Angelica Iobbi is pursuing her Ph.D. under the supervision of Dr. Elizabeth Tomasino at Oregon State University. She is a Food Scientist and her work investigates the cause of fruity aromas in white wine. Her current studies involve the adaptation of a novel sensory methodology, identification of esters, monoterpenes and volatile thiols using the GC and HPLC, and the effects of specific aroma families to tropical fruit aroma causation. She has a passion for flavor chemistry and seeks to work as a food and flavor developer.
“The role of esters and thiols in white wine and their interaction in the formation of tropical fruit aroma”
White wines are typically characterized by their fruity aromas, which are important for wine quality and consumer acceptance. Volatile thiols are impact aroma compounds, well-known for imparting tropical fruit aromas such as mango, passion fruit, and guava in wine. Although there is scientific evidence that thiols cause tropical fruit aromas, this is not the complete story. They must be in combination with other fruity aroma compounds, such as esters, to produce tropical fruit aromas in wine. Therefore, the objective of this study was to investigate the interaction effects of esters and volatile thiols to the fruitiness profile of white wine. A Pinot gris wine was produced at the OSU research winery and was dearomatized using Lichrolut® EN resin. 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 esters. Samples were subjected to sensory analysis where fifty-one white wine consumers evaluated the orthonasal aroma of the wines and participated in check-all-that-apply (CATA). Results were analyzed using Correspondence Analysis (CA). Volatile thiols contributed to earthy, green, and non-tropical fruit aromas. Overall, tropical fruit aromas were only detected in treatments where combinations of esters and esters + thiols were present, showing that esters themselves and esters + thiol combinations are important for tropical fruit aroma formation in white wine. This study showed that there is an interaction effect between esters and thiols to form tropical fruit aroma in white wine. In addition, esters caused tropical fruit aroma without the presence of thiols. This study emphasized the importance of studying the interactions that occur between aroma compounds in the wine to better understand aroma causation. As a next step, we will test different combinations of esters present in white wines to evaluate their fruitiness profile.