Grape smoke exposure risk assessment: Wine matrix impact on smoke marker compound smoke expression

Abstract

During wildfires large amounts of volatile phenols (VP’s) are released into the air from wood burning. These compounds absorb through the berry skin, where they are quickly glycosylated. Studies have shown that both the free and bound volatile phenols contribute to smoke taint perception. For grape smoke exposure risk assessment, both the natural amount of free and bound VP’s in grapes (baseline) as well as rejection threshold levels of these compounds in different wine matrixes need to be determined. In the current study the sensory attributes of different smoke impacted and non-smoke impacted wines from the same sites were determined by descriptive analysis. Multivariate statistics were used to relate smoke-related sensory attributes to smoke marker compounds. Subsequently, wines with different levels of smoke marker compounds were made by serial dilution of a smoke impacted wine with its respective non-impacted wine. A consumer study was conducted to determine the change in ‘liking’ for a wine depending on the percentage inclusion of smoke impacted wine. Rejection threshold levels of smoke marker compounds in red wine matrixes were determined by linking ‘liking’ scores to specific wine attributes. This is the first step in creating clear guidelines for wine smoke taint risk assessment.