Effect of pre-treatment with carbon monoxide and film properties on the quality of vacuum packaging of beef chops

Beef chops (longissimus dorsi) were pre-treated with 5% carbon monoxide (CO) − 95% N₂ for 24 h, vacuum packed in thermo-contractile bags and stored at 0 ± 2°C. Shelf life, as determined by the viable aerobic bacterial load, was 11 weeks. Vacuum-packed chops with heat-contractile film produced a smaller drip loss, had a more intense red colour and higher colour stability under storage than chops with non-heat-contractile film. Chops pre-treated with CO were redder during all the storage period than controls without CO. The pre-treatment did not affect pH, water-holding capacity, drip loss or rancidity of the meat stored in vacuum. Copyright © 2008 John Wiley & Sons, Ltd.     

Qualitative and quantitative analyses of volatiles and pheromone gland extracts collected fromGalleria mellonella (L.) (Lepidoptera: Pyralidae)

Chemical analyses of pheromone-gland extracts and volatiles released by maleGalleria mellonella (L.), the greater wax moth, resulted in the identification and quantification of the aldehydes, primary alcohols, and fatty acids of nonane and undecane. Adult females released none of these six compounds. Mean percentages of the aldehydes and alcohols in the gland extracts were 19.0% undecanal, 3.9% nonanal, 48.3% 1-undecanol, and 28.8% 1-nonanol. Mean percentages of the aldehydes and alcohols in volatiles collected during the first hour of scotophase from moths 1 to 9 days old were 77.4% undecanal, 20.8% nonanal, 1.46% 1-undecanol, and 0.36% 1-nonanol. Age did not significantly affect the amount of each compound collected. The collection of volatiles from moths 3 to 5 days old during a 12-hr scotophase indicated that production was greatest during the first and third quarters of the period. Methylation of group volatile samples allowed the quantification of the fatty acids.     

Accelerated inactivation of Geobacillus stearothermophilus spores by ohmic heating

Until recently, ohmic heating was commonly thought to kill microorganisms through a thermal effect. However a growing body of evidence suggests that non-thermal effects may occur. Our aim was to determine the kinetics of inactivation of Geobacillus stearothermophilus spores (ATCC 7953) under ohmic and conventional heating using a specially constructed test chamber with capillary sized cells to eliminate potential sources of error and ensure that identical thermal histories were experienced both by conventionally and ohmically heated samples. Ohmic treatments at frequencies of 60 Hz and 10 kHz were compared with conventional heating at 121, 125 and 130 °C for four different holding times. Both ohmic treatments showed a general trend of accelerated spore inactivation. It is hypothesized that vibration of polar dipicolinic acid molecules (DPA) and spore proteins to electric fields at high temperature conditions may result in the accelerated inactivation.     

Effect of the types and concentrations of alkali on the color of cocoa liquor

BACKGROUND: The alkalization process is extensively used in the cocoa industry, but information is scarce and not easy to acquire. The goal of the study was to evaluate the effect of different types and concentrations of alkali on the color of cocoa liquor. Dried beans from Chuao (state Aragua, Venezuela) were used to produce cocoa liquors. Samples of liquors were alkalized with solutions of NaHCO₃, Na₂CO₃ and NaOH at concentrations of 10, 20 and 30 g kg^?1. RESULTS: The data showed that values of the coordinates L*, a* and b* decrease when liquors were treated with the three different types and concentrations of alkalis. Almost all samples had ΔE* values above 1. The ratios b*/a* and a*/b* and the proximate composition were also modified. Crude protein, crude fat and polyphenol concentrations were decreased and the ash content augmented as concentrations of the alkalis were increased. The fatty acid and sugar profiles were also affected. These ratios were most pronounced when NaOH was used. CONCLUSION: The selection of the type or concentration of alkali is a function of the type of product to be elaborated. Copyright © 2009 Society of Chemical Industry     

COMPACT BACKSCATTER FIBER OPTIC SYstems FOR SUBMICROSCOPIC PARTICLE SIZING

A compact backscatter fiber optic system, comprising a semiconductor laser diode, a fiber optic probe and a self-contained photomultiplier, is described. Backscatter fiber optic probes provide easy access over a range of scattering angles between 95 and 175 degrees. Accuracy of the portable dynamic light scattering system is assessed through measurements made on a 39 nm polystyrene latex spheres suspension.     

A kinetic study of the thermal degradation of chitosan‐metal complexes

The thermal degradation of metal complexes formed by chitosan with Cu(II), Ni(II), Co(II), and Hg(II), at different metal concentrations, was studied by thermogravimetric analysis in a nitrogen atmosphere over the temperature range 25–800°C. The results indicate that thermal degradation of chitosan and chitosan‐metal ion complexes could be of one or two‐stage reaction. In the thermal degradation of chitosan with metal complexes, the temperature of initial weight loss and the temperature of maximum weight loss rate decrease. Fourier transform infrared spectroscopy was used to probe the interaction of chitosan with metal ions. The bands of ? N? H, ? C?O, ? C? O? C? groups of chitosan are shifted or change their intensity in the presence of metal. These changes in the characteristic bands are taken as evidence of the influence of metal ions on the thermal stability of chitosan. Broido's method was employed to evaluate the activation energies as a function of the degree of degradation. The presence of metal ions provoked a decrease in the thermal stability of chitosan, which became more marked when the concentration of metal was increased. The dynamic study showed that the apparent activation energy values of the main stage of the thermal degradation of chitosan‐metal complexes decrease as the strength of the polymer‐metal interaction increases. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Ohmic sterilization inside a multi-layered laminate pouch for long-duration space missions

A pouch that can be used to ohmically reheat and sterilize food and later reused to stabilize waste will significantly reduce the Equivalent System Mass during a long term space mission. Reheating of food and stabilization of waste have been successfully done in the past using a V-shaped electrode pouch using pulsed ohmic heating, however improvement of field distribution was needed. The main goals of this work were to develop an improved pouch design to facilitate uniform ohmic heating of food; to model ohmic sterilization within the pouch; and to verify the model through an inoculated pack study.     

A lifecycle-based success framework for grid-connected biomass energy projects

This paper presents a new framework to help assessing the success and its drivers of biomass energy projects. Empirical validation of the framework using data collected from operating grid-connected biomass energy plants in Thailand indicates that competencies of developer and project team members in designing biomass energy plants and conducting environment impact assessment (EIA) are significant factors for the success of the project development phase. In the construction phase, effective coordination, consultation and communication among the project team and the contractors emerge as the most significant success factors, while a competent management and O&M team is found critical to success during the operation phase. External factors such as the presence of supportive legislative, political and regulatory framework are found most instrumental for achieving overall project success. The framework demonstrates the dynamic linkage of project management success in successive lifecycle stages and phases, and thus can be used to evaluate and forecast the likelihood of success of biomass energy projects progressively over their lifecycle.