physicochemical

GLYCAEMIC INDEX AND GLYCAEMIC LOAD OF WHEAT BASED FOODS
carbohydrate from the whole wheat flour porridge was
123+5.09, 81+8.36 and 92.3+4.37 mg/dl at 30, 60
and 120 minutes respectively. Moreover the peak
values were observed at half an hour after ingestion
of broken wheat porridge and whole wheat flour
porridge. Similar results were observed by Asna et
al. (2006) who stated that the GR at 30 min after
consumption of dumpling meals were comparatively
higher than the two roti meals. Thereafter the levels
showed a reducing trend at one hour, the mean blood
glucose value (81 mg/dl) of whole wheat flour porridge
recorded a lower response when compared with
broken wheat flour porridge (109.8 mg/dl). Broken
wheat slows digestion and absorption of carbohydrate,
hence it reduces the glucose response.
Foods with an intact botanical structure tend
to have lower GI values, as the starch is protected
from enzymatic degradation by the outer layer of the
grain kernel (Juntunen et al. 2002). Particle size of
flour affected the quality and starch gelatinization
(Lowerance et al. 1986). If the particle size of flour is
big, the flour cannot absorb the necessary water, and
medium particle size increases the water absorption
of flour (Pomeranz et al. 1988). Granfeldt et al. (2005)
revealed that the factors such as variety, cooking
and processing may affect a food’s GI. The
researchers found that the GI of wheat, maize and
oats increased from whole grains (lowest GI), cracked
grains, course flow to fine flour (highest GI). Methods
of cooking affect the digestibility of wheat starch.
Gelatinization may be one of the factors that
determine the rate of starch digestion (Susan et al.
1987).The mean blood glucose response of the test
foods in normal women is given in the Figure-2.
Figure 2. Mean blood glucose concentration of wheat based foods with reference to cooking
Blood Glucose Concentration
(mg/dl)
160.00
140.00
120.00
100.00
80.00
60.00
40.00
20.00
0.00
140.50
126.83
127.00
117.00
105.0
98.33 123.00 118.00
112.17
96.00
92.3
94.33
83.80
86.5
81.00
Fasting 30 min 60 min 90 min 120 min
Time (Minutes)
Glucose
Whole w heat flour porridge
Whole w heat flour chapathi
The glucose concentration after ingestion of
50g carbohydrate from the whole wheat flour chapathi
was increased to 126.8+5.19 mg/dl within 30 minutes
and 118+3.52 mg/dl for 60 minutes. The glucose
concentration was 112.16+3.31 mg/dl and 105+5.44
mg/dl for 90 minutes and 120 minutes respectively.
The mean values obtained for different products are
presented in table-1
Table 1. Glycaemic index of wheat based foods
Food Product Quantity of Glycaemic Index (GI) Category*
available CHO
Broken Wheat Porridge 50 33.74±11.49 Low
Whole Wheat Flour Porridge 50 45.26±7.26 Low
Whole Wheat Flour Chapathi 50 59.86±10.9 Medium
* www.glycemic index.com
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