Microcapsule production by an hybrid colloidosome-layer-by-layer technique

Although many different methods for microencapsulation are known only some of them had been applied at industrial scale, due to complexity, lack of mechanical strength of the resulting capsules, and the costs related to their production. One of such methods is the electrostatic layer-by-layer (LbL) adsorption, which produce shells from oppositely charged polymers. The thickness of those shells can be tuned with nanometric precision, but to build enough strength for practical applications requires the adsorption of an impractical number of layers. We present here a method to produce strong microcapsules combining the assembly of a protein/pectin shell via electrostatic LbL adsorption with the adsorption of bigger charged colloidal particles. Those colloidal particles do not need any pretreatment to modify their wettability, as would be the case for a standard colloidosome route. In this way strong encapsulates with porous walls are obtained, which can be used as easy to load scaffolds. The pores in the walls can be closed through subsequent adsorption of more layers of protein and pectin. Since the assembly scheme occurs at pH 3.5 we expect the produced microcapsules to act as an effective delivery system in food products, protecting their contents from the acidity of the stomach and dissolving later at the small intestine. The proteins and pectins used as basic building blocks are food-grade and inexpensive.     

Coarsening Investigations of Precipitates in PM Tool Steel Grades: an Effect of Nitrogen

We present experimental and theoretical comparisons of the coarsening rate for the MX (X?=?C, N or C?+?N) precipitate in five different tool steel grades produced by Powder Metallurgy (PM). The alloys contain different amounts of nitrogen and carbon; ranging from high carbon/low nitrogen to high nitrogen/low carbon. Common for the grades is a high amount of precipitate forming alloying elements resulting in a high fraction of hard phase. Experimentally we have found out that the nitrogen rich precipitates coarsen slower, both for higher and lower carbon content, than the carbon rich precipitates. Coarsening simulations are performed utilizing the DICTRA software and an agreement between calculations and measurements can be concluded.     

Temperature influence on involute gear measurements

Forschung im Ingenieurwesen - Involute gears are high-stress components used in a variety of drivetrain applications. Small manufacturing tolerances require low measurement uncertainties...     

The effects of cereal additives in low-fat sausages and meatballs. Part 1: Untreated and enzyme-treated rye bran

Rye bran was added to frankfurter-type sausages and meatballs with the aim of producing low-fat products with increased dietary fibre content. The addition of untreated rye bran to sausages was detrimental, causing a substantial increase in frying loss (20% compared to 13.2%). The addition of rye bran treated with hydrolytic enzymes reduced the frying loss to 15.2–16.4%. The firmness was also improved by the treatments (12.8–14.2 N compared to 8.8 N). Enzymatic treatment of rye bran did not however improve the water-holding capacity or the texture of sausages compared to the rye bran that had only been soaked in water. The reason could be that enzymes degraded the solubilized fraction of the dietary fibre, leaving small fragments that cannot contribute to the water-holding capacity and the texture of the sausages. The benefits of treating rye bran in water were not seen in meatballs, probably due to the more particulate structure of meatballs, which is not as sensitive to additives.     

Calculation of double layer interaction between colloidal aggregates

This paper examines the interaction between the electric double layers of aggregates. Commonly, rather simplified models are used like the approximation of primary particle interaction (APPI), which just considers the interaction of the closest pair of primary particles having a double layer as if they were isolated. However, for nanoparticles the double layer thickness may be in the same order of magnitude as the particle size or even larger, what leads to a considerable double layer overlap inside the aggregates and between two interacting aggregates. Consequently, such approximations will fail. The paper presents a numerical scheme for the double layer interaction of arbitrarily shaped aggregates, which can e.g. help to establish criteria for the applicability of approximate models. The calculation employs a singularity method, which is based on the linearised Poisson–Boltzmann equation. Additionally, a linear model for charge regulation is implemented. The impact of charge regulation and double layer thickness were studied for fractal DLCA aggregates and hexagonal closed-packed aggregates.     

Cu/Ni‐Loaded CeO2‐ZrO2 Catalyst for the Water‐Gas Shift Reaction: Effects of Loaded Metals and CeO2 Addition

Two different types of metals (Cu and Ni) and the effect of CeO₂ addition to produce a CeO₂‐ZrO₂ co‐supporter were investigated through the water‐gas shift (WGS) reaction. It was found that the WGS activity could be enhanced with CeO₂ addition. At relatively high temperature, Ni‐loaded catalysts exhibited higher CO conversion while Cu‐loaded catalysts demonstrated better performance at low temperatures. The stability and yield of the CO₂ and H₂ products of the Cu catalysts were higher than those of the Ni catalysts. These results may be caused by an irreversible adsorption of CO on Ni and the reverse WGS reaction occurring on the Ni catalysts. In situ diffuse‐reflection infrared Fourier transform spectroscopy data suggests that the WGS mechanism likely proceeded via formate species.     

Effect of NiO-to-Ni Transformation on Conductivity and Structure of Yttria-Stabilized ZrO2

The conductivity and structure of 8-mol%-yttria-stabilized zirconia with additions of nickel oxide has been investigated, both in the as-prepared state and after reduction of NiO in hydrogen. During reduction at 1000°C, the conductivity decreases by 40%–50% and most of the NiO dissolved in the zirconia is exsolved in the form of nickel particles. This is accompanied by the formation of tetragonal zirconia precipitates of size 10–40 nm and by an increase in the lattice parameter. On reoxidation in air at 1000°C, the change in lattice parameter is partly reversed, but the conductivity shows no further changes.     

A new enzymatically produced 1-lactulose: A pilot study to test the bifidogenic effects

In a novel pilot plant scale process, lactulose was synthesized enzymatically, operating a maximum batch volume of 170 L. The test product was subjected to a randomized, double-blind, placebo-controlled pilot feeding study. Participants consumed a milk serum drink for 14 days, equalling a daily intake of about 3 g d⁻¹ galactosyl-fructoses. Additionally, the effect of industrially produced lactulose and a placebo drink without lactulose was determined. So far, clinical studies on the prebiotic action of lactulose only focussed on the effects of industrially generated lactulose. The intake of enzymatically synthesized lactulose significantly increased (p = 0.001) faecal bifidobacterial counts, while there was no difference with industrially produced lactulose. Analysis of the compounds showed that the drink with enzymatically synthesized lactulose contained an additional disaccharide, β-1,1-galactosyl-fructose. Presumably, this sugar has a bifidogenic effect and may represent a novel prebiotic.     

The nature of polymer grafts and substrate shape on the surface degradation of poly(l‐lactide)

Surface grafting of functional polymers is an effective method to alter material properties and degradation behavior. Two different substrate shapes of poly(l ‐lactide) (PLLA), i.e., films and microparticles, were surface‐grafted with hydrophilic monomers, and their surface degradation was monitored. Surface grafting with a hydrophilic and acidic polymer graft [acrylic acid (AA)] induced large alterations in the surface morphology and topography of the films. In contrast, hydrophilic and neutral polymer grafts [acrylamide (AAm)] had no significant effect on the surface degradation behavior, while the PLLA reference and co‐monomeric (AA/AAm) polymer‐grafted samples exhibited intermediate surface degradation rates. The grafted PAA chains induced a local acidic environment on the surface of the substrates, which in turn catalyzed the surface degradation process. This effect was more pronounced in the films than in the microparticles. Thus, the nature of the grafted chains and substrate geometry were shown to affect the surface degradation behavior of PLLA substrates. © 2015 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42736.