Differential effects of CO2 at low and high O2 on the storage quality of two apple cultivars.
Ben-Arie, R.; Levine, A.; Sonego, L.; Zutkhi, Y.;
Acta Horticulturae Year: 1993 Issue: No. 326 Pages: 165-174 Ref: 13 ref.
1993
บทคัดย่อ
The effects of a range of CO2 levels (0-20%) at low and high O2 levels (3% and 15%) were examined in Jonathan (JO) and Golden Delicious (GD) apples in storage. Fruits were stored at 0 deg C in 3-litre plastic barrels and examined 3 times at intervals of 2 months on removal from storage and after one week at 20 deg . Characteristics measured were external CO2 injury and incidence of superficial scald, internal CO2 injury, green-yellow colour, fruit firmness, SS content and titratable acidity of juice and ethylene production. JO was more sensitive than GD to CO2 injury, which appeared both externally and internally in the former and only externally on the latter. The threshold for peel injury to JO was 10% CO2 and it occurred more severely and earlier at 15% O2 than at 3% O2. GD peel injuries occurred at 15% CO2 + 3% O2, with little difference between the two O2 levels at 20% CO2. The development of superficial scald (which did not occur at 3% O2 on either cultivar) diminished at 15% O2 with increasing CO2 and was completely inhibited by 20% CO2. Fruit softening was inhibited with increasing CO2 levels in a similar manner at both O2 levels, even though the higher O2 level enhanced softening. No softening occurred at 20% CO2 regardless of O2 level both during storage and subsequent ripening. This could be related to the total inhibition of ethylene evolution which occurred at 20% CO2 at both O2 levels. Chlorophyll degradation was predominantly inhibited by increasing the level of CO2 for JO and by reducing the O2 level for GD. Titratable acidity, which is higher in JO than GD, was affected in JO only by reducing the O2 level. In GD, acidity was highest when CO2 was increased to 10% at 15% O2 and to 5% at 3% O2. These differences in organic acid metabolism in response to CO2 might be related to the different susceptibilities of the cultivars to CO2 injury.