Cigi has been investigating better ways to mill Canadian food (hulless) barley into flour which may increase its potential for commercial use as a healthy ingredient.
Preliminary work done several years ago revealed that milling performance of food barley is improved when it is blended with wheat, producing flour with enhanced nutritional properties. It was found that including 15% barley with wheat had no adverse effect on the milling process.
Further evaluations were recently completed in a year-long project intended to determine the specific blends that would provide optimum milling performance and nutritional quality in the flour. The results showed that up to 40% hulless food barley can be milled with wheat to produce a quality flour with suitable levels of beta-glucan, an important nutritional component. The work will help Cigi develop guidelines for the milling of hulless food barley for the milling industry.
Funded by Alberta Innovates Bio Solutions and Alberta Barley Commission (ABC) with food barley varieties also supplied by ABC, the project was carried out by Cigi’s milling and analytical services areas. Work focused on developing milling techniques and other information that would improve the competitiveness of flour produced from Canadian food barley and wheat in health food and ingredient markets.
Food barley has a number of beneficial health properties – consumption can reduce the risk of coronary heart disease, regulate blood glucose levels, and possibly offset certain cancers. The benefits are attributed to beta-glucan, phytonutrients, antioxidants, and vitamins contained in barley. In addition, Health Canada approved a health claim in 2012 for foods containing 1.0 gram of barley beta-glucan per serving as a way to lower cholesterol.
The project builds on the previous research Cigi conducted in 2008-09 in which new opportunities for foods made with barley were identified and developed in partnership with international and domestic companies. During that time a commercial bakery asked Cigi to try blending 15% barley with wheat to mill flour for pan bread, says Ashok Sarkar, Senior Advisor in Cigi Technology and the project leader.
“The initial co-milling of barley and wheat was successful but not pursued further at the time,” he says. “We found that including 15% barley with wheat had no adverse effect on the milling process but at that level there was also no real increase in the level of beta-glucan which is what people are interested in from a nutritional standpoint.”
Hulless barley is easier to work with since there isn’t a requirement to remove the hulls prior to milling, says Elaine Sopiwnyk, Cigi Director of Grain Quality. However, hulless food barley varieties, especially those that are characterized as “waxy,” are also sticky when milling (waxy starch properties are associated with higher levels of beta-glucan as well as lower levels of amylose, a component of the starch, which contributes to the stickiness). Although this stickiness can pose a problem for millers, blending the barley with wheat appears to help resolve the issue.
Wheat is coarser and more granular which helps with sifting and prevents the barley flour from clogging the sifter screen perforations during the milling process, Ashok says. The current project used hulless barley with three different starch characteristics – normal, partial waxy, and fully waxy starch – blended with wheat at 20%, 30%, and 40%. Throughput, or milling capacity, was maintained at the same rate for all millings.
Commercial millers aim to manage throughput and extraction levels to meet a required particle size to control their costs, Ashok explains. “For the current project we never changed the throughput on the mill, which is an important aspect; however, we did see some drop in (flour) extraction rate from what we would get if we just milled wheat.”
Elaine concurs that a slight drop in extraction when co-milling barley is only a minor drawback for millers. “I think the project showed that millers can do this – there’s no tempering required of the barley so it can be used whenever they need it, and they don’t have to change their screens or throughput to make a flour that has improved nutritional quality over flour made from 100% wheat.”
In 2005 Ashok successfully milled the first registered non-waxy hulless food barley variety in Canada, Millhouse, at a relatively high extraction rate of about 74.6%. “I said then we could actually someday take barley from one bin and wheat from another and mill them together. But that was just a hypothesis, then this request from a bakery customer happened so we tried it.”
The current project came about when Cigi’s milling results were presented at a meeting of barley researchers at the Richardson Centre for Functional Foods and Nutraceuticals, he says. ABC was in attendance and recommended that Cigi apply for funding for further work.
“ABC supported the project from the start and provided three hulless food barley samples for us to work with – CDC McGwire (normal starch or non-waxy), CDC Rattan (partial waxy), and CDC Fibar (full waxy),” says Elaine, adding that milling a blend of the waxy and normal starch barley to achieve higher levels of beta-glucan was also investigated.
The project showed that although up to 40% hulless food barley can be milled with wheat to produce a quality flour, the proportion can be successfully increased up to 50% with some minor adjustments made to the mill screens.
Ashok points out an increase in the amount of barley used in the blend with wheat also results in increased water absorption in the flour which has to be managed for baking pan bread. “When beta-glucan content is high it tends to take up a lot more water which can cause problems in the bread baking processes. This is an area for further investigation.”
Baking trials using flours produced from the co-milling of CDC Rattan and Canada Western Red Spring (CWRS) required only small changes in processing and formulation and overall were found to result in pan breads with acceptable handling properties and end-product quality.
Elaine says that the inclusion of 40% hulless barley produces enough beta-glucan to meet the US health claim of 0.75 grams of soluble beta-glucan per serving but proved to be more difficult to reach the 1.0 gram per serving required for a health claim in Canada.
“Our attempt to increase beta-glucan levels to meet the Canadian health claim in pan breads were unsuccessful but we plan to further examine the potential of additional blends in order to produce a flour that has the required functionality and beta-glucan levels,” she says. “We hope to continue working with the material generated in this project to further develop our knowledge so that we can continue promoting the use of food barley.”
Elaine adds that connections within the industry have allowed Cigi to collaborate with other organizations to more fully examine the material generated from the project. “Not only has this work added to our knowledge about food barley but it has also benefitted those we have collaborated with.“