Microalgae are a precious source of polyunsaturated fatty acids (PUFA), however extraction is difficult due to the peculiar microalgae cell structure. Here we describe a new method based on the application of chitosan nanoaggregates as CO2 responsive emulsifier, used to promote the swelling of algae cell wall and the formation of a large oil - ethanol interphase area during the ethanolysis. Tests were carried out with Pseudokirchneriella subcapitata and Nannochloropsis sp. at different biomass/ethanol/chitosan ratios. CO2 was added to trigger demulsification to promote an easy recovery of the lipid fraction. The highest yields in PUFA were obtained with Nannochloropsis sp. (207.9 mg/g of oil) using 0.4% wt of chitosan and 1:10 biomass:ethanol ratio; 43.6 mg/g of linolenic acid were obtained from Pseudokirchneriella subcapitata. Overall, because the method employs ethanol, a generally recognized as safe (GRAS) solvent, and food grade additives, it is suited for the preparation of PUFA supplements.
Keywords: Chitosan; Eicosapentaenoic acid (EPA); Emulsion; Functional food; Lipid; Microalgae; Polyunsaturated fatty acids (PUFA); Supplements.
Copyright © 2020 Elsevier Ltd. All rights reserved.