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The regulatory effects of phosvitin phosphopeptide (PPP) and its calcium chelate (PPP-Ca) on osteoblast differentiation in the co-culture system of osteoblast (MC3T3-E1) and osteoclast precursor (RAW264.7) were investigated. Cytotoxicity, alkaline phosphatase (AKP) activity, tartrate-resistant acid phosphatase (TRAP) activity and TRAP staining were analyzed. The mRNA expressions of RANKL/OPG pathway-related proteins in osteoblasts were further studied by RT-PCR. The results showed that PPP and PPP-Ca increased theAKP activity in the MC3T3-E1 system by 9.5% and 12.7%, respectively. In the MC3T3-E1 system, PPP and PPP-ca increased the mRNA expression levels from 0.92 to 1.25 and 1.39, respectively, for OPG, and from 1.00 to 1.23 and 1.45, respectively for RANKL. The results of this study showed that PPP and PPP-ca could effectively promote the differentiation of osteoblasts. The experimental results provide a research basis for further exploration of the role of phosphopeptides in the multi-cell model system and the development of functional activity of phosphopeptides. [ABSTRACT FROM AUTHOR]

Natural antioxidants derived from agricultural by-products have great promise and ecological advantages in the treatment of oxidative stress-related diseases. The eggshell membrane (ESM) from hatched eggs, i.e., the hatched ESM, is a globally abundant agricultural byproduct, and its high-value utilization has been rarely studied compared to the well-studied ESM from fresh eggs. In this research, we systematically characterized the hatched ESM as a novel source of antioxidant hydrolysates and explored their potential role in H2O2-induced human chondrocytes. The results showed that the hatched ESM is a protein-rich fibrous mesh material with a significantly different structure and composition from those of fresh ESM. Enzymatic hydrolysis of hatched ESM can produce antioxidant hydrolysates rich in low molecular weight (MW) peptides, which mainly derived from the Lysyl oxidase homolog by Nano-LC-MS/MS analysis. The peptide fraction with MW < 3 kDa (HEMH-I) exhibited the highest DPPH radical scavenging, Fe2+-chelating, and Fe3+-reducing abilities. In H2O2-induced human SW1353 chondrocytes, HEMH-I treatment significantly increased the cell viability and ameliorated oxidative stress, inflammatory response, and cartilage matrix degradation by reducing the level of ROS, matrix metalloprotease 3 (MMP3), MMP13, and IL-6, and by promoting the expression of SOD and type II collagen, potentially through activating the cellular Keap1/Nrf2/HO-1 pathway. This study provides a theoretical basis for the value-added application of hatched ESM waste to produce antioxidant hydrolysates and indicates their potential as functional food and pharmaceuticals. [ABSTRACT FROM AUTHOR]

Summary: Heat treatment will affect the nutritional properties and potential bioactivity of food materials. The aim of this work was to evaluate the effect of different thermal treatment (4, 56, 65 and 100 ℃) and invitro gastrointestinal digestion on the antioxidant activity of egg white hydrolysate. The results demonstrated that egg white hydrolysate treated at 65 ℃ exhibited the highest antioxidant. Remarkably, the simulated digestion significantly increased antioxidant activity of egg white hydrolysate. Furthermore, we identified twenty‐four potential antioxidant peptides by performing mass spectrometry and bioinformatic analysis. Six peptides were selected based on the activity prediction score of the online tool. The results showed that P6 (ACPECPK) possessed the most outstanding antioxidant properties and had low cytotoxicity and allergenicity. Bioinformatics technology combined with biochemical assays may offer a way for discovering novel antioxidant peptides from different kinds of food under various heat treatment conditions. [ABSTRACT FROM AUTHOR]