Recent studies reveal that orange peel extracts may help combat cardiovascular disease, offering a new use for this often-wasted citrus byproduct.

According to the American Heart Association, of Hispanic adults over 20 in the United States from 2015 to 2018, 52.3% of men and 42.7% of women had cardiovascular disease, a condition that caused 31,864 deaths among men and 26,820 among women of all ages.

Research has shown that some intestinal bacteria help in the development of cardiovascular disease. When they feed on certain nutrients during digestion, these bacteria produce Trimethylamine N-oxide (TMAO). According to researchers at the Cleveland Clinic, TMAO levels may help predict future cardiovascular disease.

With the help of the U.S. Department of Agriculture, University of Florida's UF/IFAS Citrus Research and Education Center professor Yu Wang and her research team studied the potential of orange peel extracts, rich in beneficial phytochemicals, to reduce TMAO and trimethylamine (TMA) production. The scientists experimented with two types of extracts: a polar fraction and an apolar fraction.

To obtain the different polarity fractions, the scientists used polar and nonpolar solvents in the orange peels.

“Imagine your salad dressing, whatever is in the water or vinegar part is the polar fraction; whatever is in the oil away from the water is the non-polar fraction,” Wang said in remarks reported by the University of Florida.

“The solvents we used were not exactly like water and oil, but they have similar polarity,” she added.

According to the university, study results showed that extract of the non-polar fraction of orange peel effectively inhibits the production of harmful chemicals. The researchers also identified a compound called feruloyl putrescine in the extract of the polar fraction of orange peel, which also significantly inhibits the enzyme responsible for the production of TMA.

“This is a novel finding that highlights the potential of feruloyl putrescine in health by reducing the risk of cardiovascular disease,” Wang said.

The finding in orange peel is significant because 5 million tons of peels are produced each year during juice production in the United States. Nearly 95% of Florida oranges are used to make juice, with half of the peels going to livestock feed, and the rest going to waste.

The U.S. Food and Drug Administration considers the natural extracts in orange peel to be safe for human consumption. Therefore, Wang hopes to put them to better use.

“The findings suggest that orange peels, often turned into waste in the citrus industry, can be reused as valuable health-promoting ingredients, dietary supplements, or food ingredients. Our research paves the way for the development of functional foods enriched with these bioactive compounds, providing new therapeutic strategies for heart health,” Wang said.