Baking & Snack - June 2020 - 84

FREEZING

Breads and cakes effectively insulate themselves from rapid changes
in internal temperature," observed Chris Johnson, business development director, Praxair, Inc., a Linde company. "Increasing or decreasing
the diameter or thickness of a baked product, even slightly, can have a
dramatic impact on the time required to freeze."
Overall, he added, baked items require a consistent temperature before entering an efficient freezer to achieve maximum quality. However,
some filled products like empanadas present freezing challenges.
"If they're frozen too quickly, they may crack due to the differing contraction rate between the dough and the filling," Mr. Johnson explained.
"Freezing too slowly can allow for moisture migration between the filling and the dough and/or ice crystal growth within the dough that damages the texture."
Bakers should audit the freezing process through in-plant testing or
in a food lab to understand the specific heat modes and to determine
whether to use mechanical chilling, nitrogen or carbon dioxide (CO2).
Using the incorrect freezing method, for instance, might kill the yeast
and turn frozen dough into inert hockey pucks.
"Yeast-raised products have some of the lowest stabilities of any frozen foods, and along with the yeast dying, you also have the issue of
your gluten structure weakening," noted Lars Soderman, sales director,
Scanico, a Middleby Bakery company. "A bread baked from a dough
that is frozen will most likely not have the volume a fresh-dough bread
would have. Even though you have increased your yeast, the gluten
structure will still be weaker and will not allow the bread to expand in
the way a fresh dough would."
Over-freezing typically doesn't cause product damage. Rather,
Mr. Johnson said, it just wastes energy. A slow freeze, however, will tend to
dehydrate baked goods and result in freezer burn or a dry spot or section
on a bread or roll.
"Wet products can lose 3% or more moisture to dehydration if not
frozen quickly enough," he noted. "Freezing as quickly as possible for
the selected baked item is important for retaining the desired moisture
within the product."
Meanwhile, freezing pizza poses several unique challenges. For starters, multiple ingredients require different freezing temperatures in
one package.
Fortunately, pizzas are relatively thin, making them a good candidate
for rapid freezing. "However, pizzas typically have a large, circular footprint," Mr. Johnson said. "This feature causes pizzas to occupy quite a lot
of belt space. So, a relatively quick freeze and lots of belt real estate leads
to wide and/or fast conveyor belts leading to large freezers. Freezing mechanically can mean very large spiral freezers. Freezing cryogenically
can decrease the equipment size by up to four times."
Loose toppings are another potential issue when air circulation
blows them off the product. Mr. Johnson recommended applying heat
to quickly melt some toppings and encourage the loose items to stay in
Top: Using conveyors in a freezer requires close attention to design to avoid ice buildup and ensure
proper support in cold temperatures.
AMF Bakery Systems

Bottom: Filled baked snacks must be frozen properly to ensure product quality and prevent freezer
burn or other defects.
Bryan Moberly Photography

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Baking & Snack - June 2020

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