Physical, Chemical and Sensory Changes in Irradiated Fresh Pork Packaged in Modified Atmosphere

The effects of irradiation dose (0, 0.5 and 1.0 kGy), headspace oxygen (0, 10 and 20% O₂, balance nitrogen) and storage temperature (5, 15 and 25°C) on the physical, chemical and sensory changes in fresh pork were studied using factorial design experiments. Irradiation in the absence of oxygen extended the sensory shelf life of pork from 9 to 26 days at 5°C and from & lt; 2 to 2 days at 25°C. Oxygen in the package headspace combined with irradiation adversely affected physical, chemical and sensory characteristics of the end product.     

Modified Atmosphere Packaging Affects Ascorbic Acid, Enzyme Activity and Market Quality of Broccoli

Reduced ascorbic acid (RAA) content, total chlorophyll and green color retention, enzyme activities and texture changes were followed in broccoli spears packaged in polymeric film and nonpackaged during 96 hr storage (10°C). Concentrations within packages monitored by gas chromatography were (CO₂,) 8% and (0²) 10%. RAA retention, moisture content, total chlorophyll and color retention were greater in packaged broccoli. No differences were found between packaged and nonpackaged broccoli for ascorbate oxidase and peroxidase activities, or texture.     

Nonlinear Variation of Refractive Index of Vitreous Silica with Pressure to 7 Kbars

The variation of refractive index of vitreous silica with purely hydrostatic pressure to 7 kbars was determined from the shift of the localized interference fringes across the specimen kept in an optical pressure bomb. Allowance for the change in the thickness of the specimen was made with the help of Murnaghan's finite-strain theory and the recently determined third-order elastic constants. The refractive index for λ 5893 A increases linearly with pressure with a slope of 9.2 × 10⁻⁴/kbar up to 4 kbars; thereafter it increases nonlinearly. The increase in the refractive index, however, is linear with respect to the Lagrangian strain in the range investigated, except for a slight tendency for departure from linearity at the highest pressures. No hysteresis effects caused by permanent densification were noted. The results are interpreted in the light of Mueller's theory of photoelasticity of amorphous solids.     

Thermochemistry of MgAl2O4-Al8/3O4 Defect Spinels

Solution calorimetry of MgAl₂O₄-Al_8/3O₄ solid solutions was performed in a molten 2PbO · B₂O₃ solvent at 975 K. The results indicate small negative heats of mixing, relative to spinel standard states for both end-members. These data were combined with information on the energetics of the α-γ transition in Al₂O₃ and on the MgAl₂O₄-Al_8/3O₄ (MgO-Al₂O₃) subsolidus phase relations to estimate the partial molar entropy of mixing of γ-Al_8/3O₄ in the solid solution. This entropy is much less positive than that calculated from several models for the configurational entropy of mixing of magnesium, aluminum, and vacancies on octahedral and/or tetrahedral sites. The data suggest a good deal of local order to be present in the solid solutions, consistent with negative enthalpies of mixing and entropies of mixing far less than ideal configurational values.     

Comments on ‘The phenomenon of homeopathic instability in dynamical systems’

Less restrictive sufficiency conditions on system parameters are developed for the existence of homeopathic instability in the class of dynamical systems considered by Johnson. With these conditions, the results are consistent with the earlier work of Youla el at., in particular in terms of the pole-zero interpretation of the sufficiency conditions. A typographical error in the work by Johnson is also noted.     

EXTENDED VALIDATION OF A SIMPLIFIED EXTRACTION AND GRAVIMETRIC DETERMINATION OF TOTAL FAT TO SELECTED FOODS

A simplified method for chloroform/methanol extraction and gravimetric determination of total fat previously published for diet composites was tested on additional foods, including milk, cheese, fried snack foods, nuts/seeds, salad dressings, baked goods, meat, fish/shellfish and fruits/vegetables. Homogenized food composites and certified reference materials (CRMs) were analyzed using the existing method involving, briefly, orbital shaking of a subsample with chloroform/methanol/buffer in specific proportions, then recovery of total lipid in the chloroform extract. For meat, fish, shrimp, cheese and fried plantains, total fat recovery was low and/or variability was high with the unmodified assay versus results from other standard total fat methods (e.g., ether extraction, acid hydrolysis) or to CRM assigned values. Reducing the sample size or adding a homogenization step during extraction resulted in relative standard deviations of < 3% for all matrices and also values consistent with those generated by other standard total fat methods and within assigned ranges for total fat in most CRMs.

PRACTICAL APPLICATIONS

The method allows for routine batch analysis of multiple samples of a range of food types with minimized hands-on time, using commonly available laboratory equipment. The resulting total lipid extract can be subdivided for analysis of various specific lipid analytes as well as for gravimetric measurement of total fat.     

DESENSITIZATION AND THE EXPERIMENTAL REDUCTION OF THREAT.

TESTED A SYSTEMATIC DESENSITIZATION PROCEDURE AND 2 OF ITS COMPONENTS FOR ABILITY TO REDUCE STRESS RESPONSES OF 58 MEN AND 51 WOMEN IN A LABORATORY THREAT SITUATION. SS RECEIVED 1 OF 4 TYPES OF TRAINING PROCEDURES BEFORE EXPOSURE TO A STRESSFUL FILM: AN ANALOGUE OF THERAPEUTIC DESENSITIZATION, RELAXATION, COGNITIVE REHEARSAL, OR NO TRAINING CONTROL. STRESS RESPONSE DURING THE SHOWING OF A DRAMATIC FILM ON INDUSTRIAL ACCIDENTS WAS MEASURED BY CONCURRENT SELF-REPORT, HEART RATE, AND SKIN CONDUCTANCE MEASURES. RESULTS SHOWED THAT THE SEPARATE COMPONENTS OF DESENSITIZATION, RELAXATION AND COGNITIVE REHEARSAL, WERE AS EFFECTIVE ALONE AS WHEN COMBINED IN THE COMPLETE DESENSITIZATION PROGRAM. ON SEVERAL MEASURES, COGNITIVE REHEARSAL APPEARED TO BE THE MOST EFFECTIVE THREAT REDUCER. (26 REF.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of Washing Treatment on Quality of Minced Mullet Flesh

Washing treatments were evaluated for quality improvement of minced mullet. Thiobarbituric acid (TBA) number generally decreased with increased washing temperature from 5–35°C and increased at higher temperatures. At 35°C, a wash water pH of 6.0 or above resulted in decreased TBA number. Response surface analysis indicated maximum whiteness index, minimum TBA number, and minimum cooking loss with washing at 29–33°C for up to 10 min with a water to flesh ratio from 23–26. Highest springiness was indicated with washing ratio of 25 to 30 at 28–31°C The simultaneously optimized washing conditions for highest minced mullet quality were 31.4°C for 7.5 min at a ratio of 24.     

ON THE DYNAMICS OF PERIODICALLY FORCED CHEMICAL REACTORS†

A method for studying the dynamics of periodically forced chemical reactors is presented along with the appropriate numerical techniques for its implementation. The method is capable of routinely treating many characteristics of forced oscillatory systems such as subharmonic and related bifurcations, bifurcations to invariant tori and frequency locking. It involves direct solution for the fixed points of the stroboscopic map. This procedure is particularly suitable for detecting certain routes to deterministic chaos such as the Feigenbaum period doubling cascade. Some illustrative examples from a homogeneous catalytic reactor model are included.