Shelf stability and sensory properties of flour tortillas fortified with pinto bean (Phaseolus vulgaris L.) flour: Effects of hydrocolloid addition

To flour tortillas formulations containing 25 g/100 g of pinto bean flour, 0.5 g/100 g and 0.75 g/100 g of guar gum and sodium carboxymethyl cellulose (CMC) were added and their shelf stability was studied at 4 and 25 °C over 7 days. Texture, determined instrumentally, rollability, and water holding capacity were the main parameters studied. Selected samples were evaluated by 55 participants to determine consumer acceptability. Firmness and cohesiveness were negatively affected by the addition of bean flour, however, this effect was partially overcome by the addition of hydrocolloids. Guar gum had a positive significant influence on water holding capacity and texture over time (P < 0.001), while CMC had no positive effects. Despite the instrumental texture data, which showed that bean tortillas had inferior attributes than the wheat control, consumers found the overall texture and acceptability of bean tortillas with and without guar gum on the range of “like very much” and “like moderately”, which was significantly higher than the wheat control (P < 0.01). Based on physical and sensorial properties it would appear that these foods are industrially feasible and highly acceptable by health-conscious consumers.     

Iron isotope fractionation during proton-promoted, ligand-controlled, and reductive dissolution of Goethite

Iron isotope fractionation during dissolution of goethite (alpha-FeOOH) was studied in laboratory batch experiments. Proton-promoted (HCl), ligand-controlled (oxalate dark), and reductive (oxalate light) dissolution mechanisms were compared in order to understand the behavior of iron isotopes during natural weathering reactions. Multicollector ICP-MS was used to measure iron isotope ratios of dissolved iron in solution. The influence of kinetic and equilibrium isotope fractionation during different time scales of dissolution was investigated. Proton-promoted dissolution did not cause iron isotope fractionation, concurrently demonstrating the isotopic homogeneity of the goethite substrate. In contrast, both ligand-controlled and reductive dissolution of goethite resulted in significant iron isotope fractionation. The kinetic isotope effect, which caused an enrichment of light isotopes in the early dissolved fractions, was modeled with an enrichment factor for the 57Fe/ 54Fe ratio of -2.6 per thousandth between reactive surface sites and solution. Later dissolved fractions of the ligand-controlled experiments exhibit a reverse trend with a depletion of light isotopes of approximately 0.5 per thousandth in solution. We interpret this as an equilibrium isotope effect between Fe(III)-oxalate complexes in solution and the goethite surface. In conclusion, different dissolution mechanisms cause diverse iron isotope fractionation effects and likely influence the iron isotope signature of natural soil and weathering environments.     

Effects of Fermentation Parameters and Cell Wall Properties on Yeast Flocculation1

Industrial wort was fermented with a NewFlo phenotype ale yeast in lab‐scale cylindrical fermenters. The effects of various fermentation parameters and yeast cell wall properties on yeast flocculation were studied during 120 h fermentation. The evaluation of the cell volume during the fermentation revealed a non‐normal distribution (p < 0.05) at most fermentation times. Overall yeast cell size initially decreased during the first 24 h of fermentation then increased during the 24–60 h fermentation period. Cell size subsequently declined until the end of fermentation presumably due to floc settling. While yeast flocculation began after 24 h fermentation, most flocs remained in suspension until 60 h when the average turbulent shear rate caused by CO₂ evolution declined to below 8 s^?1. Both the Helm's flocculence and cell surface hydrophobicity values rapidly increased to high numbers from 24 h onward. Changes in the orthokinetic capture coefficient (α₀) value with fermentation time, measured in fermenting worts, indicated a significant increase (p < 0.001) after 24 h of fermentation. Presumably, this change was due to increases in ethanol and the decline in sugar concentration with time. Although a significant positive correlation (p < 0.05) was observed between zymolectin densities and cell surface areas, the total zymolectin level on yeast cell walls did not change significantly with fermentation time (p > 0.05). Interestingly, no significant difference existed in Helm's flocculation values of suspended and settled yeast cells (p > 0.05). The flocculation rate of LCC125 was readily inhibited by addition of glucose or maltose. Results suggest that fermentable sugar levels and shear force exert major influences on yeast flocculation during beer fermentations.     

The Less We Eat,the Longer We Live: Can Caloric Restriction Help Us Become Centenarians?

Striving for longevity is neither a recent human desire nor a novel scientific field. The first article on this topic was published in 1838, when the average human life expectancy was approximately 40 years. Although nowadays people on average live almost as twice as long, we still (and perhaps more than ever) look for new ways to extend our lifespan. During this seemingly endless journey of discovering efficient methods to prolong life, humans were enthusiastic regarding several approaches, one of which is caloric restriction (CR). Where does CR, initially considered universally beneficial for extending both lifespan and health span, stand today? Does a lifelong decrease in food consumption represent one of the secrets of centenarians’ long and healthy life? Do we still believe that if we eat less, we will live longer? This review aims to summarize the current literature on CR as a potential life-prolonging intervention in humans and discusses metabolic pathways that underlie this effect.     

Microstructural,Optical and Magnetic Study of Ni–Zn Nanoferrites

Journal of Superconductivity and Novel Magnetism - NixZn1-xFe2O4 (x?=?0.0, 0.2, 0.4, 0.5, 0.6, 0.8 and 1.0) nanoferrites were synthesized using the citrate precursor method with...     

Life cycle greenhouse gas emissions of current oil sands technologies: GHOST model development and illustrative application

A life cycle-based model, GHOST (GreenHouse gas emissions of current Oil Sands Technologies), which quantifies emissions associated with production of diluted bitumen and synthetic crude oil (SCO) is developed. GHOST has the potential to analyze a large set of process configurations, is based on confidential oil sands project operating data, and reports ranges of resulting emissions, improvements over prior studies, which primarily included a limited set of indirect activities, utilized theoretical design data, and reported point estimates. GHOST is demonstrated through application to a major oil sands process, steam-assisted gravity drainage (SAGD). The variability in potential performance of SAGD technologies results in wide ranges of "well-to-refinery entrance gate" emissions (comprising direct and indirect emissions): 18-41 g CO(2)eq/MJ SCO, 9-18 g CO(2)eq/MJ dilbit, and 13-24 g CO(2)eq/MJ synbit. The primary contributor to SAGD's emissions is the combustion of natural gas to produce process steam, making a project's steam-to-oil ratio the most critical parameter in determining GHG performance. The demonstration (a) illustrates that a broad range of technology options, operating conditions, and resulting emissions exist among current oil sands operations, even when considering a single extraction technology, and (b) provides guidance about the feasibility of lowering SAGD project emissions.     

Using biological motion to enhance the conspicuity of roadway workers

This study examined whether the conspicuity of road workers at night can be enhanced by distributing retroreflective strips across the body to present a pattern of biological motion (biomotion). Twenty visually normal drivers (mean age = 40.3 years) participated in an experiment conducted at two open-road work sites (one suburban and one freeway) at night-time. At each site, four road workers walked in place wearing a standard road worker night vest either (a) alone, (b) with additional retroreflective strips on thighs, (c) with additional retroreflective strips on ankles and knees, or (d) with additional retroreflective strips on eight moveable joints (full biomotion). Participants, seated in stationary vehicles at three different distances (80 m, 160 m, 240 m), rated the relative conspicuity of the four road workers. Road worker conspicuity was maximized by the full biomotion configuration at all distances and at both sites. The addition of ankle and knee markings also provided significant benefits relative to the standard vest alone. The effects of clothing configuration were more evident at the freeway site and at shorter distances. Overall, the full biomotion configuration was ranked to be most conspicuous and the vest least conspicuous. These data provide the first evidence that biomotion effectively enhances conspicuity of road workers at open-road work sites.     

Structural assessment of microvascular self-healing laminates using progressive damage finite element analysis

This paper presents a progressive damage analysis methodology to numerically analyse the effect of microvascular open channels on the structural properties of self-healing fibre–polymer laminates. The tensile and compression properties of self-healing carbon–epoxy laminates containing microvascular systems are analysed using finite element models which consider progressive in-plane ply damage and intra-ply damage (matrix and delamination cracking). The models predict with good accuracy (often within 5%) the stiffness and strength of laminates containing circular or elliptical microvascular channels of different sizes and orientations. The model calculates a progressive reduction in structural properties with increasing size of microvascular channels due to increased ply waviness, which was confirmed using experimental property data. The model also predicts the location and progression of damage under increasing tensile or compression loading to final failure. The model has application as a tool for the design of microvascular systems in self-healing composites used for structural applications.