Effects of chlorogenic acid on the physicochemical properties, 3D printing characteristics, and anti-digestive properties of sweet potato starch.

This study investigated the effects of chlorogenic acid (CA) with different levels (0.5 %-2.0 %) on the printing accuracy, micro-structure, rheological properties, thermodynamic properties, texture, digestion characteristics, and other indicators of sweet potato starch (SPS). Results showed that the printed SPS products with 0.5 % CA exhibited the best structural recovery properties and printing accuracy, with a thixotropic recovery rate of 98.37 %. The addition of CA significantly increased the gelatinization enthalpy of SPS and free water content. The SPS gel with 2.0 % CA exhibited the poorest water-binding ability with free water content of 3.49 %. SPS with higher levels of CA displayed less lamellar structure denser network structure, and more thickened pore walls. The printed SPS product with 2.0 % CA had the lowest hardness (173.64 g), elasticity (0.74), adhesiveness (89.24), and chewiness (65.93). The content of double helix structure in SPS with 0.5 %-1.5 % CA was significantly lower than that in the SPS without CA. All the addition proportions of CA significantly increased the relative crystallinity of SPS, and the SPS with 2 % CA had the highest relative crystallinity (19.96 %). Additionally, CA significantly enhanced the antioxidant ability of printed SPS products. All the levels of CA significantly reduced the RDS content and increased the RS content in the printed SPS products. The RS content in SPS with 2.0 % CA increased by 25.44 %, compared with SPS alone. Therefore, this study provides a theoretical basis for the development of polyphenol-enriched 3D-printed SPS diets for the populations with hyperglycemia and obesity.