Agriculture Reference
In-Depth Information
Betaine has been used as a dietary feed supple-
ment in animal nutrition for more than 50 years.
Slow et al. (2005) reported that the primary
source of betaine in the New Zealand human diet
was from cereal grains and the primary form was
glycine betaine. Earlier data from Waggle et al.
(1967) shows that wheat betaine is concentrated
in wheat bran and wheat germ. However, levels
can vary depending on cultivar and possibly envi-
ronmental factors.
Likes et al. (2007) tested several mill streams
for betaine and choline content, and confi rmed
that the bran and germ fractions are richest in
these components. Betaine levels in a mill stream
generally refl ect the bran content. This data rein-
forces the nutritional value of whole wheat and
suggests that incorporation of whole-wheat prod-
ucts into the diet would reduce risk of many
chronic diseases.
cesses, and the rapid growth of ethanol produc-
tion from cereal starch.
The concept of an industrial wheat “class”
involves combining several genetic features that
have not been combined before. First, industrial
wheat would be targeted to nonfood uses (animal
feed and fermentation), so the protein quantity
and function would be reduced in importance.
Indeed, protein content could be suppressed and
quality ignored in this context. Starch content
should be maximized, so low-protein cultivars
would be favored. Second, high agronomic yield
would be critical to achieve suffi cient profi t per
unit area to compete with higher-value food
wheat. Finally, the starch should be waxy, since
there is growing evidence to suggest that waxy
starch will convert to sugars and ferment to
ethanol in approximately 70% of the time as
normal cereal starch (see the following section:
“Soft and waxy wheat for ethanol production”).
This offers ethanol producers a signifi cant pro-
ductivity gain over normal starch, refl ecting com-
parable value with other wheat types or even
maize, which offer higher agronomic yield.
INDUSTRIAL WHEAT
Since wheat is so well recognized for its unique
protein functional properties, its value as a human
food often precludes its consideration for indus-
trial applications. Such applications usually favor
underutilized materials, such as co-products from
other processes. Wheat co-products from the dry-
milling process are more often used in animal feed
rather than in industrial processes. Wet-milling
of wheat for separation of gluten and starch frac-
tions results in products used in industrial, feed,
and food products. However, wheat cultivars are
typically not bred for industrial uses.
The 2004 Wheat Summit held at Kansas State
University reviewed options to invigorate and
expand the wheat industry, including ideas to
pursue new uses (Table 22.1). At that time,
highest prioritized new uses of wheat were protein
quality characteristics, low PPO activity, or high
antioxidant content—all related to food applica-
tions. Industrial uses were not ranked highly at
that time. However, in only 3 years, the landscape
has changed and industrial potential is being reex-
amined. This has come about with the develop-
ment of waxy wheat cultivars, new fi ndings about
the value of waxy starch in fermentation pro-
Breeding wheat for nonfood uses
Two types of wheat might have application in
industrial settings, namely low-phytate and waxy
types. Phytic acid or phytate (myo-inositol-
1,2,3,4,5,6-hexakisphosphate, or Ins P6) is the
most abundant storage form of phosphorus in
seeds, but it is indigestible by humans and non-
ruminant livestock. High phytate consumption
can actually contribute to mineral depletion and
defi ciency (Raboy 2002). In humans and nonru-
minant animals, consumption of grain with
reduced phytate levels can improve the absorp-
tion of essential micronutrients. Guttieri et al.
(2004) identifi ed a mutant designated Js-12-LPA
that was characterized as having high levels of
seed inorganic phosphate (HIP) and reduced
phytate. The low-phytic-acid (LPA) trait had
little effect on processing quality of hard wheat,
but there was some detrimental effect on soft
wheat quality attributes (Guttieri et al., 2006a).
Grain yield was negatively affected in some
genetic backgrounds; the effects, however, were
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