Transition-year student at Dungarvan CBS in Waterford, James Hickey is on a mission to develop a pH-sensitive, biodegradable food packaging film using red cabbage extract to indicate spoilage and enhance food safety.
James’ project titled ‘Spoiler Alert: pH Responsive Packaging for Food Preservation’ has been qualified for the BT Young Scientist and Technology Exhibition (BTYSTE), which will take place from January 9-11, 2025, at the RDS in Dublin.
Inspired by his favourite subject chemistry and his parents’ work in pharmaceuticals and their farming backgrounds, the transition-year student said he was looking at experiments with pH indicators for his BTYSTE project.
Speaking to Agriland, James said he is currently on his fourth or fifth batch trialling a pH-sensitive, biodegradable film using natural components such as red cabbage extract and chitosan, which is a sugar from shellfish.
“With my film, on each package, there would only be a small [pH indicator] strip and it changes colour as the food spoils. So as the acid would increase, the pH strip would change colour.
“I knew that red cabbage contains anthocyanins and that’s where the colour change comes from. Then I had to research biodegradable polymers and turn it into a plastic like filler material, so that’s what the chitosan does,” he said.
James hopes his film could replace expiry dates, which he believes may not be the most accurate way to determine food safety, saying “there should be a more accurate way so you don’t have to rely fully on the expiry date”.
BTYSTE project
The student has been working in the school laboratory most school weeks to improve the film under the supervision of his science teacher, Maria McSweeney, to whom he is thankful for being “super helpful and supportive” with his project.
Speaking about the process of his trials, James said he blends, filters and strains the red cabbage until he has a liquid extract the night before, and then dissolves the chitosan in a acetic acid and water solution in the school lab the next day.
James also adds glycerol to make the film more flexible, and uses acetone for dehydration before pouring the solution into petri dishes which then go into the oven at 40°.
Despite researching other anthocyanins such as blueberries or turmeric, James said he went with red cabbage as a pH indicator as it usually has the broadest colour range, changing from a pink or red colour at pH1 to yellow at pH14.
Reflecting on his trials to date, he said the first batch didn’t set so he used more chitosan and glycerol to make it more solid and thick, which worked well. At other stages the film was breaking too easily and was hard to get off the petri dishes.
Some of James’ developed packaging films, which he intends to use mainly for meat and dairy products, but potentially fruit too, are currently in the drying process, following which he will test how long they take to decompose.
From researching online, the transition-year student told Agriland he expects the packaging films to decompose within a timeframe of roughly one to two months.
With six weeks to go, James said he can’t wait for the exhibition, hoping to succeed in the food safety or agriculture categories. He had previously entered the competition with a project on how colour affects our perception of taste.
“Sometimes we associate specific colours with foods, and if we change the colour of them, then our brain assumes they’re going to taste differently.
“We assume salmon has a bright pink-orange colour, but they also breed salmon that can be a pale colour. When tested blindfolded, there is no difference, but when they could see the colour, they assumed that it didn’t taste as nice,” he said.