Use of Combined UV-C and Heat Treatments to Improve Postharvest Life of Strawberry

J PAN; AR VICENTE; GA MARTINEZ; PM CIVELLO; AR CHAVES

Toronto, Ontario, Canada

Congreso; XXVI International Horticultural Congress; 2002

International Society for Horticultural Science

Strawberry being a rapid decaying fruit, much of the research in postharvest science is devoted to the development of methods to improve its postharvest shelf life. Physical treatments involving a low UV-C dose (0.4600 J.cm-2) and heat treatment (45°C, 3 h in air oven) have been assayed both separately and in a combined way on strawberries (Fragaria x ananassa cv. Seascape) 70-80% surface red. After treatments, fruits were kept at 20°C for 2 days and fruit quality parameters such as surface color and lightness, anthocyanin content, total phenol and sugar content were measured. Also, development of surface fungal infections and a parallel ‘in vitro’ germination assay on conidia of Botrytis cinerea and Rhizopus stolonifer, were carried on to quantify treatments´ effect. For both the heat and combined treatments, development of surface hue was delayed, a result in accordance to the observed reduction in the anthocyanin content; for these same treatments, lightness loss was also delayed. Fruit treated with the combined physical treatments showed a steady phenol content along the running time in comparison to the decrement found in those on which the treatments were assayed separately. No significant differences among treatments were observed in the total sugar content, while an increased content of reducer sugars was recorded for the combined treatment. Over the experimental time (7 d after harvest), combined physical treatment reduced drastically surface fungal infections and delayed markedly ´in vitro´ germination rates (over 10h). As drawn from the results, a potential synergistic effect from the combination of both treatments can be foreseen for most parameters studied, thus suggesting an innovative physical method to improve postharvest life (i.e. prolong shelf life and maintain quality parameters), which might prove to be cheap, simple and market-appealing as well.