Instrumental Texture Analysis Parameters as Winegrapes Varietal Markers and Ripeness Predictors

The texture parameters of three red grape varieties (Mencía, Brancellao, and Merenzao) cultivated in Galician vineyards (North-West Spain) were determined. Different ripening stages (A: 176 ± 8 g/l reducing sugars; B: 193 ± 8 g/l reducing sugars; C: 210 ± 8 g/l reducing sugars; D: 227 ± 8 g/l reducing sugars) were also considered. Principal component analysis was performed for a better understanding of the differences found among grapes according to variety and ripening stage based on the skin and berry texture parameters. The parameters differentiating varieties were the skin break force and energy measured on the lateral side, whereas ripening stages can be classified on the basis of berry cohesiveness. The hardest berry skin was associated with the Merenzao variety with skin break force values comprised between 0.752–0.811 N and skin break energy between 0.715–0.790 mJ for A and B ripening stages, respectively. Instead, Brancellao variety presented the softest skin with skin break force values ranging from 0.521 to 0.562 N and skin break energy from 0.407 to 0.475 mJ for A and B ripening stages, respectively. Ripeness grade increased with the berry cohesiveness for all the varieties studied.     

Influence of skin hardness on dehydration kinetics of wine grapes

BACKGROUND: Knowledge of the influence of initial mechanical properties on the evolution of the weight loss of berries through the drying process is scarce. Therefore, the main purpose of this work was to investigate the effect of skin hardness at two different physiological stages of off‐vine drying kinetics of grapes. Skin hardness was evaluated as the berry skin‐break force parameter, measured by the texture analysis test. RESULTS: The decrease of berry weight as a function of the drying time was linear, indicating that the drying rates were constant within each cultivar studied (Moscato bianco and Erbaluce), and for each ripening stage and berry skin hardness. The drying rates decreased as berry skin hardness increased for the ripest grapes in the cultivars studied. CONCLUSION: The study allowed the assessment of the correlation between the skin hardness of fresh berries and the weight loss determined for different drying days. Copyright © 2010 Society of Chemical Industry     

Possible use of texture characteristics of winegrapes as markers for zoning and their relationship with anthocyanin extractability index

Ribeira Sacra Denomination of Origin is a steep slope viticulture area located in Galicia (northwest of Spain), and it is divided into five different subzones. Taking into account that grape composition depends not only on the grape cultivar used but also on the environmental factors and cultural practices, texture analysis has been proposed to assess the grape mechanical properties of those subzones. With the aid of principal component analysis, berry skin break energy measured on bottom side and berry cohesiveness have been suggested as the best mechanical properties for the subzones differentiation. Moreover, significant correlations among mechanical parameters and anthocyanin extractability index were found. A regression hyperplane allowed estimating anthocyanin extractability from berry skin thickness and Young′s modulus measured on the lateral side of grapes. The speed of mechanical analysis facilitates the planning and management of pressing and maceration processes as a consequence of the drastic reduction in sample treatment time.     

Physico‐mechanical evaluation of the aptitude of berries of red wine grape varieties to resist the compression in carbonic maceration vinification

By texture analysis tests, the ability of berries to resist rupture under compression load during intracellular fermentation was studied for twenty‐three red wine grape varieties. The softest berries were associated with Ancellotta (1.72 N), Dolcetto (1.79 N), Gamay (2.26 N) and Schiava gentile (2.29 N) cultivars. The hardest berries corresponded to Franconia and Bonarda cultivars (4.02–4.03 N). High resistance to splitting was also detected for Grenache, Raboso, Marzemino, Negramaro, Montepulciano and Croatina cultivars (3.50–3.95 N). The differentiating power of the mechanical variables of the whole berry and skin was assessed by univariate and multivariate analysis. Relationships among the instrumental berry hardness and other physical and mechanical properties were also investigated. The results obtained suggest that the manufacture of carbonic macerated wines should be planned considering the berry hardness, and it represents a new variable that should be considered in selecting the most appropriate wine grape variety to elaborate these wines.     

Modifications of mechanical characteristics and phenolic composition in berry skins and seeds of Mondeuse winegrapes throughout the on‐vine drying process

BACKGROUND: Among several common drying systems used in the enological sector the dry‐on‐vine (DOV) method assumes particular importance because famous wines such as Sauternes, Tokay and Ice Wines are produced by grapes dried using this system. Knowledge about trends in mechanical properties and phenolic composition during on‐vine grape drying is scarce. The objective of this current study is therefore to increase the knowledge on these aspects. RESULTS: Berry skin break energy (+0.10 N) and berry skin thickness (+69 µm) values increase during grape dehydration, while the peduncle detach force decreases (?0.86 N). Large reductions in the anthocyanin content have also been observed (?40%), but their profile does not show significant changes. Seed hardness (?7.10 N, ?1.40 mJ) decreases during the withering, and higher seed springiness has been observed. Seed proanthocyanidins (+2050 mg kg berry^?1) and flavanols vanillin assay (+670 mg kg berry^?1) increase progressively throughout the withering. In contrast, a distinct lowering of these substances in the skins was noted. CONCLUSION: Many modifications in the chemical–physical characteristics of berries of Mondeuse winegrapes throughout the DOV process were found. The mechanical characteristics of grapes, in particular the peduncle detachment force, are important parameters in assessing their suitability for the drying‐on‐plant process. Copyright © 2009 Society of Chemical Industry     

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.     

Cytoprotective effect of fruit extracts associated with antioxidant activity against ultraviolet rays

Antioxidant activity in the extracts of Redfield apple flesh, Pione grape berry skin, and Ishiji satsuma mandarin skin was evaluated by a superoxide dismutase (SOD) assay and hemolysis of red blood cell assay. Although SOD activity was higher in both the Redfield apple flesh and Pione grape berry skin, hemolysis of the red blood cells was delayed most in the Redfield apple flesh, followed by the Pione grape berry skin and Ishiji satsuma mandarin skin. The protective effects of extracts from these fruits against ultraviolet rays were also examined using human skin dermal fibroblasts. The Redfield flesh extract increased the percentage of cell viability against ultraviolet rays compared to the untreated control. The participation of polyphenolics in Redfield apples is discussed.     

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.     

Varietal Comparison of The Chemical,Physical, and Mechanical Properties of Five Colored Table Grapes

The visual attributes of table grapes, their chemical constituents, and mechanical properties are involved in consumer acceptability because they are correlated to sensory perception. Usually, instrumental measurements are preferred to the sensory evaluations because they reduce variations in subjective judgments and can be carried out more easily. In this work, chemical-physical attributes and texture properties of five black table grapes (Alphonse Lavallée, Black magic, Cardinal, Perlon, Regina nera) were studied in order to identify significant varietal differences. Spectrophotometric and HPLC methods and texture analysis test were used to evaluate color index, sugars and acid composition, phenolic characteristics, and mechanical properties of the skin and the pulp of berries. Many differences were found among varieties in technological maturity indexes, hydroxycinnamic acid, anthocyanin content and profile, and relative CIE L*, a*, b* parameters, but the more relevant differences were found in mechanical properties. Principal component analysis showed that the texture profile analysis parameters (hardness, cohesiveness, gumminess, and resilience) and berry skin characteristics (break skin energy, skin modulus of elasticy) were the best indices able to fulfill the aim of this work. Almost all of the parameters showed differences among cultivars, confirming their importance in the characterization of the variety as well as in the assessment of potential consumer acceptability. In particular, the cultivars demonstrated different reactions to the compression test; thus, the texture analysis parameters can be appropriate to explain varietal differences and to allow their differentiation.     

Impacts of crop level,soil and irrigation management in grape berries of cv ‘Trincadeira’ (Vitis vinifera L.)

Berry size and crop yield are widely recognized as important factors that contribute to wine quality. The final berry size indirectly affects the phenolic concentration of the wine due to skin surface-to-berry volume ratio. The effects of different irrigation levels, soil management and plant crop level on growth of ‘Trincadeira’ berries were studied. In order to test the influence of different irrigation levels (rainfed, pre-veraison and post-veraison), different soil management (tillage and natural cover crops) and different plant crop levels (8 and 16 clusters per vine), leaf water potential, skin anthocyanin, polyphenols, berry skin and seed fresh weight were measured in fruits. The segregation of berries into three different berry classes: small, medium and large, allowed to identify different levels of contribution of soil management and irrigation level into berry, skin and seeds ratios. As expected, higher water availability due to irrigation and soil tillage management during berry development induced an increase in berry flesh weight and this was more evident in larger berries; however, berry skin and seed fresh weight remained unchanged. Also, anthocyanins did not show significant differences.     

CIELAB coordinates in response to berry skin anthocyanins and their composition in Vitis

Abstract: Berry skin color OIV index, anthocyanin composition, and content of 78 grape cultivars were surveyed using a CIELAB system and high‐performance liquid chromatography (HPLC)‐mass spectrometry (MS) coupled with photodiode array detection. There were high correlations between L*, b*, and color, while a* was not a representative parameter. L* and b* values declined as berry skin color OIV became darker, and a* increased as berry skin color OIV became darker in pink and red grape cultivars only. The composition and content of anthocyanins varied widely among the cultivars. Total anthocyanins and types of anthocyanins were significantly correlated with color OIV parameters. Through multiple linear regression analysis, cyanidin derivatives had a positive effect on values of L* and b*. Delphinidin derivatives had positive effects on the value of a*. The CIELAB system gave good results for differentiation of grape berry skin color OIV.     

葡萄果实花色苷合成调控研究进展

果皮颜色是葡萄果实重要的商品品质之一,也是决定葡萄酒质量的关键因素,尤其是红葡萄酒。因此,果皮颜色一直是葡萄品种选育的重要目标性状。葡萄果皮颜色主要取决于花色苷的组成与含量,花色苷积累与尿苷二磷酸葡萄糖-类黄酮葡萄糖基转移酶（UDP-glucose 3-O-flavonoid glucosyltransferase,UFGT）基因表达呈显著正相关,而基因表达主要受MYB（v-myb avian myeloblastosis viral oncogene homolog）转录因子的调节。本文从MYB转录因子调节花色苷合成的分子机理及研究现状进行评述,并对该领域研究发展方向做简要分析。     

Effects of pre-bloom leaf removal on growth of berry tissues and must composition in two red Vitis vinifera L. cultivars

Background and Aims:  Little work has been conducted on the effects that summer pruning operations have on the relative growth of grapevine berry parts. Our paper studies whether pre-bloom leaf removal is able to modify the proportions of seed, skin and flesh in ripe grapevines berries and the related effects on must composition.
Methods and Results:  Pre-bloom defoliation (D) of the first six basal leaves on main shoots was applied to the field-grown cvs Barbera and Lambrusco salamino ( Vitis vinifera L.) in Italy's Po Valley and compared with non-defoliated controls. D showed reduced fruitset, hence yield per shoot, and concurrently improved must soluble solids and total anthocyanins in both cultivars as a likely result of increased leaf-to-fruit ratio (+3.4 cm²/g and +5.2 cm²/g for Barbera and Lambrusco, respectively) and improved relative skin mass (from 6.0 to 9.0% in Barbera and from 8.1 to 10.4% in Lambrusco). In both cultivars, skin and seed mass were highly correlated with total berry mass and changes in relative skin mass were generally not related to berry size.
Conclusions:  These results indicate that berry size per se is not the primary factor in determining final grape composition, which instead seems to depend upon factors differentially affecting the growth of the various berry components.
Significance of the Study:  Pre-bloom D induced a consistent, site and cultivar-independent increase in relative skin mass suggesting this effect being strongly physiologically regulated.     

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.     

Influence of extraction methodology on grape composition values

This work demonstrated similarities and differences in quantifying many grape quality components (>45 compounds) that were extracted from berries by three distinct preparations, before being analysed by eight spectrophotometric and HPLC methods. All sample extraction methods were appropriate for qualitative results only. Different extraction procedures showed altered component composition in ‘Pinot noir’ berries, possibly due to the localisation of the compounds of interest within the grape and how those compounds were extracted from the berry. Sample extraction is an often-overlooked part of berry evaluations, but this study illustrates that it should be carefully considered prior to berry component analysis for its influence upon measurements.     

A review of potassium nutrition in grapevines with special emphasis on berry accumulation

Potassium (K) is essential for vine growth and yield. Grape berries are a strong sink for K, particularly during ripening. Excess K levels in grape berries may have a negative impact on wine quality, mainly because it decreases free tartaric acid resulting in an increase in the pH of grape juice, must and wine. In Australia, high K status is common in most vineyards, which reflects the high K and high pH values of most Australian grape juice. This necessitates pH adjustment during the vinification process, and tartaric acid addition is a common practice in most Australian wineries. High K concentration may also lead to excessive loss of the additional tartaric acid by precipitation as potassium bitartrate and, as a consequence, pH adjustment becomes more difficult and expensive. Ensuring naturally low K levels in the berry will help reduce costs of input and waste management at the winery. Potential vineyard management options to manipulate berry K accumulation include selective use of rootstock/scion combination, canopy management and irrigation strategies. However, the impact of these practices on determining the optimum K concentration requires careful calibration of production parameters and the desirable grape juice and wine quality in relation to tissue K concentration. This paper reviews and discusses the possible functions of K in grape berries, translocation of K into the berry, and genetic and cultural factors that may affect the accumulation of K in the berry. This will help to identify the key research and management strategies needed for controlling K concentrations in grape berries.     

Effect of irrigation and variety on oxygen (δ18O) and carbon (δ13C) stable isotope composition of grapes cultivated in a warm climate

Background and Aims: δ¹³C values from Vitis vinifera leaves, whole grape, seed, pulp, skin and/or grape must sugars have been investigated as an integrated marker of vine water status or intrinsic water-use efficiency during berry growth and across region of origin, vintage and variety. The use of ¹⁸O/¹⁶O isotopic ratio as a marker of water addition, vintage and geographical origin has also been studied. This paper examines the effect of irrigation and grapevine variety on δ¹⁸O and δ¹³C of grape must from eight varieties, all cultivated in the same vineyard to reduce the effects from other variables. Methods and Results: Stable isotope compositions of grape must water and sugar were determined by isotope ratio mass spectrometry. The result of the study showed statistically significant effects of irrigation and vine variety on both δ¹⁸O and δ¹³C. The effect of vintage on δ¹⁸O was only significant for non-irrigated vines. Conclusion: This research highlights the effect of variety and irrigation on δ¹³C and δ¹⁸O of grape. Significance of the Study: This is the first report to demonstrate that the varietal effect on δ¹³C and δ¹⁸O of grape is not due only to differences in the vegetative cycle of each variety. It further suggests that water exhibits a lower isotopic discrimination in the indigenous Spanish varieties studied than in non-indigenous varieties.     

中国野生刺葡萄（Vitis davidii Foex）及其单品种葡萄酒中花旗松素含量分析

利用高效液相色谱-串联质谱联用技术对原产中国的野生刺葡萄果实的果皮、果肉、种子及单品种葡萄酒中的花旗松素含量（以鲜质量计算）进行测定与分析。结果表明：刺葡萄果实果皮中花旗松素含量最高,其含量在刺葡萄黑、白果实中分别为（2.44±0.18）、（2.03±0.14） mg/kg,在种子中分别为（1.66±0.13）、（1.38±0.12） mg/kg,果肉中含量最低,分别为（0.36±0.02）、（0.25±0.02） mg/kg。刺葡萄黑、白果实中各个部位花旗松素含量均无明显差异,但对照品种黑色果实果皮中的花旗松素含量显著高于白色果实,这说明花旗松素含量的高低与葡萄果皮颜色并无直接关系。在单品种酒中,白葡萄酒由于酿造工艺不同,果皮和种子中的花旗松素无法进入酒中,花旗松素含量仅为红葡萄酒的20%;葡萄酒中的花旗松素含量略低于果实是因为提取果实中花旗松素的溶剂是甲醇,而葡萄酒中只是水和乙醇的自然浸渍。     

Effects of ethephon, methanol, ethanol and girdling treatments on berry maturity and colour development in Cardinal table grapes

To hasten berry maturity and improve skin colour, the early-season table grape variety Cardinal was treated (post veraison) with a bunch + foliar spray using either 240 or 480 mg/L ethephon, as well as with 30% methanol, 30% ethanol (v/v); or by girdling. Treatment effects were evaluated in a randomised experimental design, with 10 replications of one plant per plot, down a single row. Ethephon at 480 mg/L applied twice, on July 2 when 5% of the berries showed colouring and on July 9 when 20% of the berries developed partial colour, increased total soluble solids, °Brix/titratable acidity and skin colour. Girdling, methanol and ethanol also increased total soluble solids and berry colouration and caused faster ripening. Ethephon at 480 mg/L was generally the most effective means of hastening ripening and improving colour.