Changes in texture analysis parameters of wine grape berries at two ripeness stages: A study on varietal effect

Ripening of grapes is associated with great modifications at both the chemical and physical level. The aim of this work was to describe the changes in physical-mechanical parameters associated to ripening of wine grape berries, as evaluated by texture analysis, in order to understand if these modifications are stable across cultivars, or they are cultivar-specific. Berries from 21 different cultivars were sorted by flotation in different saline solutions, separated in two ripening stages differentiated by the amount of sugars (183 and 217 g L-1) and then analysed. Multivariate and univariate variations in texture analysis parameters were found, which were not constant across the studied grapevine varieties. However, a general behaviour was observed for skin weight, which had the largest variation between the two ripening stages. Other parameters showed significant differences between the ripening stages: skin thickness, berry gumminess, chewiness, and springiness, but the variation was not common to all cultivars. The work therefore evidenced the existence of cultivar-specific differences in the behaviour of physicalmechanical parameters between ripening stages.