Variation of chemical constituents, antioxidant activity, and endogenous plant hormones throughout different ripening stages of highbush blueberry (Vaccinium corymbosum L.) cultivars produced in centre of Portugal

Highbush blueberry (Vaccinium corymbosum L) cultivars produced in Centre of Portugal were evaluated during three different ripening stages. The amount of phenolic compounds, organic acids, vitamin C, and sugars were determined by HPLC-DAD-UV/Vis. The content of total phenolics, total flavonoids, pigments, and endogenous hormones were determined by spectrophotometric methods. The antioxidant capacities were determined by DPPH, CUPRAC, and lipid peroxidation methods. In all cultivars, the glucose and the citric acid were the predominant sugar and organic acid, respectively, whilst the delphinidin-3-O-galactoside was the main anthocyanin identified. The average content of each attribute varied significantly (0.01 < p < .001) with ripening stage. It was observed an accumulation of anthocyanins and abscisic acid in the last stages of ripeness, whilst the content of total phenolics, flavonoids and pigments, and the hormones indole-3-acetic acid and gibberellic acid, were higher in the first stages, suggesting a shift in the evolution of compounds throughout the ripening process. Practical applications Blueberry is an important natural product that contains high level of anthocyanins and other important compounds including glucose, fructose, vitamin C, and citric acid. These compounds are recognized as being responsible for health-promoting properties. This article evaluates how ripening process affects the evolution of bioactive compounds accumulation and how this can be used to promote higher accumulations of such compounds enchanting their fruit nutritional and functional quality. Our findings may provide a useful guide for adequate fruit development towards a better fruit quality. Moreover, these findings may deliver additional phytochemical-related information to blueberry growers and consumers as fresh fruits harvested at different ripening stages.