The world’s most contentious culinary debates solved by science
CAN YOU SAFELY REHEAT RICE?
In a word, yes. Many people believe reheating rice causes food poisoning, but it’s the cooling of the rice rather than the heating that affects whether or not it’s safe to eat. Uncooked rice can contain spores of the bacterial species Bacillus cereus. They aren’t a concern during the initial cooking and eating process, but if left cooling at room temperature these spores can grow into bacteria. These bacteria multiply, producing toxins which can cause food poisoning. Don’t be fooled into thinking you can kill the spores off by reheating the rice, as the hardy bacteria can easily survive temperatures of up to 100 degrees Celsius. The best thing to do is to cool the rice quickly and store it in an airtight container. This prevents the spores from growing into bacteria, so as long as you thoroughly reheat your rice to kill off any other bacteria, it’s safe to eat.
WHY DO RED SWEETS TASTE THE BEST?
A surprising majority of sweets are red due to an inbuilt mental link with the ripeness of fruit. People are naturally drawn to red sweets because our brain links red with sweetness. Duane Mellor explains, “We do seem to ‘taste’ colour, so lemon- or orange-flavoured things that are coloured green will be said to taste like lime and more sour. Red things are associated with ripe berries, so we think of strawberries and cherries, so that is often more pleasant than green or yellow ones.” So when choosing a sweet, your sensory organs are naturally drawn to the red ones as your brain has identified them as the sweetest.
HOW COME I ALWAYS HAVE ROOM FOR DESSERT?
You’ve stuffed yourself at dinner but suddenly find extra room for pudding. Luckily, science can explain this phenomenon. “This has been described as taste specific satiety,” explains Duane Mellor. This is basically the idea of getting bored of one type of food and wanting another. Habituation theory also suggests that exposure to a variety of foods act as a stimuli; unlike the main meal, dessert is offers different flavours and textures, so although you’re full, you are not sated. Mellor continues,
“Some have also suggested that it is sowe get a range of foods and, in theory, a range of nutrients.”
WHY IS MELTED CHEESE SO DELICIOUS?
In 2011 Oxfam asked a cross-section of people from 17 countries what their favourite food was. Cheese made the list just once, coming in at 11th in the UK. However, pizza appeared on the list in 12 countries. Is it the dough? Is it the tomato? Or is it the melted cheese that makes pizza so universally popular? The cheese begins to melt at about 32 degrees Celsius as the milk proteins liquefy. Then at around 54 degrees Celsius the milk proteins break down entirely, leaving a thick
creamy, gooey substance. Creaminess is a soft texture our mouths love, while the warmth of the
melted cheese also appeals, making melted cheese infinitely better than its hard, cold original form.
WHY CAN STEAK BE EATEN RARE BUT NOT BURGERS OR CHICKEN?
Bacteria, such as salmonella and E coli, and other parasites live in the guts of animals and can be transferred to their flesh during the slaughter process. If ingested they can cause diarrhoea, vomiting and cramps. Cooking meat for 45minutes, with the internal temperature reaching at least 60 degrees Celsius, should be enough to kill off those bacteria, so thoroughly cooking chicken (and other poultry) all the way through should be safe. Steak, however, is cut from the muscle of the cow, not the flesh so as long as the outside is seared to kill off any surface-lurking bacteria, rare steak should be safe to eat. Burgers shouldn’t be eaten rare as contamination could occur while the meat is being minced, so treat your burgers the same way you would a piece of chicken and cook them thoroughly.
WHY DO KIDS HATE BROCCOLI?
Broccoli contains a glucos inolate compound that makes it taste bitter. The human gene TAS2R38 is responsible for sensing bitterness in food, and is more dominant in some people than others, so they’re more sensitive to the bitter compound andmore likely to dislike broccoli. Children have around twice asmany taste buds as adults, so if they’ve got a version of the dominant TAS2R38 gene then broccoli can taste horrible. However, as they get older the number of taste buds on their tongue can reduce, and theoretically this bitter taste will be less potent. DuaneMellor, senior lecturer in Human Nutrition at Coventry University, also points out, “This bitter taste is thought to be protective.
We are almost conditioned not to like bitter flavours as some bitter compounds can be toxic.”
SHOULD SANDWICHES BE CUT INTO RECTANGLES OR TRIANGLES?
This debate has dominated lunchtimes for generations but, while a recent YouGov poll found 60 per cent of Brits cut their sandwiches into rectangles, it can be put to bed thanks to that champion of the
triangle—Pythagoras. Cutting a 9x12-centimetre sandwich into two rectangles provides 21 centimetres of crust per half and nine centimetres of non-crust. Cutting it into triangles, however, still
provides 21 centimetres of crust per half but 15 centimetres of non-crust, an increase of over 65 per cent. Even if you aren’t fussed by the amount of crust, cutting your sandwich into a triangle exposes much more surface area of sandwich filling right from the start, engaging more of your senses, stimulating more of your taste buds, improving the first bite and making for a better sandwich experience.
