The method comprises contacting an animal product with a weak base having a pKa of 8-13 to form a mixture, and heating the mixture to a temperature of less than 121[deg] C, where the pH of the mixture after the heating step is 8.5-13, preferably 9-11. The amount of the weak base brought into contact with the animal product is less than 100 mmol.L->；1>；. The mixture is incubated at less than 50[deg] C for 10 minutes before the heating step. The heating step is carried out by wet heating. The heating step is carried out for 1-30 minutes. The method comprises contacting an animal product with a weak base having a pKa of 8-13 to form a mixture, and heating the mixture to a temperature of less than 121[deg] C, where the pH of the mixture after the heating step is 8.5-13, preferably 9-11. The amount of the weak base brought into contact with the animal product is less than 100 mmol.L->；1>；. The mixture is incubated at less than 50[deg] C for 10 minutes before the heating step. The heating step is carried out by wet heating. The heating step is carried out for 1-30 minutes. The heating step is followed by additional heating step of the mixture at a temperature of >；= 121[deg] C. The animal product is milled to an average particle size of less than 100 mm prior to the contacting step. A fat animal product is extracted prior to the contacting step.
