Removal of flaxseed mucilage by chemical and enzymatic treatments

The amount of flaxseed mucilage extracted into aqueous solutions was determined by monitoring the content of total sugars and pentoses as well as viscosity values. Whole seeds of flax were soaked and then treated with selected enzymes in order to reduce the content of seed coat polysaccharides. Soaking of seeds in water or sodium bicarbonate solutions or treatment with commercially available carbohydrases (Celluclast® 1.5L, Pectinex™ Ultra SP and Viscozyme® L) reduced the amount of mucilage remaining in the seeds, as indicated by the low content of pentoses, total sugars and viscosity values of water extracts. Scanning electron micrographs of treated flaxseed coats revealed differences in the cellular structure of the outermost epidermal layer when compared with those of untreated seeds. Nitrogen solubility of defatted meals from low mucilage seeds prepared via sodium bicarbonate soaking (0.10 M, 12 h) and treatment with Viscozyme® L (22.5 mg protein per 100 g, 3 h) was improved. The protein recovery from low mucilage seeds increased since a better isolation of protein from flaxseed was possible due to reduced interference of mucilage.