Effects of heat treatments on the safety and nutritional properties of whole grain barley
Health claims for barley β-glucan (BG) have prompted the development of more food products using barley. Some new products do not use any form of heat treatment which could become an issue as barley has been found to have high microbial contamination. The aim of this research was to evaluate current commercial barley products for microbial and BG quality and determine the effects of different heat treatments on the safety and physicochemical properties of BG of whole grain barley. Three heat treatments (micronization, roasting and conditioning) were performed on 3 cultivars of barley (CDC Rattan, CDC McGwire and CDC Fibar). The microbial quality was measured with standard plate count (SPC), yeast and mould (MYC), and coliforms/E. coli. Only 4 of the 17 commercial barley products tested met acceptable microbial limits used in this study. All 3 heat treatments reduced SPC, MYC and coliforms to acceptable levels. BG was extracted using an in vitro digestion method to determine its viscosity, molecular weight (MW) and solubility. Heat-treated barley increased the BG viscosity and MW compared to the untreated barley. The effect of heat treatment on starch pasting, particle size and colour were also evaluated. Overall, heat treatments improved the safety and potential health benefits of whole grain barley.