The Benefits of Biomaterials for Food Packaging and More

In September 2011, the U.S. Dept. of Agriculture issued a report to Congress that addressed bioeconomy indicators. From biochemicals and biomaterials, biofertilizers, biofuels and bioenergy, biocides and bioceuticals to biomedicines, the spectrum of bio-based products, produced by more than 2,100 manufacturers, exceeds 15,000 items that are currently used by consumers in the United States (Iowa State, 2009).

Consumers in Western societies such as the United States and Europe desire to decrease their exposure to polymers derived from petrochemicals since they are often considered to be environmentally unacceptable and socially irresponsible. In the realm of bioeconomy, there is considerable research into the naturally occurring polymers that provide the same or similar physical  properties as their predecessors such as polyethylene terephthalate (PET) and low-density polyethylene (LDPE) yet may be more energy efficient and  biologically degradable (Mecking, 2004).

Recent research indicates that various microbes, through the fermentation of various carbohydrates, produce polyhydroxy-alkanoates (PHAs),  polyhydroxy-butyrate (PHBs), and similar compounds (Sudesh et al., 2000). These natural substances are produced under controlled conditions, and represent some of the bioplastics produced by environmentally friendly microbes. These materials may replace traditional materials derived from petrochemistry.

While the commercial production of these materials is not economical at this time, the biodegradable properties make applications of bacterial synthesized PHAs and PHBs quite attractive. Some of the applications include the  production of food coatings and packaging materials, utilization of food  production effluent, intracellular medication delivery, and even prosthetic medical devices, tissue structure, and implants (Vijayendra and Shamala, 2013; Koutinas et al., 2014; Lu et al., 2014; Bae et al., 2014; Peter and Kumar, 2013; Wu et al., 2014; Barua et al., 2014).

As the gluten-free food market continues to grow based on consumers’ perception of improved health and weight loss (Mintel, 2013), we are reminded that gluten that is found in wheat, rye, and barley is a part of plant storage proteins. From a food science perspective, the unique physical and chemical properties of gluten present some interesting viscoelastic characteristics for nonfood applications (Lagrain et al., 2010). Some of those applications are found in biocomposites that are products of high pressure and heat treatment. Through a wet process that is based on the dispersion and solubilization of proteins, wheat gluten-based films are produced that vary in their vapor resistance and tensile strength. However, this process remains  expensive and inefficient. Through a dry process, which relies on the  thermoplastic properties of proteins, wheat gluten may be converted and shaped to everyday materials similar to polypropylene and an array of  biopolymers (Pallos et al., 2006).

Despite these interesting results and applications, it is important to note that the mechanical properties of gluten-based materials differ considerably from  traditional rubbery products. However, from a positive perspective, these  materials represent potentially renewable resources for biodegradable materials (Jansens et al., 2013). An improved understanding of polymerization  processes, molecular architecture, and thermoplastic properties may contribute to more acceptable mechanical properties of gluten-derived materials.

The concepts and applications of edible and biodegradable protein-based  polymer films and coatings are not new. All living organisms, including microbes, plants, and animals, produce a spectrum of proteinaceous polymers that provide structural scaffolds and biological activity. Proteins from these  sources, under the appropriate processing conditions (e.g., temperature, pressure, moisture) can transform and heretofore would have been considered waste to practical products. Wheat gluten blends, corn meal, and soy protein  have many desirable thermoplastic characteristics that enable them to be formed and molded into edible films. These films may be used for food wraps and an array of packaging materials (Hernandez-Izquierdo & Krochta, 2008).

From a food safety perspective, these kinds of films, such as those from  chitosan and casein, have antimicrobial properties (Moreira et al., 2011a). For  example, limited research indicates these kinds of films may reduce spoilage of carrots, cheese, and salami, and thus provide alternatives to the more traditional packaging materials. Equally important, they appear to maintain the sensory quality of the vegetables while extending the shelf life (Moreira et al.,  2011b).

Applications of biomaterials will have significant impact on the safety and  quality of the food supply and on reducing some costs associated with  healthcare, including innovative technologies and diagnostic tools (Bhat & Kumar, 2013).

Roger Clemens, Dr. P.H., CFS,
Contributing Editor
Chief Scientific Officer,
Horn Company, La Mirada, Calif.
[email protected]