Researchers from the National University of Singapore have developed an environmentally friendly food packaging material by fortifying natural chitosan-based composite film with grapefruit-seed extract (GFSE).
Free from chemical additives, this novel food packaging material can slow fungal growth, doubling the shelf-life of perishable food such as bread.
Chitosan, a natural and biodegradable polymer derived from the shells of shrimp and other crustaceans, has immense potential for applications in food technology, owing to its biocompatibility, non-toxicity, short-time biodegradability and excellent film-forming ability. Chitosan also has inherent antimicrobial and antifungal properties. An antioxidant, GFSE possesses strong antiseptic, germicidal, anti-bacterial, fungicidal and anti-viral properties.
Associate Professor Thian Eng San and doctoral student Ms Tan Yi Min from the department of mechanical engineering at NUS spent three years perfecting composite film that not only prevents the growth of fungi and bacteria, but has mechanical strength and flexibility comparable to synthetic polyethylene film commonly used for food packaging. The composite film also effectively blocks ultraviolet light, hence slowing the degradation of food products from oxidation and photochemical deterioration reactions.
Bread samples packaged with chitosan-based GFSE composite films had a shelf life twice as long as those packaged using synthetic packaging films, according to laboratory experiments.
"Increasing attention has been placed on the development of food packaging material with antimicrobial and antifungal properties, in order to improve food safety, extend shelf-life and to minimize the use of chemical preservatives," Thian said. "Consumers are also demanding that packaging materials be formulated from natural materials that are environmentally friendly and biodegradable while improving food preservation. This novel food packaging material that we have developed has the potential to be a useful material in food technology."
The research received support from the A*STAR Singapore Institute of Manufacturing and Technology and the Food Innovation & Resource Centre of Singapore.
To improve on this technology, Thian and Tan plan to look into the degradability of chitosan-based GFSE films, and carry out an accelerated shelf-life study to examine the extent of microbial growth and quality changes during storage of various food products. There are also plans to explore opportunities to commercialize the composite film as a packaging material.