Superficial scald incidence in ‘Abate Fetel’ pears in relation to maturity, ethylene production and antioxidant capacity

Superficial scald (SS) is a storage disorder that affects 'Abate Fetel' pears stored for a long period resulting in important economic losses. Maturity at harvest, together with storage conditions, strongly affect SS: late harvest, controlled atmosphere storage, and 1-MCP treatment can prevent SS development. SS can be considered a chilling injury linked to oxidative processes occurring during storage, and its susceptibility depends on the interaction between ethylene production, a-farnesene and conjugated trienols accumulation, antioxidant content (phenols, ascorbate) and antioxidant capacity. The aim of this work was to study the relationships between maturity at harvest, non-destructively measured by time resolved reflectance spectroscopy (TRS), and SS incidence in relation to ethylene production and antioxidant potential in 'Abate Fetel' pears. At harvest, 780 pears were measured by TRS for absorption coefficient at 670 nm (μa670), ranked by μa670 in three maturity classes (less-LeM, medium-MeM and more-MoM mature), and randomized in different samples according to 1-MCP treatment (treated, untreated), storage time (17, 21, 25 weeks) and atmosphere (-1°C; air-NA; CA: 8-12 kPa O2, 1 kPa CO2). Fruits were examined after 7 days of shelf life for SS incidence and severity. LeM and MoM pears were also analysed for ethylene production (EP), total phenol content (TPC) and antioxidant capacity (TAC). SS increased with storage time reaching the highest values in untreated pears stored for 21 weeks. Maturity class significantly affected SS incidence as well as EP, TPC and TAC in combination with storage conditions and 1-MCP treatment. LeM untreated pears stored in NA showed the highest SS incidence and severity, coupled with the highest EP and low TPC and TAC. MoM 1-MCP-treated pears stored in NA and in CA showed the lowest SS incidence and the highest TPC and TAC while no difference was found for EP in treated LeM and MoM pears.