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Adsorption And Concentration Of Histidine-containing Dipeptides By Functionalized Mesoporous Material

Posted on:2017-05-29Degree:MasterType:Thesis
Country:ChinaCandidate:J Y ZhuFull Text:PDF
GTID:2311330512970233Subject:Food Science
Abstract/Summary:PDF Full Text Request
Carnosine (Car, ?-alanyl-L-histidine) and anserine (Ans, ?-alanyl-L-1-methylhistidine) are commonly present in mammalian tissue, particularly in skeletal muscle. Car and Ans exists in meat products, and meat-derived extracts and wastes which could be used for cheap recovery of histidine-containing dipeptides. Mesoporous silica SBA-15 has received substantial attention. Owing to its large surface area, narrow pore size distribution, and superior pore structure, SBA-15 has proved to be excellent solid supports for protein and peptides separation. This paper aims to design a kind of functionalized mesoporous silica due to the imidazole group on the histidine-containing dipeptides, study the adsorption characteristics of the materials and study adsorption dynamics and isothermal adsorption of histidine-containing dipeptides.Firstly, this study developed and validated a high performance liquid chromatography for determination of histidine-containing peptides. Carnosine and anserine of different species and different parts in the same specie were detected by HPLC with OPA as reagent. It was found that there were abundant content in chicken, which act as low-value food stuff especially laying hens. Hence, laying hens are the good source of separating HCDPs. Use dicing, cracking, stirring, ultrasonic, boiling and enzymatic hydrolysis method to extract HCDPs, cracking-stirring method can extract the most HCDPs in the chicken and with the least impurities. After two-step separation by ultrafiltration (1000 Da) and nanofiltration (500 Da), the content of HCDPs was 60% in extraction determined by the amino acid analysis.Secondly, using two-step way to synthesis of metal doped mesoporous materials. Functionalized SBA-15 with carboxyl modifier (CES), characterization by XRD, TEM, BET. It was found that S-COOH remained the same structure with SBA-15, hexagonal structure (p6mm). While, with the increasing radio of CES and TEOS, the channel damaged, collapsed. S-COOH still exhibited a type ? isotherm and a type H1 hysteresis loop, but the pore volume, specific surface area also decreased. Synthesis the metal doped SBA-15, characterization by XRD, BET, ICP. It showed that the concentration of added metal should be within a certain range, high metal concentration (100 mmol/L), mesoporous channel might be congested.Thirdly, carboxyl group functionalized mesoporous silica of SBA-15 was synthesized to facilely incorporating NiO, ZnO and CaO for Car extraction. Among these, Ni/SBA-15 has the highest adsorption capability. The correlation between the most significant parameters was optimized, and the effects of these parameters on the adsorption efficiency of Car were investigated. Due to the adequate pore size and high Ni loading, the adsorption capacity of Car approached as high as 0.69 mmol/g. The excellent adsorption characteristics of the current adsorbents toward Car were preserved in a wide pH window and could be hardly infected by the background salts.Last, the pseudo-second-order rate equation effectively described the uptake kinetics (R2 between 0.983 and 0.999). The Langmuir model (R2 between 0.994 and 0.998) exhibited a better fit to adsorption isotherm than the Freundlich model.Therefore, nickel species within functionalized SBA-15 is a kind of efficient materials for recovering histidine-containing peptides from egg-laying hens and makes it a favorable candidate as chromatographic column materials for HCDPs analysis.
Keywords/Search Tags:Histidine-containing Dipeptides, Carnosine, Mesoporous Material, Adsorption, Adsorption Kinetics
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