The Impact of Different Molecular Weight Hyaluronic Acid on Pasting, Rheological and In Vitro Digestibility of <i>Cyperus esculentus</i> Starch

Hyaluronic acid (HA), a naturally occurring polysaccharide recognized for its health benefits, has been approved for use in the food industry as a food additive and nutraceutical. This study aimed to explore the influence of HA with varying molecular weights (Mws) on the pasting, rheological properties, and in vitro digestibility of Cyperus esculentus starch (CES). High Mw HA (HHA) exhibited a more pronounced inhibition on starch solubility (15.60%-9.51%) and leaching of amylose (11.63%-8.44%) compared to low Mw HA (LHA), while enhancing starch swelling power (28.32-42.99 g/g). Furthermore, HHA increased the peak viscosity (362.50-460.40 mPa s) of CES and decreased both breakdown and setback values. All HA-CES mixtures demonstrated pseudoplastic behavior. Fourier transform infrared spectroscopy analysis revealed no emergence of new absorption peaks, and the short-range order degree in starch with HA reduced from 0.853 to 0.843. Scanning electron microscopy images indicated a more homogeneous lattice structure with increasing Mw of HA. In vitro digestibility experiments showed that the incorporation of HA slowed down the enzymatic hydrolysis of starch. In conclusion, HA improves the functional attributes of CES, with a more pronounced effect observed at higher Mw, thus providing valuable insights into the potential application of HA in starch-based foods.