Heat-moisture treatment induced structural changes and their impact on the quality of extruded brown rice noodles

Brown rice noodles face processing and quality limitations that hinder their broader application. Heat-moisture treatment (HMT) is a hydrothermal modification method conducted at low moisture content and elevated temperature without inducing complete starch gelatinization.This study applied HMT to modify brown rice flour and investigated its effects on the quality of extruded brown rice noodles. Increasing temperature and moisture content raised apparent amylose levels, enhanced crystallinity, and promoted structural ordering. These changes contributed to reduced water solubility index, swelling power and a denser, more organized noodle structure. Consequently, textural properties improved significantly, with higher hardness, springiness, and cohesiveness, alongside lower adhesiveness. Cooking performance was also enhanced: cooking loss decreased from 13.44% (control) to 9.88% (20% moisture, 80 °C group), and the breakage rate dropped from 12.75% to 1.75%. Moreover, resistance to digestion improved, with noodles treated at 100 °C and 20% moisture exhibiting the lowest predicted glycemic index (69.29) and the highest resistant starch content (41.82%). This study provides a theoretical basis for developing high-quality, nutritionally improved extruded brown rice noodles through HMT.