Agriculture Reference
In-Depth Information
ingredients. It is likely that in countries other than the UK, enrichment of white
fl our is not required by law and in that case it too could be classed as a natural
material.
Egg is a highly functional ingredient supplying key functionality based on
foam formation and stabilisation, emulsifi cation of fat and oil, and contributing to
the structural properties of products such as cakes. Egg would be regarded as a
natural ingredient as the only processing it undergoes is one of pasteurisation to
ensure safety from a microbiological point of view. However, as mentioned in
Section 14.1, the egg would have to be declared as 'pasteurised egg' on the product
label. Egg is used in a range of bakery products including cakes, pastry, buns and
speciality breads. It is included to obtain numerous benefi ts including volume,
texture and fl avour as well as richness owing to its naturally high lipid content.
Some of the egg functionality can be fully or partially replaced by more functional
ingredients such as emulsifi ers. The availability of new lipases, which can modify
naturally occurring lipids in key raw materials such as egg, to generate more
active derivatives has presented the industry with a practical route to achieve the
important functions of emulsifi ers and this is discussed later in the chapter.
It has been common practice to include a minimum level of a high melting
point fat in no-time dough development such as found in the Chorleywood Bread
Process (Cauvain 1998). Cake production also relies heavily on shortening with a
controlled ratio of liquid to solid fat, the solid fat consisting of small needle-like
crystals which contribute to good whipping properties in the batter and gas bubble
stabilisation.
The production of laminated products such as puff pastry is only possible
with the use of shortening, which has similar fi rmness to the dough paste. The
shortenings used in these products have usually come from animal and vegetable
sources that have undergone considerable processing (refi ning, bleaching and
deodorising) to ensure a bland tasting, almost colourless product. Further changes
to improve functionality have been achieved using chemical reactions such as
hydrogenation or inter-esterifi cation reactions, both processes resulting in a more
stable product with improved functional properties.
However, the fats and shortenings produced in this manner would contravene
the defi nition of 'natural' as stated above. The pressure to utilise more natural fats
has come from the need to remove trans fats from the diet and one route to achieve
this is to prepare shortenings from natural fats such as palm, mango kernel and
mahua fats that have no trans fatty acids (Yella Reddy and Jeyarani 2001). The
individual fats are fractionated by dry fractionation to obtain a high-melting
fraction or a two-stage solvent fractionation. By combining these different
fractions in specifi c ratios, a shortening with similar melting properties to those of
commercial hydrogenated shortening for cakes and biscuits is claimed (Yella
Reddy and Jeyarani 2001).
Cake production, and to some extent bread production, is now being carried
out using oils such as rapeseed, soybean and corn instead of hard fats. The
traditional method of extracting oil from plants has been to use physical processes
that involve crushing using a screw or ram press, but a more recent method
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