Effect of 1 and 100 kPa O-2 atmospheric pretreatments of whole 'Spartan' apples on subsequent quality and shelf life of slices stored in modified atmosphere packages

Whole 'Spartan' apples were exposed to 1 kPa O-2, air (21 kPa O-2) and 100 kPa O-2 at 1 degrees C for 5, 12 and 19 days. Subsequent to the pretreatmen t, apples were cored, sliced and 400 +/- 5 g of slices were sealed in 40-mu m-thick low density polyethylene film bags having a moderate O-2 transmiss ion rate (OTR similar to 2.28 fmol s(-1) m m(-2) Pa-1 at 23 degrees C) and held for up to 2 weeks at 1 degrees C. Cut surface browning and flesh softe ning were inhibited for packaged slices by pretreating the whole fruit with 100 and 1 kPa O-2 as compared with those from the air pretreatment. Howeve r the slices from the 100 kPa O-2- and air-pretreated apples contained a mu ch lower content of fermentation products associated with off-flavors compa red with the slices from apples pretreated in 1 kPa O-2. Packages containin g apple slices from the air pretreatment developed a more highly modified a tmosphere than packages containing apples slices from the other two pretrea tments, suggesting that both 1 and 100 kPa O-2 pretreatments suppressed the respiration rate of apple slices. Slices from apples pretreated with 1 kPa O-2 developed more cut surface browning and greater tissue solute leakage and enhanced accumulations of acetaldehyde, ethanol and ethyl acetate in ap ple slice tissue as compared with slices cut from the 100 kPa O-2-pretreate d apples. (C) 2000 Elsevier Science B.V. All rights reserved.