Peach fruit growth, development, ripening and postharvest physiology

Shape and size at harvest are important quality parameters of peaches. After ovule fertilization, the typical double-sigmoid growth pattern is affected and regulated by both genetic and intra- and inter-organ competition for assimilates. Appropriate thinning strategies are crucial in order to obtain bigger and better fruit at the end of development when the ripening syndrome occurs. Peaches are climacteric fruit and, as well as changes in respiration and ethylene production, the main quality-related processes occurring at ripening are the loss of flesh firmness, turnover of the flesh and skin colour, and the changes in taste and overall flavour due to the increase in mono- and disaccharide concentrations, the biosynthesis of volatile compounds and the decrease in organic acids. Refrigeration is widely applied to delay postharvest ripening and prolong the shelf life of peaches. Several metabolic changes occur during cold storage, some of which are related to the development and appearance of chilling-injury symptoms.