Document Type : Original Article
Authors
1
Food Sci. and Tech. Dept., National Research Centre, Dokki, Cairo
2
Food Sci. Dept., Fac. Agric., Zagazig Univ., Zagazig, Egypt
3
Food Sci. Dept., Fac. Agric., Zagazig Univ., Zagazig, Egypt.
Abstract
This study was performed mainly to produce tortilla chips from maize and
sorghum grains. Two varieties of white com (Single cross 10 and triple cross 321) and
two varieties of yellow corn (Single cross 152 and single cross 156) beside Dorado
sorghum were used. Physicochemical changes occurred in starch granules of raw
materials during tortilla chips processing were as follows: dry matter losses (DML)
were 7.00, 6.27, 8.58, 9.84 and 5.98% for WC10; WC321; YC152; YC156 and DS,
respectively. The moisture content of WC10, WC321 , YC152, YC156 and DS
increased during lime-cooking and steeping from 11.42, 9.92, 11.39, 12.77 and 11.09
to 70.5, 69.3, 67.7, 73.79 and 64.43%, respectively. The corresponding water
retention was 233.8, 225.7, 208.6, 281.4 and 181.2% . The obtained masas had the
best machinability properties. The amyloviscosity profiles of grain starches gelatinized
in water revealed that corn starch is more available for gelatinization than sorghum .
Corn starches had a constant viscosity during cooking which increased during cooling.
Sorghum had a highest peak viscosity at 95C followed by decrement due to granules
break down. Gelatinization in lime decreased the temperature of initial viscosity of all
grains and increased !~I?, corn flour viscosity, whereas sorghum viscosity was
decreased. The temp _ (Z'.tU(B or he max. viscosity (peak) decreased from 94.5 to 72C
for com varieties and from :14.5 to 77C for sorghum. The viscosity at 50C was higher
in corn flour gelatinized in water than com and sorghum starches gelatinized in lime
solution.
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