Cobertura comestível de quitosana adicionada de óleo essencial de Sálvia esclareia na conservação de morangos

Abstract

Strawberries currently have great importance for the world market, since they are destined for in natura consumption and processing of specific products, due to this it is associated application with coverings in order to increase the useful life of the fruits. Several studies have been carried out with chitosan based coatings and essential oils, which together can improve fruit conditions during a certain period of storage time. Initially the strawberries were selected and sanitized with chlorinated water solution (100 ppm), these were covered: acetic acid (AC); chitosan (Q); chitosan and sage essential oil clarifies (OHS) and without cover (C). Afterwards, they were packed in polystyrene trays, wrapped with polyvinyl chloride film (PVC) and stored in a refrigerator at 10ºC for 10 days. The fruits were evaluated every two days, regarding mass loss, pH variation, vitamin C content, color difference, and microbiological activities. Vitamin C content and pH variation did not present statistical differences between treatments. The percentage of mass loss was more significant in the treatment without edible cover, whereas the treatment Q behaved in a similar way when compared to the treatment without cover, this effect is described by the hydrophilic nature of chitosan that allows interaction with particles of water in the environment. The most stable treatment in relation to the others was the coverage of chitosan and sage essential oils. The vitamin C content varied during storage, presenting a total loss of 44% for treatment C, 43% treatment AC, 45% treatment Q and 25% treatment QOE. The QOE treatment provided a lower loss of vitamin C degradation, maintaining its physiological and nutritional characteristics. Microbiological activity increased in the last days between treatments. However, treatments C and AC showed presence of filamentous microorganisms in the last days of storage, leading to rot. The application of chitosan-based coating combined with sage essential oil clarified presented a viable alternative to maintain fruit quality during refrigerated storage by preserving the physico-chemical characteristics and greater stability in the microbiological characteristics.