FRIENDLY MICROBIES: BREAD

What were the first loaves of bread like?

Grains of wheat were ground using only stones and the sieve would not be invented for a very long time to come. The dough was not left to rise either – this was unheard of at the time. The result of all this was a type of very hard flat biscuit that was definitely difficult to chew. Of course, primitive man did have an enormous mouth. It was only after fire was discovered and tools invented that the muscles of the mouth did not have to work so hard. In fact, the human mouth went through a major transformation over thousands and thousands of years and, today, is much much smaller than the mouths of our first ancestors (which is why our wisdom teeth usually give us so much trouble).

It is believed that it was the Egyptians (around 2600 years before Christ) who began to make bread using a more similar process to the current one: leavened with added salt and baked in an oven. But why did people start to leaven bread? As far as we know, like most other discoveries, it was an accident. Somebody had accidentally left dough in the open air from one day to the next. And surprise, surprise! The following day, the dough had risen to twice its size. Now this is where audacity came in: the same someone actually dared to put it in the oven. “No pain, no gain” as the saying goes - in this case, the bread turned out to be much softer, tastier and crustier – a real treat! And of course, this person continued to make bread the same way for the rest of her life - her, her relatives, friends, neighbours and so on. Of course they never understood the reason for this phenomenon; this was only unravelled about a century ago when French scientist Louis Pasteur discovered that a microbe was responsible for the entire process. A microbe? I hear you ask. Yes, a microbe! Microbes are really tiny beings: so tiny that we can only see them with the aid of a microscope. Hence the name: micro = very small and bio = life. You might not know this but with microbes, just like with people, there are the bad guys, which cause discomfort, spread disease and destroy our food, the truly useful guys, and the absolutely fantastic guys, without which life would not even be possible. This may seem like an exaggeration, but it is not.  The microbe which causes the dough to rise is one of the very useful microbes. It is a yeast, hence the name yeast bread. The yeast reacts with some of the components of the flour (sugars) and slowly releases a gas – carbon dioxide – and an alcohol – ethanol – as well as other substances which give the bread its taste and a smell that makes your mouth water.

It is the gas that is produced (carbon dioxide) that causes the dough to rise. If the dough is made with wheat flour, it is capable of “holding” this gas and slowly increases

in size. Cornbread, on the other hand, which is made only with corn flour, remains flat, dense and dry - very different from wheat bread.

MICRÓBIOS AMIGOS (cont.)

Try this experiment:Get a little yeast from the bakery or some dried packet yeast, which is usually sold in the desserts section of most supermarkets. Mix one cup of flour with lukewarm water and add one level coffee spoon of yeast (it may not seem much but I can assure you there are millions of cells in it). Cover the bowl with a cloth and let the mixture rest for about an hour. Take a look at what is happening every 20 minutes or so. “Watch and see” as they say. Even better, watch and measure the height of the dough with a ruler and keep a record of the different measurements. Maybe you have made bread before, but this time you will be amazed at the hard work done by an organism as microscopic as bakers’ yeast. Have you ever noticed the ingredients of bread sold in the supermarkets? Sometimes it says that it is made of wheat flour type 45, or 65, 80, 110, etc. What does this mean? Well, for now, it means that the higher the figure, the less white the soft part of the bread will be.  After the grains of wheat have been ground, they are passed through a sieve. This can be done using only the inner part of the wheat grain to make the flour – and we get a really white flour – or we can make a fairly brown flour, which includes the outer layers of the grain.  The numbers on the packet are related to the amount of bran in the flour. For example, type 150 flour has a much higher bran content than a type 45 flour.  There are those of us who think that bread is fattening. One thing’s for sure: it is one of the most important ingredients in our food supply and is even better if it is a little browner, that is, if it has more bran (more fibre). What is devastatingly fattening is the butter we so generously spread on our bread… and the ham, the cheese and the other things we put on our sandwiches. It is the fillings that make us fat. Just as a matter of interest, did you know that the word sandwich originated from the name of an English earl – the Earl of Sandwich (1718-1792), whose name was John Montague, and who began to eat meat and other things between two slices of bread in order to be able to play cards without stopping to eat (he was so addicted). It had the advantages of not having to dirty his hands or get up.  But sandwiches have other benefits too. It is a quick food which means we don’t have to spend a lot of time eating. But this isn’t usually because we want to have more time to play cards. If only!E, por último, sabia que a palavra companheiro (do latim ‘cum’ + ‘panis’) vem dos tempos em que cada pessoa, à mesa, partilhava o seu naco de pão com o vizinho do lado? Ou seja, um bom amigo era aquele com quem partilhávamos o pão. Outros tempos!

Maria Margarida Guerreiro

Cross section of a grain of wheat BranEndospermGerm