Effects of dry heat and heat-moisture treatment of refined buckwheat core flour on oil content of fried instant noodles: The view from protein structural and microstructure.

Reducing oil content without compromising texture remains a major challenge in developing healthier fried instant noodles. This study investigated whether dry heat treatment (DHT) and heat-moisture treatment (HMT) could regulate the structural properties of refined buckwheat core flour and thereby reduce oil content in fried instant noodles. Refined buckwheat core flour was treated by DHT or HMT and incorporated into wheat flour at 15% substitution. Both treatments effectively reduced oil content under appropriate treatment conditions, but were associated with different structural responses. Moderate DHT promoted paggregation, allowing the buckwheat particles to interact more effectively with wheat gluten and form a more stable composite structure through disulfide cross-linking. This more stable structure may limit the formation of structural defects and open spaces, thereby reducing final oil retention. In contrast, HMT restricted starch swelling and molecular leaching while improving the structural stability of the starch-protein matrix, thereby promoting the formation of a network structure associated with reduced oil retention. These findings highlight heat-treated refined buckwheat core flour as a potential structural regulator for developing lower-oil multigrain fried instant noodles.