Beef flavor: a review from chemistry to consumer

This paper briefly reviews research that describes the sensation, generation and consumer acceptance of beef flavor. Humans sense the five basic tastes in their taste buds, and receptors in the nasal and sinus cavities sense aromas. Additionally, trigeminal senses such as metallic and astringent are sensed in the oral and nasal cavities and can have an effect on the flavor of beef. Flavors are generated from a complex interaction of tastes, tactile senses and aromas taken collectively throughout the tongue, nasal, sinus and oral cavities. Cooking beef generates compounds that contribute to these senses and result in beef flavor, and the factors that are involved in the cookery process determine the amount and type of these compounds and therefore the flavor generated. A low‐heat, slow cooking method generates primarily lipid degradation products, while high‐heat, fast cookery generates more Maillard reaction products. The science of consumer acceptance, cluster analyses and drawing relationships among all flavor determinants is a relatively new discipline in beef flavor. Consumers rate beef that has lipid degradation products generated from a low degree of doneness and Maillard flavor products from fast, hot cookery the highest in overall liking, and current research has shown that strong relationships exist between beef flavor and consumer acceptability, even more so than juiciness or tenderness. © 2015 Society of Chemical Industry     

全新安全战略--自防御网络

不久前,计算机病毒还只是一种令人不快的小问题,很少引起高层管理人员的关注。但是现在,指数级增长的安全威胁、协作式应用和互联环境让网络安全问题成为了报纸的头条新闻。这里只举一个例子:在2003年1月,SQL Slammer蠕虫导致全球各地的大量网络陷于瘫痪,甚至让韩国电信的Freet     

A combinatorial approach in designing hydrophilic surfaces for solid‐phase peptide synthesis

A hydrophilic surface suitable for solid‐state peptide synthesis was developed on a solid support called a lantern. The split‐and‐mix combinatorial technique was used to prepare about 500 surfaces in a very short time. Surfaces were analyzed according to values for gel formation, percentage weight grafted, grafted copolymer composition, and number of functional groups per lantern. These values were correlated to the purity of a peptide synthesized on these surfaces. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3371–3378, 2003     

Injection anxiety remains a long-term barrier to medication adherence in multiple sclerosis.

Objective: To evaluate the contribution of injection anxiety to disease modifying therapy (DMT) adherence among individuals with multiple sclerosis (MS). Injection anxiety has been associated with medication discontinuation early in the course of treatment, but little is known about the relationship between injection anxiety and sustained DMT adherence over time. Method: Eighty-nine outpatients receiving care at a Veterans Administration MS clinic completed a telephone survey at baseline and monthly telephone follow-up for 6 months. Results: Participants were established DMT users (M = 3.43 years, SD = 3.29), with relatively high adherence overall (over 80% achieved 80% adherence or greater). Using logistic regression and controlling for demographics, MS disability, type of DMT, and time on DMT, the authors found that baseline injection anxiety predicted lower levels of adherence at 4 months and 6 months, with a similar trend at 2 months. Conclusion: Sustained adherence to DMT remains a challenge for a subset of individuals with MS well beyond the initial period of acclimation. Injection anxiety is an important and promising target of psychological intervention during all periods of medication use. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reduction of Campylobacter jejuni on poultry by low-temperature treatment

Campylobacter jejuni is a leading cause of acute bacterial gastroenteritis in the United States, with epidemiologic studies identifying poultry as a leading vehicle in human infection. Studies were conducted to determine rates of C. jejuni inactivation on poultry exposed to different cooling and freezing temperatures. A mixture of three strains of C. jejuni originally isolated from poultry was inoculated onto chicken wings at ca. 10(7) CFU/g. The results of the study revealed that the storage of wings at -20 and -30 degrees C for 72 h reduced the population of C. jejuni on wings by 1.3 and 1.8 log10 CFU/g, respectively. The results with regard to long-term freezing for 52 weeks revealed C. jejuni reductions of ca. 4 and 0.5 log10 CFU/g on wings held at -20 and -86 degrees C, respectively. Protocols were developed to superchill wings in Whirl-Pak bags with liquid nitrogen at -80, -120, -160, and -196 degrees C such that the internal portion of each wing quickly reached -3.3 degrees C but did not freeze. The results with regard to the superchilling of wings at different temperatures for 20 to 330 s (the time required for the wings to reach an internal temperature of -3.3 degrees C) revealed C. jejuni reductions of 0.5 log10 CFU/g for wings held at -80 degrees C, 0.8 log10 CFU/g for wings held at -120 degrees C, 0.6 log10 CFU/g for wings held at -160 degrees C, and 2.4 log10 CFU/g for wings held at -196 degrees C. The superchilling of wings to quickly cool meat to -3.3 degrees C (internal temperature) can substantially reduce C. jejuni populations at -196 degrees C when the wings are submerged in liquid nitrogen, but not at -80 to -160 degrees C when the wings are treated with vapor-state liquid nitrogen. The results of this study indicate that freezing conditions, including temperature and holding time, greatly influence the rate of inactivation of C. jejuni on poultry. The conditions used in the poultry industry to superchill poultry to a nonfrozen-state internal temperature are not likely to substantially reduce Campylobacter populations on fresh products.     

Neutron irradiation of sapphire for compressive strengthening.: I. Processing conditions and compressive strength

Sapphire suffers a dramatic loss of c-axis compression strength at elevated temperatures. Irradiation of sapphire with fission-spectrum neutrons to an exposure of ∼10²² neutrons/m² in the core of a 1 MW fission reactor increased the c-axis compression strength by a factor of ∼3 at 600 °C. Strength was similarly improved when 99% of slow neutrons (?0.1 eV) were removed by 10B and Cd shields during irradiation. Annealing at 600 °C for 10 min changed the yellow-brown color of irradiated sapphire to pale yellow, but had no effect on compressive strength. Annealing irradiated sapphire at 1200 °C for 24 h reduced the compressive strength to its baseline value. Transmission electron microscopy suggests that fast-neutron-induced displacement damage inhibits the propagation of r-plane twins which are responsible for the low compressive strength. When irradiated with 10B and Cd shielding, sapphire that was not grown in iridium crucibles is safe for unrestricted handling after 1 month.     

Social comparison and dissonance reduction in self-evaluation.

This study is designed to compare and test some predictions about the self-evaluation process based on the theories of Festinger and Rotter. Contrary to suggestions by Rotter, it was found that minimal goals were no more resistant to change than were expected scores. Changes in minimal goals and expected scores tended to occur so as to minimize discrepancies with actual performance, and thus reduce dissonance in accordance with Festinger's theory. Consistent with Festinger's theory of social comparison processes, it was found that individual's self-evaluations are only influenced by reference group norms in the absence of a more objective criterion for self-evaluation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Construct validity of the multidimensional structure of bullying and victimization: An application of exploratory structural equation modeling.

Existing research posits multiple dimensions of bullying and victimization but has not identified well-differentiated facets of these constructs that meet standards of good measurement: goodness of fit, measurement invariance, lack of differential item functioning, and well-differentiated factors that are not so highly correlated as to detract from their discriminant validity and substantive usefulness in school settings. Here we demonstrate exploratory structural equation modeling, an integration of confirmatory factor analysis and exploratory factor analysis. On the basis of responses to the 6-factor Adolescent Peer Relations Instrument (verbal, social, physical facets of bullying and victimization), we tested invariance of factor loadings, factor variances–covariances, item uniquenesses, item intercepts (a lack of differential item functioning), and latent means across gender, year in school, and time. Using a combination of relations with student characteristics and a multitrait–multimethod analysis, we showed that the 6 bully/victim factors have discriminant validity over time and in relation to gender, year in school, and relevant psychosocial correlates (e.g., depression, 11 components of academic and nonacademic self-concept, locus of control, attitudes toward bullies and victims). However, bullies and victims are similar in many ways, and longitudinal panel models of the positive correlations between bully and victim factors suggest reciprocal effects such that each is a cause and an effect of the other. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Assessment of off-flavor development in restructured chicken nuggets using hexanal and TBARS measurements and sensory evaluation

The hexanal contents of chicken nuggets treated with various anti-oxidants were evaluated in relation to the development of warmed-over flavor (WOF) during frozen storage. Of the antioxidant treatments tested, the sodium tripolyphosphate (STPP)/tertiary butylhydroquinone combination showed the greatest effect by decreasing hexanal production by 95%. Combinations of STPP/oleoresin rosemary, (0.5 g kg^?1 and 1 g kg^?1) decreased the hexanal contents by 85% and 91%, respectively. A higher correlation coefficient (pooled, within treatments) between hexanal contents and sensory scores for WOF (r = 0.68) relative to that between hexanal contents and thiobarbituric acid reactive substances values (r = 0.14) was obtained. A pooled, correlation coefficient within treatments and storage times (r = 0.56), was found between TBARS and sensory scores. It was concluded that the use of correlation coefficients calculated without pooling groups of data within each significant experimental factor to interrelate the results of different analyses may be inappropriate.     

Performance analysis and impedance spectral signatures of high temperature PBI–phosphoric acid gel membrane fuel cells

Polarization curves, i.e., dc performance, and impedance spectral signatures of polybenzimidazole (PBI)–phosphoric acid (H₃PO₄) membrane fuel cells are obtained in the temperature range of 160–180 °C, in an effort to investigate the effect of temperature, anode humidification, various cathode stoichs, and use of oxygen versus air. Thus, in situ electrochemical impedance spectroscopy (EIS) was used to obtain various resistances, ohmic as well as charge-transfer resistances, under these conditions. The results obtained show that PBI–H₃PO₄ gel membrane fuel cells exhibit very good performance in the temperature range of 160–180 °C with an ohmic resistance similar to Nafion. Mass transfer limitations were determined by comparing performance polarization curves with air and oxygen along with EIS. Further EIS was also used to obtain signatures during fuel starvation, and electrical shorting across the cell.