Effect of 100% CO2 treatment for keeping quality of strawberry fruits

'Hokowase' strawberries (Fragaria ananassa DuCH) were treated with 100% CO2 at 25°C for 0, 3, 6, 12, 18 or 24 hr. The flesh firmness of fruit increased for all CO2 treatments tested. The 6 hours treatment was the most suitable duration for maintaining quality of the fruit, because a long time treatment caused severe browning of sepal and an off-flavor of the fruit. The fruit which was stored 0, 24 or 48 hr. after harvest were treated with 100% CO2 for 6 hr. The delayed treatment, 24 hr. and 48 hr. after harvest, was more effective for increasing firmness and prevention of decay than non-treatment. The fruit were treated with 100% CO2 or N2 for 24 hr. CO2 treatment resulted in firmer fruit and a decrease of the ratio of water soluble pectin content and an increase of hexametaphosphate soluble pectin, while N2 treatment did not affect texture or pectin substances.