Determinations of nonprotein nitrogen content of cheese whey.

Nonprotein nitrogen in pooled sweet (Cheddar and Dagano) and acid (cottage) wheys was estimated by currently proposed dialysis and chemical precipitation methods. Kjeldahl nitrogen analyses of (a) membrane retentates after water dialysis, and (b) 12% trichloroacetic acid plus .2% phosphotungstic acid filtrates indicated that nonprotein nitrogen values vary significantly with the method of sample preparation. Membrane porosity influence nonprotein nitrogen values for molecular weight cut-offs of 3500, 6000 to 8000 and 12,000 to 14,000. Dialyzable nitrogen values with all membranes were lower than 12% trichloroacetic acid soluble nitrogen for both wheys and higher than the 12% trichloroacetic acid + .2% phosphotungstic acid soluble nitrogen for all but the 3500 molecular weight cut-off membrane. The dialyzable nonprotein nitrogen fraction was heterogeneous but more that 80% was less than 3500 in molecular weight.     

Predictive residual vector quantization [image coding]

This paper presents a new vector quantization technique called predictive residual vector quantization (PRVQ). It combines the concepts of predictive vector quantization (PVQ) and residual vector quantization (RVQ) to implement a high performance VQ scheme with low search complexity. The proposed PRVQ consists of a vector predictor, designed by a multilayer perceptron, and an RVQ that is designed by a multilayer competitive neural network. A major task in our proposed PRVQ design is the joint optimization of the vector predictor and the RVQ codebooks. In order to achieve this, a new design based on the neural network learning algorithm is introduced. This technique is basically a nonlinear constrained optimization where each constituent component of the PRVQ scheme is optimized by minimizing an appropriate stage error function with a constraint on the overall error. This technique makes use of a Lagrangian formulation and iteratively solves a Lagrangian error function to obtain a locally optimal solution. This approach is then compared to a jointly designed and a closed-loop design approach. In the jointly designed approach, the predictor and quantizers are jointly optimized by minimizing only the overall error. In the closed-loop design, however, a predictor is first implemented; then the stage quantizers are optimized for this predictor in a stage-by-stage fashion. Simulation results show that the proposed PRVQ scheme outperforms the equivalent RVQ (operating at the same bit rate) and the unconstrained VQ by 2 and 1.7 dB, respectively. Furthermore, the proposed PRVQ outperforms the PVQ in the rate-distortion sense with significantly lower codebook search complexity.     

Implication of Remote Sensing Data under GIS Environment for Appraisal of Irrigation System Performance

Water Resources Management - Poor irrigation management is a common issue of irrigated agriculture. Assessment of irrigation system performance is essential to improve the irrigation system, which...     

3D microstructure of supercritical fluid extrudates I: Melt rheology and microstructure formation

The influence of melt rheology and processing conditions on the expansion and 3D microstructure of biopolymeric foams produced by supercritical fluid extrusion (SCFX) were investigated. Starch-based SCFX extrudates with five whey protein isolate (WPI) concentrations (0–18 wt%) and four SC-CO₂ levels (0–0.75 wt%) were produced. Melt rheology was studied with an online slit die rheometer. The 3D microstructure of foams was determined using X-ray microtomography. The starch-based melt showed shear-thinning behavior, with a lower consistency coefficient and higher flow behavior index with the addition of SC-CO₂. Whey protein acted as a diluent, which resulted in reduced melt viscosity. SC-CO₂ increased the expansion of whey protein added starch-based extrudates. However, structural collapse was observed at the 0.75 wt% SC-CO₂ level during post-extrusion drying at 85 °C. The cross-sectional expansion ratio of SCFX extrudates decreased by 48.9% with the addition of 18 wt% WPI. The cell number densities per unit volume and average cell size of SCFX extrudates were 1.4 × 10³–1.9 × 10⁴ cells/cm³ and 310.0–724.4 μm, respectively, depending on WPI and SC-CO₂ levels. A decrease in melt viscosity due to the addition of whey protein might be responsible for the lower cell number density and related decrease in expansion. Processing parameters and whey protein levels were critical to controlling the microstructure of starch-based SCFX extrudates.     

3D Microstructure of supercritical fluid extrudates. II: Cell anisotropy and the mechanical properties

The mechanical properties of biopolymeric cellular foams are often governed by their microstructure. 2D and 3D microstructural data of supercritical fluid extrudates were obtained with X-ray microtomography and correlated with the mechanical properties determined using compression and three-point bending tests. Cell size from transverse cross-sections of SCFX extrudates decreased with radial distance from the center. In the longitudinal direction, the cell shapes were more elliptical than spherical and were aligned along the extrusion direction. These findings indicated the presence of a certain degree of anisotropy in SCFX extrudates in both directions. Both piece density and the ratio of cell wall thickness to cell diameter were observed to be good predictors of compressive and flexural mechanical properties, including jaggedness parameters. Compressive modulus data suggested that cell shape anisotropy due to cell elongation in the longitudinal direction actually affected the mechanical properties of SCFX extrudates. X-ray microtomography was found to be useful to investigate 2D and 3D morphology of SCFX extrudates, including cell shape and cell size anisotropy.     

Hearing loss from hemodialysis

A 47-year-old man with normal hearing had chronic progressive renal failure. He experienced hearing loss in additive increments with peritoneal dialysis and hemodialysis, until he was profoundly deaf in both ears. Postmortem studies showed collapse of the endolymphatic system and edema and atrophy of most of the specialized cell types of the auditory and vestibular sense organs. It is our interpretation that the alterations were caused by osmotic disequilibrium associated with hemodialysis.     

HDPE reinforced with glass fibers: Rheology,tensile properties,stress relaxation,and orientation of fibers

Glass fiber‐reinforced high‐density polyethylene of varying concentrations was mixed with ethylene copolymer and maleic anhydride‐grafted polypropylene (coupling agents) separately. The viscosity, tensile strength, and stress relaxation properties of the composites were investigated. The orientation and anisotropy of glass fibers were studied using micro computed tomography scanner. It was found out that the orientation and anisotropy of fiber are strongly affected by the increase in glass fiber concentration. POLYM. COMPOS., 35:2159–2169, 2014. © 2014 Society of Plastics Engineers     

Emulsification mechanisms and characterizations of cold, gel-like emulsions produced from texturized whey protein concentrate

A novel supercritical fluid extrusion (SCFX) process was used to successfully texturize whey protein concentrate (WPC) into a product with cold-setting gel characteristics that was stable over a wide range of temperature. It was further hypothesized that incorporation of texturized WPC (tWPC) within an aqueous phase could improve emulsion stability and enhance the rheological properties of cold, gel-like emulsions. The emulsifying activity and emulsion stability indices of tWPC and its ability to prevent coalescence of oil-in-water (o/w) emulsions were evaluated and compared with the commercial WPC80. The cold, gel-like emulsions were prepared at different oil fractions (φ = 0.20–0.80) by mixing oil with the 20% (w/w) tWPC dispersion at 25 °C and evaluated using a range of rheological techniques. Microscopic structure of cold, gel-like emulsions was also observed by Confocal Laser Scanning Microscope (CLSM). The results revealed that the tWPC showed excellent emulsifying properties compared to the commercial WPC in slowing down emulsion breaking mechanisms such as creaming and coalescence. Very stable with finely dispersed fat droplets, and homogeneous o/w gel-like emulsions could be produced. Steady shear viscosity and complex viscosity were well correlated using the generalized Cox–Merz rule. Emulsions with higher viscosity and elasticity were obtained by raising the oil fraction. Only 4% (w/w) tWPC was needed to emulsify 80% (w/w) oil with long-term storage stability. The emulsion products showed a higher thermal stability upon heating to 85 °C and could be used as an alternative to concentrated o/w emulsions and in food formulations containing heat-sensitive ingredients.     

High carbon-di-oxide modified atmospheric packaging on quality of ready-to-eat minimally processed fresh-cut iceberg lettuce

Fresh-cut lettuce is a very well-known salad for today''s routines because it obliges minimal preparation to minimize the loss of health beneficial vitamins, minerals, antioxidants and other phytochemicals. It is a prodigious challenge to serve its consumers fresh. Quality of freshly processed lettuce under high CO₂ modified atmosphere packaging (MAP) has been investigated as a realistic alternative technique for its preservation. Storage under high CO₂ atmospheric treatments exhibited a significant impact in microbial development, electrolyte leakage, volatile metabolites and sensory quality of fresh-cut iceberg lettuce. This storage condition (MAP 1: 5 kPa O₂ and 20 kPa CO₂ balanced by N₂ at 7 °C for 6 days) inhibited the growth of mesophilic bacteria and yeasts; delayed the enzymatic browning (cut-edges and intact surface) of fresh-cut iceberg lettuce and overall visual quality was also in acceptance limit. The development of off-odors was perceived in high CO₂ MAP as a consequence of volatiles (ethanol and acetaldehyde) accumulation which was persisted at an inexcusable level during 6 days of storage periods.