Background and Aims The threshold for Botrytis contamination of winegrapes is not fully known. Using a measurement of the fungal sterol, ergosterol, we aimed to understand how much grey mould of grapes can be tolerated before there is a perceivable impact on wine sensory characteristics. Methods and Results Chardonnay grape bunches hand‐harvested in January 2016 from the Hunter Valley, NSW, were divided into one of five groups based on the visual assessment of the severity of grey mould using a scale of 0–4. Ergosterol analysis indicated that the fungal biomass of the five batches of grapes was 0.06, 0.28, 0.87, 1.50 and 4.25 g dry mass of fungus per kg wet mass. Grey mould infection resulted in an elevated concentration of benzaldehyde, 2‐pentyl furan, ethyl linoleate, (E)‐3‐hexenol, 3‐octanol, 1,5‐dimethyl‐naphthalene, 1,5‐dimethyl tetralin 1‐octen‐3‐ol, 1‐octen‐3‐one and 3‐octanone in the juice. 1‐Octen‐3‐ol, and 3‐octanone, ethyl‐3‐hydroxydodecanoate and isoamyl acetamide were elevated in wine made with Botrytis‐affected grapes. Sensory discrimination tests identified a difference between wine made from grapes with ≥0.87 g of dry mass of fungus/kg wet mass of grapes (equivalent to ≥2.57 mg ergosterol/kg grapes) and wine made from asymptomatic grapes. Conclusions Ergosterol correlated with the degree of grey mould contamination and the threshold in Chardonnay grapes was 0.28–0.87 g dry mass fungus/kg fresh mass of grapes. Significance of the Study Measurement of ergosterol has been evaluated as a quantitative estimate of the threshold for Botrytis contamination of winegrapes.

中文翻译：

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基于真菌甾醇麦角甾醇测量的霞多丽葡萄葡萄孢属菌群腐烂污染阈值

背景和目的 葡萄霉菌感染的阈值尚不完全清楚。通过对真菌甾醇麦角甾醇的测量，我们旨在了解在对葡萄酒感官特性产生可感知的影响之前可以容忍多少葡萄灰霉病。方法和结果 2016 年 1 月从新南威尔士州猎人谷手工采摘的霞多丽葡萄串，根据灰霉病严重程度的视觉评估，使用 0-4 的等级分为五组之一。麦角甾醇分析表明，五批葡萄的真菌生物量分别为每公斤湿重 0.06、0.28、0.87、1.50 和 4.25 克干重的真菌。灰霉菌感染导致苯甲醛、2-戊基呋喃、亚油酸乙酯、(E)-3-己烯醇、3-辛醇、1,5-二甲基-萘、1、果汁中含有 5-二甲基萘满 1-octen-3-ol、1-octen-3-one 和 3-octanone。1-Octen-3-ol、3-辛酮、3-羟基十二酸乙酯和异戊基乙酰胺在用受灰霉病影响的葡萄酿造的葡萄酒中升高。感官辨别测试确定了由真菌干重 ≥0.87 g/kg 葡萄湿重（相当于 ≥2.57 mg 麦角甾醇/kg 葡萄）酿造的葡萄酒和由无症状葡萄酿造的葡萄酒之间的差异。结论麦角甾醇与灰霉污染程度相关，霞多丽葡萄的阈值为0.28-0.87 g干重真菌/kg葡萄鲜重。研究的意义 麦角甾醇的测量已被评估为葡萄灰霉病污染阈值的定量估计。3-羟基十二酸乙酯和异戊基乙酰胺在用受灰霉病感染的葡萄酿造的葡萄酒中升高。感官辨别测试确定了由真菌干重 ≥0.87 g/kg 葡萄湿重（相当于 ≥2.57 mg 麦角甾醇/kg 葡萄）酿造的葡萄酒和由无症状葡萄酿造的葡萄酒之间的差异。结论麦角甾醇与灰霉污染程度相关，霞多丽葡萄的阈值为0.28-0.87 g干重真菌/kg葡萄鲜重。研究的意义 麦角甾醇的测量已被评估为葡萄灰霉病污染阈值的定量估计。3-羟基十二酸乙酯和异戊基乙酰胺在用受灰霉病感染的葡萄酿造的葡萄酒中升高。感官辨别测试确定了由真菌干重 ≥0.87 g/kg 葡萄湿重（相当于 ≥2.57 mg 麦角甾醇/kg 葡萄）酿造的葡萄酒和由无症状葡萄酿造的葡萄酒之间的差异。结论麦角甾醇与灰霉污染程度相关，霞多丽葡萄的阈值为0.28-0.87 g干重真菌/kg葡萄鲜重。研究的意义 麦角甾醇的测量已被评估为葡萄灰霉病污染阈值的定量估计。87 g 干真菌质量/kg 葡萄湿质量（相当于≥2.57 mg 麦角甾醇/kg 葡萄）和由无症状葡萄制成的葡萄酒。结论麦角甾醇与灰霉污染程度相关，霞多丽葡萄的阈值为0.28-0.87 g干重真菌/kg葡萄鲜重。研究的意义麦角甾醇的测量已被评估为葡萄灰霉病污染阈值的定量估计。87 g 干真菌质量/kg 葡萄湿质量（相当于≥2.57 mg 麦角甾醇/kg 葡萄）和由无症状葡萄制成的葡萄酒。结论麦角甾醇与灰霉污染程度相关，霞多丽葡萄的阈值为0.28-0.87 g干重真菌/kg葡萄鲜重。研究的意义 麦角甾醇的测量已被评估为葡萄灰霉病污染阈值的定量估计。