We all know the struggles of eating an ice cream on a hot summer day – trying to enjoy our treat while simultaneously preventing the sticky sweet stuff from dripping all over our hands. Thankfully, researchers have just found an all-natural way to let you enjoy that summertime snack without the hurry.
A new study from the Universidad Pontificia Bolivariana in Colombia and the University of Guelph shows that extracts from banana plant stems can be added to ice cream to slow down the melting process. The work was presented at last week’s 255th National Meeting & Exposition of the American Chemical Society (ACS).
Banana farming is one of the main agricultural industries in Colombia, and with it comes a considerable amount of waste. After chopping off and harvesting the large bunches of fruit, the banana plant stem, or rachis, is usually left in the field.
But for Robin Zuluaga Gallego, Professor of agro-industry at the Universidad Pontificia Bolivariana, these leftovers are pay dirt.
Gallego uses alkaline solutions to extract cellulose micro and nanofibers from banana rachises. Plant fibers like these are being added to polymeric materials like car doors, not only to make materials “greener” and more sustainable, but also to make them lighter and stronger.
These same principles can be applied to food engineering, where a lot of time and effort is spent giving your favourite snacks the perfect texture, crunch, or chewiness.
“We wanted to take advantage of our experience in the manufacture and incorporation of CNFs, and evaluate their effect in a complex and fascinating food matrix such as ice cream,” says Gallego.
For this study, Gallego teamed up with Professor Douglas Goff from the University of Guelph. Originally intending to follow in his father’s footsteps and work at Brookfield ice cream in Nova Scotia, Goff got hooked on the research side of things, and has been studying ice cream at Guelph for over 30 years.
Taking advantage of Goff’s expertise and Guelph’s pilot scale ice cream manufacturing facilities, Gallego’s PhD student Jorge Velásquez Cock, tried incorporating the banana stem-derived cellulose nanofibers into high- and low-fat ice cream at varying concentrations.
“Microcrystalline cellulose has been used as a food ingredient for over 50 years,” says Goff, “but instead of cutting the cellulose into small spherical particles, Gallego’s process cuts it into long, thin fibres, kind of like spaghetti. As a result, it has the unique ability to set up a structure.”
It’s this structure that holds together the ice cream ingredients and stops the oozing process, even though the overall ice melting temperature has not changed. With just 0.3 g of the nanofibers in 100 g of ice cream, there was a 20-minute delay in the onset of melting.
This is useful for increasing your enjoyment of the product on a hot summer day, but is also great for ice cream producers, because they don’t have to worry about melting and re-freezing from temperature fluctuations during transport and storage.
The banana fibres also give the ice cream a more pleasing, creamier texture – something that could improve the properties of low-fat ice cream, which tends to be icier and less satisfying.
“The next step is for an ingredient company to pick up on this and investigate the potential for extraction of these fibres from banana stems,” says Goff. “It has to be a commercially available ingredient.”
On the research side, Gallego is interested in exploring the interaction of the banana cellulose nanofibres with other fats such as vegetable oils, to potentially corner the frozen dessert market as well.
It just goes to show that one person’s banana can be someone else’s ice cream.
