Uneven distribution of flavour components in tablegrape berries

Abstract

Background and Aims The basic taste of grapes is determined by the sugars, acids and their ratio while the cultivar flavour results from its unique profile of volatile compounds. So far, the general perception is that flavour components are evenly distributed in grape berries. In the current study, the composition of TSS, titratable acidity (TA) and volatiles was examined in the stem and stylar ends of tablegrapes. Methods and Results Values of TSS were up to 2°Brix higher, and TA values were up to 1.5-fold higher in the stylar end compared with that in the stem end of the berries. Coating the berries at veraison with wax to reduce evaporation decreased TSS accumulation and the stem-end versus stylar-end difference in TSS and TA. Volatile concentration differed significantly in berry tissues in an opposite pattern being higher in the stem than in the stylar ends of the berries. Conclusions Our findings indicate that there is a substantial difference in the composition of the stem and stylar end of tablegrape berries. It is also suggested that transpiration may play a role in the uneven distribution. Significance of the Study These results are novel for tablegrapes and are likely to contribute significantly to the understanding of flavour accumulation in grapes.