Effect of treatment on postharvest decay, Botrytis cinerea growth and ripening of strawberry fruit.

MARTINEZ, G.A; CIVELLO, P.M.; ROZENFELED, P.A.; SERRADELL, M.A.; CHAVES. A.R.; AÑÓN, M.C.

Madrid, España

Workshop; International Workshop of Phisiological and Technological Aspects of Gaseous and Thermal Treatments of Fresh Fruits and Vegetables; 1998

Strawberry fruits of comercial maturity were treated at temperatures ranging from 39°C up to 50°C during 1, 2, 3, 4 and 6 hours. Afterward, fruits were placed at 0 C overnight and then held at 20°C during 3 days. Fruit decay, color development and fungal growth were wvaluated during the incubation period. Treatments at 42°C, 45°C and 48°C during 3 h showed less level of decay and fungal development. Some of these treatments were chosen to analyse the growth of Botrytis cinerea and the evolution of ripening parameters. Friuts were inoculated with conidial suspension of Botrytis cinerea before and after the heat treatments and then incubatedat 20°C. It was observed thar fruits inoculated and tehn treated showed less fungal development than fruits treated and then inoculated or control frutis (inoculated and not treated). To analyse ripening parameters, fruits with lesser ripening stage (50-75% Red) were utilised. Heat treated strawberriesshowed lower softening rate, external color development, anthocyanin level and phenylalanine ammonia-lyase activity than control fruits. However, sugar content was the same in control and treated fruits. Heat treatment did not affect peroxidase activity and slightly increased the activity of poliphenoloxidase. Incorporation od S35-methionine into proteins was also evaluatedand it was observed that heat treatments caused a decrease in protein synthesis. These results suggest that heat treatments on strawberries can reduce fruit decay and fungal growth and delay ripening. Therefore, heat treatments could be a useful method to prolong the storage life of strawberries.