Rheological and physicochemical evaluation of thermal gelling of surimi from silver catfish

Abstract

^{The objective of this work was to evaluate the rheological and physicochemical properties of thermal gelling of surimi from silver catfish (Rhamdia quelen). Four heating treatments were used: one-step heating at 90oC, for 15 min, was compared with three two-step treatments with pre-heating at 60oC for 30, 45 and 60 min, followed by heating at 90oC for 15 min. Each heat treatment was used on three formulations: two with protease inhibitors (bovine serum albumin + alpha2-macroglobulin and egg white) and a formulation without inhibitors. Samples with inhibitors and one-step heating reached better gelling, by an increase in the storage modulus and a decrease in phase angle. Pre-heated gels had large variation in viscoelastic parameters which interfered with the establishment of the protein network during thermal gelling of surimi. The soluble peptides concentrations did not change significantly, even when two-step heating was carried out, which indicates absence of proteolysis, besides showing protein network protection by inhibitors.}