Less salt, more protein: Researchers address dairy processing's
environmental, sustainability issues
Date:
September 2, 2021
Source:
University of Illinois at Urbana-Champaign, News Bureau
Summary:
Researchers say the high salt content of whey -- the watery part
of milk left behind after cheesemaking -- helps make it one of the
most polluting byproducts in the food processing industry. In a
new study, chemists demonstrate the first electrochemical redox
desalination process used in the food industry, removing and
recycling up to 99% of excess salt from whey while simultaneously
refining more than 98% of whey's valuable protein content.
FULL STORY ========================================================================== Researchers say the high salt content of whey -- the watery part of
milk left behind after cheesemaking -- helps make it one of the most
polluting byproducts in the food processing industry. In a new study,
chemists demonstrate the first electrochemical redox desalination
process used in the food industry, removing and recycling up to 99%
of excess salt from whey while simultaneously refining more than 98%
of whey's valuable protein content.
========================================================================== According to the U.S. Department of Agriculture, cheese consumption has
soared in recent years, and projections estimate its continued growth. The study reports that cheese production contributes to roughly 83% of the
total waste stream in the dairy industry. This environmental detriment,
along with a rapidly increasing population need for sustainable food
systems, inspired University of Illinois Urbana-Champaign chemical and biomolecular engineering professor Xiao Su to approach this challenge
using advanced electrochemical technologies.
The desalination process introduced in this study uses up to 73%
less energy and functions at 62% of the operating cost associated with conventional desalination systems, the researchers said. The findings
of the study led by Illinois graduate student Nayeong Kim are published
in the Chemical Engineering Journal.
"Although excess whey is wracked with several environmental waste
problems, the food industry also recognizes it as a valuable nutrient
source," Su said. "By demineralizing the highly concentrated salts in whey waste in a sustainable manner, we can eliminate one of the environmental hazards associated with dairy processing while simultaneously unlocking
access to the valuable protein resource found in whey waste." Su and his
team approached this challenge by introducing a chemical redox- coupled dialysis system -- a device that is not all that different from a battery
cell. The method comprises two independently controllable channels for
the whey waste and the electrodes, separated by a pair of ion-exchange membranes. Su said the process allows continuous desalination via a
reversible redox reaction.
"Our system recovers valuable whey proteins without the risk of protein aggregation or denaturation," Kim said. "Also, the molecular size of
redox species is larger than the membrane pore size, meaning it cannot
cross over the membrane to contaminate the purified proteins. I believe
that the redox- mediated electrodialysis system can revolutionize the
food industry by tackling coupled environmental and nutrition crises."
During the protein purification process, positively charged sodium
ions move from the feed to the redox channel and become chemically
reduced at the negative electrode. The negatively charged chloride
ions move to the redox channel when the reduced ions are oxidized at
the positive electrode, resulting in a sustainable regeneration of the
redox couple. The study reports that the redox channel can maintain
its electrolyte concentration by releasing the removed ions to the feed channel, and recovered sodium chloride can be reused to season cheese,
making it a net-zero waste process.
"Remarkably, the performance of protein purification and salt recovery
was maintained over multiple cycles, demonstrating outstanding stability
and cyclability," Su said. "Overall, our redox-electrochemical process
offers a sustainable and electrified platform for the recovery
of valuable proteins from dairy production waste, with envisioned
integration with renewable electricity in the future. We hope this will
be the start of research into sustainable food manufacturing in general." ========================================================================== Story Source: Materials provided by University_of_Illinois_at_Urbana-Champaign,_News_Bureau.
Original written by Lois Yoksoulian. Note: Content may be edited for
style and length.
========================================================================== Journal Reference:
1. Nayeong Kim, Jemin Jeon, Johannes Elbert, Choonsoo Kim, Xiao
Su. Redox-
mediated electrochemical desalination for waste valorization in
dairy production. Chemical Engineering Journal, 2022; 428: 131082
DOI: 10.1016/ j.cej.2021.131082 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2021/09/210902124935.htm
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