physicochemical
Contents of 39(1 & 2) 2011 - acharya ng ranga agricultural university
Contents of 39(1 & 2) 2011 - acharya ng ranga agricultural university
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PARIMALAVALLI and KAVITHA<br />
dough ball was rolled and flattened to chapathi and<br />
roasted on a preheated non-stick hot plate for 20<br />
seconds on one side, 10 seconds on an other side,<br />
and held over flame until complete puffing occurred<br />
(Rao and Bharathi, 1996).<br />
SUBJECTS: Six healthy non – medicated women<br />
aged from 40 to 50 years were selected and consent<br />
was obtained from all the selected subjects. The<br />
fasting blood glucose level of the group was within<br />
the normal range (94.33±5.01 mg/dl) and gave normal<br />
2 h response to glucose tolerance test. Glucose (50g)<br />
was administered for conducting Glucose Tolerance<br />
Test on the first day. After the GTT, test foods such<br />
as broken wheat porridge, whole wheat flour porridge,<br />
whole wheat flour chapathi were given on the second,<br />
third and fourth day respectively. Blood samples were<br />
drawn before and at 30, 60, 90 and 120 min after<br />
consumption of the test foods. The blood samples<br />
were collected through finger prick using a hypodermic<br />
needle. Each blood sample was placed on a test strip<br />
which was inserted into a calibrated glucometer<br />
(Optimum/one touch) which gave direct readings after<br />
5 seconds.<br />
CARBOHYDRATE BASIS FOR GLYCAEMIC<br />
INDEX (GI) DETERMINATION<br />
GI of foods such as broken wheat porridge,<br />
whole wheat flour porridge and whole wheat flour<br />
chapathi was measured. The test foods contained<br />
significant amount of available carbohydrate that<br />
means total carbohydrate minus dietary fiber. A 50 g<br />
available carbohydrate load had been proposed as a<br />
reference amount for GI testing.<br />
CALCULATION OF GLYCAEMIC INDEX<br />
Incremental Area Under Curve (AUC) was<br />
recommended by the Food and Agriculture<br />
Organization (1998), and it is calculated as AUC using<br />
the incremental AUC, ignoring area under the baseline.<br />
Assuming that at times t 0<br />
, t 1<br />
, …. t n,<br />
the blood glucose<br />
concentrations are G 0<br />
, G 1<br />
, ….G n<br />
, respectively:<br />
AUC =<br />
x=1<br />
Ax<br />
<br />
n<br />
where Ax is the AUC for the xth time interval, and<br />
the xth time interval is the interval between times<br />
t x-1<br />
and t x<br />
.<br />
The results were expressed as mean and<br />
standard deviation.<br />
RESULTS AND DISCUSSION<br />
Glucose tolerance test was carried out in the<br />
selected healthy women (n=6). The blood glucose<br />
level was estimated in the empty stomach at zero<br />
hour, after that, broken wheat porridge was given.<br />
After 30, 60, 90 and 120 minutes, the blood glucose<br />
levels were recorded. The next day, whole wheat flour<br />
porridge was served and the same procedure was<br />
followed. The mean blood glucose levels were shown<br />
in figure – 1.<br />
Figure 1. Mean blood glucose concentration of wheat based foods with reference to processing<br />
Blood Glucose Concentration<br />
(mg/dl)<br />
160.00<br />
140.00<br />
120.00<br />
100.00<br />
80.00<br />
60.00<br />
40.00<br />
20.00<br />
0.00<br />
140.50<br />
127.00<br />
123.00<br />
117.00<br />
94.33 120.00<br />
98.00 96.50<br />
109.80<br />
94.50<br />
92.30<br />
96.00<br />
81.00 83.80<br />
86.50<br />
Fasting 30 min 60 min 90 min 120 min<br />
Time (Minutes)<br />
Glucose<br />
Broken w heat<br />
porridge<br />
Whole w heat flour<br />
porridge<br />
The mean fasting blood glucose level of the<br />
selected healthy women was 94.33+5.01 mg/dl and<br />
it was increased to peak level 140.5+ 6.47 mg/dl<br />
within 30 minutes after ingestion of 50g glucose. The<br />
blood glucose level was declined to 127+5.22,<br />
117+3.89 and 86.5+12.82mg/dl at 60, 90 and 120<br />
minutes respectively. The glucose concentration after<br />
ingestion of 50g carbohydrate from the broken wheat<br />
porridge was increased to 120+5.83 mg/dl within 30<br />
minutes and 109.8+5.12 mg/dl at 60 minutes and<br />
slightly increased to 96.5 ± 6.56 mg/ dl at 120 minutes.<br />
The glucose concentration after ingestion of 50g<br />
44