Postharvest chitosan treatment on blueberry (Vaccinium corymbosum) quality during long-term cold storage

Maintaining fruit quality is one of the main concerns during postharvest storage of produce and its forecasting could play an important role in orienting and organizing the storage strategies. Bioactive, antioxidant substances, such as polyphenols and ascorbic acid are important quality parameters for blueberry fruits. Blueberries ‘Brigitta’ were treated with chitosan, a GRAS (generally recognized as safe) compound effective as alternative to conventional fungicides for the control of postharvest diseases of fresh horticultural produce. Berries were cold stored (4°C) in natural air and total polyphenols, total flavonoids, total anthocyanins and non-anthocyanic flavonoids were determined after 0, 30, 60, 90, 120 and 150 days storage. At the same sampling times, ascorbic acid content and antioxidant activity were analyzed to evaluate the antioxidant status of the fruit. The research aimed at defining the impact and effectiveness of chitosan treatment in decreasing postharvest blueberry decay and detrimental effects on fruit quality. Results show a positive effect of postharvest application of chitosan, which can reduce fruit decay and deterioration (including fruit showing rots, shrivel, blemishes and mechanical damage), maintain fruit quality and extend storage life. Moreover, the qualitative analysis performed by PCA (principal component analysis) highlights the samples behavior during the cold storage period, suggesting the possibility to forecast fruit quality traits and storability.