Understanding novel germplasm solutions: sensory, chemical and preliminary hedonic insights of wines made from Australian first-generation mildew resistant cultivars

Abstract

One of the major issues for wine production in Australia is the management and eradication of powdery and downy mildews and the associated yield losses they present, costing Australian grape growers upwards of AUD$160M per annum [1]. One solution is the development of resistant varieties such as pilzwiderstandsfähig (PIWI) or fungal-resistant varietals. PIWI varieties see acceptance by some consumers in European countries (e.g., Germany, France) when informed of their environmental benefits [2, 3], yet wines continuously display negative sensory and chemical properties, affecting wine quality and requiring specific procedures to rectify these defects [4-6]. These issues may discourage Australian consumers due to established preferences for wine products [7]. CSIRO has also developed new wine cultivars with mildew resistance [1]. These First-Generation Disease-Resistant (FGDR) grapevines contain ~99% Vitis vinifera DNA[8, 9], possibly alleviating the challenges associated with PIWI varietal flavour profiles. This study aims to evaluate the sensory and chemical properties of FGDR grapevines developed in Australia. The study uses wine made from 8 white and red FGDR varieties, developed using six different pollen donors (Frontignac, Verdelho, Muscat Gordo Blanc, Riesling, Dunkelfelder, and Tannat), across three vintages (2019-21). Varieties were grown on the same plot in Irymple, Victoria, undergoing identical, small-batch winemaking protocols. Control wines (Chardonnay, Riesling, Shiraz and Cabernet Sauvignon) also came from the same plot. Rate-All-That-Apply was conducted on wines to generate sensory profiles, using consumers between 18 and 65 who regularly consume white and red wines. Fifty participants individually assessed wines randomly: rating liking on a 9-point scale followed by intensity of applicable sensory attributes. Untargeted volatile chemical analysis of each wine was conducted in triplicate using GCMS, semi-quantifying compounds by relative peak area using an internal standard. Two-way ANOVA helped determine key wine sensory drivers, visualised using PCA. Preliminary hedonics suggest that Australian consumers significantly preferred FGDR wines compared to controls, with results identifying sensory and chemical drivers of liking. Wines of the same parentages tended to group together in the PCA, indicating consistency in flavour profiles across vintages in most cases. CVA showed that the wines have different flavour profiles that would suit varying consumer tastes.

References

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