STORAGE OF RETORT POUCH BEEFSTEAK AND BEEF STEW PACKED UNDER FOUR HEADSPACE LEVELS

Changes in specific physico-chemical and sensory attributes as well as acceptability of beefsteak and beef stew Meal-Ready-to-Eat (MRE) components packed under different headspace levels (10, 20, 30 and 40 cm³) and stored at selected temperatures of 4, 27 and 38C (40, 80 and 100F) were evaluated over a six month period. No significant changes in microbial counts, pH, residual oxygen, color, hardness and oxidation occurred in retort-packed beefsteak or beef stew. Unlike beefsteak, beef stew received acceptable scores by consumers during all six months of analysis. Consumers' lack of familiarity with beefsteak may have negatively influenced product acceptability. Beefsteak and beef stew acceptability and specific attributes, particularly moistness and firmness, were detrimentally affected by high storage temperatures. Headspace may be increased to 40 cm³ without significant detrimental effects on product quality and acceptability of beefsteak or beef stew.     

Contamination of the Chalk Aquifer by Chlorinated Solvents: A Case Study of the Luton and Dunstable Area

A detailed investigation of contamination by chlorinated solvents of the Chalk Aquifer underlying the towns of Luton and Dunstable was undertaken to assess the extent, causes and mechanisms of pollution. The research programme incorporated land-use surveys, regional groundwater surveys, monitoring of groundwater abstraction points and aquifer profiling by means of the drilling of observation boreholes, the analysis of the recovered core material and the depth sampling of these and other boreholes.
Low-level solvent contamination of the Chalk Aquifer was found to be widespread with 'hotspots'of higher concentrations. At the drilling sites, both the saturated and unsaturated zones were contaminated with solvents, although free product was not observed. The presence of an additional contaminant, oil, at some sites was noted to influence the distribution of solvents within the aquifer.
Clean-up of the aquifer is not a practical option, and treatment of the groundwater at the abstraction points has been adopted.     

COMPUTER-AIDED ANALYSIS AND DESIGN OF AN ATP REGENERATION REACTOR

The two coupled reactions catalyzed by the enzymes adenylate kinase and acetate kinase for the regeneration of ATP from AMP in a CSTR were analyzed to obtain information required for the design of such a reactor. Unconventional but efficient computational methods were developed to handle the difficulty associated with the extremely complex rate expressions involved.     

Thermal Aggregation Properties of Duck Salt-Soluble Proteins at Selected pH Values

Thermal aggregation properties of duck breast and leg salt-soluble proteins (SSP) were studied at pH 5.50, 5.75 and 6.00. At pH 5.50, a major transition for breast was observed at 60.3°C and for leg at 41.8°C. At pH 5.75, major transitions at 44.6 and 43.2°C were obtained, respectively, for the breast and leg SSP. Three transitions at 46.0, 53.0 and 59.0°C were exhibited by breast SSP at pH 6.00, whereas only two major transitions at 47.4 and 54.0°C were identified in leg SSP. Changes in transition peak heights and shifts in transition temperatures as a result of pH changes indicated that, depending on fiber type, pH may enhance or suppress the aggregation behavior of specific constituents of the myosin/actomyosin complex, thereby altering the overall aggregation pattern of the protein preparation.     

Parameters Affecting Destruction of Salmonella spp. by Microwave Heating

The relationship between time of heating, temperatures achieved during heating, and consequent destruction of Salmonella spp. was examined with four microwave ovens designed for home use. Power level (output), post-heating holding time, heating medium volume, container shape, and covering of containers were investigated. Post-heating holding times of two or more minutes increased (P = 0.05) bacterial destruction, while significantly less destruction was observed in ovens of lower (e.g., 450 W) wattage. Heating medium volume, container shape, and covering containers did not significantly alter destruction of salmonellae heated to 60°.     

Phase Relations in the ZrO2-MgO System

Phase relations were studied in the system ZrO₂-MgO with emphasis on the range 1350° to 1600°C. A phase relation was determined from samples, using precision lattice parameters, X-ray diffraction line intensities, and petrographic observations, and from dynamic observations of the phases present using high-temperature X-ray diffraction techniques. Limits were established for the solubility of MgO in tetragonal ZrO₂ and for the range of the cubic solid solution. The phase relations below 1240°C were complicated by hysteresis in the monoclinic to tetragonal inversion of ZrO₂.     

Structural integrity and damage type in military aircraft

This paper discusses the nature of the damage which can cause unanticipated, early fleet failures in legacy military aircraft. This damage often takes a form quite unlike the notional cracking which is used in structural integrity design, but can lead to high costs, or reduced fleet availability, by requiring additional costly inspections and recovery programs in response to discovery of the damage. Using examples from Australian fleets the paper demonstrates that a lack of diagnostic and prognostic tools contributed to the impact of the damage on the fleet. Development of even simple prognostic and diagnostic tools could reduce the fleet impact and cost of discovered damage, and would ultimately allow the non‐crack damage to be incorporated into design to achieve a much more global level of damage tolerance. The paper discusses the key differences between these non‐crack damage forms and the more traditional crack‐like defect which is used in current damage tolerance based structural integrity management approaches for these aircraft. These differences are associated principally with damage variability and damage location, and they challenge some aspects of our existing structural integrity design methods such as reliance on testing and analysis of supposedly ‘representative’ example of aircraft structure. The larger challenge is to fully exploit the principles of damage tolerant structural design and management, and the paper argues that to achieve this we need to maintain a move towards a broader, risk‐based approach to structural integrity management. This longer‐term goal will also involve a reappraisal of the nature and distribution of damage, and a fundamental shift in our crack‐centric view of structural integrity, additional diagnostic and prognostic tools for such damage would be essential for developing this transition to a more global risk‐based damage management approach.