Australian Journal of Grape and Wine Research最新文献

Background and Aims. Smoke exposure occurred in the Adelaide Hills region in December 2019 due to a wildfire, when wine grapes were peppercorn-size green berries. Previously, pre-veraison smoke exposure had been identified through model experiments as unlikely to affect grape composition, whereas smoke exposure after veraison can have a major effect on wine flavour. Hence the effects of pre-veraison smoke on grape and wine composition, and smoky sensory properties of wine were investigated. Methods and Results. Chardonnay, Pinot Noir and Shiraz were investigated and eight blocks with varied smoke exposure were selected for each cultivar. Berries were sampled initially four weeks after the fire and at harvest, and mature grapes were made into unoaked wines. Established smoke exposure markers, phenolic glycosides, were found in berries at pre-veraison and at harvest from the high smoke exposure sites, with concentrations well above those found in non-smoke exposed fruit. Volatile phenols were also elevated in grapes at harvest. The resulting red wines from some exposure vineyards were high in volatile phenols, glycosides and smoky flavours. However, most of the Chardonnay wines expressed much less smoky flavours, despite similar levels of smoke exposure of grapes. Conclusions. Pre-veraison smoke exposure can result in elevated concentrations of volatile phenols and their glycosidic metabolites in grape berries and wine and cause strong smoky flavour in wine. Significance. The wine sector and land management agencies responsible for controlled burns need to consider the effect of smoke from fires near vineyards even very early in the growing season.

Background and Aims. If bioprotection has already been proven to limit the development of spoilage flora on musts, its effectiveness against oxidation depends on the winemaking process. To optimize its application, this study analyzed the evolution of the chemical composition of the bioprotected musts and wines, according to different settling routes. Their impacts on the organoleptic characteristics of wines were also studied. Methods and Results. A bioprotected must was subjected to 6 different maceration routes before AF (triplicates), varying the duration and temperature parameters. A temperature value ≤12°C was the main factor independently of the duration which allowed a good implantation of the bioprotectant. An increase of the maceration duration at 12°C led to browning of the must, without significant effect on the final color of the wine, which was felt as more “floral,” with more length in the mouth. Conclusions. The bioprotectant implantation and its effectiveness on the sensory profile of the wine was guaranteed at maceration temperature values lower than 12°C. Significance of the Study. This study participates in the improvement of the bioprotection management in white winemaking, with the guarantee of a positive impact of the prefermentation maceration without sulphites on the organoleptic profile of the wines.

Background and Aims. This research investigates spatial and temporal trends in budburst timing across Australian wine regions from 1910–2019. The potential drivers of these observed trends were then identified, including anthropogenic climate change and large-scale climate drivers (El Nino–Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), and Southern Annular Mode (SAM)). Methods and Results. The timing of budburst was approximated using accumulation measurements applied to Australia wide gridded temperature data. We show that the modelled budburst date has been gradually shifting to earlier in the year for most (95%) Australian wine regions, at an average rate of one day every 24 years. This linear trend in budburst timing is likely to be associated with steadily increasing air temperatures due to anthropogenic climate change. Significant interannual variability was also observed and was correlated with IOD and SAM; however, no significant relationship was found with ENSO. Positive IOD phases result in budburst occurring on average four days earlier than the long-term average; however, this can be as high as eight days. Conclusions. The results of this study highlight that budburst timing for wine grapes is not a stationary phenomenon and is influenced by both natural and anthropogenic conditions. Significance of the Study. Understanding variability and trends in modelled budburst timing will assist tactical and strategic management practices and improve phenological modelling and adaptation planning for climate change.

Background and Aims. In viticulture, one of the effects of warming trends is the advance of budburst date and the consequent increased risk of spring frost-related damage. In 2021, severe frost events affected a large fraction of European viticulture. In a cv. Barbera vineyard, located in NW Italy, primary bud shoots (PBS), secondary bud shoots (SBS), and suckers (SK) were tagged after the occurrence of freezing temperatures in spring. The goal of the study was to clarify if SBS could partially restore yield loss and analyze their contribution to fruit composition. Methods and Results. The number of developing SBS and SK correlated with the number of killed PBS. While PBS bore 1.44 inflorescences per shoot, SBS had much lower fertility (0.4), with SK at intermediate levels (0.85). The vine yield was 40% of the previous season, with SBS bunches contributing just 17% of the total. SBS produced smaller and looser bunches, as compared with PBS (−28% mass and −27% compactness). At harvest, no difference was found in grape total soluble solids (TSS) among different shoot types. However, the TSS average was notably higher than that observed in the previous season (27.8°Brix vs. 23.3°Brix in 2020). Interestingly, while in PBS and SK, a direct correlation (linear and quadratic, respectively) existed between the leaf area to yield ratio (LA/Y) and grape TSS or total anthocyanins, this did not occur for SBS. Conclusions. In the case of spring frost damage, the number of PBS avoiding fatal injuries will drive agronomic results at harvest since SBS contribution to total yield is modest due to low shoot fruitfulness. The frost-induced increase in vine LA/Y leads to a dramatic rise in grape TSS and phenolics. Significance of the Study. When spring frosts kill a significant number of primary shoots, an altered grape composition at harvest should be expected due to changes in vine balance. Therefore, the vineyard management should be adjusted accordingly early in the season. Further studies are needed to test specific post-frost canopy management strategies ensuring yield, optimal fruit composition, and cane renewal.

Background and Aims. The composition of grapes (Vitis vinifera L.) at harvest is a key factor that determines the future quality of wine. The work aimed to evaluate and compare the environmental impact of the most evaluated technological parameters using three approaches: the wet-chem method, the optical method using benchtop devices, and the optical method using a prototype smart and cost-effective device (Technology Readiness Level: 5). Methods and Results. The life cycle assessment (LCA) methodology was used to identify the most environmentally sustainable solution in a “from-cradle-to-grave” approach. The functional unit was identified by the execution of the analyses necessary to measure the three technological parameters: TSS, pH, and TA. The findings show that the optical analysis carried out with the prototype is the most suitable and green solution (i.e., with the lowest environmental impact in all the impact categories analysed); in fact, the same technology has proved to be 3.2 times more sustainable than the wet-chem method for the best average environmental performance. Conclusions. The research demonstrated the environmental impact advantages of the optical analyses for assessment of grape composition. Significance of the Study. Innovations in agriculture and the development of smart solutions represent advantages for managing and monitoring the composition of agri-food products that are a green solution for the industry.

Background and Aims. Fumonisins are a group of mycotoxins produced by some isolates of black aspergilli. This study examines the dynamics of fumonisins during winemaking and storage and the role of fining agents in the removal of FB2, the most prevalent fumonisin produced by black aspergilli. Methods and Results. Chardonnay grapes were inoculated with a fumonisin-producing strain of Aspergillus welwitschiae and fumonisins were quantified at different stages of vinification. The stability of fumonisins was studied at 13 and 25°C using Chardonnay wine spiked with FB2. Activated charcoal, calcium bentonite, yeast hulls, and a nonallergenic polysaccharide of nonanimal origin (NO (OX)) were evaluated as fining agents for FB2 removal from wine. Fumonisins were quantified by LC-MS/MS. During vinification most of the fumonisins were removed with the solids, with only 3% of the fumonisins found in the grapes being transferred to the wine. Fumonisin FB2 was stable in white wine for at least 4 months, but was reduced by 42% after 8 months at 25°C. Activated charcoal and bentonite were able to remove more than 80% of FB2 in white wine. Conclusions. Vinification can lead to the partial removal of fumonisins. The use of fining agents and wine storage leads to further reduction. Significance of the Study. This study demonstrates the fate of fumonisins during vinification and wine storage and the potential use of fining agents for amelioration of fumonisin contamination.

Background and Aims. Rosé wines are becoming more popular, as is the demand for organic wines. However, there are few studies on the effects of operative choices on the quality and style of these wines. The paper aims to investigate the effects of the early stages of processing (destemming/crushing and pressing) on rosé wine characteristics. Methods and Results. A full factorial experiment was carried out on Sangiovese, considering two factors related to grape processing: the prepressing treatment (intact clusters or destemmed/crushed berries) and the pressing pressure. Sugars, ethanol, acidity, phenols, and color were measured in juices, while volatile compounds and sensory profiles were evaluated in wines. Destemming/crushing dramatically changed the composition of both juices and wines’; notably, acidity increased and floral and color intensities decreased in intact cluster samples. Furthermore, a clear interaction was found between prepressing treatment and pressure. Pressure, in turn, affected several acidity and color parameters. This could be related to the chemical composition and consistency of the different berry zone, which interact with the mechanical action of the destemmer/crusher and press. Conclusions. Processing choices affect all of the main qualitative features of rosé wine; they could be successfully used to decide the wine’s style and minimize the use of additives and adjuvants. Significance of the study: in rosé production, the capability to modulate the operational protocols allows selecting of different wines from the same grape batch. This represents a useful tool to optimize grape processing according to the company’s commercial priorities.

Background and Aim. The genetically determined characteristics of grapevine rootstocks are important factors that affect scion performance. This 3 years’ field study aimed to characterize the influence of four well-established 30-year-old rootstocks (110 Richter, 1103 Paulsen, 41B, and 161-49Couderc) on the Tempranillo cultivar in the semiarid wine growing region of D.O.Ca. Rioja, North-Eastern Spain. Methods and Results. Nutrient concentrations of mineral elements at flowering and veraison were determined in the vines, jointly with grapevine-water status, gas exchange, vine vigour, and chlorophyll content. Moreover, grapevine yield and grape quality were determined at harvest. The least vigorous rootstocks (41B, 161-49C) conferred drought adaptability traits by increasing water use efficiency (WUE) and decreasing whole-plant water conductance per unit leaf area (K_plant) compared to the more vigorous rootstocks (1103-P, 110-R). In contrast, the more vigorous rootstocks increased water transport capacity, which led to higher plant performance and nutrient uptake efficiency. At flowering, 1103-P and to a lesser extent, 110-R were most efficient at taking up nutrients, while 161-49C had the lowest concentrations for most nutrients. At veraison, 41B exhibited closer behaviour to 110-R than 161-49C, while 1103-P and 161-49C remained the most differentiated rootstocks, with higher and lower nutrient uptake, respectively. In addition, compared to the more vigorous rootstocks, the yield was up to 1.6 kg lower for the less vigorous rootstocks but the grape composition was improved. Notably, 161-49C led to higher total soluble solids, total acidity, and polyphenol content. Conclusions. Overall, grafting onto specific rootstocks represents a strategy to confer differential regulation of grapevine water-saving strategies, yield, berry quality, and nutrient uptake potential. Significance of the Study. This information may be useful for growers seeking to develop a site-specific selection of rootstocks for the grafted Tempranillo cv.