CA1282778C - Non-hazing, low d.e. starch conversion syrups - Google Patents
Non-hazing, low d.e. starch conversion syrupsInfo
- Publication number
- CA1282778C CA1282778C CA000516430A CA516430A CA1282778C CA 1282778 C CA1282778 C CA 1282778C CA 000516430 A CA000516430 A CA 000516430A CA 516430 A CA516430 A CA 516430A CA 1282778 C CA1282778 C CA 1282778C
- Authority
- CA
- Canada
- Prior art keywords
- starch
- slurry
- hazing
- reaction zone
- liquid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Abstract
Abstract Starch conversion syrups of low D.E. values, known as malto-dextrins, are obtained by acid hydrolysis of a starch slurry. The process includes the steps of pass-ing a starch slurry having a mildly acidic pH of about 2 to 4 through a confined tubular preheat zone and trans-ferring heat to the slurry whereby it passes through a gelation stage and forms into a hot free flowing liquid having a temperature of at least 100°C and immediately forcing said hot liquid through a restrictive opening and into a confined tubular reaction zone accompanied by a sudden decrease in pressure whereby the starch is made highly susceptible to cleavage and continuously moving this starch liquid under mild hydrolyzing conditions through the tubular reaction zone to cause cleavage of linkages in the starch molecule to form relatively large molecular weight polysaccharides, but little or no mono and disaccharides, whereby a non-hazing fluid starch product is obtained having very low sweetness.
Description
~Z8Z77~3 Non-Hazing, Low D.E. Starch Conversion Syrups round of th_ Invention The prescnt invention relates to a process for the production of non-hazing starch conversion syrups having very low D.E. values. The term D.E. represents Dextrose Equivalent and refers to the reducing value of dissolved solids in a starch hydrolyzate expressed as percentage dextrose.
There is a large market for starch conversion syrups with bland taste and low sweetness at low D.E. value.
Such syrups are useful as basis for the preparation of food items as well as bodying agents and as additives having non-sweet: characteristics. As conversion o starch to syrups proceeds with lncreasing ~.E. values, the average molecular weight decreases and at the same time the solids leve], which is the ability of the syrup to contribute mouth appeal, chewiness and body decreases.
In many commercial applications, it is desirable to utilize a non-sweet starch conversion syrup which exhibits extreme clarity and which will not develop haze on stand-ing. While such non-hazing characteristics were readily imparted to starch conversion syrups having higher D.E.
values such as above about 20, it has been extremely difficult to produce low D.E. starch conversion syrups ~8Z7~
having non-hazing properties. Typically, starch conver-sion syrups having a ~.E. below about 15 were subject to haze development upon standing.
Attempts have been made to produce starch conversion syrups having even lower D.E. values which do not haze or form suspended matter upon standing. One such attempt to accomplish this is described in U.S. Patent 3,756,853 in which starch is first hydrolyzed to a D.E. of Erom about 20 to about 40 and thereafter the resulting starch con-version syrup was subjected to reverse osmosis until theD.E. of the syrup had been reduced to about 5 from about 18.
It is the object of the present invention to produce by a single acid hydrolysis step a starch conversion syrup lS having a very low D.E. value and which does not haze or form suspended matter upon standing.
Summary of the Invention According to the present invention an acidic starch feed slurry at a pH of about 2 to about 4 is passed through a confined tubu]ar preheat zone and heat is transerred to the slurry whereby it passes through a gelation stage and forms into a hot free flowing liquid having a temperature of at least 100C. This hot liquid is immediately forced through a restrictive opening and into a conined tuhular reaction zone ac:companied by a su~den decrease in pressure whereby the starch is made highly susceptible to cleavage.
This starch liquid is continuously moved under mild hydro-lyzing conditions through the tubular reaction zone to cause cleavage of linkages in the starch molecule to form relatively large molecular polysaccharides, but little or no mono and disaccharides whereby a non-hazing fluid starch product is obtained having a n.E. of less than about 20, preferably less than 5. It is even possible to obtain non-hazing fluid starch products having D.E. values of less than 1 and approaching 0, using the process of ~Z8Z7723 this invention.
The initial starch which is subjected to hydrolysis may be derived ~rom a wide variety of starch materials, e.g. corn, potato, tapioca, sago, rice, wheat, waxy maize, sorghum, etc. The starch may be used in refined form or as a natural component in cereal grains. To prepare a feedstock for the hydrolysis stage, the starch is formed into an aqueous slurry, having a solids content of less than about 50% by weight and preferably about 25 to 40%.
The pH of the starch slurry is adjusted to a mildly acidic range of about 2 to 4 by the addition of an acid, preferably hydrochloric acid. This mildly acidic starch slurry is then subjected to hydrolysis according to the above technique.
It is an important feature of this invention that formation of mono- and disaccharides be substantially avoided. This is accomplished by careful control of acidity, forcing the hot free flowing starch liquid through the restrictive opening before any D.E. value has been developed and then moving the hot starch liquid through the tubular reaction zone under mild hydrolysis conditions sufficient only to cause cleavage of linkages in the starch molecule to form relatively large molecular polysaccharides. The most lmportant condition ~or con-trol of the D.E. value i5 acidity and, ~or instance, ata suitable pH the residence time in the tubular reaction zone can vary quite widely without affecting D.E. The residence time in the tubular reaction zone does, however, affect the nature of the polysaccarides eormed. Typical residence times in the tubular reaction zone are less than ~ minutes, with total residence times in both the preheater and reaction zone being generally less than 10 minute~.
The temperature of the material passing through the restrictive opening must be above 100C and is usually 1282r77~3 below 170C. The pressure on the inlet side to the restrictive opening is usually at least 300 psi, with a pressure drop of at least 100 psi across the restrictive opening.
The products obtained from the hydrolysis of this invention are starch conversion syrups of very low ~.E.
values, other~Jise known as malto-dextrins, which exhi-bit excellent clarity and which do not develop haze upon standing. This has been achieved with syrups having D.E.
values of less than 1. Refining of the syrups can be carried out by conventional refining methods, such as treating with carbon, ion-exchange resins, filtration, centrifugation and the like.
Description of the Preferred Embodiments A preferred embodiment oE the reactor for carrying out this invention is described in the attached Figure 1.
As will be seen from Fig. 1, a holding tank 10 is pro-vided for a starch slurry feed. This tank has an outlet line 11 which feeds into a Moyno pump 12. The slurry is pumped out of pump 12 to line 13 at high pressure and into a heating coil 14. The pressure within coil 14 is control-led by varying the speed of pump 12.
The main reactor of this apparatus is a closed and insulated vessel 15 which is essentially a steam vessel being supplied by a steam inlet line 16 and a steam out-let line 17. A steam control valve 30 is pr~vided in the steam inlet line.
The tube 14 is made of stainless steel and is preEer-ably arranged as a coil. This is the preheater for the reaction and the slurry passing through tube 14 passes through a gel stage and forms into a hot free flowing liquid. The outlet of preheat tube 14 feeds into a first restrictive opening or oriice 18 having a much smaller diameter than the diameter of tube 14. The outlet of the orifice 18 connects to a further stainless steel tube 19 ~L28~778 which forms the tubular reaction zone of the invention.
This tube in the form of a coil passes back through the steam vessel 15 and the reaction occurs during the travel of the hot liquid through coil 19.
In order to control the pressure within coil 19, a second restrictive opening or orifice 20 is provided at the outlet. The reaction product is then collected through outlet line 21.
The following examples are further illustrative em-bodiments of this invention. All parts and proportions are by weight unless otherwise specified.
Example 1 (a) The process was carried out using a reactor of the type described in Fig. 1. The coils 14 and 19 were made from 1" O.D. stainless 3teel tubing with coil 14 having a length of 80 feet and coil 19 having a length of 200 feet. The first orifice had a diameter of 0.062 inch and the second orifice was in the form of a pair of adjacent openings, each having a diameter of 0.062 inch.
A starch slurry was formed from corn starch and water, this slurry containing 38% by weight of starch solids.
Hydrochloric acid was added to samples of the slurry to provide feedstocks of different acid levels.
These feedstocks were passed through the above reactor under the following conditions:
pH of Temp. at Inlet ~ess. Outlet press. Flow Rate Total D.E.
Slurry 1st. Orifice 1st. Ori~ice 1st. Orifice (G.P.M.) Time (C) (psi) ~si) (Sec) 2~55 150 850 150 0.94 550 3.5 2.50 147 800 120 0.94 550 7.3 2.45 148 800 110 0.95 538 10.0 ~282~78 Example 2 A series of further tests were carried out on the same reactor as used in Example 1, using a slurry of waxy maize starch as feedstock. Again the slurry contained 38% by weight of starch solids and hydrochloric acid was added to samples of the slurry to provide feedstocks of different acid levels.
These feedstocks were passed through the above reactor under the following conditions:
pH of Temp. at Inlet press. Outlet press. Flow Rate Total D.E
Slurry 1st. Orifice lst~ Orifice ]st. Orifice (G.P.M.) Time (C) (psi) ~si) (Sec) 3.4 131 900 130 0.57 905 0.2 3.1 128 900 120 0.73 706 1.6 2.7 120 880 120 0.99 518 3.2 2.6 115 800 150 1.15 450 8.1 2.6 117 800 130 1.01 513 3.3 2.6 118 800 145 1.03 500 8.0 ' ' ~8Z77~3 Examele 3 Malto-dextrins were produced using the same general type of reactor as in Example 1, but with only a single orifice at the tail end. The single orifice had a dia-meter of 0.101 inch.
The starch slurry was formed from corn starch and water and contained 39% by weight of starch solids. The acid was 30% HCl.
The p~ of the slurry and the D.E. values obtained were as follows:
Slurry pH D.E.
2.35 17.5 2.8 10.0 3.5 3.0 The three products obtained were spray dried into a white powder. When dissolved in water, these powders exhibited similar solubility and clarity properties commercial enzymatically produced malto-dextrins.
There is a large market for starch conversion syrups with bland taste and low sweetness at low D.E. value.
Such syrups are useful as basis for the preparation of food items as well as bodying agents and as additives having non-sweet: characteristics. As conversion o starch to syrups proceeds with lncreasing ~.E. values, the average molecular weight decreases and at the same time the solids leve], which is the ability of the syrup to contribute mouth appeal, chewiness and body decreases.
In many commercial applications, it is desirable to utilize a non-sweet starch conversion syrup which exhibits extreme clarity and which will not develop haze on stand-ing. While such non-hazing characteristics were readily imparted to starch conversion syrups having higher D.E.
values such as above about 20, it has been extremely difficult to produce low D.E. starch conversion syrups ~8Z7~
having non-hazing properties. Typically, starch conver-sion syrups having a ~.E. below about 15 were subject to haze development upon standing.
Attempts have been made to produce starch conversion syrups having even lower D.E. values which do not haze or form suspended matter upon standing. One such attempt to accomplish this is described in U.S. Patent 3,756,853 in which starch is first hydrolyzed to a D.E. of Erom about 20 to about 40 and thereafter the resulting starch con-version syrup was subjected to reverse osmosis until theD.E. of the syrup had been reduced to about 5 from about 18.
It is the object of the present invention to produce by a single acid hydrolysis step a starch conversion syrup lS having a very low D.E. value and which does not haze or form suspended matter upon standing.
Summary of the Invention According to the present invention an acidic starch feed slurry at a pH of about 2 to about 4 is passed through a confined tubu]ar preheat zone and heat is transerred to the slurry whereby it passes through a gelation stage and forms into a hot free flowing liquid having a temperature of at least 100C. This hot liquid is immediately forced through a restrictive opening and into a conined tuhular reaction zone ac:companied by a su~den decrease in pressure whereby the starch is made highly susceptible to cleavage.
This starch liquid is continuously moved under mild hydro-lyzing conditions through the tubular reaction zone to cause cleavage of linkages in the starch molecule to form relatively large molecular polysaccharides, but little or no mono and disaccharides whereby a non-hazing fluid starch product is obtained having a n.E. of less than about 20, preferably less than 5. It is even possible to obtain non-hazing fluid starch products having D.E. values of less than 1 and approaching 0, using the process of ~Z8Z7723 this invention.
The initial starch which is subjected to hydrolysis may be derived ~rom a wide variety of starch materials, e.g. corn, potato, tapioca, sago, rice, wheat, waxy maize, sorghum, etc. The starch may be used in refined form or as a natural component in cereal grains. To prepare a feedstock for the hydrolysis stage, the starch is formed into an aqueous slurry, having a solids content of less than about 50% by weight and preferably about 25 to 40%.
The pH of the starch slurry is adjusted to a mildly acidic range of about 2 to 4 by the addition of an acid, preferably hydrochloric acid. This mildly acidic starch slurry is then subjected to hydrolysis according to the above technique.
It is an important feature of this invention that formation of mono- and disaccharides be substantially avoided. This is accomplished by careful control of acidity, forcing the hot free flowing starch liquid through the restrictive opening before any D.E. value has been developed and then moving the hot starch liquid through the tubular reaction zone under mild hydrolysis conditions sufficient only to cause cleavage of linkages in the starch molecule to form relatively large molecular polysaccharides. The most lmportant condition ~or con-trol of the D.E. value i5 acidity and, ~or instance, ata suitable pH the residence time in the tubular reaction zone can vary quite widely without affecting D.E. The residence time in the tubular reaction zone does, however, affect the nature of the polysaccarides eormed. Typical residence times in the tubular reaction zone are less than ~ minutes, with total residence times in both the preheater and reaction zone being generally less than 10 minute~.
The temperature of the material passing through the restrictive opening must be above 100C and is usually 1282r77~3 below 170C. The pressure on the inlet side to the restrictive opening is usually at least 300 psi, with a pressure drop of at least 100 psi across the restrictive opening.
The products obtained from the hydrolysis of this invention are starch conversion syrups of very low ~.E.
values, other~Jise known as malto-dextrins, which exhi-bit excellent clarity and which do not develop haze upon standing. This has been achieved with syrups having D.E.
values of less than 1. Refining of the syrups can be carried out by conventional refining methods, such as treating with carbon, ion-exchange resins, filtration, centrifugation and the like.
Description of the Preferred Embodiments A preferred embodiment oE the reactor for carrying out this invention is described in the attached Figure 1.
As will be seen from Fig. 1, a holding tank 10 is pro-vided for a starch slurry feed. This tank has an outlet line 11 which feeds into a Moyno pump 12. The slurry is pumped out of pump 12 to line 13 at high pressure and into a heating coil 14. The pressure within coil 14 is control-led by varying the speed of pump 12.
The main reactor of this apparatus is a closed and insulated vessel 15 which is essentially a steam vessel being supplied by a steam inlet line 16 and a steam out-let line 17. A steam control valve 30 is pr~vided in the steam inlet line.
The tube 14 is made of stainless steel and is preEer-ably arranged as a coil. This is the preheater for the reaction and the slurry passing through tube 14 passes through a gel stage and forms into a hot free flowing liquid. The outlet of preheat tube 14 feeds into a first restrictive opening or oriice 18 having a much smaller diameter than the diameter of tube 14. The outlet of the orifice 18 connects to a further stainless steel tube 19 ~L28~778 which forms the tubular reaction zone of the invention.
This tube in the form of a coil passes back through the steam vessel 15 and the reaction occurs during the travel of the hot liquid through coil 19.
In order to control the pressure within coil 19, a second restrictive opening or orifice 20 is provided at the outlet. The reaction product is then collected through outlet line 21.
The following examples are further illustrative em-bodiments of this invention. All parts and proportions are by weight unless otherwise specified.
Example 1 (a) The process was carried out using a reactor of the type described in Fig. 1. The coils 14 and 19 were made from 1" O.D. stainless 3teel tubing with coil 14 having a length of 80 feet and coil 19 having a length of 200 feet. The first orifice had a diameter of 0.062 inch and the second orifice was in the form of a pair of adjacent openings, each having a diameter of 0.062 inch.
A starch slurry was formed from corn starch and water, this slurry containing 38% by weight of starch solids.
Hydrochloric acid was added to samples of the slurry to provide feedstocks of different acid levels.
These feedstocks were passed through the above reactor under the following conditions:
pH of Temp. at Inlet ~ess. Outlet press. Flow Rate Total D.E.
Slurry 1st. Orifice 1st. Ori~ice 1st. Orifice (G.P.M.) Time (C) (psi) ~si) (Sec) 2~55 150 850 150 0.94 550 3.5 2.50 147 800 120 0.94 550 7.3 2.45 148 800 110 0.95 538 10.0 ~282~78 Example 2 A series of further tests were carried out on the same reactor as used in Example 1, using a slurry of waxy maize starch as feedstock. Again the slurry contained 38% by weight of starch solids and hydrochloric acid was added to samples of the slurry to provide feedstocks of different acid levels.
These feedstocks were passed through the above reactor under the following conditions:
pH of Temp. at Inlet press. Outlet press. Flow Rate Total D.E
Slurry 1st. Orifice lst~ Orifice ]st. Orifice (G.P.M.) Time (C) (psi) ~si) (Sec) 3.4 131 900 130 0.57 905 0.2 3.1 128 900 120 0.73 706 1.6 2.7 120 880 120 0.99 518 3.2 2.6 115 800 150 1.15 450 8.1 2.6 117 800 130 1.01 513 3.3 2.6 118 800 145 1.03 500 8.0 ' ' ~8Z77~3 Examele 3 Malto-dextrins were produced using the same general type of reactor as in Example 1, but with only a single orifice at the tail end. The single orifice had a dia-meter of 0.101 inch.
The starch slurry was formed from corn starch and water and contained 39% by weight of starch solids. The acid was 30% HCl.
The p~ of the slurry and the D.E. values obtained were as follows:
Slurry pH D.E.
2.35 17.5 2.8 10.0 3.5 3.0 The three products obtained were spray dried into a white powder. When dissolved in water, these powders exhibited similar solubility and clarity properties commercial enzymatically produced malto-dextrins.
Claims (5)
1. A process for producing a non-hazing starch conversion syrup having a D.E. of from about 0 to about 20, which comprises passing a starch slurry having a mildly acidic pH of about 2 to 4 through a confined tubular preheat zone and transferring heat to the slurry whereby it passes through a gelation stage and forms into a hot free flow-ing liquid having a temperature of at least 100°C and immediately forcing said hot liquid through a restrictive opening and into a confined tubular reaction zone accom-panied by a sudden decrease in pressure whereby the starch is made highly susceptible to, cleavage and continuously moving this starch liquid under mild hydrolyzing condi-tions through the tubular reaction zone to cause cleavage of linkages in the starch molecule to form relatively large molecular weight polysaccharides, but little or no mono and disaccharides, whereby a non-hazing fluid starch product is obtained having very low sweetness.
2. A process according to claim 1 wherein the starch is corn or waxy maize.
3. A process according to claim 1 wherein the starch slurry contains less than 50% by weight of starch solids.
4. A process according to claim 3 wherein the starch slurry contains about 25 to 40% by weight of starch solids.
5. A process according to claim 1 wherein the fluid pressure on the inlet side of the restrictive opening is at least 300 psi and the pressure drop across the restrictive opening is at least 100 psi.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000516430A CA1282778C (en) | 1986-08-20 | 1986-08-20 | Non-hazing, low d.e. starch conversion syrups |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000516430A CA1282778C (en) | 1986-08-20 | 1986-08-20 | Non-hazing, low d.e. starch conversion syrups |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1282778C true CA1282778C (en) | 1991-04-09 |
Family
ID=4133767
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000516430A Expired - Fee Related CA1282778C (en) | 1986-08-20 | 1986-08-20 | Non-hazing, low d.e. starch conversion syrups |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1282778C (en) |
-
1986
- 1986-08-20 CA CA000516430A patent/CA1282778C/en not_active Expired - Fee Related
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| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |