Relationship among dry matter content and maturity indexes at harvest and quality of ‘Gala’ apples after storage

Abstract

The objective of this study was to determine the relationship among dry matter content (DMC) and maturity indexes at harvest and quality of ‘Gala’ apples after storage. Apple fruit of four ‘Gala’ strains produced on two rootstocks and three growing regions were used for experiments 1 and 2. For all experiments, fruit harvest maturity was assessed one day after harvest and stored fruit was assessed after removal from storage plus seven days at 22 °C. For experiment 1, fruit were harvested weekly along the final stages of growth and maturation on the tree. For experiment 2, fruit were harvested at commercial maturity and stored under a controlled atmosphere at 0.7 oC for 195 days. For experiment 3, fruit from two orchards were harvested at commercial maturity and stored in air at 1oC for 50, 110, or 194 days. DMC did not change during the final stages of fruit growth, however, there were significant changes in fruit firmness, starch index, and soluble solids content (SSC) during the same period. At the commercial harvest, fruit DMC showed high correlation with SSC, titratable acidity (TA) and firmness. DMC assessed at the commercial harvest also showed high correlation after storage with SSC and TA but not with firmness or flesh browning (FB). DMC decreased slightly during storage. The results show that DMC is not a reliable index to determine ‘Gala’ apple maturity at harvest, or to predict fruit firmness and FB after storage. However, DMC at harvest has potential to predict SSC and TA after storage, two important fruit quality traits. Fruit density at harvest showed utility to predict risk of flesh browning after storage.