Researchers at Indian Institute of Technology (IIT) in Guwahati have developed an edible and biodegradable coating for fruits and vegetables that extend their shelf-life.

According to reports, the coating material was tested on vegetables such as potato, tomato, green chili, strawberries, Khasi Mandarin variety of orange, apples, pineapples and Kiwi. It was found that the material keeps these vegetables fresh for nearly two months.

The results of the research have been published in noted journals including Royal Society of Chemistry Advances; Food Packaging and shelf life and American Chemical Society’s Food Science and Technology.

With their development, the researchers believe it could help the country meet the Sustainable Development Goal (SDG) target 12.3 that is aimed at reducing food losses along the production and supply chains, including post-harvest losses.

“According to the Indian Council of Agricultural Research, between 4.6 and 15.9 per cent of fruits and vegetables go waste post-harvest, partly due to poor storage conditions. In fact, post-harvest loss in certain produce items like potato, onion and tomato which could be as high as 19 per cent, which results in high prices for this highly consumed commodity,” Vimal Katiyar, Professor at Department of Chemical Engineering, IIT Guwahati.

The team used a mix of a micro-algae extract and polysaccharides to produce protective, edible films for coating on vegetables and fruits.

The marine microalgae called Dunaliella tertiolecta is known for its antioxidant properties and has various bioactive compounds such as carotenoids, proteins, and polysaccharides.

“It is also used as a source of algal oil, which is used as a non-animal source of omega-3 fatty acid, and is being considered as a source of biofuel. After the oil is extracted, the residue is usually discarded. The researchers used extracts from this residue in formulating their film, in combination with chitosan.

“Chitosan, a carbohydrate, also has antimicrobial and antifungal properties and can be made into edible film. The properties of films with varying algal extract contents were analysed and compared with controls,” Katiyar said.

The fabricated edible films displayed a superior antioxidant activity, total phenolic content, water vapour barrier property, thermal stability, and mechanical strength. They also had excellent UV-Vis light-blocking property.