Thermoplastic films from plant proteins

Authors

  • Narendra Reddy,

    1. Department of Textiles, Merchandising and Fashion Design, University of Nebraska-Lincoln, Lincoln, Nebraska
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  • Yiqi Yang

    Corresponding author
    1. Department of Textiles, Merchandising and Fashion Design, University of Nebraska-Lincoln, Lincoln, Nebraska
    2. Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
    3. Nebraska Center for Materials and Nanoscience, 234, HECO Building, East Campus, University of Nebraska-Lincoln, Lincoln, Nebraska
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ABSTRACT

Films developed by thermoprocessing of plant proteins have better mechanical properties and are relatively inexpensive and environmentally friendly compared to casting films from solutions. Common plant proteins such as soyproteins, wheat gluten, and corn zein and proteins from lesser grown cereal crops such as peanut, barley, sunflower, and sorghum have all been injection or compression molded into films. Since plant proteins are non-thermoplastic, it is necessary to chemically or physically modify the proteins and make them thermoplastic. Extensive studies on the addition of plasticizers, pre-treatment of proteins with alkali, steam, chemical modifications such as acetylation and blending of the proteins with other biopolymers and synthetic polymers have been done to modify proteins and develop thermoplastics. Despite the extensive work, thermoplastic films obtained from plant proteins do not have the properties that can meet or exceed properties of films made from synthetic polymers. Poor water stability and brittleness are the two major limitations of plant protein films. This review presents an overview of the methods and processing conditions used to develop thermoplastic films from plant proteins and the properties of the films. A critical assessment of approaches that have been used so far, limitations of these approaches and potential considerations for future studies to overcome the current limitations have been discussed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 729-738, 2013

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