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A nondestructive imaging technique to quantify fibrous structures in soy protein extrudates is developed. The spatial distribution of light reflectance on sample surface was imaged and a fiber formation index was derived based on the random-walk theory of light transport in anisotropic media.

A new study investigates the effect of process conditions on the sensory and physical properties of extruded oat-corn puffs.

Research into the extrusion of soy protein meat analog.

Soy protein isolate (SPI) addition does not affect the hardness of low-fat sausage products, according to research designed to develop an innovative way of reducing fat in pork through extrusion technology. Springiness of sausages generally rose with a rise in extrusion temperature, but SPI did not have an impact on springiness. Higher fat reductions took place at high extrusion temperature treatments. This may have produced more springy and cohesive sausages.

Glass transition temperatures of yellow and white corn cakes were examined within the moisture range of 2 to 12% by employing dynamic differential scanning calorimetry. The consequences of water plasticization on corn cakes were computed through Gordon-Taylor's equation. The crispness of the corn cakes was observed in the glassy state. The loss of crispness started around monolayer moisture content and the complete loss of crispness was at about 9% moisture with the highest hardness.

Analysis of the surface images of corn puffs extruded under different processing conditions using image processing techniques reveals that image features in color and surface texture are efficient for effective differentiation and quantitative characterization of corn puffs resulting from different processing conditions. Surface texture details can be better derived from hue function than from saturation or intensity functions.

An APV Baker twin-screw extruder helps examine the influence of a barrel-valve assembly on extrusion system dynamics and product properties having different screw speeds and specific feeding loads (SFL). Change of barrel-valve from open to closed position induces a convex response of die pressure, system responses and extrudate properties. Change of product properties due to variations in SFL is higher than the variations in barrel-valve control.

Long-grain and medium-grain brown rice were used to study the puffing of rice cakes. An investigation of the effects of tempering moisture, heating temperatures and heating time on various rice cake quality attributes was carried out. When the tempering moisture was low, the heating temperature was high and the heating time was longer, then rice cakes made from long-grain brown rice had a greater specific cake volume. A higher tempering moisture yielded a larger specific cake volume for medium-grain rice. It was found that the less-expanded rice cakes were lighter in color and that medium-grain rice cakes were more fragile than long-grain rice cakes.

A study to determine the effects of changes in screw speed on the temperature, pressure, product characteristics and other variables involved in the extrusion process is presented. A twin-screw extruder was used in evaluating how step changes in screw speed affects product temperature, torque and mass pressure. Results showed that changes in screw speed had significant effects on the entire extrusion process. Unchanging dynamic responses were noted for greater step inputs while unstable responses were noted for small inputs, thus the variance in product characteristics.

The thermal properties, specific heat and thermal conductivity of extruded beef/corn meal blends were examined. The densities of the extruded products ranged from 1,054 to 1, 091 kg/m (super 3). Their specific heats were found to be from 2.944 to 3.055 kJ/kgk while thermal conductivity was measured to be 0.26 to 0.39 W/mK. Extrusion conditions and formulations, but not specific heat, were shown to affect some of the physical and thermal properties of the extruded products.

A study is conducted to develop a noninvasive method based on fluorescence polarization spectroscopy in order to measure the degree of fiber formation of extruded meat analogs. The texture profile analysis is found inadequate to describe the fiber formation whereas the visual inspection and digital imaging results of the dissected samples is found in good agreement with the new method.

Extrusion moisture content of soy protein isolate and wheat starch is analyzed. Comparative analysis of extrusion moisture, cooking temperature, and product sensory features of soy protein meat is studied.