Sauces and dressings: a review of properties and applications

This comprehensive review of sauces and salad dressings covers the literature over the last decade with respect to physical and chemical properties and the applications of these products. As such, texturizing and structural systems (especially hydrocolloids) are described in detail and the application of polysaccharide thickeners as texture providers is described. Microbiological aspects of sauces are covered with relevant sections discussing the factors affecting microbiological activity and microbial spoilage and/or enhancement of a range of sauces. In addition, the use of carbohydrates and proteins as emulsifiers in many sauces is described. Quality aspects are given prominence in this review with sections being devoted to rheological and textural properties, chromatographic approaches and sensory aspects. Healthy sauces such as those having low sodium, reduced fat and cholesterol or containing inulin or microcrystalline cellulose are reviewed. Finally, for various sections the trends of the main findings as well as suggestions for future research are presented.     

Parametric optimization of green synergistic reactive extraction of lactic acid using trioctylamine,Aliquat336, and butan-2-ol in sunflower oil by response surface methodology

A novel green synergistic reactive extraction technique for the removal of lactic acid (LA) from aqueous solution was explored. Response surface methodology (RSM) was applied to optimize the process variables for LA synergistic reactive extraction using a mixture of trioctylamine and Aliquat336 as extractants. During this present investigation, 2-butanol and sunflower oil were used as organic and green diluent. Systematic investigation has been carried out to obtain the optimum process conditions viz. initial LA concentration, pH of aqueous solution, extractant ratio, extractant concentration, solvent ratio, phase ratio, temperature, stirring speed, and contact time for maximizing the LA distribution coefficient (K_D) and extraction efficiency (%, η). The highest experimentally achievable LA distribution coefficient (K_D) and extraction efficiency (%) at optimized process conditions were found to be in close agreement with those predicted by numerical optimization using RSM. Thus, the results of present finding have been shown a great ability of sunflower oil as an economic and environmentally friendly green solvent for LA extraction.     

Chlorinated polyethylene nanocomposites: thermal and mechanical behavior

Chlorinated polyethylene (CPE) nanocomposites prepared with natural and organically treated montmorillonite (MMT) clays by solution intercalation method were investigated. X-ray diffraction and transmission electron microscopy techniques showed separation of organically modified clay MMT layers and indicated formation of exfoliated nanocomposites. Fourier transform infrared spectroscopy results showed interaction between the CPE matrix and the clay intercalants of Cloisite^® 30B and Cloisite^® 15A (natural MMT modified with quaternary ammonium salts). Organically treated MMT clays were found to be better dispersed in CPE in comparison to natural MMT clay. Mechanical testing showed enhanced tensile strength, Young’s modulus, and storage modulus of chlorinated-polymers/organically treated MMT clay nanocomposites. Significant improvements in the above properties were obtained with Cloisite^® 15A nanoclay. The temperature, at which maximum degradation occurred, was higher for the nanocomposite having 5 wt% Cloisite 15A than that of neat CPE. Differential scanning calorimetric results revealed that the same composition also absorbed more heat during the heating, indicating better thermal stability. CPE rubber nanocomposite could be a promising heat resistant polymeric material.     

Synergy in carbon black-filled natural rubber nanocomposites. Part I: Mechanical,dynamic mechanical properties,and morphology

Synergistic effect of carbon black (CB) in presence of nanofillers (nanoclay and nanofiber) on mechanical and dynamic mechanical properties was discussed in light of electrostatic interactions and the concomitant microstructural developments, in Part I of this series. These interactions enhanced filler dispersion and ensured efficient stress transfer from the matrix resulting in improvement in properties, undiminished even by continual increase in CB loading. In this part, the micromechanical processes that influence wear behavior have been addressed conjointly with dynamic mechanical properties. Tribological characteristics were studied by sliding rubber wheel samples against a steel blade, in a specially designed abrader, in both transient and steady state conditions. Wear loss was reduced in the dual filler nanocomposites by 33% (over the CB microcomposite) in less stringent and 75% under severe wear conditions. These CB filled nanocomposites also illustrated lowering of coefficient of friction and temperature build-up. This was attributed to efficient heat dissipation due to the formation of a unique microstructural architecture by the participating fillers and also an adhering transfer film on the abraders’ counterface. From viscoelastic measurements, the CB filled nanocomposites were also found to lie in the high performance window of good wet skid and low rolling resistance.     

Synergy in carbon black filled natural rubber nanocomposites. Part II: Abrasion and viscoelasticity in tire like applications

Synergistic effect of carbon black (CB) in presence of nanofillers (nanoclay and nanofiber) on mechanical and dynamic mechanical properties was discussed in light of electrostatic interactions and the concomitant microstructural developments, in Part I of this series. These interactions enhanced filler dispersion and ensured efficient stress transfer from the matrix resulting in improvement in properties, undiminished even by continual increase in CB loading. In this part, the micromechanical processes that influence wear behavior have been addressed conjointly with dynamic mechanical properties. Tribological characteristics were studied by sliding rubber wheel samples against a steel blade, in a specially designed abrader, in both transient and steady state conditions. Wear loss was reduced in the dual filler nanocomposites by 33% (over the CB microcomposite) in less stringent and 75% under severe wear conditions. These CB filled nanocomposites also illustrated lowering of coefficient of friction and temperature build-up. This was attributed to efficient heat dissipation due to the formation of a unique microstructural architecture by the participating fillers and also an adhering transfer film on the abraders’ counterface. From viscoelastic measurements, the CB filled nanocomposites were also found to lie in the high performance window of good wet skid and low rolling resistance.     

Mercerization of sisal fibers: Effect of tension on mechanical properties of sisal fiber and fiber-reinforced composites

Sisal fibers were mercerized, under tension and no tension, to improve their tensile properties and interfacial adhesion with soy protein resin. Mercerization of fibers under tension is known to minimize fiber shrinkage and to lower the microfibrillar angle by aligning them along the fiber axis. Mercerization improved the fracture stress and Young’s modulus of the sisal fibers while their fracture strain and toughness decreased. Mercerized sisal fiber-reinforced composites with soy protein resin showed improvement in both fracture stress and stiffness by 12.2% and 36.2%, respectively, compared to the unmercerized fiber-reinforced composites. Scanning electron microscope (SEM) photomicrographs of the composite fracture surfaces showed shorter fibrils protruding in the mercerized fiber-reinforced composites resulting in better sisal fiber/soy adhesion. Changed fiber surface properties were also responsible for better adhesion.     

Mechanism of oxygen electrode delamination in solid oxide electrolyzer cells

An electrochemical model for degradation of solid oxide electrolyzer cells is presented. The model is based on concepts in local thermodynamic equilibrium in systems otherwise in global thermodynamic non-equilibrium. It is shown that electronic conduction   through the electrolyte, however small, must be taken into account for determining local oxygen chemical potential, μ_O2${\mu }_{{\mathrm{O}}_2}$, within the electrolyte. The μ_O2${\mu }_{{\mathrm{O}}_2}$ within the electrolyte may lie out of bounds in relation to values at the electrodes in the electrolyzer mode. Under certain conditions, high pressures can develop in the electrolyte just near the oxygen electrode/electrolyte interface, leading to oxygen electrode delamination. These predictions are in accord with the reported literature on the subject. Development of high pressures may be avoided by introducing some electronic conduction in the electrolyte.     

Optimum length of underground tunnel and corresponding annual heating/cooling potentials

Dimensionless optimum lengths of an underground tunnel, for which annual heating potential (HPD) and annual cooling potential (CPD) per unit tunnel length are maximum, have been obtained in terms of dimensionless parameters. The effect of different earth-surface treatments (shading, wetting, blackening and glazing) over the tunnel on the optimum tunnel length and corresponding values of HPD/CPD for three climates, namely hot-dry, composite and cold-dry, prevalent in the country have also been evaluated.