Favored CH-π interaction between enzymatically modified high amylose starch and resveratrol improves digestion resistance

Abstract

Starch-stilbene polyphenol complexes, a novel form of resistant starch (RS), have received considerable attention due to their potential health benefits. To enhance the functionality of this type of complex, we examined the interactions between resveratrol (RA) and high-amylose starch with different molecular weights, achieved through enzymatic modification followed by high-pressure homogenization (HPH). We examined how these interactions affect the digestibility and ordered structures of the complexes. Our findings reveal that, notwithstanding the inhibition of double helix and B-type crystalline structure formation, RA-starch complexation markedly boosted single helix content, V-type crystalline structure formation, and aggregate structure density. These effects contributed notably to increased RS content. Interestingly, the formation of the V6-type crystalline structure within the complexes was primarily facilitated by the CH-π interaction between the aromatic rings of RA and the C–H of starch, rather than conventional hydrogen bonding and electrostatic forces. The strength of the CH-π interaction increased with higher amylose content and lower molecular weight of the starch, achievable through a 12-h pullulanase hydrolysis followed by a 2-h α-amylase hydrolysis. The resulting HPH-Pα2-RA complexes exhibited remarkable levels of the V-type crystalline structure and RS content, reaching up to 25.45% and 57.37%, respectively. Overall, this study offers valuable insights into the design of starch-polyphenols complexes with a high RS content.