Immunostimulatory effect of egg yolk phosvitin phosphopeptides produced by high-temperature and mild-pressure pretreatment and enzyme combinations in RAW 264.7 cells via TLR2/MAPK signaling pathway

•Phosvitin phosphopeptides (PPPs) increased NO production by inducing the mRNA expression of iNOS in RAW 264.7 cells.•PPPs exhibited immunostimulatory activities by accelerating the mRNA expression and secretion of pro-inflammatory cytokine.•The activation of the TLR2-mediated MAPK signaling pathway was involved in the immune-stimulating effects of PPPs.