WO1997021476A1

WO1997021476A1 - A method and an apparatus for recovering and recycling aroma substances

Info

Publication number: WO1997021476A1
Application number: PCT/SE1996/001627
Authority: WO
Inventors: Karl MÅRTENSON
Original assignee: Tetra Laval Holdings & Finance S.A.; BERENDAHL, Gunnel
Priority date: 1995-12-11
Filing date: 1996-12-10
Publication date: 1997-06-19
Also published as: AU1073097A

Abstract

The disclosure relates to a method and an apparatus for recovering and recycling aroma substances in a process for the production of products based on berries and/or fruits, for example jams, cordial etc., in which the berries and/or fruits are cooked in water at reduced pressure for driving off released gases and penetrating the cooking mass. Gases driven off from the cooking mass are cooled for the formation of a first aroma-poor gas phase and a first aroma-rich concentrated liquid phase which is separated from the first aroma-poor gas phase and is recycled to the cooking mass. The separated first aroma-poor gas phase is once again cooled for the formation of a second aroma-poor gas phase and a second aroma-rich condensed liquid phase which is separated from the second aroma-poor gas phase and is recycled to the cooking mass. As a result of this cooling of the driven-off gases in two stages and recycling of both of the thus formed, condensed liquid phases to the cooking mass, a pratically complete recovery, recycling and re-use of otherwise lost aroma substances has become possible.

Description

A METHOD AND AN APPARATUS FOR RECOVERING AND RECYCLING AROMA SUBSTANCES

TECHNICAL FIELD The present invention relates to a method for recovering and recycling aroma substances in a process for the production of cordials, jams or similar products based on berries and/ or fruits, in which process berries and/ or fruits are boiled in water at reduced pressure for driving off released gases and penetrating the berries and /or the fruits. The present invention also relates to an apparatus for carrying the method into effect, the apparatus comprising an evacuable vessel for boiling berries and/ or fruits in water at reduced pressure and a conduit connected to the vessel for evacuation of the vessel and removal of released gases.

BACKGROUND ART

Cordials, jams and similar products based on berries and/ or fruits are traditionally produced by a boiling process in which the berries and /or the fruits selected for the product in question are boiled in water together with other additives selected for producing the product, such as, for example, pectin, sweeteners etc., for driving off released gases and penetration of the berries or fruits, respectively. After the boiling cycle which takes place with agitation of the mass, the mass is separated by screening/ filtering into a solid and a liquid fraction for further processing in a per se known manner for preparing the finished product. On an industrial scale, this production is put into effect using large pans or vessels into which are filled predetermined quantities and proportions of berries and fruits, respectively, together with the requisite quantity of water and other selected additives. The pan or vessel is closed and the filled mass is heated and boiled according to a predetermined timetable for removing gases through an outer conduit connecting to the interior of the vessel. In order to avoid local overheating and to ensure a uniform and homogeneous boiling cycle, the vessel is normally provided with interior agitator means which continuously keep the mass in motion throughout the entire boiling cycle. Since berries and fruits are generally heat-sensitive and can easily disintegrate or be destroyed if they are exposed to lengthy cooking at excessively high boiling temperatures, the industrial boiling cycle is often carried out at reduced pressure at which the boiling point of the water is lower than at normal atmospheric pressure, and the boiling cycle can thus be carried out at lower temperature which is more gentle on the berries or fruits, respectively. This reduced pressure is catered for by means of an evacuation pump which is in communication with the interior of the cooker. One serious problem in connection with the above-described conventional production process is that not only released gases (which it is desirable to release and remove from the mass), but also fragrant and aromatic vapours formed in the cooking process are driven off. Such vapours which, for the greater part, consist of water, also include a not insignificant proportion of the natural aroma substances of the berries or fruit which it is desirable to retain in order to impart to the finished product a natural flavour which is as saturated in fragrance and aroma as possible. In order to compensate for this inevitable loss of valuable, natural aroma substances and in order thereby to counteract the interrelated and undesirable effects on the flavour of the finished product, it has therefore proved necessary to add to the boiled mass of the fruit and / or berries synthetic flavourings which, to some degree but not entirely, have succeeded in restoring the desired natural, pristine flavour of the products.

OUTLINE OF THE INVENTION

There is thus a great need in the art to be able to carry out the above- described industrial production process in such a manner that none (or but a minimum) of the natural aroma substances of the berries or fruits is lost during the process and the finished product may thereby retain the natural, pristine flavour of the berries or fruit to the greatest possible extent, without the need to supplement with flavourings produced artificially.

In accordance with the present invention, this need has been satisfied by a method which has the characterizing features as set forth in appended Claim 1.

The condensed, highly fragrant liquid phase which is rich in aroma may be collected, stored and re-used on another occasion, but is preferably recycled to the berry/ fruit mass from which it originally derived in order to restore the natural, pristine aroma content of the mass.

The simultaneously separated gas phase, which is poor in aroma substances which, for the greater part, are to be found in the liquid phase which is condensed by cooling, can be removed from the process together with the released gases, but is preferably subjected to a second cooling for the purpose of condensing and extracting additional residual aroma substances.

In the same manner as previously, this second liquid phase condensed by cooling can also be stored and re-used on another occasion, but is preferably recycled to the berry/ fruit mass from which it originally derived. Preferably, both of the liquid phases condensed by cooling are combined and recycled together to the boiled berry/ fruit mass.

According to another aspect, the present invention also realises an apparatus for recycling aroma substances in a process for the production of cordials, jams or similar products based on berries and/ or fruit. The apparatus according to the invention has the characterizing features as set forth in the characterizing clause of appended Claim 6, and expedient embodiments of the apparatus according to the invention have further been given the characterizing features as set forth in appended subclaims 7 to 12.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

The present invention will now be described and explained in greater detail hereinbelow, with particular reference to the accompanying Drawing which schematically illustrates an apparatus for carrying out the method according to one preferred embodiment of the present invention. The accompanying Drawing thus schematically shows an apparatus by means of which aroma substances may be recycled in the manner according to the present invention in a continuous industrial process for preparing cordials, jams or similar products based on berries and /or fruits.

DESCRIPTION OF PREFERRED EMBODIMENT

The apparatus comprises a vessel 10 serving as cooker and provided with an inlet 11 for starting materials (such as berries and /or fruits) which is to be cooked. The vessel 10 has an outlet 12 through which the cooked mass is emptied after the completion of the cooking cycle. The inlet 11 and outlet 12 need not necessarily be discrete from one another as shown on the Drawing, but instead the outlet 12 may be employed for both replenishment of starting materials and for emptying of the cooking mass. In this case, the need for the separate inlet 11 is thus obviated. The vessel 10 is further provided with an outlet 13 for evacuation, i.e. pressure reduction, and removal of gases which are released from the mass during the cooking operation.

The vessel 10 is connected to a first cooler (condenser) 20 via a conduit

21 which is in communication with the outlet 13 of the vessel 10, and an inlet

22 at the first condenser 20. At the lower region of the first condenser 20, there is an outlet 23 for removal of a liquid process flow after passage through the condenser.

The condenser 20 may, for example, be a twin-walled column with separate inlet 24 and separate outlet 25 for a coolant which is intended to flow through the space between the walls of the column for cooling the process flow through the column in a flow cycle 26 which is discrete from the process flow.

Via a conduit 27 connected to the outlet 23, the first condenser 20 is connected to the inlet 31 of a separator 30 provided with inlet 31 and outlet 32 for separating the process flow removed through the outlet 23 into a liquid phase and a gas phase. The separator 30 may be any optional type of suitable, conventional separation device and, since those skilled in the art are thoroughly familiar with such devices, any further description of such devices in order to illuminate the present invention would appear to be superfluous.

The separator 30 is connected to a second cooler (condenser) 40 through a conduit 35 in communication with the outlet 32 of the separator 30, and an inlet 41 at the second condenser 40. At the lower region of the second condenser 40, there is an outlet 42 for removing condensed liquid, and at the upper region, there is an outlet 43 for removal of gases evacuated from the second condenser by means of a pump Pl in a conduit 44 connected to the outlet.

In the same manner as in the first condenser 20, the second condenser 40 may, for example, be a twin-walled column with separate inlet 45 and separate outlet 46 for a coolant which is intended to flow through the space between the walls of the column for cooling the process flow through the column in a flow cycle 47 discrete from the process flow.

Although it will already be clearly apparent from the foregoing description, it should nevertheless be pointed out that the pump Pl in the conduit 44 in the apparatus according to the present invention is in flow connection with the vessel 10 serving as the cooker through interjacent conduits 21, 27, 34 and interjacent devices 20, 30 and 40 in such a manner that the pump Pl may be employed, on the one hand, for evacuating released gases from the vessel 10 and, on the other hand, for reducing the pressure within the vessel 10 to a suitably reduced cooking pressure. The pressure Pl further serves the purpose of driving out of the vessel 10 evacuated gases through the above-mentioned interjacent conduits and devices in a continuous process flow throughout the entire production and recycling process, as will be described in greater detail hereinbelow.

It will further be apparent from the accompanying Drawing that the outlet 33 of the separator 30 is in communication with an outer conduit 48 which has a valve VI, and that the conduit 48 is in turn connected to a conduit 49 which has a valve V2 between the outlet 33 and the valve VI. The outlet 42 of the second condenser 40 is in communication with an outer conduit 50 which has a valve V3, and the conduit 50 is in turn connected to a conduit 51 which has a valve V4 between the outlet 42 and the valve V3.

The conduits 48 and 50 are connected to a common return conduit 52 which is connected to an inlet 14 to the cooker vessel 10. Between the inlet 14 and the connection point of the return conduit 52 to the conduit 48, the return conduit 52 has a valve V5 and a pump P2.

The illustrated arrangement functions as follows for recycling aroma substances in a process for the production of cordials, jams or similar products based on berries and / or fruits using the method according to the invention.

Selected berries and /or fruits together with water and other suitable additives for producing the product, e.g. pectin, sweetener (sugar) etc., are introduced in metered quantities and mutual proportions into the vessel 10 through the inlet 11. The aqueous mass of starting materials is heated and brought to boil in the vessel, at the same time as the inner pressure inside the vessel is reduced to a suitably low pressure by evacuation by means of the pump P2 in the conduit 44. The reduced pressure may be selected freely, but is preferably selected in such a manner that the boiling point of the water at the selected pressure is gentle on the berries and /or fruits.

Gases which have been released as a result of the cooking process and likewise formed water vapour containing aroma substances are driven off from the vessel 10 through the outlet 13 and led via the conduit 21 into the first condenser 20 for condensing by cooling, for the formation of a mixture of condensed liquid and gas. The cooled mixture of condensed fragrant and aroma-rich liquid and non-condensed gas (substantially water vapour and residual non-condensed aroma substances) is removed from the first condenser 20 through the outlet 23 and led through the conduit 27 into the separator 30 where the fragrant liquid phase rich in aroma is separated from the non-condensed gas phase. The non-condensed gas phase is removed from the separator 30 via the outlet 32 and is led further through the conduit 34 into the second condenser 40 via the inlet 41. In the second condenser 40, the gas is once again cooled for the formation of a second condensed liquid containing aroma substances and a non-condensed aroma-poor gas of substantially air and water vapour and gases released from the berries and/ or fruits which are driven off from the second condenser 40m through the conduit 44 with the aid of the pump Pl.

The condensed, aroma-rich liquid is removed from the separator 30 through the valved (VI) conduit 48 and the condensed second aroma- containing liquid is removed from the second condenser 40 through the valved (V3) conduit 50.

Both of the aroma-containing condensed liquids from the separator 30 and the second condenser 40, respectively, may be recycled separately or together with one another in optionally selected mutual proportions to the vessel 10 through the common return conduit 52 connected to the inlet 14 of the vessel 10 or, if desired, be accumulated separately and re-used separately or together with one another in another process for the production of cordials, jam or other products based on berries and /or fruit.

If it is desired to recycle both of the condensed, aroma-containing liquids to the cooking mass from which they were originally extracted, the valve V2 in the conduit 49 and the valve V4 in the conduit 51 are closed, at the same time as the valve VI in the conduit 48, the valve V3 in the conduit 50 and the valve V5 in the return conduit 52 are opened.

If only the condensed liquid extracted from the separator 30 is to be recycled to the vessel 10, the valve V2 in the conduit 49 and the valve V3 in the conduit 50 are closed, at the same time as the valve VI in the conduit 48, the valve V5 in the return conduit 52 and the valve V4 in the conduit 51 are opened.

If, on the other hand, only the aroma-containing liquid extracted from the second condenser 40 is to be recycled, the valve VI in the conduit 48 and the valve V4 in the conduit 51 are closed, at the same time as the valve V2 in the conduit 49, the valve V3 in the conduit 50 and the valve V5 in the return conduit 52 are opened.

If neither of the two aroma-containing condensed liquids are to be recycled to the cooking mass in the vessel 10 but are instead to be accumulated and stored separately or together with one another for re-use in another process, the valve V in the conduit 48 and the valve V3 in the conduit 50 are closed, at the same time as the valve V2 in the conduit 49, and the valve V4 in the conduit 51 are opened. Separate pumps are then connected to the conduits 49 and 51 for pumping out the condensate. It will thus be apparent from the foregoing description that it is possible by means of the present invention to recycle practically all aroma substances driven off from a fruit and / or berry cooking process and, in an advantageously optional manner to recycle these to the process, at the same time as the method according to the present invention may readily be reduced into practice employing simple, already available process equipment. One particularly valuable advantage inherent in the present invention is that one and the same pump (Pl) may be used, on the one hand for reducing the pressure inside the cooking vessel and, on the other hand, for driving the aroma-containing gas evacuated from the vessel to and through the subsequent process stages.

It will be obvious to a person skilled in the art that a multiplicity of modifications and alterations may be put into effect without departing from the spirit and scope of the inventive concept as herein disclosed. Such modifications and alterations of individual details to the body of this description therefore lie within the spirit and scope of the inventive concept as defined in the appended Claims.

Claims

WHAT IS CLAIMED IS:

1. A method of recovering and recycling aroma substances in a process for the production of cordials, jams or similar products based on berries and/ or fruits, in which method the berries and/ or fruits are cooked in water at reduced temperature for driving off released gases and penetration of said berries and/ or fruits characterized in that gases driven off from the cooking mass are cooled for the formation of a first, aroma-concentrated liquid and a first aroma-poor gas; and that the first aroma-concentrated liquid is separated and recovered.

2. The method as claimed in Claim 1, characterized in that the separated and recovered first aroma-concentrated Iiquid is recycled to and mixed with the cooking mass.

3. The method as claimed in Claim 1 or 2, characterized in that the first, aroma-poor gas is cooled for the formation of a second aroma-concentrated liquid and a second aroma-poor gas; and that the second aroma- concentrated liquid is separated and recovered.

4. The method as claimed in Claim 3, characterized in that the separated and recovered second aroma-concentrated liquid is recycled to and mixed with the cooking mass.

5. The method as claimed in Claim 4, characterized in that the separated and recovered second aroma-concentrated liquid is mixed with the separated and recovered first aroma-concentrated liquid.

6. An apparatus for recovering and recycling aroma substances in a process for the production of cordials, jams or similar products based on berries and/ or fruits as claimed in Claim 1, the apparatus comprising an evacuable vessel (10) for cooking berries and /or fruits in water at reduced pressure, and an outer conduit (21) connected to the vessel (10 for driving off released gases, characterized in that said outer conduit (21) is connected to a first cooler (condenser) (20) in which said gases are disposed to be cooled for the formation of a first, condensed aroma-concentrated liquid and a first aroma-poor gas phase; and that the first condenser (20) is, via a conduit (27), connected to a separator device (30) for separating and recovering the first aroma-concentrated liquid.

7. The apparatus as claimed in Claim 6, characterized in that the separator device (30) is connected to the vessel (10) via a conduit (48, 52) for recycling the separated and recovered first aroma-concentrated liquid.

8. The apparatus as claimed in Claim 6 or 7, characterized in that the separator device (30) is, via a conduit (34), connected to a second cooler (condenser) (40) in which the first aroma-poor gas is disposed to be cooled for the formation of a second aroma-concentrated liquid and a second aroma-poor gas.

9. The apparatus as claimed in Claim 8, characterized in that the second cooler (40) has an outlet (42) for removal of the second aroma-rich liquid.

10. The apparatus as claimed in Claim 9, characterized in that the outlet (42) for the second aroma-rich liquid is connected to the vessel (10) for recycling the second aroma-concentrated liquid.

11. The apparatus as claimed in Claim 10, characterized in that the outlet (42) for the second aroma-concentrated liquid is connected to the conduit

(52).

12. The apparatus as claimed in any of Claims 8 to 11, characterized in that the second cooler (condenser) (40) has an outlet (43) which is in communication with an evacuation pump (Pl) for driving off the second aroma-poor gas.