Skin color and chlorophyll absorbance: Indices for establishing a harvest date on non-melting peach

Abstract

The aim of this research was to develop an objective method to determine the best harvest date for non-melting peach cultivars. For this purpose the absorbance of chlorophyll (I-AD) on the skin of 'Andes Du-1', 'Loadel' and 'Bowen' peach cultivars was assessed. The on-tree fruit development was monitored for two consecutive seasons, one month before harvest. The correlation between I-AD of the skin and the flesh firmness was positive and highly significant (r=0.9). Also, I-AD and h degrees correlation was found to be positively and significantly associated (r = 0.75 to 0.91). The greatest observed correlations were between I-AD and flesh firmness, and the lowest correlations were between soluble solids concentration (SSC) and the other indices. The relationship between the h degrees of the skin and the h degrees of the flesh was high and significant, reaching r = 0.89, 0.84, and 0.88, for 'Andes Du-1', 'Loadel, and 'Bowen', respectively. However, the relationship between the two variables was not linear, so the data was adjusted to segmented regressions. The relationship between I-AD and the Munsell Book of Color defined the five categories of I-AD, ranging from less than 0.180 I-AD units for the category holding the ripest fruit (2.5Y 8/10) to the category of I-AD greater than 1.545 units (10Y 8/10) for the less ripe fruit. The I-AD has shown being an informative ripeness index for evaluating non-destructively the evolution of ripeness during the last phase on-tree, and particularly this index is associated with the flesh firmness. (C) 2015 Elsevier B.V. All rights reserved.