Stability of copigmented anthocyanins and ascorbic acid in muscadine grape juice processed by high hydrostatic pressure

ABSTRACT:  Intermolecular copigmentation is one of the mechanisms of stabilization of anthocyanins in nature and is also responsible for the characteristic color and stability of aged red wines. In the present study, the effect of polyphenol oxidase (PPO) activity on phytochemical stability of an ascorbic acid-fortified muscadine grape juice following high hydrostatic pressure (HHP) processing (400 and 550 MPa for 15 min) and after 21 d of storage at 25 °C was investigated. Addition of rosemary and thyme polyphenolic extracts (copigmentation) was evaluated as a means to stabilize anthocyanins and ascorbic acid during pressurization and subsequent storage. Polyphenolic extracts were partially purified in order to reduce their content of PPO substrates, and improve their stabilization properties within juice matrix. Overall PPO activity increased (3- and 2.5-fold) following HHP at 400 and 550 MPa, respectively, although it was significantly lower in copigmented treatments. Higher anthocyanin losses occurred at 400 (∼70%) than at 550 MPa (∼46%), which were correlated to antioxidant losses ( r = 0.89). Similarly, greater ascorbic acid losses were observed at 400 (84%) than at 550 MPa (18%). Copigmentation increased anthocyanin retention in reference to pressurized controls (3- and 3.2-fold for rosemary and thyme treatments, respectively) and decreased ascorbic degradation (20 to 32%). In stored samples, higher anthocyanin content (>2-fold) and antioxidant capacity (>1.5-fold) was observed for copigmented treatments when compared to control juices. Addition of partially purified copigments increased muscadine grape juice color, antioxidant activity and also reduced phytochemical losses during HHP processing and storage.     

Formation and occurrence of flavor components in Noble muscadine wine

Flavor development in Noble muscadine wine during fermentation and aging was determined with a combined gas chromatograph-mass spectrometer. The source of 2-phenylethanol, a major aroma component of the wine, is predominantly through biosynthesis during the vinification process, although the alcohol was also found to be present in fresh muscadine grape skin. The involvement of substituted benzene derivatives in the formation of phenyl ethanol during fermentation and aging of wines is proposed. The complexity of the volatile aroma extracts increased with time, especially after fermentable sugars were exhausted. Anaerobic formation of fatty acid esters also commenced after active fermentation had ceased. These compounds constitute major components of the aged muscadine wine. Effluent sniffing indicated that many odorous compounds including phenyl ethanol and methyl succinate contribute significantly to the muscadine wine aroma.     

Grape pigment phenomena: Interpretation of major colour losses during vinification

Large decreases in colour density during the making of red wines, whether by the traditional fermentation on skins or by thermovinification, have not previously been explained in terms of juice and wine composition. The major colour loss is actually due to the extreme instability of deeply coloured pigment structures initially present in the juice extract to ethanol, whereas decrease in anthocyanin content is a minor contributing factor. The consequent decline in colour density during fermentation can be as much as five-fold under conditions of high pH. Both red and blue chromophoric forms of the anthocyanins, in self-association and co-pigmentation with related flavonoid phenolics, are proposed as being present in the juice pigments. The stability of such complexes is ascribed to intermolecular hydrogen bonding forces. The existence of two nearly distinct phases in the accounting of total phenolics during ‘evolution ’of a red wine is emphasised.     

Extracts from red muscadine and cabernet sauvignon wines induce cell death in MOLT-4 human leukemia cells

Red wine contains a diversity of polyphenolic compounds that exert beneficial health effects including anti-cancer effects. This trial evaluated the anti-proliferative potential of red muscadine (Vitis rotundifolia) and red cabernet sauvignon (Vitis vinifera) wines in cell culture. Chemical properties of wines were determined by HPLC-PDA analysis and concentrated extracts of each wine were evaluated before and after glycosidic hydrolysis in MOLT-4 leukemia cells. Cell growth and the induction of apoptosis were evaluated after exposure to various extract dilutions. Wine extracts reduced cell viability up to 68% and cell numbers up to 50% after 48 h with muscadine extracts being more effective than cabernet sauvignon. Caspase-3 activity was induced similarly by all extracts in a dose dependent manner. Cell cycle arrest in the G₂/M phase was observed for both muscadine and the non-hydrolyzed cabernet sauvignon extract. Collectively, extracts from both wines exerted anti-cancer effects in leukemia cells.     

酿酒酵母F15和CC17共接种发酵对赤霞珠葡萄酒品质及感官特性的影响

为解决使用单一商业酵母菌株发酵引起的葡萄酒“同质化”问题,本研究以河北昌黎产赤霞珠葡萄为原料,以商业酿酒酵母（Saccharomyces cerevisiae）F15和本土优良酿酒酵母CC17为发酵剂进行单菌株和双菌株共接种（F15:CC17=1:1）发酵,同时监测酒精发酵过程中比重、温度、残糖、乙醇、总酸、pH、花青素、单宁、总酚、色度和色调的变化。发酵结束（192 h）后,分别对酒的香气成分和感官特性进行了测评。结果表明:与F15单菌株发酵相比,双菌株共接种发酵能够提高赤霞珠葡萄酒中花青素、单宁和总酚含量,增加酒的色度并使色调更趋向于红色;与CC17单发酵相比,共发酵组残糖、总酸含量较低;共发酵调谐主要香气成分,并增加饱和脂肪酸乙酯的含量。此外,感官评价结果表明共发酵葡萄酒色、香、味均优于F15单独发酵。因此,在酒精发酵过程中采用商业酵母与本土菌株共发酵是改善葡萄酒品质和感官特性有效方法。     

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。     

Effect of the prefermentative addition of copigments on the polyphenolic composition of Tempranillo wines after malolactic fermentation

The influence of the prefermentative addition of copigments and different winemaking technologies on the polyphenolic composition of Tempranillo red wines after malolactic fermentation was studied. Six experiments dealing with the prefermentative addition of caffeic acid, rutin, (+) catechin, white grape skin tannin, white grape seed tannin and control wines were realised. Three different winemaking technologies (traditional vinification, prefermentative cold maceration at 6–8 °C and cold soak at 0–2 °C with dry ice) were studied. Prefermentative addition of copigments increases anthocyanin copigmentation reactions and produces wines with a greater colour, a higher anthocyanin concentration, a superior contribution of anthocyanins to the colour of the wine, a superior percentage of tannins polymerised with polysaccharides and less astringency. Cold prefermentative maceration increases the extraction of polyphenols, the anthocyanin copigmentation reactions and the polymerisation reactions between tannins and polysaccharides. The effectiveness of the combination of copigments and prefermentative maceration treatments was demonstrated by the increase of the concentration of the polyphenolic compounds.     

Stability of Non-Pasteurized, Refrigerated Muscadine Grape Juice

The stability of nonpasteurized muscadine grape juice processed with and without 100 mg/L potassium metabisulfite was monitored during storage at 3°C. The muscadine flavor intensity, sweetness, off-flavor levels, and color of white juices remained stable, and ethanol levels remained low for 7 wk. However, the flavor intensity and sweetness of nonsulfited white juice decreased, and off-flavor and ethanol levels increased after 7 wk. Sulfite lowered microbial levels in white juice throughout 9 wk. Red juices did not develop significant levels of off-flavors or ethanol during 9 wk, although the flavor intensity declined, especially in nonsulfited red juice. Sulfite lightened the color of red juice, but the color was stable in both sulfited and nonsulfited red juices.     

Blackberry Juice and Wine: Processing and Storage Effects on Anthocyanin Composition, Color and Appearance

Blackberry wine was made from thawed fruit (Evergreen variety) by fermentation of pulp, depectinized juice, and high-temperature short-time (HTST)-treated and depectinized juice. The effects of fining and storage on pigment composition, color and appearance were investigated. Seven anthocyanin pigments (cyanidin-3-glucoside, cyanidin-3-rutinoside, a xylose-cyanidin derivative, two acylated cyanidin derivatives, cyanidin and a polymeric derivative) were detected in the juices and wines by HPLC. Cyanidin-3-glucoside was highly unstable during fermentation. Haze development and sediment formation occurred, and 85 to 100% of total anthocyanins degraded. Blackberry juice that had been HTST-pasteurized, depectinized and fined produced wine with the most stable color and best appearance after storage.     

Copigmentation and anti-copigmentation in grape extracts studied by spectrophotometry and post-column-reaction HPLC

Copigmentation is a very important contributor to colour in young red wines. Further understanding of the copigmentation effect has been elucidated by investigating the contribution of various fractions of grapes – skin, pulp, and seed – in varieties Shiraz, Sangiovese and Pinot Noir. A series of spectrophotometric and HPLC experiments elucidated the effect of this interaction in grape extracts simulating wine conditions. A post-column reaction method was developed to permit the evaluation of the reactivity of each grape anthocyanin with different reagents: pure compounds (quercetin and caffeic acid) and extracts of grape sections (seed, Semillon skin, Semillon pulp). Certain extracts produced a decrease in colour, suggesting that competing equilibria are important in the copigmentation effect and that an “anti-copigmentation” effect is possible. Flavonols appear to be the best copigmentation cofactors, and the concentration of quercetin 3-O-glucoside was found to correlate with the strength of copigmentation. Flavonols appear capable of displacing cofactors derived from seed extracts.     

Impact of Processing Parameters on the Phenolic Profile of Wines Produced from Hybrid Red Grapes Maréchal Foch,Corot noir,and Marquette

Phenolic extraction in hybrid and interspecific wine grape cultivars is poorly understood, especially in terms of the impact of fermentation and enological conditions on condensed tannins and anthocyanins. Following fractionation via solid‐phase extraction and high‐performance liquid chromatography, phenolic profiles of must and wine from red hybrid grape cultivars Maréchal Foch, Corot noir, and Marquette were examined to assess the impact of enzyme and tannin addition, cold soak, and hot press during vinification. Across cultivars, hot press treatments resulted in the greatest extraction of condensed tannin, anthocyanin, and other monomeric phenolic compounds in musts, and treatments that increased skin contact time or cellular degradation during fermentation produced higher concentrations of tannins, anthocyanins, and flavonols. However, these increases were transient, evincing incomplete carryover into finished wines. Depending on initial must extraction, diglucoside forms of anthocyanins were either selectively extracted or selectively retained throughout fermentation when compared to their monoglucoside counterparts. Typical of hybrid grapes, tannin concentrations across cultivars were low, even under hot press conditions. For condensed tannins and anthocyanins, a cultivar‐specific, stable‐state concentration and phenolic profile emerged regardless of fermentation conditions. Due to the high levels of diglucoside anthocyanins and low levels of condensed tannins, it is expected that the color development and profile in these wines produced from hybrid grape cultivars will be dictated by the monomeric anthocyanins and their potential role in copigmentation processes involving other monomeric phenolic species, as opposed to the formation of polymeric color pigments.     

Statistical optimization of ethanol fermentation parameters for processing local grape cultivars to wines

Grape juice from two local grape cultivars viz. Punjab MACS purple and H‐144 was subjected to prefermentation skin treatment. Ethanol fermentation w.r.t agitation rate, temperature, inoculum size, and nutrient supplementation were optimized using Triple M medium following response surface methodology (RSM). RSM results were numerically optimized keeping temperature “in range” for red wine and “low” for white wine which showed agitation rate of 80 ± 1 rpm for 24 hr, diammonium hydrogen orthophosphate supplementation @ 150 mg/100 ml, inoculum size of 6.1 and 6.5% (vol/vol), and fermentation temperature of 24.6 and 21 °C as optimum for ethanol fermentation of red and white wines, respectively. Optimized results were validated on grape juice of Punjab MACS purple and H‐144 cultivars that lead to 12.0 and 11.2 (%vol/vol) ethanol production, respectively. Gas chromatography mass spectrometry analysis revealed the presence of 41 volatile compounds in the form of phenols, alcohols, terpenes, esters, ketones, and amines that add to the nutraceutical and antioxidant value of the wines.

Practical applications

Present study provides the statistical optimized fermentation parameters for red and white wine production separately. Optimization of an efficient processing technology to produce local grape wines will help to reduce the price of wines so that they are available to common masses at affordable costs besides improving the economic status of grape growers in the state and providing valuable information to wine makers to establish winery under North Indian conditions. Use of synthetic grape juice (Triple M media; during off season of grapes) lead to optimization of ethanol fermentation parameters in two separate fashions considering fermentation temperature as key parameter. Gas chromatography mass spectrometry analysis showed the presence of flavonoids, terpenes, and esters increasing nutritive value of product, providing antioxidants to the consuming person.     

Grape seed removal: effect on phenolics,chromatic and organoleptic characteristics of red wine

Winemakers are interested in wines with low bitterness and astringency, and therefore, there is a preference for a higher presence of skin proanthocyanidins in wines. However, the information regarding the effect of reducing or eliminating seed proanthocyanidins from the must or fermenting wine on the characteristics of finished wines is scarce. For this reason, we elaborated a wine using Monastrell grapes from which the seeds had been removed and compared it with a control wine (CW) made from intact grapes. The anthocyanin and proanthocyanidin concentration and profile, and the chromatic and sensory characteristics were studied. The absence of seed proanthocyanidins did not affect anthocyanin concentration, although the proanthocyanidin concentration was 40% lower than in the CW. The copigmentation (CA) study showed that both wines had a similar extent of CA phenomena although colour intensity was higher when seed proanthocyanidins were present. The panellist evaluated the wines elaborated without seeds as being fruitier, less astringent and with an overall higher quality.     

Studies on the copigmentation between anthocyanins and flavan-3-ols and their influence in the colour expression of red wine

With the aim of evaluating the importance of the copigmentation process between anthocyanins and flavanols on the colour expression of red wine, assays were carried out in wine model systems with mixtures of compounds obtained from two Vitis vinifera grape varieties (Graciano and Tempranillo). Spectrophotometric and chromatic analyses were performed to evaluate the magnitude of the copigmentation and the modifications induced in the colour of the solutions. Measurement of the changes in the anthocyanin hydration constant (K_h) was also used to determine the strength of the copigmentation process. All the flavanols assayed induced significant changes in the colour, perceptible to the human eye, of the wine-like anthocyanin solutions at concentrations similar to those that can exist in red wines. The percentage contribution of the copigmentation with flavanols to the colour of the anthocyanin solutions was found to range from 2% to 20%. The extent of this effect was related not only to the concentration of flavanols but also to the qualitative composition of the flavanol preparations, as influenced by the part of the grape (either skin or seed) and the variety considered. Divergences were found between the evaluation of the copigmentation based on chromatic parameters in the CIELAB colour space and that based on the measurement at visible λ_max, as the latter does not consider the integral colour changes produced in the visible spectrum. The results obtained confirmed the importance of the qualitative phenolic composition, determined in the wine by the type of grape and winemaking practices, to the production of an effective copigmentation process.     

Changes in the color components and phenolic content of red wines from Vitis vinifera L. Cv. “Tempranillo” during vinification and aging

Changes in phenolics and color components during vinification and aging of Tempranillo wines were studied. Different phenolics display different diffusion into the must, and with the exception of proanthocyanidins and acetyl-glucoside anthocyanins, with maximum concentration at the end of postmaceration, the rest of the unacylated and coumarated anthocyanins, monomeric flavanols, and hydroxycinnamic acids reached their maximum at the end of alcoholic fermentation. This resulted in a significant increase in both wine color and stable color, mainly due to the formation of copigmentation complexes, although polymeric pigment formation was also important. Malolactic fermentation produced a significant decrease in flavonoid content while nonflavonoid concentrations were maintained, prompting a considerable loss in wine color, despite the dramatic increase in bisulfite-stable color. Wine oak aging did not produce any significant change in the studied parameters, while bottle aging reduced the level of monomeric anthocyanins and flavanols, and hydroxycinnamic acids. However, wine color remained stable due to a significant increase in stable color. Polymerization reactions of anthocyanins prevailed over pigment degradation reactions, and copigmentation was still relevant after 2 years of bottle aging.     

Influence of sour rotten grapes on the chemical composition and quality of grape must and wine

This study evaluated the effect of grape sour rot on wine fermentation and characterized the chemical composition and the sensory changes in wines produced from rotten musts. Microvinifications were performed during two vintages using healthy Trincadeira and Cabernet Sauvignon red grape varieties to which were added grapes affected by sour rot. Increasing sour rot percentages, up to 50%, contributed to a clear decrease in free run must and final wine yields and induced significant changes in grape must chemical composition expressed by the increase in sugar content, total acidity, volatile acidity, anthocyanins, total phenols, and color intensity. After malolactic fermentation, wines from rotten grapes showed higher values of alcohol content, dry extract, reducing sugar content, total and volatile acidity, anthocyanins, total phenols, and color intensity. Despite the higher levels of reducing sugars, the microbial stability was similar to that of healthy wines. The sensorial evaluation, after malolactic fermentation, showed that both types of wine were not statistically different regarding color, aroma, taste, and overall quality. During 6–8 month storage, wines from rotten grapes showed a significant higher percentage of color loss, suggesting that sour rot is responsible for the decrease in color stability. Nevertheless, the results of sensorial analysis demonstrated that the fermentation of grape musts containing up to 30% sour rot yields wines with similar or even higher-quality scores than wines made with healthy grapes.     

Anthocyanin pattern of several red grape cultivars and wines made from them

A high-performance liquid chromatography (HPLC) method with in-line photodiode array detection was applied to separate anthocyanins from red grape skin extracts of several Spanish cultivars, before and after winemaking, and from finished red wines. Data show that, for every cultivar studied, the anthocyanin pattern of the three materials considered (fresh grape skins, crushed grape skins after winemaking, and finished red wines) is quite different. These results may be explained by taking into account the different chemical structures of each anthocyanin and the degradation reactions that should take place during winemaking. On the other hand, the HPLC fingerprint of every material (fresh grape skins, crushed grape skins after fermentation, and wines) is related to cultivar characteristics. Thus, HPLC determination of the anthocyanin pattern of wines may be used to predict the grape cultivar from which wine was made.     

发酵石榴酒的色泽变化

研究了青皮甜、青皮酸、泰山红3个品种石榴汁在发酵过程中花色苷、色度、色调的变化及石榴汁、石榴酒色泽比较。结果表明:青皮甜、青皮酸、泰山红3品种石榴汁的最大扫描波长分别为513 nm、496 nm、514 nm。经过发酵,石榴汁花色苷、色度、色调都有一定程度的下降。泰山红石榴汁花色苷含量最高为82.26 mg/L,发酵结束时花色苷含量降至50.70 mg/L,3品种间花色苷含量具有显著性差异(P<0.01)。发酵结束时青皮酸石榴的色度值(未添加SO2为1.328、添加SO2为1.323)高于青皮甜和泰山红,与青皮甜、泰山红间有显著性差异(P<0.01)。青皮酸与泰山红色调值较高,2品种间具无显著差异(P>0.05),与青皮甜间具有显著性差异(P<0.01)。试验中添加50 mg/L的SO2,发酵过程中是否添加SO2两组的花色苷、色度、色调值无显著性差异(P>0.05)。将花色苷、色度、色调进行相关性分析得:花色苷与色度之间相关性不显著(Pearson相关系数为0.199,P=0.608>0.05),回归方程为y=0.0029x+1.0905;与色调之间相关性极显著(Pearson相关系数为0.885,P=0.002<0.01),回归方程为y=0.0153x+0.4687。     

Chromatic characteristics and anthocyanin profile of a micro-oxygenated red wine after oak or bottle maturation

Micro-oxygenation (MOX) was applied to a red wine for 5 months following the end of alcoholic fermentation and then both a non-oxygenated control wine and the micro-oxygenated wine were matured in oak barrels or bottles. The concentration of anthocyanin and anthocyanin-derived compounds and the chromatic characteristics of the control and micro-oxygenated wines after the maturation period were studied. Anthocyanin and anthocyanin-derived compounds composition were determined by liquid chromatography-mass spectrometry; and, together with monomeric anthocyanins, compounds including direct anthocyanin-flavanol adducts, ethyl-linked anthocyanin-flavanol compounds, and pyranoanthocyanins were identified. The results showed that the improvements in the chromatic characteristics obtained by applying the MOX technique to Monastrell wines were maintained after an aging period in bottle or barrel. The color intensity of wines increased during maturation in oak barrels, whereas the color of the bottled wines decreased, although MOX wines always showed higher color intensity than the respective control wines. Bottled wines also showed a higher increase in tint and a lower quantity of compounds resistant to SO₂ discoloration than oak matured wines, indicating that the formation of these compounds is favored by the oxidative conditions in oak barrels.