379: Antioxidant Enhancement of Canola Meal Using Supercritical Fluid Extraction of Canola Pressed Cake

Introduction

SFE combined with expeller pressing represents a sustainable alternative to conventional oil extraction methods, offering solvent-free processing that preserves bioactive compounds. After expeller pressing of canola seeds, SFE was applied to produce oil-free canola meal suitable for plant-based food products. This study evaluates the impact of SFE on the antioxidant content of canola meal and oil extracted from CPC and compares the results with hexane extraction of CPC.

Methods

CPC was obtained by expeller pressing at 65±5°C after microwave pre-treatment of canola seeds at 90°C. Meal1 was prepared through hexane extraction of oil from CPC, while meal2 was obtained by extracting oil from CPC using SFE. SFE durations ranged from 165 to 330 minutes, producing meals with oil levels ranging from 0.1% to 50%. Phenolic compounds were extracted using ultrasound-assisted extraction (UAE) with 70% methanol (v/v), while oil-soluble phenolics were extracted using a hexane/70% methanol mixture. Phenolics were quantified via high-performance liquid chromatography-diode array detection (HPLC-DAD), and antioxidant activity was measured using DPPH radical scavenging, ferric reducing antioxidant power (FRAP), and metal ion-chelation (MIC) assays.

Results

SFE significantly enhanced sinapic acid content in meal2 (390 μg/g dry weight (DW)) compared to meal1 (360 μg/g DW) and CPC (330 μg/g DW). Canolol concentration in oil extracted from meal2 was highest at 160 minutes (98 μg/g DW) but decreased with longer extraction durations. The highest TPC (4.3 mg gallic acid equivalent (GAE)/g DW) was observed in meal2 processed for 240 minutes, surpassing meal1 (3.9 mg GAE/g DW). Meal2 exhibited superior antioxidant activity, with the highest DPPH and TPC values at 240 minutes and the greatest MIC and FRAP values at 160 minutes, relative to meal1 and CPC.

Significance

These findings demonstrate the efficacy of SFE in preserving the antioxidant properties of canola meal compared to hexane extraction and expeller pressing alone. This research supports the integration of expeller pressing and SFE as a sustainable, solvent-free processing technology for developing value-added canola products suitable for food, feed, pharmaceutical, and cosmetic applications.

Authors: Nazanin Vafaei*, Olamide S. Fadairo, Martin G. Scanlon