Protein Quality of Selected Muscle Foods as Affected by the Exchange of Dietary Wheat Bran for Cellulose

The exchange of 8.4% neutral detergent fiber (NDF) of wheat bran for 8.3% NDF of cellulose in diets containing either beef, chicken, fish or casein as protein sources did not (P>0.05) alter feed consumption, weight gain or energy intake in the protein efficiency ratio (PER) bioassay with weanling rats. Higher (P<0.05) fecal nitrogen (N) excretions and lower (P<0.05) N digestibilities occurred for each protein source when wheat bran was exchanged for cellulose. The exchange also had no effect (P>0.05) on PER or net protein ratio (NPR) of casein or fish protein or on NPR of chicken protein. However, PER and NPR of beef and PER for chicken were reduced (P<0.05) when the dietary fiber was exchanged.     

Variations in Radiation Sensitivity of Foodborne Pathogens Associated with the Suspending Meat

Longissimus dorsi from beef, pork, and lamb and turkey breast and leg meats were inoculated with Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., and Staphylococcus aureus, and the gamma radiation resistance of the pathogens were determined under identical conditions. At 5°C the respective radiation D-values of E. coli O157:H7 and L. monocytogenes did not vary with the suspending meat. The D-value for a mixture of Salmonella spp. was significantly lower on pork than on beef, lamb, turkey breast, and turkey leg meats. The D-value for S. aureus was significantly lower on lamb and mechanically deboned chicken meat than on the other meats. All values were, nevertheless, within expected ranges.     

Bioavailability of Calcium from Sesame Seeds, Almond Powder, Whole Wheat Bread, Spinach and Nonfat Dry Milk in Rats

Calcium bioavailability (BV) from sesame seeds, almond powder, whole wheat bread, spinach, and nonfat dry milk (NFDM) was compared to calcium BV from a calcium carbonate (CaCO₃)-supplemented control diet using a rat model. When comparing different calcium sources, the relative BV of the products was CaCO₃ (100%), NFDM (100%) whole wheat bread (95%), almond powder (66%), sesame seeds (65%), NFDM and spinach mixture (52%), and spinach (47%). Separate almond, NFDM, and CaCO₃ diets were supplemented with 0.4% ascorbic acid; vitamin C addition had no significant effect on calcium BV.     

CHARACTERIZATION OF STOMACH AND PYLORIC CAECA PROTEINASES OF TAMBAQUI (COLOSSOMA MACROPOMUM)

The effects of pH, temperature, inhibitors, and substrates on proteolytic activities of crude extracts from the stomach, liver, pyloric caeca, and intestines of Colossoma macropomum were investigated. The highest acid and alkaline proteolytic activities were found in stomach and pyloric caeca, respectively. The optimum pH for the acid and alkaline proteases were 1.8 and 7.0–9.0, respectively, while the optimum temperatures were 35C and 65C. This alkaline protease thermal stability remained unaltered after 90 min incubation at 55C. A pepsin‐like protease was responsible for most of the acidic proteolytic activity (Pepstatin A inhibited approximately 90%), whereas PMSF inhibited about 40% of the alkaline protease. The alkaline proteolytic activity has attractive thermal properties for industrial applications.     

Influence of Poultry Species, Muscle Groups, and NaCl Level on Strength, Deformability, and Water Retention in Heat-Set Muscle Gels

The effects of poultry species (chicken and turkey), muscle groups (breast, thigh, and drum) and NaCl concentration (1% and 2%) on a low fat gel system were compared using measurements of shear stress (strength), shear strain (deformability), and two water retention measurements. Results showed doubling NaCl tended to double stress for all species and muscle groups and increased strain by 30–50%. Cross species differences showed higher stress in turkey gels than in chicken gels with 2% NaCl. For both species, stress, strain and water retention were lowest in breast gels with both NaCl concentrations, and strain was greater in thigh gels than in drum gels with 2% NaCl.     

Steam Surface Pasteurization of Beef Frankfurters

Meat and poultry products are sources of foodborne bacterial contamination. We used flash steam heating followed by evaporative cooling to quickly reduce bacterial contamination on the surface of beef frankfurters without degrading appearance. The rate of heat transfer was studied by measuring surface temperature in a pressure chamber during steam heating. Quality changes were determined by measuring color and weight as functions of steam temperature and treatment time. Efficacy of the process was verified by microbiological experiments using L. innocua. Treatment times of 30–40 set at 115–136°C gave a 4 log reduction in bacterial counts on the surface without severely affecting color or weight. After long-term storage at 6°C and at 19°C, levels of bacteria on inoculated frankfurters remained reduced and there was no difference between treated and untreated products in color or weight.     

Disruption of cellular translational control by a viral truncated eukaryotic translation initiation factor 2alpha kinase homolog

Phosphorylation of eukaryotic translation initiation factor 2alpha (eIF2alpha) is a common cellular mechanism to limit protein synthesis in stress conditions. Baculovirus PK2, which resembles the C-terminal half of a protein kinase domain, was found to inhibit both human and yeast eIF2alpha kinases. Insect cells infected with wild-type, but not pk2-deleted, baculovirus exhibited reduced eIF2alpha phosphorylation and increased translational activity. The negative regulatory effect of human protein kinase RNA-regulated (PKR), an eIF2alpha kinase, on virus production was counteracted by PK2, indicating that baculoviruses have evolved a unique strategy for disrupting a host stress response. PK2 was found in complex with PKR and blocked kinase autophosphorylation in vivo, suggesting a mechanism of kinase inhibition mediated by interaction between truncated and intact kinase domains.     

Molecular analysis of the adaptive response of intestinal bile acid transport after ileal resection in the rat

OBJECTIVES: Major operative trauma like aorta-coronary bypass operation may lead to postoperative immunodisturbance, putting the patient at an increased risk for infection and sepsis. The monocyte/macrophage system and the endotoxin receptor CD14 are important in the early recognition and elimination of invading bacteria. The aim of this study was to analyze changes in membrane-associated CD14 and soluble CD14 during and after cardiac involving cardiopulmonary bypass. METHODS: We studied numbers of leukocytes, monocytes, and monocyte subpopulations, expression of monocyte membrane-associated CD14 and plasma levels of soluble CD14 in 10 patients (63 +/- 8 years of age), who underwent elective cardiopulmonary bypass. RESULTS: Cardiopulmonary bypass induced marked postoperative monocytosis, which was maximal 20 hours after the operation (485 +/- 242 cells/microl before, 1080 +/- 264 cells/microl 20 hours after surgery). Expression of membrane-associated CD14 on classical CD14++ monocytes decreased significantly by 40%, reaching a nadir 20 hours after surgery (p < 0.05). At the time of maximal membrane-associated CD14 suppression, the levels of soluble CD14 measured by enzyme-linked immunosorbent assay were clearly increased (3.2 +/- 1.0 microg/ml before versus 5.6 +/- 1.0 microg/ml 20 hours after, p < 0.001). No significant change of the percentage of small (alpha) and large (beta) forms of soluble CD14 was found. CONCLUSIONS: Cardiopulmonary bypass leads to reduced membrane-associated CD14 expression on peripheral blood monocytes and increased levels of soluble CD14 through shedding or secretion of membrane-associated CD14 from the cell surface. These findings indicate that bypass is associated with significant monocyte activation.