Nutritional and nutraceutical quality of Vaccinium myrtillus and Vaccinium corymbosum fruits treated with UV-B radiation

Blueberries and bilberries, thanks to their high content of polyphenols and vitamins, are considered important sources of antioxidant compounds with strong health-promoting properties. However, among the different species belonging to the genus Vaccinium, a great morphological and biochemical variability can be found. Currently, in parallel with the development of genetic engineering, new eco-friendly technologies able to improve the nutraceutical quality of fruit and vegetables are emerging. Among these, the application of ultraviolet (UV)-B radiation of fresh plant-based food is very promising thanks to its ability to modulate many pathways involved in the biosynthesis of numerous beneficial secondary metabolites. The aim of the current research was to: 1) highlight differences in fruit quality between bilberry (Vaccinium myrtillus), that grows spontaneously in high mountain, and the most cultivated species, i.e., the blueberry Vaccinium corymbosum; 2) evaluate the effectiveness of post-harvest UV-B treatments in increasing the content of the main antioxidant compounds of the two species. Two experimental conditions were evaluated: 1) 12-h UV-B treatment (129.6 kJ m(-2)) followed by a 12-h recovery; 2) 18-h UV-B treatment (194.4 kJ m(-2)) followed by a 24-h recovery. V. myrtillus showed significantly lower dimensions and weight than V. corymbosum and, considering the color parameters (according to CIELAB system), it showed lower L* and higher a* and b* values. Besides, bilberries had a much higher content of total phenols, flavonoids and anthocyanins than cultivated blueberries, with a consequently higher antioxidant capacity. Following the UV-B treatments, no changes in weight or dimensions were detected. The exocarp color of V. myrtillus was unaffected by the treatment,