WHYTASTE DON’TLIKE BANANA SWEETS BANANAS? H Alice Hirst delves into the differences between the bananas we eat today and their past counterparts.
ave you ever wondered why banana sweets never actually taste like a real banana? Well, that’s because artificial banana flavour is based on a type of banana that is no longer grown commercially.
If you were to have bought a banana before the mid-20th century, you would have most likely bought a Gros Michel. Also known as “Big Mike”, these bananas are fatter and more flavourful than the variety currently sold in shops, which is called the Cavendish. The Gros Michel contains a much higher concentration of a chemical compound, or ester, called isoamyl acetate. If you were to smell this ester on its own you would immediately recognise it as banana. Being cheap to produce and highly versatile makes this ester very popular as banana flavouring. In contrast, the Cavendish has more subtle and complex flavours that cannot be effectively replicated by isoamyl acetate. So, it is not so much that banana flavouring does not taste like bananas, it is more that bananas do not taste the way they used to. In addition to their richer flavour, Gros Michels also have a thicker peel which makes them much less likely to bruise and easier to transport. This then begs the question, why are they no longer available in the supermarket? The answer is simple: Fasarium oxysporum f.sp. cubense. This is a fungus which causes Panama disease, a condition that prevents banana plants from drawing water, causing them to wilt and die. In the 1950’s a mass outbreak of Panama disease almost wiped-out Gros Michel bananas, to the point that they could no
longer be commercially grown. Enter the Cavendish, which proved to be naturally more resistant to F. oxysporum, and thus succeeded in becoming the most common kind of commercially grown banana.
This might have been the end of the story about bananas, if it was not for one other feature. If you have ever eaten a banana you may have noticed that it did not contain any seeds. While wild bananas have large hard seeds, edible bananas are seedless. This means that store-bought bananas are sterile, and that they must be propagated asexually from offshoots. In other words, new banana plants are cloned from the fragments of a parent plant, meaning that all the bananas you find in the supermarket are genetically identical. So why does this matter? Although the Cavendish was originally cultivated due to its resilience towards Panama disease, in the late 90s a new strain arose called TR4. Unfortunately, the Cavendish is susceptible to this new strain, which has been working its way through banana plantations. Now, because all banana plants are essentially clones they lack the genetic diversity required to develop resistance to the disease, meaning TR4 could very well kill them all. Despite best efforts to prevent its spread, Panama disease has been working its way into all the major banana growing areas, including Asia, Africa, Australia, and South America. Unlike the last time, however, we do not have a new variety that could replace the Cavendish. Not only are bananas an $11 billion industry, they are also the planet’s favourite fruit.
While in the Western world they might be missed as a delicious and convenient snack, for millions in Latin America, the Caribbean, Africa, and Asia they are a fundamental source of nutrition. So, what can be done to save them? Some scientists are trying to grow new experimental and hybrid breeds in the hope of finding one that is both resistant to Panama disease and that also tastes similar enough to the Cavendish so consumers will not notice a difference. Others are trying to use genetic engineering to manipulate banana chromosomes with the aim of making the Cavendish tougher and more resistant to all disease. These solutions, however, are both difficult and time consuming. At the moment there is
If you have ever eaten a banana you may have noticed that it did not contain any seeds. While wild bananas have large hard seeds, edible bananas are seedless. yet to be a new banana with fruit that tastes good, ripens at a predictable time, can travel without being bruised, and that’s easy to grow in large quantities. The race is on to find one before it is too late.
Artwork: Jacob Gable, Bananas
I, Science
27
