Abstract

Due to the absence of an objective methodology to assess berry firmness in table grapes, a study using two devices, Firmtech 2® and torque meter Torque Load Sensor®, was conducted on Flame Seedless, Superior Seedless, Red Globe, Thompson Seedless and Crimson Seedless cultivars grown in the central region of Chile. Grape clusters were collected according to firmness, differentiating among three categories: FC, firm cluster; MFC, medium firm cluster, and SC, soft cluster. Berry firmness (g/mm) was assessed using Firmtech 2® (all berries in the cluster), whereas flesh firmness (N-cm) was measured with Torque Load Sensor® (using a representative sample from the upper, middle and distal parts of the cluster). Additionally, the correlation was determined between Firmtech 2® and Durofel®. Results indicate significant differences among the three cluster types (FC, MFC and SC) in all cultivars, except for Superior Seedless where only FC and SC could be differentiated from each other. The correlation between firmness measured with Firmtech 2® and with Durofel® is high and significant (r = 0.76). Berry firmness is a measurable parameter and would therefore allow sorting the different table grape cultivars into firmness ranges or categories.