Impact of 1-Methylcyclopropene and Controlled Atmosphere Storage on Pear Fruit Quality: Biochemical and Physiological Analyses

European pears are stored under controlled atmosphere (CA) and/or treated with 1-methylcyclopropene (1-MCP) to limit ripening and senescence. However, these practices can induce storage-related disorders in pears. A canonical powered-partial least squares analysis determined that senescent scald and internal breakdown in stored ‘AC Harrow Crisp’ pears were associated with decreased concentrations of ascorbate and accumulation of oxalate and gamma-aminobutyrate. These disorders and 1-MCP exacerbation of internal cavities were negatively correlated with total and reduced glutathione, reduced glutathione/oxidized glutathione and succinate. Internal cavities were associated with lactate accumulation, and negatively linked to malate depletion. Incidences of all three disorders increased with shelf-life in ‘Cold Snap’ pears following CA storage. Senescence-related disorders were reduced by 1-MCP and 2.5 kPa O2, whereas their impact on internal cavities was inconsistent across two years. Occurrence of these disorders was associated with high ethylene production rates, peel yellowing and fruit softening.