Heat-moisture treatment-induced starch-protein structural reorganization in whole highland barley flour regulates noodle quality and starch digestibility.

Whole highland barley flour (WHBF) has attracted increasing attention owing to its superior nutritional profile, but its poor processing properties limit its application in noodle production. This study investigated how temperature and moisture during heat-moisture treatment (HMT) regulate the structure of WHBF and consequently affect noodle quality and starch digestibility. HMT increased swelling power, solubility, and pasting stability of WHBF, while inducing minor changes in protein secondary structure. Starch structural order was enhanced at 80 °C but disrupted at 120 °C, and higher moisture intensified these structural changes. The results revealed that HMT promoted starch encapsulation within a more continuous protein network and improved water distribution, leading to reduced cooking loss, enhanced textural properties, and low starch digestibility. Overall, HMT at 100 °C and 25% moisture achieved the best performance, reducing cooking loss to 8.23%, increasing springiness to 0.856, breaking distance to 50.89 mm, and resistant starch to 41.46%. Pearson correlation analysis further showed that glutenin macropolymer was closely related to noodle quality attributes, whereas starch crystallinity was positively correlated with resistant starch formation. These findings provide new insights into HMT-induced structural reorganization of WHBF and support the development of high-quality, slow-digesting WHBF noodles.