Effect of jet milling on the physicochemical properties, pasting properties, and in vitro starch digestibility of germinated brown rice flour.

Germinated brown rice (GBR) flours were prepared by hammer milling and jet milling. The effect of the milling on the physicochemical and pasting properties of the resultant flours were investigated. The jet milling of GBR resulted in flour with different particle sizes, which were air-classified into coarse and fine size fractions. As the particle size decreased, the amount of damaged starch increased. The WAI, WSI, and oil absorption of the jet-milled GBR flour was slightly lower than that of the hammer-milled flour. Increased α- and β-amylase activities were observed in the coarse fraction of the jet-milled GBR flour compared with the hammer-milled and jet-milled fine fractions. The RVA viscosity profiles of the fine fraction of the jet-milled GBR flour were significantly higher than those of the hammer-milled or the coarse fraction of the jet-milled GBR flour. Compared with the hammer-milled flour, jet milling increased in vitro starch hydrolysis.