Flaxseed Proteins (Linum usitassimum): Thermal, Functional and Spectroscopic Characterization

Flaxseeds are well known for their good quantity and quality of protein. In the present study, an attempt was made to extract and characterize the properties of flaxseed protein fractions. The extraction and isolation of the protein fractions were done on the basis of the solubility-albumins (water soluble) and globulins (salt soluble) followed by isoelectric precipitation, dialysis and lyophilization. The results revealed that the protein fractions differed significantly in terms of isolation and yield, molecular and other properties. The protein yield was ample for both fractions as albumin yield was 37.9% and 30.0% for the globulin fraction out of the total protein. The recovered fractions were subjected to gel electrophoresis, exposing protein bands within the range of 9–50 kDa and 10–53 kDa for albumin and globulin, respectively. Albumin were found more soluble in acidic pH and had more water holding capacity, whereas globulin showed more solubility towards alkalinity and had more fat absorption capacity. DSC revealed that the denaturation temperature for both the fractions varied from 94.37 °C for albumin and 80.07 °C for globulin. The FTIR spectrum reflected that both fractions have absorption bands in amide A, amide I and amide II regions. The studied functional properties of the flaxseed protein fractions are promising for its utilization for various food applications viz., as stabilizers, foaming agents, etc.