Group led by Bangladeshi scientist develops edible coating: Fruits, veggies to last longer

Led by a Bangladeshi scientist, a group of researchers at Rice University in Texas developed a way to enhance the shelf life of fruits and vegetables using an entirely edible and washable protein-based coating.

The coating, prepared mixing egg white, yolk, cellulose from wood, and a turmeric extract called curcumin, keeps the perishable goods fresh for days. It is not expensive, neither does it change their appearance or flavour.

Muhammad Maksud Rahman, a Buet graduate and an assistant research professor at Rice University's Department of Materials Science & NanoEngineering, said he believes sustainable technology can solve some of the humanity's greatest problems. This is what inspired him to work on food safety and preservation, something that concerns him.

"We are living in a world where a huge quantity of food gets wasted even before they reach consumers due to issues centring supply-chain. At the same time, one in nine still goes to bed with an empty stomach every night and a third of the world's population suffer from malnutrition," he told The Daily Star in an interview lately.

His concerns also stemmed from the indiscriminate use of highly toxic preservatives like formalin in some countries, including Bangladesh. Wax coating is also commonly used, but studies found that it affects the human body.

Maksud, who was born in Chattogram and did his PhD at Cornell University in 2016 on "Protein-based Green Resins and Nanocomposites from Waste Residues", started looking for a safe and sustainable green strategy to preserve perishable goods without altering their biological and physicochemical characteristics.

Following extensive research, he settled on working to develop a protein-based biocompatible and sustainable alternative. He came up with the idea of using eggs because about three percent of all eggs produced in the US, or 200 million, end up in landfills, he said.

In 2018, Maksud and four of his students created the egg-based coating. In their initial experiment, they coated a few avocados fully with the mixture and kept some uncoated.

After a week, the eureka moment came when they found that the non-coated avocados turned black, whereas the coated ones were still green. "That was the very first positive sign of what was about to come, and we were really excited about the results," Maksud recalled.

He extended the experiment to other perishable food items such as bananas, papayas, and strawberries. He observed the same result: the uncoated ones ripened, while the coated fruits almost remained the same in terms of freshness.

Maksud explained that the egg-based coating significantly reduced oxygen exposure and water-loss -- the two factors responsible for ripening. The coating retained freshness, appearance, and aroma for at least one week longer than the uncoated samples.

Moreover, the coating completely dissolves upon washing for two minutes, thus dispelling worries for the vegans.

The work took one year and three months to complete, said the scientist.

In recognition of his work, Maksud was selected for the prestigious "Herschel M Rich Innovation Award" at Rice University in 2019. He was also selected as the "Sustainable Technologies Category Winner" in Create the Future Design Contest, a worldwide competition organised by Tech Briefs last year.

Maksud believes in collaboration to bring the best out of science. He took help from knowledge in the related field and noted academics like Prof Pulickel Ajayan at Rice University to develop the solution.

Currently, the team is set to test alternatives created with soy and corn proteins so that the coating can address the allergy issue related to eggs. Moreover, the researchers are extending their work to extract the protein from various fruits and vegetable wastes that are going to be used for producing the coating for vegans.

Additionally, the researchers will also work to test a spray protein to make it easier for both commercial providers as well as consumers looking for an at-home option.

For making the product commercially, the researchers are now carrying out technological-economic analysis.

"This will bring down the cost of the coating industry, cut food waste and help recycle food," said Maksud.

The scientist plans to roll out a startup early next year.

Asked about his thoughts on Bangladesh, Maksud said, "My beloved country has given me a lot; now it is my time to give something back."

He believes that the country has a huge pool of talented students and researchers, and he is interested in providing them with a strong research platform so that they can solve different problems with innovation.

He hired two Bangladeshi PhD students in his research lab last year who are doing exceptionally well, he said.

Also, he dreams of making his coating technology available in Bangladesh to save his own people from food hazards.