Analysis of the contents of Ugni molinae Turcz fruits across the ripening stages

Abstract

Recently, a growing interest in fruits having a high content of health-promoting compounds has become a trend among consumers around the world. Wild berries have received special attention based on the high levels of healthy compounds present in them. In this work, we elaborate on the qualities of the murta (Ugni molinae Turcz) fruit such as the colour, the volatile organic compounds (VOCs) present, its antioxidant capacity and the phenolic compound content (including those of flavonols and anthocyanins) with respect to the different ripening stages. Four stages were established based on the skin colour parameters, which were consistent with the changes in the weight and size of the murta fruits. In addition, the total phenolic and flavonols content showed a decrease during fruit ripening, in contrast with the total anthocyanins content that increased at the final stages of ripening. Additionally, the antioxidant capacity was evaluated via two approaches: ferric reducing antioxidant power and 1,1-diphenyl-2-picrylhydrazyl discolouration assay; higher levels of antioxidants at the final stages were consistently observed. Furthermore, the VOCs profile showed terpenoids to be the main compounds, with the highest relative abundances in fully ripe fruits. These results allow us to propose a classification of the different ripening stages of the murta fruits. This would enable us to have better knowledge of this interesting fruit, which possesses highly healthy nutraceutical compounds.