Multiscale structure, physicochemical properties, and in vitro digestibility of corn starch complexes co-gelatinized with guar gum and its enzymatic hydrolysates: A multiple factor analysis study

Partially hydrolyzed guar gum (PHGG), an enzymatic hydrolysate of guar gum (GG), confers various physiological benefits, including hypoglycemic effects and gut microbiota regulation. The molecular weight of PHGG is identified as a key determinant of the pasting properties of corn starch (CS). This study evaluated the effects of GG and PHGG with different molecular weights (34.66 kDa, 25.17 kDa, 14.71 kDa, and 8.93 kDa) on the physicochemical and digestion properties of CS. The results showed that GG increased the peak viscosity (PV), trough viscosity (TV), final viscosity (FV), apparent viscosity, dynamic moduli (G' and G″), and mean volume (MV) of CS gel, but reduced its thermal stability. In contrast, PHGG demonstrated distinct effects by effectively inhibiting starch swelling and enhancing the thermal stability of the gel system. High-molecular-weight PHGG formed a gel characterized by larger, irregularly distributed honeycomb-like pores, which significantly reduced gel hardness (<i>P</i> < 0.05). Furthermore, with the reduction in PHGG molecular weight, the slowly digestible starch (SDS) content in the CS-PHGG gel decreased significantly, while the resistant starch (RS) content increased (<i>P</i> < 0.05). Multiple factor analysis (MFA) revealed strong correlations between the physicochemical properties and structural characteristics of the gels. These findings demonstrate that PHGG modulates starch gel properties, which may provide new insights for the design of starch-based foods with tailored nutritional or functional properties.