Development of an Enriched Polyphenol (Natural Antioxidant) Extract from Orange Juice (Citrus sinensis) by Adsorption on Macroporous Resins

Orange (Citrus sinensis) juice contains a high amount of antioxidant compounds, such as polyphenols and vitamins. The aim of this work was to develop an adsorption procedure for the quantitative recovery of polyphenols from fresh orange juice. Different macroporous resins have been selected to evaluate their affinity for phenolic compound in order to purify the antioxidant compounds from the orange juice. The main compounds of orange juice were firstly characterized using an UPLC-UV-HRMS to define the metabolite profile, and subsequently three different types of adsorbent (XAD-2, XAD-4, and XAD-16N) were tested to concentrate these bioactive compounds. The time of contact was selected based on kinetic studies, and subsequently the adsorption and elution conditions were optimized in order to maximize the recovery of phenolic compounds to obtain an extract rich of bioactive compounds. Lastly, antioxidant capacity of the orange juice extract of selected macroporous resin, obtained under optimized conditions, was determined by in vitro antioxidant assays.

Characterisation of nutraceutical compounds from different parts of particular species of Citrus sinensis 'Ovale Calabrese' by UHPLC-UV-ESI-HRMS

Consumers are aware of diet causing health problems and therefore there is an increased demand for natural ingredients that are expected to be safe and health-promoting. Many of these compounds belong to the class of flavonoids and can be divided into these five groups: flavanones, flavones, flavonols, flavanols, isoflavones and anthocyanidins. Extracts from citrus fruits are usually used as functional ingredients for several products. The aim of this paper was to develop an UHPLC-UV-ESI-HRMS method to define the metabolite profile of different parts of citrus fruit, of a particular cultivar called 'Ovale Calabrese', and in its main by-products. The high resolution mass spectrometry analysis allowed the identification of 27 compounds belonging to the classes of flavonoids and terpenoids. The high contents of phytochemical compounds, reveal the potential use of the 'Ovale Calabrese' as a rich source of nutraceutical compounds.