Non-destructive determination of 'Big Bang' nectarine quality and harvest maturity

In nectarines, potential shelf life and quality at consumption are closely related to the ripeness stage of fruit at harvest. Usually, the harvest is based on color, firmness, sugar and acids content of fruit, although these determinations are carried out through destructive methods and in a limited number of samples. The technique of Vis/Nir spectroscopy is used for the development of a non-destructive index based on the difference of absorbance (I-DA) between two wavelengths near the absorption peak of chlorophyll-a, and it allows monitoring of changes in ripeness processes directly in the field. The objective of this paper is to track changes in quality that occur during nectarine ripeness of 'Big Bang' cultivar and their relationship with non-destructive indexes obtained with the DA-Meter equipment. The research was conducted in 2016 and 2017, on 'Big Bang' yellow flesh nectarine harvested from 22 trees, grafted on GF 677 rootstock, grown in a commercial orchard located in Basilicata (Italy). Fruits were weekly monitored for the evolution of the IDA index from April to June, directly in the field. In this cultivar, the IDA index showed a significant linear correlation with the quality parameters, throughout the period of harvest, appearing a promising index to assess the ripeness and the quality of peaches directly in the field.