Studies on Egg Albumin Gelation Using Nuclear Magnetic Resonance

Pulsed nuclear magnetic resonance was used to monitor the thermophysical transition of aqueous egg albumin dispersion. Gelling, which was manifested by an increase in force required to penetrate the surface of the dispersion, was accompanied by a decrease in T₁, the spin-lattice relaxation time of water protons in the dispersion. There was a high, negative correlation coefficient between gel strength and T₁. Apparent rate kinetics of the transition was fist order for changes in T₁ and zero order for changes in gel strength, with activation energies for the rate constants of 42.62 and 43.68 kcal/mole, respectively.     

Call for Papers

Call for Papers

Call for Papers     

LARGE CRYSTALLINE GRAIN CdTe THIN FILMS FOR PHOTOVOLTAIC APPLICATION

A simple new method suitable to grow large crystalline grain CdTe thin films on glass substrates has been developed. CdTe films which exhibit a grain size larger than 20 µm have been obtained. The films are p-type with a resistivity of about 100 Ωcm. Backwall CdTe/CdS thin film solar cells with an efficiency above 9% have been prepared.     

A RESPONSE SURFACE METHODOLOGY APPROACH to OPTIMIZE POTATO DEHYDRATION PROCESS

A process for the production of high quality dehydrated potato cubes by high temperature fluidized bed (HTFB) initial drying followed by tunnel drying was optimized by response surface methodology. Drying temperature (T), exposure time in HTFB drier (t) and concentration of biopolymers (C) as pretreatment were determined as the most important factors affecting rehydration ratio, puffing, nonenzymatic browning and water holding capacity in the finished product. Optimum conditions for 0.95 cm potato cubes were: T = 145°C; t = 10 min; C = 1.2% and blanching time (b) = 4.5 min. Values predicted by the surface response model for rehydration ratio, bulk density, nonenzymatic browning and expressible fluid at the optimum were 5.75, 0.156, 0.20 and 4.8%, respectively. These values were experimentally varified and very close agreement between experimental and predicted values were obtained.     

Brining Procedures to Produce Uniform Salt Content in Fish

Inhibition of outgrowth and toxin production by Clostridium botulinum type E in smoked fish homogenates has been demonstrated at 3% water phase salt. Having the required salt content on a product that would not be too salty requires a uniform salt distribution throughout the fish. A two-stage brining procedure was developed that resulted in minimal differences in water phase salt contents between the thin and thick sections of a fish. The first stage involved soaking in 10% NaCl for 15 hr, using a fish to brine ratio of approximately 1 lb to IL. A second stage soak in 2% NaCl for 24–48 hr depending on the size of the fish leached out excessive salt in the thin sections of the fish while leaving the salt iinside the thick sections. Analysis of samples from four different areas on the smoked fish brined using the two stage procedure revealed a uniform salt content.     

KINETICS OF HEAT COAGULATION OF EGG ALBUMIN DETERMINED BY WATER BINDING AND RHEOLOGICAL MEASUREMENTS

Dynamic testing of heat coagulated egg albumin revealed that phase angle, a measure of the fluidity of a viscoelastic material, exhibits a first order change during heating in a similar manner as the changes in the spin-lattice relaxation time (T1) of water protons measured by a pulsed nuclear magnetic resonance instrument. The absolute modulus, on the other hand, which is an index of the elastic properties exhibited a zero order change in a similar manner as the development of gel strength measured by constant rate penetrometry using an Instron universal testing instrument. Arrhenius activation energy of 29 kcal/mole for the phase angle and 38.9 kcal/mole for the absolute modulus indicate that the process of protein-water interaction to immobilize water within the gel and that of protein-protein interaction to form the solid gel network occur simultaneously during heating, but they proceed by different mechanisms with the latter process showing greater heat sensitivity.     

Adaptive motion control design of robot manipulators: an input-output approach

An input-output approach to adaptive motion control design of robot manipulators is presented. The main technical device in our approach is the passivity theory. This formulation provides a framework suitable for the design of new control and adaptation laws. A new control law which consists of a computed torque part and a feedforward compensation part is analysed using this approach.