Supercritical fluid extraction of bioactive compounds from mango (Mangifera indica L.) by-products

Introduction: Mango (Mangifera indica L.) is one of the most important tropical and subtropical fruit crops in the world. The main mango varieties grown in Spain are Osteen, Keitt and Kent. Supercritical fluid extraction (SFE) has evolved as a green alternative to conventional methods for the extraction of bioactive compounds. Some advantages of this technology are the possibility of controlling the selectivity, of improving mass, high diffusivities and variable solvent strength, very useful to achieve highly selective extractions.

Methods: Extractions were performed using an SFE module; an amount of dry mango peel was loaded into the extraction vessel while a CO₂ and ethanol as co-solvent were used. Stream flowed through the sample at different temperature, pressure and time were optimized. The conditions were selected based on the total phenolic content and mass yield. SFE final conditions were; 15g of lyophilized skin or pulp, CO₂ and 15%EtOH as cosolvent, extraction pressure of 30MPa, 50°C and 3h extraction time. Total phenolic compounds by Folin–Ciocalteu method, total carotenoid compounds and antioxidant capacity (DPPH and FRAP methods) were evaluated. Also, bioactive compounds were studied and identified by HPLC/MS.

Results obtained shown that yield extraction varied depending on fruit area, variety and ripeness degree. In the skin, Kent variety presented higher extraction yield than Keitt variety. Also, the higher ripening stage, the higher extraction yield was observed in Kent variety.

Regarding total phenol content, at low ripeness stage, was higher in the pulp than in the skin and when ripening stage increases, the skin becomes enriched in phenol and decreases in the pulp. Similar results were found in total carotenoid content.

Conclusion: The proposed SFE method allows to obtain solvent free extracts rich in polyphenols and carotenoids from mango by-products and also can be used to perform the fractionation into different groups of compounds.