IL31959A - Manufacture of beverages and the like - Google Patents

Description

'- f V, nainai nixptpa nix*a o' i aw Improvements in the manufacture of beverages and the like «7. LYONS & CO PAIiY LIMITED C. 30286 This invention relates to the production of citrus fruit products. More particularly, the invention concerns a process for the production of citrus fruit products in which a higher yield of useful end product is obtained from a given quantity of whole fruit, and making use of what but for the invention, would normally be regarded as a waste product. She invention is applicable to citrus fruit generally, but as oranges are the citrus fruit used commercially in the greatest quantity, it is convenient to describe the Invention in relation to the production of an orange fruit product* It is to be understood, however, that the invention can be used in connection with the production of other citrus or non-citrus fruit products.

Oranges are widely used for the preparation of orange beverage concentrates and for this purpose the fruit is comminuted by suitable means* The liquid products of comminution are then separated from th© solids and used to produce the concentrateI the solid products are normally regarded as waste products and are not further used.

It is known from the publication "Chemical Engineers Handbook" edited by John H. Perry, fourth edition, at pages 19-59 and 19-40 that in the recovery of juice from canes, expression on three-roll mills is combined with solvent extraction, using water, in a series of alternating or simultaneous operations. It is said that the cane is first crushed dry, but at selected points in the later mills water or weak liquor is added as a spray or bath to improve sugar recovery.

With the invention there is provided a method of and appaea- us for processing these residual comminuted fruit solids such that a further liquid product is obtained which after additional treatment affords the base of or a supplement for a base for of the liquid product extraction from the solid content is in- ^ creased.

According to the present invention there is provided a are hod of obtaining a liquid citrus fruit extract which comprises mixing with an aqueous liquid an initial material comprising the solids resulting from a process in which comminuted citrus fruit has been treated to extract primary liquid components thereof and separating secondary liquid constituents from said mixture.

The starting material for the process according to the -'ίί' invention is a by— roduct, normally considered to be a waste product, resulting from citrus fruit processing. One source of starting material is a process in which whole fruit is comminuted by means of rapidly rotating disc knives, the comminuted fruit then being added to a sugar syrup, and allowed to stand for an extraction period usually some minutes, ίηβ principally liquid product ie the product which is aioostcwholly liquid, but which may contain minimal quantities of fruit solids dispersed in the liquid is then separated from the solids j' the liquid extract thus obtained affords the base of an orange product of good flavour and good keeping qualities, and the solids can be used as the starting material, Another starting material &s by-product from a process in which the fruit is first comminuted by rotating disceknives as before, the comminuted fruit being passed to a screw extractor where the principally liquid product of comminution is separated from the solid materials by a means which involves the imposition of a gradually increasing pressure.

An apparatus for earrying put this latter process may include a conveyor on which whole fruit is brought to an elevator where it is elevated and deposited in a hopper. The fruit is released from the hopper in batches, each batch being dropped into a separate section of a Ferris wheel where it is heat-treated for a short period and to such an extent that the skin of the fruit is at a higher temperature than the interior thereof. The heated fruit is discharged from the Ferris Wheel onto parallel jigging $■ conveyors and then fed through vertical guides to a bank of so-called converters, comprising the high-speed comminuting disc knives. The comminuted fruit from all the converters is deposited into a common hopper from which it discharges into a screw press extractor. The screw press extractors are of the kind in which gradually increasing pressure is imposed on the comminuted fruit. The primarily liquid products of comminution are drawn off for further processing: the primarily solid products are used as the starting material' for the present process. This starting material is passed to one or more extraction stages each carried out in a screw press extractor. The mere use of a further extractor to obtain more of the fruit product is not feasible, but in the -present process the starting material is mixed with a quantity of liquid, specifically water, and then subjected to further extraction in the screw press. A more efficient extraction is obtained when the water is added in a series of batches rather than in a single batch. Extraction can then be in a single stage or in a series of stages to give optimum, extraction.

It will normally occur that the second and any subsequent extracts from the fruit solids will give progressively smaller concentrations of extract than the first, and the subsequent extract may be concentrated to the required strength.

The flow of extracting liquid may alternatively be arranged countereurrent to the solids from which the solubles are being extracted. This process, which may either be stepwise, or continuous in a suitable apparatus x^ould result in a smaller volume of more concentrated extract.

'With the waste from certain varieties of fruit, an improved quality of liquid extract can he obtained during the additional ; extraction process if a solution of citric acid or of other 1 organic acids or mixtures of acids is used as the added liquid.

I ife use of such a solution is also "beneficial in that enzymatic I or microbiological activity in the processing apparatus is ! thereby discouraged.

! In order that the invention may be well understood I there will now be described an embodiment thereof, given by way of example only, reference being had to the accom-I panying drawings, of which: ; Figure 1 comprises a flow diagram showing the : various stages in the treatment of the comminuted fruit - ! solids in accordance with one embodiment of the invention; i i Figure 2 comprises a flow diagram illustrating ! the stages of another embodiment of the invention.

I Like elements are denoted by like reference I numerals in the two Figures. ί I In the embodiment shown in Figure 1 whole fruit i 1 is comminuted in a comminuting apparatus 1 such as -Ghat I described above and the liquid product extracted in a press screw extractor 2. The extractor suitably comprises a feed screw 3, of gradually decreasing pitch along its length towards its delivery end, fitting closely within a perforated retainer 4-, The stem of the feed screw may also increase in diameter along the length of the screw or the diameter ' of the perforated container may decrease as shown so that a gradually increasing pressure is exerted upon the material within the extractor as it progresses along the feed screw. comminuted fruit is caused to be expressed by the action of the feed screw, and passes through the perforations of the retainer to be discharged at as the primary liquid constituent, whilst the principally solid materials discharge from the end of the feed screw at 6. The screw extractor is driven by means of a suitable prime mover such as an electric motor 7 through a belt drive 8 and worm drive 9· ' Accordingly, the waste solid materials are conveyed by a screw worm conveyor 10, which may be driven by an electric motor 11 by way of a belt drive 12 and a worm drive 13, to either of two mixing tanks 14A, 14B therein to be treated by and thoroughly mixed with a citric acid solution. The citric acid solution preferably comprises a 1% by weight solution- of citric acid in water, and is made up and stored in a vessel 15 from which it is discharged into the mixing tanks 14A, 14B. The vessel 15 and those mixing tanks have standard Osborn marine type,-rotary agitators 16A, 16B, 16C respectively to promote a thorough mixing of their contents.

The acid solution acts as the extraction vehicle to enable those components which can be dissolved in or conveyed by the liquid to be extracted. When such a soluti< is subjected to a second stage screw extraction treatment to be described the volume of solution mixed with the solid materials is approximately equal to that of the liquid product removed in the first screw extraction. As an alternative to this batch treatmen , the citric acid solution can be added continuously by a continuous metering and mixing process.

The volume of citric acid solution which is added to the waste, preparatory to a further extraction is of some importance, and preferably the volume of solution added is such that when extraction takes place zhe same type of pressure is imposed on the material in the press as in the first or primary extraction, and to obtain a similar degree of extraction. It is usually more convenient if the same type of extractor is used at each stage but this is not necessarily so; if a different type of extractor is used it may be appropriate to use a different volume of additive citric acid solution.

After a suitable period of agrca-uion, the mixture of peel and extracting solution is pumped by a rotary pump 17 to a second screw extractor 18. The construction and operation of that screw extractor is similar to that of the extractor 2 so that a secondary liquid extract is obtained from the mixture and is discharged at 14, leaving waste solid materials which are discharged from the extractor at 20.

As before, extractor IS may be driven from an electric motor 21 by way of a belt drive 22 and a worm drive 2$.

The secondary liquid extract is discharged from the screw extractor 18 along feed paths 2 A, 24-B to two holding tanks 2^ , 253 where it is stored before being fed through a plate heat exchanger 26 in which it is pasteurized. The reason for pasteurising is primarily to stop any en¾.ymatic action, and the pasteurising conditions should be selected accordingly. By way of example only, the liquid product can be first subjected to a high temperature for a short rime in a heat exchange circuit 27, such as 205°J? for a period of 60-90 seconds. The heatin medium can be steam or water. The liquid product is then cooled in a heat exchange circuit 28 by any suitable cooling medium.

Prom the heat exchanger 13, the liquid product is subjected to a separating operation to remove part of the suspended solids therefrom. Thus, the liquid product can be passed through a screen 29 vibrated by suitable means, such as an eccentric vibrator 30. The screening process separates a pulp-like material at 31; the screened liquid is passed through a conduit 32 to an evaporator concentrator 33 after which the concentrated extract from the evaporator may be taken for use at 36 or the pulp from 31 ma , if required be returned to and mixed with the concentrated liquid in a mixer 3 to produce the final product at 35- The evaporator-concentrator 32 is of the vacuum type, and removes a proportion of the water content until a desired concentration of the final product. In practice, a concentration of 32° brix has been found suitable, though other concentrations can of course be used.

Figure 2 illustrates an alternative embodiment of the invention in which citrus fruit is again comminuted .in an apparatus 1 and the resultant pulp is fed into a screw extractor 2 , yielding a primary liquid extract at and solids at 6. The solids are passed to a counterflow apparatus 40 in which the solids are moved by a helical conveyor 41, driven by an electric motor 42 by way of a belt drive 43 and a worm drive 44 to traverse the solids against ' the flow of an aqueous solution of citric acid directed into the counterflow apparatus from a mixing valve 5· In its passage through the counterflow apparatus the aqueous liquid extracts an increasing proportion of liquid constituents to form a secondary liquid extract which is discharged from the apparatus at 4-6. The secondary-liquid extract is then pasteurised by treatment in a heat exchanger 26, separated from the pulp in a separator 29 and concentrated in a vacuum evaporator 33 &s described in relation to Figure 1.

The concentrated liquid extract may be re-mixed with the pulp in a' mixer 3^ to yield a product at 35 or may be taken from the evauorator at 36.

The concentrated product can be preserved in one of several ways which are commonly used in the industry.

The waste product obtained from the screw press 10 can be reprocessed in a manner and by means similar to that described; while in the described embodiment of the invention one additional screw press extractor is used, < further such extractors, or other types of extractor, can be used, and, in general, as many extraction stages as are required can be used, each followed by pasteurising and concentration, and in each case the quantity and concentration of the solution introduced to the waste solids material prior to extraction is selected to give the best extraction conditions in the extractor used.

Claims (10)

31959/2 WHAT WE CLAIM IS:- *' » » ·· ·

1. The method of obtaining liquid citrus fruit extracts which comprises subjecting whole citrus fruit to a comminuting process to obtain a primary material, passing said primary material through a first extractor to separate therefrom a primary liquid extract and a paste like fruit residue, mixing said fruit residue with a volume of an aqueous liquid equal to that of the primary extract and passing said mixture through a second extractor to separate therefrom a secondary liquid extract having approximately the same constitution as a dilution of said primary liquid extract with said aqueous liquid.

2. The method according to claim 1 wherein said

3. I aqueous liquid is water. 3· T e method according to claim 1 wherein said aqueous liquid is a 1% by weight solution of citric acid.

4. . The method according to claim 1 wherein said aqueous liquid comprises secondary liquid constituents extracted by said method from other fruit residues.

5. · The method according to any one of the preceding claims wherein said fruit residue and said aqueous liquid are mixed by counterflow to obtain said mixture and to separate said secondary liquid constituents therefrom. - 1 - 31 59/2

6. The method according to any one of claims 1 to 4· wherein predetermined quantities of said whole fruit residue and said aqueous liquid are stirred together in a container to obtain said mixture and said mixture is separated into waste residue and said second ary liquid constituents in a screw press extractor.

7. · T e method according to any one of the preceding claims wherein said secondary liquid extract is pasteurised.

8. The method according to claim 7 wherein said extract is pasteurised by heating in a heat exchanger to a temperature of 05°F for a period of 60-90 seconds

9. The method according to any one of the preceding claims wherein said pasteurised liquid extract is separated from its pulpy constituents and concentrated by vacuum evaporation.

10. The method according to claim 8 wherein said concentrated liquid extract is re-mixed with said separated pulpy constituents.