Biology Reference
In-Depth Information
may have been responsible for this effect because the barley products had
four times more
b
-glucan than the oat test meals. Unlike the effect of particle
size noted in wheat bran products (
Holt & Miller, 1994
), in oat and barley
products, the
b
-glucan effect surpassed the particle size effect.
A difference in glycemic response has been reported for porridges made
of steel cut oats and rolled oats. Steel cut oats resulted in lower glycemic
response suggesting that the degree of processing may also play an important
role in the glycemic response of oats (
Gonzalez & Stevenson, 2011
)
. Differ-
ence in the processing method during extraction of oat
b
-glucan could in
turn affect its viscosity and the resultant glycemic response.
Panahi,
Ezatagha, Temelli, Vasanthan, and Vuksan (2007)
compared an enzymati-
cally extracted
b
-glucan and
b
-glucan extracted by aqueous method and
found that the former was more effective in preserving the viscosity of
the
b
-glucan thereby resulting in a 19.6% reduction in the glucose AUC
compared to the latter
b
-glucan.
6.3. Rye
Increased blood glucose and insulin are risk factors for metabolic syndrome
in adults. Subjects showing symptoms of metabolic syndrome were assigned
to a diet containing rye bread and pasta or oat and wheat bread and potato for
12 weeks (
Laaksonen et al., 2005
). There was no difference in the glucose
measurements after an on oral glucose tolerance test in the subjects at the end
of the intervention period. However, there was a small improvement in
their insulin sensitivity following the rye bread consumption, probably
due to increased pancreatic
b
-cell function. In an earlier study by the same
group comparing different types of rye bread such as endosperm rye bread,
traditional rye bread, and high-fiber rye bread prepared by sourdough fer-
mentation, the blood glucose responses to the rye breads were similar to the
wheat bread
(
Juntunen, Laaksonen, Autio, et al., 2003; Juntunen,
Laaksonen, Poutanen, et al., 2003
). However, the insulin responses to rye
breads were significantly lower than the wheat bread. The fiber content
was different between the four test breads with 2.7 g in wheat bread,
6.1 g in the endosperm rye bread, 15.2 g in the traditional rye bread, and
29 g in the high-fiber rye bread. There was no obvious effect of difference
in fiber content between the rye breads, probably because the difference was
mainly in the insoluble fiber levels rather than the soluble fiber content. The
difference observed between wheat and rye breads was thus attributed to
their different structure of the food matrix resulting in a compact structure
in rye compared to a gluten-mixed network of starch forming a continuous
phase in the wheat bread. Some differences in the particle size of the bread
