Structural and functional properties of sodium caseinate glycosylated by dextran aldehyde

Glycosylation is an effective method of protein modification which can improve the functional properties of proteins. Traditional protein glycosylation methods are typically limited by slow reaction rates. A method for improving the efficiency of protein glycosylation from different degrees of dextran oxidation with periodate, to obtain dextran aldehydes, is presented. Increased molar ratio between periodate and glucose unit in dextran led to dextran aldehyde with higher aldehyde group content and reduced molecular weight. This is due to an increased oxidation, which increases the degree of glycosylation by 43.22%. Compared with dextran glycosylated products, the emulsifying activity, stability indices and foaming capacity of dextran aldehyde glycosylated products increased by 30.8, 301 and 50%, respectively, with poor foam stability. Dextran aldehyde-modified sodium caseinate presented lower digestibility and could maintain better stability against salt ions and heat treatment. The polysaccharide aldehyde showed great potential for expanding protein modification methods to promote its industrialization.