Studies On The Preparation And Functions Of Crocodile Meat Peptide Chelated Calcium

Crocodiles have high economic value,but at present,the use of crocodile resources is mainly in crocodile leather,crocodile meat consumption and as ornamental animals.With the gradual rise of crocodile breeding industry,it's particularly important to develop new crocodile products and fully exploit the value of crocodiles.In this study,crocodile meat was used as raw material to prepare crocodile meat peptide(CMP)by enzymatic hydrolysis,then CMP and calcium chloride were used to prepare CMP-Ca.Physicochemical property,antioxidant capacity,cytotoxicity and calcium supplement effect of CMP-Ca were studied to provide theoretical basis for the development of new crocodile products.The research work and findings were summarized as follows:The preparation conditions of CMP were optimized by single factor experiment with the degree of hydrolysis as the index,and the optimal enzymatic hydrolysis conditions were as follows:for papain,solid-liquid ratio was 1:8,pH was not adjusted,hydrolysis temperature was 60?,enzyme-substrate ratio was 3%and hydrolytic time was 5 h.The molecular weight distribution range of CMP was measured by ultra performance liquid chromatography-mass spectrometry,and the majority of CMP were short peptides and free amino acids with molecular weight less than 800Da.On the basis of single factor experiment,response surface experiment was designed to optimize the preparation conditions of CMP-Ca with chelating rate as index,and the best chelation conditions were as follows:mass ratio of peptide-calcium was 11.4,chelating time was 107min,chelating temperature was 50?,chelating pH was 5.67.To explore the changes of CMP to CMP-Ca properties.CMP powder was mostly flaky with smooth surface,while CMP-Ca powder was irregular particle with rough surface and many holes.The median grain size of CMP was 17.756 ?m,while the grain particle size of CMP-Ca was 24.925 ?m.By comparing the infrared spectra of CMP and CMP-Ca,it's speculated that the chelating form of CMP-Ca was Ca2+ interacting with the amino nitrogen atoms and carboxyl oxygen atoms of CMP.Physicochemical properties of CMP-Ca were determined,and the results were:the protein content of CMP-Ca was 78.68%,and there were also constants and trace elements needed by human body,and it was not contain harmful heavy metal elements and was rich in various amino acids.To investigate the biological function of CMP-Ca and conduct toxicity experiments.CMP-ca has certain antioxidant capacity in vitro,and has scavenging ability for ABTS+·.DPPH·,hydroxyl free radical and ·O2-,and the scavenging ability was positively correlated with the concentration.The results of MTT experiment with human hepatocyte LO2 showed that CMP-Ca hadn't cytotoxicity.CMP-Ca was administered to C57BL/6 mice by gavage,and the indexes were detected one month later.The results showed that CMP-Ca hadn't adverse effect on the normal growth and organs of C57BL/6 mice,and had a good calcium supplement effect with high calcium absorption rate.CMP-Ca was administered to mice after osteoporosis was induced by tretinoin,and the indexes were tested one month later.The results showed that CMP Ca could significantly improve the osteoporosis of mice.