Effects of various O₂ and CO₂ concentrations on the quality of “Okubao” peach fruit during storage

Peach fruits(Prunus persica L. Batsch. cv. Okubao)were stored in various gas composition(O₂: 1%, 5%, 10%, CO₂: 1%, 5%, 10%) at 0℃ for 60 d, and then sensory evaluated and measured firmness, browning intensity, soluble solids contents(SSC), pH value, membrane permeability and juice extraction rate immediately as well as after 3 days shelf-life at 20℃. Results show that 1% O₂ is harmful to peach fruit which surface colour changes unnormally, and off-flavor is lost. As compared with cold-stored fruits, peach fruits stored in (5～10)% O₂+(5～10)% CO₂, especially in 10%O₂+10%CO₂, remain preferable quality including flavor, texture and colour, slower softening speed as well as lower pH value and juice extraction rate after 60 days, which means chilling injury is reduced greatly, but the soluble solid content of the fruit has not been affected obviously. Under the same O₂ concentrations, the softening degree, brown-index decrease degree, pH value increase degree and membrane permeability increase degree increase with the increase of CO₂ concentration, which show that the fruit can ripe normally. The results show that the optimum gas composition is 10% O₂+10% CO₂ for “Okubao” peach in controlled area storage.