Patent Publication Number: US-6991819-B2

Title: Food product containing instable additives

Description:
The invention relates to a food product containing instable additives, having a food compound consisting of a porous matrix provided with a substrate containing instable additives. 
     U.S. Pat. No. 5,968,569 discloses a food product which contains probiotic microorganisms, in which either a substrate containing probiotic microorganisms is sprayed onto a matrix or alternatively a cavity within the matrix is filled with the substrate. 
     The problem of the invention consists in providing a food product obtained by a method by which it is possible to achieve an improved metering and more even distribution of the substrate containing instable additives on the matrix, and by which improved encapsulation and a longer active life of the probiotic microorganisms within the food product is ensured. 
     This problem is solved, in accordance with the present invention by a food product containing instable additives, having a food compound consisting of a porous matrix which is provided with a substrate containing instable additives, obtainable by a process in which, in a first step, the matrix is exposed to a partial vacuum; in a second step, the substrate containing instable additives is applied, in a flowable form, to the matrix under the partial vacuum; and in a third step, the pressure is increased, so that the substrate is forced into the pores of the porous matrix and substantially fills them out. 
     The substrate can contain probiotic microorganisms. 
     The substrate can contain bioactive substances, in particular enzymes. 
     Preferably, the substrate contains curcumin. 
     The substrate can contain perna canaliculus (New Zealand Green-Lipped Mussle) or extracts therefrom. 
     Furthermore, the substrate can contain L-glutamine, vitamins and/or flavourings. 
     Preferably, the substrate contains pharmaceutical agents. 
     The substrate can contain substances that are sensitive to water and/or air. 
     Preferably, the matrix is an extrudate. 
     The matrix can be an extrudate and may contain corn and/or rice, for example. 
     The substrate can contain fat, oil or some other liquid. 
     Preferably, the food product has an air-tight encapsulation made of a coating material, wherein the coating material can contain fat, it can contain flavourings and can consist at least partially of chocolate. 
     More preferably, it is envisaged that any pores or pore regions not filled with substrate are at least partially filled with an inert gas, especially nitrogen or carbon dioxide. 
     The substrate can contain Bacillus lichniformis and/or Bacillus subtilis and/or Lactobacillus acidophilus La5. 
     The partial vacuum can be between 40 mbar and 990 mbar, especially 200 mbar. 
     It can be provided for the pressure to which the matrix is exposed in the first step to be reduced within a transition period, beginning at atmospheric pressure, down to the partial vacuum. 
     In addition, it can be provided for the pressure to be increased, in the third step, to above atmospheric pressure. 
     Preferably, it is provided for the pressure to be increased by means of an inert gas, especially nitrogen or carbon dioxide. 
     At the beginning of the first step, the matrix can be at a temperature which is in the region of or below the boiling temperature of water corresponding to the partial vacuum. 
     As a further embodiment of the invention, it can be provided for the matrix to be extruded and for the first step to be carried out immediately after that, so that the matrix is further expanded and is dried and simultaneously cooled within the first step. 
     It can be provided for the matrix, at the beginning of the first step to be at a temperature of more than 90° C. 
     In addition, it can be provided for the matrix to be predried before the first step. 
     If the matrix is predried within the first step, it can be provided for the partial vacuum to be maintained until the matrix has reached a temperature of 30° C. or less. 
     During the first step, additional energy, especially in the form of infrared or microwave radiation, can be applied. 
    
    
     
       Further advantages and features of the invention can be seen from the following description of preferred embodiments, reference being made to drawings in which 
         FIG. 1  shows an example of the development, over time, of the product temperature and pressure during the preparation of the food product of the invention, 
         FIG. 2  shows an example of a configuration for carrying out the process explained in  FIG. 1 , and 
         FIG. 3  is a similar presentation to  FIG. 1 , showing the development, over time, of the product temperature and pressure in an alternative process for preparing the food product. 
     
    
    
     In order to explain the preparation process, reference is first made to  FIGS. 2 and 3 . A mixture to be extruded, consisting of different food ingredients, enters the extruder  1  (arrow  2 ) and emerges from it at the exit orifice  3  at a temperature of approx. 100° C. The extruded product, which forms the porous matrix or basic matrix for the substrate to be applied later, is dried in a drier  4  and subsequently provided with a substrate in a mixer  5 . 
       FIG. 3  serves to explain the time sequence of the processes in the course of vacuum coating inside the mixer  5 . Extruded, dried, porous matrix material cooled to approx. 30° C. is introduced at ambient pressure in the form of individual food compounds (“kibbles”) into the mixer  5  with its charging door facing upwards (left-hand drawing in  FIG. 2 ). The opening of the hopper is closed, and the internal pressure is reduced, within a relatively short time, e.g. about 1.5 minutes, to a predetermined partial vacuum. The level of this partial vacuum ought to be as low as possible, e.g. down to 40 mbar or also 200 mbar, and is orientated not only towards the general technical conditions, but also towards the kind of probiotic microorganisms contained in the substrate to be introduced and how sensitive they are to reduced pressure, so that, as far as possible, no harm is done to the microorganisms. 
     Before, after or simultaneously with the introduction of the matrix, the substrate is introduced into the mixer, e.g. by spraying, and the matrix is mixed with said substrate. Ideally, as even as possible a layer forms in the process, consisting of flowable substrate on the outer surface of the individual food compounds in the matrix. 
     Following this, the pressure in the mixer is raised back to ambient pressure (or briefly even higher), in the course of which the coating material is forced deep into the porous cavities of the extruded matrix. In order to insulate the probiotic microorganisms as far as possible and to shield them from atmospheric oxygen and other influences, this pressure increase can be achieved by means of an inert gas, e.g. nitrogen or carbon dioxide, which penetrates into the pores and fills out the pores or pore regions not filled with substrate. As an alternative, the complete method performed in the mixer can be carried out closed off from air, e.g. in an atmosphere of protecting gas, so that the substrate does not come into contact with air at any time. 
     Throughout the entire procedure, the product temperature remains virtually unchanged at approx. 30° C., which corresponds to the temperature at which the matrix is introduced. In order to enhance the flowability and the penetration effect, the substrate can be at a slightly higher temperature, e.g. 50° C. 
     Alternatively it is possible to arrange the process in accordance with  FIG. 1 . Here, the extruded porous matrix, which exits from the extruder  1  at approx. 100° C., is initially not cooled, and is introduced into the mixer  5  at approx. 95° C. At this point, it should also be pointed out that, in  FIGS. 1 and 3 , the boiling point of water is plotted on the right-hand side which corresponds in each case to the pressure shown on the left. 200 mbar thus corresponds to a boiling point of approx. 60° C., 40 mbar to approx. 30° C. etc. 
     After the mixer is closed, the pressure is reduced to approx. 200 mbar or even further, e.g. to 40 mbar ( FIG. 1 ), so that, because of the reduction in the boiling point and the accompanying evaporation of part of the water contained in the extruded material, this can lead to a (further) swelling and considerable cooling and drying. After the pressure of the desired partial vacuum of, for example, 40 mbar or 200 mbar has been achieved and, where appropriate, maintained at that level for a certain time, the desired cooling and drying has occurred, e.g. after cooling to 30° C. (boiling point at 40 mbar). 
     After this, the substrate containing microorganisms is applied to the food compound present in the mixer. 
     In other respects, the approach corresponds to the process described in connection with  FIG. 3 . Since, when vacuum drying of this kind is effected simultaneously with or immediately prior to application to the substrate, only minor local fluctuations in the moisture content occur, this leads to a very accurate adjustment to the moisture, so that the average moisture content compared to hot-air drying can be raised by approx. 1% by weight. This results in considerable energy savings. 
     Irrespective of the process arrangement selected, the food compounds are subsequently coated with a coating material. 
     The benefits obtained with the invention consist firstly in the fact that the probiotic microorganisms are sealed in the pores of a porous matrix and are shielded from environmental influences (atmospheric oxygen etc.). In this way, the active life of the microorganisms is substantially longer than when they are applied to the surface. 
     Furthermore, the achievable metering accuracy compared to conventional techniques is considerably better, so that a food product can be loaded far more evenly with probiotic microorganisms. 
     A further advantage of the invention is that both during the preparation of and while handling the finished products, there is a substantially reduced likelihood that probiotic microorganisms are unintentionally transferred, since the microorganisms are essentially located inside the product, in the pores of the matrix. 
     The invention creates the possibility of enhancing not only animal feed, but also snack products for human consumption, such as corn or rice products, with probiotic microorganisms, whose positive effects on health are known.