Method for Producing a Dairy Product

Abstract

The present invention relates to a method for producing a dairy product using an enzyme having lactase activity.

1 - 24 . (canceled) 
     
     
         25 . A method for producing a dairy product comprising
 a) providing a milk-based substrate comprising lactose; and   b) treating said substrate with an enzyme having lactase activity and selected from the group consisting of: an amino acid sequence which is at least 70% identical to amino acids 28-1331 of SEQ ID NO: 2 or a fragment thereof; an amino acid sequence which is at least 70% identical to amino acids 28-1931 of SEQ ID NO: 1 or a fragment thereof; an amino acid sequence which is at least 70% identical to any of SEQ ID NO's: 3-4 or a fragment thereof; and an amino acid sequence which is at least 70% identical to any of SEQ ID NO's: 5-7 or a fragment thereof.   
     
     
         26 . The method of  claim 25 , wherein the enzyme is derived from a microorganism of the genus Bifidobacterium. 
     
     
         27 . The method of  claim 25 , where the pH optimum of the lactase activity at 37° C. is above pH 5, and where the lactase activity of the enzyme at pH 5 is at least 50% of its lactase activity at pH 6 when measured at 37° C. 
     
     
         28 . A method for producing a dairy product comprising
 a) providing a milk-based substrate comprising lactose, and   b) treating said substrate with an enzyme having lactase activity, where the pH optimum of the lactase activity at 37° C. is above pH 5, and where the lactase activity of the enzyme at pH 5 is at least 50% of its lactase activity at pH 6 when measured at 37° C.   
     
     
         29 . The method of  claim 28 , wherein step b) takes place at a temperature of at least 50° C. 
     
     
         30 . A method for producing a dairy product comprising
 a) providing a milk-based substrate comprising lactose, and   b) treating said substrate with an enzyme having lactase activity,   wherein step b) takes place at a temperature of at least 50° C.   
     
     
         31 . The method of  claim 30 , wherein the lactase activity of the enzyme at a temperature of 52° C. is at least 70% of its lactase activity at a temperature of 38° C. when measured at pH 6.5. 
     
     
         32 . The method  claim 30 , wherein the enzyme is added to the milk-based substrate at a concentration of less than 30 LAU per g lactose in the milk-based substrate. 
     
     
         33 . The method of  claim 30 , wherein the enzyme is added to the milk-based substrate at a concentration of less than 1000 LAU per litre milk-based substrate. 
     
     
         34 . The method of  claim 30 , wherein the enzyme when hydrolysing the lactose in the milk-based substrate has a ratio of lactase to transgalactosylase activity of more than 1:1. 
     
     
         35 . The method of any of  claim 30 , further comprising a step
 c) fermenting said substrate with a microorganism,   wherein the dairy product is a fermented dairy product.   
     
     
         36 . The method of  claim 35 , wherein the fermented dairy product is yoghurt. 
     
     
         37 . The method of  claim 35 , wherein step b) and step c) are performed essentially at the same time. 
     
     
         38 . The method of  claim 35 , wherein the enzyme of step b) and the microorganism of step c) are added to the milk-based substrate at essentially the same time. 
     
     
         39 . The method of  claim 35 , wherein less than 80% of the lactose has been hydrolyzed after two hours of fermentation, and wherein more than 90% of the lactose has been hydrolyzed in the final fermented dairy product. 
     
     
         40 . The method of  claim 35 , wherein less than 80% of the lactose has been hydrolyzed when step c) is completed, and wherein more than 90% of the lactose has been hydrolyzed in the final fermented dairy product. 
     
     
         41 . The method of  claim 28 , wherein the milk-based substrate is raw milk which is not pasteurized before step b). 
     
     
         42 . The method of  claim 41 , wherein step b) is performed for between 10 minutes and 4 hours at a temperature of between 62° C. and 64° C., and wherein step b) is followed by cooling to below 10° C. without further heat treatment. 
     
     
         43 . The method of  claim 41 , wherein less than 80% of the lactose has been hydrolyzed when step b) is completed, and wherein more than 90% of the lactose has been hydrolyzed after one week. 
     
     
         44 . The method of  claim 41 , wherein step b) is performed for between 10 minutes and 4 hours at a temperature of between 62° C. and 64° C., and wherein step b) is followed by UHT treatment.