Effects of heat-moisture treatment on normal and waxy rice flours and production of thermoplastic flour materials.

Different levels of heat-moisture treatment (HMT) were applied to normal and waxy rice flours. Changes in chemical composition and functional properties of both flours were investigated. It was found that HMT induced β-turn conformation of rice proteins. Levels of HMT and types of rice flour interactively influenced thermal properties and XRD patterns of flour. When heat-moisture treated flour was utilized for production of thermoplastic flour (TPF) materials, it was found that HMT improved continuity of injection molding, complete mold filling, and yielded homogenous TPF materials. HMT levels affected the mechanical, thermal and barrier properties of TPF resin and materials differently. The ratio of HMT level to native flours was proposed for use not only for resin processing and injection molding, but also for improving mechanical and barrier properties of TPF materials.