Treatments of protein for biopolymer production in view of processability and physical properties: A review

Abstract

The development of bio-based polymers from proteins has gained attention for their large availability and renewable and biodegradable nature. However, protein-based plastics have limited commercial applications because of several drawbacks, such as poor processability, brittleness, moisture sensitivity, and inferior mechanical and thermal properties. Extensive studies have been conducted to solve or ameliorate these issues by pretreatment or modification of proteins or protein-derived biopolymers before or during wet processing or dry processing at elevated temperatures. This review provides an overview of research efforts conducted in the area of physical and chemical treatment of proteins to achieve better processability, mechanical properties, and other physical performance based on a literature review in this subject. INTRODUCTIONBiopolymers derived from agricultural resources such as wool, cotton, leather, and silk have been extensively used by humans for a long time. Industrial use of agricultural commodities for fuels and consumer products began in the 1920s. They were soon replaced by petroleum-based chemicals after World War II because these synthetic polymers were cheaper, more durable, and more versatile. Advances in petroleum-based fuels and polymers have benefited mankind in numerous ways. However, sustainability of their production and use has become a societal concern. Besides, petroleum resources are finite, and their prices are likely to continue to rise in the future. The disposal of petroleum-based plastic has also been causing environmental concerns. 1 Since the early 1990s, the use of renewable biopolymers as a substitute for nonbiodegradable petrochemical-based polymers has again attracted considerable attention because of their environmental benefits such as renewability and biodegradability. Nowadays, natural polymers can even be tailored to meet specific needs.Protein is one of three main categories of renewable biopolymers aside from polysaccharides and polynucleotides that are derived from plant or animal resources. Plant proteins that can be used for bio-based plastics include soy protein, corn zein, wheat protein, cottonseed protein, and sunflower protein. Animal proteins such as blood meal, gelatin and collagen, keratin and feather quills, egg protein, whey protein, and meat and bone meal can also be used as a feedstock for such bio-based polymers. 2 Despite their environmental friendliness, proteinbased biopolymers have many shortcomings like lower mechanical properties when compared to petroleum-based polymers. 3 Due to the hydrogen bonds between C@O and NH groups, protein-based polymers have poor processability and exhibit high sensitivity to moisture. As a result, the protein-based polymers are very difficult to process without plasticizers or pretreatment. To date, overcoming these shortcomings of proteinbased bioplastics has proven difficult. Numerous methods have been investigated, including physical treatment, denaturation of the original protein in crystalline form, cleava...

Preparation and Characterization of New Environmentally Friendly Starch-Cellulose Materials Modified with Casein or Gelatin for Agricultural Applications

“…However, synthetic materials have a negative impact on the environment, due to their long degradation time. Therefore, there is increasing interest in the design and production of novel biodegradable composites from renewable resources [1,2,3,4,5,6].…”

“…Casein was chosen due to its film–forming properties and broad range of applications in food, textiles, adhesives, etc. and gelatin due to its gelling properties and the possibility of sol in the gel, as well as for its wide applications in the food industry, photography and industry pharmaceuticals [5,6,7,21,22,23,24,25,26,27,28,29,30]. Next, cellulose-starch composites were obtained by modifying a commercially available cellulose coating using the starch films.…”

Overview of Protein‐Based Biopolymers for Biomedical Application

“…They are widely divided as polysaccharide, polypeptides, and polynucleotides, based on their monomeric unit . They are usually extracted from the living system or wastes through various chemical processes . The processing conditions significantly affect their physiochemical properties including the hierarchical assembly.…”

Fabrication and Characterization of Biodegradable Composites from Poly (Butylene Succinate-Co-Butylene Adipate) and Taihu Lake Blue Algae

“…However, its extensive application is limited due to the high cost compared to petroleum-based polymers. Another approach to forming biodegradable plastics is to blend low-cost macromolecules, such as protein [10,11] , starch [12,13] and natural fiber [14,15] with high performance biodegradable plastics. Several studies on the development of bio-based plastics derived from soy protein, wheat protein, corn zein, and sunflower protein have been conducted [10].…”

“…Another approach to forming biodegradable plastics is to blend low-cost macromolecules, such as protein [10,11] , starch [12,13] and natural fiber [14,15] with high performance biodegradable plastics. Several studies on the development of bio-based plastics derived from soy protein, wheat protein, corn zein, and sunflower protein have been conducted [10]. Soy protein, as a widely studied plant proteins, has attracted intensive research interest for fabricating bioplastic films and articles [10,16,17].…”