PET Food Processing - June 2020 - 28

"Research shows each antioxidant benefits the immune
system uniquely, so one antioxidant at high levels is not as
effective as a group of antioxidants acting together."
Eric Altom, Balchem Corp.
and acids that exert additional, and typically more putrid flavors and odors.
"An oxidized pet food will be perceived by pet owners as a sign of poor quality, or even a danger to their
animal's health," Caseria said. "And actually, they are
not completely wrong. The altered chemical structure of
lipids makes them less bioavailable for the animals. So
even though oxidation won't harm a pet, it can certainly
damage the food's nutritional value.
"Limiting oxidation is crucial to preserve the shelf stability and nutritional quality of a pet food," Caseria said.

Adding antioxidants

Ingredients'
antioxidant
properties are
commonly called out
as health benefits of
the product on pet
food packaging.
Mars Petcare

The most common approach to inhibit lipid auto-oxidation is to include antioxidants in the formulation. This
is often done throughout the supply chain, particularly
with kibble manufacturing.
"Choosing the right place and the right moment for
their addition is crucial," Caseria said. "Antioxidants
should be added as early as possible, as well as regularly
throughout the manufacturing process."
The fight against oxidation commonly starts at the
renderer's plant, where antioxidants are added in with
the raw materials used to produce the fats, oils and
meals that will go into the kibble.
"Additional antioxidants may also be added directly to the final meals and oils by the renderer prior to
packaging," Caseria
said. "The fight then
continues to the pet
food manufacturer's
plant. When meals
and oils are stored
for a long period before being processed,
or if they have not
been stabilized at
the renderer's facility,
pet food manufacturers may add antioxidants to protect them
during extrusion."
For extra protection
with kibble and dried
snacks, antioxidants
may be sprayed on sealing each piece to ensure lipid preservation
throughout the product's shelf life.

Traditional synthetic antioxidants are very effective,
easy to use and low cost. However, being chemically
derived, they are undesirable in today's clean label environment. In response, formulators are embracing
clean label antioxidants, with the most common options
classified as tocopherols (vitamin E) and high-phenolic
plant extracts.
"Chemical antioxidants are liabilities in the clean label
movement," said Robert Ames, senior business development manager, Corbion, Lenexa, Kan., which markets
natural antioxidants.
Kerry Courchaine, director of technical services,
Darling Ingredients, Irving, Texas, said, "Where natural
antioxidants were once only requested by premium and
super-premium pet food brands, we now receive natural
requests from mid-market pet food brands."
Mixed tocopherols and botanical extracts are added
to many of Darling Ingredients' rendered products for
pet food formulating.
"At times, a rendering plant may choose to use a natural chelator, such as citric acid or ascorbic acid, to bind
free-radicals when rendering challenging raw materials
with the potential for high ash content, which might
otherwise promote oxidation during the rendering
process," Courchaine said. "Our facilities use a variety
of natural antioxidant formulas, whether specified by a
customer, or necessary due to some unique challenges of
the rendered products."
The technical team constantly monitors each pet food
ingredient facility to determine the best natural option
available to prevent oxidation. In recent years, a poultry
industry trend has been to move toward all-vegetarian
diets for their birds.
"These diets translate to higher levels of unsaturated
and polyunsaturated fatty acids, which are more prone
to oxidation," Courchaine said. "The move away from
rendered by-product meals toward more label-friendly
rendered proteins, such as chicken meal and turkey
meal, exacerbates the oxidation problem. These meat
meals tend to be higher in ash, a source of oxidizing free
radicals, such as copper and iron.
"Chicken meal and turkey meal are also the products of
such raw materials as edible necks, backs, frames, skins,
and bone residue from deboning operations," she said.
"These raw parts harbor strong oxidizing agents, such as
chlorine and peracetic acid, used in carcass rinses."
Altom added, "To ensure proper shelf life and longterm stability, it is critical to control the oxidativereduction reactions. One way to support this foundation
is to provide organic trace minerals. These are minerals

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