Integrierte Vermeidung und Verminderung der Umweltverschmutzung

Chapter 2
In the UK, the majority of commercial bakers employ the Chorleywood process. In this process,
dough mixing and development take place in a single operation in the presence of an oxidising
agent such as potassium iodate, potassium bromate, or ascorbic acid. This process requires a
high quality wheat flour with a protein content of 12.5 % dry matter together with a high level
of starch damage and hence high water absorption. An oxidising improver, fat or emulsifier, and
extra water and yeast are mixed in at this stage. The whole mixing and development process
lasts between 2 to 5 minutes. All short time systems require high levels of oxidants. The dough
ingredients are mixed together with an intensive energy input and transferred to a hopper which
is sometimes sprayed with oil. The dough is divided into loaf sized pieces. A preliminary
rounding is given to the dough at this stage. The dough is then allowed to rest, first proof, before
being given a final moulding and normally placed into tins. The tins may be sprayed with oil
before filling. The dough is allowed to ferment a second time, second proof, and may be cut
before baking.
2.2.11 Confectionery
2.2.11.1 Biscuits
The principal ingredients used in the manufacture of biscuits are wheat flour, fat and sugar.
Water plays an important role in the biscuit making process but is largely removed during
baking. Baked goods are normally decorated and ingredients like dried and wet fruit, cream and
custard are utilised.
There are two basic dough types are hard doughs and short doughs. Whatever the dough type,
the basic process steps involved in the manufacture of biscuits are dough mixing, formation of
the dough pieces, baking, cooling and packaging. The methods used at each stage vary
considerably depending on the product type. Raw materials are usually received in bulk and
automatically metered into dough mixers. Small ingredients such as salt and sodium bicarbonate
may be weighed and added by hand. The ingredients are blended and, in the case of hard
doughs, mixed to promote a gluten network in the dough. In the case of short doughs, mixing is
such that gluten development is deliberately limited. The formation of dough pieces varies
depending on the biscuit type. Crackers and semi-sweet biscuits are cut from continuous sheets
of rolled hard dough. Crackers require considerable processing as they are built up in a series of
thin layers. Most short doughs are formed by rotary moulding, but soft doughs for biscuits are
usually wire cut. The biscuits are baked, usually in tunnel ovens. The times and temperatures
used vary depending on the product. Ovens may be direct or indirect fired, gas or electric. The
baked biscuits are cooled and packed or transferred for secondary processing, e.g. layering of
cream fillings. Crackers may be oil sprayed immediately after baking. Cooling is typically
achieved by conveying the biscuits around the installation for a set time period.
2.2.11.2 Cakes
The main ingredients used in the manufacture of cake are wheat flour, fat, eggs, sugar, milk
powder, water flavourings and raising agents. Cakes are generally made using either the sugar
batter or flour batter method. In the sugar batter method, the fat and sugar are creamed together
and eggs are added in stages. Several alternate additions of flour and liquid are carried out
throughout the mixing. In the flour batter method, the fat and flour are blended together. The
eggs and sugar are whisked together and then blended into the fat and flour in stages. The
required quantities of liquids are then added in small amounts as mixing progresses.
In continuous mixing systems such as the Oakes and Mondo cake mixers, the ingredients are
given a preliminary mix and then fed in a continuous even stream, into the head of the mixer.
“All in” high speed cake mixing is being increasingly used. In this method, all ingredients
except fruit are added and a fixed amount of mixing is carried out. The fruit is then added in
short bursts.
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