Preparation And Purification Of Antioxidant Peptides From Flatfish(Paralichthys Olivaceus) Skin

The whole study was aimed at investigating the preparation and purification ofantioxidant peptide from flatfish skin. On this basis, the annual output of10tons ofcollagen peptides preparation process was designed, and two new for ms of collagenpeptide products were developed.(1) The pretreatment of flatfish skin was investigated, comparing the defattedeffect of various organic solvent, isopropyl alcohol: diethyl ether=1:1(v/v) was electedand the optimal technological parameters were: time36hours, temperature20℃,solid/liquid r atio1:10. Comparing the non-collagen removal effect of various reagents,0.1M NaOH was elected, and the optimal technological parameters were: solid/liquidratio1:30, time36h, temperature10℃.(2) The preparation of collagen peptides from flatfish was investigated, Takingdegree of hydrolysis(DH) and peptides yield(PY) as index, neutrase:trypsin=1:1(U/U)was elected as hydrolase and4hours as hydrolysis time for preparation of collagenpeptides. The optimal hydrolysis conditions for collagen peptides were investigatedby respo nse surface methodology (RSM) to explore pH, temperature, enzyme/substrate (E/S) on DH and PY. The optimum values were determined as follows: pH7.3, temperature51.8oC and E/S2776U/g. Under the optimal hydrolysis conditions,the relative error between the predicted value and experimental value of DH and PYwere0.67%and1.65%, respectively. The molecular weight of collagen peptides wasdistributed between900~1600Da. And amino acids associated with antioxidantactivity were rich in collagen peptides. The antioxidant activities of collagen peptidesfrom flatfish skin showed that collagen peptides had certain scavenging free radicalactivities (hydroxyl radical39.8%, superoxide anion radical32.2%, DPPH15.38%at5mg/ml, respectively), reducing power, lipid peroxidation inhibition, and ferrousion-chelating activity.(3) The preparation of antioxidant peptides from flatfish was investigated, TakingDPPH scavenging activity as index, trypsin was elected as hydrolase for preparationof antioxidant peptides. The optimal hydrolysis conditions for antioxidant peptideswere investigated by response surface methodo logy (RSM) to explore pH,temperature, E/S on DPPH scavenging activity. The optimum values were determined as follows: pH6.62, temperature48.2oC and E/S2776U/g. Under the optimalhydrolysis conditions, the relative error between the predicted value and experimentalvalue of DPPH scavenging activity was1.04%. The molecular weight of collagenpeptides was distributed between900~1600Da. And amino acids associated withantioxidant activity were rich in collagen peptides. A novel antioxidant peptide wasisolated from antioxidant peptides by Sephade x G-15gel filtration chromatography,Sephade x G-10gel filtration chromatography and RP-HPLC. The molecular weightmeasured by MS was1025.9Da, may be octapeptide.(4) The parameters of the preparation of collagen peptides were amplified.Results showed that peptides yield was60.82%and purity was75.05%. Themolecular weight of collagen peptides manufactured by amplified experiment wasdistributed between500~1600Da. The economic benefit of annual output of10tonscollagen peptides was analyzed, showing that annual sales income5million yuan wasobtained and net profit was3.224million yuan.(5) Two new for ms of collagen peptide products were developed：Oral liquidcontaining collagen and collagen effervescent tablet were produced.