Life Sciences Institute, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, 5612 Pisa, Italy.
Department of Wine Science, Waite Research Institute, The University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia.
Molecules. 2021 Mar 23;26(6):1798. doi: 10.3390/molecules26061798.
When bushfires occur near grape growing regions, vineyards can be exposed to smoke, and depending on the timing and duration of grapevine smoke exposure, fruit can become tainted. Smoke-derived volatile compounds, including volatile phenols, can impart unpleasant smoky, ashy characters to wines made from smoke-affected grapes, leading to substantial revenue losses where wines are perceivably tainted. This study investigated the potential for post-harvest ozone treatment of smoke-affected grapes to mitigate the intensity of smoke taint in wine. Merlot grapevines were exposed to smoke at ~7 days post-veraison and at harvest grapes were treated with 1 or 3 ppm of gaseous ozone (for 24 or 12 h, respectively), prior to winemaking. The concentrations of smoke taint marker compounds (i.e., free and glycosylated volatile phenols) were measured in grapes and wines to determine to what extent ozonation could mitigate the effects of grapevine exposure to smoke. The 24 h 1 ppm ozone treatment not only gave significantly lower volatile phenol and volatile phenol glycoside concentrations but also diminished the sensory perception of smoke taint in wine. Post-harvest smoke and ozone treatment of grapes suggests that ozone works more effectively when smoke-derived volatile phenols are in their free (aglycone) form, rather than glycosylated forms. Nevertheless, the collective results demonstrate the efficacy of post-harvest ozone treatment as a strategy for mitigation of smoke taint in wine.
当林火发生在葡萄种植区附近时，葡萄园可能会暴露在烟雾中，并且根据葡萄藤暴露在烟雾中的时间和持续时间，果实可能会受到污染。烟雾衍生的挥发性化合物，包括挥发性酚类化合物，会给受烟雾影响的葡萄制成的葡萄酒带来不愉快的烟熏、灰烬特征，导致在葡萄酒明显受到污染的情况下，收入大幅损失。本研究调查了采后臭氧处理受烟雾影响的葡萄以减轻葡萄酒中烟雾污染强度的潜力。在大约转色期后 7 天和收获时，将梅洛葡萄藤暴露在烟雾中，然后在酿酒前，用 1 或 3 ppm 的气态臭氧分别处理 24 或 12 小时（分别）。在葡萄和葡萄酒中测量烟雾污染标记化合物（即游离和糖苷化挥发性酚类化合物）的浓度，以确定臭氧处理在多大程度上可以减轻葡萄藤暴露于烟雾的影响。24 小时 1 ppm 臭氧处理不仅显著降低了挥发性酚类化合物和挥发性酚糖苷的浓度，而且还降低了葡萄酒中烟雾污染的感官感知。采后烟雾和臭氧处理葡萄表明，当烟雾衍生的挥发性酚类化合物处于游离（苷元）形式而不是糖苷形式时，臭氧的作用更有效。尽管如此，综合结果表明，采后臭氧处理是减轻葡萄酒中烟雾污染的一种有效策略。
