Second order Raman spectroscopy of the wurtzite form of GaN

We report on Raman scattering by phonon pairs in GaN films grown on sapphire substrates by plasma‐enhanced molecular beam epitaxy. The first order data are consistent with results obtained from GaN bulk crystals of the wurtzite structure. The A1 and the much weaker E2 symmetry components of the second order scattering have been identified. Two‐phonon spectra are dominated by contributions due to longitudinal optical phonons. © 1995 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70248/2/JAPIAU-77-11-6042-1.pd

Microwave dielectric relaxation & polarization study of binary mixture of methylethylketone with nitrobenzene

Present paper reveals detailed study of dielectric relaxation and dielectric polarization and physicochemical study of binary polar-polar liquid mixture i.e. dielectric constant, relaxation time, viscosity, density of methylethylketone (MEK) with nitrobenzene (NB) at 303 K. The measured dielectric and physicochemical parameters employed to acquire additional derived properties like Bruggeman factor, molar refraction and excess properties like static dielectric constant, excess inverse relaxation time, excess molar volume, excess viscosity, excess molar refraction, Gibbs free energy, and enthalpy of activation. The variation of this parameters with composition of these quantities has been used to explain the type, strength and nature of intermolecular interactions between MEK+NB binary mixture. Attained results authenticate that there are strong hydrogen-bond interactions between unlike molecules of different groups of MEK+NB mixtures and that 1:1 complexes are produced and strength of intermolecular interaction rises with rise in concentration of MEK.               KEY WORDS: Bruggeman factor, Excess inverse relaxation time, Dielectric polarization Bull. Chem. Soc. Ethiop. 2019, 33(2), 349-358.DOI: https://dx.doi.org/10.4314/bcse.v33i2.1

Dietary Supplementation with Soluble Plantain Non-Starch Polysaccharides Inhibits Intestinal Invasion of Salmonella Typhimurium in the Chicken

Soluble fibres (non-starch polysaccharides, NSP) from edible plants but particularly plantain banana (Musa spp.), have been shown in vitro and ex vivo to prevent various enteric pathogens from adhering to, or translocating across, the human intestinal epithelium, a property that we have termed contrabiotic. Here we report that dietary plantain fibre prevents invasion of the chicken intestinal mucosa by Salmonella. In vivo experiments were performed with chicks fed from hatch on a pellet diet containing soluble plantain NSP (0 to 200 mg/d) and orally infected with S.Typhimurium 4/74 at 8 d of age. Birds were sacrificed 3, 6 and 10 d post-infection. Bacteria were enumerated from liver, spleen and caecal contents. In vitro studies were performed using chicken caecal crypts and porcine intestinal epithelial cells infected with Salmonella enterica serovars following pre-treatment separately with soluble plantain NSP and acidic or neutral polysaccharide fractions of plantain NSP, each compared with saline vehicle. Bacterial adherence and invasion were assessed by gentamicin protection assay. In vivo dietary supplementation with plantain NSP 50 mg/d reduced invasion by S.Typhimurium, as reflected by viable bacterial counts from splenic tissue, by 98.9% (95% CI, 98.1–99.7; P<0.0001). In vitro studies confirmed that plantain NSP (5–10 mg/ml) inhibited adhesion of S.Typhimurium 4/74 to a porcine epithelial cell-line (73% mean inhibition (95% CI, 64–81); P<0.001) and to primary chick caecal crypts (82% mean inhibition (95% CI, 75–90); P<0.001). Adherence inhibition was shown to be mediated via an effect on the epithelial cells and Ussing chamber experiments with ex-vivo human ileal mucosa showed that this effect was associated with increased short circuit current but no change in electrical resistance. The inhibitory activity of plantain NSP lay mainly within the acidic/pectic (homogalacturonan-rich) component. Supplementation of chick feed with plantain NSP was well tolerated and shows promise as a simple approach for reducing invasive salmonellosis

Phenolic, polysaccharidic and lipidic fractions of mushrooms from northeast Portugal: chemical compounds with antioxidant properties

Mushrooms do not constitute a significant portion of the human diet, but their consumption continues to increase due to their functional benefits and presence of bioactive compounds. Some of those compounds can be found in the phenolic, polysaccharidic and lipidic fractions of edible and inedible species. Herein, those fractions of five wild mushrooms (Coprinopsis atramentaria, Lactarius bertillonii, Lactarius vellereus, Rhodotus palmatus and Xerocomus chrysenteron) from Northeast Portugal were studied for their chemical composition and antioxidant properties. Protocatechuic, p-hydroxybenzoic, p-coumaric and cinnamic acids were found in the phenolic fraction, ramnose, xylose, fucose, arabinose, fructose, glucose, manose, mannitol, sucrose, maltose and trehalose were quantified in polysaccharidic fraction, linoleic and stearic (only in Lactarius sp.) acids, and β- and γ-tocopherols were the main compounds in the lipidic fraction. C. atramentaria and X. chrysenteron phenolic fractions gave the highest free radical scavenging activity, reducing properties and lipid peroxidation inhibition in brain homogenates, which is in agreement with its highest content in total phenolics. Furthermore, among the polysaccharidic fractions C. atramentaria also gave the highest antioxidant activity, which is accordingly with its highest total polysaccharides content and sugars obtained after hydrolysis.The authors are grateful to Fundação para a Ciência e a Tecnologia (FCT, Portugal) and COMPETE/QREN/EU (research project PTDC/AGR-ALI/110062/2009) for financial support. L. Barros (BPD/4609/2008) and S.A. Heleno (BD/70304/2010) also thank FCT, POPH-QREN and FSE. The GIP-USAL is financially supported by the Spanish Ministerio de Ciencia e Innovación through the Consolider-Ingenio 2010 Programme (FUN-C-FOOD, CSD2007-00063), and Junta de Castilla y León (Grupo de Investigación de Excelencia, GR133)

Physicochemical and textural quality attributes of gluten-free bread formulated with guar gum

The objective of this study was to assess the combined effect of guar gum (GG) and water content (WC) on the rheological properties of batter, and the physicochemical and textural properties of bread. Batches of gluten-free bread used a base formulation of rice (50%), maize (30%) and quinoa flour (20%), with different levels of GG (2.5, 3.0 or 3.5%) and water (90, 100 or 110%) in a full factorial design. Higher GG doses (p<0.001) tended to produce batters of lower stickiness, work of adhesion and cohesive strength; yet, of higher firmness, consistency, cohesiveness and viscosity index. These batters yielded loaves of lower (p<0.001) specific volume and baking loss; and crumbs of lower (p<0.001) aw, pH, mean cell area, void fraction, mean cell aspect ratio; and higher (p<0.001) hardness, adhesiveness, springiness, cohesiveness, chewiness, resilience, mean cell density, cell size uniformity and mean cell compactness. The sticker and less consistent batters produced with higher WC rendered larger bread loaves of softer and more cohesive and springy/resilient crumbs with greater mean cell size and void fraction. Gluten-free loaves of good appearance in terms of higher specific volume, lower crumb hardness, higher crumb springiness, and open grain visual texture were obtained in formulations with 110% WC and GG doses between 2.5 and 3.0%.Eng. Encina-Zelada acknowledges the financial aid provided by the Peruvian National Programme of Scholarships and Student Loans (PRONABEC) in the mode of PhD grants (Presidente de la República-183308). The authors are grateful to Eng. Andrea Oliveira from Prodipani, Portugal, for her kind advice and providing breadmaking ingredients.info:eu-repo/semantics/publishedVersio

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Not AvailableThe objective of this study was to investigate baking stability of nano-encapsulated spray-dried flax seed oil. Gum Arabic (GA), soy-protein isolate (SPI), sodium caseinate and sodium alginate were wall materials (20%), soy-lecithin as emulsifier and 6% flax seed oil. Powders were characterized for morphology, density, encapsulation efficiency (EE) and peroxide value. Four powders tested were below 100 nm in size with stable zeta potential values. Wall material containing GA (4%) and SPI (16%) showed highest ω−3 fatty acids (30%), encapsulation efficiency (72%) with lowest moisture (4%) and peroxide value (1.1 meq/kg). The optimized nano-particles were incorporated into eggless cake with chia (T2) to investigate their effects on physical, rheological, textural and nutritional quality and compared with control (C) made with eggs and eggless cake with chia and flax-seed powder (T1). There was no significant difference between batter of C and T2 cakes in physical and textural attributes. T2 showed higher and stable ω-3 fatty acids (25.4) after baking. ω-6 FA levels were reduced with increased antioxidant capacities in T2. Healthy ω-3 rich cake of acceptable quality characteristics meeting ω-3 requirements of vegetarians was developed using nano-encapsulated flax seed oil.Not Availabl

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Not AvailableDevelopment of new products rich in nutrients required for growth and development along with acceptability can contribute in alleviating malnutrition. Laddoo, a traditional sweet, is well-accepted by people at large. However, traditional laddoos contain one or two food groups – sugar and saturated fat, which are not healthy. The aim of this research was to formulate a nutritious laddoo using different food groups and to study its nutritional, functional, textural and sensory profile. Design/methodology/approach – Composite flour laddoo (TL) was formulated using a mix of cereals, sprouted legumes, malted millets, dairy ingredients, fruit, oil and jaggery and evaluated for particle size, colour, texture, nutritional, functional and sensory evaluation and compared with traditional wheat (CL-1) and chickpea (CL-2) flour laddoos (CL). Findings – The TL’s were significantly softer in texture compared to CLs, resulting in ease in biting, chewing and swallowing. The nutritional quality of TL was significantly higher in terms of protein (24.6 g/100 g), fibre (3.8 g/100 g), iron (10.4 mg/100 g) and phosphorus (287.5 mg/100 g). The functional quality of TL was also higher in terms of phenolics (123.0 gallic acid equivalent mg/100 g), flavonoids (6.9 quercitin equivalent mg/100 g) and antioxidant activity (62.6 per cent radical-scavenging activity). Organoleptic evaluation also showed higher acceptability (eight) of TL against six for CL-1 and seven for CL-2. Originality/value – Fortification of food products to enhance the nutritive value has become the major focus of the researchers in the field of new product development, owing to the consumer need for products having high nutritive and sensorial properties. Malnutrition is a serious matter of concern among the population of India, and the present situation demands development of products that are rich in nutrients required for growth and development and readily acceptable. Traditional laddoos made using a single ingredient does not provide sufficient nutrients, and sugar and saturated fat used for binding are not healthy options. No work on using composite flour along with sprouting/malting, jaggery and unsaturated fat to prepare laddoos with its nutritional, functional and textural properties has been reported.Not Availabl

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Not AvailableThe purpose of the study was to discover whether incorporating flours with high nutritive value along with pre-treatment of cereals with nixtamalization and sprouting of legumes would result in a highquality healthy alternative for corn-based snacks. Design/methodology/approach – Flours of nixtamalized cereals-corn, wheat, rice and sorghum and sprouted legumes-soybean and green gram are made into dough and baked instead of fried to form multigrain chips. The particle size and physical properties of flour and nutritional, functional and textural properties of dough and chips are tested to study the effect of combination of nixtamalization of cereals and sprouting of legumes in the development of chips. Findings – Baked multi-grain chips made of nixtamalized cereals and sprouted legumes had a significantly (p < 0.05) smaller particle size of 24.6 mm compared to T1 24.8 mm, C1 29.3 mm and C2 31.7 mm. T2 and C2 had significantly (p = 0.05) lower OAC value than C1 and T1 due to nixtamalization as nixtamalized flour needed half the amount of oil during dough formation. T1 showed highest calcium (mg/100 g) of 466 which was significantly (p < 0.05) higher than all other groups. The overall acceptability of T2 (8.6) was significantly (p< 0.05) higher than T1 (7.8), C2 (7.4) and C1 (6.8) on the nine-point Hedonic scale. Originality/value – The developed chips are superior in terms of higher protein and minerals with better organoleptic acceptability and lower fat content in comparison to both corn chips and nixtamalized corn chips. The multi-grain chip therefore offers a new option for the consumer in high-quality healthy alternative to corn-based fried snacks.Not Availabl

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Not AvailableThe aim of the study was to develop gluten free eggless cake using gluten free composite flour made of finger millet, sprouted soy and amaranth, for patients with celiac disease. Gluten free eggless cake prepared (T2), were analyzed for physical, textural, rheological and nutritional properties and compared with control cake (C) made using refined wheat flour and eggs and eggless composite flour cake made using whole wheat flour, malted finger millet, sprouted soy flour and amaranth (T1). There was no significant difference between T2 and C batter in terms of textural properties, flow behaviour index and consistency index. T2 had higher volume (454.4 cm3) as compared to T1 (437.1 cm3) cake. No significant differences in textural analysis were observed between cakes in terms of springiness, resilience and cohesiveness. The nutritional quality of T2 cake was significantly (p \ 0.05) higher in case of phosphorous (224.0 mg / 100 g) and iron content (7.39 mg / 100 g). Therefore, gluten free eggless cake of high nutritional composition with good quality characteristics is a good substitute for refined flour egg and composite flour eggless cake. Higher mineral content due to germinated ingredients also made it a nutritious and palatable naturally gluten free food option for the people with celiac disease.Not Availabl