Abstract:
A method for providing a heat treated liquid product is provided. The method comprises the steps of heating a flow of liquid product; providing an ice slurry of sterile water being separated from said flow of liquid product; and combining said flow of liquid product with said ice slurry for cooling down the flow of liquid product.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a method and system for providing a heat treated liquid product. More particularly, the present invention relates to a method and a system of which the heat treatment is improving the quality of the final product. 
       BACKGROUND 
       [0002]    In modern liquid processing systems heat treatment is often desirable for making the final product stable during subsequent processing and storage. Such heat treatment is normally performed by heating the liquid product to an elevated temperature, which temperature is sufficient to at least prevent microbial growth in the liquid product, as well as keeping the liquid product at that particular temperature for a specific period of time before the liquid product is cooled. Examples of such heat treatment is pasteurization and sterilization. 
         [0003]    In liquid food processing it is a well known fact that excessive heat load on the food product should be avoided, since heat treatment of the food product may affect the food product negatively, e.g. by causing losses in vitamin and mineral content. Therefore it is of major importance to control the heating as well as the subsequent cooling of the food product during such heat treatment. 
         [0004]    For some applications, e.g. food processing systems involving high viscous liquid products, heating has a much faster response than cooling. Since liquid product degradation is a direct function of heat exposure in respect of temperature as well as time, it would be beneficial to provide a heat treatment method which improves the quality of the final liquid product by allowing improved control of the heat load. 
       SUMMARY 
       [0005]    It is, therefore, an object of the present invention to overcome or alleviate the above described problems. 
         [0006]    The basic idea is to provide a heat treatment method, in which a liquid product concentrate is heat treated; whereafter said liquid product is combined with a predetermined amount of sterile water ice slurry. That is, the final liquid product is a blend of liquid product concentrate and water, whereby there is no need for coolant media, such as coolant water, for cooling down the product. Since cooling is achieved by combing the heated liquid product concentrate with the ice slurry, a less complex system may be utilized. 
         [0007]    According to a first aspect of the invention a method for providing a heat treated liquid product is provided. The method comprises the steps of heating a flow of liquid product; providing an ice slurry of sterile water being separated from said flow of liquid product; and combining said flow of liquid product with said ice slurry for cooling down the flow of liquid product. 
         [0008]    The method may further comprise the step of keeping the flow of liquid product at an elevated temperature for a predetermined time before the step of combining said flow of liquid product with said ice slurry. Hence, it may be possible to control not only the temperature but also the time for which the liquid product is subjected to said temperature whereby the entire heat load may be used as a parameter for controlling the heat treatment. 
         [0009]    The method may further comprise the step of providing said flow of liquid product as a flow of a liquid product concentrate. This is advantageous in that the final product does not need to be concentrated since water content is increased during combination with the ice slurry. 
         [0010]    The step of combining said flow of liquid product with said ice slurry may be performed such that the ratio between the amount of liquid product and the amount of sterile water ice slurry is between 10:1 and 20:1. This ratio is proven to be highly advantageous since rapid cooling is achieved without increasing the viscosity of the liquid product too much. Hence, standard heating devices may be utilized through which the liquid product will flow effectively. The temperature of the mix of liquid product and sterile water ice slurry may be between 30 and 50° C. 
         [0011]    The step of providing said sterile water ice slurry may be performed by the steps of pumping water through a sterile filter, and transporting said sterile water through a hygienic freezing cylinder. This is advantageous in that standard equipment is used for sterilizing and cooling the water in an efficient and cost effective way. 
         [0012]    Alternatively, the step of providing said sterile water ice slurry may be performed by the steps of sterilize water by heating, and transporting said sterile water through a hygienic freezing cylinder. 
         [0013]    The liquid product may be a liquid food product, such as a low acid beverage or similar. 
         [0014]    According to a second aspect, a combiner is provided. The combiner comprises a first inlet for receiving a heated liquid product, a second inlet for receiving a sterile water ice slurry, a combining chamber for cooling down said heated concentrate by combining said heated liquid product with said sterile water ice slurry, thereby also forming a heat treated liquid product, and an outlet for outputting said heat treated liquid product. 
         [0015]    The combiner may further comprise a controller configured to control operating parameters of the combiner such that said operating parameters may be adjusted in accordance with predetermined parameters for the specific liquid product. 
         [0016]    According to a third aspect, a system for providing a heat treated liquid product is provided. The system comprises at least one heater for increasing the temperature of a liquid product flowing through said heater, a supply of sterile water ice slurry, and a combiner according to the second aspect. 
         [0017]    According to a fourth aspect, a liquid food product is provided, wherein the product is manufactured by the method according to the first aspect. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0018]    The above, as well as additional objects, features, and advantages of the present invention, will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, wherein: 
           [0019]      FIG. 1  is a schematic view of a prior art system for heat treating a liquid product; 
           [0020]      FIG. 2  is a diagram showing the temperature of the liquid product flowing through the system of  FIG. 1 ; 
           [0021]      FIG. 3  is a schematic view of an embodiment of a system for heat treating a liquid product according to various methods; 
           [0022]      FIG. 4  is a diagram showing the temperature of the liquid product flowing through the system of  FIG. 3 ; 
           [0023]      FIGS. 5 a  and 5 b    are schematic views of different embodiments of a subsystem for providing an ice slurry; and 
           [0024]      FIG. 6  is a method scheme for a heat treating method according to an embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    Starting with  FIG. 1  a prior art heat treatment system  10  is shown. The system  10  includes a batch tank  11  enclosing a certain amount of liquid product to be heated. Upon heating, the liquid product is transported through a heat exchanger  12  wherein the temperature of the liquid product is elevated to a predetermined temperature for achieving the required heat treatment, such as pasteurization. The liquid product is thereafter kept at the elevated temperature during transportation through a holding cell  13  for ensuring the desired heat load to the liquid product. After heat treatment is completed, the liquid product is typically transported through a further heat exchanger  14  for cooling down the liquid product. 
         [0026]      FIG. 2  shows the temperature of the liquid product as it is transported through the system  10  of  FIG. 1 . As can be seen, a first heating zone corresponds to the liquid product passing through the heat exchanger  12 . Following that, the temperature is more or less constant as the liquid product is transported through the holding cell  13  before it is cooled down by the subsequent heat exchanger  14 . As is shown in  FIG. 2 , the temperature derivative is approximately the same during heating and cooling. 
         [0027]    Now turning to  FIG. 3  an embodiment of a liquid product system  100  is shown. The present system  100  is advantageous for a wide range of liquid products, such as liquid food, pharmaceuticals, cosmetics, etc for which temperature control is critical. As is shown in  FIG. 3  a liquid product supply  110  is provided. The liquid product supply  110  may e.g. be a batch tank, or e.g. upstream liquid product processing equipment capable of supplying a flow of liquid product. 
         [0028]    Preferably, the liquid product entering the system  100  is a concentrate, whereby at least a part of the water content required for the final product is reduced to a level below the desired water content of the final liquid product. The liquid product, or liquid product concentrate is transported through a heating device  120  for increasing the temperature of the liquid product, or liquid product concentrate up to a level sufficient to prevent the growth of micro organisms, e.g. up to a pasteurization temperature or a sterilization temperature. 
         [0029]    Preferably, the heat treatment device  120  includes a heat exchanger  122  and a holding cell  124  arranged in series such that the elevated temperature may be maintained for a predetermined time. The heat exchanger  122  and the holding cell  124  may be provided as one single device. Further, the heat exchanger  122  may be replaced by other heating devices, such as an ohmic heater or a microwave heater or other heating devices with a fast response. 
         [0030]    The heating device  120  may preferably be configured for a high viscous liquid product concentrate, such as a juice concentrate or similar high acid liquid product concentrate. In case of fruit juice concentrate, the viscosity may be in the range of 2500-3500 cpa. Correspondingly, for such juice concentrate the desired heat treatment temperature may e.g. be 90-95° C., while the holding cell  124  is configured to maintain the elevated temperature for approximately 15 seconds. 
         [0031]    The heated liquid product is pumped into a combiner  130 , which combiner  130  serves to increase the water content of the liquid product as well as reducing the temperature of the liquid product. For this, the combiner  130  receives the flow of liquid product as well as a sterile water ice slurry via a sterile water ice slurry supply  200  via two inlets. As the temperature of the ice slurry is far lower than the temperature of the liquid product, the temperature of the combined liquid product will rapidly decrease. Hence, rapid cooling is achieved. 
         [0032]    Preferably, the amount of liquid product entering the combiner  130  may be in the range of 90-95% of the combined product, such that the ratio between the amount of liquid product entering the combiner  130  and the amount of sterile water ice slurry entering the combiner  130  is between 10:1 and 20:1. Such ratio may provide a rapid cooling of the liquid product from 90° C. down to 30-50° C. by the introduction of the sterile water ice slurry. 
         [0033]    After passing through the combiner  130 , the combination of liquid product and water may pass through a subsequent cooler for a further reduction of temperature of the liquid product before additional processing equipment  150 , such as homogenizers, separators, etc. In another embodiment, the combined liquid product could be transported to a filling machine, wherein the liquid product is stored in consumer packages. 
         [0034]    As is also shown in  FIG. 3 , a controller  160  is provided for implementing control schemes to various components of the system  100 . For example, the controller  160  is configured to control the operating parameters of the heat treatment device  120  such that the heating parameters (e.g. maximum temperature, temperature gradient, holding time, flow, pressure, etc) may be adjusted in accordance with required parameters for each specific liquid product. Further, the controller  160  may be configured to control the operating parameters of the sterile water ice slurry supply  200  such that associated parameters (e.g. flow, pressure, temperature, viscosity, etc) may be adjusted in accordance with required parameters for the liquid product to be mixed. As a further option, the controller  160  may be configured to control operating parameters of the combiner  130  such that the combiner parameters (e.g. speed, pressure, valve positions, etc) may be adjusted in accordance with required parameters for the combined liquid product. 
         [0035]    Now turning to  FIG. 4 , a diagram presenting the temperature curve of the liquid product is shown. Starting at the left end of the diagram, the incoming liquid product, or liquid product concentrate, has a constant temperature. This part of the diagram thus represents the temperature of the liquid product stored in the liquid product supply  110  of  FIG. 3 . As the liquid product is heated by heat treatment device  120 , the temperature is gradually increasing until a desired maximum temperature is reached. The temperature is kept substantially constant for a period of time, until the liquid product is mixed with the sterile water ice slurry. The temperature will then rapidly decrease due to the combining with ice slurry; whereafter the subsequent cooler  140  will reduce the temperature even further, however at a considerably lower rate. Hence, combining will ice slurry will provide a much more rapid cooling and thus allows more accurate controlling of the temperature of the liquid product as well as a significantly lower heat load. 
         [0036]    Now turning to  FIGS. 5 a  and 5 b   , different embodiments of the sterile water ice slurry supply  200  are shown. Starting with  FIG. 5 a   , non-sterile water is pumped through a sterile filter  210  and then passes through a freezing cylinder  220  for providing a mass of ice slurry before the combiner  130 . 
         [0037]    Another embodiment, shown in  FIG. 5 b   , includes a heat treatment device  215  for replacing the sterile filter  210  of  FIG. 5 a   . The heat treatment device  215  may be any suitable heater, e.g. an UHT system such as the Tetra Plex®, currently available on the market. 
         [0038]    Now turning to  FIG. 6 , embodiments of a method  300  will be described. Starting at step  302 , a liquid product is provided. The liquid product may be e.g. a liquid food product, such as high acid beverage concentrate. In step  304 , the liquid product is fed to a heat treatment device, whereby heating of the liquid product is provided during step  306 . Optionally, the liquid product is transported through a holding cell during a subsequent step  308 . In step  310  a sterile water ice slurry is provided. Step  310  may preferably be performed in parallel with steps  302 ,  304 ,  306 , and  308 . 
         [0039]    The sterile water ice slurry is combined with the liquid product in step  312 , whereby the temperature of the liquid product is rapidly decreased. An optional step  314  may be performed for further cooling of the liquid product. 
         [0040]    Although the above description has been made mostly with reference to a liquid food processing system, it should be readily understood that the general principle of the combiner is applicable for various different liquid processing systems. 
         [0041]    Further, the invention has mainly been described with reference to a few embodiments. However, as is readily understood by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended claims.