Consumer rejection threshold of ethyl phenylacetate and phenylacetic acid, compounds responsible for the sweet-like off odour in wines made from sour rotten grapes

Abstract

Backgrounds and Aims: This study aimed to determine a consumer rejection threshold (CRT) for ethyl phenylacetate (EPhA) and phenylacetic acid (PhAA) in wine. These compounds have recently been reported to be responsible for sweet-like, honey off odours in wine made from sour rotten grapes.

Methods and Results: Non-expert wine consumers (n = 35) received pairs of samples comprising a control wine against a spiked wine with an ascending concentration of the target compounds and were asked to indicate which sample they preferred. Results estimated a conjoint CRT for EPhA and PhAA of 140 and 700 µg/L, respectively. Wines spiked with a EPhA and PhAA concentration around the CRT evoked intense ‘dried fruit’ aromas that led to a decrease of the general aroma quality; these wines are significantly rejected by consumers.

Conclusions: The measured CRT provides an initial estimation of the risk concentration for EPhA and PhAA in red wine, as they represent a ‘taint’ for regular wine consumers.

Significance of the Study: These data allow wine producers to predict if a given wine will be disliked by consumers or to help guide ‘blending away’ of such wines.