Study On The Preparation And Activity On Antihypertensive Peptide From Casein Protein

Casein is the most abundant protein in milk and is also essential amino acid for individual growth.Recently,many researches demonstrated that casein many also be biologically active peptide.ACE inhibitiory peptide from casein has received the most attention for its safe and no side effects.In the present study,bovinr caseins as the raw material are hydrolysed with protease. Ultrafiltration and desalinisation of hydrolysis product were studied.The aiga antihyoertensive peptides with high inhibitory activity against angiotensive converting enzyme were separated,and model animal tests verified significant antihypertensive effect.In the study,alkaline protease was used to hydrolyze casein for the production of antihypertensive peptide.The hydrolysis conditions of alkaline protease was optimized by the single factor experiment and the orthogonal design.The optimal hydrolysis conditions of alkaline protease were:substrate concentration15%,enzyme concenmation0.15%,pH9.5,50℃.At the optimal hydrolysis conditions,the DH was23.15%,the ACE inhibitory was51.82%.The mixture pf peptides was separated by ultrafiltration membrane(PES) of MW cut-off lOkDa and3kDa.The result showed that ultrafiltration could increase the ACE inhibitory activities of casein hydrolysates.However,permeates of3kDa membrane showed higher ACE inhibitory activities with58.36%.Salt was removed by ion exchange resin at a flow rate of10column volume/hour with desalinization rate of approximate and nitrogen recovery rate over80%.The ACE inhibitory activity was higher than before.Hypertension animal model SHR was used to evaluate the antihypertensive effect of peptides,systolic blood perssure (SBP) of the animal were test by a tail cuff blood pressure analyzer.Result showed that a maximal decrease in the SBP in SHR6h after giving casein peptide produce (2400mg/KgBW),4h of giving Captopril.The SBP of groups (600mg/KgBW、1200mg/KgBW、2400mg/KgBW) were lower than the group of control after20days treatment. The study showed that the antinypertensive peptide could decrease in SBP,but no effect on body weight.