PEACH TEXTURE DURING RIPENING AFTER EXTENDED STORAGE¹

Abstract

Peach texture during storage is affected by temperature, humidity, and oxygen level. Four cultivars, 'Sentinel', 'Topaz', 'Parade ' , and (Fairtime', were stored at OC for 28 days after which time texture tests were done for the next four d q s during the peach's ripening at 25C. A cylindrical peach specimen was penetrated with a wire probe installed in an Instron universal testing machine. From the force-displacement response, firmness parameters were determined and a fast Fourier transform frequency analysis was performed to determine the jaggedness of the curves. Effegifirrnness, Instron peak force, and spectrum area changed the most during ripening. The lowest@equency ratio (0 to 0.19 Hz) changed more than any other fiequency ratio during ripening. Significant decreases in Effegi firmness and in Instron peak force, steady state force, andfrequency ratios were observed between the first and the second day of ripening but the changes were not signlfiCant thereafter. Afer one day of ripening, late season cultivars [Fairtime' and 'Parade' were significantly less firm than 'Topaz ' . Most parameters indicated that 'Sentinel' an early season cultivar, was firm like 'Topaz ' , a mid-season cultivar. After two days, differences in firmness parameters among the four cultivars were not signrficant.