Selectivity aspects of lipolysis of milkfat (butteroil) by immobilized pregastric esterases from kid goats and lambs

• Published in: Journal of food science Vol. 71; no. 2; pp. E68 - E79
• Main Authors: Hill, C.G. Jr, Ghannouchi, S, Lopez-Hernandez, A, Garcia, H.S
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-03-2006; Institute of Food Technologists; Wiley Subscription Services, Inc
• Subjects: acylation; anhydrous milkfat; Animal productions; Biological and medical sciences; butter oil; deacylation; enzymatic hydrolysis; enzyme kinetics; Enzymes; esterases; Fatty acids; Food industries; Food science; Fundamental and applied biological sciences. Psychology; Goats; hollow-fiber reactor; immobilized enzymes; immobilized lipase; kids; lambs; lipolysis; lipolyzed butteroil; mathematical models; mechanism of action; Milk; milk fat; Oils & fats; optimization; pregastric esterase; Regression analysis; salivary glands; selective release of fatty acid residues; Sheep; temperature; Terrestrial animal productions; Vertebrates; Immobilization; Triacylglycerol lipase; Lipids; Esterases; Selectivity; Lamb; Meat animals; Hollow fiber; Goat; Reactor; Ungulata; Release; Dairy animal; Farming animal; pregastric esterase; selective release of fatty acid residues; Enzyme; Fatty acids; Lipolysis; Carboxylic ester hydrolases; Vertebrata; Mammalia; Residue; Hydrolases; Sheep; hollow-fiber reactor; Artiodactyla; anhydrous milkfat; immobilized lipase; lipolyzed butteroil
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/j.1365-2621.2006.tb08899.x

Pregastric esterases derived from the salivary tissues of kid goats and lambs were immobilized by physical adsorption in a continuous flow, hollow-fiber reactor and subsequently used to hydrolyze anhydrous milkfat, thereby producing lipolyzed butteroils. These 2 esterases were used in separate trials conducted at temperatures of 40 degrees C, 45 degrees C, and 50 degrees C and pH values of 5.0, 6.0, and 7.0. High-performance liquid chromatography (HPLC) was used to determine the relative proportions of the different fatty acid residues released as functions of the reactor space time for the indicated operating conditions. For both esterases, the rates of the lipolysis reactions were fastest at 40 degrees C and a pH of 6.0. The rates of release of the native individual fatty acid residues were modeled using expressions of the generalized Michaelis-Menten form based on a ping pong bi bi mechanism. Nonlinear regression analyses indicated that for both esterases, the experimental data were consistent with the form of the ping pong bi bi mechanism for which the rate controlling step is deacylation of the enzyme.