Succinylation of sodium caseinate and its effect on physicochemical and functional properties of protein

Succinylation is one of the most widely studied modification processes and well known to alter functionality of food proteins. Sodium caseinate (NaCas) is widely applicable protein ingredient among different varieties of caseinates. But hardly we find reports on effect of succinylation on physicochemical and functional properties of NaCas. Therefore, the present work was attempted to investigate the effect of succinylation on the functionality of NaCas. Ninhydrin method was adopted for the quantification of succinylation. Highest degree of succinylation was achieved at the level of 4 mol of succinic anhydride/mol of lysine in NaCas. Findings from surface hydrophobicity stated that NaCas undergoes structural modification upon succinylation. Further, the effects of succinylation on different functional properties of NaCas were evaluated. The solubility of NaCas improved significantly (P < 0.05) up on succinylation at higher pH values (>= 6). Other properties like water- and oil-binding capacity, viscosity and emulsifying properties of native NaCas increased significantly (P < 0.05) with no change in foam capacity and significant reduction in foam stability than native NaCas. Succinylation led to structural modification of protein and improved some functional properties of NaCas. The modified form of NaCas could be incorporated in food systems where fat management plays a critical role. (C) 2015 Elsevier Ltd. All rights reserved.