Surimi-based product development and viscous properties of surimi paste

• Main Author: Bouraoui, Moez Mohamed
• Format: Thesis
• Language: English
• Published: 1996
• Subjects: Pacific; Pink salmon
• Online Access: http://hdl.handle.net/2429/6246

Raman spectroscopy was used to study the protein structure in raw and salted surimi from Pacific whiting, and in gels formed by setting (32°C), cooking (86°C) or setting followed by cooking. The intensity of the peaks assigned to disulfide bond stretching vibrations increased considerably in the cooked and set-cooked gels. A smaller increase was found in the gels that were subject to setting alone. Secondary structure estimation based on the amide I band indicated a change from predominantly a-helical structure in raw surimi to similar proportions of a-helical and anti-parallel p-sheet after setting. A further increase in anti-parallel p-sheet and decrease in a-helix content occurred during the kamaboko stage. The intensity of C-H stretching vibrations of the aliphatic residues decreased after salting, setting and cooking. The set and cooked gel had a better gel strength and fold score than the cooked gel which, in turn, had better properties than the set gel. Response surface methodology was used to determine the optimal setting and cooking time and temperature conditions resulting in a maximized gel strength, fold score and color, (whiteness index), and a minimized gel expressible liquid. Cooking temperature was the variable that had the strongest influence on the gel quality characteristics. Level set programming, a global optimization method, gave essentially the same results as a gradient based optimization method. The results obtained by these two methods were better than those generated by the Simplex technique. Using a formulation composed of pink salmon surimi, salt, whey protein concentrate and wheat starch, an optimal final product, kamaboko sausage, was developed. In addition, when this formulation was applied to herring surimi, the kamaboko obtained had similar gel strength and elasticity as a commercial surimi-based product. The effects of frozen storage conditions of roe herring on its gel making ability (GMA) were investigated. Frozen storage at around -45°C maintained the GMA for seventy days while storage at -83°C further increased the GMA period. The viscous properties of a salmon surimi paste were studied using a rotational viscometer. The paste behaved as a shear thinning fluid with a yield stress that increased with temperature up to 21 °C. Viscosity also increased with temperature up to 21 °C, possibly because of protein-protein interactions. The Theological data were reasonably well represented by a simple model which takes into consideration the effects of both shear rate and temperature. Applied Science, Faculty of Chemical and Biological Engineering, Department of Graduate