Researchers at the Indian Institute of Technology (IIT), Guwahati have developed an edible and biodegradable coating to extend the shelf-life of fruits and vegetables.

As per officials, this coating material was tested on vegetables such as potato, tomato, green chili, strawberries, Khasi Mandarin variety of orange, apples, pineapples and Kiwi; and was discovered that these vegetables remained fresh for almost two months.

The outcomes of this 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.

Meanwhile, researchers believed that their development could help the country meet the Sustainable Development Goal (SDG) target 12.3, which aims to reduce 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,” – informed the Professor at Department of Chemical Engineering – Vimal Katiyar.

In order to create protective, edible films for coating on plants and fruits, the scientists combined a micro-algae extract with polysaccharides. The marine microalga Dunaliella tertiolecta has a number of bioactive substances, including carotenoids, proteins, and polysaccharides, and is well known for its antioxidant qualities.

“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,” – he added.

The manufactured edible films showed exceptional antioxidant activity, total phenolic content, water vapour barrier performance, thermal stability, and mechanical strength. Additionally, they were effective UV-Vis light-blockers.

Based on the requirement, numerous customized edible coating formulas are also created to lengthen the shelf-life of produce.

“We also tested the biosafety of these coatings by treating BHK-21 cells with these coating materials. BHK-21 cells are derived from the kidneys of baby hamsters and are used for studying the toxicity effects of various materials. Their tests showed that these coating materials were nontoxic and could be safely used as edible food packaging materials. The newly-developed coatings can be mass-produced and are unique. They are very stable to light, heat and temperature up to 40 degrees Celsius, edible and can be safely eaten as part of the product formulation and do not add unfavourable properties to it. They retain the texture, colour, appearance, flavour, nutritional value and microbial safety of the fruit or vegetable that has been coated, thereby enhancing their shelf life to several weeks to months,” – Katiyar further remarked.