EXTENSION OF STRAWBERRY SHELF-LIFE BY IRRADIATED EDIBLE COATING

The aim of this work was to verify the influence of gamma irradiation on properties modification of a protein edible coating (calcium caseinate and whey protein isolated, added of potassium sorbate (PS) as an antimicrobial agent - film A) to enhance the shelf-life of fresh strawberries. The fruits were divided in four groups: (1) coated with film A without antimicrobial agent, (2) coated with film A, without irradiation (3) coated with film A, treated at 35.0 kGy and (4) uncoated fruits (control). The effects of gamma-irradiation on the structure of the edible coating were studied by SEM and rheology properties. In order to evaluate the fruits' shelf-life the following analysis were carried out: total counting of moulds and yeasts, color, weight loss, firmness and sensorial analyses. The results showed that PS was effective against Botrytis cinerea, increasing the shelf-life in 200% when compared with the control. The irradiation did not affect the antimicrobial agent. The irradiated coating improved significantly (p<0.05) some quality parameters (color, firmness, weight loss and sensorial attributes) in the last day of storage when compared with the non-irradiated. The induced modification on the protein coating solution by gamma-irradiation can be an efficient alternative to improve the shelf-life of fresh strawberry.