Development of improved procedures for evaluating the smoke aroma potential of grapes exposed to forest fire smoke

暴露在森林大火烟雾中的成熟葡萄通常会产生消费者不能接受的令人不快的烟熏味/灰白色味道(或香味)。这种被称为烟雾污染的现象对加拿大的葡萄园和葡萄酒厂来说越来越成问题，因为它们通常位于容易发生强烈森林火灾的地区。考虑到被烟熏污染的葡萄酒可能造成的重大经济损失，显然需要风险评估策略，在发酵前(理想情况下，也是收获前)准确确定葡萄中烟熏味的强度。目前的检测方法采用一种名为气相色谱-质谱仪(GC-MS)的分析技术来检测已知有烟熏味道的化合物(如愈创木酚)的存在。尽管几家北美公司已经提供了基于GC-MS的烟雾污染测试，但这些测试的一个主要问题是，像愈创木酚这样的化合物经常储存在与各种糖有关的葡萄中。这些糖连接的烟味化合物既不能被GC-MS检测到，也不容易被味道或气味察觉到，然而，它们可能在发酵过程中被酵母释放出来，也可能是老化的。根据我们对葡萄/葡萄酒中其他风味化合物的监管知识，推测大多数烟熏味化合物作为糖键类似物储存在葡萄中。我们建议开发一种程序，通过这种程序，葡萄中与糖相连的烟熏味化合物可以在不经过发酵的情况下快速裂解，使现有的GC-MS方法能够检测到愈创木酚等化合物。迄今为止发表的文献中所报道的影响这种分裂的条件不适合用于准确的评估目的。我们改进的方法将允许我们的公司合作伙伴Sebastian Farm(Markanthony集团的一个葡萄园)在收获前评估葡萄的“烟熏香气潜力”，从而实现保险计划，并支持葡萄园内或酒庄内缓解策略的制定。该方法将与塞巴斯蒂安现有的烟雾污染评估提供商和研发设施完全兼容。

Ripening grapes exposed to forest fire smoke often yield wines that are characterized by an unpleasantsmoky/ashy flavor (or aroma) that is unacceptable to consumers. This phenomenon, called smoke-taint, isincreasingly problematic for Canada's vineyards and wineries since these are often located in regions prone tofrequent, intense forest fires. Given the potential for significant financial losses due to smoke-tainted wines,there is an obvious need for risk assessment strategies that can accurately determine the intensity of smokyflavor in grapes before fermentation (and, ideally, harvest). Current testing methods employ an analyticaltechnique known as gas chromatography-mass spectrometry (GC-MS) to test for the presence of compounds(like guaiacol) known to have a smoky flavor. Although several North American companies already provideGC-MS-based smoke-taint tests, a major problem with these tests is that compounds like guaiacol are oftenstored in grapes linked to various sugars. These sugar-linked, smoke-flavoured compounds are neitherdetectible by GC-MS nor are they easily perceptible by taste or smell, however, they maybe released by theyeast during fermentation and possibly ageing. Based on our knowledge of the regulation other flavourcompounds in grapes/wines, it is hypothesized that the majority of smoke-flavoured compounds are storedwithin grapes as their sugar-linked analogues. We are proposing to develop procedures by which thesugar-linked smoke-flavoured compounds in grapes can be rapidly cleaved, without fermentation, to enablecompounds like guaiacol to be detected by existing GC-MS methods. The conditions to effect such cleavagethat have been reported in the literature published to date are not suitable to be used for accurate assessmentpurposes. Our improved method will permit our company partner, Sebastian Farms (a vineyard in the MarkAnthony Group) to assess the "smoke-aroma potential" of grapes before harvest, enabling insurance planning,and supporting the development of in-vineyard or in-winery mitigation strategies. The method will be fullycompatible with Sebastian's existing smoke-taint assessment providers and R&D facilities.