Laline Broetto

Heat shock and salicylic acid on postharvest preservation of organic strawberries

Heat shock and salicylic acid have been studied on shelf-life extension of fruits. The benefits of these techniques have been related to their effect on inducing physiological defense responses against the oxidative stress and pathogen development. The objective of this study was to evaluate the effect of heat shock and salicylic acid on the postharvest preservation and contents of total phenolics, anthocyanins, ascorbic acid, fresh weight loss and microbiological quality of organic strawberries cv. Dover. Strawberries produced organically and stored at 5 °C were subjected to heat shock (45 °C ± 3 °C for 3 h), application of salicylic acid (soaking in 2.0 mmol L -1 solution), heat shock in combination with salicylic acid and control. After treatment, the fruits were packed and stored in a climatic chamber at 5 oC ± 2 oC. At 1, 7 and 14 days, the experimental units were removed from refrigeration and kept at room temperature of approximately 20 oC for two days. There was no effect of treatments on fresh weight loss, incidence of pathogens or chemical variations in strawberry fruits during the storage period. In natural conditions, organically grown strawberries remained in good condition for sale up to seven days of storage in all treatments.

Atividade antioxidante e enzimática em morangos (Fragaria vesca L.) tratados termicamente combinados com ácido salicílico

Postharvest strawberry treatments are needed to induce resistance and increase the shelf life without loss of quality. Therefore, this study aimed to evaluate the effect of postharvest heat treatment in combination with salicylic acid in the antioxidant activity, enzymatic and incidence of fungi in the strawberry during storage. The experimental design was completely randomized in a 4x4 factorial design with four replications. Strawberries grow Dover were subjected to the following treatments: heat treatment (45 ° C for 3 h in an oven), application of salicylic acid (immersion for five minutes in 2.0 mM aqueous solution), combination of heat treatment with salicylic acid and control (untreated). Were stored for 1, 7, 14 and 21 days under refrigeration at 5 ° C with 90-95% relative humidity. The enzymatic activity of peroxidase (POD) occurred in the initial period of 1 to 7 days of storage strawberries treatment heat and with salicylic acid. Regarding the combination of salicylic acid and heat treatment occurred enzymatic activity in the presence of fungi. For polyphenol oxidase (PPO) activity, heat treatment showed an oscillation of activity, while salicylic acid and the combination of and salicylic acid with treatment heat showed no significant differences, and showed constant activity of PFO. For the treatment with salicylic acid the strawberries showed only 5% fungal incidence. The antioxidant activity of strawberries treated with salicylic acid was high in all periods except at 21 days.