Squid discards as a source of phospholipid- and tocopherol-concentrates by employment of non-halogenated solvents

Abstract

This study focused on the preparation of phospholipid- and tocopherol-enriched concentrates from Patagonian squid (Doryteuthis gahi) discards. For it, non-halogenated solvents (hexane, HX; isopropanol, IP; ethanol, ET) were combined in one-step and two-step extracting systems and applied to this marine substrate. Total lipid, phospholipid (PL) and tocopherol values were determined and compared to those obtained by the conventional (chloroform/methanol) procedure. For one- and two-step strategies tested, non-halogenated solvents led to total lipid yields of ca. 65–79% compared to the conventional procedure; the two highest yields (p < 0.05) were obtained by the use of one-step HX/ET (2:1) and two-step HX/ET extractions. Regarding PL compounds, non-halogenated strategies led to a ca. 66–88% recovery compared to the conventional procedure. Notably, alcohol-containing solvent mixtures provided lipid fractions including higher average PL concentrations than the conventional procedure; thus, two-step HX/IP and HX/ET extractions led to significantly higher (p < 0.05) concentration values. In all lipid extracts, α-, γ- and δ-tocopherol compounds were detected, the first one being the most abundant. Two-step HX/IP and HX/ET extractions led to higher yields of α- and γ-tocopherol when compared to the conventional procedure. Remarkably, HX-containing mixtures provided lipid extracts including higher (p < 0.05) concentrations of α- and γ-tocopherol than the conventional procedure; concentration values were especially high if employing HX alone. Extractability differences are discussed and explained on the basis of the polar and non-polar characteristics of the solvents.