The use of thermal treatments to reduce any off-flavours in pulses processed as ingredients in commercial food products may soon become the way of the future.
A one-year project recently completed at Cigi confirmed through quality and sensory analysis that infra-red heating, or micronization, and roasting improved the flavour of pulses used as ingredients in baked foods, says Peter Frohlich, Project Manager, Pulses and Special Crops.
Peter explains food manufacturers prefer little or no flavour in pulses when adding them as ingredients to improve nutritional levels in their processed food products. The ability to diminish pulse flavour in turn can increase demand for pulses as ingredients.
“I think thermal processes will be used in future as a way to treat pulses before they become ingredients,” he says. “Food companies generally seek out ingredients with less flavour to increase nutrition so it’s important we have been doing the research to determine how thermally treated pulse ingredients affect the quality of baked food products.”
Funded by Manitoba Pulse and Soybean Growers (MPSG), Peter says the first part of the project focused on sourcing Manitoba-grown seed, resulting in the selection of yellow peas, navy beans and faba beans. The second part involved pre-treating the pulses through roasting at Cigi and micronization at Infraready Products Ltd. in Saskatoon. The pulses were then milled into flour on Cigi’s Ferkar mill, purchased last year with support from the Manitoba government’s Grain Innovation Hub.
Micronization involves rapid heating of the pulses through electromagnetic heat while roasting uses dry heat through convective heat transfer. Both processes can add value to grains by causing physiochemical changes that can improve functional and nutritional properties including reduction of any undesirable flavours.
The most recent part of the project involved using the treated pulses as flours in pan breads, tortillas and pita breads, comparing untreated, micronized and roasted yellow peas, navy beans and faba beans. The pulse flours were incorporated at 15% in the pan breads and 30% in tortillas and pitas.
Peter notes that faba beans, which are high in protein and light in flavour, have not been widely grown in Manitoba possibly because the larger seed size has made it difficult to harvest with the same equipment used for smaller market classes more prevalently grown such as yellow peas. However, newer faba bean varieties with smaller seeds have been developed and production has increased.
“We expected peas to taste stronger and navy beans to have a different taste than the peas, but we didn’t quite know what to expect from faba beans,” he says. “Faba beans exhibited a lot less pulse or beany flavour which is a characteristic desired by the processed food industry.
“In Manitoba and other provinces organizations are setting up operations, trying to mill fababeans and get them into food products. This research is really timely and we feel the information will be valuable to MPSG.”
Results of the investigation were presented in a research poster at the AACCI annual meeting held last October in Savannah GA. Overall, conclusions indicate that thermally treated pulses can be successfully incorporated as ingredients in food formulations as they show improved flavour and have small to moderate effects on product quality, depending on the product processed and type of pulse used. For example, dimensions of yellow pea tortillas and navy bean pita breads were affected in a minor way while the volume of pan breads was unaffected by thermal treatments of the pulse ingredients.
Subsequent consumer assessment of sensory characteristics of the baked products indicated that micronized and roasted treatments had the greatest impact on pan breads with the consumer panelists showing increased favourability and intent to purchase for all three pulse classes. Less impact and consistency was reported with tortillas and pitas although the treatments helped decrease beany flavour or bitterness and increased consumer preference and intent to purchase.
“This study just reinforces that in order to get pulses into the market at a high rate industry should address the flavour of these commodities,” Peter says.
The quantitative data supports Cigi’s initial hypotheses that thermal treatments can improve on the flavour of pulse ingredients, which also opens the door to further work, he says. “There are many additional questions such as the cost of processing which is an important consideration as well as finding out how to adjust the treatment parameters to develop optimized pulse ingredients.”