果実に及ぼすガス濃度の影響 (第10報)

Abstract

To clarify the effects of CO2 levels (0, 3, 5, 10%) combined with low (3%) and high (19-21%) O2 levels in CA storage, and to compare the flesh brownings in the fruits stored at different stages of maturity, Jonathan apples were picked on both Sep. 30 (152 days after full-bloom) and Oct. 9 (161 days), 1972, and were stored at 4°C for two months.The higher the CO2 levels combined with high O2 level, the more slowly the ground color yellowed and the flesh softened. After one month, more acidity was found at 5% CO2 than at 0 and 10% CO2.At 3% O2 without CO2, yellowing of the ground color, softening of the flesh and decrease of the acidity were retarded in comparison with that in air.At 3% O2, the suppressive effect by CO2 was unclear on the yellowing, but was more marked on the softening. When combined with 5% CO2, the acidity decreased as in air, but with 3% CO2, the highest level of acidity and the best quality were obtained among the treatments.More flesh brownings were found in atmospheres with higher CO2 and low O2 level, and in more-matured fruits. In the matured fruits, many of the brownings were found near some vascular bundles, and in some cases, cavities developed in the browned tissues.The optimum CO2 level for CA storage seemed to be lower at the low O2 level than at the high O2 level. At 4°C, the optimum gas condition for CA storage of Jonathan seemed to be (CO2 3%+O2 3%). For CA storage, it seemed important to pick the fruits earlier than those for cold storage. Discussions were made about the optimum harvest date in relation to flesh brownings.