Exploring the effect of roasting and ultrasound treatment on the emulsifying properties and oxidative stability of flaxseed gum-stabilized oil-in-water emulsions

Author(s)

El Mehdi Raoui, Milad Hadidi, Jose L. Toca-Herrera, Alexander Einschütz Lopez, Guruprakash Subbiahdoss, Herwig Peterlik, Marc Pignitter

Abstract

The current study investigated the effects of microwave roasting of flaxseed, combined with ultrasound-assisted emulsification as a dual-modality approach to enhance the techno-functionality of flaxseed gum as a natural emulsifier. The interfacial microstructure of flaxseed gum was characterised using atomic force microscopy (AFM) while the oil-water interface of flaxseed gum was examined by cryo-scanning electron microscopy (cryo-SEM). In addition, the internal structure of the emulsions was analysed using small-angle X-ray scattering (SAXS). The findings indicated that gum from roasted flaxseed had a notable impact on reducing the tension (6.42 mN/m) in the oil-water interface in comparison to lecithin (control) (17.44 mN/m). The emulsion stabilized by gum from roasted flaxseed using ultrasound-assisted emulsification (RS) led to a significant reduction in droplet size from 1.684 μm for emulsion stabilized by gum from non-roasted flaxseed without ultrasound-assisted emulsification (E) to 0.279 μm for RS and a high absolute surface charge value of 58.84 mV (p < 0.05) in comparison to E with an absolute value of 38.99 mV (p < 0.05). Emulsion stabilized by gum from non-roasted flaxseed using ultrasound-assisted emulsification (ES) and RS exhibited a heterogeneous microstructure with dense and clustered networks as shown from cryo-SEM. The physicochemical shelf-life test demonstrated that RS exhibited sedimentation stability and delayed lipid oxidation compared to other emulsions after one month of storage at +4°C. These findings suggest that ultrasound emulsification combined with microwave roasting of flaxseed prior to gum extraction can enhance the emulsifying properties and oxidative stability in oil-in-water emulsions for food applications.

Organisation(s)

Department of Physiological Chemistry, Faculty Center for Nano Structure Research

External organisation(s)

Vienna Doctoral School in Chemistry (DoSChem), University of Natural Resources and Life Sciences

Journal

Future Foods

Volume

12

ISSN

2666-8335

DOI

https://doi.org/10.1016/j.fufo.2025.100777

Publication date

12-2025

Peer reviewed

Yes

Austrian Fields of Science 2012

211202 Food technology, 104009 Food chemistry

Keywords

ASJC Scopus subject areas

Food Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/71c77afc-8ac4-4444-a1cf-4c649a93821f