Process for making a shelf-stable milk based beverage concentrate

Abstract

A concentrate, system and low-temperature process for preparing a shelf-stable milk concentrate that does not require ultra-high temperature thermal processing for control of the microbiology of the product is disclosed herein. The method preferably incorporates aseptic technology and the enzymatic reduction of lactose to control water activity. The method preferably includes the enzymatic conversion of the lactose in the milk to its component sugars glucose and galactose, which preferably changes the colligative properties of the concentrate, decreases the amount of free water, and reduces the osmolarity.

I claim as my invention: 
     
         1 . A method for preparing a shelf-stable milk concentrate, the method comprising:
 concentrating milk using low temperature, vacuum evaporation to produce a milk concentrate;   adding a lactase enzyme and water to the milk concentrate to hydrolyze the milk concentrate into a concentrate of glucose and galactose; and   dissolving anhydrous sugar into the concentrate of glucose and galactose to form a shelf-stable milk concentrate e activity.   
     
     
         2 . A method for preparing a shelf-stable milk concentrate, the method comprising:
 adding a lactase enzyme and water to a milk concentrate to hydrolyze the milk concentrate into a hydrolyzed milk concentrate comprising glucose and galactose, the hydrolyzed milk concentrate having a minimal water activity.   
     
     
         3 . The method according to claim wherein a minimal water activity is less than 0.85. 
     
     
         4 . The method according to  claim 2  further comprising:
 adding a milk powder to the hydrolyzed milk concentrate to create a second milk concentrate having 4 times to 8 times concentration; 
 adding anhydrous sugar to the second milk concentrate with agitation and shearing to create first milk mixture, the anhydrous sugar added in an amount ranging from 1 to 50 weight percent of the first milk mixture; 
 heating the first milk mixture to a temperature ranging from 40° C. to 80° C.; 
 holding the first milk mixture until a water activity of the first milk mixture ranges from 0.8 to 0.9; 
 adding at least one additional ingredient to the held first milk mixture to create a second milk mixture; 
 thermally treating the second milk mixture to create a finished milk concentrate; and 
 packaging the finished milk concentrate. 
 
     
     
         5 . The method according to  claim 4  wherein the additional ingredient comprises at least one of stabilizers, salt and flavoring. 
     
     
         6 . The method according to  claim 4  wherein thermally treating the second milk mixture comprises heating the second milk mixture to a Pasteurization temperature ranging from 72° C. to 125° C. 
     
     
         7 . The method according to  claim 4  wherein the additional ingredient comprises at least one of stabilizers, salt and chocolate. 
     
     
         8 . The method according to  claim 2  further comprising:
 introducing a milk product into a balance tank; 
 heating the milk product in a holding tube at a temperature ranging from 170° F. to 240° F. to create a heated milk product; 
 introducing the heated milk product into a pre-sterilized vacuum chamber as a falling film to remove water from the heated milk product to create a condensed milk product; and 
 homogenizing the condensed milk product in an aseptic homogenizer to create the milk concentrate. 
 
     
     
         9 . The method according to  claim 2  further comprising:
 introducing a raw milk product into a balance tank; 
 heating the raw milk product in a preheater to create a preheated milk product; 
 injecting the preheated milk product into a first effect wherein the preheated milk product is heated at a temperature of about 70° C. to evaporate water and increase a solids content of the preheated milk product to create a first effect milk product with a solids concentration of from 10% to 13%; 
 injecting the first effect milk product into a second effect wherein the first effect milk product is heated at a temperature of about 65° C. to evaporate water and increase a solids content of the first effect milk product to create a second effect milk product with a solids concentration of from 13% to 18%; 
 injecting the second effect milk product into a third effect wherein the second effect milk product is heated at a temperature of about 62° C. to evaporate water and increase a solids content of the second effect milk product to create a third effect milk product with a solids concentration of from 18% to 27%; 
 injecting the third effect milk product into a fourth effect wherein the third effect milk product is heated at a temperature of about 60° C. to evaporate water and increase a solids content of the third effect milk product to create the milk concentrate with a solids concentration of from 28% to 34%; 
 injecting the milk concentrate into a fifth effect along with the a lactase enzyme, wherein the fifth effect is heated at a temperature of about 48° C. to evaporate water and increase a solids content to create hydrolyzed milk concentrate with a solid concentration of from 34% to 42%; 
 injecting the hydrolyzed milk concentrate into a sixth effect wherein the hydrolyzed milk concentrate is heated at a temperature of about 43° C. to evaporate water and increase a solids content of hydrolyzed milk concentrate to create a final hydrolyzed milk concentrate with a solids concentration of from 42% to 50%; 
 holding the final hydrolyzed milk concentrate in an aseptic tank at a temperature of about 80° F.; and 
 packaging the final hydrolyzed milk concentrate in an aseptic container using an aseptic filling machine. 
 
     
     
         10 . The method according to  claim 9  wherein the raw milk product is heated to a temperature of 100° C. for a time period ranging from 1 second to five minutes to inactive a plurality of microorganisms and a plurality of enzymes. 
     
     
         11 . The method according to  claim 2  further comprising reconstituting the hydrolyzed milk concentrate into a fresh-tasting product. 
     
     
         12 . The method according to  claim 2  further comprising minimizing a plurality of thermal reactions of the hydrolyzed milk concentrate by incorporating a plurality of dry ingredients at an end of the method and by chemically increasing the osmolality of the hydrolyzed milk concentrate using the lactase enzyme. 
     
     
         13 . A system for preparing a shelf-stable milk concentrate, the system comprising:
 a source of a milk product;   means for concentrating the milk product using low temperature, vacuum evaporation to produce a milk concentrate; and   means for adding a lactase enzyme and water to the milk concentrate to hydrolyze the milk concentrate into a hydrolyzed milk concentrate comprising glucose and galactose.   
     
     
         14 . The system according to  claim 13  further comprising means for dissolving anhydrous sugar into the hydrolyzed milk concentrate to form a shelf-stable milk concentrate with minimal water activity. 
     
     
         15 . The system according to  claim 13  wherein the means for concentrating the milk product comprises a plurality of effects. 
     
     
         16 . The system according to  claim 13  wherein the means for concentrating the milk product comprises an aseptic vacuum cooling vessel. 
     
     
         17 . The system according to  claim 16  wherein the means for concentrating the milk product further comprises an aseptic homogenizer. 
     
     
         18 . The system according to  claim 14  further comprising means for aseptically packaging the shelf-stable milk concentrate. 
     
     
         19 . The system according to  claim 14  wherein the shelf-stable milk concentrate has a water activity value lower than 0.85. 
     
     
         20 . The system according to  claim 13  wherein the hydrolyzed milk concentrate is from 70% to 99.5% hydrolyzed.