Cereals processing technology
Cereals processing technology
Cereals processing technology
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minimal protein level be maintained. Genetic engineering could allow a higher<br />
proportion of proteins in the malt either to contribute useful enzyme activity or<br />
support yeast nitrogen nutrition.<br />
4.6 Improved cereal quality control<br />
Bio<strong>technology</strong>, cereal and cereal products quality 65<br />
The value of cereals can be improved by better specification of the identity and<br />
composition of cereals in marketing. The major contributions to achieving this<br />
type of value addition are quality assurance programs and enhanced tools for<br />
analysis of products for chemical and microbial contamination and for genetic<br />
identity and purity.<br />
4.6.1 Chemical and microbial purity<br />
The strict application of quality assurance principles can ensure cereal safety<br />
and value. New technologies allow the use of ELISA tests to establish the level<br />
of pesticide residues and DNA-based analysis of microbial contaminants.<br />
4.6.2 Genetic purity<br />
The identity of a cereal genotype defines many of the quality characteristics<br />
such as protein content and grain size. This can define the <strong>processing</strong> value and<br />
optimal end use of a parcel of cereal grain. Protein content can currently be<br />
measured rapidly in the field using near infra-red reflectance (NIR). The<br />
development of rapid genotyping methods would find wide application in the<br />
cereal industry and allow a relatively complete objective description of samples<br />
for commercial valuation.<br />
Distinction of high-value noodle wheats from visually similar wheats of low<br />
noodle quality, and distinction of malting and food barleys with similar<br />
appearance, are good examples of the areas of potential application of this<br />
<strong>technology</strong>. Genetic purity and level of admixture are also important attributes<br />
to assess in commercial trading because of the financial incentive to add lowvalue<br />
grain to parcels of very high value but visually similar genotypes. Rapid<br />
DNA extraction from grain is a key technical requirement for successful<br />
application of these methods.<br />
4.7 Examples of transformed wheat and barley<br />
4.7.1 Desease resistance<br />
The first experiments to engineer resistance in barley focused on barley yellow<br />
dwarf virus. Wan and Lemaux (1994) transformed barley with a construct<br />
containing the coat protein of the virus under control of the constituent 35S<br />
promoter. This approach was based on the results of virus protection
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