Fatigue perturbed creep of pure aluminum at ambient temperatures

The creep of 99.999 pct pure aluminum subject to tension-tension cyclic stressing (dynamic creep) has been studied and compared to creep for the peak cyclic stress applied statically (static creep). The creep rate for a cyclic stress of 29.8 to 3.7 MPa was always found to be greater than the creep rate for static application of a stress of 29.8 MPa over the temperature range of 302 K to 348 K. The ratio of the dynamic creep rate to the static creep rate was found to increase with increasing strain and decreasing temperature. The apparent activation energy measured for dynamic creep was less than that measured for static creep. The substructure for dynamic creep is softer than for static creep and probably accounts for the accelerated creep rate and the lower observed activation energy.     

Fat-simulating and accelerating solvents for polyolefins and MWD of solvent extracts of polyethylenes

Migration kinetics of straight-chain oligomers and antioxidants from several polyolefins at different temperatures into various solvents have been studied by radioactive tracer techniques. Anhydrous ethanol appears to be a well suited food-oil or liquid-fat simulant for extracting different types of migrants from polyolefins. Pure and mixed triglycerides are also good oil or fat simulants, but the triglycerides offer no simpler analytical procedures than the use of oil or fat themselves. n-Octanol may also be considered as a reasonable oil or fat simulant; however, its action depends somewhat on the choice of migrants. The accelerating action of n-heptane over that of oil or simulants is quantitatively demonstrated. The accelerating effects are greater for migration systems with lower diffusion coefficients. The diffusion coefficients for migration into n-heptane are about 20 times greater than the diffusion coefficients into ethanol or oil for otherwise identical migration systems yielding diffusion coefficients of about 10^?7 cm²s^?1 into oil or ethanol. For systems yielding diffusion coefficients into oil or ethanol of about 10^?12 cm²s^?1, the corresponding diffusion coefficients into n-heptane are about 1000 times greater. The molecular weight distributions (MWDs) of the n-heptane and ethanol extracts of polyolefins have been analysed. n-Heptane can not only accelerate the migration of the individual migrant but also remove oligomer species that are slightly soluble or present at low levels in the oil or simulant extracts.     

Bestimmung niedermolekular gebundener Purin- und Pyrimidinbasen in Lebensmitteln nach gelchromatographischer Isolierung und hydrolytischem Druckaufschlu?

Zusammenfassung Die gelchromatographisch abgetrennten und isolierten niedermolekularen Purin- und Pyrimidinverbindungen wurden nach hydrolytischem Druckaufschluß an einem Kationenaustauscher als freie Basen bestimmt. Diese Daten werden auch im Verhältnis zu den Gesamtgehalten der Basen des Substrates mitgeteilt. Es zeigte sich, daß bei unbehandelten Proben der Anteil der niedermolekular gebundenen Basen 5–15% (je nach Base und Lebensmittel) der jeweiligen Gesamtbasenmenge beträgt. Bei frischen, nicht erhitzten Lebensmittelproben findet ein schneller Abbau von Adeninnucleotiden zu Inosinnucleotiden und zu Hypoxanthin statt, so daß nur geringe Adeningehalte aus niedermolekularen Verbindungen angetroffen werden. Bei erhitzten Lebensmitteln ist der Anteil niedermolekular gebundener Purin- und Pyrimidinbasen durch Teilhydrolyse von Nucleinsüren höher. Er beträgt dann 30–50% (je nach Base und Lebensmittel) der jeweiligen Gesamtbasenmenge.

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Determination of purine and pyrimidine bases, bound in compounds of low-molecular weight after isolation by gelpermeation-chromatography and hydrolytic digestion under pressure

Summary Compounds with purine and pyrimidine bases of low-molecular weight were separated and isolated by gelpermeation-chromatography. After acid hydrolysis of nucleotides to free bases in a pressure digestion vessel the bases were separated on cation exchange resins. The data obtained are also reported in relation to the total base content of the substrate. It could be demonstrated that in untreated samples the portion of combined bases of low-molecular weight results in 5 to 15% of the corresponding total base content, depending on base and kind of food. In fresh unheated food samples adenine nucleotides are con verted rapidly to inosine nucleotides and hypoxanthine; therefore only a small share of adenine is found from compounds of low-molecular weight. In heated food the portion of combined low-molecular weight purine and pyrimidine bases proves to be much higher, due to partial hydrolysis of nucleic acids. It amounts to 30 to 50% of the total base content, depending on base and kind of food.

     

Facing the issues.

Replies to P. L. Wachtel (see PA, Vol. 51:Issue 5) stating that efforts to achieve integration between psychodynamic and behavioral approaches are appealing, but are unlikely to succeed unless the empirical issues are faced without distortion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Resistant starch—An accessible fiber ingredient acceptable to the Western palate

Dietary fiber intakes in Western societies are concerningly low and do not reflect global recommended dietary fiber intakes for chronic disease prevention. Resistant starch (RS) is a fermentable dietary fiber that has attracted research interest. As an isolated ingredient, its fine particle size, relatively bland flavor, and white appearance may offer an appealing fiber source to the Western palate, accustomed to highly refined, processed grains. This review aims to provide a comprehensive insight into the current knowledge (classification, production methods, and characterization methods), health benefits, applications, and acceptability of RS. It further discusses the present market for commercially available RS ingredients and products containing ingredients high in RS. The literature currently highlights beneficial effects for dietary RS supplementation with respect to glucose metabolism, satiety, blood lipid profiles, and colonic health. An exploration of the market for commercial RS ingredients indicates a diverse range of products (from isolated RS2, RS3, and RS4) with numerous potential applications as partial or whole substitutes for traditional flour sources. They may increase the nutritional profile of a food product (e.g., by increasing the fiber content and lowering energy values) without significantly compromising its sensory and functional properties. Incorporating RS ingredients into staple food products (such as bread, pasta, and sweet baked goods) may thus offer an array of nutritional benefits to the consumer and a highly accessible functional ingredient to be greater exploited by the food industry.     

Antibiofilm activity of the essential oil of citronella (Cymbopogon nardus) and its major component,geraniol, on the bacterial biofilms of Staphylococcus aureus

Food Science and Biotechnology - Medicinal plants with antimicrobial action have been investigated for uses against biofilms, among which, Cymbopogon nardus, citronella, stands out as a promising...     

Effect of moisture on salmonella spp. heat resistance in cocoa and hazelnut shells

The heat resistance of food-poisoning outbreak and non-outbreak associated strains of Salmonella (S. Enteritidis, S. Montevideo, S. Napoli, S. Oranienburg, S. Poona, S. Senftenberg and S. Typhimurium) was established in confectionery-related materials such as crushed cocoa bean and hazelnut shells at low moisture contents (≤ 4% w/w). The two most heat resistant strains in cocoa and hazelnut shells at ca. 4% w/w moisture were S. Oranienburg and S. Enteritidis PT30. Both strains were associated with outbreaks from dried materials. Their D_100°C values were ca. 2.5 min in crushed cocoa bean shells and 7–11 min in crushed hazelnut shells. Addition of moisture to ca. 7% w/w markedly reduced D-values (D_80°C of 2–4.5 min) for both strains in the two matrices.     

Evaluation of ability of ferulic acid to control growth and fumonisin production of Fusarium verticillioides and Fusarium proliferatum on maize based media

The aim of this study was to evaluate the efficacy of ferulic acid (1, 10, 20 and 25 mM) at different water activity (a_w) values (0.99, 0.98, 0.96 and 0.93) at 25 °C on growth and fumonisin production by Fusarium verticillioides and Fusarium proliferatum on maize based media. For both Fusarium species, the lag phase significantly decreased (p ≤ 0.001), and the growth rates increased (p ≤ 0.001) at the lowest ferulic acid concentration used (1 mM), regardless of the a_w. However, high doses of ferulic acid (10 to 25 mM) significantly reduced (p ≤ 0.001) the growth rate of both Fusarium species, regardless of the a_w. In general, growth rate inhibition increased as ferulic acid doses increased and as media a_w decreased. Fumonisin production profiles of both Fusarium species showed that low ferulic acid concentrations (1–10 mM) significantly increased (p ≤ 0.001) toxin production, regardless of the a_w. High doses of ferulic acid (20–25 mM) reduced fumonisin production, in comparison with the controls, by both Fusarium species but they were not statistically significant in most cases. The results show that the use of ferulic acid as a post-harvest strategy to reduce mycotoxin accumulation on maize needs to be discussed.