Abstract:

This study aimed to investigate the influence of varieties on the storability of green walnut (Juglans regia L.)
fruits. Green walnut fruits from three early-fruiting, mid-late ripening varieties, ‘Liao 2’, ‘Luguang’, and ‘Xifu 2’, were
stored at 0–1 ℃ and relative humidity (RH) of 85%–90%. Changes in physiological and biochemical properties of green
husk and kernel traits were measured to investigate the effectiveness of quality preservation. The results indicated that the
peak ethylene production rate appeared on 30 of storage for ‘Liao 2’ fruit, being 6 d earlier than for ‘Xifu 2’ and ‘Luguang’,
and the peak value was about 4 folds higher than those for the latter two varieties. Two respiration peaks of ‘Liao 2’ fruit
appeared on days 12 and 36, respectively, each being 6–12 days later than those of the other two varieties. Among three
varieties, ‘Liao 2’ decayed most slowly. at the end of 48-day storage, decay indexes (DIs) of ‘Liao 2’, ‘Luguang’, and ‘Xifu
2’ were 14.0%, 17.8%, and 21.1%, respectively. The activities of PPO and POD, and the content of phenols and flavonoids
in green husk of Liao 2 were continuously lower than those of the other two varieties. After 48-day storage, the changes in
soluble protein, acid value, peroxide value of walnut kernel of ‘Liao 2’ were minimal. It is concluded that low activity of
phenol oxidation in green husk of ‘Liao 2’ contributes to its better storage tolerance.

Key words: green walnut fruit, varieties, storability, oxidative enzyme, phenol