Reverse osmosis separations of polyethylene glycols in dilute aqueous solutions using porous cellulose acetate membranes

Reverse osmosis separations of eight polyethylene glycol (PEG) solutes in the average molecular weight range of 200 to 6750 in single-solute dilute aqueous solutions have been studied using porous cellulose acetate membranes at the operating pressures of 50, 75, and 100 psig. Diffusivity data for the above PEG solutes have also been obtained from experimental data on intrinsic viscosities. From an analysis of all experimental data, numerical values for the parameters representing the polar (?ΔΔG/RT), steric (δ^*ΣE_s), and nonpolar (ω^*Σs^*) forces governing reverse osmosis separations of PEG solutes have been generated. These numerical values are useful for precise characterization of cellulose acetate membranes for whose specifications sodium chloride is not the appropriate reference solute because of its low or practically negligible separation under reverse osmosis operating conditions. This work also illustrates that solute separation in reverse osmosis can predictably increase or decrease with increase in operating pressure depending on experimental conditions.     

An Image Processing Method for Quantifying Fiber Formation in Meat Analogs Under High Moisture Extrusion

High moisture extrusion using twin‐screw extruders shows great promise for producing meat analog products with vegetable proteins. The resulting products have well‐defined fiber formations and resemble real meat in both visual appearance and taste sensation. Developing reliable nondestructive techniques to quantify the textural properties of extrudates is important for quality control in the manufacturing process. In this study, we developed an image‐processing technique to automatically characterize sample fiber formation using digital imaging. The algorithm is based on statistical analysis of Hough transform. This objective method can be used as a standard method for evaluating other noninvasive methods. We have compared the fiber formation indices measured using this technique and a noninvasive fluorescence polarization method and obtained a high correlation.     

Water-blown rigid and flexible polyurethane foams containing epoxidized soybean oil triglycerides

Both rigid and flexible water-blown polyurethane foams were made by replacing 0–50% of Voranol® 490 for rigid foams and Voranol® 4701 for flexible foams in the B-side of foam formulation by epoxidized soybean oil. For rigid water-blown polyurethane foams, density, compressive strength, and thermal conductivity were measured. Although there were no significant changes in density, compressive strength decreased and thermal conductivity decreased first and then increased with increasing epoxidized soybean oil. For flexible water-blown polyurethane foams, density, 50% compression force deflection, 50% constant force deflection, and resilience of foams were measured. Density decreased first and then increased, no changes in 50% compression force deflection first and then increased, increasing 50% constant force deflection, and decreasing resilience with increase in epoxidized soybean oil. It appears that up to 20% of Voranol® 490 could be replaced by epoxidized soybean oil in rigid polyurethane foams. When replacing up to 20% of Voranol® 4701 by epoxidized soybean oil in flexible polyurethane foams, density and 50% compression deflection properties were similar or better than control, but resilience and 50% constant deflection compression properties were inferior. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Protein–Protein Interactions in High Moisture-Extruded Meat Analogs and Heat-Induced Soy Protein Gels

Two commercial soy protein isolates were made into fibrous meat analogs by high moisture extrusion or into gels by heating and cooling, at varying concentrations and/or temperatures. Protein–protein interactions by extrusion or gelation were investigated through protein solubility studies of raw and finished products. All samples except for extrudates exhibited similar patterns of solubility in four selected extractants. Phosphate buffer (PB) extracted the least amount of protein. Addition of dithiothreitol (DTT) to PB improved protein solubility, indicating the presence of disulfide bonds. PB + Urea and PB + Urea + DTT gave the highest and almost equal amount of extractable proteins from all samples, except for the extrudates from which protein could not be extracted effectively by PB + Urea, implying that disulfide bonding was more pronounced during extrusion than gelation. The results support our hypothesis that soy protein gels and extrudates both have the same types of chemical bonds, namely covalent disulfide bonds and non-covalent interactions. It is the relative proportion of each type of bonds in their structures that differentiates the two with respect to reversibility and structure rigidity. In forming protein gels during heat-induced gelation, non-covalent bonds play a dominant role over disulfide bonds; whereas for forming the fibrous structure of protein extrudates, non-covalent bonds and covalent disulfide bonds are both important.     

Physical Properties, Sensory Attributes, and Consumer Preference of Pear Fruit Leather

ABSTRACT: Pear fruit leathers were prepared by drying a mixture of pear juice concentrate, pectin, corn syrup, and water at 70°C for 8 h. The effects of ingredients on texture, color, microbial growth, moisture content (MC), water activity (a_w), glass transition temperature (T_g), and sensory attributes were investigated. Pectin was the most significant independent variable that affected the properties of interest. This was followed by initial moisture content and corn syrup. Glass transition temperature (T_g) was not useful for predicting microbiological attributes but had strong correlations with instrumental and sensory hardness and chewiness. The results from partial least squares analysis (PLS) indicate instrumental hardness, chewiness, and cohesiveness could be used to predict their corresponding sensory attributes. The consumer liking of pear fruit leather could be increased by raising their fruit aroma, sweetness, tartness, and shininess.     

The effect of rapeseed oil added to control grain dust on the quality of wheat

The effect of spraying edible rapeseed oil on controlling dust in barley, oat, rye and wheat has been investigated. Both the amount of rapeseed oil deposited and initial dust level govern the dust reduction level whereas the type of grain is immaterial. Regarless of the initial dust concentration, about 80% dust could be reduced with only 0.05% rapeseed oil addition. When the initial dust level exceeded 750 mg/m³, dust reduction could reach 90%. Although some dust adhered to the wheat kernels after rapeseed oil application, except for slight deteriorations in flour ash and color, other flour analytical properties, physical dough properties, and milling and baking qualities were unaffected. Paper no. 477 of the Canadian Grain Commission, Grain Research Laboratory, Winnipeg, Manitoba, Canada, R3C 3G9.