Extrusion processing of green biocomposites: Compounding,fibrillation efficiency,and fiber dispersion

The efficiency of twin‐screw extrusion process to fibrillate cellulose fibers into micro/nanosize in the same step as the compounding of green bionanocomposites of thermoplastic starch (TPS) with 10 wt % fibers was examined. The effect of the processing setup on micro/nanofibrillation and fiber dispersion/distribution in starch was studied using two types of cellulose fibers: bleached wood fibers and TEMPO‐oxidized cellulose fibers. A composite with cellulose nanofibers was prepared to examine the nanofiber distribution and dispersion in the starch and to compare the properties with the composites containing cellulose fibers. Optical microscopy, scanning electron microscopy, and UV/Vis spectroscopy showed that fibers were not nanofibrillated in the extrusion, but good dispersion and distribution of fibers in the starch matrix was obtained. The addition of cellulose fibers enhanced the mechanical properties of the TPS. Moisture uptake study revealed that the material containing TEMPO‐oxidized fibers had higher moisture absorption than the other composites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39981.     

The effect of ageing time on co-precipitated Cu/ZnO/ZrO2 catalysts used in methanol synthesis from CO2 and H2

The effect of suspension ageing time during the catalyst precipitation process on the performance of co-precipitated Cu/ZnO/ZrO₂ catalysts in methanol synthesis from CO₂ and H₂ has been studied. The ageing time influenced greatly the physical and chemical characteristics of the catalysts as well as their activity in the methanol synthesis. Prolonged ageing was advantageous, mainly due to both lower sodium contents and enhanced crystallinity of the catalysts.     

Muscle fiber properties and thermal stability of intramuscular connective tissue in porcine M. semimembranosus

BACKGROUND: Strips can be easily peeled from raw destructured pork (M. semimembranosus, SM muscle) by hand but in normal meat these strips break. In general, destructured meat is pale in color. Porcine SM muscles have thick muscle fibers which could predispose them to destructuration. This study investigated whether the onset and peak temperatures of thermal shrinkage (T_o and T_p) of intramuscular connective tissue from SM muscles were associated with muscle fiber thickness, capillary density or extracellular space. We also investigated whether these muscle fiber properties of destructured muscles differed from those of normal muscles. RESULTS: The destructured and normal muscles were similar in muscle fiber cross‐sectional area, capillary density, extracellular space and sarcomere length. T_o correlated negatively with sarcomere length. The water content of differential scanning calorimetry samples consisting of intramuscular connective tissue was higher in destructured muscles than in normal muscles. CONCLUSION: Muscle fiber properties (muscle fiber cross‐sectional area and sarcomere length) and capillary density are similar in destructured and normal SM muscles. T_o and T_p of intramuscular connective tissue are similar in destructured and normal muscles. Muscle fiber properties show no association with the thermal shrinkage properties of intramuscular connective tissue. Copyright © 2009 Society of Chemical Industry     

High post-mortem temperature combined with rapid glycolysis induces phosphorylase denaturation and produces pale and exudative characteristics in broiler Pectoralis major muscles

This study investigated the effect of early post-mortem temperature on broiler protein characteristics and meat quality. Muscles were kept at different temperatures (0, 20 and 40 °C) until 4h post-mortem and then stored at 4 °C. Rapid degradation of ATP and glycogen, thus inducing a high rate of lactate formation and pH drop, were found in the 40 °C group during incubation. When extracting proteins, a lower protein content of the sarcoplasmic fraction and a higher protein content of the myofibrillar fraction were found in the 40 °C group at 24h post-mortem; SDS-PAGE and western-blotting results revealed that phosphorylase was associated with the myofibrillar fraction. Furthermore, the 40 °C group had paler surfaces, higher drip loss and lower processing properties. These data suggest that elevated temperature during early post-mortem period, resulting in rapid glycolysis, induced phosphorylase denaturation and association with myofibrillar proteins thus generating pale and exudative characteristics.     

Using nitrogen isotope fractionation to assess the oxidation of substituted anilines by manganese oxide

We explored the N isotope fractionation associated with the oxidation of substituted primary aromatic amines, which are often the position of initial attack in transformation processes of environmental contaminants. Apparent (15)N-kinetic isotope effects, AKIE(N), were determined for the oxidation of various substituted anilines in suspensions of manganese oxide (MnO(2)) and compared to reference experiments in homogeneous solutions and at electrode surfaces, as well as to density functional theory calculations of intrinsic KIE(N)for electron and hydrogen atom transfer reactions. Owing to the partial aromatic imine formation after one-electron oxidation and corresponding increase in C-N bond strength, AKIE(N)-values were inverse, substituent-dependent, and confined to the range between 0.992 and 0.999 in agreement with theory. However, AKIE(N)-values became normal once the fraction of cationic species prevailed owing to (15)N-equilibrium isotope effects, EIE(N), of 1.02 associated with N atom deprotonation. The observable AKIE(N)-values are substantially modulated by the acid/base pre-equilibria of the substituted anilines and isotope fractionation may even vanish under conditions where normal EIE(N) and inverse AKIE(N) cancel each other out. The pH-dependent trends of the AKIE(N)-values provide a new line of evidence for the identification of contaminant degradation processes via oxidation of primary aromatic amino groups.     

Effect of sodium citrate, carboxymethyl cellulose and carrageenan levels on quality characteristics of low-salt and low-fat bologna type sausages

Quality characteristics of low-salt bologna-type sausage manufactured with sodium citrate (NAC), carboxymethyl cellulose (CMC) and carrageenan (CAR) were examined. Three levels of salt, NAC, CMC and CAR, and two levels of fat were used. Batter and sausage pH values were measured and the frying loss of sausages was analysed by frying slices in an electric grill. Firmness, juiciness, saltiness and flavour intensity of the sausages were sensorically evaluated. Altogether 20 separate sausage batches were prepared. In low-salt sausages containing less than 1.4% NaCl, the use of NAC, CAR and CMC decreased frying loss and increased saltiness. NAC and CAR also increased flavour intensity, but CMC did not. Furthermore, NAC, CAR and CMC increased the firmness of the low-salt sausage, while only NAC increased juiciness when the NaCl content was below 1.4%. NAC increases, however, the sodium content of the product. Therefore, it can be concluded that in low-salt sausages no additive alone is suitable. A mixture of NAC and CAR appears to be the best combination.     

Solubility and fractionation of lipides in sulfur dioxide

Summary The solubilities of several fatty acids and their methyl esters in SO₂ have been determined as a function of temperature. SO₂ dissolves much smaller amounts of acid than the organic solvents commonly used with lipides. In this respect it resembles solvents of high polarity, such as nitromethane, acetonitrile, or furfural. Methyl esters are more than a hundred times more soluble in SO₂ than are the acids. Acids, methyl esters, and glycerides can be fractionated efficiently in this solvent. Project supported in part by a grant from the Fish and Wildlife Service, U.S. Department of the Interior, and by the Hormel Foundation.     

KidStory: a technology design partnership with children

We present a new design method that is used within the KidStory project to enable a large number of young children to participate as partners in the design of advanced storytelling technology. The method is an adaptation of the cooperative inquiry method for school environments and uses a combination of evaluation, brainstorming and traditional education methods. These activities have lead to the elaboration of new ideas, impacted the design of existing software and produced a number of interesting new technology designs.