It's a bright red berry, shaped like a jellybean. When you first pop it in your mouth, you'll wonder what all the fuss is about. But eat it with something sour or bitter and you'll see how this little West African 'miracle' fruit has earned its name.
Each berry contains an unusual protein that tricks the taste buds lining the tongue. So foods that usually taste sour, bitter or savoury suddenly taste sweet and this taste-altering effect lasts for up to two hours.
The miracle berry, or Synsepalum dulcificum, grows in tropical areas of West Africa on bushes that can reach just over five metres tall. When ripe, the berries are around 3cm long.
The key ingredient is miraculin, the protein that produces the interesting taste-switching effect. Miraculin was first identified by scientists in 1968, although locals in West Africa have munched on these berries for centuries – usually before meals to make their food more palatable.
The first European records show miracle berries were documented in 1725 by Reynaud Des Marchais, a French explorer who tried the berries for himself when he became curious as to why African people ate the berries before eating dull and poor-tasting meals. He realised the berries took away the blandness and made meals much tastier than they really were.
More recently, scientists and nutritionists have started investigating the interesting health-giving potential of miracle berries. Some believe it could help tackle the Western world's obesity epidemic by being used as a low-calorie sugar substitute added to foods like cakes, biscuits and desserts.
How do miracle berries work?
The human tongue has about 10,000 taste buds that sit in the epithelium or surface layer of the tongue. Each bud is topped by a taste pore, like the skin pores on our face or body. Deeper in the tongue, each taste bud contains about 50 to 75 taste receptor cells.
When you eat, chemicals from food interact with the taste pore and the taste receptor cells. Those cells are connected to a system of nerve cells that communicate and pass information to the brain, so we then identify foods as sour or sweet, for example.
Miracle berries weave their magic in our mouth when miraculin sticks to taste receptor cells and changes how they work. They heighten the intensity of the tongue's sweet taste receptors and also change the shape of the receptor cells, overwhelming them with sweetness so that even acidic and sour foods register in our brain as sweet. So sucking on a lemon produces the same taste sensation as sucking on a lolly.
In the US, miracle berries have become part of 'flavour tripping' parties where guests eat the fruit and then sample a range of sour and acidic foods that all end up tasting sickly sweet.
But in the laboratory and kitchen, food experts and scientists are trying to work out how they can use miracle berries – in fresh or powdered form – to improve our health and our waistlines. For example, eating berries before eating a sugar-free dessert would give us the enjoyment of eating a sweet treat without the kilojoules.
However, at the moment researchers have not worked out how to stop miraculin losing its taste-switching properties when it is refrigerated or heated.
Another potential obstacle is that miracle berries are expensive. Miracle berry tablets are available online and cost around $30 for 10 tablets. A kilo of freeze-dried miracle berry powder from the US costs around $3100 – about half the cost of Beluga caviar. The high price is due to miracle berries being hard to grow, and researchers at the University of Tokyo are currently exploring how to cultivate the berries faster and more widely, to make them more affordable.
But the potential health benefits keep researchers committed to finding out more about how to make the most of miracle berries.
Another promising opportunity could be for cancer patients undergoing the rigours of chemotherapy. An unpleasant side effect of treatment can be a nasty metallic aftertaste and it may be that the miracle berry can combat this and return a sweeter, pleasant flavour to the mouth.
Researchers believe the fruit also has the potential to help people with diabetes to better control sugar intake by providing a sweet hit without the harmful sugar.
With more than 200,000 New Zealanders – and counting – diagnosed with diabetes, and complications of the illness including blindness and amputation, finding a berry that might reduce the number of those living with diabetes really would be a miracle.