Aseptic Processing of Beef Particulates: Flavor Development/Stability and Texture

A laboratory thermal processing unit and reactor cell were adapted to aseptically process browned and unbrowned cubes from Choice an Utility Grade beef. Processing parameters of heating medium flow rate, time and temperature were established. Processed product was analyzed for changes in flavor and texture on day 0 and after 30 days refrigerated storage. Because sterility of each sample was not verified, sensory evaluation was only performed at day 0. Pre-browning improved flavor quality and did not reduce tenderness or yield. Low quality beef could be effectively utilized with proper processing parameters. Lipid oxidation and loss of sulfur compounds during storage were limiting factors in aseptically processing beef particulates.     

Hertzian Stress Cracks in Beryllia and Glass

The effect of Hertzian stresses resulting from loads acting at the points of contact of beryllia spheres was determined. As-drawn glass and glass ground with various grades of silicon carbide were indented with beryllia spheres, 1 in. in diameter. Also, pairs of these beryllia spheres were pressed together. Circular cracks due to Hertzian stresses were produced; an optical technique was developed for detecting them in a beryllia surface. The outer crack radius was proportional to the cube root of the maximum applied load. Average values obtained for the respective inner crack radii were used to determine average values of the minimum load to fracture these materials. The average minimum load to fracture 1 in. diameter beryllia spheres in air at room temperature under dynamic loading was 235 1b. The crack radius in glass and beryllia was about 20% greater than the radius of the contact surface. This was not significantly affected (in glass) by flaw density. It is considered that the Hertz analysis does not give the correct location and value of the maximum tensile stress when finite displacements of material occur.     

High resolution observations of Weddell Sea surface currents using ERS-l SAR sea-ice motion vectors

Two areas of the Weddell Sea, one in the south and one in the west, were chosen for a preliminary investigation of sea-ice motion tracking from ERSt Synthetic Aperture Radar (SAR) images during the Austral summer. Only a small number of images were processed, so a manual tracking method was used. In the 3–day period between SAR images the atmosphere warmed near the surface, which led to significant changes in radar backscatter from, and thus in contrast between, ice floes and the areas between them. It was therefore not always possible to track features from one image to the next. The tracked features were clearly identified in images which were sub-sampled at onesixteenth of the full resolution available. In the southern Weddell Sea images, many large floes were present which allowed a quite detailed pattern of the surface water circulation to be mapped as the ice motion was predominantly forced by the ocean currents during a period of low surface wind speeds. The observed circulation pattern agreed well with previous observations from hydrographic surveys in this area north of the Filchner Ice Shelf. In the western Weddell Sea images good tracers were hard to find, but it was still possible to detect the edge of the western boundary current of the Weddell Gyre. Continuous monitoring of sea-ice motion in these two areas using SAR imagery could be a useful means of detecting changes in surface water flow which may be linked to the rate of formation of Antarctic bottom water.     

THE USE OF BORIC OXIDE IN GLASS-MAKING

Boric oxide behaves differently from other glass-making constituents in that the variation of physical properties is not progressively continuous with a variation in composition. With increase of boric oxide content in sodium borosilicate glasses, the refractive index (μ_D) rises to a maximum as also does the annealing temperature, while the coefficient of thermal expansion reaches a minimum and then rises. The durability, or resistance to water and hydrochloric acid reaches a maximum when the glass contains about 12% of boric oxide and subsequently falls off very rapidly. There is, accordingly, a limit to the usefulness of boric oxide in glass.     

Automated tracing and volume measurements of neurons from 3-D confocal fluorescence microscopy data

Three-dimensional (3-D) image analysis algorithms and experimental results that demonstrate the feasibility of fully automated tracing of neurons from fluorescence confocal microscopy data are presented. The input to the automated analysis is a set of successive optical slices that have been acquired using a confocal scanning laser microscope. The output of the system is a labelled graph representation of the neuronal topology that is spatially aligned with the 3-D image data. A variety of topological and metric analyses can be carried out using this representation. For instance, precise measurements of volumes, lengths, diameters and tortuosities can be made over specific portions of the neuron that are specified in terms of the graph representation. The effectiveness of the method is demonstrated for a set of sample fields featuring selectively stained neurons. Additional work will be needed to refine the method for unsupervised use with complex data involving multiple intertwined neurons and extremely fine dendritic structures.     

Binding of Meat Pieces: Influence of Some Processing Factors on Binding Strength and Cooking Losses

Evacuation of the chamber of the press used to form flaked beef into a restructured meat product (patty) did not affect the binding strength of the cooked patty but under some conditions decreased the cooking loss. In studies using patty mixes containing 0–1.0% added sodium chloride, meat binding strength increased with decrease in the temperature of the mix when formed into patties over the temperature range - 1° to -5°C. The largest effect generally occurred between - 1° and -2°C. However, the effect was only noted in patties that were frozen (-30°C) before being cooked for assessment. With decrease below - 1°C of the temperature of patties when pressed, cooking losses increased for the patties without added salt but decreased for those with added salt (0.5% or 1%). Change in the pressure applied to form the patty (in the range 1.4–13.7 MPa) can affect binding strength.     

Headspace Volatiles and Sensory Characteristics of Ground Beef from Forage- and Grain-Fed Heifers

Twenty-seven yearling Hereford-Angus heifers were allotted to one of three intense managed pasture systems: Tifleaf pearl millet, sorghum sudangrass and fescue-clover. After grazing, heifers were finished in drylot and then serially slaughtered at 0, 52, and 82 days in the feedlot (DIF). A total of 51 volatiles were identified in ground beef from Longissimus dorsi (L. dorsi) muscle and subcutaneous fat. Major classes of volatile compounds identified included hydrocarbons and aldehydes plus fewer numbers of ketones, alcohols, aromatic compounds and sulfur-containing compounds. The majority of compounds which varied due to DIF were alkanals and alk-2-enals. The concentration of each of the volatiles which varied due to DIF was found to increase. None of the volatiles quantitated were positively correlated with sweetness or gamey aftertaste, the two characteristics which were highest for the O DIF cattle.