Comparative structural and techno-functional elucidation of full-fat and defatted flaxseed extracts: implication of atmospheric pressure plasma jet.

Abstract

BACKGROUND\nThe relatively inferior techno-functionality, especially for the emulsifying and antioxidant activities of flaxseed protein/polysaccharides complexes partially limited its implication in health food system. The current study aimed to conduct the effects of atmospheric pressure plasma jet (APPJ) on the physicochemical, structural and selected techno-functional properties of flaxseed extracts.\n\n\nRESULTS\nThe results showed that the full-fat and defatted flaxseed extract solutions (5 mg/mL) displayed sustainable decline in pH values (-54.06%, -48.80%, P<0.05) and zeta potential (-29.42%, -44.28%, P<0.05), but gradual increase in particle sizes visualised by optical microscope during 0~120 s of APPJ treatment. Moreover, APPJ led to initial decrease but subsequent increase in protein carbonyls and secondary lipid oxidation products, and concurrently changed the spatial conformation and microstructure of flaxseed extracts as evidenced by endogenous fluorescence property and scanning electron microscope (SEM) imaging. Additionally, the protein subunit remodeling and gum polysaccharides depolymerization were differently initiated for full-fat and defatted flaxseed extracts after 30 s of APPJ exposure. Importantly, the emulsifying and antioxidant activities of defatted flaxseed extract were particularly improved as assessed by cyro-SEM observation and DPPH radical scavenging activity following 15~30 s of APPJ treatment, owing to the changing interactions between protein and gum polysaccharides, as well as the release of specific phenolic compounds.\n\n\nCONCLUSION\nAPPJ could serve as a promising strategy to tailor the specific techno-functionality of flaxseed extracts based on the mild structural modification. This article is protected by copyright. All rights reserved.