A group of Chinese scientists at The Chinese University of Hong Kong have discovered an alternative to plastic food packaging derived from soy protein isolate. According to the researchers, the biodegradable, transparent, and edible material is capable of replacing plastic food packaging and other non-degradable plastics.
The material was developed by working with bacterial cellulose (BC), an organic compound created out of various types of bacteria. It is proposed as a viable alternative due to its environmentally friendly synthesis process, non-toxic nature, and robust mechanical strength.
“This research serves as a reminder that natural raw materials may already possess the necessary characteristics to perform beyond the functions of plastic packaging.”
The corresponding author of the study Professor To Ngai further highlights its impressive tensile strength and high versatility.
“Extensive research has been conducted on BC, including its use in intelligent packaging, smart films, and functionalized materials created through blending, coating, and other techniques,” he told the Society of Chemical Industry. “These studies demonstrate the potential of BC as a replacement for single-use plastic packaging materials, making it a logical starting point for our research.”
BC is produced through microbial fermentation — which does not contribute to deforestation or habitat loss. This is due to a lack of a necessity to harvest trees or crops, ensuring a “more sustainable and environmentally friendly material alternative to plant cellulose”.
Eliminating the need for single-use packaging
BC has impressive tensile strength and versatility, making it a logical replacement for single-use plastic packaging materials. However, BC’s sensitivity to moisture has limited its widespread adoption.
The researchers describe an approach to incorporating soy proteins into the structure and coating it with an oil-resistant composite to create an edible, transparent, and robust BC-based composite packaging.
“The material developed in this research is completely edible, making it safe for turtles and other sea animals to consume without causing aquatic toxicity in the ocean,” Ngai added.
It is further shown to have full degradability within one to two months, with high tensile strength in both wet and dry conditions — outperforming more commercially available packaging such as kraft paper and low-density polyethylene.
Scaling up production is highly feasible, as well. “It does not require specific reaction conditions like chemical reactions, but rather a simple and practical method with mixing and coating,” Ngai explained.
The CUHK researchers are now aiming to improve the versatility of modified BC films, allowing them to be used in a wider range of applications. This process starts with developing a thermosetting adhesive that allows BC to be shaped into different forms after heating.
“One of the main challenges with bacterial cellulose films is that they are not thermoplastic, which limits their potential for use in certain applications,” Ngai said. “By addressing this issue, we hope to make bacterial cellulose films more competitive with traditional plastics while maintaining their eco-friendliness.
“This research serves as a reminder that natural raw materials may already possess the necessary characteristics to perform beyond the functions of plastic packaging.”
