하이드록시프로필화 후 가교화시킨 복합변성 쌀 전분의 이화학적 특성

Physicochemical properties of hydroxypropylated and cross-linked (HPCL) rice starch were investigated. Dual modification of rice starch was carried out by hydroxypropylation using propylene oxide (2, 6, and 12%) and then cross-linking using phosphorus oxychloride (0.005% and 0.02%). Swelling power of dual-modified rice starch increased at lower temperature (60°C) than that of native rice starch (70°C). HPCL rice starch showed slightly lower solubility (1.6-6.1%) than native rice starch (2.2-13.8%). Solubility and swelling power tended to gradually increase with increasing phosphorus oxychloride contents. RVA pasting temperature (66.2-70.8°C) and peak viscosity (160.6-171.1 RVU) of HPCL rice starch were lower than that of those of native starch (71.3°C, 190.4 RVU) and decreased with increasing propylene oxide concentration. DSC thermal transitions of HPCL rice starches shifted to lower temperature and show less amylopectin melting enthalpy (11.8-9.8 J/g) than that of native rice starch (11.9 J/g). Overall, physicochemical properties of HPCL rice starches were highly dependent on hydroxypropylation rather than cross-linking.