CrillGyter

27/01/2022

Why does Swiss cheese have holes?
There are thousands of kinds of cheese, each with its own color, shape, nutritional value, flavor and texture.

Since cheese is made from milk, cheese types tend to vary based on the source of milk. Some of the most popular cheeses are made from the milk of cows, goats and sheep. But there are also cheeses made from camel milk, water buffalo milk – even moose milk.

To make cheese, you need to add bacteria to the milk. These create chemical reactions that cause it to change into a combination of solid “curds” and liquid “whey.” The whey is generally drained off, concentrated and dried into a powder.

Variations in the amount and type of bacteria influence the taste and texture of the final product. Other aspects factor into the type of cheese that’s produced: the salting method, its temperature and how long cheesemakers age it, which refers to the amount of time it is left alone to ripen and form. Some cheeses are aged for as long as 18 years.

Like many other cheeses, Swiss cheese is made with cow’s milk and contains bacteria that help convert the milk into a solid.

So why does Swiss cheese have holes? Also called “eyes,” they’re so essential to Swiss cheese that when they’re missing, the cheesemakers say the batch is “blind.”

What makes Swiss cheese “holey” is additional bacteria called Propionibacterium freudenrichii subspecies shermanii – P. shermanii for short. Under the specific conditions that Swiss cheese is made, the P. shermanii produce a gas: carbon dioxide.

Because Swiss cheese is made at a warm temperature – around 70 degrees Fahrenheit – the cheese is soft and malleable. So as the bacteria grow, the gases they emit end up creating round openings. Think of blowing a bubble with chewing gum: As you blow air from your lungs, the pressure forces the gum into a circle. The bubble eventually pops, due to air pressure from your lungs or the atmosphere.

But when a bubble has formed inside a hunk of warm cheese – and then that cheese is cooled to around 40°F – the hole stays in place. The cheese now has its eyes.

It takes about four weeks at 70°F for the eyes to form. In total, it takes about six weeks to make Swiss cheese, and then it is aged two additional months before it is sold.

Swiss cheese was first made in Switzerland in the 15th century. But there, it’s known as “emmental” or “emmentaller.”

Other countries are also known for cheeses that are similar to Swiss cheese. France has Gruyere, while Italy has Fontina. In the U.S., cheesemakers concoct a modified version, called Baby Swiss, which tends to have smaller eyes. Gouda cheese – which originated in the Netherlands – is sometimes intentionally made with cultures that produce a little bit of gas and tiny eyes.

Fontina cheese also has ‘eyes.’ Brian Yarvin/Shutterstock.com
But in most cases, cheesemakers actually try to prevent the formation of gas in their cheeses. Especially in harder cheeses, gas doesn’t lead to nice, round eyes; instead, it forms unsightly crevices, cracks and splits.

27/01/2022

Hot curries, potato cheddar and muddy beetroot – some super surprising facts about your food
Spending a lot more time in your house doesn’t have to make you any less curious about the world around you. Just look inside your kitchen cupboards and there’s a wealth of chemistry just bursting to get out. Here are some surprising facts about the food you eat: why some things taste hot and cold without changing temperature, the chemistry behind cheese connoisseurship, and why a squeeze of lemon could make beetroot – and some fish – more palatable.

Why mints are cold but curries are hot

Hoooootttt and cold!! Johan Swanepoel & Banu sevim/Shutterstock
Our nervous system is packed with receptors, which are proteins embedded in cell membranes. Ions generally cannot move freely across these cell membranes, but must enter or exit a cell through ion channels (which you can think of as tiny gates) which convert chemical messages into electrical signals, which your brain interprets as a sensation. Under certain conditions, ion channels open and allow the ions to move in or out of the cell, creating an electrical signal. For the most part, the receptors detect the correct stimulus, be it chemical, light, or vibration. But sometimes these ion channels can be fooled.

Transient receptor potential channels (or TRPCs) are a type of ion channel which behave like mini thermometers. An example of which, called TRPM8, responds to lower temperatures (below 26°C) and to the menthol molecule found in minty flavours. So when you eat something minty, this ion channel opens and your senses are fooled. The cooling sensation it produces means menthol is found in many applications such as lip balms, decongestants, cough mixtures, mouthwashes, toothpastes and treatments for aches and pains. Some athletes say their performance improves when inhaling minty flavours, and that’s why they chew gum.

Another example of this type of ion channel is TRPV1. These channels respond to heat (above 43°C) and capsaicin (a molecule found in chilli peppers) also activates them. The burning sensation in your mouth when chewing chillies is due to capsaicin. Your brain is convinced you’re eating something hot, despite no actual change in physical temperature. These receptors are clustered on our tongue, in our mouth and on our skin because their aim is to prevent us from sensations that will burn us but capsaicin also triggers it too, giving a false response.

Have you ever put your hand in really hot water and it has initially felt cold? Some cold receptors can be activated by both low temperatures and extremely high temperatures and is a phenomenon known as paradoxical cold sensation. It’s usually corrected within a matter of seconds.

Have you ever jumped into really cold water and noticed the initial shock wears off pretty quickly? The proteins in the ion cells become desensitised, so it’s not quite as bracing as your body gets used to it. This is highlighted by frequent cold-water swimmers, who generally don’t have the extreme response to cold as novices do.

Take three bowls. Andre Helbig/Shutterstock
You can demonstrate really easily how our heat sensors can be fooled. Get three containers, large enough so you can submerge your hand. Fill one with cold water, one with hot water (usual bath temperature is fine) and one with warm water. Place the container filled with warm water in the middle of the three. Place one hand in the cold water and one in the hot water for one minute. Then simultaneously put your hands into the middle container containing the warm water. You’ll be amazed at the perceived difference in temperature and the ease at which we can fool certain ion channels.

Cheddar that tastes of boiled potato

Some cheese … TunedIn by Westend61/Shutterstock
Milk is primarily water, and suspended in the water are solids – mainly proteins called casein and whey. To make cheese, you have to separate these two proteins. If the milk is not heated (unpasteurised), bacteria naturally present will start to turn it sour.

But the milk used to make cheese these days is pasteurised and heated to remove unwanted bacteria, so the bacteria which gives cheese distinctive flavours (such as Streptococci and Lactobacilli) are added afterwards, along with an enzyme called rennet, and the mixture is processed at 30-40˚C for a couple of hours. During this time, lactose – the natural sugar in the milk – is fermented into lactic acid, reducing the pH at which point the rennet helps to coagulate the casein protein, forming curds.

Curds have the consistency of a rubbery gel. They are set for an hour or two before the liquid whey is separated by cutting the curds into small pieces and draining it away. What you’re left with is cottage cheese. These drained cheese curds have a soft consistency, with some of the whey still present. Ever wondered why cottage cheese doesn’t have a strong taste but does taste slightly sharp? It’s due to the pH decrease and the fact the volatile flavours haven’t had the time to develop.

Some cheeses have additional bacteria injected into them or brushed onto their surface to mature into distinctive tastes. Others are warmed to release more whey, making them firmer and less rubbery. Softer cheeses ripen faster by the action of bacteria as they contain more water. That’s why hard cheeses such as parmesan can last for weeks in your fridge – it contains less water, which bacteria find difficult to survive in.

The longer you leave a cheese before eating it, the more lactose is converted into lactic acid so older cheeses tend to have a sharper taste. In cheddar, the curds are mixed with salt before the whey is drained and this makes it a difficult breeding ground for bacteria. Extra mature cheddar is much stronger in flavour than mild cheddar and needs to be matured for over a year. During this time, the proteins are chopped up into amino acids, which break down further to produce all the different flavour chemicals.

Cheddar contains hundreds of compounds at detectable thresholds. Try some cheddar and see if you can detect furaneol and homofuraneol (caramel), δ-dodecalactone (peach/coconut), butanedione (buttery), ethanoic acid (sharp, vinegar), (Z)-4-heptenal (creamy, biscuit) and methional (boiled potato).

Gorgonzola and other blue cheeses get their distinctive taste from a class of chemicals called methyl ketones. In gorgonzola, 2-heptanone and 2-nonanone impart “blue cheese” notes. But try some gorgonzola to see if you can also taste 1-octen-3-ol (mushroom), 2-heptanol (fresh, lemongrass), ethyl hexanoate (apple), ethyl butanoate (pineapple), 2-nonanol (waxy) and 4-methylanisole (mothballs!).

When you tune your taste buds into the different flavours, why not try these:

• Can you taste methanethiol in camembert? It smells of cabbages.
• Can you taste 3-methylindole in Swiss cheese? In low concentrations it’s rather sweet; you’ll find it in orange blossom and jasmine, but in higher concentrations it stinks of manure.
• Can you taste ethyl octanoate in pecorino? It’s a taste associated with oranges and apricots.
• Can you taste phenylethanoic acid in gruyère? It gives a sweet, honey, malty, vanilla-like taste.

It’s amazing to think that all the flavour molecules found in cheese derive from just three starting materials – lipids in the milk fat, lactose (a sugar) and casein (a protein).

Why beetroots taste really ‘earthy’

Beetroot soup – or is that mud soup ..? Foxys Forest Manufacture/Shutterstock
Some people just don’t like the taste of beetroot. If you ask someone what it tastes of, chances are they’ll use the words “earthy” or “muddy” and is quite unlike the taste of any other food. The chemical geosmin is responsible for this.

Geosmin is a terpene, produced by a class of plant-eating microorganisms called Streptomyces coelicolor and are released when they die. Terpenes are a strong-smelling class of compounds and help to protect plants from parasites and predators.

The amount of geosmin in beetroot is genetically determined and food scientists rate varieties based on geosmin concentration. Some varieties contain two or three times more geosmin than others, so if the earthy flavour is what’s stopping you from enjoying it, choose your variety carefully.

While some people like the earthy taste of beetroot, geosmin isn’t a molecule welcome elsewhere. People who take their drinking water from surface sources may experience a muddy taste. There have been cases where utility consumers complain about the taste of their water and it has been traced back to geosmin. Also, blue-green algae release geosmin when they die and this can be absorbed by certain freshwater fish such as trout or eel, which can give them an unpleasant taste. Geosmin is rendered odourless by an acid, so these fish are often eaten with a squeeze of lemon juice. And people who don’t like the taste of beetroot may find it more palatable when eaten with lemon.

If you’re struggling to know what foods pair well with beetroot, why not try them with other earthy flavours generated by aromatic pyrazines? Foods such as roasted onions, coffee or even dark chocolate might sound like an odd combination, but complement beetroot really well.

27/01/2022

The psychology of comfort food - why we look to carbs for solace
Amid the global spread of COVID-19 we are witnessing an increased focus on gathering food and supplies.

We’ve seen images of supermarket shelves emptied of basics such as toilet paper, pasta, and tinned foods. Messages to reassure people there would be continued supply of provisions has done little to ease public anxiety.

Panic buying and stockpiling are likely responses to heightened anxiety, fear and uncertainty about the future. COVID-19 poses an imminent threat.

Being able to exert some control over the situation by gathering goods to store for lockdown is one way individuals seek to manage anxiety and fear, and feel protected. But why do we seek out certain foods, and should we give in to cravings?

Gathering food supplies might bring feelings of security - but having large amounts on hand is a double-edged sword. Louis Hansel/Unsplash, CC BY
Retreating into our pantries
On the one hand, newly stocked and plentiful pantries, fridges and freezers reassure us that food is readily available and puts supplies within easy reach. At the same time, feelings such as loneliness, anxiety, depression, and stress may increase as we retreat and become housebound. So, we may be more vulnerable to what is referred to as “emotional eating” during this challenging time.

Reaching out for food to comfort oneself is an attempt to manage or alleviate negative emotions. A person’s tendency to emotionally eat can be measured using questionnaires such as the Emotional Eating Scale, which asks about eating in response to anxiety, depression and anger.

From an early age, infants learn to associate feeding with being soothed and social interaction. In everyday life, food is often used to enhance mood or “treat” ourselves. Eating tasty food releases dopamine in our brains, which is strongly associated with desire and wanting for food.

Eating sweet and fatty foods may improve mood temporarily by making us feel happier and more energetic while also satisfying our hunger. However, if comfort eating becomes a habit, it often comes with health costs, such as weight gain.

Research by Mantau and colleagues in 2018 found emotional eating is most likely to occur in response to stress and in individuals who are trying restrict their food intake (“restrained eaters”). These factors were more important in explaining people’s food choices than biological factors such as hunger.

Other studies have also shown that trying to suppress food urges can be futile and have the opposite effect to the desired outcome. For example, dieters have been found to experience strong cravings for the very foods they were trying to restrict.

Doing it tough
Employment insecurity, financial difficulty and hardship due to the COVID-19 pandemic are affecting the lives of many people. Past research has shown that poverty is associated with psychological distress, including higher rates of depression and lower mental well-being. Again, people’s ways of coping with this distress could have further ramifications for their health.

Setting up healthy habits for this ‘new normal’ time might help maintain balance. Yonko Kilasi/Unsplash, CC BY
Research shows those in lower socioeconomic circumstances were more distressed, and more likely to turn to emotional eating as a way of coping. This emotional eating was, in turn, associated with increased body weight.

This suggests it is not distress or biological make-up but people’s ways of coping (using food) that may be critical in explaining why some people gain weight in response to stressful life events. People with a history of socioeconomic disadvantage may also find it harder to cope with emotional distress, perhaps due to factors such as lower social support. As a result, they may be more vulnerable to using food as a way of coping.

Toasty crusty goodness
Baking has become a strong theme on social media. The hashtag has taken off and has over 65,000 posts.

Research suggests there are likely benefits from engaging in cooking. The psychosocial benefits of baking have been shown to include boosts in socialisation, self-esteem, quality of life, and mood. Cooking with children may also promote healthy diets.

By providing and sharing food with other people, baking may strengthen social relationships and make us feel closer to our loved ones. This may explain why it has become so popular in these times.

Coping with lockdown
During this time of social isolation, it’s tempting to reach for food, but a healthy balance remains important.

Creating a “new routine” or “new normal” which includes a variety of activities – exercise, baking, music, reading, online activities, working or studying, relaxing, keeping in touch with friends and family - may help maintain a sense of well-being, and assist in managing meal times and food intake.

Mindfulness meditation practice may be useful in managing emotional eating and weight. Research has shown that Mindfulness Based Interventions (MBIs) are effective in managing emotional eating, reducing weight and improving obesity-related eating behaviours.

Weight management initiatives should encompass psychological factors such as mood and distress. Teaching people to develop positive coping strategies in these challenging times (problem solving, positive help seeking, relaxation techniques) may be particularly effective.

27/01/2022

27/01/2022