The effect of Uncinula necator (powdery mildew) and Botrytis cinerea infection of grapes on the levels of haze-forming pathogenesis-related proteins in grape juice and wine

Powdery mildew on Chardonnay grapes resulted in increased levels of a grape thaumatin-like protein, VvTL2, in the free run juice compared to that from uninfected grapes. These increased levels persisted through winemaking and at the highest level of infection (> 30% of bunches infected) had a significant impact on the haziness in the wine following a heat test. Infection of Cabernet Sauvignon grapes (1–20% of bunches infected) did not affect the protein concentration of free run juice, and only traces of pathogenesis-related (PR) proteins remained detectable in the Cabernet Sauvignon wines from either infected or healthy grapes. In contrast, infection of Chardonnay or Semillon grapes by Botrytis cinerea in the vineyard resulted in decreased levels of all PR proteins in the free run juice and in a total protein extract from infected berries compared to that from uninfected grapes. Similar trends were observed when B. cinerea was grown in the laboratory on surface-sterilised berries or in filter-sterilised juice.     

The effect of mechanical harvesting and transport of grapes, and juice oxidation, on the protein stability of wines

The concentration of haze-forming protein was determined in wines made from Sauvignon Blanc grapes harvested by hand or machine and transported for up to 400 km. The effect of oxidation of juice from mechanically harvested fruit on the concentration of haze-forming proteins was also investigated. Wines made from mechanically harvested, long-distance transported fruit contained more heat-unstable protein, and required fining with twice as much bentonite to ensure heat stability as wines made from hand-picked fruit. Juice oxidation had little effect on protein content of the juice or of the wine made from it.     

Fungi and mycotoxins in vineyards and grape products

Many fungi may occur on grapes during growth in the vineyard, but the main concern from the viewpoint of mycotoxin contamination is the black Aspergilli, Aspergillus carbonarius and A. niger. These fungi are capable of producing ochratoxin A (OA) which may contaminate grapes and grape products such as wine, grape juice and dried vine fruit. Understanding the ecology and physiology of the black Aspergilli can provide tools for management of OA at all stages of grape production and processing. In the vineyard, careful management of cultivation, irrigation and pruning can assist in minimising the levels of black Aspergilli in the soil, which in turn, can minimise contamination of grapes by these fungi. Minimising damage to grapes on the vine by the use of open vine canopies, grape varieties with resistance to rain damage and by the management of insect pests and fungal diseases (e.g., mildew, Botrytis bunch rot) can reduce the incidence of Aspergillus rot in mature berries. The risk of OA in table grapes can be minimised by careful visual inspection to avoid damaged and discoloured berries. In wine, harvesting grapes with minimal damage, rapid processing and good sanitation practices in the winery assist in minimising OA. During vinification, pressing of grapes, and clarification steps which remove grape solids, grape proteins and spent yeast can also remove a significant proportion of OA. For dried vine fruit production, avoiding berry damage, rapid drying, and final cleaning and sorting to remove dark berries can reduce overall OA levels in finished products.     

Evaluation of pathogenesis-related protein content and protein instability of seven white grape (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.) clones from Casablanca Valley,Chile

Thaumatin-like proteins and chitinases are the main pathogenesis-related (PR) proteins found in grapes, grape juice and wine and are responsible for protein haze formation in bottled white wine during storage and transport. We have studied the effect of the content of both thaumatin-like proteins and chitinases on protein instability of Sauvignon blanc (clones 1, 107 and 242) and Chardonnay (clones 4, 5, 75 and Mendoza) grape juices from both a warm and a cold production zone in the Casablanca Valley, Chile. The PR proteins were identified and quantified by reversed-phase liquid chromatography (RP-HPLC). Protein instability was determined using a heat test and was expressed in nephelometric turbidity units (NTUs). Thaumatin-like (TL) proteins were identified as the major PR proteins present in all grape juices studied. Three TL proteins were identified and named Vitis vinifera thaumatin-like proteins 1, 2 and 3 (VVTL1, VVTL2 and VVTL3). Chitinase A (ChitA) was identified in the Sauvignon blanc and Chardonnay grape juices, and chitinase B (ChitB) was found only in Chardonnay grape juices. Significant differences in the protein content and in the type of protein were observed between grapes from different production zones and between grapes of different varieties, respectively.     

Effects of the rootstock Ramsey (Vitis champini) on ion and organic acid composition of grapes and wine, and on wine spectral characteristics

The influence of Ramsey, used as rootstock of the scion cvs Muscat Gordo Blanco (syn. Muscat of Alexandria), Shiraz (syn. Syrah), Riesling, Cabernet Sauvignon and Chardonnay, on the characteristics of the grape berries and of wine made from them was investigated, comparing ‘own-rooted’ and ‘grafted’, and comparing wine fermented as juice (without skins) and must (juice and skins). The study involved the partitioning of K+ within berries, changes in juice K+, malic and tartaric acid through fermentation, wine inorganic ion and organic acid composition, and wine spectral characteristics. K+ concentration was higher in berries from grafted than from own-rooted for all varieties except Chardonnay, and highest for grafted Shiraz. It was higher in skin than in pulp and seeds. In the pulp, it was highest for grafted Shiraz. K+ concentrations in all ferments using must (i.e. juice plus skins) increased during the initial two days after crushing, with the increase reflecting extraction from skins, being greatest for Shiraz and Muscat Gordo Blanco. Tartaric acid concentration in must also increased during the initial two days after crushing and then decreased. Malic acid concentration was higher in juice of Ramsey-grafted than own-rooted vines, especially for Shiraz; concentrations did not change markedly during the initial 12 days of fermentation, except where malo-lactic fermentation occurred. Wine made from grapes of grafted contained significantly less tartaric and more malic acid than that made from own-rooted for all varieties and for both fermentation types, with the exception of tartaric acid in wine of Muscat Gordo Blanco fermented as must. Wine made from juice had significantly higher tartaric acid and lower malic acid than that made from must for all varieties except for tartaric acid in wine from grafted Shiraz and malic acid in own-rooted Chardonnay. Wine had a smaller tartaric acid/malic acid ratio when made from must. Wine pH was positively correlated with K+ but negatively with tartaric acid and with the tartaric acid to malic acid ratio. Overall, Shiraz wine contained highest Cl?, Na+ and K+ concentrations. Red wines obtained from grafted had higher colour hue, especially those from Shiraz. Wines made from fruit borne on own-rooted Cabernet Sauvignon had the highest concentration of total anthocyanins, ionised anthocyanins and total phenolics.     

Anthocyanin composition and anthocyanin pathway gene expression in grapevine sports differing in berry skin colour

The synthesis of anthocyanins was investigated in six grapevine sports with altered skin colour. Cabernet Sauvignon and Shiraz grapes contained anthocyanin monoglucosides as well as acetylated and coumarylated derivatives, predominantly of malvidin, whereas Pinot Noir grapes contained only anthocyanin monoglucosides. Fruit of some sports arising from varieties with black berries either lacked anthocyanins or had much lower levels than their progenitors. A bud sport of Cabernet Sauvignon (Bronze Cabernet) exhibited a 90% reduction in anthocyanin levels, but an anthocyanin composition similar to that of the normal Cabernet Sauvignon fruit. The fruit of a white-coloured bud sport of Bronze Cabernet did not contain anthocyanins. Coloured berries of sports originating on varieties with white-skinned berries also had lower levels of anthocyanins than black grapes, but like Pinot Noir contained very low levels of acylated anthocyanins. The berries of these sports also varied in the proportions of the different types of 3-monoglucosides they contained. The results suggest that control of 3-monoglucoside synthesis and modification vary in the sports. The expression of six genes from the flavonoid biosynthetic pathway was determined. Some genes were expressed in all grapes, even where little or no anthocyanins accumulated, but expression of the gene encoding a UDP glucose-flavonoid 3-o-glucosyl transferase (UFGT) was only detected in coloured grapes that synthesised anthocyanins. Southern and northern analysis of the white grapes indicated that the UFGT gene was present but was not expressed. Thus the lack of anthocyanins in white-skinned varieties or sports correlates with a lack of expression of the UFGT gene, although the expression of some other flavonoid pathway genes was also decreased.     

Preventing protein haze in bottled white wine

Slow denaturation of wine proteins is thought to lead to protein aggregation, flocculation into a hazy suspension and formation of precipitates. The majority of wine proteins responsible for haze are grape‐derived, have low isoelectric points and molecular weight. They are grape pathogenesis‐related (PR) proteins that are expressed throughout the ripening period post véraison, and are highly resistant to low pH and enzymatic or non‐enzymatic proteolysis. Protein levels in un‐fined white wine differ by variety and range up to 300 mg/L. Infection with some common grapevine pathogens or skin contact, such as occurs during transport of mechanically harvested fruit, results in enhanced concentrations of some PR proteins in juice and wine. Oenological control of protein instability is achieved through adsorption of wine proteins onto bentonite. The adsorption of proteins onto bentonite occurs within several minutes, suggesting that a continuous contacting process could be developed. The addition of proteolytic enzyme during short term heat exposure, to induce PR protein denaturation, showed promise as an alternative to bentonite fining. The addition of haze‐protective factors, yeast mannoproteins, to wines results in decreased particle size of haze, probably by competition with wine proteins for other non‐proteinaceous wine components required for the formation of large insoluble aggregations of protein. Other wine components likely to influence haze formation are ethanol concentration, pH, metal ions and phenolic compounds.     

果实粒径对‘美乐’和‘蛇龙珠’葡萄果实品质的影响

果实粒径普遍被认为是影响果实品质的一项重要指标。本实验以宁夏玉泉营地区的‘美乐’和‘蛇龙珠’葡萄为实验材料,将‘美乐’果粒分为大于14 mm（大果粒）、12～14 mm（中等果粒）、小于12 mm（小果粒）3 个粒径等级;将‘蛇龙珠’果粒分为大于15 mm（大果粒）、14～15 mm（中等果粒）、小于14 mm（小果粒）3 个粒径等级,连续两年测定不同粒径葡萄的可溶性固形物质量分数、可滴定酸质量浓度、花色苷单体含量以及单体酚含量。结果表明：连续两年两个葡萄品种均表现为中等果粒所占比例较高;2014年‘美乐’和‘蛇龙珠’葡萄果实的可溶性固形物质量分数随粒径的增大而降低,而2015年均表现为中等果粒较高;连续两年葡萄的种/果质量比和单果粒种子数均随粒径的减小而降低;2014、2015年酚类物质含量在‘美乐’中表现为小果粒和中等果粒较高,‘蛇龙珠’则为大果粒和中等果粒较高;‘美乐’中等果粒葡萄的花色苷单体总量最高,‘蛇龙珠’果实的花色苷单体含量受年份影响较大;单体酚总量以及黄酮醇类物质总量在‘美乐’葡萄中表现为在中等果粒中较高,‘蛇龙珠’葡萄则表现为在大果粒中较高。结论：中等果粒的‘美乐’葡萄和大果粒的‘蛇龙珠’葡萄酚类物质含量较高。     

Effect of postharvest dehydration on the composition of pinot noir grapes (Vitis vinifera L.) and wine

This study was conducted in order to improve our understanding of how phenolics and aroma compounds change in wine grapes during postharvest dehydration. Pinot noir grapes grown in the Willamette Valley of Oregon were harvested at 22.0 and 24.0 °Brix. Grapes harvested at 22.0 °Brix were divided into three equal lots with one lot immediately used for wine production, and the remaining two lots placed inside an air tunnel with an air speed of 1.0–1.8 m s⁻¹, 38% relative humidity and a temperature of 22 °C. The soluble solids content and weight loss were measured daily and wines were made from grapes when they reached 24.8 and 26.7 °Brix. The soluble solids of grapes increased about 1 °Brix per day; therefore, on the third and fourth day the berries reached the desired concentration; weight loss was 14 and 16%, respectively. Results from berry phenolic analysis indicated that per berry anthocyanin amount remained unchanged during dehydration. The composition of proanthocyanidins isolated from berries changed during dehydration. Volatile compounds in wines made from dehydrated grapes contained more terpenes and norisoprenoids (β-ionone, β-damascenone) when compared to wine made from the original fruit. Wines made from increasingly dehydrated grapes tended to resemble the composition and flavour profile of wines made from grapes left on the vine (i.e. with extended ripening). The results of this study suggest that postharvest flavour changes consistent with changes during fruit ripening can occur in grapes when harvested early and allowed to dehydrate under controlled conditions prior to fermentation.     

Deciphering the ability of different grapevine genotypes to accumulate sugar in berries

Background and Aims: To analyse the genetic determinants of berry sugar content in grapevine varieties, a method that combined measurements of total soluble solids (TSS) from berries sampled at a fixed stage after veraison with data on the yield and the leaf area was tested. Methods and Results: Over three seasons, differences in TSS at harvest for Riesling and Gewurztraminer grapes were explained by differences in the veraison dates and in the fruit‐to‐leaf ratios. TSS, yield and leaf area were also evaluated for 120 genotypes, which were progeny from a cross between Riesling and Gewurztraminer. Thermal timescales (degree‐days) proved relevant for describing sugar accumulation in the parent varieties, and when berries were sampled at a fixed heat sum after veraison in the progeny, the genotypic variability of sugar content was considerably reduced compared with the measurements on the same date at the end of the season. A negative relationship between the fruit‐to‐leaf ratio and the sugar content was also detected in the progeny. Conclusions: The evolution of TSS during berry ripening can be described using thermal timescales. Additionally, information on the yield and the leaf area needs to be integrated to analyse the behaviour of genotypes. Significance of the Study: A method to characterize the genotypic effect on fruit sugar accumulation after eliminating the contribution of veraison dates and crop load was proposed.     

冰酒：酒中贵妇

冰酒的生产 冰酒属于甜酒类。能否酿甜酒取决于酿酒的葡萄汁的含糖量。为什么用冰冻的葡萄能酿出甜酒呢？从传统冰酒的酿制工艺上讲．完全成熟并且晚收的葡萄,经历了风吹霜打会明显脱水．其糖分会提高．     

Shiraz berry size in relation to seed number and implications for juice and wine composition

This study was conducted over three seasons on irrigated Shiraz grapevines growing in a warm climate. We addressed the question of whether differences in berry size (within a population of berries from minimally pruned, own‐rooted or Ramsey‐grafted vines), would lead to differences in juice composition, wine composition or wine sensory score. Predictably, berry mass was found to increase with seed number, but berries in the smallest mass categories (0.3–0.7 g) still had similar juice soluble solids and pH; and similar concentrations of K+, tartaric acid and malic acid, compared with larger berries (1.4–2.0 g). Only for the very smallest mass category (0.3–0.55 g) was there any indication of better colour density (both for own‐rooted and Ramsey‐grafted vines) or higher anthocyanin concentration (for own‐rooted vines) compared with larger berries (1.4–2.0 g). Concentrations of tartaric acid and K+ in berry skins were highest in the smallest berry mass categories (0.3–0.7 g) and decreased with increasing berry mass (up to 1.4–2.0 g). A strong correlation (R²= 0.85) between skin tartaric acid and K+ concentrations was observed across that range. Small‐scale wine lots based on small berries (0.8–0.9 g) versus large berries (1.2–1.3 g) showed no differences in measures such as soluble solids, total acids or pH of juice; nor any differences in pH, total acids, K+, tartrate, malate, spectral characteristics or sensory score of corresponding wines. Moreover, small berries had a similar skin to fruit ratio, and a similar juice yield, compared to large berries. However, when measured post‐fermentation, the ratio of seed weight to skin weight was higher for small berries. The mass range of berries used here for small‐scale winemaking (i.e. from 0.8–0.9 g up to 1.2–1.3 g), covered the range of Shiraz berry mass typically found in irrigated vineyards (from 0.8 to 1.5 g), and thus confirms the relevance of present outcomes to practical winemaking. Finally, our data for variation in juice and wine composition as a function of berry size, showed consistent trends for all seasons, and thus implies that reported instances of improved wine quality from small berries (often associated with certain pruning treatments or deficit irrigation strategies), are more likely due to treatment effects that lead to small fruit, rather than to intrinsic developmental differences between large and small berries.     

Chemical and sensory analysis of verjuice: an acidic food ingredient obtained from unripe grape berries

Verjuice is the unfermented juice obtained from unripe grape berries, typically thinned fruit that is normally discarded. Despite a long history of use as a food ingredient, verjuice does not have a recognized standard of identity nor is made by standardized methods. To assess the potential for production in the Veneto region of Italy, verjuice produced from six different winegrape varieties harvested at three different dates from bunch closure through early veraison, and stabilized using either sulphite or sorbate, was subjected to compositional and sensory analyses. pH was found to range from 2.6 to 2.9 while soluble solids (°Brix) ranged from 3.8 to 9.9. Acidity (g/L) ranged from 17.4 to 40.5 while color (A₄₂₀) varied from 0.04 to 0.50. With respect to sensory character, harvest date had no influence on aroma, but affected taste, whereas the type of preservative used had no effect on taste, but did affect aroma.Industrial relevanceUnripe grape juice can be used as a food ingredient to provide acidity and flavor and may be suitable as an alternative to vinegar in salad dressings and other applications where the sensory character of acetic acid is unacceptable. Because it can be produced from thinned grapes, a currently unused by-product of winegrape growing, it represents a product of great interest to grape growers and to the food industry.     

Effect of UV–Vis Irradiation on Enzymatic Activities and Physicochemical Properties of Four Grape Musts from Different Varieties

The influence of ultraviolet–visible irradiation on some quality attributes (pH, soluble solids content, color parameters, absorption spectrum, vitamin C, total acidity, total phenolics, formol index, and total and reducing sugars) and polyphenol oxidase, peroxidase, and pectinmethylesterase activities of fresh grape juices was investigated. Grape juice was made from two varieties of white grapes (Victoria and Dauphine) and two varieties of pink grapes (Emperor and Red Globe). Each juice was irradiated for 140 min with a high-pressure mercury lamp of 400 W that emits in a range between 250 and 740 nm. Polyphenol oxidase was not completely inactivated during irradiation, reducing only 80% of its initial activity in juices from white grapes and only 50% in those from pink grapes. On the contrary, peroxidase was completely inactivated. A slight or nonexistent variation was observed in most of the measured physicochemical parameters, showing high stability during irradiation. Only vitamin C and color had a significant variation, with an average decrease of 30% for vitamin C in all varieties and a more important variation of color parameters in the pink varieties than in the white ones.     

不同品种荔枝果实加工特性比较研究

以25 个荔枝品种的果实为试材,利用常规的加工特性分析方法,进行果实的组成、理化指标、可溶性蛋白、总酚和总抗氧化能力的分析。结果表明：荔枝品种间果实出汁率、可溶性固形物含量、可食率、总酸、糖酸比差异较大,惠东红岩出汁率最高(70.76%),甜岩最低(32.77%),水晶球可溶性固形物最高(19.57%),香荔最低(12.00%)。荔枝品种的多酚氧化酶、过氧化物酶的活性和色泽稳定性差异较大。初步评价,惠东红岩、糯米糍、园枝、黑叶、中山状元红和白糖罂是适宜于果汁和果酒加工的优良品种。荔枝的可溶性蛋白、总酚和总抗氧化能力差异也较大,分别在0.03～1.26mg/L、11.75～487.35mg/L 和1.90～30.06mmol/L 之间。     

Rootstock effects on salt tolerance of irrigated field-grown grapevines (Vitis vinifera L. cv. Sultana). 3. Fresh fruit composition and dried grape quality

Field‐grown vines of cv. Sultana on either their own roots or grafted to a range of rootstocks, were drip‐irrigated at one of three salinity levels (0.40, 1.75 and 3.50 dS/m) over a five year period. Rootstocks were Ramsey, 1103 Paulsen, J17‐69 and 4 hybrids (designated R1, R2, R3 and R4) derived from parentage involving Vitis champini, V. berlandieri and V. vinifera. Grape juice total soluble solids, titratable acidity and pH were measured at harvest, while colour of dried fruit was measured before and after processing and again after six months storage. Damage index (an indicator of skin damage) was measured post‐processing; sugar crystal formation in dried grapes and dried grape compaction were measured post‐storage. There was a strong salinity x rootstock interaction for grape juice soluble solids concentration, soluble solids yield (the product of soluble solids concentration and fruit yield) and pH, but not for titratable acidity when analysed on the basis of 5 year means. Small increases (< 5%) in juice soluble solids concentration were recorded at medium salinity (1.75 dS/m) for the low vigour genotypes, Sultana on own‐roots and on J17‐69 rootstock, based on the 5 year means and Fisher's protected (interaction) LSDs. Moderate increases (< 10%) also occurred in years of low crop load e.g. 1993 at high salinity for the high vigour rootstock R2 and in 1995 at medium salinity for Sultana on own roots and at high salinity for Sultana on R1 rootstock. By contrast, decreases in soluble solids concentration occurred with increasing salinity for the high vigour rootstocks (Ramsey, 1103 Paulsen and R2) in years of high crop load e.g. 1992. Small (< 2%) increases in grape juice pH were recorded at high salinity for Sultana on R3 rootstock and moderate increases (< 7%) in grape juice titratable acidity were recorded at high salinity for Sultana on own roots and Sultana on J17‐69, R1, R2 and R4 rootstocks. Dried grapes from all treatments achieved a light amber colour (quality grade termed 5 crown light) and were generally of high quality. Sultanas from own‐rooted grapevines were redder (higher ‘a‐value’) than sultanas from 1103 Paulsen and Ramsey when assessed as unprocessed fruit, after processing (both years) and after 6 weeks storage. While soluble solids yields per vine were 23–31% lower at high salinity for Sultana on own roots and on R1, R3 and R4 rootstocks, they were unaffected by high salinity for Ramsey, 1103 Paulsen and R2 rootstocks. Moreover, soluble solids yields for Sultana on Ramsey, 1103 Paulsen and R2 rootstocks were 1.4 to 2.5‐fold higher than for Sultana on the other rootstocks at high salinity. This study has shown that over a 5 year period rootstocks such as Ramsey, 1103 Paulsen and R2 grafted with Sultana were tolerant of salinity, producing dried grapes of generally high quality.     

库尔勒香梨及其芽变和杂交品种（系）果实品质评价因子的选择

采用主成分分析法和聚类分析法对库尔勒香梨及其芽变和杂交的13 个品种（系）果实的主要品质性状 （单果质量、果肉硬度、果形指数、心果比、可溶性固形物含量、可溶性糖含量、可滴定酸含量、石细胞含量、 VC含量、糖酸比、汁液含量）进行了分析,以简化库尔勒香梨及其芽变和杂交品种（系）果实品质的评价指 标。结果表明：不同品种（系）的果实品质存在明显差异,果实石细胞含量和单果质量的变异系数较大,果实汁 液含量变异系数较小,部分品质性状之间存在简单的相关性;主成分分析提取出5 个主成分,累计方差贡献率为 88.964 5%,可以在一定程度上概括这些性状的总体信息量;依据不同品种（系）的主成分得分,筛选出的5 个代 表性的品种（系）分别为84-1-1、84-1-15、新梨9号、新梨8号、84-4-72。经聚类分析,可将库尔勒香梨及其芽变和 杂交品种（系）果实品质评价指标简化为单果质量、果形指数、石细胞含量、可溶性固形物含量和汁液含量5 个主 要指标。综合运用主成分分析和聚类分析方法,可以简化库尔勒香梨及其芽变和杂交品种（系）果实品质的评价指 标,有助于库尔勒香梨优良果实性状品种的评价与筛选。     

The effect of juice clarification, static or rotary fermentation and fining on ochratoxin A in wine

Semillon and Shiraz grapes containing ochratoxin A (OA) were produced by inoculation of bunches on the vine with Aspergillus carbonarius . Small scale vinification of these grapes was performed and the OA content at various stages was analysed. Semillon must was treated with pectolytic enzymes and the juice after pressing was fined with bentonite. Neither pectolytic enzymes nor bentonite influenced the OA content of the clarified juice. Shiraz must was vinified by either static or rotary fermentation. No differences in the OA content of wine after pressing were noted. OA was concentrated in juice lees and gross lees. However, additional juice or wine recovered from lees after centrifugation did not display increased OA contamination compared to racked juice or wine. Addition of bentonite at 2.5 g/L to a Semillon wine containing 56 mg grape-derived protein/L and ca. 8 μg OA/kg resulted in a 67% reduction in OA concentration. Potassium caseinate showed some effect, whereas gelatin, isinglass and PVPP did not significantly diminish OA in white wine compared to wine settled without fining agents. Addition of yeast hulls at 5.0 g/L to a Shiraz wine containing ca. 5 μg OA/kg yielded a 43% reduction. Gelatin was also slightly effective. Storage of wine for 10–14 months resulted in a decrease in OA concentration of 22% and 29% for white and red wines, respectively.     

Effect of freezing grape berries and heating must samples on extraction of components and composition parameters of red wine grape varieties

Juices from grape samples subjected to two storage methods (fresh and frozen) and two post-homogenisation treatments (21^oC and 71^oC) were examined for extraction of grape berry components and compared to a microvinified wine made from the same lot of fresh grapes. Cabernet Franc ( Vitis vinifera ) and Cynthiana ( Vitis aestivalis ) grapes were evaluated in 2003. Cabernet Franc, Cabernet Sauvignon ( Vitis vinifera ), Chambourcin (interspecific hybrid) and Cynthiana grapes were evaluated in 2004. Fresh grapes from each variety were sampled, analysed and prepared for microvinification. Frozen grapes of all varieties were thawed and analysed at the same time. For all varieties in both years, heating the must of fresh or frozen grapes increased the titratable acidity (11–58%), tartaric acid levels (12–110%), potassium content (15–62%), darkness (31–97%), red colour (54–1517%) and total red pigment values (36–1171%) of juice as compared to the juice from unheated must. For all varieties in 2004, heating the must from fresh or frozen grapes increased total phenolics (43–619%) of juice as compared to the juice from unheated must. Compared to fresh grape processing, freezing the grapes and then processing at 21^oC or 71^oC had varying results (increases and decreases) regarding the extraction of components in all varieties and both years but usually provided juice with composition most similar to that of the red wine produced by microvinification. Although the degree of extraction of individual components in the juice is influenced by selection of grape storage and must processing procedures, consistency of handling and procedure provided consistent results with low variability.