Baking & Snack - April 2005 - 74

After Amylose Settles
As mentioned, it is the retrograding of amylopectin during storage of a baked food
that is responsible for firming during shelflife. Certain enzymes are able to reduce
starch retrogradation by modifying the starch.
"Enzymes are biocatalysts with narrowly defined specificity and action patterns
that can be used to improve loaf volume, crumb structure, dough stability,
tolerance, taste, flavor and crumb softness," said Jan van Eijk, research director,
Lallemand, Montreal, QB. "Amylases that break down gelatinizing starch during
baking are particularly effective anti-staling agents."
The heat stability and action patterns of amylases are important parameters
for their performance. "Starch granules are in practice only susceptible to
enzyme attack during and after gelatinization, which means the enzymes need
to be heat stable in order to have any effect," explained Dave Kappelman,
technical director, bakery, Danisco USA, New Century, KS. "Enzymes with a low
thermostability such as standard fungal alpha-amylase have only a couple
of minutes in which to act, while bacterial alpha-amylase has two to three
minutes more at an elevated temperature."
It is believed that alpha-amylase acts on amylopectin, decreasing its molecular
weight. This reduces the amount of amylopectin available for retrogradation,
thus slowing the rate of firming. In addition, the branched chain fragments of
lower-molecular-weight dextrins produced by the alpha-amylase interfere with the
alignment of the outer chains of the intact amylopectin.

is one of the components in baked foods
responsible for staling, because firmness, or
loss of softness, correlates to staling.
"Other factors, however, also have an
impact on the firming of baked foods,"
said Dave Kappelman, Danisco's technical manager, bakery. "Particularly, the
distribution of water between protein and
starch plays an important role."
The retrogradation of starch, which is a
water distribution issue, is usually the
main contributor to time-determined changes in crumb

"Basically, good anti-staling amylases produce dextrins of a particular size, a size
that effectively interferes with the retrogradation of amylopectin and/or cross linking
of the gluten and starch phases," Mr. Kappelman said.
Amylases are not the only enzymes that slow staling. In recent years, scientists
have been able to use a variety of enzymes including oxidases, proteases and
lipases to retard staling. "A new dough conditioner based on a lipase enzyme with
broad substrate specificity is able to unlock the dough strengthening potential of
natural flour lipids," reported Mr. van Eijk. "The modification of polar flour lipids
by phospholipase and glycolipase activity greatly improves the loaf volume and
crumb structure of bread and allows the baker to save costs by reducing the level of
emulsifiers currently used in baked foods."
Just as emulsifiers are bakery application specific, so, too, are enzymes.
Furthermore, some enzymes can improve crumb softness considerably but tend to
give the "wrong" kind of softness, resulting in a gummy crumb that lacks resilience.
"The use of enzymes to extend shelf life in bakery applications that contain
higher levels of sugar and fat has historically been less effective than in bread and
bun applications," said Mr. Kappelman. "However, a new enzyme system is able to
provide excellent crumb softness and resiliency without imparting gumminess or an
overly moist texture in these indulgent products. The ingredient is easy to formulate
into a variety of sweet goods applications because of its flexibility in use level,
whereas other enzyme systems may require exact use levels."

softness. Hence, emulsifiers to the rescue.
"Emulsifiers combine with the straightchain starch molecules inside the starch
granules and keep them from diffusing
out so that they do not contribute as much
strength to the initial crumb set," Mr. Van
Eijk noted. "However, emulsifiers do not
have as much effect on the branched starch
that causes crumb firming during storage
and do not slow the moisture migration
from crumb to crust."
Larry Skogerson, vice-

president and technical director of American Ingredients Co., Kansas City, MO,
explained further, "The main reasons for
using emulsifiers in baked foods are for
dough conditioning, dough strengthening
and crumb softening. They provide a silky
texture in bread and bread-style products,
and definitely improve slicing ability.
"It's important that formulators keep in
mind that emulsifiers are application specific," he continued. "What texturizes yeastleavened bread is very different from what
works in a chemically leavened cake."
In general, fat-based ingredients are excellent emulsifiers in bakery products. "Monoglycerides are one
of the more popular ingredients used in emulsifier systems," said Mr.
Skogerson. "In yeastraised products, the
monoglycerides
should be hydrated to provide
functionality. Thus,
they must be readily
dispersible in dough systems.
Pre-hydrated
monoglycerides
eliminate any concerns regarding

ᮤ The eating quality of sandwiches depends
on the freshness of the bread or bun used.
Kerry Ingredients

76 / BAKING & SNACK / April 2005

Baking & Snack - April 2005

Table of Contents for the Digital Edition of Baking & Snack - April 2005