Scientists turn sunflower oil waste into a powerful bread upgrade

“Our aim was to optimize the reuse of sunflower seed flour considering its high protein and chlorogenic acid content,” says biologist Leonardo Mendes de Souza Mesquita, who is currently based at the Institute of Biosciences of the University of São Paulo (IB-USP) in Brazil. He is the lead author of a study published in ACS Food Science & Technology.

Testing Sunflower Flour in Bread Recipes

To evaluate how sunflower seed flour performs in baking, the research team prepared bread recipes that replaced wheat flour (WF) with sunflower seed flour (SF) at levels ranging from 10% to 60%. Each version was carefully analyzed for its chemical makeup, dough behavior, and the physical characteristics of the finished bread.

“Sunflower seed flour has been shown to contain a very high percentage of protein, from 40% to 66%, as well as dietary fiber, iron, calcium, and high levels of chlorogenic acid, a phenolic compound associated with antioxidant, anti-inflammatory, and hypoglycemic effects,” Mesquita explains. He adds that using this by-product increases the nutritional value of bread while lowering the environmental footprint of sunflower oil production. Because it is sold cheaply to avoid disposal, sunflower seed flour is also a low-cost ingredient.

Major Gains in Protein and Antioxidants

The results showed clear nutritional improvements. Breads made with sunflower seed flour contained significantly more protein and fiber than standard wheat bread. At the highest substitution level, the bread reached 27.16% protein, compared with 8.27% in conventional bread. Antioxidant levels rose alongside protein content.

Antioxidant activity was measured using Trolox, a water-soluble analog of vitamin E that serves as a reference standard. The values recorded in sunflower flour breads were much higher than those seen in bread made entirely from wheat flour.

“The result reinforces the potential of sunflower seed flour to promote health benefits associated with reducing oxidative stress,” says Mesquita. He also notes strong inhibition of digestive enzymes, including α-amylase (92.81%) and pancreatic lipase (25.6%), suggesting that bread containing SF or SFE may help slow the digestion of starches and fats.

Clean Processing and Food Safety

Another key finding involves how sunflower oil is produced. According to the researchers, industrial extraction relies on mechanical pressing rather than chemical solvents. As a result, the leftover flour is free from processing contaminants, aside from residues already present from agricultural sunflower cultivation.

While the nutritional benefits were clear, higher amounts of sunflower seed flour affected how the bread looked and felt. When SF made up 20% or more of the recipe, loaves became smaller and firmer. Changes in crumb structure also led to denser bread with reduced softness.

“However, adding the aqueous extract [SFE] managed to preserve the structure and texture of the breads, keeping them close to those of traditional wheat bread,” Mesquita says. He explains that this approach allows bakers to gain the nutritional advantages of sunflower flour while minimizing negative effects on texture.

Using Sunflower Extract to Improve Bread Quality

The aqueous extract is produced by mixing sunflower seed flour with water and filtering it, without requiring additional physical or chemical treatments. Mesquita suggests that future work could explore whether SFE might fully replace SF or be blended with it in different ratios. Commercial bakeries could then determine which formulations work best at scale.

Sustainable Innovation and the Circular Economy

This research is part of a larger effort to find productive uses for industrial leftovers. “Transforming waste into products is a fundamental strategy for promoting a circular economy and reducing resource waste,” says Mesquita. He notes that partially defatted sunflower seed flour supports human health while also delivering environmental and economic benefits, addressing all three pillars of the circular economy.

The circular economy seeks to move away from the traditional “extract, produce, discard” approach. Instead, it aims to keep materials in circulation longer, maximize their value, and regenerate resources at the end of each cycle. In this case, an overlooked by-product has been turned into a functional ingredient that enhances bread nutrition while reducing waste.

Research Collaboration and Funding

The study involved scientists from the Multidisciplinary Laboratory of Food and Health (LabMAS) at the School of Applied Sciences of the State University of Campinas (FCA-UNICAMP) in Limeira and the Laboratory of Food Technology and Nutrition at the Federal University of São Paulo (UNIFESP) on its Baixada Santista campus. Funding was provided by FAPESP through six projects (13/04304-4, 20/15774-5, 18/14582-5, 20/08421-9, 15/00658-1, and 19/13496-0). Mesquita later received a Young Researcher Grant for the project “Sustainable Innovations: The Biorefinery Revolution through the Valorization of Macroalgae Using Renewable Solvents Toward a (Green/Blue) Economy.”