Effects of fucoidan and ferulic acid on potato starch: Pasting, rheological and retrogradation properties and their interactions

The study aimed to investigate the effects of fucoidan (FU) and ferulic acid (FA) on the pasting, thermal, rheological, microstructural and moisture migration properties of potato starch (PS) gels. Pasting results showed that the presence of FU and FA significantly enhanced the thermal stability and resistance to breakdown, and inhibited the stickiness of starch, with the ternary system (PS-FU-FA) showing the best performance. Thermodynamic results indicated that the PS-FU-FA ternary system markedly reduced the retrogradation rate, with FA counteracting the aging phenomenon induced by FU. Rheological tests revealed that all gel systems exhibited weak gel and pseudoplastic fluid behaviors. FA increased the elasticity of PS gels, while FU and FU-FA reduced the viscoelasticity and thickening coefficient of PS, and improved its resistance to shear thinning. Scanning electron microscopy, infrared spectroscopy and low-field nuclear magnetic resonance results suggested that the changes in the above results were due to the interactions among FU, FA and PS, which increased the short-range order structure, and made the microstructure more uniform, compact and continuous, unfavorable for moisture movement, with better water-holding capacity and thermal stability. This study confirmed that the addition of FU and FA had positive effects on the gel properties of PS, providing new insights for the design strategy of starch-based foods, and promoting the practical application of FU, FA and PS in food industry.