Abstract:
The color level in milkfat is reduced by heating milkfat to 200 degrees C. and 300 degrees C. for a period of less than tern minutes, preferably using an intimate thermal contact between the heater and the milkfat. The heater may in one embodiment have a heated inner core which may include a plurality of longitudinal or spiral or other grooves of channels on its outer surface to provide elongate flow paths for the milkfat.

Description:
BACKGROUND OF INVENTION 
     The present invention relates to improvements in and relating to processes and/or apparatus for the treatment of milkfat. More particularly the present invention relates to processes and/or apparatus for the reduction of carotene and colour levels in milkfat. 
     To the present time the use of milkfat for some food products has needed to overcome the inherent problem that standard milkfat is yellow due to its colouring by carotene. 
     In order to bleach milkfat to make it suitable for use in food products, where the yellow colour would be unacceptable, typically processing equipment used for decolourising vegetable oil has been leased or hired out. This, however, has proved a very expensive operation in that such oil decolourisers are very expensive to run involving a lengthy process time for the milkfat. Typically utilising oil decolourisation equipment, the milkfat may have to be processed for up to eight hours. A further difficulty is that such oil decolourisation plants are typically, at least in New Zealand, geographically remote from the milkfat supply, involving the need to transport the milkfat to and from the decolourisation plant. 
     OBJECTS OF THE INVENTION 
     It is thus an object of the present invention to provide a process and/or apparatus for the decolourisation of milkfat, which term including gradations of colour removal, from the reduction of colour to a substantial total removal or bleaching of the milkfat, and in a relatively simple and cost effective way, and which will avoid or at least obviate problems in such processes/apparatus to the present time or which at least will provide the public with a useful choice. 
     Further objects of this invention, which should be considered in all its novel aspects, will become apparent from the following description, 
     BRIEF SUMMARY OF THE INVENTION 
     According to one aspect of the present invention a process for the reduction of the colour level in milkfat comprises: 
     (i) Providing a heating means adapted to enable a flow therethrough of a quantity of milkfat; 
     (ii) Controlling said flow of milkfat through said heating means and/or controlling the temperature of said heating means whereby the temperature of said milkfat as it passes through said heating means is between substantially 200° C. and 300° C. for a time sufficient to reduce the colour of said milkfat by a required amount. 
     According to a further aspect of the present invention there is provided apparatus for the reduction of the colour level in milkfat comprising: 
     (i) A heating means adapted to allow a flow therethrough of a quantity of milkfat; 
     (ii) Flow control and/or temperature control means provided for or associated with said heating means whereby said quantity of milkfat as it passes through said heating means is raised to a temperature of substantially between 200° C. and 300° C. for a time sufficient to decolour the quantity of milkfat by a required amount. 
     In one possible embodiment of the invention said heating means as defined in either of the two immediately above paragraphs may include a plurality of longitudinal or spiral grooves or channels through which said quantity of milkfat is caused to travel as it is heated. 
     In one possible embodiment of the invention said heating means of any of the three immediately above paragraphs may provide a required pressure or partial vacuum on said quantity of milkfat. 
     Possibly in one embodiment a vapour release may be provided to atmosphere or partial vacuum. 
     In one possible embodiment of the invention said milkfat may be de-aerated before it is entered into said heating means. 
     In one possible embodiment of the invention said milkfat may have vapour or gas introduced before or after it is entered into said heating means. 
     Possibly the apparatus and/or process for the decolourisation of milkfat is substantially as herein described with reference to the accompanying drawings. 
     Further aspects of this invention which should be considered in all its novel aspects will become apparent from the following description given by way of example of possible embodiments thereof and in which reference is made to the accompanying drawings, 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG.  1 : Shows diagrammatically one possible apparatus/process for the decolourisation of milkfat according to one possible embodiment of the invention; 
     FIG.  2 : Shows diagrammatically a cross-sectional view through a heating means according to one possible embodiment of the invention; 
     FIGS.  3 ( a ),( b ) Show diagrammatically inside and cross sectional views respectively, of an inner core for use in the heating means of FIG. 2; 
     FIG.  4 : Shows diagrammatically an enlarged view of the area B of FIG.  3 ( b ); and 
     FIG.  5 : Very diagrammatically provides a flow chart for possible process options according to possible embodiments of the present invention. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     To the present time the decolourisation of milkfat has involved utilizing equipment designed for use in respect of another food product, namely edible oil. This has resulted, as mentioned above, in considerable costs and process times being involved. 
     Typically a process time for the decolourisation of milkfat using such equipment could be of the order of 8 hours. 
     The present applicant has however found that by increasing the process temperature and ensuring the efficient heating of the milkfat, a shorter process time, possibly of less than 10 minutes, can result in an acceptable decolourisation of the milkfat. 
     The present invention, as will now be described, therefore provides a high temperature, short time, process whereby the carotene in milkfat, which results in the yellow colour, can be broken down and the milkfat thereby decoloured. 
     Referring to FIG. 1 a possible process flow path is shown with the milkfat being introduced into the process line in a direction indicated by arrow A into a de-aerator  21  and then through a heat exchanger  22  to a heating means  23  which will be described hereinafter in greater detail in one possible embodiment. 
     The heating of the milkfat in the heating means  23  is at a sufficiently high temperature and held for a sufficient time that the end product exiting in a direction indicated by arrow B has a colour which has been reduced to a sufficient degree with the breaking down of the carotene which has occurred. 
     The heating means  23  may be of any suitable type. However, the applicant has found that a heating means  23  where a substantially intimate contact between the milkfat and the heat source is provided, can achieve a beneficial effect. The integers identified as “P” or “T” in the FIG. 1 are typically respective pressure and temperature monitoring and/or control means. 
     In the type of heating means  23  illustrated in FIG. 2 an inner core  24  provides for the flow of the milkfat in a direction indicated by the arrows X through the heating means  23 . The inner core  24  is electrically conductive and is magnetically linked with external transformer windings  25  so that the core  24  is heated by the currents induced in it and thereby heats the milkfat passing over the inner core  24 . It is emphasised that this type of electrically powered heater is but one example of a heating means which may he suitable for use with the present invention. 
     As mentioned previously, it is important that an intimate relationship is created between the heating means  23  and the milkfat flowing through it. 
     Referring therefore to FIG. 3, the inner core  24  is shown as including an elongate outer surface. 
     In FIG. 4 a very enlarged view is shown of the area referenced by arrow B in FIG.  3 ( b ). The peripheral edge or circumference defining the outer surface of the core  24  is shown including a plurality of longitudinal or spiral or other grooves or channels  25  each of which can thereby define elongate flow paths for the milkfat. In this way the milkfat is provided with an intimate thermal contact with the inner core surface to ensure efficient heating of the milkfat as it passes through the heating means  23 . The number, size and shape of the grooves or channels  25  may vary depending on the rate of flow of the milkfat through the heating means  23  which is desired to be achieved and inherently the temperature which is being reached within the heating means  23 . 
     In FIG. 5 possible flow paths are indicated for the possible processes of the present invention. It is seen that the starting material may be provided as anhydrous milkfat or hydrated milkfat with possibly less than 10% water. The starting material is then indicated as possibly being de-aerated and/or other oxidation controls being imposed. 
     The milk fat is then shown in these examples as being heated to more than 200° C. for less than 10 minutes either under pressure or under partial vacuum. 
     It is then seen that in one potential flow path there may be a vapour release to atmosphere or partial vacuum followed by cooling and a possible alkaline refining followed by possible deodorising and the possible addition of antioxidants. In the other flow path, after heating, the milk fat is seen to possibly be deodorised and/or steam stripped under vacuum prior to the possible addition of antioxidants. 
     It is seen that in both these possible flow paths a high temperature, above 200° C., is applied to the milk fat for a relatively short period indicated as being less than 10 minutes. In either case in these examples the resultant milk fat has been decolourised to a sufficient extent. 
     The applicant has found that using a temperature in the range of between 200° C. and 300° C., a heating time of less than 10 minutes and an electrically generated and controlled heat source rather then a hot air, gas or vapour source or indirect heat source i.e. one with an intermediate thermal transfer medium, provides for an especially effective decolourisation. 
     Where in the foregoing description reference has been made to specific components or integers of the invention having known equivalents then such equivalents are herein incorporated as if individually set forth. 
     Although this invention has been described by way of example and with reference to possible embodiments thereof it is to be understood that modifications or improvements may be made thereto without departing from the scope or spirit of the invention as defined in the appended claims.