Surimi-Starch Interactions Based on Mixture Design and Regression Models

Interaction effects of starch mixtures within surimi gels were investigated by modified distance-based design and analyzed by linear and nonlinear backward regression models. Nonlinear regression model showed highly significant interaction terms of starch-surimi, starch-water, and starchstarch. The response trace plot revealed that shear stress and shear strain were quite sensitive to changes in amounts of starch components. Optimum solution with combinations of various starches, surimi, and water was provided using linear and nonlinear programming.     

Effect of preparation conditions on the formation of primary ZnO particles in filter expansion aerosol generator

Abstracts are not published in this journal     

Fabrication of cast carbon steel with ultrafine TiC particles

The carbon steels dispersed with ultrafine TiC particles were fabricated by conventional casting method. The casting process is more economical than other available routes for metal matrix composite production, and the large sized components to be fabricated in short processing time. However, it is extremely difficult to obtain uniform dispersion of ultrafine ceramic particles in liquid metals due to the poor wettability and the specific gravity difference between the ceramic particle and metal matrix. In order to solve these problems, the mechanical milling (MM) and surface-active processes were introduced. As a result, Cu coated ultrafine TiC powders made by MM process using high energy ball milling machine were mixed with Sn powders as a surfactant to get better wettability by lowering the surface tension of carbon steel melt. The microstructural investigations by OM show that ultrafine TiC particles are distributed uniformly in carbon steel matrix. The grain sizes of the cast matrix with ultrafine TiC particles are much smaller than those without ultrafine TiC particles. This is probably due to the fact that TiC particles act as nucleation sites during solidification. The wear resistance of cast carbon steel composites added with MMed TiC/Cu-Sn powders is improved due to grain size refinement.     

EXTENDING THE SHELF LIFE OF SET FISH BALL

Set fish ball is an extruded surimi‐based product that is popular in Singapore and other Southeast Asian countries. Oversetting of set fish ball occurs at chilled temperature during storage. Shelf‐life extension of set fish ball by reducing oversetting conditions and microbial counts were examined. Encapsulated citric acid (CT) and glucono‐delta‐lactone (GDL) were used to reduce oversetting. Acetic acid, GDL and chitosan were used to inhibit the growth of microorganisms. Shelf life was measured for a period of 21 days at 4C. At day 21, a reduction of 46, 56 and 26% in breaking force compared with the control (without additives) was observed for 0.5% GDL, 1.0% GDL and CT, respectively. GDL at 1.0% was shown to be the most effective in controlling the oversetting of set gel. Chitosan (1%) dissolved in acetic acid maintained both aerobic plate and yeast counts at <1 log cfu/g throughout 21 days of storage.     

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.