What would happen to chocolate if you didn’t eat it for a hundred years?

What would happen to chocolate if someone could not eat it for 100 years?

Kaaro Kotiranta, 7

Although chocolate is a pretty irresistible treat, some people have managed to keep it for over a hundred years. For example, the queen Viktoria in 1900 sent chocolate gifts to the soldiers of the British army fighting in the Boer War, some of which have survived.

Based on reports and photos, they are no longer in edible condition, but hard, dry and crumbly, and some are discolored. Their smell is pungent and cardboardy, although the faint chocolate aroma can still be recognized by sniffing.

However, chocolate is one of our best-preserved foods. Good shelf life is based on its composition. For example, a typical dark chocolate contains about 45 percent fat, i.e. almost half, about 35 percent sugar, about 7 percent protein, and about 12 percent starch and fiber.

Water, which microbes, i.e. tiny organisms, need to grow, chocolate contains at most one percent. Therefore, chocolate is not a delicacy for bacteria and molds, and thus it does not spoil.

However, the raw materials of chocolate begin to change little by little over the years and decades. The cocoa butter in chocolate, which is often crystallized into a wonderfully melt-in-the-mouth form, is starting to find its way into more sustainable forms. That change starts to be seen in fairly fresh chocolates, for example only a couple of years old, as a grayish layer on the surface.

Over the decades, the fat in the chocolate also starts to go rancid, which gives the chocolate, for example, cardboard-like and musty aftertastes. The sugar, which in fresh chocolate is in the form of microscopically small sugar crystals, begins to turn into larger crystals over the course of decades. In this case, the texture of the chocolate becomes sandy and dry.

If you want to monitor the changes in chocolate yourself, you could store, for example, ten identical chocolate bars in the cupboard and open and taste one of them once a year. That way, you could collect an interesting ten-year time series of sensory changes in chocolate, if you can’t bear not to eat the delicacies waiting in the cupboard.

They are Hopi

professor of food development

University of Turku

Why doesn’t an adult grow anymore?

Okko Tiusanen, 3

Human height growth is the result of lengthening of bones. Bones grow in length in special areas called growth plates. They are located near the ends of bones, for example inside the long bones of the arms and legs. During childhood and adolescence, the bones in these areas constantly grow slightly longer.

During puberty, which is usually between the ages of 11 and 17, many changes occur in the growth plates, just like in the body in general. The growth plates then gradually lose their ability to function. Because of that, adults can no longer grow taller.

Height growth usually stops around the age of 18, slightly earlier in girls than in boys.

The final size of the bones is largely determined by hereditary factors. Today’s young people are on average taller than their great-grandparents, which the reason is estimated to be especially better nutrition and health care.

The cessation of height growth due to the disappearance of the growth plates is especially characteristic of humans and other mammals. Some animals, such as mice and other rodents, grow somewhat even as adults. Over time, natural selection has determined what size and how long any animal species grows.

Although people’s height growth stops as adults, many cells located elsewhere, i.e. the building blocks of the body, can grow. For example, if we eat more than necessary, fat cells can grow larger, so the waist circumference and other parts of the body can grow even in adults.

Kaisa Ivaska-Papaioannou

docent of cell biology and university lecturer

University of Turku

Why do loud sounds resonate in the cold, but not in the heat of summer?

Autumn Säilynoja, 7

My voice echoing can mean that the sound sounds louder or that the sound is heard several times. The main reason for reverberation in freezing temperatures is certainly that the icy ground is a hard surface that reflects sounds well. In this case, the sound may sound louder and echoes may be heard. In the summer, the vegetation and soft ground, on the other hand, dampen sounds.

On longer journeys, sounds, or sound waves, always turn in the direction of colder air, so in summer they escape into the sky and are attenuated faster. In winter, it is so cold on the surface of the earth that sounds do not escape to the sky. In addition, cold, denser air carries sound better than warm, less dense air.

You can get a special reverberating experience of frost by standing on the shore of an icy and snow-free body of water. When the ice breaks, the sound bounces around inside the ice, which can be heard as an echo in both senses of the word, just like in a hard-walled room.

Tapio Lokki

professor of acoustics

Aalto University

Why don’t people and some animals get permanent teeth right away?

Emil Ahava, 5

Of people in addition, most other mammals also develop two dentitions, i.e. milk teeth and permanent teeth. In mammals, both dentitions begin to develop already during fetal development, but the permanent teeth first wait their turn inside the jawbone.

Baby teeth are fewer than permanent teeth and they are smaller in size because they are enough for a little one to begin with. The food of a small mammal child is milk at first, so stronger teeth and all teeth are not yet needed to chew food.

Baby teeth can be called practice teeth. With their help, the jaws gradually become stronger so that you can start eating more solid food.

The mouth would also be very cramped if the permanent teeth immediately filled the tiny mouth. The teeth would then not have enough room to grow. Chewing food would also not be effective in this case.

Countless other animal species have permanent teeth instead of baby teeth.

For example, crocodiles and sharks and other cartilaginous fish have teeth ready for use immediately after birth, after which they grow continuously and are replaced by new permanent teeth throughout life. It is to their advantage, because they immediately use meat and not milk as their food.

In turn, the permanent teeth that elephants change between help them efficiently utilize all possible plant food to nourish their huge bodies.

Kirsi Sainio

docent of developmental biology

University of Helsinki

Send the question, the questioner’s full name and age to lasten.tiedeskö[email protected]. The column is provided by Touko Kauppinen.