# Valorization of canary seeds lipid fraction and defatted flour by supercritical carbon dioxide extraction

## TL;DR

This study shows that using supercritical CO2 to extract lipids from canary seeds produces high-quality oils and improves the properties of the remaining flour for food applications.

## Contribution

The study demonstrates the benefits of using supercritical CO2 over traditional methods for extracting lipids from canary seeds.

## Key findings

- SCCO2 extraction preserved tocopherols in the oil, with γ-tocopherol being the most abundant.
- Defatted flours from SCCO2 showed improved hydration, surfactant properties, and higher elastic modulus in gels.
- SCCO2-extracted flours had higher amylose retrogradation and could be promising food thickening agents.

## Abstract

Canary seeds (Phalaris canariensis L.) are rich in starch, proteins, and lipids, especially polyunsaturated fatty acids, however their potential remains underexplored.

This study evaluated supercritical CO2 extraction (SCCO2) to obtain valuable lipids and defatted flour, evaluating the chemical characterization of the extracted oils and a thorough assessment of the properties of the resulting defatted flours. Refined (RF) and whole (WF) flours were defatted by SCCO2 (41 ± 1 °C, 40 ± 1 MPa, 360–540 min) and compared with hexane extraction (HX) (80 °C).

The fatty acid profile of the lipid fraction of RF and WF revealed no significant differences, both being rich in mono- (14 g/100 g-oil) and polyunsaturated (76 g/100 g-oil) fatty acids. Unlike HX, SCCO2 preserved the tocopherol content in the extracted oil, with γ-tocopherol being the most abundant form. WF exhibited better hydration and surfactant properties than RF after defatting. Defatted flours showed increased peak (19–38%) and breakdown (20–45%) viscosities respect to the original flours due to lipids limiting water absorption. SCCO2-defatted flours showed the highest amylose retrogradation, with setback viscosity up to 26% higher than non-defatted samples. All flours studied showed the ability of forming gels with a predominantly elastic character. Gels made with SCCO2-extracted flours showed an increased elastic modulus (+20%) with respect to HX-extracted ones indicating an increased elastic behavior. In conclusion, SCCO2-extracted oil contained valuable polyunsaturated fatty acids and preserved tocopherols, whereas defatted flours improved functional and gelling properties, making them promising food thickening agents.