To determine the parameters to successfully co-mill various blends of barley and wheat at the same time to improve milling performance with minimal mill changes. In addition, the flours generated will be characterized for analytical and nutritional properties.
Barley is an ancient grain that was a staple food in the diet for many centuries. Consumption of barley offers a number of health benefits including a reduction in the risk for many diseases such as cardiovascular disease, diabetes and certain types of cancer. It can also assist with weight maintenance and positively improve the microflora in the gut. The compounds in barley responsible for these health effects include dietary fibre, ?-glucan and various phytonutrients, antioxidants and vitamins. As a result of the relationship between consumption of barley ?-glucan and cholesterol reduction, Health Canada approved a health claim for barley in 2012 (Health Canada, 2012). Foods containing 1.0 g of barley ?-glucan per reference food amount are eligible to use this health claim. Similar health claims exist in the United States, United Kingdom, Sweden and The Netherlands. However, despite the health benefits of barley consumption and the ability to use health claims on food products, consumption of barley has decreased and this is especially true in North America.
Previous investigations using hulless barley (HB) were conducted at Cigi and included an examination of the milling, analytical and nutritional properties as well as the production of various end-use products using wholegrain HB flour. Working through partnerships with both domestic and international organizations including plant breeders, crop research institutions, seed companies, flour mills and food processing companies, formulations for 18 different food products were successfully developed. Towards the end of this project a preliminary co-milling of HB and wheat was completed with promising results. However, the project ended and further co-milling trials were unable to be completed.
The objective of the current project was to further explore the potential of co-milling of HB and wheat. HB varieties were selected as they do not require any pre-treatment prior to milling, such as dehulling that would be required if hulled barley was used, and they have higher ?-glucan content than hulled barley varieties. Our previous investigation determined that milling performance was improved if barley was co-milled with wheat for a number of reasons. Firstly, co-milling does not require changes to the mill flow diagram of a typical wheat flour mill which prevents costly downtime and inefficient use of resources, which would be required to make modifications to the mill. A second advantage of co-milling is that it prevents the mill screens from clogging. Since wheat endosperm particles are more granular and less sticky, they help the sticky barley endosperm particles move through the mill screens. The current project also investigated the co-milling of non-waxy and waxy HB. The co-milling of non-waxy and waxy HB also provided an opportunity to determine if ?-glucan levels could further be improved as waxy starch types of HB have increased ?-glucan content over non-waxy starch types.
The results generated from this project have shown that it is possible to successfully co-mill HB and wheat and produce flours with acceptable analytical and nutritional properties. Although milling extraction rates decreased as the level of HB in the blend increased, mill throughput was maintained and only limited milling adjustments were required. Based on examination of the data and our experience we believe the proportion of HB in the blend could be further increased with additional minor mill changes. Waxy and non-waxy HB were also successfully co-milled to produce flour with acceptable analytical and nutritional properties. However, the particle size of this flour was coarse and additional minor changes at the mill level would be required to reduce the particle size. We hope that these results may entice commercial wheat flour millers to consider co-milling barley with wheat which would thereby helping stimulate commercial capacity for food barley.