Chemometric analyses of 'Golden Smoothee' apples treated with two preharvest calcium spray strategies in the growing season

Chemometric techniques were used to analyse the effects of two preharvest c alcium strategies applied to increase the calcium content and improve the q uality of Golden Smoothee apples after prolonged storage in controlled atmo sphere, ultralow-oxygen (CA-ULO; 1% O-2, 2% CO2) conditions. In a two-year study the strategies applied by sprays were started 10 and 60 days after fu ll bloom (DAFB) with 10 and six calcium sprays respectively at 15 day inter vals throughout the growing season. The most effective results for increasi ng the calcium content of the apples were attained when the calcium was app lied fi om 60 DAFB with six sprays. Although the chamber effect and mainly the length of storage differentiate the fruits much more than the calcium s pray strategies, the evaluation of the results suggests that calcium and fi rmness remain correlated for up to 4 months of cold storage under CA-ULO co nditions. The effect of calcium decreases with storage time, Titratable aci dity and bitter pit incidence correlated negatively with calcium content in year 2, Comparison of the results obtained in the two years indicates that the relationship between calcium and the quality attributes depends not on ly on the calcium content per se, but also on other factors such as the nut ritional status. (C) 2001 Society of Chemical Industry.