Calcium Compounds to Improve Gel Functionality of Pacific Whiting and Alaska Pollock Surimi

The effect of calcium compounds during three thermal treatments with or without setting was studied. Formation of cross-linking was investigated using SDS-PAGE. Solubility varied. Calcium acetate, chloride, and caseinate were extremely soluble. Calcium lactate had good solubility at 0.2% or higher, then in descending order were phosphate, citrate, sulfate, and carbonate. Effects of temperature on solubility were not measurable except for caseinate. When 25°C setting was applied to surimi, calcium was most effective. Effect of calcium on shear stress was dependent on species, setting temperature, and specific compound. SDS-PAGE indicated that improved gel functionality was likely due to Ca++-dependent trans-glutaminase.
Read More

Characterization of rheological and physicochemical properties of Alaska walleye pollock (Gadus chalcogrammus) roe

Alaska walleye pollock (Gadus chalcogrammus) roe is a commercial product of the Alaska pollock fishery. Accordingly, the objective of this study was to determine functional properties of pollock roe through rheological and physicochemical analyses. Pollock roe rheological properties were determined by flow sweep and frequency sweep measurements. Zeta potential of the roe was measured at different pHs (2-12) and roe protein concentration of 0.05% (w/v). Protein solubility was determined by adjusting pH of the freeze-dried pollock roe powder between 2 and 12. Emulsion stability of the roe was determined by measuring creaming index at different oil:water ratios ranging from 5:95
Read More

Chemical Composition and Texture of Commercial Geoduck Clams (Panopea abrupta) Harvested in Southeast Alaska

The objectives of this study were to determine chemical composition of the siphon and the mantle of commercialsize geoducks clams harvested in Southeast Alaska, and to measure textural differences between the two muscle tissues, comparing them with their frozen counterparts. Live geoducks were processed using standard industry practices and analyzed either fresh or after 90 days of frozen storage. The mantle significantly differed in composition and texture from the siphon. The mantle had significantly higher contents of carbohydrates and lipids, whereas the siphon had a higher moisture content. Protein content was similar between tissues, but soluble protein content in the
Read More

Development of a method to produce freeze-dried cubes from 3 Pacific salmon species

Freeze-dried boneless skinless cubes of pink (Oncorhynchus gorbuscha), sockeye (Oncorhynchus nerka), and chum (Oncorhynchus keta) salmon were prepared and physical properties evaluated. To minimize freeze-drying time, the kinetics of dehydration and processing yields were investigated. The physical characteristics of the final product including bulk density, shrinkage, hardness, color, and rehydration kinetics were determined. Results showed that freeze-dried salmon cubes from each of the 3 Pacific salmon species can be produced with a moisture content of less that 10% and a(w) less 0.4 and freeze-drying time of 9 h. Processing yields ranged from 26% to 28.4%, depending on fish species. Shrinkage
Read More

Effects of nano-scaled fish bone on the gelation properties of Alaska pollock surimi

Gelation properties of Alaska pollock surimi as affected by addition of nano-scaled fish bone (NFB) at different levels (0%, 0.1%, 0.25%, 0.5%, 1% and 2%) were investigated. Breaking force and penetration distance of surimi gels after setting increased significantly as NFB concentration increased up to 1%. The first peak temperature and value of storage modulus (G′), which is known to relate to the unfolding and aggregation of light meromyosin, increased as NFB concentration increased. In addition, 1% NFB treatment demonstrated the highest G′ after gelation was completed. The activity of endogenous transglutaminase (TGase) in Alaska pollock surimi increased as NFB
Read More

Functional Protein Additives in Surimi Gels

Medium-grade Alaska pollock surimi was used to investigate the effects of functional protein additives on texture and colors. Torsion failure and differential scanning calorimetry tests were applied to measure gel strength, gel deformability, and calorimetric properties. CIE Lab color values were also measured. Shear stress values of gels and peak temperature of DSC thermograms were all increased. Shear strain, a good indicator of protein-protein interaction, was increased only by addition of egg white and beef plasma protein. Yellowness (b*) values were affected by all additives except frozen egg white. Whiteness index (L*-3b*) was a more effective indicator to differentiate additives.
Read More

Physicochemical Changes in Alaska Pollock Surimi and Surimi Gel as Affected by Electron Beam

Alaska pollock surimi and surimi gels (cooked) were subjected to various doses of electron beam (e-beam). Shear stress of surimi gels increased as the dose increased up to 6 to 8 kGy and then decreased. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed gradual degradation of myosin heavy chain as the dose increased. The degradation was slower for frozen samples. The integrity of actin was slightly affected by high doses (25 kGy). The amount of sulfhydryl groups and the level of surface hydrophobicity of Alaska pollock surimi decreased as the dose increased, suggesting formation of disulfide bonds and hydrophobic interactions. The
Read More

Quality of Alaskan Maricultured Oysters (Crassostrea gigas): A One-Year Survey

The objective of this project was to provide relevant information to Alaska shellfish growers regarding the intrinsic quality of their farmed oysters. A 1-y study was conducted to determine the condition indices, proximate composition, fatty acid content, and microbial load of commercially harvested oysters from 3 different mariculture regions in the state of Alaska. Oysters from farms located in the regions of Prince William Sound, Kachemak Bay, and Southeast Alaska were sampled according to the farmers' harvest schedules. Our results suggest that Alaskan maricultured oysters have slight seasonal and regional differences. The condition indices of Alaska oysters were high, indicating
Read More