Changes during the ripening of the very late season Spanish peach cultivar Calanda

Physiological maturity of peach at harvest greatly influences the post-harvest quality. Changes in colour during the last ripening stages of a very late and firm peach cultivar [Prunus persica (L.) Batsch cv. Calanda] have been studied to assess the feasibility of using reflectance colour references as non-destructive indices of maturity. The respiratory peak was simultaneous to the ethylene rise, and both induced important changes in the peaches. The physiological changes brought about a rise in polyphenoloxidase and peroxidase enzyme activity. The amount of carotenoids increased as maturity advanced and more markedly at the climacteric rise. Reflectance spectra and CIELAB coordinates reflected changes in skin and pulp colour and a* and hab evolved nearly in a near linear way. Values of the b* coordinate show changes as well. These findings agree with and extend previous results that reflectance changes can be used as reliable indices to establish the time of physiological maturity in Calanda peaches.