Chemistry Reference
In-Depth Information
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Time after mixing (min)
Control
Combination bacterial protease and hemicellulase
Fig. 7.6
Wafer batter viscosity with and without bacterial protease and endoxylanase
texture. Due to reduced water quantity, less water needs to be evaporated, resulting in a more
dense structure whereby the wafers will increase in crunchiness and become more firm. The
application of bacterial protease and xylanase has become widely accepted.
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In 2004, a patent by Nestec S.A. was published describing the use of a thermalstable
α-amylase to manipulate textural attributes of flour-based food products like wafers, without
resulting in an increased batter viscosity. Furthermore, the stickiness of the batter is not
changed and the batter remains easily processable.
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7.7
USE OF ENZYMES IN WHEAT FLOUR TORTILLA
Tortillas are unleavened, flat, round breads made from wheat or corn. They are an important
part of the diet in Mexico and Central America and a fast increasing part of the diet in North
America. In fact, currently in the USA there is already more wheat flour used for tortilla
manufacturing than for the production of white bread.
Flour tortillas are made of wheat flour, water, shortening, and salt, preservatives, leavening
agents, reducing agents and emulsifiers. The bread has a circular, flat shape and usually varies
in diameter from 100 to 700 mm and in thickness from 1 to 5 mm.
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Tortilla dough is gluten
structured and most of the tortillas contain chemical leavening agents. During mixing, small
air bubbles are formed and distributed evenly throughout the dough.
The texture of tortillas depends upon the retention of gasses by the gluten matrix.
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Good
quality flour tortillas are soft, opaque and flexible without cracking when folded.
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Tortilla staling can be significantly reduced by the addition of a low activity level of
bacterial amylases. Also the flexibility will significantly improve by the addition of bacterial
amylase. In the past, it was proposed that bacterial amylase will affect the structure of starch
through hydrolysis of the amylopectin, and the anti-staling effect could be possibly due to
the interference of the hydrolysis products with amylopectin retrogradation.
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Recent insights have shown that staling of tortillas involves the starch in the amorphous
phase and does not significantly interfere with the amylopectin crystallization. It is proposed
