Metabolite analysis, environmental factors, and a transgenic approach to understanding strawberry (Fragaria x ananassa) flavor

Fresh strawberries (Fragaria x ananassa) are valued for their red color, juicy texture, distinct aroma, and sweet fruity flavor. To ensure continued consumption, flavor must be high in quality, but defining this complex trait has proven to be difficult. This work presents a metabolite perspective on the perception, variation, and alteration of strawberry fruit flavor to increase consumer acceptability.;In the primary study, genetic and environmentally induced variation among strawberry is exploited by simultaneously assaying fruit for: inventories of volatile compounds, sugars, and organic acids; physical measures of titratable acidity, soluble solids content, and firmness; and consumer hedonic and sensory responses. Psychophysics analysis determines seasonal effects and fruit attributes influencing hedonics and sensory perception of strawberry fruit.;Seasonal progression negatively influences soluble solids content, primarily through sucrose, leading to decreased volatile content. These alterations are perceivable because sweetness intensity, flavor intensity, and texture liking significantly influence overall liking through variations in sugar concentrations, volatiles, and firmness. Specific aroma volatiles make contributions to perceived sweetness independent of fruit sugar concentration. Volatiles that increase perception of sweetness without adding sugar will have far-reaching effects in food chemistry, and also provides targets for future breeding efforts of consumer defined traits.;The biosynthesis of an underrepresented volatile in commercial germplasm, methyl anthranilate, is the target of genetically engineering Petunia x hybrida 'Mitchell Diploid' and 'Strawberry Festival'. Expression of Zea mays ANTHRANILIC ACID METHYL TRANSFERASE 1.1 will hypothetically enhance its aroma or flavor. Petunia flowers with expression emit methyl anthranilate at levels similar to Fragaria vesca. Expression is confirmed in over twenty T0 lines of 'Strawberry Festival'. Consumer panels assaying petunia and strawberry with methyl anthranilate phenotype will assist in assaying this volatiles influence on perception.;Metabolite inventory of diverse strawberry fruit coupled with consumer panels identifies rare and important compounds associated with strawberry flavor. Transgenic efforts will determine methyl anthranilate influence on consumers. Furthermore, exploration of environmental manipulation provides some prospective technologies for altering strawberry volatile profiles. Whether through breeding, transgenics, or environmental manipulation increasing the flavor of strawberry will ensure the current trend of increasing consumption of this highly nutritious food.