GALA, BRAEBURN, AND FUJI APPLES - MATURITY INDEXES AND QUALITY AFTER STORAGE

Changes in apple maturity indices and fruit quality were measured week ly at harvest and after storage for 'Gala' 'Braeburn,' and 'Fuji' appl es. Fruits were evaluated on the day of harvest and after seven days a t room temperature for internal ethylene concentration (IEC) skin colo r, firmness, starch index (SI), total soluble solids concentration (SS C) pH, and titratable acidity (TA). Color, firmness, SSC, and TA were again measured after 6, 12, 18, and 24 weeks for 'Gala' and 8, 18, 24, and 32 weeks for 'Braeburn' and 'Fuji' held in cold storage at 0 +/- 0.5C. Optimum harvest dates were determined retrospectively using cons umer taste tests conducted approximately every four weeks for 'Gala' a nd every eight weeks for 'Braeburn' and 'Fuji.' Horticultural maturity of 'Gala' was attained 122 DAFB for long-term storage. On that date, St was highly variable, SSC was at 11 degrees Brix, and IEC averaged o ne ppm, but fruit color was not fully developed. I;ater-harvested frui t had the best eating quality after short-term storage in October and November. 'Braeburn' picked 168 and 175 DAFB had the best storage pote ntial. SSC was the most obvious maturity index in 1991. Fruit harveste d 154 DAFB was already capable of producing autocatalytic ethylene whe n ripened seven days at 20C. SI increased too late (175 DAFB) to be us ed as a predictor of harvest. Fruit harvested before 168 DAFB develope d scald and later harvested fruit had very low sensory ratings after 2 4 weeks in storage. IEC in 'Fuji' fruit stayed at low levels and witho ut autocatalytic production and therefore could not be used as a physi ological predictor of maturity. Obvious indices were the starch index and hue value of the ground color. The former increased suddenly and t he latter decreased by 173 DAFB. Only fruit picked 173 and 180 DAFB we re free from scald and retained good sensory quality after eight month s storage.