Effects of isolation methods on physicochemical properties of defatted starch from the acorn (Quercus brantii)

This study explores the innovative combined effects of alkaline isolation with ultrasound pretreatment on the physicochemical properties of acorn (Quercus brantii) starch. The optimal pH for maximizing the yield of alkaline-isolated acorn starch (AAS) was determined, followed by comparison with alkaline-isolated defatted acorn starch (ADAS), ultrasound-pretreated acorn starch (UAS), and ultrasound-pretreated defatted acorn starch (UDAS). The results demonstrated substantial improvements in yield and purity, with the highest yield (68.97 ± 0.16 %) achieved at pH 9. ADAS showed high purity, with protein and fat contents of 1.82 ± 0.07 % and 0.025 ± 0.02 %, respectively. UDAS exhibited superior swelling power, solubility, and turbidity, indicating enhanced functional properties. Scanning Electron Microscopy (SEM) revealed variations in granule sizes across treatments, from 12.42 μm (ADAS) to 10.72 μm (UDAS). X-ray diffraction analysis showed C-type patterns with crystallinity ranging from 31.25 % (ADAS) to 26 % (UAS). Thermal analysis demonstrated UDAS had the highest peak viscosity and lowest thermal parameters. Texture analysis indicated that AAS formed a softer gel, while ADAS displayed greater hardness and gumminess. These findings highlight the effectiveness of combining alkaline isolation with ultrasound pretreatment to improve acorn starch quality for sustainable applications in food and biotechnology.