Scientists turn sunflower oil waste into a powerful bread upgrade

 As interest grows in healthier alternatives to traditional wheat-based foods, scientists are exploring new ingredients that can improve nutrition without sacrificing practicality. One promising option is partially defatted sunflower seed flour (SF), a material left behind after sunflower oil is produced. This underused by-product has shown strong potential for enriching bread with protein, fiber, and antioxidant compounds.

"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 & TechnologyTesting 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.

Source: ScienceDaily