LAUSR

BACKGROUND Adequate calcium intake is necessary to prevent osteoporosis which poses significant public health challenges. The natural bioactive peptides calcium chelates have been regarded as superior calcium supplements. Microalgae peptides are the potential candidate for protecting from bone loss in osteoporosis. This study aimed to prepare the microalgae calcium-chelating peptides from four microalgae proteins (MPs) and assess their osteogenic activities in osteoporosis-like zebrafish. RESULT After in vitro gastrointestinal digestion, 4.42% Chlorella pyrenoidosa protein (CPP), 2.74% Nannochloropsis oceanica protein (NOP), 6.07% Arthospira platensis protein (APP), and 10.47% Dunaliella salina protein (DSP) were retained. The calcium-chelating capacities of four microalgae protein hydrolysates (MPHs) ranged from 14.10 ± 7.16% ~ 34.11 ± 9.34%. CaCl2 addition increased the maximum absorption peaks, absorption intensities and particle sizes of MPHs. Calcium chelating MPHs showed stronger osteogenic activities than MPHs in the osteoporosis-like zebrafish model with the significantly increased mineralized tissue area and integrated optical density (IOD). CONCLUSION Microalgae proteins have a favorable digestibility. Among the four MPHs, Nannochloropsis oceanica protein hydrolysates (NOPH) showed the highest calcium-chelating capacity, which might be due to its high degree of hydrolysis after in vitro digestion and great content of Ser, Tyr, Thr, Asp and Glu. The absorption intensities and particle sizes of MPHs both increased after calcium addition. MPHs treatment could reverse the Dexamethasone (Dex)-induced osteoporosis of zebrafish, and MPHs-Ca chelates showed higher osteogenic activity in osteoporosis-like phenotype zebrafish. This article is protected by copyright. All rights reserved.