1-MCP and storage conditions on the ripening and production of aromatic compounds in Conference and Alexander Lucas pears harvested at different maturity stages

The objective of this investigation was to evaluate the quality parameters and aroma profiles of Conference and Alexander Lucas pears after 7 months of storage. Fruits of both cultivars were harvested at two different maturity stages and stored under cold (CS) (20.9 kPa O2 + <0.04 kPa CO2), controlled atmosphere (CA) (2 kPa O2 + <0.7 kPa CO2) and ultra-low oxygen condition (ULO) (0.7 kPa O2 + <0.7 kPa CO2). CS and CA storage also included treatment with 1-methylcyclopropene (1-MCP) at 300 nL L−1. After seven months of storage at 0 ± 0.1 °C and 94 ± 2% RH plus seven days at 20 ± 2 °C and 60 ± 5% RH, fruits were evaluated for flesh firmness, peel color ('hue' angle = h°), soluble solids content (SSC), titratable acidity (TA), respiratory rate, ethylene production rate, and production of aromatic compounds. Fruits of both cultivars from the first maturity stage treated with 1-MCP did not develop a buttery texture or yellow color and produced significantly less alcohols and esters. A combination treatment (1-MCP + CA) most severely suppressed aroma development, particularly in the Conference cultivar. ULO storage also reduced yellowing, ethylene production and the development of aromatic compounds in both cultivars from the first maturity stage, but this reduction was less pronounced than that observed for 1-MCP treatments. The production of aromatic compounds was lower in fruits from ULO, regardless of their maturity stage. Fruits from the second harvest treated with 1-MCP had significantly more aromatic compounds than did those from the first harvest. In general, the CA condition has no effect on the ripening and production of aromatic compounds in both cultivars compared to CS.