Egg yolk phosphopeptides exhibit potent osteogenic activity over ordinary egg yolk peptides in MC3T3-E1 cells

As osteoporosis and related bone disorders continue to rise in prevalence, identifying bioactive components that enhance osteoblast function has emerged as a key priority in nutritional and bone health research. In this context, the present study compared the effects of egg yolk peptides (EYP) and egg yolk phosphopeptides (EYPP) on osteoblast differentiation and mineralization using MC3T3-E1 Subclone 14 cells, by evaluating alkaline phosphatase (ALP) activity, mineralized nodule formation, and their structural properties (e.g., phosphorus content, amino acid composition). Results showed distinct molecular differences: EYPP had a significantly higher phosphorus content (2.23% vs. 0.45% in EYP) and distinct amino acid composition, particularly a higher proportion of phosphorylated serine and small molecular weight peptides (<1000 Da). Functionally, EYPP showed a stronger concentration-dependent promotion of ALP activity during early osteoblast induction. Specifically, the 0.8 mg/mL EYPP group increasing ALP activity by 18.75%, 14.47%, and 7.91% at 3, 7, and 14 days, respectively. These effects were more pronounced than those of EYP, whose promoting effect weakened over time. In mineralization, alizarin red staining revealed that 0.8 mg/mL EYPP significantly enhanced mineralized nodule formation, with its absorbance being 8-fold higher than the control at 14 days, whereas EYP showed minimal effect until 21 days. These findings highlight EYPP as a more potent promoter of osteoblast differentiation and mineralization compared to EYP. • EYPP is more osteogenic than EYP in MC3T3-E1 via ALP promotion. • EYPP enhances mineralized nodule formation more effectively than EYP. • EYPP's superiority is due to higher phosphorus and distinct amino acids.