Enzymic Hydrolysis and Industrial Importance of Barley β-Glucans and Wheat Flour Pentosans

Mixed linkage β-glucane and pentosanes (mainly arabinoxylanes) are the major endosperm cell-wall polysaccharides of barely and wheat respectively. These polysaccharides, although minor components of the whole grain, significantly affect the industrial utilization of these cereals. The modification of barley corns during malting requires the dissolution of the β-glucane in the cell-wall of the starch endosperm. High β-glucane concentration in wort and beer effect the rate of filtration and can also lead to precipitate or gel formation in the final product. In a similar manner, pentosane is thought to cause filtration problems with wheat starch hydrolysates by increasing viscosity and by producing gelatinous precipitate which blocks filters. Ironically, it is this same viscosity building and water binding capacity which is considered to render pentosanes of considerable value in dough development and bread storage (anti-staling functions). In the current paper, some aspects of the beneficial and detrimental effects of pentosanes and β-glucane in the industrial utilization of wheat and barley are discussed. More specifically, enzymic methods for the preparation, analysis and identification of these polysaccharides and for the removal of their functional properties, are described in detail.     

The effect of dietary supplementation with eicosapentaenoic acid on the phospholipid and fatty acid composition of erythrocytes of marmoset

Adult male marmoset monkeys were fed eicosapentaenoic acid (20∶5n−3) as the ethyl ester in diets containing either 32% (reference diet, no added cholesterol) or 7% (atherogenic diet with 0.2% added cholesterol) linoleic acid (18∶2n−6) for 30 wk. No changes were seen in the level of phosphatidylcholine (PC) or phosphatidylethanolamine (PE) but minor changes were observed in both the sphingomyelin (SPM) and phosphatidylinositol plus phosphatidylserine (PI+PS) fractions of erythrocyte lipids. The extent of total n−3 fatty acid incorporation into membrane lipids was higher in atherogenic diets (polyunsaturated/monounsaturated/saturated (P/M/S) ratio 0.2∶0.6∶1.0) than reference diets (P/M/S ratio 1∶1∶1) and this was true for both PE (33.4±1.0%vs 24.3±1.1%) and PC (9.3±0.5%vs 4.9±0.3%). Although suitable controls for cholesterol effects were not included in the study, earlier results obtained with marmosets lead us to believe such effects were probably small. Regardless of basic diet (atherogenic, reference), 20∶5n−3 was preferentially incorporated into PE (10.8±0.2%, 6.0±0.02%) while smaller amounts were incorporated into PC (6.9±0.4%, 3.2±0.2%). The major n−3 polyunsaturated fatty acid found in PE in response to dietary 20∶5n−3 was the elongation metabolite 22∶5n−3 in both the atherogenic (17.7±0.7%) and reference (14.3±1.0%) dietary groups; 22∶6n−3 levels were less affected by diet (4.7±0.3% and 3.9±0.2%, respectively). The results can be interpreted to indicate an inverse relationship between the amount of dietary 18∶2n−6 and incorporation of 20∶5n−3 into erythrocyte membrane phospholipids regardless of whether the major dietary n−3 fatty acid was α-linolenate (18∶3n−3) or 20∶5n−3. This interpretation is supported by theoretical calculations.     

Paradoxical effect of n−3-containing vegetable oils on long-chain n−3 fatty acids in rat heart

Flaxseed, echium, and canola oils contain α-linolenic acid (18∶3n−3, ALA) in a range of concentrations. To examine their effect on elevating cardiac levels of long-chain n−3 FA, diets based on these n−3-containing vegetable oils were fed to rats for 4 wk. Sunflower oil, which contains little ALA, was a comparator. Despite canola oil having the lowest ALA content of the three n−3-containing vegetable oils, it was the most potent for elevating DHA (22∶6n−3) levels in rat hearts and plasma. However, the relative potencies of the dietary oils for elevation of EPA (20∶5n−3) in heart and plasma followed the same rank order as their ALA content, i.e., flaxseed>echium>canola>sunflower oil. This paradox may be explained by lower ALA intake leading to decreased competition for Δ6 desaturase activity between ALA and the 24∶5n−3 FA precursor to DHA formation.     

Δ6 Desaturase mRNA Abundance in HepG2 Cells Is Suppressed by Unsaturated Fatty Acids

The effect of unsaturated fatty acids on the abundance of Δ6 desaturase (D6D) mRNA and the fatty acid composition of HepG2 cell membranes was examined. Supplementation of HepG2 cells with oleic acid (18:1n-9, OA), linoleic acid (18:2n-6, LA), α-linolenic acid (18:3n-3, ALA), arachidonic acid (20:4n-6, AA) or eicosapentaenoic acid (20:5n-3, EPA) reduced D6D mRNA abundance by 39 ± 6.6, 40 ± 2.2, 31 ± 5.2, 55 ± 4.8, and 52 ± 5.0%, respectively, compared with control cells. Despite the reduction in D6D mRNA abundance, the level of D6D conversion products (20:3n-9, EPA and AA) in OA, ALA and LA supplemented cells, respectively, was elevated above that in control cells. Our results suggest that although unsaturated fatty acids decrease the abundance of D6D mRNA by as much as 50%, the conversion of polyunsaturated fatty acids and accumulation of long chain polyunsaturated fatty acids (LCPUFA) in HepG2 cell phospholipids continues to occur.     

Comparative physiology and fermentation performance of Saaz and Frohberg lager yeast strains and the parental species Saccharomyces eubayanus

Two distinct genetic groups (Saaz and Frohberg) exist within the hybrid Saccharomyces pastorianus (S. cerevisiae × S. eubayanus) taxon. However, physiological/technological differences that exist between the two groups are not known. Fermentative capability of the parental S. eubayanus has likewise never been studied. Here, 58 lager strains were screened to determine which hybrid group they belonged to, and selected strains were characterized to determine salient characteristics. In 15 °P all‐malt wort fermentations at 22 °C, Frohberg strains showed greater growth and superior fermentation (80% apparent attenuation, 6.5% alcohol by volume in 3–4 days) compared to all other strains and maintained highest viability values (>93%). Fermentation with S. eubayanus was poor at the same temperature (33% apparent attenuation, 2.7% alcohol by volume at 6 days and viability reduced to 75%). Saaz strains and S. eubayanus were the least sensitive to cold (10 °C), though this did not translate to greater fermentation performance. Fermentation with S. eubayanus was poor at 10 °C but equal to or greater than that of the Saaz strains. Performance of Saaz yeast/S. eubayanus was limited by an inability to use wort maltotriose. [¹⁴C]‐Maltotriose transport assays also showed negligible activity in these strains (≤0.5 µmol min^?1 g^?1 dry yeast). Beers from Saaz fermentations were characterized by two‐ to sixfold lower production of the flavour compounds methyl butanol, ethyl acetate and 3‐methylbutyl acetate compared to Frohberg strains. Higher alcohol and ester production by S. eubayanus was similar to that of Frohberg strains. Copyright © 2013 John Wiley & Sons, Ltd.     

<Emphasis Type="Italic">In Situ</Emphasis> Observation of Strain Evolution in Cp-Ti Over Multiple Length Scales

The strain evolution in polycrystalline CP-Ti strip under tension was studied in situ and at two length scales using Synchrotron X-ray diffraction. To establish the bulk material behavior, experiments were performed at the Australian Synchrotron facility. Because of the relatively large grain size, discontinuous “spotty” Debye ring patterns were observed, and a peak fitting algorithm was developed to determine the individual spot positions with the necessary precision for strain determination. The crystallographic directional dependence of strain anisotropy during the loading cycle was determined. Strain anisotropy and yielding of individual crystallographic planes prior to the macroscopic yield point were further clarified by in situ loading experiments performed at the Advanced Light Source (ALS). The deviatoric strain accumulation and plastic response were mapped on a grain-by-grain basis. The onset of microscopic yielding in the grains was identified and correlated with the relative orientation of the grains with respect to the loading direction.     

To use or not to use: Clinicians' perceptions of telemental health.

Equal access to mental health services is necessary for healthy individuals and communities. However, due to geographical distances and other barriers, some clients cannot easily access mental health professionals. Technologies such as videoconferencing for clinical purposes (i.e., telemental health) may help to bridge these gaps to connect clients and clinicians at geographically diverse locations. However, despite its potential utility, telemental health has not been widely adopted in Canada. This study is an exploratory investigation into mental health professionals' attitudes toward telemental health, factors that affect the frequency with which they use this technology, and their perceptions of individual characteristics that make clients more or less suitable candidates for telemental health. This study has a particular focus on remote and rural and Operational Stress Injury (OSI) contexts. One hundred sixty mental health workers across Canada participated in an online survey, and 25 mental health workers from Operational Stress Injury clinics across Canada participated in in-person interviews. The data were examined using qualitative and quantitative analysis methods. Findings suggest that mental health workers have overall positive attitudes toward the use of telemental health—particularly for clients in remote and rural locations. Additionally, receiving training in telemental health, being in the mental health field for longer, and perceiving the technology as easy to use are associated with more frequent use of telemental health. Finally, clinicians reported specific client characteristics that they perceive to make some clients unsuitable candidates for telemental health. Implications of these findings and directions for future research are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Mentoring students and professionals with disabilities.

Mentoring can have a significant positive impact on the lives of individuals. People with disabilities seeking to locate mentors face a variety of potential challenges and benefits. This article addresses mentoring-related issues faced by professionals with disabilities. The article presents a model of mentoring and discusses the difficulties faced by individuals with disabilities in locating mentors. It describes the negative impact of the lack of available mentors upon the educational and vocational development of people with disabilities. It offers effective strategies aimed at enhancing mentoring relationships with people with disabilities, including macrofocused strategies capable of enhancing the effectiveness of disability-related mentoring programs and microfocused strategies useful in developing quality mentoring relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)