title: Effect of power ultrasound pretreatment on peptidic profiles and angiotensin converting enzyme inhibition of milk protein concentrate hydrolysates.
abstract: BACKGROUND
  The use of power ultrasound as a pretreatment to enhance the hydrolysis of milk protein concentrate (MPC) and subsequent angiotensin converting enzyme (ACE) inhibitory activity has been studied. Liquid chromatography was used to analyse peptide profiles of Neutrase-derived MPC hydrolysates after pretreatment at 0, 1, 3, 5 and 8 min at an ultrasound power level of 800 W.
  
  
  RESULTS
  The peptide profiles indicated an increase in number of peptides when ultrasound pretreatment was applied. There was also an increase in the degree of hydrolysis of MPC hydrolysates. The profiles indicated that new small peptides in ultrasound pretreated samples (1-5 min) which were not present in the control samples and 8 min pretreated samples, could be responsible for increased ACE inhibitory activity. These small peptides were digested in the 8 min pretreated samples.
  
  
  CONCLUSIONS
  Ultrasound pretreatment of MPC increases the ACE inhibitory activity of the hydrolysates because of the production of new small peptides. This can be used as a means to derive potent ACE inhibitory peptides at industrial scale in complex protein sources.
authors.affiliation: Institute of Agro-Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, 100193, P.R. China; Faculty of Agriculture, Agricultural Engineering Department, Bunda College of Agriculture, Lilongwe, Malawi.
authors.forename: Hankie
authors.initials: H
authors.lastname: Uluko
authors.forename: Lu
authors.initials: L
authors.lastname: Liu
authors.forename: Hongjuan
authors.initials: H
authors.lastname: Li
authors.forename: Wenming
authors.initials: W
authors.lastname: Cui
authors.forename: Shuwen
authors.initials: S
authors.lastname: Zhang
authors.forename: Lili
authors.initials: L
authors.lastname: Zhao
authors.forename: Haixiao
authors.initials: H
authors.lastname: Xue
authors.forename: Jiaping
authors.initials: J
authors.lastname: Lv
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D006868:Hydrolysis; D008666:Metalloendopeptidases / Q000378:metabolism; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D010455:Peptides / Q000378:metabolism* / Q000494:pharmacology; D011492:Protein Hydrolysates / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D008894:Milk Proteins; D010446:Peptide Fragments; D010455:Peptides; D011492:Protein Hydrolysates; D010447:Peptide Hydrolases; D008666:Metalloendopeptidases; C044194:microbial metalloproteinases
keywords: angiotensin converting enzyme; hydrolysis; milk protein concentrate; ultrasound