New Delhi: Indian scientists have developed a protective coating for fruits and vegetables in a crucial step towards combating food wastage.
A team from IIT, Guwahati have grown a biodegradable and edible layer – through a simple dip-coating technique — that will extend the shelf life of perishables, they said.
The coating has been tested on vegetables such as potatoes, tomatoes, green chilies, Khasi mandarin, apples, and strawberries. The method will add no significant cost to the post-harvest processing, researchers said.
The team was led by Professor Vimal Katiyar, from the Department of Chemical Engineering and Center for Excellence in Sustainable Polymers (CoE-SusPol), and Professor Vaibhav V. Goud, of the Department of Chemical Engineering, and CoE-SusPol, IIT Guwahati.
The results of their research have been published in the Royal Society of Chemistry Advances — the article showcases the effect of the coating on tomatoes — and the American Chemical Society’s Food Science and Technology, where authors talk about the general efficacy of the coating.
Katiyar said in a media release: “According to the Indian Council of Agricultural Research, between 4.6 and 15.9% 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 could be as high as 19%, which results in high prices for this highly consumed commodity.”
The coating is made primarily from micro-algae extract, researchers said, adding it could be directly coated on the vegetable or even morphed into a vegetable storage pouch.
To create the covering, a crude algae ethanolic extract was obtained from the waste de-oil green algae biomass or Dunaliella tertiolecta. This was sourced from The Energy and Resources Institute (TERI), India.
These algae are usually found in saline environments and can also be grown easily. Known for its antioxidant properties, it was used to create the edible film.
This is the first study on the development of an active edible food-packaging material with the Dunaliella tertiolecta green algae biomass extract, researchers said.
They combined the extract with Chitosan, a carbohydrate obtained from the deacetylation of chitin, found in crustaceans and insects, which possesses antimicrobial and antifungal properties. Previously, there has been limited use of Chitosan in food packaging owing to its poor barrier and mechanical properties.
The biosafety of these coatings was proven to be non-toxic and, therefore, suitable for edible packaging. Katiyar said in the press note, “The coatings can be mass-produced and safely eaten as they do not add any unfavourable properties. They retain the texture, color, appearance, flavor, nutritional value of the food items, and also enhance their shelf life to several weeks or months.”
During experiments, the edible films displayed the film had antioxidant properties (preventing reaction with oxygen-like gases) that protected the fruit for a longer period from naturally occurring cell damage. Moreover, the films also exhibited mechanical strength, and stability to light, heat, and temperature up to 40 degrees centigrade, water-vapour barrier and UV-Vis light-blocking properties.
Its biosafety was tested by treating BHK-21 cells, a standard protocol for testing toxicity and biocompatibility where the cells are obtained from the kidneys of baby hamsters and are used to analyse the toxicity of various materials. The tests revealed the coatings were completely non-toxic.
“Field trials with farmers have also begun by investigators in order to scale the product for mass use,” Professor Katiyar told ThePrint.
He added: “An IIT Guwahati-based start-up ‘Biojagat Private Limited’ is also working on the commercialisation of the developed formulations. However, it still needs to be further leveraged to other companies.”
The professor, who has worked on this project for the last six years, also said: “The constituents are biopolymers which we use in our day-to-day lives. The coating is also inexpensive as we use a very minimal amount of polymer in it.”
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