Effect of 1 and 100 kPa O2 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 pretreatment, 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 transmission 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 softening 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. However the slices from the 100 kPa O-2- and air-pretreated apples contained a much lower content of fermentation products associated with off-flavors compared with the slices from apples pretreated in 1 kPa O-2. Packages containing apple slices from the air pretreatment developed a more highly modified atmosphere than packages containing apples slices from the other two pretreatments, 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 apple slice tissue as compared with slices cut from the 100 kPa O-2-pretreated apples. (C) 2000 Elsevier Science B.V. All rights reserved.