Bigeye Snapper Surimi Research Articles

Gelation characteristics of tropical surimi under water bath and ohmic heating

Gelation characteristics of tropical surimi, namely threadfin bream (TB), bigeye snapper (BS), goatfish (GF) and lizardfish (LF) prepared in the absence and presence of 10gkg−1 egg white proteins were evaluated using either ohmic (OH) or water bath (WB) heating. LF and GF surimi exhibited higher endogenous proteolytic activity than BS and TB. Ohmic heating markedly minimized proteolysis of LF and GF surimi as evidenced by a reduction of trichloroacetic acid (TCA)-soluble oligopeptide content of gels and more retention of myosin heavy chain (MHC). Ohmic heating increased breaking force and deformation of TB and BS surimi by 1.3 and 1.6 times, respectively, as compared to water bath heating. However, TB surimi gels heated by a higher applied voltage gradient of 16.7Vcm−1 exhibited lower breaking force than those heated at 6.7Vcm−1. Gels heated ohmically contained lower total sulfhydryl concentration, indicating the greater extent of disulfide bond formation as compared to gels heated in a 90°C water bath. The rapid heating method with shorter heating time could improve water holding capacity and preserve color of tropical surimi gels when compared to water bath heating.

Chicken plasma protein affects gelation of surimi from bigeye snapper ( Priacanthus tayenus)

Effect of chicken plasma protein (CPP) at different concentrations on gel properties of grade SA and A bigeye snapper surimi was investigated. Addition of 0.5% CPP in combination with setting at 40 °C for 30 min prior to heating at 90 °C for 20 min resulted in the highest breaking force and deformation ( P<0.05). However, whiteness decreased to some extent. CPP was able to prevent the degradation of surimi proteins as indicated by the decrease in TCA-soluble peptides ( P<0.05). Electrophoretic studies revealed that myosin heavy chain underwent polymerization to a lower extent as CPP concentration increased. Therefore, CPP worked as protease inhibitor rather than protein cross-linker. Microstructure of kamaboko gels, added with 0.5% CPP, had less linkage between protein strands with a coarser fibrillar structure, indicating the interfering effect of CPP on cross-linking of myofibrillar proteins. Thus, at an appropriate amount, CPP possibly worked as a filler in the surimi gel matrix, resulting in gel strengthening.

Transglutaminase-mediated setting in bigeye snapper Surimi

Effect of setting induced by endogenous transglutaminase (TGase) in two species of bigeye snapper, Priacanthus tayenus and Priacanthus macracanthus, on gel properties and protein cross-linking was investigated. Setting at either 25 or 40 °C, prior to heating at 90 °C resulted in the increase in both breaking force and deformation of surimi from both species, particularly when setting time increased ( P<0.05). A decrease in solubility of surimi gels in a mixture of sodium dodecyl-sulfate, urea and β-mercaptoethanol suggested increased formation of non-disulfide covalent bonding which coincided with increased gel strength and the decrease in myosin heavy chain (MHC) polypeptide. The optimum conditions for setting of surimi sol was found to be 40 °C for 2 h for P. tayenus and 25 °C for 3 h for P. macracanthus. Assayed by monodancylcadaverine (MDC)-incorporation method, TGase from P. tayenus and P. macracanthus exhibited an optimum temperature at 40 and 25 °C, respectively. In addition, the breaking force and deformation of surimi from both species increased markedly with the addition of calcium chloride, while they decreased considerably in the presence of EDTA, N-methylmaleimide and ammonium chloride. The results confirmed that endogenous transglutaminase played an important role in gel enhancement of surimi from both species of bigeye snapper.