Abstract
Edible films made from peanut and soybean were developed using casting and single-screw extrusion methods. The effect of time, formulation and processing method on the rheological, barrier and physical properties of the experimental films were investigated. Rheological properties of selected commercial films were evaluated for the purpose of comparison. Stress relaxation technique (tension) allowed characterization of the rheological behavior of the experimental and evaluated films. Experimental data were fitted to 3,5 and 7-parameter Maxwell model as well as the Peleg and Normand's model. A five-parameter Maxwell model provided the best description of the stress relaxation behavior of all evaluated films. Stiffness and energy dissipated were calculated and used to detect the change on textural properties of the films. Cast and extruded films showed significant differences in strength, color and structural changes with time. Evaluation of barrier properties (water vapor permeability) of the cast films showed the potential of the peanut protein as a moisture barrier. Stiffness was selected to predict mechanical strength of the films. Mathematical models were built to predict the stiffness of the cast films as a function of soy protein isolate content. Stiffness of the extruded films exhibited a high correlation with peanut flour percentage in the formulation.
Tellez Garay, Angela Maria (1999). Characterization of peanut-soybean films for food packaging applications. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1999 -THESIS -T44.