Effect of preservatives addition on the shelf-life extensions and quality of flat bread as determined by near-infrared spectroscopy and texture analysis

Many people do not have refrigeration or frozen storage to inhibit mould growth and keep the Arabic bread fresh for more than a few days. Therefore, shelf-life extension is necessary for this type of bread. The present study hypothesised that the addition of preservatives may be done in Arabic flat bread (AFB) to extend shelf-life. Thus, objectives of this study were to evaluate selected preservatives to inhibit mould growth and to employ physical techniques, to monitor bread aging. Three preservatives, fumaric acid (0.2%, F), sodium propionate (0.3%, P), and sodium propionate-fumaric acid mixture (PF) were used. Tensile tests, and near-infrared reflectance spectroscopy (NIRS) were used to monitor bread ageing. The addition of PF in the AFB formula significantly increased the time of tearing at 0 day. For all treatments, the NIRS results showed high R²-values between the actual storage days and NIRS predictions. The NIRS and texture analysis are valuable tools to detect the effect of the preservatives on AFB shelf-life and quality.     

Priority discarding of speech in integrated packet networks

The authors discuss the control of short-term congestion, which is referred to as overload, in integrated packet networks (IPNs) containing a mix of data, speech, and possibly other types of signals. A system model is proposed that assigns a delivery priority to each packet (speech or otherwise) at the transmitter and discards speech packets according to delivery priority at any point in the network in response to overload. This model attempts to minimize per-packet processing at networks nodes. The research described is guided by two principles for IPN design: minimal per-packet processing and flexibility due to signal structure. The quality of the received speech is maintained by classifying speech segments according to their structure and coding them in a way that ensures ease of lost-packet regeneration at the receiver. The results of an experiment are reported that confirmed the general validity of this model from the standpoint of transmitter and receiver processing and subjective quality     

Inlet plenum pressure drop calculation for a cross-flow module

Outlined here is a method for applying a model of discharge flow through a series of sharp-edged orifices from an inlet plenum, to accurately predict the total pressure drop across the flow distribution geometry. This particular case relates to a cross-flow filtration membrane module, but is applicable for any flow distribution system of a similar format.     

Mechanisms of crack nucleation in ice

This paper reviews the literature on the mechanisms by which cracks are nucleated in polycrystalline ice. In the absence of preexisting cracks, crack nucleation is the first step in mechanical failure. A variety of mechanisms have been discussed, mostly involving the propagation of microcracks or precursors from initial sizes below the level of convenient detection to easily observable cracks. True crack nucleation without preexisting precursors requires that stresses be locally concentrated to levels matching the theoretical cleavage or cohesive strength. Candidate mechanisms for this concentration of stress include: dislocation glide (leading to pile-ups of dislocations on particular slip planes); grain-boundary-sliding (leading to stress concentrations at the triple junctions at the edge of grain-boundary facets); thermal expansion of extraneous inclusions (such as produced by progressive freezing of brine pockets upon cooling); and elastic anisotropy of the ice crystals. Both dislocation glide and boundary sliding are kinetic processes in which the stress redistribution occurs at a finite, temperature-dependent rate. These processes also contribute temperature-dependent internal friction and anelasticity and their operation can therefore be independently measured. Elastic anisotropy leads to stress concentrations in an athermal manner and therefore becomes more important at very low temperatures and high loading rates. It has been shown, however, that in the absence of stresses due to brine pockets, the inherent elastic anisotropy of ice is not sufficient to nucleate cracks in purely two-dimensional models, such as perfectly columnar grains in plane strain. Calculated nucleation energies are far beyond available thermal activation energies and some additional stress concentrating effects are required. Irregularities in the third dimension (e.g. jogs in column boundaries) have not been completely investigated. Although inclusions (e.g. brine pockets or particulate inclusions) may sometimes be important, we should not neglect the kinetic processes mentioned above. Various experiments on fresh-water ice have provided evidence that crack nucleation is usually associated with grain boundaries in a manner consistent with grain-boundary sliding and the associated stress concentration fields.     

The effects of defects on the early failure of metal interconnects

A method that predicts the effect of particular defects on the failure rate of metal interconnections in semiconductor integrated circuits due to electromigration is presented. The defects of interest are missing material that reduces the effective cross section of the conductor at the point of the defect. Reliability measures for the conductor are computed from a given defect distribution. These defects appreciably increase conductor failure rate during early life but have little effect on median life for linewidths above 1 μm. However, for defect densities typically encountered in current semiconductor manufacturing environments a rapid decrease in median life is predicted for conductors less than 0.30 μm wide. This result extends the practical data for submicron conductors. Poorer median life as well as poorer yield due to these defects will ultimately limit the trend toward narrower linewidths unless a way is found to overcome this problem     

Evaluation of the conduction shape factor with a CFD code for a liquid–metal heat transfer in heated triangular rod bundles

A heat transfer due to conduction through a coolant itself is not negligible in a liquid–metal cooled reactor (LMR). This portion of a heat transfer is frequently described with a conduction shape factor during the thermal-hydraulic design of an LMR. The conduction shape factor, which is highly dependent on a pitch-to-diameter (P/D) ratio, is defined as the ratio of the local conduction heat flux at a gap between two subchannels to the reference heat flux calculated by the averaged subchannel temperatures. The shape factors in heated triangular rod arrays for three different pitch-to-diameter ratios are generated through CFX calculations in the present study. The flow paths of 1.0–2.0 m in length are meshed into 180,000–360,000 volumes depending on the flow velocities. The SSG Reynolds stress model is used as a turbulent model in the calculations. The evaluated data fell between the heated-rod data and the plane-source data obtained by theoretical investigations. The conduction shape factors were found to be independent of the heating pattern of the rod arrays. Based on the evaluated data, a correlation for a liquid sodium coolant is suggested, which will improve the accuracy of the subchannel analysis codes for the thermal-hydraulic design of an LMR. When it is compared with the existing correlations, the suggested correlation is expected to enhance the reliability of the conduction shape factor because the data is evaluated by a more realistic numerical experiment.     

Prevalence and numbers of Salmonella and Campylobacter spp. on raw,whole chickens in relation to sampling methods

Salmonella and Campylobacter continue to be major foodborne pathogens and raw poultry is considered to be an important source of these bacteria. In this study, the prevalence and numbers of Salmonella and Campylobacter spp. in relation to isolation/sampling methods were determined in 241 whole raw chickens purchased from retail outlets in England during the winters of 1998/1999 (101 chickens) and 1999/2000 (140 chickens). The packaging of the 140 chickens was also examined for the presence of the above pathogens. The prevalence and numbers of enterococci were examined in 21 of the 101 chickens. In total, Salmonella and Campylobacter spp. were present in 25% and 83% of the chickens, respectively. Salmonella were isolated from a sample representing both the inside and outside of the packaging in 19% of the chickens, while the corresponding figure for Campylobacter spp. was 56%. Both of these pathogens were isolated from the outside of the packaging in 6% of the chickens. Salmonella was more frequently isolated from samples containing chicken skin in comparison with those containing carcass-rinse fluid only. Two chickens (0.8%) were positive for Salmonella by direct enumeration methods with contamination levels of log10 3.8 and 4.5 colony forming units (cfu) per carcass, respectively. The most prevalent serotypes were S. Hadar, S. Enteritidis and S. Indiana and two different serotypes were identified in 5/20 salmonella-positive chickens. Resistance to at least one antibiotic was found in 70% of the strains, 46% were multiresistant (resistant to > or = four drugs) and 52% showed a lowered susceptibility to ciprofloxacin. The likelihood of isolating Campylobacter spp. from neck-skin, carcass-rinse or carcass-rinse plus whole skin samples was similar, Campylobacter spp. were found in higher levels in carcass-rinse or carcass-rinse plus whole skin samples than in neck-skin. The log10 cfu of Campylobacter spp. were 2.70-4.99 in 18% of the chickens and 5.00-6.99 in 20%. Campylobacter isolates (425) comprised Campylobacter jejuni (98%) and C. coli (2%) and 98 different sero/phagetypes of these two species were identified. Resistance to at least one antibiotic was found in 73% of the strains and 13% were multiresistant. Thirteen percent of the strains showed lowered susceptibility to ciprofloxacin, while 4.9% were resistant to erythromycin. Vancomycin-resistant enterococci (VRE), able to grow on agar containing 15 mg l(-1) vancomycin (VRE15), were present in 19 chickens. The log10 cfu of VRE15 was 2.90-3.99 in 10 chickens and between 4.00 and 4.99 in two chickens. The data presented here contribute to risk assessment and highlight the need to continue to emphasise the safe handling of raw retail poultry.     

Aging and Enhancement Effects on Quality Characteristics of Beef Strip Steaks

ABSTRACT: Strip loins were removed 48 h postmortem from beef sides ( n = 20 pairs) to assess the effects of enhancement before or after aging on quality attributes of beef strip steaks. Strip loins were enhanced to 108% of original weight to contain 0.4% alkaline phosphate, 0.3% salt, 0.1% natural flavoring (on a final weight basis), and added water for comparison with non-enhanced samples. Regardless of when enhancement occurred relative to aging, enhanced samples were more tender, juicy, and salty than their non-enhanced counterparts. Enhanced samples were lighter, less red and less yellow, and had lower L *, a *, and b * values than non-enhanced samples; however, they generally had lower hue angles indicating that their color was closer to the true red axis of the color scale. Samples enhanced before aging achieved maximum tenderness after 14 d, whereas those enhanced after aging experienced no tenderness changes. Warner- Bratzler shear values were lower and pH values were higher in enhanced steaks than in controls.     

Does familiarity breed contempt or liking? Comment on Reis, Maniaci, Caprariello, Eastwick, and Finkel (2011).

Reis, Maniaci, Caprariello, Eastwick, and Finkel (see record 2011-04644-001) conducted 2 studies that demonstrate that in certain cases, familiarity can lead to liking—in seeming contrast to the results of our earlier article (see record 2006-23056-008). We believe that Reis et al. (a) utilized paradigms far removed from spontaneous, everyday social interactions that were particularly likely to demonstrate a positive link between familiarity and liking and (b) failed to include and incorporate other sources of data—both academic and real-world—showing that familiarity breeds contempt. We call for further research exploring when and why familiarity is likely to lead to contempt or liking, and we suggest several factors that are likely to inform this debate. (PsycINFO Database Record (c) 2011 APA, all rights reserved)