Effects of pulsed electric fields on the extraction of phenolic compounds during the fermentation of must of Tempranillo grapes

The effects of a pre-treatment of the grape skin with electric field treatments (PEF) at 5 and 10 kV/cm on the evolution of colour, anthocyanin and index of total polyphenols during the Tempranillo grape vinification and on the wine characteristics after fermentation have been investigated.Results showed that the permeabilization of the grape skin by application of a PEF treatment at room temperature caused an increment of the colour intensity, anthocyanin content and of total polyphenolic index with respect to the control during all the vinification process. Generally along the maceration process the values of these three parameters increased when the electric field strength raised from 5 to 10 kV/cm.Colour intensity and anthocyanin content of the wine significantly increased when the PEF treatment was applied at 10 kV/cm. However, the total phenolic index increased considerably with the application of a PEF treatment at 5 kV/cm. A further increment on the electric field strength did not appreciably augment this attribute. PEF did not affect the ratio between the components of the red wine colour (tint and yellow, red and blue components) and other wine characteristics such as alcohol content, total acidity, pH, reducing sugar concentration and volatile acidity.These results indicate that the PEF treatment previous to the maceration step in the winemaking process of the red wine can contribute to reduce the duration of the maceration during vinification or to increase the quantity of these attributes in the final wine.

Industrial relevance

This study investigates the effect of the application of a PEF pre-treatment of the grape skin on the evolution of colour, anthocyanin and index of total polyphenols during the Tempranillo grape vinification. Results obtained indicate that the application of a PEF treatment preceding the maceration step in the winemaking process of red wine could contribute to reduce the duration of the maceration during vinification or to increase the quantity of these parameters in the final wine. Latter effect could be of interest in grapes poor in polyphenols.     

Application of pulsed electric fields for improving the maceration process during vinification of red wine: influence of grape variety

The effect of the application of pulsed electric fields (PEF) treatments (2, 5 and 10 kV/cm) to the grape skin on the evolution of colour intensity, anthocyanins and index of total polyphenols along the vinification process of three grape varieties (Garnacha, Mazuelo and Graciano) has been investigated. It has been demonstrated that the ability of PEF to permeabilize cellular tissues is an effective treatment to improve the extraction of phenolic compounds. The influence of the intensity of the PEF treatment on colour intensity, anthocyanins and index of total polyphenols depended on the grape variety investigated. As compared with the control, the application of a PEF treatment was more effective in Mazuelo than in Garnacha and Graciano varieties. Increasing the electric field strength from 2 to 10 kV/cm led to a significant increment in treatment efficiency in Mazuelo but not in Garnacha and Graciano. The low energy consumption for cell permeabilization of grape skins (0.4–6.7 kJ/kg) and the short processing time required are key advantages of PEF technology to reduce the duration of the maceration during vinification or to increase the quantity of phenolic compounds in the final wine.     

赤霞珠和梅鹿辄干红葡萄酒的香气分析

本文以王朝赤霞珠、梅鹿辄两种干红葡萄酒为研究对象,利用液液萃取法提取香气成分,结合气相色谱-质谱联用技术对其进行分析,两种干红葡萄酒中共检出77种香气组分,根据计算机检索定性并利用面积归一化法对组分进行定量,鉴定出70种香气组分。     

Evaluation of phenolic extraction during fermentation of red grapes treated by a continuous pulsed electric fields process at pilot-plant scale

The feasibility of processing red grapes by pulsed electric fields (PEF) at pilot-plant scale to improve the extraction of anthocyanins and phenols during the maceration-fermentation step of the winemaking process has been investigated. With this general purpose a colinear continuous treatment chamber was developed. The influence of field strength (2, 5 and 7 kV/cm) and grape variety (Cabernet Sauvignon, Syrah and Merlot) in the extraction kinetics was studied. Extraction curves were described by an exponential equation that permits to estimate the extraction rate (k) and the maximum extraction yield (Y_max). An increment of the electric field from 2 to 7 kV/cm increased the extraction rate of anthocyanins and total phenols for the three varieties investigated. The increment of Y_max due to the application of PEF was more remarkable in Cabernet Sauvignon than in Merlot and Syrah. The continuous PEF system presented in this work constitutes an important step for the application of PEF technology at commercial scale.     

Effect of a pulsed electric field treatment on the anthocyanins composition and other quality parameters of Cabernet Sauvignon freshly fermented model wines obtained after different maceration times

The influence of the application of a pulsed electric field (PEF) treatment (5 kV/cm, 2.1 kJ/kg) to the grape pomace on different quality parameters and anthocyanins content of Cabernet Sauvignon wines obtained after different maceration times (48, 72, 96 and 248 h) has been investigated.Regardless of the maceration time, the application of a PEF treatment led to freshly fermented model wines that were richer in colour intensity, total polyphenols index (TPI), tannins and showed better visual characteristics. It was observed that the concentration of anthocyanins compounds in the freshly fermented model wines obtained from PEF-treated pomace was higher, as compared to the control wine. The HPLC anthocyanic profiles of freshly fermented model wines obtained from PEF-treated pomace were similar to those of control wine indicating that the permeabilization of the cell membranes of pomace did not produce a selective effect on any anthocyanin. Malvidin-3-glucoside and Malvidin-3-glucoside acetate were the predominant anthocyanins in both control and PEF wine.According to the results obtained in this investigation the application of a PEF treatment permitted to reduce the maceration time during vinification of Cabernet Sauvignon grapes from 268 to 72 h.     

Evolution of polyphenols in red wines from Vitis vinifera L. during aging in the bottle

The evolution of anthocyanins and pyranoanthocyanins (as measured by high-performance liquid chromatography) in young red wines from Vitis vinifera L. cv Tempranillo, Graciano and Cabernet Sauvignon (vintage 2000) from Navarra (Spain) was studied during 26 months of aging in the bottle. For the anthocyanin pigments of grape origin, a progressive decrease in their concentration, corresponding to first-order kinetics, was observed during this period. Independently of the anthocyanin structure studied, grape anthocyanins in Tempranillo wine presented twofold slower kinetics than those in Graciano and Cabernet Sauvignon wines, which exhibited a very similar disappearance rate. Acylated anthocyanins presented a slightly higher disappearance rate than the nonacylated ones, indicating the possible hydrolysis of the former into the latter forms. However, no distinction was observed in the kinetics of the different anthocyanidin forms (delphinidins, petunidins, peonidins and malvidins). These results indicate that during aging under nonoxidative conditions (bottle), the chemical reactivity of grape anthocyanins in wine is influenced by the grape variety, a factor that imposes over the stability associated with the chemical structure of each anthocyanin form. In relation to the evolution of pyranoanthocyanins, anthocyanin–pyruvic acid adducts presented a similar or lower disappearance rate than their corresponding anthocyanin precursors during the first months of aging in the bottle, while anthocyanin–vinylphenol and anthocyanin–vinylflavanol adducts did not exhibit significant variations during the whole period studied.     

赤霞珠、蛇龙珠和玫瑰香葡萄酒芳香性成分的差异性研究

芳香类物质种类及含量的差异是决定葡萄酒风味的重要因素。本文对赤霞珠、蛇龙珠和玫瑰香葡萄酒的芳香性成分进行探讨分析。结果表明,3种葡萄酒中3-甲基-1-丁醇的含量最高,相对含量分别为20.61%、21.00%和15.54%;次之为丁二酸单乙酯,含量分别为17.90%、8.94%和16.55%;再次为乳酸乙酯,含量分别为12.36%、17.01%和12.06%。赤霞珠干红葡萄酒中特有的检出成分为乙酸异戊酯和丙酸;玫瑰香葡萄酒中特有的检出成分为3-乙氧基丙醇。蛇龙珠葡萄酒中没有检出1-丁醇、4-酮基-戊酸乙酯和癸酸乙酯,赤霞珠和玫瑰香葡萄酒中均有上述成分;玫瑰香葡萄酒中未检测到(顺)3-己烯-1-醇和糠醇。     

赤霞珠干红葡萄酒在不同子产区香气特征的差异

以宁夏贺兰山东麓5个不同子产区石嘴山市、银川市贺兰县、西夏区、永宁县和吴忠市红寺堡区的17款赤霞珠干红葡萄酒为研究对象,采用顶空固相微萃取与气相色谱-质谱联用法(headpace solid-phase microextraction and gas chromatography-mass spectrometry,HS-SPME-GC-MS),分析酒样的香气物质以及气味活性值(odor activity value,OAV),确定具有感官贡献的香气物质,结合主成分分析研究5个子产区之间的相关性。结果表明,酒样香气物质在组成上具有一致性,主要是醇类和酯类物质。此外,大马士酮香气贡献最为突出,使得宁夏贺兰山东麓赤霞珠干红葡萄酒香气主要具有花香和果香特征。主成分分析结果表明,利用植物香指数和脂香指数可区分不同子产区的香气特征,辛酸甲酯、乙酸苯乙酯、月桂酸乙酯;2,4-二叔丁基苯酚;苯乙醇;大马士酮和癸酸乙酯;乙酸异戊酯分别对石嘴山市、银川市贺兰县、西夏区、永宁县和吴忠市红寺堡区葡萄酒香气有重要贡献。聚类结果表明,石嘴山市和银川市西夏区葡萄酒香气更为接近。     

河西地区不同产地赤霞珠干红葡萄酒挥发性成分分析

以甘肃河西走廊产区5个不同产地葡萄园的赤霞珠葡萄为原料,分别发酵酿造干红葡萄酒,并对样品进行挥发性成分分析,共检测出107种物质,其中主要成分有58种,包括醇类物质19种,酯类物质18种、酸类物质5种、羰基类9种以及其他7种。对比不同产地赤霞珠干红酒发现其挥发性成分在种类和含量均有差异,并表现为各自特有的品质特性。     

Effect of the modifier (Graciano vs. Cabernet Sauvignon) on blends of Tempranillo wine during ageing in the bottle. I. Anthocyanins, pyranoanthocyanins and non-anthocyanin phenolics

The effect of Graciano (GRA) (Spanish valuable variety of limited production) vs. Cabernet Sauvignon (CS) (world wide known French variety) wines on the anthocyanin, pyranoanthocyanin and non-anthocyanin phenolic composition of wines from Tempranillo (TEM-base wine) (largely cultivated Spanish variety) was studied in wine blends prepared with 25% and 10% (v/v) of each modifier after 4, 6, 9, 16.5 and 23 months of ageing in the bottle. Blending mainly resulted in a higher concentration of peonidin anthocyanins for the TEM-GRA blends, of acetyl-glucoside anthocyanins and anthocyanin-pyruvic acid adducts for the TEM-CS blends, and of flavanols for the blends with both GRA and CS varieties, giving rise to wines with a more balanced anthocyanin/flavanol ratio. Blending also enhanced the changes expected to occur in the phenolic compounds during ageing in the bottle. Particularly, anthocyanins and flavanols in the blends disappeared faster than in the base wine, and this was more pronounced for the 75:25 than for the 90:10 blends. These effects were similar for both modifier wines, independent of the specific changes produced in the anthocyanin profile of the base wine, but coincided with the similar optimization of the anthocyanin/flavanol ratio provided by both Graciano and Cabernet Sauvignon wines.     

中国5个产区赤霞珠干红葡萄酒挥发性香气成分差异研究

为研究不同产区赤霞珠干红葡萄酒挥发性香气成分的差异。以我国宁夏芦花台、云南德钦、甘肃武威、河北昌黎和新疆石河子5个产区的赤霞珠干红葡萄酒为研究对象,通过二氯甲烷液-液萃取法提取香气成分和气相色谱-质谱串联检测分析,共鉴定出30种香气成分,其中主要包括醇类12种、酯类10种、有机酸6种。占主体的9种挥发性香气成分是:3-甲基丁醇、丁二酸单乙酯、2-甲基丁醇、苯乙醇、2-羟基丙酸乙酯、乙酸乙酯、2,3-丁二醇、乙酸、2-甲基丙醇。结果表明,不同产区的赤霞珠干红葡萄酒香气成分种类基本相近,但各香气成分相对含量有显著差异。由于目前干红葡萄酒的酿制方法和技术基本接近,充分了解这些香气物质在葡萄酒不同产地间的差异及其与感官上的对应关系,有助于提高我国各产区葡萄酒品质以及挖掘地方特色干红葡萄酒的优势。     

Evolution of polyphenols in red wines from Vitis vinifera L. during aging in the bottle

The evolution of non-anthocyanin phenolic compounds (as measured by high-performance liquid chromatography) in young red wines from Vitis vinifera L. cv Tempranillo, Graciano and Cabernet Sauvignon (vintage 2000) from Navarra (Spain) was studied during 26 months of aging in the bottle. Hydroxybenzoic acids and derivatives (gallic, protocatechuic, vanillic and syringic acids, and methyl and ethyl gallates), hydroxycinnamic acids and derivatives (trans-caftaric, cutaric, caffeic and p-coumaric acids, and hexose esters of trans-p-coumaric acid), stilbenes (trans- and cis-resveratrol-3-O-glucosides, and trans- and cis-resveratrol), phenolic alcohols and other related compounds (tyrosol and tryptophol), flavanols [procyanidins B1 and B2, (+)-catechin and (–)-epicatechin] and flavonols (myricetin-3-O-glucoside, quercetin-3-O-galactoside and quercetin-3-O-glucuronide, kaempherol-3-O-glucoside, myricetin and quercetin) presented different evolution patterns during aging, in some cases also being different depending on the grape variety studied. The changes that occurred during aging in the bottle were the decrease of the concentration of trans-caftaric and cutaric acids accompanied by an increase of trans-caffeic acid and, especially of trans-p-coumaric acid. The greater increase of trans-p-coumaric acid was also associated with the disappearance of p-coumaroyl-acylated anthocyanins that occurs during aging in the bottle. Flavanols registered a major decrease, with the disappearance rate being greater for the dimeric procyanidins than for the monomeric flavanols, and the order of the disappearance rate by variety was as follows: Tempranillo相似文献   

避雨栽培对赤霞珠葡萄酒非花色苷酚类的影响

研究避雨栽培对葡萄酒非花色苷酚类的影响,为酿酒葡萄避雨栽培技术的实施提供理论依据。采取简单避雨方式,以赤霞珠(Vitis vinifera L cv.Cabernet Sauvignon)葡萄为材料,在转色后进行避雨处理,以露地栽培为对照;葡萄收获后采用传统工艺酿制干红葡萄酒,测定其基本理化指标及非花色苷酚的种类和含量,获得如下结果:(1)避雨栽培降低了赤霞珠葡萄酒总酸、总酚和单宁含量,但差异不显著。(2)避雨栽培对一些单体非花色苷酚类含量存在显著影响,显著降低了黄烷醇类总量,但对黄酮醇和类黄酮酚总量无显著影响;极显著降低了苯甲酸、芪类和非类黄酮酚,增加了肉桂酸类含量。(3)对葡萄酒非花色苷酚类物质种类无影响,降低了非花色苷酚类总量但差异不显著。因此,在赤霞珠葡萄转色期采取避雨措施,对干红葡萄酒非花色苷酚类的影响不显著。     

Freezing of potato tissue pre-treated by pulsed electric fields

The effects of pulsed electric fields (PEF) pre-treatment on the freezing, freeze-drying and rehydration behavior of potato were studied. Potato samples (26 mm diameter, 10 mm high) were treated by PEF (400 V/cm) for various durations between 10⁻⁴ and 0.3 s. The degree of tissue damage was quantified by the change in electrical conductivity. PEF treated and untreated samples were either frozen in an air-blast freezer with air at −35 °C and 2 m/s velocity or freeze-dried at 0 °C and 0.04 mbar pressure and then rehydrated in water at 25 °C. The freezing times for PEF pre-treated samples reduced as the PEF-induced tissue damage increased. Scanning electron microscope images of the air-blast frozen and then freeze-dried samples showed increased deformation of cells and larger intercellular spaces (frozen samples only) for the PEF pre-treated samples. However, PEF pre-treatment improved the rate of freeze-drying and improved the quality and rehydration of the samples.     

Changes in viscosity and pectolytic enzymes of tomato and strawberry juices processed by high-intensity pulsed electric fields

The effects pulse frequency (50–250 Hz), pulse width (1.0–7.0 μs) and polarity (monopolar or bipolar) of high-intensity pulsed electric field treatments (35 kV cm⁻¹ and 1000 μs) on viscosity and the pectin methylesterase (PME) and polygalacturonase (PG) activities were evaluated using a response surface methodology. Second-order expressions were accurate enough to fit experimental results. Tomato juice apparent viscosity increased within the range of the assayed conditions, achieving the highest values at 250 Hz and 7.0 μs in bipolar mode. At the same conditions the lowest residual PME (RA_PME = 10%) and PG (RA_PG = 45%) activities were observed in the juice. Apparent viscosity of strawberry juices slightly rose when frequencies higher than 100 Hz and 1-μs monopolar pulses were applied to the juice. Treatments causing the greatest increase in strawberry juice apparent viscosity also led to the lowest RA_PME (10%) and RA_PG (75%) values. In contrast, viscosity loss was promoted under the rest of assayed HIPEF conditions despite the low RA_PME values (<20%) achieved. Moreover, RA_PG did not decrease below 75% throughout the range of studied conditions.     

Inactivation of soybean lipoxygenase in soymilk by pulsed electric fields

The inactivation of soybean lipoxygenase by pulsed electric fields (PEF) was studied. Effects of PEF parameters (treatment time, pulse strength, pulse frequency and pulse width) were evaluated. Soymilk was exposed to pulsed strengths from 20 to 42 kV/cm for up to 1036 μs treatment time in square wave pulse of bipolar mode. Moreover, pulse frequency (100–600 Hz) and pulse width (1–5 μs) was also tested at constant pulsed treatment time of 345 μs and strength of 30 kV/cm. Residual activity of soybean lipoxygenase decreased with the increase of treatment time, pulse strength, pulse frequency and pulse width. The maximum inactivation of soybean lipoxygenase by PEF achieved 88% at 42 kV/cm for 1036 μs with 400 Hz of pulse frequency and 2 μs of pulse width at 25 °C. Inactivation of soybean lipoxygenase by pulsed electric fields was modeled using several kinetic models. Weibull distribution function was most suitable model describing the inactivation of soybean LOX as a function of pulsed electric fields process parameters. Moreover, reduction of soybean LOX activity related to the electric field strength could be well described by the Fermi model.     

Comparative study of phenolic compounds in Cabernet Sauvignon wines made in traditional and Ganimede fermenters

Chemical profiles of anthocyanin and non-anthocyanin phenolics of Cabernet Sauvignon wine made by two different winemaking techniques (traditional vinification and Ganimede method) were determined by high performance liquid chromatography–mass spectrometry (HPLC–MS). Particularly, effect of extraction on and subsequent stability of the phenolic compounds from the end of fermentation to bottling were investigated. The results showed that the total anthocyanin content was higher in the young wines produced in the Ganimede fermenter. The anthocyanin contents in these wines subsequently decreased significantly after two years of ageing. By contrast, the traditional vinification was slightly better than the Ganimede to yield the non-anthocyanin phenolics. This indicates that the Ganimede fermenter might be suitable for the production of brightly coloured red wines for early consumption, which could save time and labour cost for industrial production of highquality wines.     

Volatile composition and aromatic attributes of wine made with Vitisvinifera L.cv Cabernet Sauvignon grapes in the Xinjiang region of China: effect of different commercial yeasts

The Xinjiang region is a major grape- and wine-production area in China, but the region’s notably high temperatures in the summer and year-round intense sun exposure play negative roles in the aroma, complexity, and elegance of Cabernet Sauvignon wine. In this study, Cabernet Sauvignon grapes harvested in this region were fermented on an industrial scale using four commercial yeast strains (L2323, D254, RVA, and CECA) and spontaneous yeast (NF). The results showed that a total of 123 volatile compounds were detected and 15 volatile compounds significantly contributed their flavor notes to the wine’s overall aroma. The use of RVA and CECA strains resulted in wine with higher concentrations of higher alcohols, terpenes and norisoprenoids. However, the D254-fermented wine showed high level of esters and carbonyl compounds. Wine fermented with the L2323 and D254 strain possessed a stronger fruity aroma, whereas the RVA strain enhanced the herbaceous, chemical, and fatty aromas in wine. Principal component analysis revealed that a significant aromatic feature difference was observed in these wines after alcoholic and malolactic fermentation. The use of different commercial yeast strains altered the aromatic profile of Cabernet Sauvignon wine.