Solubility of Salmon Myosin as Affected by Conformational Changes at Various Ionic Strengths and pH

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 <4. The increased solubility correlated with the increased surface hydrophobicity and relative sulfhydryl content as well as the decreased α-helicity. At KCl >1.0M, myosin regained its helix structure with a concomitant loss of solubility due to the dominant hydrophobic interaction among nonpolar amino acid residues.     

FEEDING LOW CALCIUM AND ZINC MOLT DIETS SUSTAINS GASTROINTESTINAL FERMENTATION AND LIMITS SALMONELLA ENTERICA SEROVAR ENTERITIDIS COLONIZATION IN LAYING HENS

The objective of these experiments was to determine whether alternative molting diets would minimize Salmonella enterica serovar Entertitidis (S. Enteritidis) colonization in molting hens. Hens were randomly assigned to four treatment groups of 12 hens either full‐fed (nonmolt, NM), molted by feed withdrawal (molt, M), a low calcium (LC containing 800 mg calcium), or LC diet supplemented with 110 mg zinc/ kg of diet (LC‐ZN) in two trials. All hens were challenged orally with 10 ⁵SE on day 4 of experiment. Hen body weight loss was significantly (P < 0.05) increased and ovarian weight was significantly (P < 0.05) decreased in hens fed the LC or LC‐ZN diets compared to NM. Cecal lactic acid concentrations were significantly (P < 0.05) increased in hens fed alternative molting diets. Feed withdrawal molted hens exhibited significantly (P < 0.05) more S. Enteritidis positive and S. Enteritidis crop, cecal, and organ colonization than NM, LC and LC‐ZN hens. Alternative molt diets retain sufficient fermentative activity to limit S. Enteritidis colonization and therefore may have potential to avoid the risk of increasing S. Enteritidis colonization associated with feed withdrawal.     

Characterization of functionally gradient epoxy/carbon fibre composite prepared under centrifugal force

Centrifugal force was employed in order to induce a spatial gradient of fibre distribution in the epoxy/carbon fibre system. The gradient structure of the epoxy/carbon fibre composite can be controlled by varying the rotation time and the material parameters, such as fibre length, fibre content and matrix viscosity. The spatial gradient distribution of carbon fibres in an epoxy matrix was achieved by the combined mechanism of packing and settling. The mechanical properties of the functionally gradient epoxy/carbon fibre composite were also investigated. At the same content of carbon fibre, the flexural strength of the functionally gradient composite was higher than that of conventional isotropic composite. This revised version was published online in November 2006 with corrections to the Cover Date.     

Moisture, Total Fat and Cholesterol in Goat Organ and Muscle Meat

Moisture, total fat and cholesterol of goat liver, kidney, heart, Longissimus dorsi (LD) and Biceps femoris (BF) muscles were determined. Samples were taken from 10 Alpine and 10 Nubian post-weaned goat kids that were fed a complete diet treated with 4 levels of Ca for 12 wk before slaughter. Mean moisture (%), total fat (%) and cholesterol (mg/100g wet tissue) for the respective tissues were: 75.9, 3.26, 214.2; 82.0, 3.14, 276.7; 79.2, 4.32,167.5; 79.2, 2.27, 57.8; 80.4, 2.03, 69.5. These goats contained less cholesterol in liver and more cholesterol in kidney and heart than the same organs in mutton samples reported previously. Fat and cholesterol were significantly (P < 0.01) influenced by dietary Ca, breed and tissue, while moisture was affected only by tissue.     

Rheological Behavior and Potential Cross-Linking of Pacific Whiting (Merluccius productus) Surimi Gel

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°C setting followed by 90°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.