Abstract: Thermal stability of microbial rennet is reduced by treatment of the rennet in aqueous medium with aliphatic or inorganic peroxy acids or salts thereof. Preferably, the microbial rennet is Mucor Miehei rennet and the peroxy acid is a lower aliphatic peroxy acid such as peracetic acid. The thermally destabilized microbial rennet is inactivated when whey containing the rennet is pasteurized.

Abstract: A stabilized solution of rennet; the stabilizing agent being methionine. The stabilizing agent is added in an amount corresponding to a concentration of between 0.1% (w/w) and saturation calculated on the total weight of the solution.

Abstract: Bacillus serine proteases are acylated with an acyl radical of a monocarboxylic or dicarboxylic acid of about 1 to 6 carbon atoms to thermally destabilize the proteases at least about 3.degree. C. The acylated proteases have at least about 50% of their activity before acylation, and are advantageous in processes where it is desired to inactivate the proteases at a certain point in the process.

Abstract: Microbial rennet such as from Mucor miehei is thermally destabilized by treatment of the rennet in an aqueous medium with oxidizing agents containing active chlorine such as hypochlorites. The thermally destabilized rennet is advantageous for cheese making where absence of rennet activity in pasteurized whey is desired.

Abstract: An immobilized enzyme granular product suitable for use in expanded and fluidized bed operations is formed by gelatine coating a dense particulate material, e.g., a mineral oxide, and hardening the coating with glutaraldehyde, then treating the coated particles with a pasty mixture of an enzyme substance and polyethylene imine, and thereafter treating the mixture with glutaraldehyde, followed by granulating and drying. Sand and titanium dioxide are preferred particulate materials. Lactase, urease, and inulinase are preferred enzymes, preferably in the form of whole or homogenized microbial cells.

Abstract: Microbial rennet having reduced thermal stability is produced by acylating the rennet with a monocarboxylic acid acyl radial of between 1 and 6 carbon atoms. Making cheese with the microbial rennet having reduced thermal stability enables the production of pasteurized whey having no residual rennet activity for use in human foods.