Baking & Snack - December 2003 - 48

INGREDIENT TECHNOLOGY

On the market
Active dry yeast - This yeast comes in granular forms
or small beads. It has a good level of stability at ambient temperature. It needs rehydration under controlled
conditions and releases a little glutathione that acts as
a dough conditioner.
Compressed yeast - For economic and practical
reasons, this is the most widely used form of bakers yeast. Compressed yeast requires no particular
precautions and disperses in cold water without
any problems.
Free-flowing, frozen yeast - For applications such as
frozen dough with a shelf-life longer than two weeks, it
is necessary to use yeast with lower dry-matter content
(approximately 75%). Despite its free-flowing appearance, this form offers the functional characteristics of
compressed yeast.

Instant yeast - Dried in a fluidized bed system, instant yeast is vacuum packed; the vacuum guarantees
the stability of the product at ambient temperature.
Partly used bags should be carefully closed and stored
at cold temperature.
Liquid yeast - Also called cream yeast, this form
can be automatically pumped from truck tanks into
a bakery's temperature controlled yeast tanks. From
these tanks, yeast is automatically metered into mixing
stations, thereby eliminating the need to hand scale.
It is evenly dispersed in the dough during mixing. Its
stability is guaranteed by careful monitoring of the
storage temperature. Installations are "tailor-made" to
each user. Strict cleaning and disinfection standards
must be observed to maintain this type of yeast in
optimum condition.

different ranges of sugar. Instant dry yeasts are designed
either for low (0%) to mid-range (18%) sugar levels or
for sugar levels over 18%.

altered by production methods and deteriorates significantly as frozen storage time increases. Frozen doughs
must not only make it into the freezer with good fermentation viability, but they also must withstand freeze/thaw
cycles during warehousing, shipping and frozen storage
at distribution and sales locations.
As Lallemand/American Yeast Division, Northlake, Ill.,
explained in its Baking Update (Vol. 1, No. 18), the stability of yeast in a frozen dough, a quality called cryoresistance, is key to obtaining good results. This resistance
seems to be partly associated with the presence of trehalose, a cryoprotective compound found in yeast. High
levels of trehalose can be induced by choosing a cryoresistance strain for yeast production and strictly controlling growth conditions. Since high trehalose levels (up to
15%) mean lower levels of protein and, thus, lower levels
of enzymes, the gassing power of cryoresistant yeast is
usually diminished. Yeast with high cryoresistance tends
to stay dormant longer and activates slowly when it is
mixed into a dough. So, a trade-off exists between a
quick-starting yeast with high initial gassing power but
low cryoresistance vs. a slow-starting yeast with lower
gassing power but excellent cryoresistance.
The longer the dough will be held in frozen storage,
the more important it is to choose yeast with good
cryoresistance. Most frozen dough products are made
using a short, no-time dough process and have fast
turnover, typically less than two weeks of frozen storage. For such products, yeast cryoresistance is less important. When storage time stretches out to three to
six months, however, a special yeast strain might be
more important. Critical applications, such as frozen
croissants and laminated pastries, may also require a

FOR FROZEN DOUGHS. The frozen dough and frozen
pizza categories have been among the fastest growing
areas in the bakery market. Obviously, this has presented
new challenges to formulators because the quality and
stability of frozen dough is greatly influenced
by its ingredients and processing
conditions. Yeast selection plays
an important role in
the production of
frozen doughs
since yeast activity can be

ᮤ To extend the shelf life of baked foods, many bakers rely on mold inhibitors, but these additives can interfere with yeast activity. Encapsulation of the
inhibitor allows release later in baking, after yeast has done its job.
BALCHEM ENCAPSULATES

48 / BAKING & SNACK / December 2003

Baking & Snack - December 2003

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