Volatile analysis of Botrytis contaminated grapes using headspace solid phase microextraction GC-MS

Abstract

Grapes infected with grey mould due Botrytis cinerea are widespread in vineyards during certain growing conditions.  Excessive infection levels may lead to decreased yields and the formation of off flavours in wine made from infected grapes. To assist in timely vineyard management that minimises yield and quality losses, decision support tools that correlate early detection of Botrytis infection and quantification of potential off flavour development is desirable.In this study, laboratory infection of whole bunches/ single berries with Botrytis cinerea to create a range of grey mould contamination in Shiraz, Cabernet Sauvignon, Chardonnay and Semillon were undertaken. After SPME GC-MS detection of grape homogenate, 8 out of 22 volatile compounds, including 3-octanol, 3-octanone, 1,5-dimethylnapthalene and 1,5-dimethyltetralin, were identified from VIP score and selectivity ratio, and excellent predictive model of Botrytis cinerea infection levels (determined by ergosterol measurement, antigen capture and qPCR) were developed using PLS and PLS2. These compounds, with high predictive accuracy, could be considered as potential biomarkers for rapid MS techniques in early stage.