DE1442265A1 - Process and device for converting starch and other polysaccharides into products containing dextrose and maltose - Google Patents

Description

Karl Kristian Kobs Kreiyer , Aarhus-Viby / Denmark

Method and device for Höwyei'L'X'erung of Starch and other polysaccharides in products containing dextrose and maltose.

The invention "relates to a method and an apparatus for converting starch and other polysaccharides into products containing dextrose and maltose »The invention relates in particular to a process, ie. the Polysaccharides to be converted first in a first process stage of enzyraati see liquefaction and then are subjected to enzymatic saccharification in a second process step «

The end product obtained by such a process consists essentially of dissolved dextrose and / or maltose and small amounts of other sugars as well as of undissolved products such as unconverted or partially converted polysaccharides and insoluble substances from the starting material.These undissolved products must therefore be removed by filtration, for example "before the dextrose and / or containing maltose solution are concentrated by evaporation of the solvent kanne However, it has been found that the filtration of the by the" final product obtained to known methods by the undissolved components "is hindered _f which the pores of the filter" _t .

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clog "This is how the filtering process takes shape ' difficult and time consuming. * /

The invention is primarily based on the object this Haent rush to the aforementioned known method avoid ο

In which. Process according to the invention for converting starch and other polysaccharides into dextrose and maltose-containing products, the polysaccharides to be converted first being subjected to enzymatic liquefaction in a first process stage and then, in a second process stage, enzymatic saccharification, This object is primarily achieved in that the liquefaction in the first process stage is carried out in such a way that the polysaccharide medium, to which a liquefying enzyme has been added, is first pressed through a first heat exchanger and thereby without being introduced at all is heated by steam to liquefaction temperature, is then passed through one or more converter tubes while maintaining an essentially the same temperature, then passed through a second heat exchanger and ^{heated to a temperature well above UOO 0} C and for some time at this temperature and below a m pressure is maintained at

where there is no formation of steam, and then to the Condensing temperature is cooled - and another 'Adding liquefaction enzymes to complete the liquefaction of the medium receives "

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The combination of these process steps results in a considerable reduction in the content of undissolved constituents achieved in the final product without an excessive increase in the total "consumption of liquefying enzyme. It is assume that this surprising effect is explained as follows can be.

During the flow through the first heat exchanger, the polysaccharide medium, such as, for example, a starch milk, gelatinizes when the lower limit of the gelatinization temperature range is reached. However, when the starch medium is finally heated to a temperature within the liquefaction temperature range, its temperature will be close. the upper limit of the gelatinization temperature range, so that the starch medium becomes liquid again under the influence of the thermal treatment. At this point in time, the enzymatic liquefaction begins, and this liquefaction reaches such an extent that the starch medium can be ^{heated to a temperature well above 100 ° C. during the flow through the converter tube or the converter tubes and through the second heat exchanger without} that gelatinization problems occur.

Due to absorption of water by the starch particles during Gelatineerung are the molecular bonds that di € crystalline surfaces of the starch particles linked together (the so-called. "Crystal Lite") loosened "

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so that the liquefying enzyme breaks the molecular bonds during the subsequent enzymatic liquefaction of the Strength in the converter can attack. Otherwise can apparently the liquefying enzyme in the molecular bonds attack the crystalline surfaces of the starch particles only with difficulty, if the starch particles are not one have been subjected to preparatory treatment «It must be assumed that the unaffected or partial disassembled molecular bonds which cause difficulties in filtering the converted end product from the 'known processes'

During the next process step of the invention, namely the heating to a ^{temperature well above 10O 0} C, a thermal breakdown of the molecular bonds takes place, so that the starch particles can easily be attacked by the saccharification enzymes after cooling to the liquefaction temperature in the second process stage ν

Since the liquefying enzyme is destroyed when the starch medium is ^{heated to a temperature above 10O 0} O, it is necessary to add more enzyme to complete the liquefaction. It should have been expected that the process according to the invention would be uneconomical because it required a relatively high total consumption of liquefying enzymes. However, it was found that the total enzyme consumption was kept relatively low

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and that the very important progress of the aimed "better filterability of the converted end product clearly justifies the double addition of enzymes.

The advantages of the method according to the invention "are based on a combined effect of the mechanically, thermally and enzymatically generated viscosity changes during the Flow of the medium through the first heat exchanger and the converter tubes «. The thermally induced increase in viscosity, the one at the lower limit of the cladding * - treatment temperature range takes place, is neutralized by a mechanically generated viscosity reduction as a result the internal heat in the medium when it is pressed through the first heat exchanger »This mechanical The viscosity reduction produced is in the course of the subsequent treatment by an enzymatically produced viscosity s decrease increases, which sets in when the temperature of the medium decreases for the effectiveness of the Enzymes approaching optimal temperature. The heating would now continue immediately until the maximum temperature was reached in which the thermal breakdown of the molecular bonds takes place, a strong and rapid one would be Destruction of the enzyme causes »In this case a large excess of enzyme would be required if the enzymatic The viscosity reduction produced is believed to play some significant role within the overall viscosity reduction in the course of the heat treatment. If you

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on the other hand, ater would only have to rely on the mechanically produced reduction in viscosity until the thermally produced reduction in viscosity becomes effective. is _s would use a starting material having a relatively high starch concentration, have the effect that the starch medium during the rest of T-Eils the heat treatment, the flow would be a very ken resistance opposed Bs therefore large. Risk of blockages unless excessively high pressures are applied »

By interrupting the heating according to the invention as soon as the temperature has reached a value close to the temperature optimal for the effectiveness of the liquefying enzymes, and by further heating when the enzyme has acted on the starch and caused a certain reduction in viscosity eliminates the risk of clogging during subsequent heating to the maximum temperature, even if only a very small amount of enzyme is used, _etc.

As can be seen from the discussion above, it is very important when the method according to the invention for conversion a starting material with a relatively high concentration of E ply saccharide applied, that in the first heat exchanger a mechanical viscosity reduction is generated, which is capable of a significant Holle to play within the described interaction between the various factors .. In further

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Embodiment of the invention, the first heat exchanger is therefore provided with slot-like passages through which the medium is pressed with such pressure and speed that an essentially thixotropic viscosity reduction of the medium is caused Starch medium assumes a completely different consistency when it is subjected to internal shear forces than when such forces do not occur. "This phenomenon is referred to here as tixotropy", as it is similar, for example, to the production of a concrete mixture which can be kept plastic for a long time by stirring while it solidifies relatively quickly if left to stand. ”In the method according to the invention, the shear forces are generated in the starch medium by forcing the medium through the slot-like passages during heating, so that the gelatinized and non-gelatinized parts of the medium are forced to "form a homogeneous mass on which the liquefying enzyme can act well". The liquefying enzyme can thus become effective and contribute to a reduction in viscosity, which supplements the thixotropic reduction in viscosity. When the medium is pressed through the slot-like passages, an increasing amount of starch gelatinizes, so that at the same time as this progressive gelatinization, a progressive enzymatic liquefaction occurs, which a viscosity reduction "causes and the increase in viscosity caused by progressive gelatinization is reduced. Ultimately, a state occurs, " 809811/034 8

"in which the enzymatic liquefaction brought about" Viscosity reduction is sufficiently high to keep the mass liquid and without the influence of internal shear forces to let flow © When this state is reached, the starch medium leaves the slot-like passages and flows into the converter, so that, as mentioned above, the enzyme can develop its effect before the medium is up a temperature is heated at which the molecular bonds are thermally broken down.

The medium is preferably passed through during the flow the first heat exchanger, the converter tube or the Converter tubes and the second heat exchanger one, pulsating Subject to progressive movement, for example by using a diaphragm or piston demand pump. This continues to increase in bulk the shear forces that occur during gelatinization Reduce viscosity »The pulsating progressive movement also serves to prevent deposits of gelatinized starch on the converter tube walls. All in all has the pulsating progressive movement on the flow conditions the effect that the medium as a whole is pushed forward by leaps and bounds, so that, every particle of the Medium remains in the device for almost the same time »

The invention also relates to a device for carrying out the described method. The device according to the invention consists of a first heat exchanger,

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one or more converter tubes, a second heat exchanger and a residence pipe, all of which are connected in series, furthermore from a device which supplies the polysaccharide medium with added liquefaction enzyme, by the aforementioned series connection under such a pressure presses that at the maximum temperature of the medium occurring in the second heat exchanger no steam formation takes place, and continues from one to the second heat exchanger connected device for cooling the medium to condensing temperature and for adding additional liquefying enzyme to the medium »

Further features of the invention emerge from the following description of the drawing and from the claims

In the drawing, two embodiments of the device according to the invention are shown schematically, and although shows

Pig. 1 shows a process tree of the first exemplary embodiment,
Pigβ 2 a cross section through a heat exchanger along the line AA in Pig. 1 and

Pig »3 shows a process tree of the second exemplary embodiment.

In the embodiment according to Pig »1, a container 1 contains a polysaccharide mediura, such as, for example, starch milk, to which a certain amount of liquefying enzyme is added has been. The addition of the enzyme to the starch medium

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can have taken place in the container 1 or even beforehand before the medium is introduced into the container 1 ”. From the bottom of the container 1 a conduit leads 2 to the input inlet side of a membrane pump 3 "", for example, a pump j whose membrane ₌ hydraulically by means of a back and forth reciprocating piston is actuated "The outlet side of the diaphragm pump 3 is connected to a pipe 4 located at which are connected in series with a first heat exchanger 5, a pipe converter 6, a second heat exchanger 7, a residence pipe 8, a cooler 9, a further pipe converter 10, a further cooler 11 and a pipe 12 with a back pressure valve 13

As can be seen from FIG. 2, there is the heat exchanger 5 from three tubes 14, 15 and 1.6 o arranged one inside the other. The tube 14 has a plurality of bends or bends and in this way forms between the tubes 14 and 15 slot-like passages 17 for the starch medium Furthermore, the heat exchanger 5 is designed so that Steam or other heating means into the interior of the inner tube 14 as well as into the heating jacket between the tubes 15 and 16 can be introduced «The steam is passed through a Pipe 18 is fed and the condensate and the exhaust steam are discharged through a pipe 19 (Fig. 1) ■ '· - The heat exchanger 7, the steam or some other heating medium through a pipe is supplied and from the condensate and exhaust steam through a Tube 21 can be withdrawn in a similar way to: heat exchanger 5 described above or else

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designed like an ordinary continuous heat exchanger be ο

While the starch medium flows through the retention tube 8, the temperature is maintained at which the medium has been heated in the heat exchanger 7 _0th In the cooler 9, the starch medium is cooled by a coolant which is fed to a cooling coil 22 through a pipe 23 and discharged again through a pipe 24. The cooler 11 consists of a cooling coil 25 with a supply line 26 and a discharge line 27. '"

The device according to Figo 3 corresponds, with the exception of deviations described below, the device according to Figo 1. The back pressure valve 13 is immediately behind arranged in the residence pipe 8 and an expansion cyclone 28 has taken the place of the cooler 9 in FIG. 1. The expansion cyclone 28 igt designed so that the aqueous starch medium can be subjected to a sudden pressure reduction to a portion of that contained in the medium To evaporate water «By setting the pressure in the cyclone accordingly, the one leaving the cyclone becomes The medium cooled to the desired temperature from the Steam withdrawn from the cyclone through a line 29 can be used, for example, to preheat the starch milk. A pump 30 is connected to the outlet side of the cyclone 28, which pumps the starch medium through the following Part of the device pressed

, - 11 -

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Follow the two directions. fig * 1 and 3 / have a tube 31 for ^; the supply of additional amounts of i

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The starch milk, der'ein.:. (Part of the total ^-for; amount vertierungsprozeß used to has been added "is in an rliytlimisch by the diaphragm pump 3 is vibrant Iließbewegung durc3i the is lärmeaustauscher 5 pressed ο During the-flow düroh the heat exchanger 5, the starch medium ! iron at a temperature of 20 to 60 ° G gradually "flüssigungstemperatur eriiitzt to the selected Yer, usually, in the ^loading: rich, is 80 ms 90 ° C ο This is temperature maintained while the starch medium subsequent Ronrkonverter 6 flows through, which may be isolated for yärmeidung an appreciable Tsmperaturabfalls suitably * the W g _e of the slit-like passages in the heat exchanger 5 is chosen so that the starch medium is! when flowing through dsr passages considerably "n shear exposed to a thixotropic Tiskositätsverminder- to produce the starch medium ». How he was _{refined 9} -sirdarch. the © influence ng of the liquid enzyme on the molecular chains; relieved

in the last ϊβάΐ ä & a \ ^ Wärmeatistausciiers 5 as well as la the Sonrkonverter 6 for a time from 2 * to _: § minutes has a Yorver liquefaction instead of g-ef and en, the heat medium is fed to the heat exchange.er T, internally it is at a temperature between 100 and heated to 160 ° C. These

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Temperature is in that. Retention tube 8 over a period of 3 to IG minutes maintained During this heat treatment, the crystalline T _e of the starch particles ile thermally decomposed, so that the liquefaction and saccharification enzymes enzymes can act on it in the subsequent treatment. Subject to this heating to a relatively high temperature, the starch medium is cooled in the cooler 9 to a temperature of about 80 to 90 ° C. and liquefying enzyme is pressed into the tube converter to, in which the final liquefaction takes place. This liquefaction is preferably carried out at a t _e mperature of 80 Ms 90 ° C over a period of 20 to 50 minutes'

Before the liquefied starch medium is saccharified, the starch medium is passed through the cooler 11, by cooling it to the optimum saccharification temperature, which is preferably in the range of 55 to 60 ° C · Then the starch medium is released through the back pressure valve 13 pressed into the drilling pipe 12 and from here fed to the saccharification container.

Instead of the cooler 11, in the device according to an expansion cyclone can be used in which at the same time a pressure reduction and a cooling of the starch medium can be carried out to the desired saccharification temperature

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In the device according to iig «3 the pressurized starch medium flows from the heat exchanger 7, in which it has been heated to a temperature of 100 to 160 ° C., through the residence pipe 8, in which the aforementioned temperature is maintained, to the expansion cyclone 28 »This cyclone is kept under vacuum so that the starch medium is cooled to a temperature of 80 to 90 ° C, which is the optimum temperature for the subsequent liquefaction in the converter 10. When the remaining amount of liquefying enzyme is added, the starch medium is pressed by the pump 30 through the high converter 1.0 to the cooler It, in which the temperature is lowered to the optimum saccharification temperature, i.e. to a temperature of 55 to 60 ° G the Stäfkeme- "could cause diums following the strong heat treatment declining operations in the converted product, preferably the product ufii quickly cooled"'-the' liquefaction enzyme immediately to the cooled medium added Therefore, "is particularly the apparatus of fig. ^3; b "It is preferable because the starch medium in the expansion cyclone is suddenly cooled ^{close to r.} ■ - '■ -' ■ ^s

The product from the devices according to Pig. 1 and 3-will finally for a period of 48 to 96 hours subjected to saccharification *

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Claims (1)

Pat e η t a η s ρ r ü c h / · 1 .. A process for the conversion of starch and other · poly saeehariden in dextrose and containing maltose products, wherein the polysaccharides are subjected to be converted first in a first process stage, an enzymatic liquefaction and then in a second process step to an enzymatic saccharification,! - characterized in that the liquefaction in the first procedural step is performed in such a way that the _f poly-saccharide medium to which a Verflüssigungse.nsym is added first forced through a first Wärmeaustauseher Dahei and heated without any entry of vapor on the condensing temperature is then passed through one or more converter tubes while maintaining essentially the same temperature, then passed through a second heat exchanger and heated to a temperature of well over 100 ° G and kept at this temperature and under a pressure for some time no steam Formation takes place and is then cooled to the liquefaction temperature and a further addition of liquefaction enzyme is given to complete the liquefaction of the medium. . 2. The method according to claim 1, characterized in that the 3141
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25.1ο.65 _M 809 811/0348 PolysaCGharid ^ edium in et out "only © ti
through, sudden passages ^ with. A bridge, speed, and speed is related to the seer's forces in the medium, a thixotropic viscosity comparison of the medium is generated. · · .-: ■ ^r:; - ^; .- ·· ■ -; - ·; ··: 3. Verfahr em = iaaeh i.nsprtieii 1 or 2, dadttreh gekenaseictoet, • -. ". That- the Polysaocharid-MedXTam-with eggiaer: p-ulsiereBd;; f ort- ■ schreiteüdeä Ströaiüngs'bewegungTang, / TaeispdeQkSweise. Lureh ' er— a MembraiifÖrderpTMpβ,. dttrGh \. v the Rohrkoinrerter tiaid- the second time Exchanger is led * Apparatus' for implementing ^ öös VerfahreBS maclä of claims & raieaustaus iron 1 Ms 3 _t characterized by eimeii first i Rather, a Eohrkomrerter with one or more Eonverterrohren, a second WärmeaustausGher and eiaaem retention tube, all in Eeihe. connected SINOE _r f'eraer g ISinriehtiin-through, which presses the PGljsaööharid-Mediiätt with zugesetateni Verflüs si gangs enzyme by the -rorgenaiinte Seihenschaltung under such a bridge, öaß OCE in the second heat exchanger to passing temperature of the medium germs vapor formation takes place ^ continue to a device for cooling connected to the second termexchange *; of; Sediiams at the liquid temperature and for the addition of further liquid enzymes to the edium, " ^Λ1 " 144226F 5. Apparatus according to claim 4, characterized in that the first heat exchanger with slot-like passages is of such a cross-section that "when the medium passes through the passages from the shear forces a thixotropic viscosity reduction in the medium of the medium is generated. 6. "Device according to claim 4 or 5 _? Characterized in that the device pressing the medium through the series connection is designed in such a way that it gives the medium a pulsating progressive flow movement. 809811/0348