title: Hydrolysis of a chitosan-induced milk aggregate by pepsin, trypsin and pancreatic lipase.
abstract: The addition of chitosan to whole milk results in dose dependent destabilization and coagulation of the casein micelles and milk fat. The present study evaluates how the presence of chitosan could affect the hydrolysis of this chitosan-induced aggregate by different gastrointestinal proteases (pepsin and trypsin) and by pancreatic lipase. The chitosan-milk aggregate was hydrolyzed by pepsin and trypsin, as evaluated by the UV absorbance of TCA-soluble peptides and by urea-PAGE. The kinetics and extent of hydrolysis were independent of the casein being soluble or aggregated. The release of soluble peptides from the aggregate was independent of the presence of chitosan. A progressive inhibition of pancreatic lipase was observed in proportion to the increase in molecular weight of the chitosan employed to induce the formation of the aggregate. Interestingly, the presence of chitosan not only affected the initial velocity of the reaction, but also reduced its extent. The results indicate that a milk aggregate induced by chitosan was very well digested by gastric and intestinal proteases independently of the molecular weight of the chitosan used, and that the aggregate could retain the lipid-lowering effect of chitosan.
authors.affiliation: Center of Excellence in Products and Processes of Cordoba, Cordoba Science Agency, Santa Maria de Punilla, Argentine.
authors.forename: S F
authors.initials: SF
authors.lastname: Ausar
authors.forename: C A
authors.initials: CA
authors.lastname: Landa
authors.forename: I D
authors.initials: ID
authors.lastname: Bianco
authors.forename: L F
authors.initials: LF
authors.lastname: Castagna
authors.forename: D M
authors.initials: DM
authors.lastname: Beltramo
mesh_terms: D000818:Animals; D002417:Cattle; D002686:Chitin / Q000031:analogs & derivatives; D048271:Chitosan; D004041:Dietary Fats / Q000032:analysis; D004063:Digestion; D005503:Food Additives; D006868:Hydrolysis; D066298:In Vitro Techniques; D008049:Lipase; D008892:Milk / Q000737:chemistry*; D010434:Pepsin A; D013552:Swine; D014280:Triglycerides / Q000737:chemistry; D014357:Trypsin
chemical_list: D004041:Dietary Fats; D005503:Food Additives; D014280:Triglycerides; D002686:Chitin; D048271:Chitosan; D008049:Lipase; D014357:Trypsin; D010434:Pepsin A