Keeping Fruit Fresh Longer with a Nanocellulose Film

David Palenski
9th January, 2024

Keeping Fruit Fresh Longer with a Nanocellulose Film

Image Source: Natural Science News, 2024

Have you ever wondered why the bunch of bananas you carefully selected at the supermarket seems to turn from perfect yellow to overripe brown nearly overnight? (Or is it just me?) The rapid ripening of bananas isn't just your imagination—it's a scientific fact. Bananas are what scientists call "climacteric fruit," which means they continue to ripen post-harvest. But what if we could keep those bananas ripe and delicious for just a bit longer? Enter the innovative minds at the Department of Biosystems and Biomaterials Science and Engineering, Seoul National University, where researchers have found an ingenious solution. They've created a special kind of film coating using materials that sound like they belong in a sci-fi novel: carboxymethylcellulose nanofibers (CM-CNFs) and red cabbage extracts (RCE). But what are these substances, and how in the world do they help extend the shelf-life of bananas? Let's start with CM-CNFs. Picture a thin, transparent film, almost invisible to the naked eye, derived from a magical process that starts with chemical modification (nothing too alarming, rest assured) followed by something that sounds suspiciously like making a smoothie out of chunks of wood – mechanical grinding. These nanofibers are long and skinny, giving them a high aspect ratio, which is just a fancy way of saying they're perfect for making really thin, spreadable films. The researchers didn't stop there; they created a suspension solution with these nanofibers. When this solution is coated onto bananas, something remarkable happens. As it dries, the CM-CNFs form a hydrogel network—a web of water-loving molecules that create a tight barrier over the skin of the fruit. Think of it as a microscopic moisture-wicking workout shirt for your bananas. It clings to their surface, controlling the fruit's breathing (yes, fruit breathe too, in their own planty way) and preventing the bananas from losing weight, which is a major part of the ripening process. Now, let's add a dash of color with red cabbage extracts (RCE). Red cabbage is more than a mere side dish; it's loaded with polyphenols. (These are the trusty antioxidants found in many a "superfood," known for their health benefits). Not only do these polyphenols give the cabbage its vibrant purple hue, but they also double as a knight in shining armor for our bananas. By locking onto the skin of the banana, the RCE works its antioxidant magic to prevent the appearance of those unsightly black dots, which are a telltale sign of age and decay on fruit. And get this: RCE doesn't just help with keeping the bananas looking pretty; it also works as a balm for the banana's overstressed skin, soothing and slowing down the ripening process. Basically, RCE calms the bananas down, telling them to take a breather and relax, thereby extending their youthful golden glow. But why, one might ask, is all this science necessary? (Why not just eat the bananas quickly or make a lot of banana bread, right?) Well, reducing food waste is actually a major concern globally. If bananas can stay fresher for longer, fewer will be thrown away. That means potentially less waste and more bananas making it from the farmer to your fruit bowl in prime condition. So, when will you see these invincible bananas at your local grocery store? The technology is there, but it might take a bit before it's commercially available (because, as expected, there's quite a leap from lab bench to produce aisle). But just imagine—a world where you can buy bananas without the pressure to consume them within a narrow window of perfect ripeness. Better for the environment, better for your wallet, and better for your peace of mind. It's truly fascinating, isn't it? Science continually finds ways to merge what we find in nature (like red cabbage and fibrous plants) with leading-edge technology to solve everyday problems. And all this to save the humble banana, a fruit that's so often taken for granted (that is, until it's gone brown in your fruit basket). The future of fruit preservation looks bright—and thankfully, it seems our bananas will too!



Main Study

1) Enhanced Preservation of Climacteric Fruit with a Cellulose Nanofiber-Based Film Coating.

Published 9th January, 2024

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