Stellies study suggests safer way to package food
A DOCTORAL study has revealed that wheat straw and mango peels, which are usually disposed of in landfills or used for manure and animal feed, could potentially be used in the development of renewable, biodegradable and non-toxic active food packaging.
Stellenbosch University said yesterday this finding would allow it to assist in keeping products fresher for longer.
Dr Lindleen Mugwagwa, who recently obtained her doctorate in chemical engineering and is a post-doctoral fellow in the Department of Process Engineering, said there was a move towards renewable and biodegradable food packaging to replace non-renewable and non-biodegradable petroleum-based packaging materials.
She said agricultural residues, such as wheat straw and mango peels, which are rich in bio or natural polymers and antioxidants, could be used as alternative raw materials.
According to the university, Mugwagwa’s study was the first to develop methods of extracting the necessary bio or natural polymers and antioxidants from both wheat straw and mango peels that contain properties that are suitable for developing an active food packaging material.
“It was also the first time that these products were integrated to form a bio-composite film (a material composite consisting of biodegradable polymers and bio-based reinforcing agents) that was tested in a food environment,” it said.
Mugwagwa has managed to develop and optimise processes for extracting the polymers and antioxidants.
She has combined the polymers and antioxidants to make a food-packaging material and has tested the stability of the bio-composite films when in contact with food, as well as their potential to release antioxidants into packaged food over time.
Mugwagwa used a low-density polyethylene film (a commonly used plastic) as a benchmark.
She said her study showed that the wheat straw and mango peels’ properties of polymers and antioxidants could be tailor-made during the extraction process in order to suit their application in food packaging.
The polymers and antioxidants could be extracted simultaneously without affecting their use in food packaging.
“The bio-based films that I developed were capable of releasing more antioxidants into food over a short period of time when compared to low-density polyethylene plastic. This suggests that they can be a replacement for packaging perishables ,” said Mugwagwa.
She said the release of antioxidants into food by packaging material was becoming an important aspect to consider when choosing package material.
She added that packaging material capable of releasing antioxidants into food in response to storage conditions has the potential to prolong the shelf life of products.
“My research provides cheap, sustainable and biodegradable polymers that can be used in the development of food packaging, and also presents methods for recovering natural antioxidants and their application as additives to food-packaging material.
“These natural antioxidants have the potential to replace artificial antioxidants in packaging material that could cause cancer,” Mugwagwa said.
She said biorefineries, the foodpacking industry, farmers and consumers would all benefit from her research.
The bio-based films I developed were capable of releasing more antioxidants into food over a short period of time
DR LINDLEEN MUGWAGWA department of process engineering