Citrus peel has long been viewed as a byproduct of juice processing, often ending up as animal feed or compost. New research suggests it may deserve much more attention. Scientists found that pectin extracted from citrus peel has excellent functional properties that could increase its value for use in food, beverage and pharmaceutical products.
The study was published in the journal Polysaccharides. It was conducted by Leila Mohammadi, Gholamreza Kavoosi and Fatemeh-Sadat Hashemirad of Shiraz University in Iran and Seyed Mohammad Mahdi Dadfar of the Institute of Nanoscale and Biobased Materials in Germany.
Researchers extracted pectin from the peels of seven citrus species: sweet orange, bitter orange, lemon, lime, grapefruit, pomelo and mandarin. They evaluated each pectin for its chemical makeup, thickening ability, water-holding capacity, antioxidant activity and other characteristics important to commercial uses.
The researchers found that all seven citrus species produced high-quality pectin. Lemon, grapefruit, sweet orange and mandarin peels contained pectin levels comparable to commercial pectin products. The pectins also demonstrated excellent water-holding capacity, swelling ability and viscosity, making them well suited for use as natural thickeners, stabilizers and gelling agents in processed foods.
Another key finding was that each citrus species produced pectin with slightly different properties. For example, pomelo pectin showed particularly strong viscosity and stability, while lemon and grapefruit pectin exhibited somewhat greater antioxidant activity. These differences could allow processors to match specific citrus varieties with particular end uses.
For citrus growers, the research highlights another way the industry can add value beyond fresh fruit and juice production. If processors can develop additional markets for citrus pectin, peel could become a more valuable raw material rather than simply a processing byproduct. That could improve the overall economics of citrus production while supporting more sustainable use of harvested fruit.
The researchers concluded that citrus peel pectin has significant commercial potential because of its favorable processing characteristics and bioactive properties. They note that additional research could further improve pectin’s functionality and expand its use in foods, dietary supplements and pharmaceutical products.
See the full study: Multifunctional Citrus Peel Pectins From Seven Species: A Comparative Study of Physicochemical, Techno-Functional and Bioactive Properties.
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