The Effect of Extraction Method on Physicochemical Properties of Mucilage Extracted from Yellow and Brown Flaxseeds

Background: Mucilage is an important polysaccharide with a broad range of physicochemical properties and antioxidant activity that is widely used for various applications in the medicine and food industries. Objectives: This study aims to evaluate the effect of the extraction method on the physicochemical properties of mucilage extracted from yellow and brown flaxseeds. Methods: Mucilage was extracted by different methods: heating, sonotrode, and bath sonication. The extracted mucilage was evaluated for mucilage extraction efficiency (MEE%), solubility, water-binding capacity (WBC%), antioxidant activity, and foam stability. Results: In all extraction methods, the MEE% of yellow flaxseed was significantly higher than that of brown flaxseed. The antioxidant activity of mucilage extracted from brown and yellow flaxseed was 43.65 ± 1.86% and 12.65 ± 1.23%, respectively (P < 0.001). In all extraction methods, the solubility of mucilage was increased by enhancing the temperature. Significantly, higher solubility (P < 0.01) and stronger foam stability (P < 0.001) was obtained for mucilage extracted from brown flaxseed. The highest foam stability was obtained by the sonotrode method. Mucilage extracted by sonotrode and bath sonication methods showed significantly stronger (P < 0.01) water-binding capacity (WBC%) compared to that of the heating method. Conclusions: Our results showed that the ultrasonic methods, especially sonotrode, due to their positive effects on physicochemical properties of mucilage, could be more appropriate methods for extraction of mucilage.