Elif Yaver, Asuman Kan, Yüksel Kan
Flaxseed mucilage mainly consists of soluble fibers in the outermost layers of the seed. Because of its unique functional properties, such as water holding capacity, water absorption capacity, oil holding capacity and emulsion activity, it can be used as a natural gum in the food industry. Flaxseed mucilage can also exhibit certain health benefits, including anti-obesity, anti-diabetes, anti-cholesterol and antioxidant activities. In the current study, flaxseed mucilage was extracted from meal, which is a cold-pressed flaxseed oil by-product, by two different extraction methods: conventional extraction (3 h stirring at 50℃) and ultrasound-assisted extraction. The influences of ultrasound-assisted extraction at different durations (10, 20 and 30 min) on the yield, color, functional and thermal properties of flaxseed mucilage were compared with the conventional method. The maximum mucilage yield (17.46%) was obtained with ultrasound-assisted extraction for 30 min. Compared to the conventional method, ultrasound-assisted extraction elicited higher L* and whiteness index values in mucilage samples. Moreover, flaxseed mucilage extracted by ultrasound-assisted extraction for 30 min had greater water holding capacity, water absorption capacity and solubility than the other mucilage samples. Besides that, the water and oil absorption capacities of flaxseed mucilage extracted by ultrasound-assisted extraction for 30 min were comparable to xanthan gum, and its solubility was higher. Gelatinization enthalpy (ΔH) values of mucilage samples extracted by conventional and ultrasound-assisted extraction methods were similar (p>0.05). The findings elucidated that flaxseed mucilage extracted from flaxseed meal by ultrasound-assisted extraction (30 min) is a natural, non-toxic and sustainable option for commercial gums, with high yield and good functional properties.