Emulsifying properties of β-lactoglobulin and Quillaja bark saponin mixtures: Effects of number of homogenization passes,pH, and NaCl concentration

The effects of number of homogenization passes, pH, and NaCl concentration on the formation and stability of oil-in-water emulsions comprising a mixture of a biosurfactant (Quillaja bark saponin) and a globular protein (β-lactoglobulin) were investigated. The emulsions were characterized as to visual appearance, droplet size, droplet surface charge, and rheology. The emulsions obtained by different conditions (4, 6, or 8 passes; pH 7, 8, or 9; and 0, 100, or 200 mmol L^?1 of NaCl) were polydisperse, presented relatively small average droplet sizes (z-average < 323 nm) as well as negative droplet charge (between –20 and –79.6 mV) in all evaluated conditions. Regardless of the number of homogenization passes, the emulsions exhibited low apparent viscosity and pseudoplastic behavior with small yield stress. Viscoelastic behavior was also observed, thus the emulsions were characterized as weak gels. Four homogenization passes were enough to obtain small droplets in the evaluated conditions. Droplet size was not significantly affected by NaCl concentration and pH (p > 0.05). On the other hand, the absolute ζ-potential values significantly decreased and increased upon increased NaCl content and pH, respectively. Regardless of the tested conditions, all emulsions had good stability against phase separation and droplet aggregation, since no significant changes in average droplet size were observed throughout storage (p > 0.05). In the presence of NaCl, in which droplet charge significantly decreased, emulsion was also stable. Thus, we can conclude that electrostatic repulsion as well as steric repulsion was responsible for stabilization.     

Comparison of two models for the estimation of usual intake addressing zero consumption and non-normality

Various models exist for estimating the usual intake distribution from dietary intake data. In this paper, we compare two of these models, the Iowa State University Foods (ISUF) model and the betabinomial-normal (BBN) model and apply them to three different datasets. Intake data are obtained by aggregating over multiple food products and are often non-normal. The ISUF and BBN model both address non-normality. While the two models have similar structures, they show some differences. The ISUF model includes an additional spline transformation for improving the normality of the intake amount distribution, while the BBN model includes the possibility of addressing covariates, such as age or sex. Our analyses showed that for two of the example datasets both models produced similar estimates of the higher percentiles of the usual intake distribution. However, for the third dataset, where the intake amount distribution appear to be multimodal, both models produced different percentile estimates.     

Study of a new energy efficient process for French fries production

A new, energy efficient production process for French fries was developed and evaluated. Superheated steam (SHS) was used for evaporation of water instead of pre-drying with air and par-frying with oil. The product was frozen by vacuum cooling. Unfortunately, with this process it was not possible to reach the quality of conventional French fries. Sensory analysis indicated that the main quality defect was a tough crust with a fatty appearance. Confocal Scanning Laser Microscopy showed that this was caused by skin formation on the surface during both SHS drying and vacuum cooling. A frying step was necessary to obtain a porous crust. A satisfactory product quality was feasible after drying with SHS instead of air. Due to the concessions made for the product quality, the final energy reduction was limited. Nevertheless, this study has gained more insight into how processing affects potato tissue on micro-scale and it has shown that a porous structure is essential for good quality French fries.     

Double emulsions (W/O/W): physical characteristics and perceived intensity of salty taste

This study addressed the correlation between physical characteristics of double emulsions and sensory perception, as the microstructure of these systems may provide the mechanism to understanding the initial cause of the altered salty taste. Thus, double emulsions (W/O/W) were prepared using different volumes of the internal aqueous phase while maintaining the same fat and sodium contents in the evaluated systems. Polyglycerol polyricinoleate (PGPR) and tween 80 were used as hydrophobic and hydrophilic emulsifiers, respectively. After preparation, the samples were stored at 25 °C for 4 days and submitted to analysis of optical microscopy, distribution and polydispersity of the oil droplets size, electrical conductivity, rheological behaviour and sensorial analysis. It was found that the use of different emulsifier concentrations (PGPR) did not influence the physical characteristics of the emulsions with the same formulation, but emulsions with different internal aqueous phase concentrations presented different results. These distinct characteristics may have influenced sensorial perception, as the emulsion with higher internal phase concentration was considered saltier. Thus, it can be concluded that structural differences of the double emulsions can be used to decrease the sodium contents without perceivable changes in salty taste.     

The "lazy-V" de-epithelialised turn-over fasciocutaneous flap in the reconstruction of skin defects after tendo Achilles repair

Few methods of closure of skin defects lying over the tendo Achilles have been described. The de-epithelialised turn-over flap is one of them but it cannot be used in the presence of a scar proximal to the defect. We describe a modification ("The Lazy-V") of the de-epithelialised turn-over flap which gives it a rotation arc, thus enhancing the versatility of the procedure. This modification is presented with an illustrative case report and a review of the literature.     

Colloidal organic matter fouling of UF membranes: role of NOM composition & size

The aim of this study was to fractionate pre-filtered surface water using a 3.5 and a 10 kDa dialysis membrane, and to compare the rate of fouling and the fouling reversibility/irreversibility of the NOM fractions. Trial dialyses (3.5 and 10 kDa) were carried out for 6 and 21 days with pre-filtered surface water using synthetic surface water as dialysate. The aim of the trials was to optimize the dialysis process for NOM fractionation. DOC, Ca²⁺, Mg²⁺, soluble silica and bacteria were monitored at intervals during the dialysis process. Thereafter, the various NOM fractions (with low and high Ca²⁺) were fed to a miniature UF system operated at a constant flux of 138.5 L/m2 h, filtration cycle times of 31.5 min and backwash duration of 1.75 min. A PES/PSV hollow fiber UF membrane (MWCO 100 kDa) with a surface area of 0.0125 m² was employed for the filtration tests (X-Flow). Transmembrane pressure (TMP) and UF feed and permeate (LC-OCD) were monitored at regular intervals. For a dialysate recirculation of 95 L/h, sample to dialysate ratio of 5.2:80 L and a dialysate change frequency of 3 times per 24 h, the shortest duration of dialysis was about 6–7 days for both 3.5 and 10 kDa dialyses membranes. The removal of organic carbon (OC) increased with dialysis duration and MWCO of the bags. The biopolymer fraction increased from 120% to 240% when the duration of dialysis was increased from 6 days (1.1 mg DOC/L, 151 mg Ca/L) to 21 days (0.82 mg DOC/L, 133 mg Ca/L) with the 10 kDa dialysis membrane. The increased biopolymer fraction in the NOM sample that was dialyzed for 21 days resulted in a doubling of the fouling rate from 3.5 to 6.6 mbar/min per mg DOC/L. The other NOM fractions (humics and building blocks) and the Ca/DOC ratio was more or less the same in both NOM samples suggesting that biopolymers were the major cause of UF fouling.     

Changes in lipid content,fatty acid composition and lipoprotein lipase activity in dry goat omental adipose tissue according to tissue site

Water and lipid contents, fatty acid distribution, and lipoprotein lipase activity were determined in 11 samples taken from theOmentum Majus of five dry Alpine goats. Samples were chosen to standardize sampling sites using geometric guide marks representative of different adipose tissue sites. Sample location explained between 20% and 30% of the total variance in water and lipid contents and in lipoprotein lipase activity, and from 5.5% to 45.4% of the total variance in fatty acid distribution. Increased sample thickness was associated with an increase in lipid content and in saturated fatty acid percentages. Samples taken in proximity of the omentum tissue attached to the rumen and abomasum had the highest content. We furthermore found that the levels of 18∶2n−6, 18∶1n−7, and of branched chain fatty acids were high close to a pila of the rumen which also corresponded to high lipoprotein lipase activity. Concomitant high levels of 16∶1n−7, 17∶1n−8, and 18∶1n−9 may reflect high levels of Δ9 desaturase activity.     

Volatiles from Psylla-Infested Pear Trees and Their Possible Involvement in Attraction of Anthocorid Predators

Previous work showed that anthocorid predators aggregate around gauze cages containing Psylla-infested trees in a pear orchard. Because anthocorids responded to odor from Psylla-infested leaves in a laboratory test, it was hypothesized that these aggregative responses in the field were triggered by olfaction of compounds associated with Psylla injury. We present chemical analyses of volatiles from damaged and undamaged plants and studies on behavioral responses of anthocorid predators to compounds released by damaged plants. Leaf headspace volatiles from clean and Psylla-infested pear trees were collected on Tenax and identified by GC-MS after thermodesorption. Twelve volatiles were found exclusively in headspace samples from Psylla-infested leaves. Six were present in significantly higher quantities in samples from infested leaves: the monoterpene, (E,E)-α-farnesene, the phenolic, methyl salicylate, and the green leaf compounds, (Z)-3-hexen-1-yl acetate, (Z)-3-hexen-1-ol, 1-hexyl-acetate, and 1-penten-3-ol. These compounds are known to be produced by plants, and damage by pear psyllids seems to trigger their emission. Blend composition varied and was partly correlated with tree or leaf age and degree of Psylla infestation. To study whether compounds associated with leaf injury elicit olfactory responses in anthocorid predators, apple-extracted (E,E)-α-farnesene, synthetic methyl salicylate, and (Z)-3-hexen-1-yl acetate were offered in a Y-tube olfactometer to field-collected adult Anthocoris spp. Significant positive responses were found to both the monoterpene and the phenolic, but not to the green leaf volatile. The results lend support to the hypothesis that predator attraction to herbivore-infested pear trees is mediated by herbivory-induced plant volatiles.     

Synthesis of amphiphilic triblock copolymers for the formation of magnesium fluoride (MgF2) nanoparticles

A series of amphiphilic poly(2‐hydroxyethyl methacrylate)‐b‐polydimethylsiloxane‐b‐poly(2‐hydroxyethyl methacrylate) (pHEMA‐b‐PDMS‐b‐pHEMA) (A‐B‐A) triblock copolymers were synthesized from three different carbinol‐terminated polydimethylsiloxanes with varying molecular weight. A carbinol‐terminated polydimethylsiloxane was modified with 2‐bromoisobutyryl bromide to obtain a macroinitiator. The block copolymers were characterized by NMR, GPC, and dynamic light scattering (DLS). Reverse micelles of a copolymer were formed in mixture of benzene/methanol solution which served as nanoreactors for the synthesis of magnesium fluoride (MgF₂) nanoparticles. The MgF₂ was prepared via chemical precipitation using magnesium chloride and potassium fluoride as reactants. The MgF₂‐triblock copolymer composites were synthesized as a function of MgF₂–weight ratio (0.5, 5, and 10 wt%) in copolymer. The MgF₂ colloids were dissolved in three organic solvents: methanol, isopropanol, and tetrahydrofuran. The polymer nanoparticles were characterized by DLS, transmission electron microscopy, thermogravimetric analysis, and X‐ray diffraction (XRD) analysis. The formation of MgF₂ crystals was observed by XRD. Particle size and particle size distribution showed significant changes in different solvents. The thermal stability of MgF₂ colloids increased as the amount of nanoparticle increased in polymeric matrix. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Identification of Small Molecules that Interfere with H1N1 Influenza A Viral Replication

Successful replication of the influenza A virus requires both viral proteins and host cellular factors. In this study we used a cellular assay to screen for small molecules capable of interfering with any of such necessary viral or cellular components. We used an established reporter assay to assess influenza viral replication by monitoring the activity of co‐expressed luciferase. We screened a diverse chemical compound library, resulting in the identification of compound 7 , which inhibits a novel yet elusive target. Quantitative real‐time PCR studies confirmed the dose‐dependent inhibitory activity of compound 7 in a viral replication assay. Furthermore, we showed that compound 7 is effective in rescuing high‐dose influenza infection in an in vivo mouse model. As oseltamivir‐resistant influenza strains emerge, compound 7 could be further investigated as a new and potentially suitable scaffold for the development of anti‐influenza agents that act on novel targets.