2015 Volume 62 Issue 2 Pages 73-80
In this study, we extracted sago starch from sago pith waste (SPW) using a micro powder mill. The objectives were to recover the starch from the SPW and to understand the effects of micro powder milling on the physicochemical properties of micro-powder-milled sago starch. Milling was performed at different levels of disc clearance. Native sago starch extracted from sago pith, called untreated sago starch, was used as a comparison. The results show that micro powder milling of SPW can increase the sago starch yield by around 10‒17%, depending on the milling disc clearance. The amount of soluble starch in the SPW after micro powder milling was low for all treatments. The sago starch size distribution was wider at narrow clearance, but similar at wide, wide-medium, and medium-narrow clearances. Scanning electron microscopy showed that a narrow clearance treatment reduced the smoothness of the granule surface, and also reduced the starch granule birefringence. X-ray diffraction showed that the crystallinity decreased with decreasing milling clearance. Differential scanning calorimetry showed that the peak temperatures were similar at all levels, and the gelatinization enthalpy declined with decreasing crystallinity. The results suggest that sago starch can be recovered from SPW using micro powder milling, and the treatment, especially at narrow clearance, disrupts the crystalline regions of sago starch.