University of Queensland researchers have used natural tree sap gum and light to extend the shelf life of fresh fruit and vegetables in an effort to reduce food waste.
The Queensland Alliance for Agriculture and Food Innovation (QAAFI) research focused on edible coatings made from gum Arabic, or acacia gum, infused with aqueous extracts from native Australian plants. The aim was to inhibit the growth of microorganisms that cause spoilage.
The team also explored using light and curcumin, a compound from turmeric, to deactivate fungal spores, particularly on strawberries.
QAAFI’s Dr Maral Seididamyeh said the methods proved effective in prolonging food freshness.
“Using our edible coating, we were able to prevent the growth of spoilage microorganisms in fresh-cut capsicum for around 10 days in the fridge,” Dr Seididamyeh said.
“This was mainly 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.
“These extracts not only showed promising antimicrobial properties, but sensory analysis also showed they enhanced the overall sensory attributes.”
“The curcumin-based photosensitisation technique completely deactivated fungal spores of Botrytis cinerea – the pathogen responsible for grey mould in fresh produce.
“When applied to strawberries, it reduced decay incidence and severity by 20 per cent without compromising the fruit’s colour or firmness.”
Dr Seididamyeh said chemical-free methods for preventing food spoilage were in demand.
“Bacteria, viruses, fungi and parasites are becoming resistant to synthetic chemicals used to preserve food,” she said.
“At the same time, consumers are increasingly favouring products made with natural preservatives over synthetic additives, known as the clean label trend.”
Data from the Food and Agriculture Organisation of the United Nations shows 17 per cent of food is lost to spoilage and other issues at retail outlets and in homes.
“The research results are promising, but more work is needed, especially since photosensitisation is a relatively new concept in the food industry,” said Dr Seididamyeh.
“Photosensitisation is already used in medicine, through photodynamic therapy, which destroys abnormal cells in cancer and precancerous conditions.
“But both the edible gum coating, embedded with extracts from native Australian foods and leaves, and curcumin are currently quite expensive.
“To make this a mainstream solution, further funding is needed to refine the technology for integration into commercial packing and processing lines.”
The research was funded by Hort Innovation, the Department of Primary Industries, and the Australian Research Council.
The study was published in the Journal of Food Science, Food Control and Foods, and the International Journal of Biological Macromolecules.