Comparison of chickpea and soy protein isolate and whole flour as biodegradable plastics

The objective of the present work is to compare some different crop products such as protein isolates and defatted whole flours from legumes, as chickpea and soy bean, involved in the molded compression processing to obtain plastics. The present work analysed the possibility of forming new plastic materials with products of chickpea, and soy bean seeds typically from the North West of Argentina, conditioned as chickpea isolate (CI), chickpea whole flour (CWF) in relation with soy protein isolate (SI) and soy whole flour (SWF). The blends containing isolates or defatted whole flour of chickpea, with the addition of glucopolysaccharide, glycerol and water as plasticizers were compression molded at 120°C, at 20 MPa, for 7 min. The glucopolysaccharide employed from this vegetals presented a ratio of amylose to amylopectin structure 95/5. The molded specimens were calculated for their tensile strength, percent elongation at break and water absorption. The chickpea isolate would be important in the production of plastic materials because of the best mechanical properties and the smallest water absorption. The chickpea whole flour product gave better material than soy whole flour product, even if the mechanical properties of both are lower than chickpea and soy isolates, respectively. Addition of boric acid in the blend induced a fall in water absorption in the case of soy plastics, but was not important in chickpea plastics. The effect of irradiation was to decrease water absorption in soy plastics and chickpea whole flour, while the effect on mechanical properties was not important. © 2000 Elsevier Science B.V. All rights reserved.