Our current fascination with high-protein foods means plant-based protein now shows up in many food products. But rather than growing plants just for their protein, researchers wondered if edible flowers — like pot marigolds that are usually composted or thrown away once they’re past their prime — could be a new, sustainable plant-based protein source. So, they measured the protein content and composition of dried marigolds, and they report the results in ACS Food Science & Technology .
“Marigold flowers are widely cultivated, yet an estimated 40% of production is discarded as waste, especially after ornamental use,” says Anand Mohan, the corresponding author of the study. “We saw an opportunity to valorize this agricultural byproduct by exploring its protein fraction, given the growing demand for plant-based and sustainable food ingredients.”
The researchers ground pot marigold flowers (Calendula officinalis) into a fine powder and isolated proteins in four sequential liquid extractions, collecting different protein molecules into each mixture. Their lab tests showed that:
Some protein extracts contained high levels of glutamic acid and aspartic acid, which could add umami taste to foods.
Marigold proteins stayed stable up to 221 degrees Fahrenheit (105 degrees Celsius), which is hotter than temperatures tolerated by other plant proteins like pea and chickpea, suggesting the flower’s proteins would keep their structure better in heated foods.
Two protein extracts had excellent emulsifying capacity, or the ability to keep oil droplets distributed in water, suggesting their suitability for salad dressings, mayonnaise and dairy substitutes.
This research shows that marigold flower proteins could be a new source of food protein and are suitable ingredients for further use in food product development. The marigold protein’s emulsifying, hydrating and antioxidant effects found in this paper, says Mohan, make it ideal for nutrient-enriched food formulations. They could improve the taste, stability, and texture of bakery products and emulsion-based foods.
The researchers next plan to study the health benefits of marigold protein and then use it as an ingredient in baked goods and products like salad dressings, which they’ll taste-test with consumers.
“People are increasingly aware of food waste and are seeking innovative solutions,” concludes Mohan. “Demonstrating that something as common and overlooked as a flower can be transformed into a valuable food ingredient makes science both relatable and impactful.”
The authors acknowledge funding from the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division for supporting the protein amino acid identification component of this research.
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ACS Food Science & Technology
10.1021/acsfoodscitech.5c01215
Marigold flowers show potential as a source of plant-based protein
29-Apr-2026