Ultrasonic-assisted virgin coconut oil based extraction for maximizing polyphenol recovery and bioactivities of mangosteen peels.

Virgin coconut oil (VCO) and propylene glycol (PG) have received more attention as bio-based solvents for natural bioactive recovery in green extraction process. Here, maceration extraction and ultrasound-assisted extraction (UAE) of bioactive phenolics from mangosteen peel (MP) by VCO, PG and VCO-PG mixture were compared. The goal was to maximize the phenolic extraction and improve bioactivities. Based on a single-factor experiment for UAE with VCO, the optimal condition was sample to solvent ratio of 1:6.6 g/mL, amplitude of 55 µm, and extraction time of 7 min, which yielded total phenolic content of 365 mg GAE/100 g. Regarding the extraction methods and bio-based solvents, UAE with mixed VCO-PG was not only provided greater polyphenol yield in a shorter time, but it also enhanced the bioactivities (radical scavenging, antibacterial, and antidiabetic activities) of the extract. Therefore, UAE can be potentially used in combination with bio-based solvents, especially mixed VCO-PG, for maximizing bioactive phenolic isolation from MP. This study provided an alternative method for production of bio-based oil solution from MP which can be directly used as a functional ingredient in emulsion based food, neutraceutical and cosmetic products.