Brown Marmorated Stink Bug Taint in Pinot noir: Detection and Consumer Rejection Thresholds of trans-2-Decenal

Abstract

Brown marmorated stink bug contamination in grape clusters results in the addition of an aroma compound, trans-2-decenal, in wine. Described as a green, musty aroma, it is considered detrimental to wine quality. The main focus of this study was to estimate the detection and consumer rejection thresholds of trans-2-decenal in Pinot noir, determine its impact on wine quality and explore potential consumer segmentation. Thresholds were measured using an ascending forced choice method of limits applied to a series of triangle and paired comparison tests. Thresholds were estimated by a psychometric function with significance based on binomial distribution as well as dʹ values based on Thurstonian models. The method of quantification resulted in different threshold levels. The detection threshold of the panel was estimated to be 0.51μg/L from a psychometric fit and between 1.92 and 4.80μg/L based on Thurstonian scaled values. Similarly for consumer rejection threshold, psychometric function resulted in a threshold of 13μg/L and dʹ values between 4.80 and 12.00μg/L. Wine containing trans-2-decenal above consumer rejection threshold was described as green, musty and less fruity by wine professionals. When potential consumer segmentation was explored, based on the detection and consumer rejection threshold data, there was no direct link between sensitivity and preference. Based on such findings, the use of consumer rejection threshold is recommended when establishing consumer tolerance levels of trans-2-decenal in wine. Additionally, the use of d’ which provides a more sensitive method of threshold estimation seems more appropriate for compounds that negatively impact wine quality, such as trans-2-decenal.