Cereals processing technology

58 Cereals processing technology
4.4.2 Cereals and animal nutrition
The major requirements of animals differ depending on whether they are
monogastric or ruminant animals and the potential of biotechnology to improve
the nutritional values for these two classes of animals differs. Ruminants have a
much greater capacity to digest cereal fibre effectively. Soluble fibre
components may also be important. For example, the -glucans of barley limits
the use of this cereal in the diet of chickens because of its adverse impact on
nutrient utilisation.
4.4.3 Cereals in aquaculture
The increasing shortage of seafoods (declining fish stocks in the oceans and
increasing human population) indicates great potential for enhanced use of
cereals in aquaculture diets used in fish farming (Sarac and Henry 1998).
Cereals provide a very cheap option and if biotechnology can be used to enhance
the nutritional value of cereals as a component of aquaculture diets we can
expect wide-scale use of cereals for the production of aquaculture products.
Cereals may have an important role as a binder in aquaculture feeds.
Improvement of protein and lipid composition by genetic engineering may
produce more useful cereal aquaculture feeds.
4.5 Improved processing qualities
The quality requirement of cereal processors may be complex as indicated for
barley in Table 4.3. This table lists a few of the characteristics defined as
requirements of a barley for use in malting and brewing. Establishing
opportunities for quality improvement requires a knowledge of the processes
used to convert cereals into end products.
Table 4.3 Barley quality characteristics required for brewing (Henry 1990)
Character Requirement
Grain colour Bright, white aleurone
Grain size Plump grains, 90% above 2.5 mm, as little as possible
below 2.2 mm
Protein content Optimum 10.5%–11.5% (dry basis)
-glucan content Low – maximum and minimum not defined
Husk Minimum required for brewing
Dormancy As little as possible (but no pre-harvest sprouting)
Rate of modification As fast as possible (steeping and germination maximum
110h)
Malt extract As high as possible (only too high if protein on husk
becomes limiting)
Malt enzymes As high as possible (minimum requirements for diastatic
power and -glucanase)