Synergistic high-pressure homogenization–ultrasound modification of wheat starch–linoleic acid complexes: Structure, slow digestibility, and emulsion stability

Wheat starch–linoleic acid (WS–LA) complex is a type 5 resistant starch (RS5) with potential for developing low glycemic index (GI) foods enriched in ω-6 fatty acids. In this study, WS–LA complexes were prepared via high-pressure homogenization (HPH, 100 MPa, 0, 3, 5, 10 cycles) and subsequently ultrasound-treated (UT, 600 W, 10 min), yielding the UT (0 cycles), HPH-UT3, HPH-UT5, and HPH-UT10 samples. The formation of V -type inclusion complexes was confirmed by XRD and solid-state NMR. Among all complexes, the HPH-UT5 sample exhibited the best slow digestion performance, with RS content increasing from 10.54% (native starch) to 18.05%, and the slowly digestible starch content reaching the maximum of 16.60% ( p  < 0.05). In addition to its nutritional benefits, the HPH-UT10 sample demonstrated potential as a starch-based Pickering stabilizer, with emulsions showing no phase separation over 28 days at room temperature. Overall, the HPH-UT sequence offers an effective strategy for preparing RS5 with enhanced resistant starch content and emulsion-stabilizing capability, providing a promising route toward low-GI foods enriched with ω-6 fatty acids.