration is an essential step to remove finings in red wine, and that overfining of white wine may result in fining residues in finished products. Finally, for the first time in Switzerland, 22 samples were taken by food safety inspectors and officially analyzed for the regional food control authority of the Canton of Vaud. These samples were allergen free, but a larger study is currently planned in collaboration with other regional authorities of Switzerland to complete these results and make a complete picture of the Swiss wine production.     

APPLICATION OF MULTIVARIATE STATISTICAL ANALYSES TO THE STUDY OF FACTORS AFFECTING WHITE WINE VOLATILE COMPOSITION

ABSTRACT

The influence of different storage conditions on the volatile composition of young white wine was evaluated during 1 year of storage. The wine was bottled and stored under different conditions of temperature, position and illumination. During storage, a significant increase in total content esters (mainly due to the increase in ethyl butyrate, ethyl acetate and diethyl succinate) and total content acids was detected. Also total content alcohols and carbonyl compounds decreased during storage. Storage time, temperature and illumination have a significant effect on esters content, whereas carbonyl compounds are affected by temperature, and alcohols content is affected by illumination. Stepwise linear discriminant analysis was applied to the experimental data. The results showed that the samples were well classified as a function of storage temperature. On the other hand, a certain trend was observed when the wine samples were classified according to storage time. The samples corresponding to two and four months of storage were well differentiated from the rest.

PRACTICAL APPLICATIONS

From a sensory point of view, the aroma influences greatly the quality of wines. The loss of aromatic characteristics in young white wine, as well as browning, take place over a variable period of time which ranges from one month to several years, depending on wine type and storage conditions. Assessment of possible factors affecting the useful lifespan of young white wine is of great interest for the wine making industry. Knowing the chemical composition of wine, specifically aromas, and its evolution relating to different storage and preservation conditions is an important tool in quality control.     

The impact of high voltage electrical discharge plasma on the chromatic characteristics and phenolic composition of red and white wines

The cold plasma is an emerging electrotechnology for the improvement of food safety without loss of physicochemical or sensory properties. The purpose of this study was to evaluate the effects of plasma treatments on the chromatic characteristics and phenolic composition of red and white wines. The red wine Cabernet Sauvignon and white wine Graševina were treated with high voltage electrical discharge plasma considering the variations in frequency (60, 90 and 120 Hz) and processing time (3, 5 and 10 min). Total phenolics, total anthocyanins, total tannins and chromatic characteristics were analyzed by spectrophotometry while free anthocyanins, phenolic acids and flavan-3-ols by the HPLC-UV/Vis. Obtained results illustrated that plasma treatments have influenced the stability of phenolic compounds in wines without major changes in color parameters. Also, among two different processing parameters, the duration time was the most significant factor inducing changes on wines.Industrial relevanceHigh voltage electrical discharge plasma has been shown to affect the stability of wine phenols without any significant change in the color. An increase in the concentration of certain phenolic compounds in white wine suggest that this technique could be used in the wine industry as an alternative technique for enhancing the oxidative stability of wine and consequently the wine quality during the aging process.     

Effect of Marinading with Wine, Sodium Bicarbonate or Soysauce on the Thiamin Content of Beef

The thiamin content of marinated bovine longissimus dorsi muscle was determined after cooking. The marinades were three white wines, two red wines, sodium bicarbonate solution, or soysauce. Distilled water was used as a control. The destruction of tbiamin was proportional to the sulfur dioxide content of the wine. The greatest loss of thiamin (75%) occurred with a white wine containing 450 ppm sulfur dioxide. The red wines contained no sulfur dioxide and there was no loss of thiamin after marinating and cooking despite the high tannin content. Marinating with sodium bicarbonate resulted in a significant loss of thiamin from 103 to 46 μ/100g meat, while meat marinated and cooked with soysauce contained 56 μg thiamin/100g meat.     

不同抗氧化剂对白葡萄酒品质的影响

将甘露聚糖、谷胱甘肽加入瓶装葡萄酒中，检测不同处理后白葡萄酒在储存期间颜色、酚类化合物和香气的变化，并通过感官品评来评估抗氧化剂对葡萄酒品质的影响。结果表明，添加20 mg/L甘露聚糖能有效抑制白葡萄酒颜色褐变，降低白葡萄酒的黄、绿色调及色差，提升酒体明亮度；显著延缓儿茶素和表儿茶素的氧化速率（高于对照组61.9%、39.7%），提高没食子酸的浓度（56.91%），但总酚含量总体呈递减趋势，表明抗氧化剂选择性保护了部分酚类物质；有效降低辛酸乙酯，乙酸异戊酯等酯类物质的水解（高于对照组2.97～5.77倍），保护了葡萄酒的花香味；并减少辛酸、己酸和正葵酸等酸性化合物的含量（低于对照组59%、70.07%和91.24%），降低了葡萄酒的奶酪腐败味；添加20 mg/L甘露聚糖白葡萄酒感官评分最高，为81分。     

Chemistry of copper in white wine: a review

Copper is one element in wine that has considerable notoriety. While current winemaking practice tends to minimise the amount of copper that results from vineyard and winery sources, the addition of copper(II), either as its sulfate or citrate, to remove sulfidic off‐odours may result in an elevated concentration in the finished (bottled) wine. Residual copper in white wine has been linked to oxidative and reductive spoilage processes, although the mechanisms are at times speculative. The presence of copper has been implicated in haze formation (copper casse) and linked to protein instability. More recent concerns include the coexistence of residual copper and hydrogen sulfide in wine stored under low oxygen conditions. The chemistry of copper is important in both white and red wine. While there are some overlapping issues, especially with respect to sulfidic off‐odours, both white and red wine display their own unique chemistry. Thus, this review describes the state of knowledge of copper in white wine, differentiating between evidence‐based claims and speculation. It also identifies areas of research that will provide a much clearer understanding of the role of copper in wine spoilage.     

果酒中二氧化硫及其控制技术的研究进展

果酒酿造中的二氧化硫控制是重要的食品安全研究课题。该文综述了二氧化硫在果酒中的主要作用、存在形式、对酿酒酵母、酒类酒球菌等活力的影响以及二氧化硫控制技术的研究进展,以期为控制果酒中的二氧化硫提供参考和借鉴。     

不同酿酒酵母对柑橘果酒香气成分的影响

研究不同来源酿酒酵母对柑橘果酒香气成分的影响,以锦橙表皮和柑橘园土壤为酵母的来源,经培养、分离、纯化、初筛和复筛得到适于柑橘果酒酿造的酵母菌株。确定其最适生长温度、pH 值及对乙醇和SO2 的耐受性,并用GC-MS 分析其对柑橘果酒香气的影响。结果显示：筛选得到3 株酵母菌L3、L5、L9,其最适生长温度为28～30℃,最适pH 值在3.5 左右,其中L3 耐低温和高温的能力最强,L9 乙醇耐受力最强,L5 对SO2 的耐受能力最强。3 株酵母所酿柑橘果酒的香气成分有特异性差异,庚酸乙酯、萜品油烯等13 种物质为L3 酵母菌所酿柑橘果酒独有;月桂醇、乙酸异丁酯等8 种物质仅见于L5 酵母菌所酿柑橘果酒中;正辛醇、5- 甲基呋喃醛等4 种物质只在L9 酵母菌所酿柑橘果酒中存在。     

不同终止发酵方法制备低醇菠萝酒

本研究对比探讨了热处理、添加二氧化硫和脉冲电场灭菌等方法终止菠萝酒半发酵的工艺及产品质量情况。结果表明:脉冲电场方波有效处理时间80μs,场强15 kV/cm或75℃水浴恒温20 min或添加150 mg/L二氧化硫均可达到终止发酵目的;不同终止发酵方式主要影响果酒的色泽、香气和感官分析,对低醇酒的酒精度、总酸、干浸出物等基础理化指标没有显著性影响。脉冲电场灭菌处理的低醇菠萝酒,L^*值、a^*值升高,b^*值降低,色泽优于其他组;低醇菠萝酒特征香气成分2-甲基丁酸甲酯(4.71 mg/L)、丁酸乙酯(1.20 mg/L)、2-甲基丁酸乙酯(0.58 mg/L)、4-羟基-2,5-二甲基-3(2H)-呋喃酮(0.46 mg/L)、3-羟基己酸甲酯(0.36 mg/L)含量均高于传统终止发酵法。结合感官评价综合分析,脉冲电场终止发酵法制备的菠萝低醇酒优于传统的终止发酵方式。