Effects of Water Loss of 'Fuyu' Persimmon Fruit on Mesocarp Cell Wall Composition and Fruit Softening

The effects of storage humidity on persimmon fruit deterioration and cell wall composition were investigated. Under a low humidity condition (20°C, 60% RH), fruits underwent a more rapid rate of water loss, ethylene production and fruit softening than did those stored under a high humidity condition (20°C, ≧ 98.5% RH). Arabinose (Ara) and galactose (Gal) in the pectic fraction of mesocarp cell walls decreased significantly under low than high humidity at the late stage of fruit softening as did the cellulose fraction. Fruit firmness is significantly correlated to contents of Ara and Gal of water-soluble (WS), pectic and hemicellulose and that of cellulose, which suggest that these components influence the integrity of mesocarp cell walls of persimmon fruit. Water loss and induced ethylene are involved in the decrease in contents of Ara and Gal in pectin and cellulose content, leading to fruit softening.