Method and relevant facility for the processing of an alimentary product with a liquid content

Abstract: A method and a relevant facility for the treatment of an alimentary product with a liquid content calls for a step in which the whole alimentary product is disintegrated and in which the disintegrated alimentary product is for the first time at such a temperature as to undergo an evaporation, and calls for subsequent steps of processing of the disintegrated alimentary product; the evaporate resulting from the evaporation is condensed and collected, with the flavouring substances contained in the evaporate being recovered.

Description: The object of the present invention is a method and a relevant facility for the processing of an alimentary product with a liquid content. Treatment routes for processing alimentary products with a liquid content, such as, e.g., vegetable products (fruit, vegetables, and so forth), in which the alimentary product is ground and is submitted to a heating in one or more step(s), with the partial evaporation being caused of the same product, are known in the art. The document US-A-3 959 067 discloses a method for the concentration of products like fruit juices, comprising evaporation and recovering the flavouring substances. The volatile constituents are recombined with the partially concentrated product before a final stage of the evaporation. For example, in the processing of whole tomato in order to obtain tomato concentrate, tomatoes, after being washed and sorted, are ground and pre-heated, from ground, pre-heated tomato seeds and peels are then removed, is then submitted to a series of heating steps with relevant evaporation, which cause it to be concentrated, and is then sent to the steps of pasteurization and packaging. Unfortunately, the heating step, or the series of heating steps of the alimentary product cause a depletion of the flavouring substances contained in the same product. In this way, the end alimentary product loses most of its content of flavouring substances, and therefore it loses one of its most important characteristics, with reference to its end destination of alimentary product to be tasted. It would certainly be desirable that the above said content of flavouring substances unavoidably lost or damaged during the transformation process the product is submitted to, was preserved. It is furthermore desirable that such a preservation be achieved at an optimum level. The purpose of the present invention is of fulfilling the above said requirements. Such a purpose is achieved by means of a method for the processing of an alimentary product with a liquid content as claimed in claim 1. In the following, an example of practical embodiment of a facility for carrying out the method according to the present invention is disclosed by referring to the hereto attached single drawing table which shows a general schematic view of said facility. The facility shown is destined in particular to the processing of tomato. The facility is provided with a feeding section, which comprises a hopper 10 and a deaerator 11 connected through a duct 12. The deaerator 11 is connected with a vacuum pump 13 through a duct 14. At the outlet ends of the hopper 10 and of the deaerator 11, two respective axial pumps 15 and 16 are installed. The facility is then provided with a heating/preconcentration section comprising an evaporation unit 17. The evaporation unit 17 comprises a heat exchanger 18 of tube-bundle type, and a vapour separator 19 (which substantially is a vessel inside which the separation of the liquid phase from the vapour phase takes place). The bottom side of the heat exchanger 18 is connected with the delivery end of recycle means, such as a centrifugal pump 20, the intake end of which is connected with a duct 21 which puts the pump 20 in communication with the bottom side of the vapour separator 19. A duct 22 puts then the top side of the heat exchanger 18 in communication with the vapour separator 19. The duct 21 communicates with the delivery end of the pump 16 through a duct 23. The heat exchanger 18 comprises in its interior a tube bundle 24; inside said tubes tomato flows. The interior of said tubes is connected at an end with the delivery end of the pump 20, and at its other end with the duct 22. The external side of the tubes of the tube bundle is destined to be lapped by steam coming from an external steam source schematically respresented by a block 25, connected with the heat exchanger 18 through a duct 26; by means of the reference numeral 9, the drain for the condensate steam from the heat exchanger 18 is represented. Besides the evaporation unit 17, this heating/pre-concentration section of the facility comprises a further vapour separator 27, which is connected with the bottom side of the heat exchanger 18, in communication with the interior of the tubes 24, through a duct 28; on such a duct 28, an extraction pump 29 is installed in the nearby of the heat exchanger 18, and furthermore a valve 30 is installed downstream the pump 29. The bottom side of the vapour separator 27 is connected with the intake end of an axial pump 31 by means of a duct 32. The delivery side of the pump 31 is connected with a refining section schematically shown as a block 33, through a duct 34. From the duct 28, a duct 35 branches off, which is directly connected with the refining section 33 by means of the duct 34; on the duct 35, a valve 36 is installed. The outlet end of the refining section 33 is in its turn connected with a concentration section of known type, schematically represented as a block 37. The outlet end of the concentration section 37 is in its turn connected with a pasteurization section of known type, schematically represented as a block 38. Finally, the outlet end of the pasteurization section 38 is connected with a packaging section 39. Besides the hereinabove disclosed equipment pieces, the facility is furthermore equipped with a section of recovery of the flavouring substances contained in tomato. This recovery section comprises a tray-type distillation tower 40, and a surface condenser 41. The distillation tower 40 is equipped in its interior, in its bottom portion, with a coil 42 inside which steam is circulated, which comes from an external steam source schematically represented by means of a block 43 and connected with the coil 42 by means of a duct 44; the reference numeral 45 indicates the drain for the condensate deriving from the condensation of steam inside the coil 42. Above the coil 42, a first set of transversal trays of known type are installed; said first set of trays are schematically indicated by the block 46. Above the first set of trays 46, a second set of transversal trays of known type are installed; said first set of trays are schematically indicated by the block 47. Above said second set of transversal trays 47, at the top of the distillation tower 40, distributor nozzles 48 are installed. The condenser 41 is equipped with an internal tube bundle 49. Inside the tubes of said tube bundle a refrigerating liquid flows. By means of the reference numerals 50 and 51, the inlet of the refrigerating liquid to the condenser 41 and the outlet of the refrigerating liquid from the condenser 41 are respectively indicated. The interior of the distillation tower 40 and the interior of the condenser 41 are in communication with the interior of the vapour separators 19 and 27 through purposely provided pipes. In particular, a pipe 52 is provided, on which a valve 53 is installed, and which puts the interior of the vapour separator 19 in communication with the interior of the distillation tower 40, at a point between the first set of trays 46 and the second set of trays 47. A pipe 54, on which the valve 55 is installed, puts the interior of the vapour separator 27 in communication with the external side of the tube bundle 49 of the condenser 41; a pipe 56, on which the valve 57 is installed, puts the pipes 52 and 54 in communication with each other. The interior of the distillation tower 40 and of the condenser 41 are in communication with each other. In particular, the head of the distillation tower 40 is in communication with the external side of the tube bundle 49 of the condenser 41 by means of a pipe 58 on which the valve 59 is installed, and of the pipe 54. The bottom portion of the external side of the tube bundle 49 is on the contrary in communication with the distributor nozzles 48 by means of a duct 60 on which a centrifugal pump 61 is installed. With the bottom portion of the interior of the distillation tower 40 an extraction pump 63 is connected by means of a duct 62. The top portion of the interior of the distillation tower 40 is connected with the interior of a collection vessel 64 by means of a duct 65 on which an intermediate collection vessel 66 is installed. Inside the vessel 64 a coil 67 is installed, inside which a refrigerating liquid is circulated; by means of the reference numerals 68 and 69, the inlet for the refrigerating liquid fed to the coil 67 inside the vessel 64, and the outlet for the above said refrigerating liquid from the vessel 64 are respectively indicated. The external side of the tube bundle 49 of the condenser 41 is in communication with the interior of a collection vessel 70 by means of a duct 71 branching from the condenser 41. On the duct 71 a vacuum pump 72 is installed. Inside the vessel 70 a coil 73 is installed, inside which a refrigerating liquid is circulated; by means of the reference numerals 74 and 75, the inlet for the refrigerating liquid fed to the coil 73 inside the vessels 70, and the outlet for the above said refrigerating liquid from the vessel 70 are respectively indicated. The processing of tomato with the above disclosed and illustrated facility takes place as follows. Tomato to be submitted to the processing, coming from a sorting plane, not shown in the drawing, is collected inside the hopper 10 and from this is sent by the pump 15 through the duct 12 into the deaerator 11. Inside said deaerator 11, tomato is deaerated by the vacuum pump 13 and therefore it results to be exposed to the action of vacuum at room temperature. From the deaerator 11, tomato is sent by the pump 16 through the duct 23 to the duct 21 of the evaporation unit 17. Once that it has entered the duct 21, tomato is made circulate in closed loop by the pump 20, in the direction as shown by the arrows, inside the duct 21, the inner side of the tube bundle 24 of the heat exchanger 18, inside the duct 22, and inside the vapour separator 19. The external side of the tube bundle 24 is lapped by the steam coming from the kettle 25 through the duct 26. During this processing step, tomatoes undergo a true grinding by the pump 20 and are furthermore heated inside the heat exchanger 18 to such a high temperature that they subsequently evaporate inside the vapour separator 19. A portion of tomato circulating inside said closed loop is intaken by the pump 29, and is sent, through the duct 28, to the vapour separator 27, inside which it cools, with a further evaporation of tomato being anyway obtained. From vapour separator 27, tomato is sent by the pump 31, through the duct 34, to the refining section 33. In such refining section 33, the seeds and the peels are removed from the so semi-finished tomato are removed. From such a refining section 33, the so-refined tomato is sent to the concentration section 37, in which said tomato undergoes a further evaporation and therefore loses most of its liquid content, thus reaching a high concentration level. From the concentration section 37, the so-concentrated tomato is then sent to the pasteurization section 38, in which it is sterilized by means of a high-temperature treatment. The so sterilized tomato concentrate is then sent to the packaging section, in which it is packed inside suitable containers. The content of flavouring substances of tomato, most of which would be lost during the above disclosed processing steps, is recovered as follows. The evaporate of tomato which is formed in the vapour separator 19 is conveyed through the pipe 52 into the distillation tower 40. The evaporate of tomato which is formed in the vapour separator 27 is conveyed into the condenser 41 through the pipe 54, by closing the valve 57 and opening the valve 55, or, alternatively, is conveyed into the distillation tower 40 through the pipes 54, 56, 52, and closing the valve 55 and opening the valve 57. The selection between either of said directions of conveyance can be made as a function of the parameters of the facility, and as a function of an optimization of the recovery of tomato's flavouring substances. Inside the distillation tower 40, a continuous fractional distillation with rectification is carried out. Substantially, through the distillation tower 40 a rising stream of tomato evaporate and a downwards stream of tomato concentrate flow. In particular, tomato evaporate which reaches the head of the distillation tower 40 comes, through the pipes 58 and 54, to the condenser 41, inside which it condenses owing to the heat exchange with the refrigerating liquid which flows inside the tube bundle 49. The pump 61 sends the condensate to the head of the distillation tower 40, wherein it is evenly distributed by the distributor nozzles 48. During the upwards movement of tomato evaporate and the simultaneous downwards motion of tomato condensate, the less volatile fractions of the evaporate condense and by means of their condensation heat, they cause the most volatile fractions to evaporate from the condensate; as a consequence, the rising evaporate gets more and more enriched in more volatile components, whilst the downwards flowing condensate gets more and more enriched in less volatile components. The transversal trays 46 and 47 enable, according to a known technique, a better contact to take place between the evaporate and the condensate, rendering their mutual interaction more complete. A portion of the condensate falling down to the bottom end of the distillation tower 40 evaporates again owing to the heat exchange thereof with steam flowing inside the interior of the coil 42; the remainder portion of the condensate, by now deprived of the flavouring substances, is discharged to the outside through the duct 62 by means of the extraction pump 63. From the top side of the distillation tower 40, the condensate rich in the more volatile components is drawn off through the duct 65. The drawn off condensate is first collected inside the intermediate vessel 66 and then, when it reaches a certain level inside said vessel, is sent to the collection vessel 64 in which it is furthermore cooled by heat exchange with the refrigerating liquid which flows inside the coil 67. These operations are controlled by means of valves 8; the intermediate collection tank 66 makes it possible the amount of drawn off condensate to be controlled. The drawing off of the enriched condensate can be carried out at other points of the distillation tower 40, by means of other drawing-off ducts connected with the collection vessel 64. A portion of the evaporate, containing very highly volatile components, not condensible inside the condenser 41 is intaken by the vacuum pump 72 through the duct 71 and is sent to the collection vessel 70, inside which the pressure is kept at the atmospheric level. The increase in pressure due to the passage through the pump 72, leads to the condensation of said portion of the evaporate at the delivery side of the same pump. The heat generated due to the effect of this condensation is removed by means of the refrigerating liquid which circulates inside the coil 73. It should be observed in this regard that inside the condenser 41 a pressure exists, which is much lower than the atmospheric pressure - which depressure is generated by the vacuum pump 72-, which prevents the above said portion of the evaporate from condensing; this is due to the need for having a pressure much lower than the atmospheric pressure inside the vapour separators 19 and 27, communicating with the condenser 41, so as to allow the ground tomato to evaporate at a low temperature, thus thermal energy being saved, and tomato being prevented from undergoing the deterioration caused by the action of heat. Inside the vessels 64 and 70, the condensate of the more volatile components of the evaporate coming from the vapour separators 19 and 27 is hence collected. Such a condensate results to contain the flavouring substances of tomato, and therefore, summing-up, the content of flavouring substances is recovered inside the vessels 64 and 70 as a liquid rich in flavouring substances. Such a liquid rich in flavouring substances can be then sent to the packaging section 39, as shown in the figure, in order to be fed into the suitable containers together with the tomato concentrate, and give the end product its proper flavour. Or, the liquid rich in flavouring substances can be packed inside containers of its own, in order to be mixed, e.g., at a later time, with processed tomato; such a processed tomato can be the outcome of the hereinabove seen processing method, or of other processing routes, and it can be, besides straight tomato concentrate, also tomato sauce or tomato juice. For the sake of simplicity, one may also choose not to recover flavour-rich condensates coming from very volatile components not condensible inside the condenser 41, but this obviously causes a decrease in recovery yield. In the processing of tomato as hereinabove seen, both vapour separators 19 and 27 are used, according to the processing method known from the prior art and denominated as the "HOT BREAK" route. However, a recovery of the flavouring substances contained in tomato can be obtained also in case only vapour separator 19 is used, i.e., in case of the processing method known as the "COLD BREAK" process. In this latter case, the valves 30, 55, 57 are closed and the valve 36 is opened (whilst in the processing by means of the "HOT BREAK" method, the valve 36 is closed, the valve 30 is opened, and either of the valves 55, 57 is opened and the other one is closed, according to whether the evaporate coming from the vapour separator 27 is conveyed to the distillation tower 40, or to the condenser 41). This furthermore causes the tomato extracted from the pump 29 to directly go to the refining section 33 through the ducts 35 and 34 and the step is therefore skidded of tomato cooling and evaporation inside the vapour separator 27. Anyway, the evaporate which is produced inside the vapour separator 19 is still conveyed to the distillation tower 40 through the pipe 52, and the above seen continuous fractional distillation takes place, with the flavouring substances contained in tomato being recovered. The method for the recovery of the content of flavouring substances of tomato shows to be particularly efficacious and makes it possible a liquid to be obtained, which has a high content of flavouring substances thanks to the condensation and to the enrichment of the condensate in more volatile components. Obviously, such a result can be obtained in a way different to as hereinabove described and illustrated. For example, one might think of a fractional condensation of the evaporate generated by the vapour separators, in which in successive condensation steps the less volatile components are condensed first, and the more volatile components are subsequently condensed up to the last condensation step, in which the most volatile components in absolute are condensed. Obviously, both in case of fractional distillation, and in case of fractional condensation, the equipment pieces can be used, which are regarded as the most suitable ones for the intended purpose (condensers, distillation towers, and so forth). Not necessarily should the fractional distillation be a rectification like in the example. According to a very simple form of practical embodiment, one could simply think of condensing tomato's evaporate, with a condensate being anyway obtained, which contains flavouring substances, although in a more diluted form than as obtained by means of the above disclosed methodology. The fact of operating on the evaporate resulting from the first heating step the ground tomato is submitted to, makes it possible nearly all of the content to be recovered of flavouring substances, which normally gets lost or damaged during the processing of tomato according to the prior art, as discussed in the introduction. By means of the herein disclosed method and facility, besides tomato, also other alimentary products with a liquid content can be processed, such as, e.g., fruit, with the contents of flavouring substances being always efficaciously recovered according to as hereinabove seen. This method for the recovery of the content of the flavouring substances of the alimentary product can be applied both in cases of treatment of the alimentary product in order to obtain a concentrate of the same product at a more or less high concentration level, or in case the alimentary product, after being refined, is not concentrated but is directly sent to the packaging step; in this latter case, the obtained product is not concentrated, or, in case of tomato is tomato juice, and in case of fruit is fruit purèe. Also in this latter case, the content of flavouring substances of the alimentary product upstream the refining section is recovered. In general, this method for the recovery of the flavouring substances is applicable to any types of alimentary products with a liquid content which, during the processing, turns from a whole status to a successive disintegrated status, and at such a temperature as to evaporate, in such a way that the evaporate is condensed and collected, so as to recover the flavouring substances which were given off by the disintegrated product and evaporated. The condensate is preferably enriched in its more volatile components, and in this way a condensate is obtained, which is very rich in flavouring substances of the product. The alimentary product can be disintegrated and substantially heated at the same time, as in the preceding example, or it can be either first disintegrated and then heated; or first heated and then disintegrated. The efficacy of the recovery can be increased by the way of proceeding consisting in disintegrating and heating the product substantially simultaneously, so as not to lose the flavouring substances which are emitted during the disintegration before the heating. Of course, the means for practicing this recovery method, as well as the means for disintegrating and heating the whole product can be various. For example, for the condensation and the enrichment, as above said, those apparatuses can be used, which are normally used for such techniques in other fields; hence, the distillation tower and the condenser, as well as the means for collecting the flavouring condensates as herein disclosed and illustrated are not binding, even if they show to be very efficacious. The heating means for the heating of the alimentary product can be simple, and not of the recycle type, or they can be of a type different from the tube-bundle type, differently to as shown in the preceding example, and furthermore one single vapour separator can be provided for. In general, the means of disintegration, the means for product transfer and the cycle of product transfer downstream the disintegration and evaporation step can be different from as disclosed in the example.

Claims: Method for the processing of an alimentary product with liquid content, in particular vegetable and fruit comprising the steps of: a) introduction of the alimentary product; b) partial concentration of the alimentary product; c) extraction or separation of flavouring substances by evaporation from said alimentary product; characterised by comprising the further steps of: d) deaeration of the whole alimentary product introduced in step a); e) first trituration and evaporation at high temperature of the product obtained in the previous step d), with a first extraction or separation of flavouring substances from said alimentary product; f) further evaporation of the alimentary product coming from step e) at lower temperature, with a second extraction or separation of flavouring substances from said alimentary product; g) refining of said alimentary product obtained in the previous step f), almost free of flavouring substances and thereafter a final concentration; h) pasteurization of the alimentary product concentrate coming from step g); i) packaging of said alimentary product concentrate coming from step h); j) packaging of the flavouring substances recombined with said alimentary product concentrate or separate packaging of said flavouring substances and said alimentary product concentrate. Method according to claim 1, characterised in that said flavouring substances obtained through the steps e) and f) are recombined, distilled and condensed. Method according to claim 1, characterised in that said flavouring substances obtained through the steps e) and f) are treated separately in the way that said flavouring substances coming from the step e) are distilled and condensed and said flavouring substances coming from the step f) are directly condensed. Method according to claim 1, characterised in that said alimentary product with a liquid content is tomato. Facility for carrying out the method according to one of claims from 1 to 4, comprising means (10) for introduction of the alimentary product, connected with a deaerator (11), evaporation means (17, 27) connected with heating means (25,26), concentration section (37), pasteurization section (38) and packaging section (39), characterised in that said evaporation unit (17) comprises a heat exchanger (18) connected through a duct (21) with a centrifugal pump (20) and through a duct (22) with a vapour separator (19), said evaporation unit (17) being also connected through a duct (28) with a further vapour separator (27), which is connected through a duct (32) with an axial pump (31), said vapour separator (27) being further connected through a duct (34) with a refining section (33) and through a duct (54) with a condenser (41) which is in communication, through a duct (71), with a collection vessel (70), said vapour separator (19) being also connected through a duct (52) with a distillation tower (40) in communication, through a duct (65), with a collection vessel (64), said collection vessels (64,70) being connected with the packaging section (39). Facility according to claim 5, characterised in that said ducts (52,54) are connected through a duct (56) and a valve (57).

Inventors: ARELLI PIER LUIGI, SOMMI FRANCO, ARELLI, PIER LUIGI, SOMMI, FRANCO
Applicants: MANZINI COMACO SPA, MANZINI COMACO S.P.A.
Application year: 1989
Main classification: A23B7
IPC codes: A23L1, A23L2, A23L3