The Establishment Of Peptides Extraction Technology From The Skin Of Rana Chensinensis And The Preliminary Development Of Cosmetics With The Peptides

Due to the high biological activity,peptides is play an active role in medicine and commerce.Rana chensinensis is a well-known economic species in the northeast of China,with many biological activity factors in its skin,it become a research hotspot.In this study,we studied the extraction method of peptides from the Rana skin through enzymatic hydrolysis on the basis of our previous studies.The effects of different pretreatment conditions on the preparation of the skin of Rana chensinensis were studied by using peptide yield,molecular weight distribution,solubility and antibacterial activity as indicators.The best course of this experiment is the digestion time of the Rana skin is 4 hours.Under this process,then the enzymatic hydrolysis of the crude extract was separated by membrane separation technology to obtain nanofiltration concentrate,vacuum freeze-dried and obtained lyophilized powder.The peptides showed a characteristic absorption peak at 220 nm,a small molecular weight distribution range,good solubility,and had antibacterial activity against Escherichia coli and Staphylococcus aureus.We developed 2 skin care products(gel and cream)with the peptides as cosmetics material.The quality standards and stability of these two products were studied by accelerated stability tests and microbiological examination.The p H value of the gel and cream prepared in this study was 6.11 and 6.19,respectively,which was in accordance with the national standard.The heat-resistant,cold-resistant and centrifugation tests showed that the gel and cream is stable while at high temperatureof 37 ?,4 ? environment;the results of microbiological tests meet the requirements.The optimum proportion of blank nanoemulsion was screened by emulsifying agent emulsifier titration method.We took every factors of each functional ingredients(moisturizing factor Betaine,whitening ingredients arbutin and the peptides from Rana skin)into account,such as the efficacy,the cost of production and the amount added in cosmetics and determined the biological properties of Rana peptides nanoemulsion.Results are:thehe nanoemulsion keep steady in conditions of temperature,centrifugal and light.Besides,it was identified there is no acute toxicity,no allergenicity,and no stimulation by skin safety experiments.