Instrumental and sensory quality characteristics of 'Gala' apples in response to prestorage heat, controlled atmosphere, and air storage

Fruit quality, sensory characteristics, and volatiles produced by 'Gala' apples (Malus xdomestica Borkh.) were characterized following regular atmosphere (RA) storage without and with a prestorage heat treatment (38 degreesC for 4 days) or controlled atmosphere (CA) storage at 0 and 2 degreesC for 0 to 6 months plus 7-day shelf life at 20 degreesC. Static CA conditions were 0.7 kPa O-2 Plus 1.0 kPa CO2, 1.0 kPa O-2 plus 1.0 kPa CO2, and 1.5 kPa O-2 plus 2.5 kPa CO2. Most of the more abundant volatiles were esters; the rest were alcohols, an aldehyde, a ketone, and an aryl ether. Respiration and ethylene production rates, internal atmospheres of CO2 and ethylene, and volatile levels were reduced following CA storage compared with RA storage without and with a prestorage heat treatment. Magness-Taylor and compression firmness, titratable acidity, and sensory scores for firmness, sourness, apple-fruity flavor, and overall acceptability were higher for CA- than for RA-stored fruit. Soluble solids content and sensory scores for sweetness were similar among all treatments. Quality and sensory characteristics were generally similar in heated and nonheated RA-stored fruit, and between 0 and 2 degreesC in CA-and RA-stored fruit. While one CA regime had a higher CO2 concentration than the others tested, CA effects on quality and sensory characteristics were generally more pronounced at the lower 02 levels. Quality characteristics declined between 2 and 4 months storage. The results indicate that short-term CA storage can maintain instrumental and sensory quality of 'Gala' apples.