Studies on CA storage of fruits and vegetables

Part I. Effect of CA storage on the inhibition of sprouting and browning of chestnuts

Abstract

Conditions described here were air (room temperature), air (0°C), 9%CO₂-3%O₂ (0°C), 6%CO₂-3%O₂ (0°C), and 3%CO₂-3%O₂ (0°C). Relative humidity of CA-chambers was 85-90% and a CAchamber with lower humidity was also equipped.
There was no difference between the moisture losses (4-8%) of the nuts in air (at 0°C) and in CA condition after the storage period of 200 days, while the loss of moisture of the nuts in air (at room temperature) was 40%. Sprouting and rooting of the nuts was completely inhibited during the storage at 0°C. The nuts (cotyledon) stored for 3 months in air at 0°C began to brown when they were boiled for processing. The higher levels of CO₂ concentration (9% and 6%) delayed the ocurrence of the browning to 7 month after the nuts were stored.
Polyphenol content of the nuts increased gradually during the storage at 0°C and the increasing rate was depressed with higher concentration of CO₂ in the storage atmosphere. Immediately after being removed from cold storage room to a warm, especially from the CA-storage of 6%CO₂-3%O₂, polyphenol content in nuts increased sharply. Mold development was first observed at 6 months after stored at 0°C and 10% of the nuts were infected with mold after 10 month storage. The low humidity (70%) in a chamber reduced the development of mold growth.
From above observation, it was suggested that the optimum condition of CA-storage (at 0°C) for chestnuts was 6%CO₂-3%O₂ of atmosphere and 85-90% of relative humidity and that the storage life of chestnuts in CA storage was 8 months for the use of processing and 10 months for fresh fruits.