Baking & Snack - July 2009 - 59

DAIRY INGREDIENTS

branes used during ultrafiltration.
Although ultrafiltration is the preferred method for extracting MPC,
it also can be produced by precipitating the proteins out of milk or by
dry-blending the milk proteins with
other milk components. Depending
on how MPC is produced, costs may
vary and, more important, functionality may differ.
Commercially, MPCs, which are
white to light-cream-colored dry powders, range in protein levels starting at
about 42% and going to 85%. As the
protein content of MPCs increases,
the lactose level decreases. For example, MPC42 is 42% protein and 46%
lactose. MPC80 contains 80% protein and 5% lactose. For comparison,
skim milk powder (SMP) contains
about 35% protein and 52% lactose.
Although they share similar form and
function, MPC and SMP act differently depending on the application.
WHEY IN. As mentioned, whey is
the by-product of cheesemaking
and has long been viewed simply as
something that was disposed. Whey
has come a long way, and in some
instances, cheese is produced for the
sake of making whey.
Today, whey is processed into a
number of food-grade ingredients.
Its valuable protein components
are isolated and used for both functional and nutritional fortification of all types of foods, including
baked foods.
Now a new by-product is gaining recognition in the baking world
- whey permeate - or, what is left
over after whey has been processed
into specialty protein ingredients
such as WPC, which ranges in protein content from 34 to 90%, and
whey protein isolate (WPI), which
provides 90% or more protein.
During ultrafiltration and diafiltration, whey proteins are retained
by the filtering membrane because
of their larger size and processed
into WPC and WPI. Lower molecular weight whey components, such as

BAKING & SNACK / July 2009

ᮢ Whey permeate allows for a reduction of more expensive ingredients in
applications such as cookies. Cookies
containing permeate are crispier, with
a shorter texture and more browning
and spread.

lactose and various minerals including calcium and phosphorus, pass
through the membrane and become
the permeate stream. Once moisture
is removed from the liquid permeate
stream, an off-white, free-flowing
powder with a mild dairy flavor
remains. After any residual protein
is removed from this powder, along
with a small amount of lactose and
minerals, the remaining powder is
whey permeate.
"Whey permeate can deliver enhanced functionality and organoleptic characteristics that make it a useful
and versatile bakery performer," said
K.J. Burrington, dairy ingredient applications coordinator at the Center
for Dairy Research at the University
of Wisconsin, Madison, WI.
The composition of whey permeate
varies by milk source, cheese type and
processing conditions. Permeate contains only trace amounts of protein;
however, many commercial specifications list protein content around 3.5
to 5%. This discrepancy is due to the
dairy industry's tradition of calculating protein contents by testing for total
nitrogen, which, in the case of permeate, is largely non-protein nitrogen
rather than true protein.
"The main component of whey
permeate is lactose," Ms. Burrington
said. "This lactose contributes to an
enhanced surface browning in many
baked foods."
Lactose, a reducing sugar, enters
into browning reactions with amino
acids (Maillard browning). It also
caramelizes readily under the influence of oven heat. Although a sugar,
lactose is not very sweet. In fact, it
has a sweetening power of only 16
compared to 100 for sucrose in a 1%
aqueous solution.

Lactose is also less soluble than
either glucose or sucrose, and crystallizes more readily than either of
these sugars. It is unfermentable by
yeast and thus survives the dough
fermentation unchanged and undiminished. Bakers have long added
small amounts of lactose to doughs
and batters, either directly or indirectly through the addition of dairy
ingredients. Now whey permeate is
another one of those indirect options.
"We are also discovering that the
minerals in whey permeate provide a
salty perception, while only contributing a minute amount of sodium,"
she said.
Permeate contains less than 1%
sodium and, thus, can positively influence the Nutritional Facts label. "In
fact, in some baked foods, it has been
possible to not add any salt to the
application and still have a tasty product," Ms. Burrington pointed out.
Further, whey permeate provides
a cost savings when it substitutes
for more expensive ingredients.
Research shows that a significant
amount of permeate (5 to 8%)
can be used in muffins, scones or
cookies, resulting in products of
similar or superior quality to those
formulated using nonfat dry milk.
For example, in chocolate chip cookies, flour and egg are kept constant,
but using 6% whey permeate allows
for a reduction in more expensive

Baking & Snack - July 2009

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