Potato Protein Peptides as a Serum-Reducing Supplement for MDCK Cell Culture Medium

Food-derived peptides produced by enzymatic hydrolysis have attracted interest as functional biomaterials for cell culture. In this study, potato protein was hydrolyzed using Flavorzyme to prepare potato protein peptides (PPPs), which were characterized by degree of hydrolysis, SDS-PAGE, free amino acid analysis, and LC-MS/MS-based peptide identification. Among the 101 identified peptide sequences, 66 (65.35%) had molecular weights ranging from 500 to 1000 Da. And were subsequently evaluated for their effects on MDCK cell growth, metabolism, and cryopreservation. The optimal PPPs concentration for MDCK culture was 1 g/L. At passage 9, the PPPs + 5% NBS group showed the highest CCK-8-derived estimated cell density (9.11 × 10⁴ cells/mL), with a doubling time of 15.71 h and a specific growth rate of 0.0163 ± 0.0002 h^-1. These values were significantly higher than those in the 5% newborn bovine serum (NBS) control (p < 0.05) and comparable to the 10% NBS control (p > 0.05). The PPPs + 5% NBS group exhibited glucose and lactate concentration profiles distinct from those of the 5% and 10% NBS controls during culture. In short-term cryopreservation tests, passage-10 cells maintained normal proliferation and morphology. PPPs supplementation was also associated with favorable post-thaw cell recovery in serum-containing cryopreservation media. Overall, these findings suggest that PPPs may serve as promising serum-reducing supplements for MDCK cell culture and cryopreservation.