Polyphenol content and antioxidant activity of maqui (Aristotelia chilensis Molina Stuntz) during fruit development and maturation in Central Chile
Maqui (Aristotelia chilensis Molina Stuntz, Elaeocarpaceae) is a Chilean native species which produces small berries that are mainly collected from the wild. The health benefits of maqui fruit are attributed to their high polyphenol content as well as their wide variety of anthocyanins and flavonols. One of the main factors that affect the polyphenol content in fruit is the maturity stage at harvest. The objective of this study was to determine total phenol and total anthocyanin content and antioxidant activity (by ferric reducing ability of plasma FRAP assay) of maqui fruits harvested at different fruit maturity stages from two wild populations located in Central Chile. Each maturity stage was determined by days from fruit set, berry size, and soluble solids. Total phenol content declined while total anthocyanin content increased from the green to light red stage. Nevertheless, both total phenol and anthocyanin content increased from the light red to dark purple stage. The highest anthocyanin content and antioxidant activity was found in the late maturity stage (dark purple). The results show that ripening in maqui fruit can be expected with 1100 growing degree-days (91 d after fruit set) in Central Chile. At this moment of harvest, fruits with 18-19 °Brix have the highest anthocyanin content and antioxidant activity (FRAP). This study constitutes the first advances in the understanding of maqui fruit ripening and corresponding antioxidant activity.