Enzymatic treatment enhances the efficiency of protein extraction from annual and perennial (L. usitatissimum and perenne) flax varieties

Flax protein has the potential to be a viable plant protein option that is nutritious. However, the presence of mucilage and the low solubility of flax protein pose challenges in protein isolation resulting in insufficient protein purity and yield. Enzymatic treatment may aid in enhancing the protein extraction process and the functionality of the resulting protein.

The aim of this research is to develop an efficient protein extraction protocol to obtain a functional flax protein isolate (FPI) from annual and perennial flax varieties.

Flax seed, from both annual and perennial varieties, were pressed, ground, and defatted to produce defatted flax meal (DFM). DFM was dispersed in water to remove excess gums. The pellet was redispersed in water, heated to 50°C, adjusted to pH 7.0, enzyme added, and the mixture was incubated for 30 minutes. Protein extraction trials were then performed following alkaline extraction at pH 8.0 and 9.0. A control extraction was performed without enzyme treatment. Extraction purity and yield of the resulting flax protein isolate (FPI) were evaluated.

Control protein extractions done at pH 8.0 and 9.0 resulted in 84.8% and 91.3% purity and 29.5% and 49% yield, respectively. With the enzymatic treatment, protein purity at pH 8.0 and 9 was 79.2% and protein yield was 84.6% and 44.2% and 51.3%, respectively. The protein purity of annual and perennial FPI were 71.8 and 85.9% respectively, while the experimental perennial flax line had a protein purity of 76.4%.

Results confirmed the success of enzyme-assisted extractions to produce FPI with enhanced yield and good purity. Successful production of FPI highlights the potential of both annual and perennial flax sustainable sources of novel plant protein. Domestication of perennial flax varieties and securing high-value end use applications have the potential to fulfill the demand for alternative and sustainable plant protein sources.