Biochemical parameters for the evaluation of different peach flesh types

The features of quality in peach fruits include both organoleptic and postharvest traits. Flesh texture is one of the main peach quality parameters and different flesh phenotypes have been described: the melting (M), with a range of firmness from very low to very firm (MVF), the stony hard (SH), that has long-lasting, very firm flesh and the non melting (NM), that produces a rubbery texture that is distinct from melting. Fruits from twenty four cultivars or selections with the above flesh types were assessed for ethylene prodn. rate, total, sol., and insol. pectins, and calcium content in the cell wall. SH fruits showed no or a very low ethylene prodn., always less than 10 mL/kg h, while the M and NM flesh produced more than 10 mL/kg h and the latter often more than 25 mL/kg h. Ethylene level seemed a useful index also because of its rather simple and fast measurement. Calcium and pectin content was also different, particularly the ion bound to the insol. pectin fraction. SH showed a high pectin content with a low sol./insol. pectin ratio, while the NM had the highest total pectin and high calcium content in the cell walls. MVF presented a low pectin content but with a low sol./insol. pectin ratio and the highest amt. of total and insol. pectin-bound calcium. [on SciFinder (R)]