Yeasts isolated from three varieties of grapes cultivated in different locations of the Dolenjska vine-growing region, Slovenia

The number and diversity of yeasts on grape berry surfaces are influenced by several factors, such as grape variety, degree of grape maturity at harvest, climatological conditions, geographic location, physical damage of grapes, the intensity of pest management etc. Cvicek is a typical Slovene wine, which has obtained a special protection under the Slovene Wine Law for its geographical origin. This blended red wine is produced from different grape varieties (Vitis vinifera L.), mostly from red grapes of Zametovka and Modra frankinja and from white grapes of Kraljevina. The aim of this study was to evaluate the impact of geographical locations in the Dolenjska vine-growing region and to obtain precise information about the influence of different grape varieties on the composition of yeast community on grape berries. The restriction fragment length polymorphism of PCR-amplified fragments from the rDNA gene cluster (PCR RFLP of rDNA) has been used for the differentiation of yeast species. The standard identification procedure has been performed on representative strains that shared identical RFLP profiles. The number of yeasts and yeast species isolated varied according to different grape varieties, Zametovka, Modra frankinja and Kraljevina (V. vinifera L.) and according to different sampling location. On the surface of grape berries 13 different yeast species have been identified. Saccharomyces cerevisiae has not been found.     

Isolation of epiphytic yeasts with potential for biocontrol of Aspergillus carbonarius and A. niger on grape

Antagonistic yeasts were isolated from the epiphytic flora associated with grape berries cv. Negroamaro and identified at species level using molecular methods. A total of 144 yeast isolates were tested in a preliminary screening on agar to select isolates showing a killer activity against Aspergillus carbonarius and A. niger, the main species responsible for the accumulation of ochratoxin A in grape. Twenty-eight yeast isolates were selected for their inhibitory effects on the above fungal species and assayed by an in vitro nutritional competition test for their antagonistic capacity towards three selected ochratoxigenic strains. Six yeast isolates belonging to five species, namely 2 isolates of Issatchenkia orientalis and one each of Metschnikowia pulcherrima, Kluyveromyces thermotolerans, Issatchenkia terricola and Candida incommunis, were finally selected and screened on wounded grape berries for their ability to inhibit infection by ochratoxigenic moulds. With the exception of the K. thermotolerans isolate, when inoculated at 10(9) CFU/wound, the other five challenger yeasts reduced the A. carbonarius and A. niger colonization on grape berry (P<0.05). In particular, the best antagonistic activity was shown by the two I. orientalis isolates. Results suggest that antagonist yeasts with the potential to control A. carbonarius and A. niger on grape can be found among the microflora associated with the berries.     

The microbial ecology of wine grape berries

Grapes have a complex microbial ecology including filamentous fungi, yeasts and bacteria with different physiological characteristics and effects upon wine production. Some species are only found in grapes, such as parasitic fungi and environmental bacteria, while others have the ability to survive and grow in wines, constituting the wine microbial consortium. This consortium covers yeast species, lactic acid bacteria and acetic acid bacteria. The proportion of these microorganisms depends on the grape ripening stage and on the availability of nutrients. Grape berries are susceptible to fungal parasites until véraison after which the microbiota of truly intact berries is similar to that of plant leaves, which is dominated by basidiomycetous yeasts (e.g. Cryptococcus spp., Rhodotorula spp. Sporobolomyces spp.) and the yeast-like fungus Aureobasidium pullulans. The cuticle of visually intact berries may bear microfissures and softens with ripening, increasing nutrient availability and explaining the possible dominance by the oxidative or weakly fermentative ascomycetous populations (e.g. Candida spp., Hanseniaspora spp., Metschnikowia spp., Pichia spp.) approaching harvest time. When grape skin is clearly damaged, the availability of high sugar concentrations on the berry surface favours the increase of ascomycetes with higher fermentative activity like Pichia spp. and Zygoascus hellenicus, including dangerous wine spoilage yeasts (e.g. Zygosaccharomyces spp., Torulaspora spp.), and of acetic acid bacteria (e.g. Gluconobacter spp., Acetobacter spp.). The sugar fermenting species Saccharomyces cerevisiae is rarely found on unblemished berries, being favoured by grape damage. Lactic acid bacteria are minor partners of grape microbiota and while being the typical agent of malolactic fermentation, Oenococcus oeni has been seldom isolated from grapes in the vineyard. Environmental ubiquitous bacteria of the genus Enterobacter spp., Enterococcus spp., Bacillus spp., Burkholderia spp., Serratia spp., Staphylococcus spp., among others, have been isolated from grapes but do not have the ability to grow in wines. Saprophytic moulds, like Botrytis cinerea, causing grey rot, or Aspergillus spp., possibly producing ochratoxin, are only active in the vineyard, although their metabolites may affect wine quality during grape processing.The impact of damaged grapes in yeast ecology has been underestimated mostly because of inaccurate grape sampling. Injured berries hidden in apparently sound bunches explain the recovery of a higher number of species when whole bunches are picked. Grape health status is the main factor affecting the microbial ecology of grapes, increasing both microbial numbers and species diversity. Therefore, the influence of abiotic (e.g. climate, rain, hail), biotic (e.g. insects, birds, phytopathogenic and saprophytic moulds) and viticultural (e.g. fungicides) factors is dependent on their primary damaging effect.     

赤霞珠葡萄生长发育过程中内源激素的变化及其与果实成熟的关系

为研究赤霞珠葡萄果实发育过程中不同组织(果皮、果肉和种子)内源激素的含量变化及其与果实成熟的关系,用高效液相色谱-质谱联用技术测定果实发育过程中果皮、果肉以及种子中脱落酸(abscisic acid,ABA)、生长素(indole acetic acid,IAA)、赤霉素(gibberellin A_3,GA_3)、茉莉酸(jasmonic acid,JA)和水杨酸(salicylic acid,SA)的含量。结果发现,在葡萄果实生长发育过程中,葡萄果皮和果皮中ABA含量呈双S型变化,花后20 d左右,ABA含量较高,随着果实膨大开始下降,随后开始上升,至转色中期达到最大值,随着果实的成熟缓慢下降;果皮、果肉和种子中GA_3含量均是从果实膨大期开始上升,膨大后期下降,随后在转色初期又开始上升,随后下降;JA含量的变化与GA_3类似;果皮和果肉中IAA含量首先略微下降,在果实快速生长期迅速上升,并达到峰值,随着果实进入转色期,含量逐渐下降并保持稳定,果实膨大期之前,种子中IAA含量较高,随着果实膨大降低,并维持在较低水平,SA含量的变化与IAA类似。结论:ABA、GA_3、JA含量与赤霞珠果实成熟有关,IAA、GA_3、SA、JA含量与赤霞珠果实生长有关。     

Berry nitrogen status altered by cover cropping: Effects on berry hormone dynamics,growth and amino acid composition of Pinot Noir

The influence of altered nitrogen (N) content, caused by cover crop, on Pinot Noir berry quality was studied. Treatments included two levels of cover cropping and clean-cultivation. Berry N-content was reduced by grass cover crop competition, with the highest reductions of N at the early stage of berry formation and at the commercial harvest stage. Growth regulators, trans-zeatin and indole-3-acetic acid, and berry growth were influenced by the changes in N-status at different stages of berry formation. The total amino acid content of berries at harvest decreased with cover cropping, while the proline to arginine ratio and assimilable amino acids content improved compared to the berries from clean-cultivated vines. Our data indicate that early stage berry development is influenced by N-status but finally it results in an improved amino acid composition for yeast fermentation in mature berries. At the same time, sugar and pigment contents were not negatively influenced by cover crop-induced changes in berry N-status.     

Mass-spectrometry evidence confirming the presence of pelargonidin-3-O-glucoside in the berry skins of Cabernet Sauvignon and Pinot Noir (Vitis vinifera L.)

Background and Aims: Anthocyanins are a group of important phenolic compounds which are responsible for the colour of red grape and wine. This study aimed to confirm the existence of pelargonidin-3-O-glucoside in Vitis vinifera grape berry skins. Methods and Results: The anthocyanin profiles in the berry skins of Cabernet Sauvignon and Pinot Noir were analysed by high performance liquid chromatography – electronic spray ionization – tandem mass spectrometry. Besides 17 anthocyanins that are commonly determined in the berries of these two varieties, pelargonidin-3-O-glucoside was also detected at trace levels. Conclusions: The mass-spectrometry evidence confirmed the existence of pelargonidin-3-O-glucoside in non-teinturier V. vinifera grapes. Significance of the Study: This finding will be beneficial for the further understanding of anthocyanin profile and its biosynthesis in grape berries.     

延迟采收对酿酒葡萄类黄酮物质的影响

以梅鹿辄和赤霞珠葡萄为实验材料,研究延迟采收对葡萄类黄酮物质的影响。结果表明：延迟采收后酿酒葡萄果粒质量和果粒纵径均降低,可溶性固形物的含量增加,可滴定酸含量降低。梅鹿辄果皮中共检测出19 种花色苷、6 种黄烷醇和15 种黄酮醇,延迟1 周后,黄烷醇和黄酮醇含量增加,相较于对照分别增加了69%和1.67%,延迟2～3 周后黄烷醇和黄酮醇含量降低;而延迟采收后,花色苷含量下降。赤霞珠果皮中共检测出15 种花色苷、4 种黄烷醇和15 种黄酮醇,花色苷、黄烷醇和黄酮醇的含量在延迟3 周后显著增加,相较于对照分别增加了22%、102%、80%。     

Influence of shriveling on berry composition and antioxidant activity of Cabernet Sauvignon grapes from Shanxi vineyards

BACKGROUND: Berry shrivel (BS), a berry development disorder, appears soon after veraison. It occurs worldwide and affects the quality of grape berries and wine. However, it had not been reported in China until recently. This study aimed to investigate the changes in berry composition and antioxidant activity of Cabernet Sauvignon grapes from Xiangning Valley, Shanxi Province, China, during BS. RESULTS: Shrinkage contributed to an increase in the concentration of basic grape ingredients such as sugar and acid. An appropriate degree of shrinkage was apparently helpful in improving the phenolic content and increasing the antioxidant activity, but the berries that continued to shrivel showed a low antioxidant activity. Further, the results indicated distinct differences between the berries harvested from the southern side of the canopy and those harvested from the northern side, presumably due to variations in sunlight exposure. CONCLUSION: Moderate BS was beneficial since it increased berry quality and antioxidant activity of Cabernet Sauvignon grapes from Shanxi vineyards. Copyright © 2011 Society of Chemical Industry     

The influence of seed weight on the development and growth of berries and live green ovaries in Vitis vinifera L. cvs. Pinot Noir and Cabernet Sauvignon

Background and Aims:  Variation in berry size is observed at harvest. Although the growth of seeded berries has been described, no such data are reported for seedless berries or live green ovaries that occur in wine cultivars. This study describes the growth of individual berries in relation to seed development.
Methods and Results:  Regular measurements of berry diameter described the growth of Pinot Noir and Cabernet Sauvignon. Seeded berries had typical double sigmoid growth curves, whereas seedless berries, which developed more slowly from midway through Phase I, continued to grow in Phase III if a seed trace was present. Berries without a seed trace did not enlarge after Phase II. Live green ovaries failed to grow after a small initial expansion post-cap fall.
Conclusion:  Seeded berries had double sigmoid growth as a result of cell division and expansion, whereas the growth of seedless berries and live green ovaries was the result of cell expansion alone. Seed development is necessary for cell division within the mesocarp.
Significance of the Study:  Seed development is essential for the full development of Pinot Noir and Cabernet Sauvignon berries. The data suggest that divergence of berry development from a characteristic growth curve may be linked to the extent of seed development.     

陕西合阳地区酿酒葡萄果实成熟特性研究

该实验研究了合阳地区5个红色和5个白色酿酒葡萄品种在成熟期的可溶性固形物、还原糖、总酸含量和成熟系数变化,分析了成熟葡萄浆果的物理品质、花色苷和单体酚的组成和含量。结果表明,转色期后12 d,各品种葡萄的成熟系数均＞20。成熟葡萄浆果还原糖含量为180～235 g/L,总酸含量＜6 g/L。综合来看,赤霞珠、品丽珠、黑比诺、马瑟兰、爱格丽、小芒森和贵人香适合在合阳地区种植。赤霞珠、品丽珠、黑比诺、马瑟兰和贵人香最适采收期在转色期后24 d左右,爱格丽和小芒森在转色期后44 d左右。马瑟兰的成熟浆果花色苷含量较高,达29.85 mg/g;赤霞珠、马瑟兰和爱格丽成熟浆果单体酚含量较高,分别为0.65 mg/g、0.43 mg/g和0.26 mg/g。研究结果将为陕西合阳地区酿酒葡萄种植与推广提供参考。     

Yeasts found in vineyards and wineries

Wine is a complex beverage, comprising thousands of metabolites that are produced through the action of a plethora of yeasts and bacteria during fermentation of grape must. These microbial communities originate in the vineyard and the winery and reflect the influence of several factors including grape variety, geographical location, climate, vineyard spraying, technological practices, processing stage and season (pre‐harvest, harvest, post‐harvest). Vineyard and winery microbial communities have the potential to participate during fermentation and influence wine flavour and aroma. Therefore, there is an enormous interest in isolating and characterising these communities, particularly non‐Saccharomyces yeast species to increase wine flavour diversity, while also exploting regional signature microbial populations to enhance regionality. In this review we describe the role and relevance of the main non‐Saccharomyces yeast species found in vineyards and wineries. This includes the latest reports covering the application of these species for winemaking; and the biotechnological characteristics and potential applications of non‐Saccharomyces species in other areas. In particular, we focus attention on the species for which molecular and genomic tools and resources are available for study. Copyright © 2016 John Wiley & Sons, Ltd.     

Ochratoxin A occurrence and formation in Portuguese wine grapes at various stages of maturation

A total of 93 Portuguese grape samples destined for wine production were examined for the presence of ochratoxin A (OTA) and the OTA producing fungi Aspergillus carbonarius and A. niger aggregate. Samples came from 11 vineyards from four winemaking regions in the North and South of the Portuguese mainland, during the harvest seasons of 2001, 2002 and 2003. Grapes were examined at 3 maturation stages, from setting to the harvesting period, to evaluate when contamination with OTA producing fungi and OTA synthesis occur. The detection of fungi in grape samples was made by plating methods with and without surface disinfection. OTA was formed by 14% of the 650 isolates tested. Most of the OTA producing strains (96%) were isolated at harvest time. At this stage, the percentage of grape samples with OTA producing strains detected without surface disinfection was 56%. With surface disinfection, A. carbonarius was isolated from 10% of the samples. OTA was detected in grapes at the 3 maturation stages. The average OTA concentrations in 60 samples at pea berry (28 samples), early veraison (22 samples) and ripe berry (20 samples) were 263, 149 and 35 ng/kg, respectively. Experiments with an A. carbonarius strain demonstrated that OTA production differs significantly with the composition of the berries at different maturation stages (P<0.001), with a mean value of OTA production at pea berry, early veraison and ripe berry of 3402, 1530 and 22 mug/kg, respectively. The production of OTA by A. carbonarius was correlated positively and negatively with the total acidity of grapes (r(s)=0.855, P<0.001) and reducing sugars content (r(s)=-0.835, P<0.001), respectively. Our data demonstrate that OTA synthesis in grapes occurs since early maturation stages.     

圆叶葡萄种子发育过程中多酚积累特性

以栽培于广西地区2 个圆叶葡萄品种‘Noble’和‘Carlos’为实验材料,以真葡萄品种‘赤霞珠’和‘雷司令’为对照,使用超高效液相色谱-串联三重四极杆飞行时间质谱,分析其种子发育过程中多酚组成和积累特性。结果表明：在4种葡萄发育过程的种子样品中共检测到106种多酚,包括48种鞣花酸及前体物、24种黄酮醇、20种羟基苯甲酸、9种黄烷-3-醇、3种芪类和2种羟基肉桂酸。鞣花酸及前体物（主要是前体物）和黄烷-3-醇（主要是没食子酰化体和单体）分别是圆叶葡萄和真葡萄种子中最主要的多酚类型,但其含量在不同年份和品种间具有较大差异。前体物含量在圆叶葡萄‘Noble’幼果期种子中较高,然后逐渐下降,完全转色后再次上升;‘Carlos’则在浆果转色前种子中含量较高,随后略有下降。黄烷-3-醇在真葡萄‘雷司令’种子中2013年随着浆果发育含量显著升高,转色时含量达到最高,随后有所下降,2014年不受发育期的影响;‘赤霞珠’则分别在2013年幼果期和2014年果实完熟时的种子中含量最高。     

Yeast interactions and wine flavour

Wine is the product of complex interactions between fungi, yeasts and bacteria that commence in the vineyard and continue throughout the fermentation process until packaging. Although grape cultivar and cultivation provide the foundations of wine flavour, microorganisms, especially yeasts, impact on the subtlety and individuality of the flavour response. Consequently, it is important to identify and understand the ecological interactions that occur between the different microbial groups, species and strains. These interactions encompass yeast-yeast, yeast-filamentous fungi and yeast-bacteria responses. The surface of healthy grapes has a predominance of Aureobasidium pullulans, Metschnikowia, Hanseniaspora (Kloeckera), Cryptococcus and Rhodotorula species depending on stage of maturity. This microflora moderates the growth of spoilage and mycotoxigenic fungi on grapes, the species and strains of yeasts that contribute to alcoholic fermentation, and the bacteria that contribute to malolactic fermentation. Damaged grapes have increased populations of lactic and acetic acid bacteria that impact on yeasts during alcoholic fermentation. Alcoholic fermentation is characterised by the successional growth of various yeast species and strains, where yeast-yeast interactions determine the ecology. Through yeast-bacterial interactions, this ecology can determine progression of the malolactic fermentation, and potential growth of spoilage bacteria in the final product. The mechanisms by which one species/strain impacts on another in grape-wine ecosystems include: production of lytic enzymes, ethanol, sulphur dioxide and killer toxin/bacteriocin like peptides; nutrient depletion including removal of oxygen, and production of carbon dioxide; and release of cell autolytic components. Cell-cell communication through quorum sensing molecules needs investigation.     

Characterization of the yeast ecosystem in grape must and wine using real-time PCR

The complex microbial ecosystem of grape must and wine harbours a wide diversity of yeast species. Specific oligonucleotide primers for real-time quantitative PCR(QPCR) were designed to analyse several important non-Saccharomyces yeasts (Issatchenkia orientalis, Metschnikowia pulcherrima, Torulaspora delbrueckii, Candida zemplinina and Hanseniaspora spp.) and Saccharomyces spp. in fresh wine must, during fermentation and in the finished wine. The specificity of all primer couples for their target yeast species were validated and the QPCR methods developed were compared with a classic approach of colony identification by RFLP-ITS-PCR on cultured samples. Once the methods had been developed and validated, they were used to study these non-Saccharomyces yeasts in wine samples and to monitor their dynamics throughout the fermentation process. This study confirms the usefulness and the relevance of QPCR for studying non-Saccharomyces yeasts in the complex yeast ecosystem of grape must and wine.     

橡木提取液对霞多丽和赤霞珠葡萄果实品质的影响

主要研究橡木提取液对葡萄果实品质的影响。以欧亚种（Vitis vinifera L.）酿酒葡萄品种赤霞珠和霞多 丽为实验材料,外源喷施橡木提取液后测定果实单宁、多酚、花色苷、单糖和有机酸单体含量及香气成分的质量 浓度。结果表明：橡木提取液对葡萄果实基本理化性质影响不显著,橡木提取液可提高霞多丽果实总酚和单宁含 量,其中体积分数25%美国橡木提取液处理组单宁含量比对照组（喷蒸馏水,下同）增加了33.2%;橡木提取液可 提高赤霞珠果实单宁和总花色苷含量,与对照组相比,体积分数25%美国橡木提取液处理后赤霞珠单宁含量增加 了40.7%,纯美国橡木提取液处理后花色苷含量增加了10.7%;纯橡木提取液可以提高霞多丽和赤霞珠果实果糖含 量;橡木提取液可以提高霞多丽和赤霞珠果实葡萄糖含量。橡木提取液对霞多丽和赤霞珠果实香气成分有很大影 响,都增加了果实香气成分的种类,尤其是酯类、醛类和醇类（如橡木内酯、四氢薰衣草醇）,同时可增加果实香 气质量浓度,如体积分数25%美国橡木提取液可使6-甲氧基丁子香酚的质量浓度增加近8 倍。外源喷施橡木提取液 可改善葡萄果实品质,结果可为葡萄产业废弃物开发利用提供理论依据。     

Effect of the cluster heterogeneity on mechanical properties,chromatic indices and chemical composition of Italia table grape berries (Vitis vinifera L.) sorted by flotation

The impact of cluster heterogeneity on mechanical properties, chromatic indices and chemical composition of Italia table grape berries sorted by flotation was evaluated in this study. The density sorting at commercial harvest permitted to get berries of different ripeness and relatively different quality attributes. Individually, some grape chromatic characteristics, physical characteristics (weight of the whole berry and berry skin), content and composition of reducing sugars, organic acids and phenolic compounds (flavanols of low molecular mass in berry skins) permitted to characterise and to differentiate berries belonging to different density classes. However, the tested mechanical properties were not related to the berry density. When the variables that significantly contributed to the berry differentiation were globally assessed, the chemical parameters related to sugars (142.3–164.4 g kg^?1), content of skin oligomeric flavanols [46.3–137 mg (+)‐catechin kg^?1], berry skin weight (379–607 mg), yellow/blue colour component (26.31–29.96) and chroma (26.40–30.06) were the more representative.     

Biochemical comparison of two grape varieties differing in juice acidity

The winegrape cv. Cabernet Sauvignon and the tablegrape cv. Gora Chirine (both Vitis vinifera L.) differ in the acidity of their berry juice. The changes in pH, titratable acidity and the concentration of compounds of the berry juice were measured from 20–30 d before veraison to harvest on plants cultivated in the glasshouse. The difference in acidity between the juice of the two varieties appeared before veraison. At harvest, the berry juice of Gora Chirine had a pH of 5.2 and titratable acidity (TA) of 32 meq/L while that of Cabernet Sauvignon had a pH of 3.2 and TA of 150 meq/L. To evaluate cellular compartmentation in the berry pericarp, vacuolar pH was measured on intact berries at two growth stages, using ¹³C nuclear magnetic resonance (NMR). Vacuolar pH did not differ significantly between the two cvs. The lower TA of Gora Chirine juice could be attributed to lower concentrations of all three major acids, malic, tartaric and citric, and to a higher concentration of potassium. At veraison, the malic acid concentration in the berry juice of Cabernet Sauvignon was about seven times higher than that of Gora Chirine. The accumulation of hexoses, especially glucose, occurred earlier during the berry growth cycle in Gora Chirine than in Cabernet Sauvignon. The osmotic potential of the Gora Chirine juice, before veraison, was lower than could have been expected because of low acidity. This was due to the compensatory effect of early accumulation of glucose. Amino acid concentration was significantly higher in Gora Chirine than in Cabernet Sauvignon, especially just before veraison. The role of organic acids in berry acidity and osmotic potential, and various metabolic processes that may lead to the difference in organic acid concentration, are discussed.     

中国野生葡萄果实基本品质、酚类物质含量及其抗氧化活性分析

中国野生葡萄资源丰富,但对其利用有限;为揭示不同种野生葡萄的品质差异及进一步利用奠定理论基础,本研究对中国野生葡萄的10个种(46个株系)和不同对照品种(4份材料)的基本品质、酚类物质含量及其抗氧化活性指标进行评价。结果表明:1)除刺葡萄外,中国野生葡萄的单果质量小于‘赤霞珠’;中国野生葡萄的皮果比高于‘赤霞珠’。2)中国野生葡萄和对照之间糖的组成相似,果糖与葡萄糖所占的比例没有差异,总糖含量显著低于‘赤霞珠’和‘户太8号’;除刺葡萄外,中国野生葡萄的总酸含量显著高于对照‘赤霞珠’和‘户太8号’,中国野生葡萄的酒石酸/苹果酸的比值低于‘赤霞珠’,说明中国野生葡萄属于高苹果酸型;河岸葡萄和圆叶葡萄的糖酸含量与中国野生葡萄的糖酸含量较接近;‘赤霞珠’和‘户太8号’属于高糖低酸型,中国野生葡萄属于低糖高酸型。3)中国野生葡萄的抗氧化活性和酚类物质的含量变异较大,大部分的野生葡萄与‘赤霞珠’的酚类物质含量和抗氧化活相近,但中国野生葡萄的花色苷含量高于对照的花色苷含量。综上所述,中国野生葡萄中的燕山葡萄、蘡薁葡萄和刺葡萄的品质较好,其与‘赤霞珠’和‘户太8号’的糖酸组分、酚类物质含量及抗氧化活性接近。     

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。