Scientists discover this common garden flower could be a powerful protein source

Scientists are now focusing on agricultural byproducts to address the global need for sustainable nutrition. An innovative study featured in ACS Publications reveals that pot marigold (Calendula officinalis) can serve as a robust and thermally stable protein source. Although people usually grow these plants for decoration and medicinal use, researchers found that marigold petals contain protein isolates with superior thermal stability to traditional sources such as peas and chickpeas. This finding stands out for the food industry because around 40 per cent of marigold biomass is currently discarded as an agricultural byproduct. By making use of this floral residual biomass, the industry has an opportunity to develop robust plant-based emulsions and high-protein additives while supporting a circular bio-economy and reducing environmental impact. Transforming these neglected petals into nutritional powerhouses effectively bridges the gap between environmental sustainability and innovation.The core of this discovery lies in the structural resilience of the marigold protein. The American Chemical Society (ACS) shared research showing that proteins from Calendula officinalis withstand higher temperatures before denaturing compared to many commercial plant proteins. This characteristic means the protein retains its functional integrity when exposed to high heat during processes like pasteurisation or baking. As a result, it’s an ideal candidate for creating plant-based products that need a longer shelf life.Research from the study shows that marigold protein isolates have outstanding emulsifying properties. These proteins are rich in essential amino acids and flavour precursors like glutamic and aspartic acids, which are responsible for the ‘umami’ taste as noted in research published in ACS Publications. Because of this unique chemical composition, these proteins can boost nutrition and naturally enhance flavours in savoury foods. Furthermore, the United Nations Food and Agriculture Organisation (FAO) stresses the importance of ‘valorisation,’ which involves transforming waste into valuable resources to secure future food supplies. Marigolds, already grown worldwide for their essential oils, offer another opportunity: using petals left over after oil extraction to produce protein creates supplementary revenue streams for producers while also mitigating carbon emissions associated with plant-based protein production. Research shows marigold protein creates more stable oil-in-water emulsions compared to soy and whey proteins. The USDA emphasises the importance of finding alternative proteins that don't compete with key food crops like soy. This is crucial for maintaining biodiversity and ensuring the food supply chain remains resilient against climate-related crop failures.