2014 ASHS Annual Conference

The most important flavor compounds in strawberry fruit are sugars, organic acids and volatiles. Previously volatiles were thought to merely provide aroma and to create flavor when integrated with the tastes evoked by sugars and acids.  However, recent analyses suggest that volatiles can contribute to sweetness as well. The objective of this study was to determine whether certain volatiles affect panelists’ perceptions of sweetness and flavor intensity independently from the amount of total sugars (TS) and titratable acidity (TA) in strawberry fruit. This work builds on a previously published study by fitting more comprehensive statistical models to the data.  Fifty-four samples from 34 genotypes were harvested across 12 evaluation dates during the 2010-11 and 2011-12 strawberry growing seasons in west-central Florida. An average of 105 panelists per evaluation rated sweetness and flavor intensity of the fruit using a hedonic general labeled magnitude scale from 0 to +100. At each evaluation subsamples from each genotype were kept to quantify volatiles as well as TS and TA. Sweetness and flavor ratings were regressed against first and second order terms of TS and TA, including the first order interaction. After eliminating non-significant terms from these two models, each volatile was introduced one at a time to estimate one regression line per volatile for sweetness and one regression line per volatile for flavor. Sweetness and flavor ratings increased linearly with TS. While TA did not affect sweetness, its first and second degree terms were highly significant for flavor intensity. Out of the 81 volatiles quantified across all samples, 19 affected sweetness (ten positively and nine negatively) and 17 affected flavor ratings (ten positively and seven negatively). Only 12 volatiles affected both sweetness and flavor ratings, seven positively and five negatively. Three of these seven volatiles with positive effect had large standardized coefficients, a measure of their relative importance when compared to the magnitude of the other coefficients within each model. Their size represented between 22% and 26% of the TS coefficient in sweetness models and between 32% and 43% in flavor models. Two of the five volatiles that detract from sweetness and flavor also stood out. Both coefficients represented 24% of the TS coefficient in sweetness models and 31% and 33% in flavor models. Breeders can target these compounds to increase consumers’ acceptance of new cultivars and perhaps to increase sweetness perception without increasing sugar content.