Festive science facts

Roasts:

One of the better aspects of Christmas is the food. A juicy roast is a must, and the process of roasting sets off many chemical reactions that few other methods can match.

Whatever meat you choose, it is the muscle tissue that you will be dying to tuck into. Muscle tissue normally consists of around 75% water, 20% protein, and 5% fat and carbohydrates. In raw meat, the proteins are coiled and relatively strongly bonded together. The oven acts as a thermodynamic reactor and once up to the necessary temperature, specific to the proteins in the meat, the bonds break and the proteins unravel and denature. This process makes the Christmas roast nice and tender.

But why does roasted meat taste so good? The answer is in one of the chemical reactions that takes place: the Maillard reaction. Discovered in 1912 by French chemist Louis Camille Maillard, this reaction takes place when carbohydrates, specifically sugar molecules, are heated, at roasting temperatures, with amino acids.

Many different compounds are formed as the carbonyl group of the sugar reacts with the amino group of the amino acid to form N-glycosylamine. These undergo Amadori rearrangement, an important organic isomerisation reaction that creates compounds with the same molecular formula but different structures, producing ketosamines. It is this group of molecules that not only produces the rich and delicious flavours we associate with roasted meat, but also the melanoidins which give the roast that golden brown colouring.

Effects on Genes:

The overindulgence at Christmas may damage your health in a rather surprising way. Your genes may be adversely affected by some of the foods traditionally eaten during the festive season.

Dr David Topping of CSIRO, Australia’s national science agency, warns that over consumption of certain nutrients can affect your DNA. “There is a school of thought which says that over nutrition leads to the production of molecular oxygen species that can lead to damage of the DNA,” he says.

Not only are there general dangers with any over consumption, but the traditional bird of choice, the turkey, seems to make matters worse. This inconspicuous meat is high in dietary protein. “We’ve shown that increasing the amount of protein will increase genetic damage to cells that line the large bowel,” explains Topping.

However, those of us who only like Christmas for the opportunity to gorge ourselves will be glad to hear that you can avoid this form of DNA damage by eating a specific dietary polysaccharide: the humble potato. Dr Topping says that starch that is not digested in the small intestine can produce protective compounds in the gut that prevent the damage.

Hangovers:

The most important thing about Christmas is the brilliant excuse to drink excessively. Sherry and mulled wine are the standard beverages but any alcoholic drink can lead to unwelcome side effects.

The hangover, technically known as veisalgia from the Hungarian word for “after night of too much fun you do not want to, and will not be able to remember” (kveis) and the Greek for “pain” (algia), is caused by the alcohol in the blood blocking the secretion of the hormone vasopressin from the pituitary gland.

When the hormone concentration in the blood drops, the kidneys send water directly to the bladder, acting as a diuretic and preventing the absorption of water. This diuretic effect leads to dehydration, which causes problems for the brain.

As blood flows through the brain, due to the low concentration of water in the blood, water is drawn out of the brain cells and shrinks the brain, causing it to pull away from the skull which ultimately causes the headache.

Christmas Trees:

The traditional real pine tree is slowly being replaced in homes up and down the country by fake, plastic Christmas trees. However, there is one good reason to appreciate the real thing.

Researchers have isolated a group of anti-inflammatory compounds in the bark of the Scotch pine, widely used as Christmas trees. The scientists say that these compounds could be developed into drugs to treat pain and arthritis.

The leader of the research group, chemistry professor Kalevi Pihlaja from the University of Turku in Finland, explains: “The preliminary study showed that highly purified preparations of pine bark extract have potent anti-inflammatory effects. In the future, this may mean that people with arthritis may ease their pain by eating food supplements made from Christmas trees.

The researchers found that the compound extracted from the pines inhibits nitric oxide production, an excess of which has been linked to arthritis and circulatory problems, and also inhibits prostaglandin production, linked to arthritis and pain.

If you are suffering from pain or arthritis, it is probably still not a good idea to chomp your way through your tree.

Reindeers and Santa Claus:

Roger Highfield, author of Can Reindeer Fly?, suggests that, in order for Santa to deliver the huge number of gifts in time, across the globe, he would have to achieve such high speeds that the forces on his body would be 17,500 times greater than gravity on the surface of the Earth and would crush him into a singularity.

However, Roger rightly points out that: “Santa is not dead. He delivers presents every year, as reliably as Rudolf’s nose is red.”

But why is Rudolf’s nose red? Despite being able to withstand crushing forces, Santa has been unable to cure the common cold.

Reindeer noses contain elaborate and highly concentrated folded membranes which act as heat exchangers. Cold air, when inhaled, is rapidly warmed by the blood in the membranes as it enters the body. The exhaled, warm air is cooled before leaving by the same process. This helps reindeers retain heat and minimise moisture loss.

However, this moist respiratory system makes a wonderful home for parasites and bacteria, including 20 known so far that are unique to reindeer. Odd Halversen of the University of Oslo has suggested in the journal Parasitology Today that the “celebrated discolouration” of Rudolph’s nose is probably due to a parasitic or bacterial infection of his respiratory system.