Edible coatings keep fruit fresh for longer

A research team led by the University of Queensland has developed a way to combat food waste by slowing food spoilage — without the use of chemicals.

Data from the Food and Agriculture Organization of the United Nations has revealed that 17% of food is lost in retail outlets and homes as a result of spoilage and other issues.

To address this issue, the Queensland Alliance for Agriculture and Food Innovation (QAAFI) created edible coatings made from gum Arabic or acacia gum enriched with extracts from native Australian plants to stop the growth of spoilage-causing microorganisms. The team also used light and curcumin, a compound extracted from turmeric, to deactivate fungal spores on food.

Both methods were effective in keeping food fresh for longer, according to QAAFI’s Dr Maral Seididamyeh.

“Using our edible coating, we were able to prevent the growth of spoilage microorganisms in freshly cut capsicum for around 10 days in the fridge,” Seididamyeh said.

“This was mostly due to the organic acids and phenolic compounds found in the aqueous extracts of plants like Cape York lilly pilly, boonjee tamarind and Tasmanian pepper leaves.”

Seididamyeh said the extracts showed promising antimicrobial properties, with sensory analysis revealing that the fruit looked and smelt better.

“The curcumin-based photosensitisation technique completely deactivated the fungal spores responsible for grey mould in fresh produce.

“When applied to strawberries, it reduced decay incidence and severity by 20% without compromising the fruit’s colour or firmness.”

Seididamyeh said chemical-free methods for preventing food spoilage were in demand, as bacteria, viruses, fungi and parasites are becoming resistant to synthetic chemicals used to preserve food.

“Consumers are increasingly favouring products made with natural preservatives over synthetic additives,” she said.

While the research results are promising, Seididamyeh said more work is needed, especially since photosensitisation is a relatively new concept in the food industry.

“Photosensitisation is already used in medicine through photodynamic therapy to destroy abnormal cells in treatment for cancer and precancerous conditions,” Seididamyeh said.

“The edible gum coating, embedded with extracts from native Australian foods and leaves, and curcumin are currently quite expensive.

“To help make this a mainstream solution further funding will be needed to refine the technology for its integration into commercial packing and processing lines.”

The research was funded by Hort Innovation, the Department of Primary Industries and the Australian Research Council. Its findings have been published in the Journal of Food Science, Food Control and Foods, and the International Journal of Biological Macromolecules.

Image credit: iStock.com/MEDITERRANEAN