High moisture extrusion induced interaction of Tartary buckwheat protein and starch mitigating the in vitro starch digestion

This study investigated the effects of adding 4–20 % Tartary buckwheat protein (TBP, with a purity of 93.35 %) on the structural, thermal, and digestive properties of Tartary buckwheat starch (TBS) by high moisture (60 %) extrusion. The added TBP embedded and enwrapped the starch matrix, which formed protein–starch complexes. After adding 4 %–20 % TBP, the shear degradation of AP decreased. Conversely, the shear degradation of AM chains increased. The addition of TBP promoted the retrogradation of starch in extrudates, enhancing their short- and long-range ordered structures. Compared with extruded TBS, extrudates contained TBP showed a reduction of gelatinization enthalpy, a high content of resistant starch, and a lower starch digestibility. These findings provided an insight into the protein–starch interactions under high moisture extrusion, which would promote the advancement of starch-based foods with high TBP content. [Display omitted] •Adding Tartary buckwheat protein (TBP) inhibited the shear degradation of amylopectin.•Extrusion with adding TBP led to a shear scission of amylose chains.•Extrudates containing TBP showed higher short- and long-range orderliness.•Adding TBP slowed the starch digestion of extrudates with higher resistant starch.