Preparation of cheese using ultrafiltration

A process for making a fat containing rennet coagulated cheese from milk, the cheese containing substantially all the casein and soluble proteins of the milk, wich comprises:

• separating the milk by ultrafiltration into a filtrate and a liquid retentate, by flowing the milk over semi-permeable membranes by introducing said milk into a plurality of porous tubes, each of said tubes being lined inside with a semi-permeable membrane, and wherein said filtrate is obtained by being passed through said membranes and said porous tubes, and is collected on the outer wall of said tubes, and said retentate inside the tubes becoming more concentrated in proteins as it passes through said tubes, the semipermeable membranes having an average pore diameter falling in the range which will permit water, lactose and soluble mineral salts contained in the milk to pass through the membrane as a filtrate up to 30 m.mu., the flow of the liquid within the tubes being sufficient to hinder film formation on the surface of said membranes which would prevent the flow of said water, lactose and soluble mineral salts passing through said membranes, said separation occurring at a pressure of 1 to 50 kg/cm.sup.2, and such that substantially all the casein and soluble proteins of said milk are retained in the liquid retentate;
• continuing said separation until a free flowing liquid retentate, collected separately from said filtrate, is obtained which has substantially the same total protein concentration and non-protein soluble constituents concentration as is known to exist in the milk derived components of a desired natural cheese at the end of the whey draining process, and thereafter adding sufficient rennet to said retentate to cause coagulation and cheese formation.

A process for making a fat containing rennet coagulated cheese from milk, the cheese containing substantially all the casein and soluble proteins of the milk, which comprises:

• separating the milk by ultrafiltration into a filtrate and a liquid retentate by flowing the milk over a first face of a semi-permeable membrane by introducing said milk into a module containing a porous plate, said porous plate serving as a frame for said semi-permeable membrane, and whereby said milk is separated into a filtrate which passes through the membrane and is collected in a space on the opposite face of said membrane and into retentate which recirculates through said module and becomes more concentrated in proteins as it recirculates, the semi-permeable membrane having an average pore diameter falling in the range which will permit water, lactose and soluble mineral salts contained in the milk to pass through the membrane as a filtrate up to 30 m.mu., the flow of the liquid over said first face of said semi-permeable membrane being sufficient to hinder film formation on the surface of said membrane which would prevent the flow of said water, lactose and soluble mineral salts passing through said membrane, said separation occurring at a pressure of 1 to 50 kg/cm.sup.2, and such that substantially all the casein and soluble proteins of said milk are retained in the liquid retentate;
• continuing said recirculation and separation until a free flowing liquid retentate, collected separately from said filtrate, is obtained which has substantially the same total protein concentration and non-protein soluble constituents concentration as is known to exist in the milk derived components of a desired natural cheese at the end of the whey draining process, and thereafter adding sufficient rennet to said retentate to cause coagulation and cheese formation.