title: Ultrasound-assisted generation of ACE-inhibitory peptides from casein hydrolyzed with nanoencapsulated protease.
abstract: BACKGROUND
  Bioactive peptides generated from milk proteins are eminent ingredients for functional foods and nutraceuticals. Amongst several approaches to release these peptides, hydrolysis of milk proteins with proteolytic enzymes is a promising choice. It is, however, required to inactivate the enzyme after a predetermined time, which leads to impurity of the final product. Immobilization of enzyme molecules can overcome this problem as it simplifies enzyme separation from the reaction mixture. A fungal protease from Aspergillus oryzea was encapsulated within nanoparticles yielded via silicification of polyamidoamine dendrimer template generation 0. It was used to hydrolyze the dominant milk protein (casein) in the absence or presence of sonication. The production of angiotensin converting enzyme (ACE)-inhibitory peptides was monitored during hydrolysis.
  
  
  RESULTS
  Sonication did not affect maximum ACE-inhibitory activity but shortened the process sixfold. Ultrafiltration permeate of the centrifugal supernatant of casein solution hydrolyzed during sonication inhibited ACE activity as efficiently as the supernatant obtained from it.
  
  
  CONCLUSIONS
  The protease from Aspergillus oryzea encapsulated within nanospheres is suitable for generation of ACE-inhibitory peptides from casein. The nanoncapsulation procedure is simple, rapid and efficient. This may enable the industrial production of functional products from milk.
authors.affiliation: Department of Food Science and Engineering, Faculty of Technology, Campus of Agriculture and Natural Resources, University of Tehran, Karaj, Iran. Ashkan.madadlou@gmail.com
authors.forename: Ashkan
authors.initials: A
authors.lastname: Madadlou
authors.forename: David
authors.initials: D
authors.lastname: Sheehan
authors.forename: Zahra
authors.initials: Z
authors.lastname: Emam-Djomeh
authors.forename: Mohammad E
authors.initials: ME
authors.lastname: Mousavi
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001236:Aspergillus oryzae / Q000201:enzymology; D040761:Biomimetic Materials / Q000737:chemistry; D002364:Caseins / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D010450:Endopeptidases / Q000378:metabolism*; D004800:Enzymes, Immobilized / Q000378:metabolism* / Q000528:radiation effects; D005656:Fungal Proteins / Q000378:metabolism / Q000528:radiation effects; D006868:Hydrolysis; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D010455:Peptides / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism; D011817:Rabbits; D013010:Sonication; D013678:Technology, Pharmaceutical; D014462:Ultrafiltration
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D002364:Caseins; D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D010446:Peptide Fragments; D010455:Peptides; C475729:casein hydrolysate; D010450:Endopeptidases; C412470:flavourzyme; D007703:Peptidyl-Dipeptidase A