EFFECTS OF CONTROLLED ATMOSPHERE STORAGE ON STORAGE LIFE AND SHELF LIFE OF THE JAPANESE ONION CULTIVAR 'SUPER-KITAMOMIJI'

Abstract

'Super-Kitamomiji', a leading onion (Allium cepa. L) cultivar in Hokkaido, was stored under controlled atmosphere (CA) to investigate the effects of CA storage on storage life and shelf life and to assess the practicality of a CA storage facility. Bulbs were stored for 92 days, 135 days and 196 days in a regular air refrigerator (-0.5°C, 80% RH) and in a CA refrigerator (1°C, 80% RH, O 2 : 1%, CO 2 : 1%), and grading, sprout and root growth, firmness, total soluble solid content, pyruvate content and sugar content were investigated. The same items were also investigated in bulbs after storage at 15°C for 14 days in order to determine shelf life. Sprout growth and root growth were inhibited during CA storage. The ratio of unmarketable bulbs 14 days after CA storage was also lower than that after regular air storage. Total sugar content and pyruvate content increased during storage, but there was no significant difference between the contents in bulbs after regular air storage and CA storage. The results suggested that CA storage will enable the time limit for distribution of onions to be extended from April to June. Based on these results, CA facilities were constructed in Kitami (2,600 t, 2 rooms) and in Furano (6,700 t, 7 rooms), and bulbs have been stored in these facilities up until July.