Harvest index for mechanically handled peach fruits in post-harvest

The aim of this study was to define harvest indexes, based on peach skin ground color, suitable to allow mechanical grading and reach at the same time high fruit quality. Two cultivars, 'Springbelle' and 'Douceur', were included in this research. In the first year of the study, harvest was performed in three pickings, fruit samples were graded with a mechanical sizer, and divided into seven categories based on their ground skin color, measured with a colorimeter. On the same fruit, soluble solids content, titratable acidity, and flesh firmness were measured. Moreover, the evaluation of damage eventually caused by grading and organoleptic tests were performed. These data were used to define harvest indexes based on the a* coordinate of skin ground color. The harvest indexes obtained during the first year were used as harvest index in the second year of the trial to test their suitability. The results showed that the method can be used successfully depending on the cultivar. Indeed, the model seems to work better on 'Springbelle', whereas skin ground color did not correlate with the qualitative characteristics and the ripening level of 'Douceur'.