Influence of amino acids on thermal stability and heat-set gelation of bovine serum albumin

• Thermal denaturation and gelation of bovine serum albumin in amino acid solutions has been studied. • Parallels between net increase in denaturation temperature and gel strength were critically examined. • The results indicated that amino acid additives utilize a common mechanism in these structurally different systems. This study investigated the parallels in the influence of amino acid additives on thermal denaturation temperature (T d ) and heat-set gelation of bovine serum albumin (BSA). Complete denaturation of BSA occurred only when the gelation temperature (T G ) was 14 °C above T d . Under these conditions, the relative effects of various amino acid additives on elevation of T d and gel strength followed a particular order. Further, while zwitterionic amino acids increased both the strength of junction zones and participation of protein in the gel network, sucrose increased the gel strength primarily by strengthening the existing junction zone. The net increase in T d of BSA was linearly correlated with the net increase in gel strength (ΔGS), indicating that the underlying molecular mechanism in both cases might be same. The results suggest that the rheological properties of protein gels can be enhanced by using amino acids, instead of polyols and sugars, as additives.