The shelf life of proteins in-vitro is limited by their susceptibility to various degradation processes. This study demonstrates that starch can extend protein stability by selectively removing non-proteolytic degradation products. Using NMR spectroscopy, we show that starch effectively scavenges degraded protein impurities while preserving the native protein structure as indicated by nearly identical HSQC spectra for fresh intact protein and degraded protein samples treated by starch. The interaction is primarily electrostatic, with starch exhibiting a strong affinity for positively charged amino acids such as arginine, lysine, and histidine. Molecular dynamics simulations further reveal that amylose stabilizes these amino acids through hydrogen bonding and charge-dipole interactions, reducing backbone flexibility. This low-cost, easy-to-implement approach holds promise for improved protein stability and has broad pharmaceutical applications.