The maceration process during winemaking extraction of anthocyanins from grape skins into wine

The rate of anthocyanin extraction from skins of Monastrell grapes into wine during the maceration process has been studied by following anthocyanin accumulation in wine and its decrease in crushed skins. The most important changes occurred during the first 7 days of maceration; the following 7 days saw very little variation in the levels of the anthocyanins found in the wine or the crushed skins. The anthocyanin profile of the wines was quite different from that of the grape skins, whereas the crushed grape skins had a profile very similar to the profile of the grape skins at the time of harvest. Any differences in the proportions of the different anthocyanins found in Monastrell grapes and wines cannot therefore be attributed to different rates of extraction for each of the anthocyanins during winemaking. Other explanations, such as degradation or yeast cell wall adsorption, must be sought.     

Anthocyanin profiles of major red grape (Vitis vinifera L.) varieties cultivated in Greece and their relationship with in vitro antioxidant characteristics

A range of fourty‐six red grape (Vitis vinifera spp.) samples, originating from six widely cultivated varieties and covering major parts of the Hellenic vineyard, were assayed for their content in six principal anthocyanin pigments. Representative in vitro antioxidant parameters were also determined, including antiradical activity (A_AR), reducing power (P_R) and hydroxyl free radical scavenging activity (SA_HFR). Quantitative determination using high performance liquid chromatography showed that the prevalent pigment was malvidin 3‐O‐glucoside (average content 82.53 mg per 100 g fresh berry weight), followed by its coumarate derivative (29.26 mg per 100 g), paeonidin 3‐O‐glucoside (10.84 mg per 100 g), petunidin 3‐O‐glucoside (7.80 mg per 100 g) cyanidin 3‐O‐glucoside (5.67 mg per 100 g) and delphinidin 3‐O‐glucoside (1.28 mg per 100 g). The richest variety was Syrah, with total average anthocyanin content of 186.02 mg per 100 g, whereas the Hellenic native variety Xinomavro had the lowest average anthocyanin level (38.70 mg per 100 g). The establishment of correlations of individual and total anthocyanin contents with the values from the antioxidant test was accomplished with linear regression. The links of total anthocyanins were significant with all antioxidant parameters (P < 0.001), but more importantly with SA_HFR (R² = 0.740). Malvidin 3‐O‐glucoside content had the higher correlation with SA_HFR compared with all other anthocyanins (R² = 0.698, P < 0.001).     

Hepatic uptake of grape anthocyanins and the role of bilitranslocase

Anthocyanins are water-soluble compounds that pigment berries, grapes and vegetables. Their flavonoid backbone endows them with oxygen radical scavenging activity. Thus, they could play a role in protecting the human organism from various degenerative and proliferative diseases, that are currently believed to result from an oxygen radical-mediated disruption of cellular components. Their great potential as functional food ingredients is, however, restricted by the incomplete knowledge of their bioavailability. In order to contribute to filling this gap, we looked for their presence in the liver, after administration of a solution of pure grape anthocyanins into the stomach of anaesthetised rats. We found that the liver contained both malvidin 3-glucoside and its p-coumarate ester, the main and the minor component of the mixture, respectively. Isolated, cultured liver cells were also found to be permeable to malvidin 3-glucoside and bilitranslocase was identified as the carrier protein involved, by using two different specific antibodies.     

川西北干旱河谷地区赤霞珠葡萄果实花色苷的积累

花色苷是葡萄果实主要呈色物质,其积累受环境因素的影响.本研究以川西北干旱河谷地区的赤霞珠葡萄果实为试材,采用高效液相色谱-质谱联用以及荧光实时定量PCR技术分析了果实成熟过程中花色苷的组成与含量及部分关键酶基因的表达.结果表明,从果实完全转色至随后的3或4周内,是花色苷积累的高峰期;酰化和非酰化花色苷的相对比例及甲基化和非甲基化花色苷的相对比例不随成熟进程或年份而变化,但花翠素类与花青素类花色苷的相对比例受年份影响较大,降雨量是最主要的影响因子,它可能通过影响花色苷积累高峰期果实类黄酮代谢中F3'H和F3'5'H基因的表达而影响碳的分支流向.     

On‐the‐go sensing of grape berry anthocyanins during commercial harvest: development and prospects

Background and Aims: The development and adoption of Precision Viticulture approaches to grape and wine production have been hindered by the lack of a commercially available sensor for on‐the‐go sensing of fruit quality during harvest. In this work, we sought to deploy the Multiplex®, a fluorescence‐based non‐contact hand‐held optical sensor on a harvester, for on‐the‐go sensing of berry anthocyanins during the South Australian vintage of 2010. Methods and Results: Measurements made of anthocyanin concentrations in the laboratory using the Multiplex showed high correlation (R² > 0.9) with those made on the same grapes using the standard spectrophotogrametric method. When used in hand‐held mode in the field, data collected using Multiplex demonstrated a similar spatial structure to that observed in other data layers (remotely sensed vigour, yield, elevation). Similarly, when deployed on a harvester as an on‐the‐go sensor, data obtained using Multiplex exhibited the expected spatial structure. Conclusions: Meaningful measurement of grape berry anthocyanins on‐the‐go during harvest is feasible using Multiplex. Significance of the Study: This is the first time that berry colour has been sensed on‐the‐go during harvest. The work therefore paves the way for a greater focus on attributes of fruit quality in the delineation of vineyard management zones and implementation of Precision Viticulture.     

Substantial water uptake into detached grape berries occurs through the stem surface

Background and Aims: Water uptake through the stem surface contributes to total water uptake of submerged grape berries (Vitis vinifera L.). The objective was to identify the site of this uptake. Methods and Results: Uptake of water and a fluorescent dye was studied using a single berry + stem system. To identify the site of water uptake, the cut end of the stem and selected regions of the stem surface were coated with a silicone sealant. Water uptake was determined gravimetrically. After immersing in dye solution, the stem and the receptacle region of the stem/berry junction fluoresced, but the exocarp did not. Fluorescence of vascular bundles in stem and berry indicated that the dye taken up was transported into the berry. Selective coating of the various stem parts revealed that at steady state (96 to 144 h), the stem/berry junction (0.11 ± 0.04 mg/h), receptacle (0.09 ± 0.03 mg/h) and the remaining stem surface (0.08 ± 0.03 mg/h) contributed approximately equally to total water uptake in the whole stem region (0.24 ± 0.05 mg/h), which in turn accounted for 55% of uptake of a berry + stem (0.43 ± 0.05 mg/h). Conclusions: Stem/berry junction, and periderms of abscission zones and lenticels represent regions of preferential water uptake into detached grape berries. Significance of the Study: Extrapolating from the single berry system to an intact bunch on a grapevine demonstrates that water uptake through the stem tissues inside a compact bunch may contribute to berry cracking under vineyard conditions.     

Effect of energy density and citric acid concentration on anthocyanins yield and solution temperature of grape peel in microwave-assisted extraction process

In order to verify the sensitivity of anthocyanins (Acys) yield of grape peel to the energy density (microwave power for a given unit of volume) and citric acid concentration in microwave-assisted extraction (MAE) process, the effect of energy density and citric acid concentration in MAE process were investigated. The results indicated that, Acys yield was more sensitive to energy density than to microwave power. The correlation between Acys yield and energy density follows well Gaussian function, suggested by higher R squares (R² > 0.9399). Exponential decay model can well describe the correlation between Acys yield and citric acid concentration, or between solution temperature rise and energy density. The solution temperature was a linear function of citric acid concentration and extraction time. Energy density was the most significant factor affecting the Acys yield, followed by citric acid concentration, ratio of liquid to solid and extraction time (p < 0.05).     

Effects of exogenous abscisic acid on antioxidant capacities,anthocyanins, and flavonol contents of muscadine grape (Vitis rotundifolia) skins

The objective of this study was to evaluate the effect of exogenous abscisic acid (ABA) on the antioxidant capacity and phenolic content of muscadine grape skins (cvs. Noble and Alachua). ABA was applied on grapes during and after veraison. Average berry weight, total soluble solids (⁰Brix) and pH of the juice from both cultivars were not affected by the ABA treatment. Antioxidant capacity was enhanced by 38% and 18% in treated Noble at the first and second sampling, respectively. High performance liquid chromatography analysis revealed a significant increase in individual anthocyanins in treated Noble grapes at both sampling times. However, increase in the content of ellagic acid, myricetin, quercetin and kaempferol was observed at first sampling only. No effects of ABA treatment were seen in Alachua grapes. Our results indicate that exogenous application of ABA enhances the antioxidant capacity, anthocyanins and phenolic content of muscadine grapes but these effects may vary depending upon the cultivar.     

Phenolic fortification of yogurt using grape and callus extracts

In this study, acidified ethanol extracts of four different grape varieties (Cabernet sauvignon, Chardonnay, Shyrah, and Merlot) and grape callus were supplemented into yogurt as functional ingredients. The total phenolic substances, total anthocyanin content, and antioxidant activity of the yogurts were measured using chemical analyses. Yogurts inoculated with red grape and callus extracts displayed high phenolic - anthocyanin content and thus exhibited higher antioxidant power compared to yogurts containing chardonnay extracts and control samples. The storage time significantly affected the free radical scavenging capacity of the yogurts. The yogurts supplied with grape callus extract displayed the greatest antioxidant power on the first day of storage compared to all the assayed samples. The Gas Chromatography (GC) analysis revealed the presence of at least 10 individual bioactive phenolic compounds in the callus yogurt. The results obtained from this investigation shows that grape callus culture has a potential to be used as a food supplement to play a role in reducing the risk of developing chronic diseases such as cancer and cardiovascular disease.     

Rapid and non‐destructive method to assess in the vineyard grape berry anthocyanins under different seasonal and water conditions*

Background and Aims: Monitoring of anthocyanins (Anth) in winegrape (Vitis vinifera L.) is fundamental for the production of top‐quality red wines. This work was aimed at testing a new fluorescence‐based sensor for Anth detection in the vineyard. Significance of the Study: The present study showed a new important innovative technology for viticulture. The sensor evaluation of the large spatial and temporal heterogeneity in Anth accumulation can be useful as support parameter in the harvest date decision or for vineyard zoning of phenolic maturity. Methods and Results: Anth in grape (cv. Aleatico) bunches attached to the vine were monitored non‐destructively in the field using a fluorescence‐based sensor during the 2008 and 2009 seasons and under different water regimes. The ANTH_RG index = log(far‐red‐fluorescence_R/far‐red‐fluorescence_G), with fluorescence signals excited with red (R) and green (G) light, was inversely correlated through an exponential function (r² = 0.875) to the Anth concentration derived from the HPLC analysis of berry skin extracts. ANTH_RG was effective in detecting the earlier ripening process in 2009 with respect to 2008 and differences in the Anth accumulation between seasons and in relation to different water regimes. Water deficit imposed in 2009 enhanced Anth concentration in berries because of a reduction in berry size but also an increase of Anth biosynthesis. This effect was observed by both destructive and ANTH_RG non‐destructive measurements. Conclusions: Our results show that the employed fluorescence sensor represents a reliable, rapid and non‐invasive tool for monitoring and determining Anth accumulation in situ.     

葡萄籽提取物原花青素的研究概况及其在我国保健食品中的应用

葡萄籽提取物原花青素（GSPE）具有抗氧化、保护心血管、抗突变等生物活性，在食品、药品、化妆品等领域广泛应用。近年来已成为我国保健食品中常用的一种原料。为给在保健食品中的进一步研究应用提供参考，对GSPE的化学结构、提取分离、分析方法、生物活性、食用安全性等方面进行概述，并对其在我国保健食品中的保健功能分布、用量情况、质量标准等方面的情况以及存在问题进行了分析。     

Auxin treatment of pre‐veraison grape (Vitis vinifera L.) berries both delays ripening and increases the synchronicity of sugar accumulation

Background and Aims: Pre‐veraison auxin treatments can delay grape berry ripening, but there is little information about their effects on berry development and wine composition. The aim of this study was to further investigate these effects and explore the practical implications of delaying ripening. Methods and Results: Treatment of pre‐veraison Vitis vinifera L. cv. Shiraz berries with 1‐naphthaleneacetic acid (NAA) significantly delayed ripening as measured by the accumulation of total soluble solids (TSS) and anthocyanins. The onset of the post‐veraison phase of berry size increase was delayed in NAA‐treated fruit, but these fruit were significantly larger than Control fruit at harvest. NAA‐treatments significantly increased the synchronicity of berry sugar accumulation. GC‐MS analysis of wine headspace volatiles showed significant, but largely small, differences in the concentration of 19 compounds. No significant difference in sensory properties was found between replicate small‐scale wine lots made from Control and NAA‐treated fruit. Conclusions: Auxin treatment delayed berry ripening, increased the synchronicity of sugar accumulation between berries, increased berry size and changed the levels of some volatile compounds, but did not affect wine sensory properties. Significance of the Study: We propose that NAA sprays might be used to delay grape berry ripening and increase the synchronicity of sugar accumulation, and therefore ripening, without deleterious effects on wine quality. This may be useful in controlling winery intake and fruit composition.     

Development changes of anthocyanins in Vitis vinifera grapes grown in the Douro Valley and concentration in respective wines

Grapes of Touriga Nacional and Touriga Francesa red Vitis vinifera varieties have been sampled from two vineyard sites at different altitudes during three consecutive vintage years (1997, 1998 and 1999) in the Douro Valley. The total anthocyanidin monoglucosides (AMGs) detected by HPLC/DAD and the red colour of grape skin extracts were monitored during the last month of maturation. Microvinifications were performed with the grapes studied and the resulting Port wines were analysed. Malvidin 3‐glucoside and its acylated esters were the major AMGs irrespective of cultivar at harvest date. Vineyard altitude, together with other variables, was found to be an important factor contributing to the amount of anthocyanin compounds found in grapes of Touriga Nacional and Touriga Francesa. Overall, the climatic conditions observed at higher vineyard sites appeared to be advantageous, resulting in larger amounts of AMGs in grapes. The same outcome was obtained in the resulting wines, which showed higher levels of AMGs when made from grapes grown at higher altitude, especially for Touriga Francesa. © 2002 Society of Chemical Industry     

Electrochemical behaviour and antioxidant capacity of anthocyanins from Chilean red wine,grape and raspberry

The anthocyanin fractions were extracted from Cabernet Sauvignon red wine, skins of Vitis vinifera grapes and raspberry fruits (Rubus idaeus). In red wine extract, 16 anthocyanins were identified, malvidin-3-O-glucoside being the main anthocyanin, which comprised 53.6% of the total anthocyanin in grape extract. Raspberry extract contained mainly delphinidin-3-O-glucoside and cyanidin-3-O-glucoside. The antioxidant capacity of the extracts was assayed by electrochemical methods. Best resolution of the oxidation peaks for the extracts and diluted wine was obtained by pulse differential voltammetry. The wine diluted 20× presented values of P1 (443 mV) and P2 (676 mV) similar to those corresponding to wine extract, and to the anthocyanin malvidin-3-O-glucoside. The antioxidant capacity of anthocyanins in extracts of wine, grape skin and raspberry fruit was also determined by the Trolox equivalent antioxidant capacity (TEAC) method.     

Variety and storage time affect the compositional changes that occur in grape samples after frozen storage

Background and Aims: In viticultural and oenological research, grape samples are frequently stored frozen to overcome time and facility restraint. However, there is little knowledge on how freezing, variety and storage time affect the changes occurring in grape quality parameters. The aim of the paper was to evaluate these effects using cv. Cabernet Sauvignon (CS), Grenache (GA) and Tempranillo (TE) samples. Methods and Results: Quality parameters were assessed in fresh grapes and after 1, 3 and 6 months of frozen storage. Soluble solid concentration remained unchanged. Freezing decreased titratable and tartaric acidity. pH increased after 1 and 3 months of storage, but decreased after 6 months. Freezing increased malic acid concentration only in GA. Yeast assimilable nitrogen diminished with freezing time, with each variety behaving differently. A significant colour enhancement was found (EAnt, L*, C*), whereas degradative reactions for polyphenols occurred at any storage time for GA, and for all varieties after 6 months. Conclusions: Variety and storage time play a large role in the changes occurring in stored frozen grape samples. Not considering these factors may lead to misinterpretation of results obtained through subsequent use of these grapes. Significance of the Study: Specific correcting factors for each quality parameter, variety and storage time are needed when working with stored frozen samples.     

Physicochemical characteristics and functional properties of grape (Vitis vinifera L.) seeds protein

The amino acid composition, physicochemical and functional properties of grape (Vitis vinifera L.) seeds protein (GSP) were evaluated and compared with those of soybean protein isolate (SPI). Amino acid analyses of GSP revealed high levels of glutamic/glutamine, glycine and aspartic/asparagines. SDS‐PAGE analysis demonstrated that globulin was the major protein component in GSP, whose subunit molecular weights were mainly varied from 25.5 to 40.0 kDa. The isoelectric pH of GSP was found to be at the acidic pH of around 3.8. At all the pHs tested except pH 2.0, no significant changes of GSP secondary structure were observed. GSP exhibited beneficial functional properties such as preferable solubility and emulsifying activity, while the foaming properties and water holding capacity were relatively poor compared to SPI. It could then be employed to soup, sauce, beverage or meat product for improving nutritional and sensory quality of these foods at appropriate pHs.