Barley for Food and Health: Science, Technology, and Products
Barley for Food and Health: Science, Technology, and Products
Barley for Food and Health: Science, Technology, and Products
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4 <strong>Barley</strong>: Genetics <strong>and</strong> Nutrient<br />
Composition<br />
INTRODUCTION<br />
In<strong>for</strong>mation presented in Chapter 2 describes the complexity of the barley plant<br />
<strong>and</strong> kernel, the growth of which is controlled by the barley genome from germination<br />
to maturity. The inheritance of certain characteristics is critical to the<br />
problem of breeding barley <strong>for</strong> food or any other desired end uses. Perhaps the<br />
importance of the genetic code is emphasized when it is recognized that all cultivated<br />
barley used <strong>for</strong> feed, malt, or food is dependent on the tough rachis that<br />
is controlled by the brittle genes, Btr1 <strong>and</strong> Btr2 , found on chromosome 3(3H).<br />
Cultivated barleys are homozygous recessive <strong>for</strong> either one or the other gene<br />
or <strong>for</strong> both genes that produce a tough rachis (Harlan 1978). Without a tough<br />
rachis, harvesting mature barleys seeds would be difficult because this characteristic<br />
prevents scattering of seeds by any number of natural events, such as wind<br />
or rain.<br />
There are several characteristics under genetic control that can be introduced<br />
selectively into barley to influence or dictate nutrient composition. Additionally,<br />
genetic selection can be employed to incorporate value-added attributes such as<br />
ease of harvesting or processing, product appearance, taste, <strong>and</strong> health-promoting<br />
factors of barley foods. Although it is not possible to control completely the<br />
level <strong>and</strong> occurrence of all nutrients in barley, certain genes can be inserted or<br />
expressed in the genome, producing minor to major influences on composition.<br />
Nutrients are unevenly dispersed in the various parts of the kernel, some being<br />
more concentrated in one area while others are concentrated in other parts. The<br />
location <strong>and</strong> concentration of the nutrients in the kernel have major implications<br />
in nutrient availability, processing methods, <strong>and</strong> in food preparation. Nutritional<br />
parameters of barley are generally reported as averages, when in reality barleys<br />
differ as much or more in nutritional characteristics as in morphological<br />
characteristics. The amounts <strong>and</strong> types of the various nutrients are controlled by<br />
<strong>Barley</strong> <strong>for</strong> <strong>Food</strong> <strong>and</strong> <strong>Health</strong>: <strong>Science</strong>, <strong>Technology</strong>, <strong>and</strong> <strong>Products</strong>,<br />
By Rosemary K. Newman <strong>and</strong> C. Walter Newman<br />
Copyright © 2008 John Wiley & Sons, Inc.<br />
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