浸渍酶对蛇龙珠葡萄酒酿造过程中类黄酮化合物变化的影响

研究了浸渍酶Lallzyme Ex-V对蛇龙珠葡萄酒酿造过程中(从酒精发酵到橡木桶贮藏12个月)类黄酮动态变化的影响。结果显示,经浸渍酶处理加快了儿茶素、表儿茶素、杨梅素、山奈酚和槲皮素等5种类黄酮化合物在葡萄酒酒精发酵期间的浸提速度,但不影响杨梅素和槲皮素在后续酿造过程中的含量,杨梅素在葡萄酒酒精发酵结束后含量逐步下降,槲皮素在橡木桶陈酿期间含量逐渐增加;酶处理对儿茶素和表儿茶素的影响一直持续到苹-乳发酵的第2周,酶处理酒中儿茶素和表儿茶素的含量高于对照;浸渍酶对山奈酚含量的影响一直持续到橡木桶陈酿3个月,处理酒中的含量高于对照。     

利用AMDIS技术解析雷司令果实发育过呈中的降异戊二烯类香气物质

自动质谱图解卷积和鉴定系统(AMDIS)是美国标准化委员会推出的一款辅助气质数据定性分析的软件,利用该软件可有效的克服GC-MS定性分析中基质效应和共洗脱效应的干扰,增加解谱的准确性和可靠性.本研究将GC-MS检测技术和AMDIS辅助解谱相结合,从雷司令葡萄果实中鉴定出15种降异戊二烯类物质,他们多数以游离态形式存在,在果实发育早期或转色前期含量最高;此外还检测到4种结合态该类化合物.在成熟果实中,β-大马士酮和β -紫罗兰酮含量远高于其感觉阈值,呈现煤油味的TDN也略高于其阈值.该研究为AMDIS技术在果实香气成分分析中的推广应用提供了参考.     

藤稔葡萄不同节位芽的发育及结果能力分析

花芽分化是葡萄产量形成的生理基础。为了解葡萄不同节位芽发育的情况,本试验以6年生藤稔品种为试材,通过在枝条不同节位进行修剪并仅保留顶部2个芽的处理,研究了不同节位芽萌发新梢的开花及结果习性。结果表明,不同节位的修剪处理均不同程度地增加了结果枝的粗度和花序数,果穗和果实性状也有所提高。     

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.     

Effect of irrigation on changes in the anthocyanin composition of the skin of cv Tempranillo (Vitis vinifera L) grape berries during ripening

The impact of water availability on the yield and on the chemical composition in the skins of cv Tempranillo grapes at different phases of berry growth was studied over a 2 year period by determining changes in berry weight, °Brix, titratable acidity, pH and different phenolic compounds. The evolution of phenolic compounds during berry growth followed similar patterns to those reported by previous investigators. Over the 2 year study, concentrations of total phenols and total tannins in the skins were always higher for the non-irrigated than for the irrigated vines, though the differences were not significant on some sampling dates. Total anthocyanin concentrations in 1992 were significantly higher in the non-irrigated than in the irrigated grapes, except at véraison and harvest. In contrast, in 1993, concentrations were higher in the non-irrigated grapes on the first three sampling dates and in the irrigated grapes on the last three sampling dates, but with significant differences only on day 136 after budbreak. In the first year, anthocyanin concentrations for the non-irrigated grapes were higher than for the irrigated grapes, except at harvest, though the differences at harvest were not significant. However, in the second year, concentrations in the berries from the irrigated vines were significantly higher on most sampling dates. In both years, concentrations of the five anthocyanins at harvest were higher for the irrigated treatment, the treatment that produced higher berry weights and crop yields. © 2001 Society of Chemical Industry     

An assessment of rootstocks for Sunmuscat (Vitis vinifera L.): a new drying variety

Sunmuscat scions, either grafted onto one of seven rootstock, or as own-rooted vines, were grown under irrigation according to the practices of warm-climate viticulture in north-western Victoria. The trial was located within a commercial vineyard on a sandy loam soil, and represented a typical replant situation. Grapevine performance was assessed over five seasons, viz. 1999–2004 inclusive, in terms of yield per vine, berry weight, juice composition and vigour (based on trunk girth). The highest yielding rootstock over the trial period was 1103 Paulsen (28.9 kg /vine) followed by 140 Ruggeri and Ramsey (26.1 and 25.8 kg /vine respectively), S04 (22.5 kg /vine), Schwarzmann, 101-14 and Teleki 5A (19.9, 18.7 and 18.4 kg /vine respectively). Scions on their own roots returned lowest yield (15.5 kg /vine). Berry weights were largest for the three high yielding rootstocks (2.3 g) and smallest with own roots (2.0 g). Total soluble sugars in harvested fruit were largely unaffected by rootstock in most seasons, although taken over all seasons, fruit from scions grafted onto Ramsey rootstock had the lowest levels, while Teleki 5A had the highest levels (viz. 23.4^oBrix and 24.7^oBrix respectively). Comparative vigour for all seven graft combinations was inferred from trunk circumference. There was a 2-fold difference in rootstock girth below the graft union (viz. 265 mm for 1103 Paulsen, compared to 135 mm for S04), whereas differences in the scion girth above the graft union were minor (only 16%). Relative compatibility of scion and stock was inferred from 'girth ratio' of trunk circumference above compared with below the graft union. Girth ratio was highest for Sunmuscat scions grafted onto SO4 rootstock, and lowest for scions on 1103 Paulsen. Scion girth and vine yield were broadly correlated.     

Management practices for Sunmuscat (Vitis vinifera L.): a new drying variety

Sunmuscat grapevines, managed on one of three trellis × two row spacing configurations, and grown on either their own roots or grafted onto Ramsey rootstock, were assessed over nine seasons (1990–1998 inclusive). The three trellis systems comprised (1) a 0.3 m narrow T‐trellis (NT), (2) a 1.2 m wide T‐trellis (WT), both with a 3.3m row spacing and a height of 1.2 m, and (3) a high (1.8 m) hanging cane (HC) system based on bi‐lateral cordons with a 2.2 m row spacing. Vine spacing within rows was 2.4 m irrespective of row width. A trellis drying treatment was compared with hand harvest during 1991–1995. Over the nine seasons, individual WT vines sustained highest yields of fresh grapes (23.7 kg/vine.season) compared to either NT (20.9 kg/vine) or HC vines (20.8 kg/vine) respectively (P < 0.001). However, HC vines expressed a considerable production advantage on a per hectare basis, viz. 41.3 t/ha, due to closer row spacing. Corresponding vineyard productivity for NT and WT vines was 26.4 and 29.9 t/ha respectively. Both WT and HC vines showed significantly higher bunch and shoot numbers than the NT treatment (P < 0.05 and P < 0.001, respectively). Nevertheless, trellis treatment had no effect on fruitfulness, berry weight, bunch weight, total soluble solids or titratable acidity. Taken overall, vines grafted to Ramsey rootstock had higher mean yields than vines on their own roots (i.e. 23.6 and 20.1 kg /vine, respectively P < 0.001) due to more berries per bunch and larger berries, despite having significantly fewer shoots and bunches. There was no long term evidence for incompatibility of Sunmuscat grafted to Ramsey rootstock. Compared to hand harvest of fresh grapes, trellis drying had no effect on yield, shoot and bunch numbers. Development of significantly smaller berries with trellis drying was offset by higher levels of total soluble solids. Sunmuscat is clearly a highly productive variety and is suited to canopy management on tall, cordon‐based hanging cane systems which are also amenable to trellis drying.     

Susceptibility of 44 grapevine (Vitis vinifera L.) varieties to downy mildew in the field

Background and Aims: Downy mildew, which occurs worldwide, is one of the most destructive of all grapevine diseases. Several authors have examined the host–pathogen interaction in different Vitis species, crosses and hybrids, but only a few studies comparing this in true V. vinifera varieties have been undertaken. The aim of the present study was to examine the in‐field susceptibility to infection by Plasmopara viticola, the causal agent of downy mildew, of 44 grapevine varieties, all belonging to the collection of the Misión Biológica de Galicia. Methods and Results: Over a period of 2 years, the incidence and severity of downy mildew on the leaves and clusters of all 44 varieties was determined using a visual scale. Some of those examined showed high susceptibility (Chenin Blanc, Albariño and Prieto Picudo), others showed low susceptibility (Silveiriña, Caiño Bravo, Follajeiro and Brancellao Blanco), and still others showed intermediate susceptibility. Some varieties showed high disease incidence but low disease severity and vice versa. No significant correlation was detected between disease incidence and severity in either leaves or clusters, nor indeed between leaves and clusters. Neither berry colour, cluster compactness nor any other studied variable bore any clear relationship with susceptibility. Conclusion: The different grapevine varieties examined showed great variation in terms of their susceptibility to downy mildew. The susceptibility of most varieties was the same in both study years. Significance of the Study: The results of this work could help provide new material that might be of use in grapevine genetic improvement programs, and in the study of resistance to downy mildew. The selection of old varieties from the Iberian northwest may contribute towards the growth of organic viticulture in this area and even other winemaking regions around the world.     

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.     

Development of seed polyphenols in berries from Vitis vinifera L. cv. Shiraz

Polyphenols extracted from the seeds of Vitis vinifera L. cv. Shiraz berries were monitored during berry development. Initially seeds were green, plump and had pliable seed coats, but beginning at veraison the seeds browned in colour, became desiccated and the seed coats hardened. Isolated polyphenols consisted of flavan-3-of monomers ((+)-catechin, (-)-epicatechin and (-)-epicatechin-3-O-gallate) and procyanidins. The procyanidins were maximal in the 3 weeks prior to veraison, increasing little during this period. The amounts of flavan-3-ol monomers increased 5-fold during this same period of time, indicating that the procyanidins and the flavan-3-ol monomers accumulate at different stages. Beginning at veraison, amounts of all polyphenols declined and changed in composition. The decrease in amount followed second-order kinetics. Polyphenol changes after veraison could be explained by oxidation and therefore, electron paramagnetic resonance (EPR) spectroscopy was used to follow the potential development of radical species in the developing seeds. Spectra consistent with a phenoxyl radical were observed in the developing seeds. The concentration of radicals remained low until veraison but then increased, reaching a maximum three weeks later, declining slowly thereafter. Changes in radical intensity together with other documented changes in the seed are consistent with an oxidative event occurring during fruit ripening.     

Impact of node position and bearer length on the yield components in mechanically pruned Cabernet Sauvignon (Vitis vinifera L.)

Background and Aims: Bunch number per node or shoot varies significantly between seasons and is a major cause of yield variation. Varying total node numbers by pruning is the least expensive way to regulate yield. However, there is little information available on how varying bearer length (and thus node number) in a machine‐pruned canopy alters yield components. Methods and Results: The impact of bearer length on yield components was investigated in a mechanically pruned vineyard in Coonawarra, South Australia. Yield components were analysed according to the node position on the bearer at which the shoot arose. Both budburst and inflorescence number per node were highest at the distal node positions regardless of bearer length. When node positions two and three were located in the two most distal nodes made terminal by the pruning, they were significantly more fruitful than equivalent nodes on longer bearers. Shoots that arose from the two most distal node positions had the highest flower number per inflorescence and berry number per bunch. Conclusions: Budburst, and the number and size of the inflorescence and bunch were affected more by the node position at which the shoot occurred relative to the cut end of the bearer, than the position of the node from the base of the bearer. Significance of the Study: Our understanding of how pruning regimes impact on yield and how these pruning regimes may be modified to achieve a target yield has been improved.     

Recovery of anthocyanins from grape pomace extracts (Vitis vinifera L. cv. Cabernet Mitos) using a polymeric adsorber resin

Anthocyanins from a Cabernet Mitos grape pomace were extracted without sulfitation, purified and concentrated on a laboratory scale by adsorption to a styrene–divinylbenzene copolymerisate. The pigment loss during sample loading and washing of the column with water was negligible. Elution was performed with acidified methanol, ethanol and 2-propanol, respectively. The recovery rates ranged from 96 to 100% of anthocyanins when methanol was used, from 86 to 96% for ethanol and from 78 to 88% when pigments were eluted with 2-propanol. The temperature during adsorption and desorption (25 and 50 °C) did not significantly influence the pigment binding capacity. The recovery rates were not affected by the scale-up from laboratory to pilot-plant adsorption experiments. The use of polymeric resins facilitates nonthermal anthocyanin concentration since highly pigmented alcoholic eluates were obtained which can further be concentrated under mild conditions. The present study provides systematic data on adsorber technology increasingly used for the recovery of plant secondary metabolites.     

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).     

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.     

Stomatal density of grapevine leaves (Vitis vinifera L.) responds to soil temperature and atmospheric carbon dioxide

Background and Aims: Leaf stomatal density, i.e. number of stomata per unit area of leaf, is a primary determinant of the carbon and water relations of plants. However, little is known about the plasticity of grapevine stomatal density during leaf formation in response to environmental factors. In this study, we determined responses in stomatal density to soil temperature and atmospheric carbon dioxide during leaf development following dormancy to gain further understanding of grapevine carbon and water relations, and adaptation to climate change. Methods and Results: Using potted plants of Vitis vinifera (L.) cv. Chardonnay, we found that a period of soil warming from budbreak reduced stomatal density of concurrently formed leaves, whereas CO₂ depletion increased it. Furthermore, stomatal density of concurrently formed leaves was closely and inversely correlated with starch concentration in roots and trunks. Conclusion: We conclude that the stomatal density of grapevine leaves varies greatly in response to soil temperature and atmospheric CO₂ concentration. Significance of the Study: This is the first study to show that soil temperature influences stomatal density of plants. It also confirms that stomatal density of grapevines, like many other plants, responds inversely to atmospheric CO₂ concentration. Our findings demonstrate that stomatal density must be accounted for in any attempt to predict grapevine adaptation to climate change, and attendant impacts on CO₂ assimilation and water use efficiency in viticulture. More fundamentally, they indicate that the carbohydrate reserve status of perennial, deciduous plant species may be an important endogenous determinant of stomatal density.