THERMAL GELATION OF GLOBULAR-PROTEINS - INFLUENCE OF PROTEIN CONFORMATION ON GEL STRENGTH

Circular dichroic analysis of protein fluid expressed from globular protein gels at high centrifugal force has been used to elucidate the structural state of globular proteins in gels. In the case of bovine serum albumin gels, gelation involved transconformation of alpha-helix and aperiodic structures into beta-sheet conformation. Conditions that decreased the formation of beta-sheet structure decreased the gel strength. In the case of soy proteins, which contain mainly beta-sheet and aperiodic structures in the native state, only a reduction in the beta-sheet content and an increase in aperiodic structure content were observed in the gel state. It is hypothesized that, in globular protein gels, intermolecular hydrogen bonding between segments of beta-sheets oriented either in parallel or in antiparallel configurations may act as junction zones in the gel network.