29C-16 |
Physical properties of pressurized and heat-treated surimi gels as affected by potato starch and egg white |
G. TABILO-MUNIZAGA and G. V. Barbosa-Cánovas. Dept. of Biological Systems Engineering, Washington State Univ., PO Box 646120, Pullman, WA 99164-6120 To assess whether or not HHP technology is a suitable alternative to processing surimi, it is essential to compare the physical properties of gels obtained in both approaches. Physical properties of Alaska pollock and Pacific whiting surimi gels treated by HHP (400MPa and 650MPa, 10min) as affected by potato starch (4%) and egg white (1%) and compared with results from heat-treated gels (90oC, 40min) were studied. In order to determine the textural parameters, a compression test, penetration test, and TPA test were carried out. SEM was used to examine the gel structure. WHC and CIE L*, a*, b* values were also measured. Heat-treated gels showed an opaque white color while pressurized gels were more translucent. Lightness (L*) values were reduced by pressure whereas whiteness (L*-3b*) values increased with a reduction of b* values. Pollock gels showed an increase of gel strength with pressure treatment when compared to heated gels with or without additives. However, whiting gels a decrease in gel strength was observed. SEM showed that the protein-protein matrix was fibrous and homogenous with a three-dimensional network structure, whereas the protein-starch matrix showed a more compact and continuous matrix. When potato starch was added, the integrity of some starch granules was maintained, suggesting that potato starch was resistant to high-pressure treatment regardless of pressure level. Additives slightly affected WHC and high values (over 90%) were obtained in all treatments. Pressurized Pacific whiting surimi gels at both levels (400MPa and 650MPa) with added egg white was more effective in reducing weight loss as compared to heated gels. High hydrostatic pressure treatments can be used as an alternative to thermal treatments for the processing of surimi-based products. Since HHP produces a surimi gel with a finer surface and smoother characteristics, a range of novel products could be produced.
Session 29C, Food Engineering: Rheology and texture
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