Using synchrotron light to determine optimal particle size for milling

Chickpeas, lentils, beans and peas are a fast-growing food market, with new uses going well beyond bean salads and hummus—think brownies, vegan meats, and salad dressing. Researchers like Chitra Sivakumar are working to drive dining innovation by studying the tiniest details of flours made from these pulses. Sivakumar has three publications in the journal Advanced Powder Technology.

“This is what I want to create, what the research is about: a specific flour for a specific product,” says Sivakumar, who conducted her doctoral research on pulse flours under the supervision of Dr. Jitendra Paliwal at the Grain Storage Research Lab at the University of Manitoba.

The study explored how particle size, protein and starch, and other micro-properties of milled pulse flour influence the quality of the end product. Processing rice and wheat flours is standardized because century-old research on these crops has helped establish and optimize particle size for milling; however, pulse flours have not received the same attention.

Sivakumar explains that consumers and food producers are interested in pulse-based food products because beans and lentils are great sources of fiber and protein. They’re also good for the environment: Pulse Canada estimates that growing 10 million acres of pulses can capture 4.1 million tons of CO₂ emissions per year—the output of approximately 1.2 million passenger vehicles.

“Many consumers want to switch to the pulse-based proteins rather than animal-based proteins. But when they are looking in the grocery store they do not have many options,” says Sivakumar. She is using the Canadian Light Source (CLS) at the University of Saskatchewan to conduct specialized research aimed at changing that.

Sivakumar and her colleagues studied more than 60 flours from four pulse crops to understand how milling affects them. The ultrabright synchrotron light enabled them to see how starch and proteins were mixed together, the extent to which they were damaged by milling, as well as texture, getting a molecular-level picture of the size and distribution of the milled particles—not just at the surface, but within the flour.

“All these results can be applied on both the agricultural producer side and in pulse milling processes,” says Sivakumar. Her research into starch and protein can inform decisions on what varieties to plant for different purposes, while the insights into particle size can help refine milling techniques.

“I am so glad we were able to use this wonderful facility for our research. The resolution and accuracy level is so good—I would say it is really brilliant.”