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

110 BARLEY PROCESSING: METHODS AND PRODUCT COMPOSITION
respectively. Thus, it is possible to obtain somewhat normal flour yields by the
roller milling of hulless barley comparable to wheat, but the trade-off is higher
percentages of ash, indicating a higher level of bran particles in the flour, which
will influence color and perhaps baking characteristics. Andersson et al. (2003)
measured the color of the barley flour using grade color factor GCF (units) compared
to wheat flour. The GCF values for straight-run flours of the four barleys
ranged from 4 to 6 whereas values of about 1 to 3 are typical of wheat flour
milled in the same manner. The authors reported that visually the barley flours
appeared to be brighter and whiter than wheat flour. However, when the barley
flours were moistened, they appeared much grayer than wheat flour, possibly due
to activation of enzyme systems.
The chemical composition of the whole barleys (Andersson et al. 2003) was
not unusual other than for the consistency of the data among cultivars (Table 5.4).
The major fiber components of hulless barley, β-glucan and arabinoxylan, were
typical of nonwaxy, hulless Swedish barley grown without environmental stress,
as indicated by the average contents of protein (10.8 to 12.5%) and starch (59.2
to 64.5%). As noted previously, the ash content of the barley flour was approximately
that expected in milled straight-grade wheat flour, being lower than that
of the shorts and bran, with the latter containing the highest level of ash. Protein
was lowest in the flour and similar in the shorts and bran fractions. Starch content
was highest in the flour, since this was derived from endosperm tissue, but was
also relatively high in both shorts and bran, indicating considerable amounts of
endosperm tissue in these fractions also. The β-glucan and arabinoxylan levels
were lowest in the flour, confirming the findings of Izydorczyk (2003). Shorts
TABLE 5.4 Protein, Starch, Ash, β-Glucan, and Arabinoxylan Content of Four
Swedish Whole Hulless Barley and Flour, Shorts, and Bran Produced by Roller
Milling (g/100 g), Dry Matter Basis
Item Protein Starch Ash β-Glucan Arabinoxylan
Whole grain
Mean 11.7 61.2 2.1 3.8 4.8
Range 10.8–12.5 59.2–64.6 1.9–2.4 3.0–4.4 4.4–5.3
Flour a
Mean 8.6 77.1 0.9 1.9 1.4
Range 7.7–9.4 75.8–79.3 0.8–1.0 1.6–2.0 1.2–1.5
Shorts
Mean 14.0 51.5 2.9 5.1 7.1
Range 12.7–14.9 48.2–54.8 2.3–3.3 4.2–5.8 6.1–7.7
Bran
Mean 14.6 39.3 3.6 3.9 10.2
Range 12.2–15.9 34.8–43.9 2.4–4.5 3.0–4.7 8.1–11.8
Source: Andersson et al. (2003).
a Average flour yield = 42.0% (range 36.9 to 47.8%).