How pea flour processing affects product quality, improves nutrition levels in breakfast cereal: Cigi study

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Pea ingredients can improve nutritional levels of corn-based breakfast cereals and reduce glycemic response according to results of a study conducted by Cigi’s pulse area.

The research focused on how processing conditions of yellow peas can affect nutritional and end-product quality, says Heather Hill, Project Manager, Pulse Flour Milling and Food Applications.

“Consumers view many breakfast cereals as low in nutrition with starchy low-protein ingredients,” she says. “This study aimed to investigate the effect of adding yellow pea ingredients varying in particle size and composition on the nutritional levels of an extruded corn meal-based breakfast cereal.”

Yellow pea ingredients were combined with corn meal, pea fibre, sugar and salt and processed into a corn pop style breakfast cereal.

Yellow pea ingredients were combined with corn meal, pea fibre, sugar and salt then extruded into a corn pop style breakfast cereal.

Whole yellow peas were roller milled at Cigi into whole pea semolina, refined (de-hulled) pea semolina, whole pea flour and refined pea flour and their quality characteristics were evaluated for moisture, protein, total dietary fibre, total starch, starch damage and particle size distributions.

The four different pea ingredients were then each combined at a level of approximately 56.5% with corn meal (31.5%), pea fibre (6.5%), sugar (5%) and salt (0.5%) and processed into an extruded cereal product. A corn meal-based control sample containing fibre, sugar and salt was also produced. The samples were then compared for nutritional characteristics including protein, dietary fibre, and nutrients such as iron, potassium, folate, niacin and riboflavin content, as well as physical quality.

“We were focusing on nutritional quality, specifically on increasing levels of protein and fibre to achieve a nutrient content claim,” Heather says. “So we worked on developing a formulation to maximize the amount of pea ingredient that could be used while still getting a product with similar quality to a corn pop style breakfast cereal.”

She explains that 5 grams of protein per 30 gram serving qualifies for a protein claim in the U.S.  The research revealed that although higher levels of protein and fibre could be achieved, higher amounts of fibre compromised extruded cereal product quality with a greater density or heaviness for a corn pop style product than generally accepted by consumers.

 

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“The type of pea ingredient typically affected the physical quality of the cereals,” Heather says, noting that fibre was higher in cereals made with whole pea ingredients due to inclusion of the pea hull. “Pea flour-based cereals had more irregular surface texture compared to those made with pea semolina which also contained more protein. Therefore we recommended that semolina ingredients be used which, with a coarser granulation, are more manageable in extrusion processing as they produce less dust although particle size has to be limited to prevent any clogging.”

Overall results showed that pea ingredients significantly improved the nutritional composition of breakfast cereals, Heather says. Aside from whole pea semolina containing the most fibre, whole pea flour contained the most folate and iron, while refined pea semolina contained the highest nutrient content for protein, potassium, niacin and thiamine. Refined pea semolina also had the best physical qualities including a low density, higher number of air cells and extended bowl life making it the best overall choice as a pea ingredient in breakfast cereals.

These results were presented in a poster entitled The Effect of Pea Flour Processing on the Nutritional Quality and End-Product Quality of Extruded Breakfast Cereals at the AACC International annual meeting held last October in Savannah GA.

 Reducing glycemic response

For the project, analysis was later conducted on glycemic response.  In addition to a breakfast cereal advisory group representing Cigi, Pulse Canada, Canadian Grain Commission and food processors in Canada and the U.S., the Cigi pulse area worked with an international pulse task force committee. This international group was composed of members from Buhler, Pulse Canada, grower groups and food processors who were interested in the effects of extrusion processing on glycemic response and to what degree it can be reduced.

Testing conducted at Agriculture and Agri-Food Canada for the project indicated that breakfast cereals made with 100% pea ingredients, and blends containing pea ingredients both reduced glycemic response. Differences between them show that glycemic response can be influenced by formulation and changes in extrusion processing.

“Processing conditions can affect both end-product and nutritional quality, particularly affecting glycemic response,” Heather says, adding that over- and under-processing each have different impacts on the quality characteristics of the cereals.

She says that the results also suggest that one nutritional target should be selected (protein or fibre or reduction of glycemic response) in processing to balance improvements in nutrition with a product quality that appeals to consumers.