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A pizza is a round and flat yeast bread that is bountifully filled with tomato sauce, cheese and other ingredients. The first pizza, as we now know it, was baked in Italy around 1700. In 1975 the frozen pizza was introduced.
|Production process of a pizza bottom|
|Production process of a pizza|
In the production process mentioned below the process of a frozen pizza is described. Frozen pizzas are pizzas that are prebaked and frozen. In order to consume them they only need to be baked off. Frozen pizzas are produced on large scale.
olive oil, emulsifier, sugar and bread improvers are mixed. The bread improvers make sure that the bread has a longer storage life. In 10 minutes all ingredients are thoroughly mixed. It is important that the salt is added later than the yeast. If the salt directly contacts the yeast the yeast cells die and the yeast looses its function.
flour form the structure of the dough. When an elastic dough is obtained the dough is ready for the next step.
aromas and carbon dioxide (CO2). The carbon dioxide causes the bread to rise. Because of the structure of the dough the produced gas is hold. A light dough comes into being. After one or two hours the dough has risen enough. The volume has been doubled.
baking process the bottom rises again so that its thickness increases. The edges of the pizza bottom are usually bended upwards.
filling is put later on the bottom. The baking process of frozen pizzas is shorter than the baking process of fresh pizzas. Besides, the filling is already put on the fresh pizza. It is enough to bake the pizzas at a temperature of 230°C for 8 minutes. The bottom has risen and is lightly cooked. The alcohol that is formed by the yeast evaporates at a temperature of 67°C.
In the first place a thin layer of oil or fat is put on the bottom. This avoids the leaking of the moisture of the filling into the relatively dry dough.
Afterwards a layer of tomato puree is sprayed on the bottom. The tomato puree can be bought or produced by cooking tomatoes, mashing them and thickening the sauce with thickening agents. After the tomato puree the other ingredients are put on the pizza. These ingredients can be very diverse. Most ingredients that are put on the pizza are given a heat treatment. This increases the storage life of the pizza. With a heat treatment the enzymes of vegetables are inactivated and the initial germ count is reduced. After the baking process no fresh vegetables can be added.
Grated cheese is not given a heat treatment before it is put on the pizza. The cheese would melt because of the heat which is unwanted for a frozen pizza.
It is important that the ingredients that are not given an heat treatment have a low germ count. Besides, it is important that the whole filling process happens in a very hygienic way.
freezing process also has to happen rapidly. The cooling and freezing process can also be done in an integrated process. The pizzas have to be frozen rapidly because in freezing them ice crystals are formed. When this process happens slowly the water can attach to the ice crystals that are formed. In this way bigger ice crystals are formed. These bigger ice crystals may damage the structure of the bottom of the pizza and the cells of the additives. When the freezing process happens rapidly many small ice crystals are formed. This limits the chance of damage due to the freezing process.
The plastic foil that is used is a shrink-wrap. This shrink-wrap is loosely put around the pizza and sealed. Afterwards this foil is heated for a short time in a shrink tunnel. This causes the foil to shrink around the pizza. Sometimes fresh pizzas are given a protective gas (MAP, modified air packaging), to avoid microbiological growth.