Which preparation techniques change the properties of food?

Biochemical, mechanical and thermal techniques modify the texture and flavour of food or even make it easier to digest.

How do we make bread?

Kneading is a mechanical technique to mix wheat flour, water and yeast. The dough is then left to prove. This is a special term for fermenting bread, when the yeast consumes the starch in the flour, producing bubbles that make the bread rise. This is a biochemical technique. Then a thermal technique is used. Cooking triggers the Maillard reaction, which gives bread its colour and flavour.

How do we make beer?

Malting is a biochemical technique during which barley germinates, transforming the starch into sugar. We can see germination happening when little shoots grow on the grains.
During fermentation, the malt is mixed with water and hops and then yeast, which converts the sugar into alcohol and carbon dioxide. This makes the beer fizzy.

How do we make cheese?

Making cheese requires the use of various techniques. Curdling milk is a biochemical technique. The cheesemaker heats the milk and then adds lactic acid bacteria and rennet, an enzyme that breaks down milk proteins.

Then come a series of mechanical techniques:

• Slicing: The curd is cut with a wire frame.
• Churning: The cheesemaker stirs the curd.
• Collecting the curd: The curd is drained through a large cloth.
• Pressing: The curd is put into a mould and pressed.

This is followed by a biochemical technique: fermentation. The cheesemaker turns the cheese over regularly for around twenty hours, then removes it from the mould, salts it and stores it in a cool cellar. Fermentation continues as the cheese matures.