Investigation on the preparation of pea protein based products

Pea protein products such as flour, concentrate and isolate are considered as functional food additive alternatives to soy protein. In this research pea protein concentrate and isolate were prepared from defatted pea flour by applying alkaline extraction and isoelectric precipitation. Chemical compositions (protein, fat, ash, fiber and water contents), functional properties (water and fat absorption, gelation, foaming capacity and foam stability), and thermal properties (glass transition and denaturation temperatures) of pea protein concentrate and isolate were determined and compared with the soy protein products. Then edible films were prepared from pea protein isolate. The effects of protein and glycerol concentrations on water vapor transmission rate (WVTR), mechanical properties, thickness, opacity and total color difference (¦¤E) of the films were evaluated, using response surface methodology (RSM). Protein content of concentrate and isolate obtained from defatted pea flour were 80% and 88.6%, respectively. The results showed that there were no significant differences in water and oil absorptions of soy and pea proteins. Gelation properties and foaming capacity of all protein products increased with the increase in concentration. However, soy protein had higher foaming capacity and foam stability compared to pea proteins (P΅ά0.01). Pea and soy protein isolates had semi-crystalline structures and soy protein showed higher thermal stability than pea protein. The results of pea protein based films revealed that WVTR, elongation, ¦¤E, thickness and opacity were increased, while tensile strength decreased by glycerol concentration. Increasing the concentration of protein increased tensile strength, opacity and ¦¤E, while decreased WVTR and elongation of the films. The model developed by RSM for the physical and mechanical properties of the films had high coefficient of multiple determination (R2 0.87) and significant F values.