Bioactive lipid-enriched concentrates from squid discards by one-step and two-step extractions with non-halogenated solvents

Abstract

This study focused on the preparation of lipid concentrates with high contents of bioactive molecules. Different one-step and two-step extractions with non-halogenated solvents (hexane, HX; isopropanol, IP) were carried out on Patagonian squid (Doryteuthis gahi) discards. As a first step, HX extractions (one, two or three times) were carried out. The resulting substrates were extracted with IP (two, three or four times). Analysis of lipid extracts included total lipid, phospholipid (PL) and tocopherol values, and fatty acid (FA) profile. HX extractions led to remarkable α- and γ-tocopherol values (ca. 1400 and 23 mg kg⁻¹ lipids, respectively); no effect (P > 0.05) of the number of HX extractions was observed. IP extracts provided high PL values (383–501 mg kg⁻¹ lipids); the highest average values were detected with four IP extractions after three HX extractions. Values obtained for tocopherols and PLs were higher (P < 0.05) than those obtained by employing the conventional (chloroform/methanol, 1:1) lipid extraction (ca. 496 and 11 mg kg⁻¹ lipids and 400 g kg⁻¹ lipids, respectively). Range values detected for eicosapentaenoic and docosahexaenoic acid values and the ω3/ω6 FA ratio were similar to those obtained by the conventional procedure. A valuable procedure is proposed for obtaining PL- and tocopherol-enriched concentrates from marine waste with non-halogenated solvents.