Sweet potato starch noodle enriched with purple sweet potato anthocyanins: Improving anthocyanin retention and noodle quality by adding citrus peel pectin

Due to chemical instability, anthocyanins easily degrade during processing and cooking. This study investigated whether citrus peel pectin (CP) could increase purple sweet potato anthocyanin (PSPA) retention in sweet potato starch noodles. Particle size analysis, ζ -potential measurements, and small-angle X-ray scattering confirmed that CP formed nanoscale complexes with PSPA, which showed heterogeneous multilayer adsorption on CP fitting the Freundlich isotherm model. Adding 0.5% and 3% CP significantly increased PSPA retention from 37.82% to 48.75% and 52.24%, respectively. CP and PSPA altered starch structure and noodle gel network, modifying texture and tensile properties without affecting cooking yield or loss. PSPA reduced hardness and chewiness of noodle. Notably, 0.5% CP combined with PSPA maximized tensile force and extensibility of cooked noodles. This study suggests CP effectively elevates PSPA retention via complex formation, with 0.5% CP balancing PSPA retention and noodle quality, offering insights for improving pigmented starch products with natural polysaccharides.