Softening and cell wall metabolism in late-season peach in response to controlled atmosphere and 1-MCP treatment

Softening of peach (Prunus persica L. Batsch) fruit is generally rapid at ambient temperature, which limits considerably the commercial life of the produce. Modifications in the cell wall are believed to underlie changes in fruit firmness and texture. In this work, the effects of controlled atmosphere (CA) storage and 1-methylcyclopropene (1-MCP) on cell wall composition and on the activities of some cell wall-modifying enzymes were assessed in ‘Tardibelle’ fruit, a late-season, melting-flesh peach cultivar. CA storage and 1-MCP treatment applied separately were effective in delaying the softening of ‘Tardibelle’ peach during shelf-life at 20ºC following cold storage, apparently through different mechanisms. CA storage partially inhibited the activities of some pectolytic enzymes and increased the content of pectic polysaccharides, possibly related to delayed softening. 1-MCP treatment caused increased pectin methylesterase activity, but other pectolytic enzymes were inhibited, resulting in an enrichment of chelate-soluble pectin in the cell walls. In contrast, a combined treatment (i.e., CA plus 1-MCP) was unsatisfactory for retaining fruit firmness, apparently due to the extensive degradation of pectin.A. Ortiz was a recipient of an FPU grant from the Ministerio de Ciencia e Innovación (MICINN) of Spain. This work was supported by the Ministerio de Ciencia y Tecnología (MCyT), Spain (Project No. AGL2003-01457), and by Research Contract No. 2005SGR00630 funded by the Catalan Government. Partial financial support through the ISAFRUIT Project, funded by the EU under the 6th Framework Programme of RTD (Contract No. FP6-FOOD–CT2006-016279) is also gratefully acknowledged.Peer reviewe