Chitosan/tripolyphosphate nanoaggregates enhance the antibrowning effect of ascorbic acid on mushroom slices

Enzymatic browning is the main deleterious phenomenon affecting the quality of minimally processed mushrooms. Nano-encapsulation of antibrowning agents provides a new strategy to prevent discoloration in minimally processed commodities. In this study, coatings containing AA-loaded chitosan/tripolyphosphate nanoaggregates were applied to evaluate the postharvest preservation of minimally processed mushrooms during 16 d of storage at 5 °C. Package headspace composition, browning index, firmness, phenolic and ascorbic content, antioxidant capacity and polyphenol oxidase activity were evaluated as quality indicators. The results indicate that nanostructured coatings can effectively alleviate browning development (browning index was significantly reduced) and maintain firmness. Higher levels of phenolic compounds, ascorbic acid, as well as improvement in antioxidant capacity were achieved with the application of nano-encapsulated ascorbic acid. Polyphenol oxidase activity was partially inhibited as a consequence of the high AA concentration maintained during storage. The results allow concluding that AA-loaded chitosan/tripolyphosphate nanoaggregates are an interesting alternative to prevent browning of fresh-cut mushrooms and maintain high ascorbic acid concentrations through refrigerated storage.