Influence of ultrafine grinding treatment on the physicochemical and antioxidant properties of Chinese ginger (Zingiber officinale Roscoe) dietary fibre

Chinese ginger (Zingiber officinale Roscoe) DF powder was obtained by regular grinding and then by ultrafine grinding, whose effects were investigated on the composition, functional and antioxidant properties of Chinese ginger DF products. The results indicated that ultrafine grinding could effectively pulverize the fibre particles to micro-scale. With particle size decrease, the water holding capacity (WHC) and oil binding capacity (OBC) of Chinese ginger DF were significantly (p< 0.05) decreased and the water retention (WRC) capacity, swelling capacity and nitrite ion absorption capacity were increased. The antioxidant activities of ginger and DF before and after grinding were in terms of ABTS radical scavenging activity, DPPH radical scavenging activity, ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC) and total phenolic content (TPC). Micronized insoluble DF showed increased ORAC and TPC yet decreased ABTS radical scavenging activity. DPPH and FRAP had no significant change in this paper. One kind of health beneficial DF was obtained with higher soluble DF content, WRC, swelling capacity, nitrite ion absorption capacity and antioxidant activity (ORAC, FRAP and TPC) by ultrafine grinding. This study could be useful for the application of ultrafine grinding technology in food industry.