March 2022 - 24

OSU work turns apple waste into packaging material
By Sean Nealon
Oregon State University
A new study by Oregon State
University scientists outlines a key
advance in turning apple waste into an
environmentally friendly packaging
material that could serve as an
alternative to plastic.
Recycled newspaper has traditionally
been the main ingredient of so-called
molded pulp packaging products,
which have become increasingly
popular because they are compostable.
But the supply of recycled newspaper
is in decline, creating a market for
substitute materials.
Yanyun Zhao, an Oregon State
Yanyun Zhao, an Oregon State professor, conducts research that turns apple pomace into
an environmentally friendly packaging material that could serve as an alternative to plastic.
Photos: Oregon State University
professor who leads a research team
focusing on sustainable food packaging
and processing, has studied apple
pomace and other byproducts from
processing fruit and vegetable juice
and winemaking as an alternative for
recycled newspaper in molded pulp
manufacturing. She and the team
received a patent for this research.
" Right now, apple pomace is
typically just composted or used
for animal feed, " said Zhao, whose
research aims to reduce food loss and
waste across the food supply chain.
" We thought why not turn it into an
environmentally friendly product that
meets an industry need. "
Lignin is a polymer that forms key
structural materials in the support
tissues of most plants. Rhubarb
pomace, which is particularly lignin
rich, was used in this study.
Chitosan is a bio-based polymer
commonly used in the papermaking
industry. A previous study from Zhao's
team found that chitosan reduced
water absorption of cellulose nanofiber
(CNF) films significantly through
adsorption of chitosan onto CNF fibers
via hydrogen bonds.
Finally, glycerol is an organic
compound often added to a material
to make it softer and more flexible.
Previous studies had shown that at
low levels glycerol decreased water
absorption.
The researchers determined the
optimal amounts of those polymers
and compounds while also adding a
small amount of cardboard fiber for
stability of the molded pulp packaging
products.
Zhao's team has a long history of
Zhao envisions apple pomace being
the main ingredient for molded pulp
packing products such as take-out
containers, flower pots, beverage cartons
and bottles and clamshell packaging
used for fruits and vegetables.
She is focused on apple pomace, in
part, because it is readily available in
the Pacific Northwest. When apples
are processed for juice about 70-75%
of the apple goes into the juice, leaving
the remaining 25-30% as pomace.
One of the key problems to solve
in creating pomace and paperbased
packaging is improving water
resistance so that it could withstand
high moisture, liquid food or non-food
items and products stored under high
humidity conditions.
In a just-published paper in Food
and Bioproducts Processing, the
team sought to create eco-friendly,
bio-based, compostable and costeffective
solutions that would improve
the hydrophobicity, or water resistance,
of the apple pomace-based molded
pulp products.
24 | FruitGrowersNews.com
studying food coatings as a barrier
to water and gases. The team had
previously created a two-step
preparation of superhydrophobic
coating that is heat, cold and water
resistant. They applied a simplified,
one-step coating on the surface of
the apple pomace-based product to
enhance water resistance.
They concluded that the study
demonstrated the feasibility of using
fruit pomace as a new source of fiber
in producing molded pulp packaging
and effective approaches to enhancing
water resistance in those packaging
materials.
Co-authors of the paper are Clara
Lang, Jooyeoun Jung and Taoran
Wang, all of whom are former or
current members of the Sustainable
Food Packaging and Processing team
in the Department of Food Science and
Technology in Oregon State's College
of Agricultural Sciences.
The research was supported by the
Oregon Department of Agriculture
Specialty Crop Block Grant Program.
Kerr Concentrates Inc. of Salem
and Hood River Juice Co. of Hood
River provided fruit pomace for the
research. FGN
They used two strategies:
incorporating polymers and
compounds with characteristics
to improve water resistance into
the pulp formulation and applying
superhydrophobic coatings on the
product surface. The polymers and
compounds studied include lignin,
chitosan and glycerol.

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March 2022

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