Electron spin resonance spectra of γ-irradiated citrus fruit skins, skin components and stalks

The ESR spectra of the stalks and skins of a number of non-irradiated and γ-irradiated citrus fruits suggest that ESR spectroscopy could be used to establish the irradiation history. Two major spectral changes occur up on irradiation. Two additional features appear and are only observed in irradiated specimens (Features B and D, the latter separated by c. 5.9mT) and these are accompanied by an increase in the intensity of the main central signal (Feature A). Observations on the stability of Features A and D indicate that they arise from different radicals. Experiments on the meso- and exo-carps indicate that Features B and D are located mainly in the former and Feature A mainly in the latter.     

Microorganisms Isolated from Surimi Processing Operations

Heterotrophic bacteria isolated from two shore-based surimi processing plants in Alaska were identified to the genus level. In one plant, the major bacterial constituents were Flavobacterium and Pseudomonas, followed by Moraxella, Aeromonas, Lactobacillus, Serratia, and Acinetobacter. In the other plant, major bacterial groups were Flavobacterium and Arthrobacter/Corynebacterium, followed by Pseudomonas and Acinetobacter. Pseudomonas, Aeromonas, and Serratia were capable of rapid growth as low as 8°C, with respective generation times 3.0, 3.1, and 3.6 hours. Freezing and thawing of surimi reduced microbial counts to 45–67% of the pre-frozen load; however, the composition of the microbial flora was maintained. The plant environment was a potential source of microbial contamination.     

COOLING EFFECTS ON PROCESSED CHEESE FUNCTIONALITY

Textural and functional properties of processed cheese are affected by a final production step – cooling. Rheological data demonstrate a firmer cheese at slower cooling rates. To simulate industrial production, five‐pound cheese loaves were cooled in an environment at 5C under free and forced convection. Slice‐ability was estimated by cutting loaves at different locations using a wire‐cutting device, and melt‐ability was determined by the Schreiber method. Cooling rates, estimated from a heat transfer model, did not show a large difference within the five‐pound loaf, and no obvious trends in slice‐ability and melt‐ability were observed. Comparing forced with free convection, a smaller force was required to slice the cheese, and a higher melt score was experienced for the forced convection scenario. Cheese manufacturers can benefit from this research by manipulating cooling schedules to achieve desired textural attributes of processed cheese.     

PINK SALMON (ONCORHYNCHUS GORBUSCHA) QUALITY DURING ICE AND CHILLED SEAWATER STORAGE

Pink salmon were stored up to ten days in ice, chilled seawater (CSW), transferred from ice to CSW and from CSW to ice, and evaluated by chemical, physical, microbiological, and sensory methods. The sensory quality of CSW-held fish declined at a faster rate than for iced fish. CSW-held fish had higher weight gain, higher salt and hypoxanthine levels and had softer texture than iced fish. Microbial counts were highest for iced fish and a two-log increase occurred during storage. Moraxella species were predominant in the microbial flora of iced fish whereas Pseudomonas species were predominant in the microbial flora of CSW-held fish. Ice was superior to CSW for maintaining salmon quality.     

SOME FACTORS INVOLVED IN TRIMETHYLAMINE N-OXIDE (TMAO) DEMETHYLATION IN POST MORTEM RED HAKE MUSCLE

The pH optimum for demethylation of TMAO in minced red hake muscle at –5C was approximately 7.0. This value was higher than the pH optimum for the crude soluble enzyme in an anaerobic system utilizing flavin and NADH and for an aerobic system with ferric iron and ascorbate but was similar to the pH optimum observed with the flavin-NADH system in the presence of air. Both the anaerobic and aerobic flavin-NADH systems had sufficient activity in the presence of optimal concentrations of cofactors to account for all of the demethylation of TMAO observed in minced muscle. Comparison of concentrations of flavins and NADH and their rate of change during storage at temperatures both below and above freezing with previously determined kinetic constants suggest that this cofactor system may be critical in determining the rate of TMAO demethylation in post mortem red hake muscle. The extent of TMAO breakdown at –5C caused by the iron-ascorbate system was barely sufficient to account for the amount of DMA produced in the minced muscle. With the relatively low concentrations of iron and ascorbate present in the tissue, this system seems unlikely to be a major factor in TMAO degradation in situ.     

Crack-Interface Grain Bridging as a Fracture Resistance I, Mechanism in Ceramics: I, Experimental Study on Alumina

Direct microscopic evidence is presented in support of an explanation of R -curve behavior in monophase ceramics by grain-localized bridging across the newly formed crack interface. In situ observations are made of crack growth in tapered cantilever beam and indented flexure specimens of a coarsegrained alumina. The fractures are observed to be highly stable, typical of a material with a strongly increasing resistance characteristic, but are discontinuous at the microstructural level. Associated with this discontinuity is the appearance of overlapping segments in the surface fracture trace around bridging grains; the mean spacing of such "activity sites" along the trace is about 2 to 5 grain diameters. These segments link up with the primary crack beneath the specimen surface, and continue to evolve toward rupture of the bridge as fracture proceeds. The bridges remain active at large distances, of order 100 grain diameters or more, behind the crack tip. Scanning electron microscopy of some of the bridging sites demonstrates that secondary (interface-adjacent) microfracture and frictional tractions are important elements in the bridge separation process. Evidence is sought, but none found, for some of the more popular alternative models of toughening, notably frontal-zone microcracking and cracktip/internal-stress interaction. It is suggested that the crackinterface bridging mechanism may be a general phenomenon in nontransforming ceramics.     

Microorganisms on Commercially Processed Alaskan Finfish

Whole and processed Alaskan fish were examined for aerobic plate counts, total coliforms, and Escherichia coli. Washing whole salmon and halibut reduced skin microbial counts from 10³/cm² to 10²/cm². Whole and dressed fish had coliform counts less than 13/cm² and E. coli counts less than 0.3/cm². Alaska pollock and Pacific cod fillets had microbial counts between 10³/g and 10⁶/g, coliform counts less than 70/g, and E. coli counts less than 4/g. Whole fish contained microbial flora predominated by Moraxella species whereas dressed fish and fillets had microbial flora consisting of Arthrobacter/Corynebacterium, Flavobacterium, and Pseudomonas species. Microorganisms on conveyor belts and other contact surfaces may have contributed contaminants to fillets.     

GENDER,CAMPAIGN FINANCE,AND ELECTORAL SUCCESS IN MUNICIPAL ELECTIONS

ABSTRACT: Despite high success rates when they run for office, women are still underrepresented in federal, state, and local elective office. Past research has explored factors that contribute to the scarcity of female candidates on the state and federal level, but little attention has been paid to the local level. This article begins to fill that gap by exploring electoral and fundraising patterns in mayoral and council elections in seven cities. We find that, similar to state and federal elections, women do just as well as men when they seek office but fewer women run. Further, of the women who do mount campaigns their backgrounds are quite similar to male candidates, raise comparable amounts of campaign funds, and receive contributions from the same sources. In general, we found few differences between male and female candidates. These findings highlight the importance of self‐selection in the decision to run for office.     

Indentation Deformation and Fracture of Sapphire

Relatively little is known about the fundamental deformation processes in intrinsically hard, brittle materials, and even less about how these processes lead to the initiation of cracks. In this paper, transmission electron microscopy is used to study the deformation structure within Vickers indentation zones of single-crystal sapphire with {     } surface orientation. The relative misorientation of regions within these zones, as mapped by convergent-beam kikuchi patterns, is found to be severe, indicative of shear processes operating close to the cohesive limit. Two principal types of deformation are identified, basal twinning and pyramidal slip. Incipient microcracks are observed at both the twin interfaces and the slip planes. These incipient "flaws" act as nucleation sites for the ensuing radial and lateral cracks.     

Effects of pH on Calcium, Zinc, and Phytate Solubilities and Complexes Following In Vitro Digestions of Soy Protein Isolate

High intraluminal gastric pH values in young infants could affect the bioavailability of zinc in soy protein isolate formula. This investigation examined the effects of pH on the solubilities and complexes of calcium, zinc and phytate following in vitro pepsin and pepsin-pan-creatin digestions of soy protein isolate. The results of these in vitro studies suggested that (1) high intraluminal gastric pH values could lead to the formation of insoluble calcium-zinc-phytate complexes in the stomach following ingestion of soy protein isolate and (2) high intraluminal gastric pH values would only affect resultant soy zinc solubility in the small intestine in the absence of exogenous calcium or zinc but not in the presence of same.