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The relationship between solubility and conformational changes of salmon (Oncorhynchus tshawytscha) myofibrillar proteins at various ionic strengths and pH was investigated using myosin as a model system. Solubility of myosin increased with increased KCl concentration up to 0.5M. Further increasing salt concentration resulted in a gradually reduced solubility. In the absence of salt, myosin was slightly soluble at pH>7 or 1.0M, myosin regained its helix structure with a concomitant loss of solubility due to the dominant hydrophobic interaction among nonpolar amino acid residues.

Physical and sensory properties of vacuum microwave dried shrimp were evaluated and compared with those of air and freeze dried samples. Samples prepared by vacuum microwave drying of 4 kW, 100 mm Hg (V4-1) had less shrinkage as well as higher rehydration potential (RP) and water retention ability (WRA) than air dried samples. Reducing microwave power or increasing pressure resulted in higher shrinkage and tougher texture with losses of RP and WRA. Although inferior in structure retention, RP, and WRA, rehydrated V4-1 shrimp were comparable in sensory ratings for color, texture, aroma/flavor, and overall acceptability to the rehydrated freeze dried samples.

Vacuum microwave drying of carrot slices was compared to air drying and freeze drying on the basis of rehydration potential, color, density, nutritional value, and textural properties. Vacuum microwave dried (VMD) carrot slices had higher rehydration potential, higher α-carotene and vitamin C content, lower density, and softer texture than those prepared by air drying. Carrot slices that were air dried (AD) were darker, and had less red and yellow hues. Less color deterioration occurred when vacuum-microwave drying was applied. Although freeze drying of carrot slices yielded a product with improved rehydration potential, appearance, and nutrient retention, the VMD carrot slices were rated as equal to or better than freeze dried (FD) samples by a sensory panel for color, texture, flavor and overall preference, in both the dry and rehydrated state.

Manufacturing technology of surimi and surimi seafood has been developed to keep the balance of the quality and quantity (yield) of surimi proteins. This review article covers the chemistry of surimi manufacturing with an emphasis on solubility of myofibrillar proteins as affected by ionic strength, pH, washing cycles, wash/meat (W/M) ratio, and proteolysis. In addition, water quality, waste water, and cryoprotection are reviewed. Ohmic heating and high hydrostatic pressure in relation to the manufacturing of surimi seafood are extensively discussed. Ohmic heating is the newest technology applied in the manufacturing of surimi seafood. High hydrostatic pressure has not been applied in the commercial practices of surimi seafood manufacturing, however, it has a great potential to make surimi gels stronger.

Possible minimization of water usage for leaching was investigated by reduced water/meat (W/M) ratio with increased washing cycles (WQ and washing time (WT). Increased WT did not enhance removal of sarcoplasmic proteins once equilibrium was reached, while the increased WC continuously removed residual sarcoplasmic proteins from the mince. No significant loss of myoFibrillar proteins occurred at the low W/M ratio (2:1 or 1:1) regardless of WC and WT. Myosin heavy chain content, water retention, and whiteness of washed mince decreased when W/M ratio was reduced. Increasing WC and/or WT enhanced these properties but also resulted in a higher moisture content.

Gulf of Mexico butterfish (Peprilus buri), a largely unutilized fishery resource, has been examined for its application as a food-grade marine product. Butterfish mince prewashed with sodium bicarbonate solution (0.5%) had lower lipid oxidation and free fatty acid (FFA) content than unwashed mince during a 6-month frozen storage study. Washed mince also exhibited a lower Hunter a value and had superior water retention. Addition of Tenox 2 or vacuum packaging further reduced lipid oxidation and FFA liberation. This reduction also prevented the subsequent lipid-protein interaction as indicated by increased water retention.

The effects of post-harvest storage temperatures and times on proteolysis of Pacific whiting (Merluccius productus) and relationship to changes in protein solubility were evaluated. Myosin heavy chain (MHC) degraded rapidly during post-harvest storage at low temperatures (0-5°C). Greater degradation of MHC occurred at elevated temperatures. Actin degradation was similar to that of MHC but to a lesser degree. Both log-percent MHC and actin degradation were highly correlated (R2 5 0.88 and 0.74) to protein solubility. Degraded proteins were not completely removed by washing, resulting in a lower MHC content in washed mince.

Effects of salt concentrations and washing cycles on the extraction of proteins were evaluated. Sarcoplasmic proteins were readily soluble in water (0% NaCI) and removed in the initial washing steps. Myofibrillar proteins became relatively soluble and were lost during extensive washing. Control of water/meat ratio, washing time, and washing cycles was critical in reducing the loss of myofibrillar proteins. Washing with 0.25%, 0.5%, and 1.0% NaCl solutions reduced the loss of myofibrillar proteins. However, these solutions were not very effective in removing sarcoplasmic proteins even with increased washing cycles. High salt (2.0% NaCl) washing resulted in low removal of sarcoplasmic proteins and severe loss of myofibrillar proteins.

Micro- and ultrafiltration were utilized for recovery of proteins and for water recycling from commercial surimi processing waste water. The proteins recovered by microfiltration showed highly functional properties and composition comparable with proteins in regular surimi. Surimi with a substitution (10%) of recovered proteins did not diminish in gel hardness, elasticity, color, or water retention. Aerobic plate count, chemical oxygen demand, protease activity, and turbidity in the surimi waste waters were reduced by ultrafiltration. Results indicated a potential for re covering proteins to extend yield and recycling water

Gelation behavior and potential cross-linking of Pacific whiting (Merluccius productus) surimi were affected by setting temperatures and an enzyme inhibitor. Gels of Pacific whiting surimi with salt and beef plasma protein were compared with those containing guanidine hydrochloride, sodium dodecyl sulfate, and β-mercaptoethanol. The strongest gels were formed at 25 o C setting followed by 90 o C heating. Hydrogen and hydrophobic bonds appeared to strongly influence gel formation, while the influence of disulfide bonds was moderate. Viscosity scanning during setting at different temperatures was also useful to estimate effects of enzymes and inhibitors