Tropical fruit aroma in white wines: the role of fermentation esters and volatile thiols

Abstract

Volatile thiols are impact aroma compounds, well-known in the literature for imparting tropical fruit aromas such as passion fruit, guava, grapefruit, and citrus in white wines [1]. More recent evidence suggests that tropical fruit aromas are also caused by other aroma compounds besides thiols, such as fermentation esters, or the interaction between these volatile families. Therefore, the objective of this study was to investigate the effects of combining esters and/or thiols to determine their impact on the fruitiness aroma perception of white wines. Pinot gris wine was produced at the OSU research winery and was dearomatized using Lichrolut® EN. Combinations of fermentation volatile compounds were added to the wine, forming the aroma base. Treatment wines were composed of additions of different concentrations and combinations of thiols and/or esters. Samples were subjected to sensory analysis where forty-six white wine consumers evaluated the orthonasal aroma of the wines and participated in Check-All-That-Apply (CATA). Following the results obtained by CATA, samples were subjected to a Sensory Descriptive Analysis (SDA) panel where 13 trained panellists evaluated the intensity of the most used aroma attributes elicited by consumers. Thiol treatments without the presence of esters contributed to earthy and grassy aromas. Overall, tropical fruit aromas were detected in the several treatments containing esters and esters + thiols. Differences in the intensity of the aroma attributes were observed as well . This study showed that esters and thiols are necessary for tropical fruit aroma causation in white wines. Therefore, grape growers and winemakers should adapt viticultural and winemaking conditions to increase the concentrations of both aroma families and therefore enhance the tropical fruit aroma perception in white wines.