Barley for Food and Health: Science, Technology, and Products

HEALTH CLAIMS FOR BARLEY 145
and food scientists. Substitution of barley flour or a barley milling fraction for
part of the wheat flour in yeast bread causes dilution of wheat gluten protein,
which in turn causes weakening of cell structure in bread. Three obvious effects
occur when barley flour is substituted for white wheat flour in breads: reduced
loaf volume, darkened color, and crumb quality reduction. Color and texture
changes are the most obvious effects noted in pasta products. β-Glucans, the
major health-promoting components in barley, have a high affinity for moisture,
adversely affecting the texture and mouthfeel of baked products. Food acceptance
by consumers is strongly influenced by appearance, texture, color, and flavor,
which are all characteristics that can be affected by introduction of an alternative
grain such as barley. A further challenge to product developers is retention of
the beneficial physiological characteristics of β-glucan throughout the processing
steps so that the desired positive health benefits are maintained. This chapter is
a review of current published reports of the inclusion of barley in food products.
Most of the more recent studies focus on overcoming the real or perceived
undesirable effects of barley in various foods. Attention is also directed toward
the vast compositional variation among barley cultivars, particularly related to
starch composition, as noted in Chapter 4. As development of barley cultivars
continues, researchers could be directed toward those genotypes that are desirable
for specific food uses, as well as modification of food-processing methods
to develop superior products while maintaining health benefits of those foods.
HEALTH CLAIMS FOR BARLEY
In May 2006, the U.S. Food and Drug Administration (FDA) finalized a rule that
allows foods containing barley to carry a claim that they may reduce the risk of
coronary heart disease (FDA 2006). Specifically, a food made from eligible barley
sources must contain at least 0.75 g of β-glucan (soluble fiber) per serving.
This specification is based on eating a total of 3 g of soluble fiber daily, and
included as part of a diet low in saturated fat and cholesterol and high in vegetables,
fruit, and grains. Eligible barley products for the claim are whole-grain
barley, pearled barley, barley bran, barley flakes, barley flour, barley grits, and
whole or sieved barley meal. Table 7.1 shows the required total and soluble
dietary fiber specified for these products. The barley sources are required to have
been produced from dehulled or hulless clean, sound barley grain by standard
dry milling processes, which may include steaming or tempering. Note that this
ruling does not include barley β-glucan extracts produced through wet milling
processes. The rationale for excluding wet milling–processed extracts was that
the physiochemical properties of fiber and other components may be altered
by the extraction processes. This possibility may be changed in the future by
standardization of those processes, as discussed by Brennan and Cleary (2005).
Most of the allowable dry-milled barley products specified in the FDA ruling
are defined in the American Association of Cereal Chemists (AACC) glossary of
barley terms, which is published in the AACC Approved Methods (AACC 2000),