Formation and characterization of ovalbumin cold-set gel in simple food system

Abstract

The objectives of this study were to form soluble aggregates in simple food systems containing sucrose and NaCl and to investigate the influence of the soluble aggregates on gelation patterns of cold-set gels in simple food systems. Ovalbumin aqueous solution (2%, pH 7.0) was heated at 80 ?C. After cooling, gelation was induced by 0.1% glucono-?-lactone at 20 ?C. The weight average molar mass (Mw) of aggregates and the root mean square radius of gyration (Rg) of aggregates were determined by multi-angle laser light scattering detector. Formation of cold-set gels was monitored by development of the complex modulus (G*) at 20 ?C for 10 hr. With increasing the preheating time (1, 6 and 24 hr), native ovalbumin converted gradually to denatured soluble aggregates. After 24 hr, aggregates with high molecular weight were formed 87% of entire soluble aggregates. Mw of the aggregates increased slightly and Rg of the aggregates rarely increased with increasing sucrose concentration (0.1, 0.5 and 1 M). Mw and Rg of the aggregates increased rapidly with increasing NaCl concentration (1 and 2 mM), and Mw and Rg with two different cosolvents increased more than with sucrose or NaCl. Mw of the aggregates with 500 mM sucrose and 1 mM NaCl were the highest in all cases. Mw and Rg of the aggregates increased because of viscosity due to 1 M (34%) sucrose. So, these two cosolvents, sucrose and NaCl, can be important in controlling the properties of the cold-set gels.