Purification and production method of glucose syrup

Abstract

The invention belongs to the technical field of light industry and chemical engineering biotechnology, and particularly relates to a purification and production method of glucose syrup. The glucose syrup which is high in boiling temperature and high in purification is prepared through the steps of starch blending, low-pH liquefaction, multistage protein removal, low-conductivity preparation, high-glucose concentration, low-foam preparation and the like. In the liquefaction process, a low-pH enzyme preparation is adopted for liquefaction treatment, the glucose content can be increased, chemicals are saved, and the yield is increased; the two-stage compartment type constant-pressure separator is adopted for cyclic separation, and the macroporous resin is used for performing multi-stage removal on the protein, so that the lowest protein content in the sugar liquid can be ensured. And the electrodialysis separation subsystem is adopted for low-conductivity preparation, so that the conductivity of the sugar liquid is reduced to 20 [mu] S / cm or below. The edible soybean oil is fed into the syrup, so that the temperature resistance of the syrup can be effectively improved to 130 DEG C or above, and the syrup has less foam and does not boil.

Description

Technical Field

[0001] The invention belongs to the technical field of light industry and chemical industry biotechnology, and specifically relates to a method for purifying and producing glucose syrup. Background Art

[0002] Starch syrup is becoming more and more popular among consumers due to its pure taste, good storage and moderate price. Among them, glucose syrup prepared from starch is widely used in soft candy, cakes and other foods. However, in the production process of glucose syrup, due to the characteristics of the sugar solution and the residual ions and proteins in the sugar solution, it is very easy to cause excessive foam and poor temperature resistance, thus affecting the use of glucose syrup. Summary of the invention

[0003] In view of the above situation, the technical problem to be solved by the present invention is how to provide a more efficient and purer method for purifying and producing glucose syrup, which can better improve the quality of syrup and increase the yield of syrup.

[0004] The purpose of the first aspect of the present invention is to provide a method for purifying and producing glucose syrup, comprising:

[0005] 1) Low pH liquefaction: adjusting the pH of the starch slurry to 4.0-5.5, adding a low pH liquefaction enzyme to liquefy, and obtaining a liquefied liquid;

[0006] 2) Saccharification: adding saccharifying enzyme to the liquefied liquid obtained in step 1) to perform saccharification to obtain saccharified liquid;

[0007] 3) Removing protein: separating, filtering and chromatography the saccharified liquid obtained in step 2) to reduce the protein content to ≤0.1% to obtain a low-protein sugar liquid;

[0008] 4) Removing ions: Using an electrodialysis deionization system to remove ions from the low-protein sugar solution obtained in step 3) to obtain a low-conductivity sugar solution;

[0009] 5) Concentration: Concentrating the low-conductivity sugar solution obtained in step 4) to a concentration of 40-65% to obtain a concentrated syrup;

[0010] 6) Low foam treatment: Add edible oil to the concentrated syrup obtained in step 5) to obtain.

[0011] Preferably, in step 1), the starch slurry is selected from corn starch slurry;

[0012] Preferably, the concentration of the starch slurry is 10°Be′ to 25°Be′.

[0013] Preferably, in step 1), the pH of the starch slurry is adjusted to 4.2 to 5.2; more preferably 4.4 to 5.0; and even more preferably 4.5 to 4.8.

[0014] Preferably, the conditional pH is carried out by an acidic solution, and the acidic solution includes at least one of a recovered acid solution, a hydrochloric acid solution, a nitric acid solution or a sulfuric acid solution; more preferably, the volume concentration of the acidic solution is 3-5%.

[0015] Preferably, in step 1), the concentration of the starch slurry is 18°Be′~24°Be′; more preferably, it is 16°Be′~22°Be′; and even more preferably, it is 14°Be′~20°Be′.

[0016] In some embodiments of the present invention, corn starch and water are slurried in a ratio of 1:1.2-1.5, the slurry water temperature is ≤66°C, and the slurry is finally adjusted to 14°Be′-20°Be′.

[0017] Preferably, in step 1), the DE value of the liquefied liquid is 10-30; more preferably 15-27; and even more preferably 18-25.

[0018] Preferably, the dosage of the low pH liquefaction enzyme is 42-64 U / g dry starch.

[0019] Preferably, the liquefaction temperature is 100-140°C; more preferably 105-120°C; further preferably 110-115°C.

[0020] Preferably, the liquefaction time is 1 to 3 hours; more preferably 1.5 to 2.5 hours; further preferably 2.0 to 2.5 hours.

[0021] Preferably, the low pH liquefaction enzyme is selected from Novozymes LpHera enzyme preparation.

[0022] Preferably, the low pH liquefaction enzyme is added in two portions.

[0023] In a specific embodiment of the present invention, there is a flash evaporation step between the two enzyme additions. Specifically, the pH of the slurry is adjusted to 4.5-4.8 with a 4% concentration of dilute acid, and a low-pH liquefying enzyme is added, followed by spraying at a spraying temperature of 110°C-115°C, a steam pressure of more than 3.5 bar, and a serpentine pressure difference of more than 0.7 bar. After the flash evaporation is completed, the low-pH liquefying enzyme is added, and the laminar flow column is maintained for 2.0h-2.5h, and the final DE value reaches 18-25.

[0024] In some embodiments of the present invention, the first enzyme addition uses Novozymes LpHera enzyme preparation at 0.06L / ton powder to 0.1L / ton powder, and the second enzyme addition uses Novozymes LpHera enzyme preparation at 0.15L / ton powder to 0.22L / ton powder.

[0025] Preferably, in step 2), the amount of the saccharifying enzyme is 30-53 U / g of dry starch glucoamylase and 0.64-1.15 U / g of dry starch pullulanase. Preferably, the saccharification temperature is 50°C to 70°C; more preferably 53°C to 68°C; and even more preferably 56°C to 66°C.

[0026] Preferably, the saccharification time is greater than 20 h; more preferably, greater than 25 h; and even more preferably, greater than 30 h.

[0027] Preferably, the saccharifying enzyme is selected from the Mchao type II complex saccharifying enzyme.

[0028] Preferably, the glucose content of the saccharified liquid is ≥90%; more preferably, it is ≥92%; and even more preferably, it is ≥95%.

[0029] Preferably, the separation and filtration method in step 3) includes primary separation and secondary separation.

[0030] Preferably, the primary separation adopts a chamber-type constant pressure separator for cyclic separation treatment.

[0031] Preferably, the secondary separation adopts a chamber-type constant pressure separator for cyclic separation treatment.

[0032] Preferably, the chromatography is performed using a deproteinized resin.

[0033] Preferably, the deproteinization resin comprises a macroporous adsorption resin.

[0034] In some embodiments of the present invention, the constant pressure of the first-stage chamber constant pressure separator is 2.5 bar, and the separation speed is 23 m / s. 3 / h, the cycle time is 1.0h; the constant pressure of the two-stage box constant pressure separator is 4bar, and the separation speed is 12m 3 / h, cycle time is 0.75h.

[0035] Preferably, after the deproteinization resin is treated, the deproteinization resin is cleaned with an alkali solution and regenerated with an acid solution.

[0036] Preferably, the regenerated acid solution is recovered, and the recovered acid solution is used for adjusting the pH of the starch slurry in step 1).

[0037] Preferably, the alkali solution comprises at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, sodium hydroxide or potassium bicarbonate solution.

[0038] Preferably, the concentration of the alkaline compound in the alkali solution is preferably 3 to 5 wt %.

[0039] Preferably, the acid solution includes at least one of a hydrochloric acid solution, a nitric acid solution or a sulfuric acid solution.

[0040] Preferably, the concentration of the acidic compound in the acid solution is preferably 3-5 wt %.

[0041] In some embodiments of the present invention, after the deproteinized macroporous resin is saturated with adsorption for a long time, 0.5 m 3 ~1.0m 3 3% to 5% dilute alkali solution for cleaning, and then use 0.5m 3 ~1.0m 3 Regeneration treatment with 3% to 5% dilute hydrochloric acid.

[0042] Preferably, in step 4), the conductivity of the low-conductivity sugar solution is <20 μS / cm.

[0043] Preferably, the light transmittance of the low-conductivity sugar solution is >98%.

[0044] Preferably, in step 5), the concentration is performed by high temperature reverse osmosis;

[0045] Preferably, the temperature of the high-temperature reverse osmosis is 45-65°C; more preferably 47-60°C; further preferably 50-55°C.

[0046] Preferably, the concentration pressure of the high-temperature reverse osmosis is 6-10 MPa, and the pH is 4.0-6.0.

[0047] Preferably, the concentration of the concentrated syrup is 45-60wt%; more preferably, it is 50-55wt%.

[0048] Preferably, the step of cooling the mixture after concentration is further included; the cooling step is to 25-44°C; more preferably to 30-42°C; and even more preferably to 32-40°C.

[0049] Preferably, in step 6), the edible oil includes at least one of soybean oil, peanut oil, corn oil and rapeseed oil; more preferably soybean oil; and even more preferably first-grade soybean oil.

[0050] Preferably, the edible oil is added in an amount of 20 to 50 mL per ton of syrup.

[0051] The second aspect of the present invention provides the application of the preparation method of the first aspect of the present invention in the field of food and fermentation.

[0052] The beneficial effects of the present invention are:

[0053] The invention prepares a high-boiling-temperature and highly purified glucose syrup through the steps of starch blending, low-pH liquefaction, multi-stage protein removal, low-conductivity preparation, high-glucose concentration, low-foam preparation and the like, and the syrup has less foam and does not boil.

[0054] Specifically, compared with the prior art, the present invention has the following advantages:

[0055] (1) In the liquefaction process, a low pH of 4.5 to 4.8 is used for liquefaction, and there is no need to add too much alkali solution to adjust the pH during the slurry adjustment process. Adding too much alkali solution during slurry adjustment will cause the slurry to be turbid and produce an alkaline taste, resulting in poor liquefaction effect. This process uses a low pH of 4.5 to 4.8 for liquefaction, which greatly reduces the addition of alkali solution, making the slurry clearer and not producing an alkaline taste, effectively improving the liquefaction effect. In the traditional slurry adjustment process, after adding alkali solution to adjust the pH, the pH will gradually decrease with the increase of time. The low pH liquefaction of the present invention does not need to continuously add alkali solution to prevent pH changes during the entire liquefaction process, which helps to achieve a long-tail effect of good liquefaction effect.

[0056] (2) During the enzymatic hydrolysis process, the enzyme preparation added is a low-pH liquefaction enzyme, which can effectively increase the glucose content and save the cost of pH adjustment chemicals. Compared with traditional α-amylase, low-pH liquefaction enzyme has a unique starch hydrolysis method. Only a small amount of panose precursor is produced during the hydrolysis process. Therefore, it can produce more glucose and less panose, thereby increasing the starch yield. Since low pH is used for liquefaction, less chemicals are used to adjust the pH and reduce the ion content in the sugar solution. During the refining process of the electrodialysis desorption system, the load of the desorption system can be reduced, the product quality can be improved, the refining efficiency can be improved, the life of the electrodialysis system can be extended, and costs can be saved.

[0057] (3) In the protein removal step, first use a first-stage chamber constant pressure separator for circulation separation to remove sugar residues in the sugar solution, and then the sugar solution enters a second-stage chamber constant pressure separator for circulation separation to further remove protein, fine residues and other impurities in the sugar solution. After liquefaction and saccharification and hydrolysis for more than 30 hours, insoluble sugar residues and proteins will gradually form in the sugar solution. First use a first-stage chamber constant pressure separator for circulation separation, the pressure is controlled at 1.8 bar to 3.0 bar, and the circulation flow rate is controlled at 20m 3 / h~26m 3 / h, the cycle time is controlled at 0.5h~1.5h, which can effectively remove the sugar residue in the sugar solution. Then use the two-stage box constant pressure separator, the constant pressure is controlled at 3.0~4.5bar, and the circulation flow rate is controlled at 8m 3 / h~15m 3 / h, the cycle time is controlled at 0.5h~1.0h, and impurities such as protein and fine residue in the sugar solution are further removed. After two-stage constant pressure separation, a small amount of soluble protein will still remain in the sugar solution, which cannot be removed by separation. At this time, it is adsorbed by macroporous resin. The strong adsorption of macroporous resin can effectively remove the residual protein, thereby reducing the protein content to ≤0.1%.

[0058] (4) In the low-foam preparation process, the present invention reduces the conductivity of the syrup to less than 20 μS / cm and the transmittance to more than 98% through the electrodialysis deionization system, and the syrup has a high degree of purification and less foam. At the same time, the first-class edible soybean oil is added to the syrup in an amount of 26 ml to 40 ml per ton of sugar, which can not only enrich the nutritional elements of the syrup, but also further improve the temperature resistance of the sugar solution to more than 130°C. During the processing, it can effectively ensure that the sugar solution does not boil and low foam is generated.

[0059] (5) In the high glucose concentration process, the present invention does not use the traditional evaporation method for concentration, but uses high-temperature reverse osmosis to concentrate the sugar solution. Traditional evaporation concentration uses four-effect or MVR evaporators to evaporate the sugar solution. Due to the forced circulation of the circulation pump and the sugar film formed inside the evaporator, a large amount of foam will be generated during the evaporation process, and a burnt smell will also be produced (especially for glucose, which will be more serious). Too much foam not only affects the use, but also affects the solubility of the syrup, causing processing difficulties. In order to avoid the above problems, the present invention first uses hot water to heat the glucose solution to 50°C to 55°C, thereby reducing the viscosity of the sugar solution, and then uses reverse osmosis for concentration. No foam and burnt smell will be generated, thereby improving the solubility of the syrup. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 The present invention is a schematic diagram of the process of purifying and producing glucose syrup. DETAILED DESCRIPTION

[0061] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0062] Example 1 A method for purifying and producing glucose syrup

[0063] A method for purifying and producing glucose syrup comprises the following steps:

[0064] (1) Mixing: Mix corn starch and water in a ratio of 1:1.2, set the water temperature at 66°C, and add water to adjust to 14°Be′.

[0065] (2) Low pH liquefaction: Use 4% dilute acid to adjust the pH of the slurry to 4.5, add Novozymes low pH liquefaction enzyme at a ratio of 0.06L / ton starch, and then spray at a spray temperature of 111°C, a steam pressure of 3.5bar, and a serpentine pressure difference of 0.7bar. After the flash evaporation is completed, Novozymes low pH liquefaction enzyme is added at a rate of 0.15L / ton starch. Enter the laminar flow column and maintain for 2.0h. The liquefied material has a DE value of 18.

[0066] (3) Saccharification: Cool the liquefied liquid to 56°C and add 107 mL / min of composite saccharifying enzyme. 3 After saccharification for 30 hours, the glucose content increased to 95.3%.

[0067] (4) Multi-stage protein removal: The saccharification liquid enters the first-stage chamber constant pressure separator for circulation separation to remove the sugar residue in the sugar liquid. The chamber constant pressure separator has a constant pressure of 1.8 bar and a circulation flow rate of 20 m / s. 3 / h, and the circulation time is 1.5bar. Then the sugar solution enters the secondary box-type constant pressure separator to remove impurities such as protein in the sugar solution. The constant pressure of the box-type constant pressure separator is set at 4.5bar, and the circulation flow rate is set at 8m 3 / h, the cycle time is 0.5h. After two-stage separation, the protein content in the sugar solution is reduced to 2.2%, and the light transmittance of the sugar solution discharged from the separator is 97.2%. The sugar solution then enters the protein removal macroporous resin to further remove the residual protein in the sugar solution. After the protein is removed by the macroporous resin, the protein content in the sugar solution is reduced to 0.09%, the light transmittance is 97.5%, and the conductivity is 35μs / cm.

[0068] After the protein removal macroporous resin is saturated with adsorption for a long time, 0.5 m 3 5% diluted alkali solution for cleaning, and then use 0.5m 3 Regeneration treatment with 5% dilute hydrochloric acid.

[0069] (5) Low conductivity preparation: The sugar solution is cooled to 45°C using low temperature water and then enters the electrodialysis deionization system for refining. The conductivity of the sugar solution is 18 μs / cm and the transmittance is 98.3%.

[0070] (6) High glucose concentration: The sugar solution is heated to 50°C and then enters the reverse osmosis membrane for concentration treatment. The reverse osmosis membrane concentration pressure is controlled to 8MPa and the reverse osmosis operating temperature is 50°C. The sugar solution discharge concentration is controlled at 53%, the pH is controlled to 4.2, and the discharge temperature is reduced to 40°C.

[0071] (7) Low foam preparation: First-grade soybean oil was added to the concentrated high-glucose syrup at a rate of 26 mL per ton of sugar. The syrup was boiled and tested, and the temperature resistance of the syrup reached 130°C. 200 mL of the syrup was placed in a beaker and boiled. There was little foam during the boiling process, and the maximum height of the foam was 100 mL.

[0072] Example 2 A method for purifying and producing glucose syrup

[0073] A method for purifying and producing glucose syrup comprises the following steps:

[0074] (1) Mixing: Mix corn starch and water in a ratio of 1:1.4, set the water temperature at 64°C, and add water to adjust to 17°Be′.

[0075] (2) Low pH liquefaction: Use 4% dilute acid to adjust the pH of the slurry to 4.6, add Novozymes low pH liquefaction enzyme at a ratio of 0.07L / ton starch, and then spray at a spray temperature of 113°C, a steam pressure of 3.9 bar, and a serpentine pressure difference of 0.9 bar. After the flash evaporation is completed, Novozymes low pH liquefaction enzyme is added at a rate of 0.19L / ton starch. Enter the laminar flow column and maintain for 2.3 hours. The liquefied material has a DE value of 21.

[0076] (3) Saccharification: Cool the liquefied liquid to 60°C and add 112 mL / min of composite saccharifying enzyme. 3 After saccharification for 35 hours, the glucose content increased to 95.8%.

[0077] (4) Multi-stage protein removal: The saccharification liquid enters the first-stage chamber constant pressure separator for circulation separation to remove the sugar residue in the sugar liquid. The chamber constant pressure separator has a constant pressure of 2.5 bar and a circulation flow rate of 23 m / s. 3 / h, and the circulation time is 1.0 bar. Then the sugar solution enters the secondary box-type constant pressure separator to remove impurities such as protein in the sugar solution. The constant pressure of the box-type constant pressure separator is set at 4.0 bar, and the circulation flow rate is set at 12m 3 / h, the cycle time is 0.75h. After two-stage separation, the protein content in the sugar solution is reduced to 1.5%, and the light transmittance of the sugar solution discharged from the separator is 97.7%. The sugar solution then enters the protein removal macroporous resin to further remove the residual protein in the sugar solution. After the protein is removed by the macroporous resin, the protein content in the sugar solution is reduced to 0.06%, the light transmittance is 98.3%, and the conductivity is 31μs / cm.

[0078] After the protein removal macroporous resin is saturated with adsorption for a long time, 0.7m 3 4% diluted alkali solution for cleaning, and then use 0.8m 3 Regeneration treatment with 4% dilute hydrochloric acid.

[0079] (5) Low conductivity preparation: The sugar solution is cooled to 34°C using low temperature water and then enters the electrodialysis deionization system for refining. The conductivity of the sugar solution is 13 μs / cm and the transmittance is 99.4%.

[0080] (6) High glucose concentration: The sugar solution is heated to 53°C and then enters the reverse osmosis membrane for concentration treatment. The reverse osmosis membrane concentration pressure is controlled to 8MPa and the reverse osmosis operating temperature is 53°C. The sugar solution discharge concentration is controlled at 52%, the pH is controlled to 5.1, and the discharge temperature is reduced to 35°C.

[0081] (7) Low foam preparation: First-grade soybean oil was added to the concentrated high-glucose syrup at a rate of 32 mL per ton of sugar. The syrup was boiled and tested, and the temperature resistance of the syrup reached 134°C. 200 mL of the syrup was placed in a beaker and boiled. There was little foam during the boiling process, and the maximum foam rise height was 88 mL.

[0082] Example 3

[0083] A method for purifying and producing glucose syrup comprises the following steps:

[0084] (1) Mixing: Mix corn starch and water in a ratio of 1:1.5, set the water temperature at 61°C, and add water to adjust to 21°Be′.

[0085] (2) Low pH liquefaction: Use 4% dilute acid to adjust the pH of the slurry to 4.8, add Novozymes low pH liquefaction enzyme at a ratio of 0.1L / ton starch, and then spray at a spray temperature of 117°C, a steam pressure of 4.2bar, and a serpentine pressure difference of 1.0bar. After the flash evaporation is completed, Novozymes low pH liquefaction enzyme is added at a rate of 0.22L / ton starch. Enter the laminar flow column and maintain for 2.5h. The liquefied material has a DE value of 24.

[0086] (3) Saccharification: Cool the liquefied liquid to 66°C and add 120 mL / min of composite saccharifying enzyme. 3 After saccharification for 38 hours, the glucose content increased to 96.3%.

[0087] (4) Multi-stage protein removal: The saccharification liquid enters the first-stage chamber constant pressure separator for circulation separation to remove the sugar residue in the sugar liquid. The chamber constant pressure separator has a constant pressure of 3.0 bar and a circulation flow rate of 26 m / s. 3 / h, and the circulation time is 0.5bar. Then the sugar solution enters the secondary box-type constant pressure separator to remove impurities such as protein in the sugar solution. The constant pressure of the box-type constant pressure separator is set at 3.0bar, and the circulation flow rate is set at 15m 3 / h, the cycle time is 1.0h. After two-stage separation, the protein content in the sugar solution is reduced to 1.9%, and the light transmittance of the sugar solution discharged from the separator is 97.5%. The sugar solution then enters the protein removal macroporous resin to further remove the residual protein in the sugar solution. After the protein is removed by the macroporous resin, the protein content in the sugar solution is reduced to 0.07%, the light transmittance is 98.1%, and the conductivity is 34μs / cm.

[0088] After the protein removal macroporous resin is saturated with adsorption for a long time, 1.0 m 3 3% diluted alkali solution for cleaning, and then use 1.0m 3 Regeneration treatment with 3% dilute hydrochloric acid.

[0089] (5) Low conductivity preparation: The sugar solution is cooled to 30°C using low temperature water and then enters the electrodialysis deionization system for refining. The conductivity of the sugar solution is 16 μs / cm and the transmittance is 98.8%.

[0090] (6) High glucose concentration: The sugar solution is heated to 55°C and then enters the reverse osmosis membrane for concentration treatment. The reverse osmosis membrane concentration pressure is controlled to 8MPa and the reverse osmosis operating temperature is 55°C. The sugar solution discharge concentration is controlled at 57%, the pH is controlled to 6.0, and the discharge temperature is reduced to 32°C.

[0091] (7) Low foam preparation: First-grade soybean oil was added to the concentrated high-glucose syrup at a rate of 40 mL per ton of sugar. The syrup was boiled and tested, and the temperature resistance of the syrup reached 141°C. 200 mL of the syrup was placed in a beaker and boiled. There was little foam during the boiling process, and the maximum foam rise height was 83 mL.

[0092] Comparative Example 1

[0093] (1) Mixing: Mix corn starch and water in a ratio of 1:1.2, set the water temperature at 65°C, and finally mix the slurry to 15°Be′.

[0094] (2) Liquefaction: Add 4% dilute caustic soda to the slurry to adjust the pH value of the slurry to 5.6, add high-temperature amylase at a rate of 0.08 L / t of powder, and spray at a spray temperature of 111°C, a steam pressure of 3.6 bar, and a serpentine pressure difference of 0.7 bar. After flash evaporation, add high-temperature amylase at a rate of 0.18 L / t of powder, and then enter the laminar flow column for 2.0 h. The liquefied material DE value is detected to be 16.

[0095] (3) Saccharification: Cool the liquefied liquid to 55°C and add 107 mL / min of composite saccharifying enzyme. 3 After saccharification for 30 hours, the glucose content was detected to be 95.0%.

[0096] (4) Multi-stage protein removal: The saccharification liquid enters the first-stage chamber constant pressure separator for circulation separation to remove the sugar residue in the sugar liquid. The chamber constant pressure separator has a constant pressure of 1.8 bar and a circulation flow rate of 20 m / s. 3 / h, and the circulation time is 1.5bar. Then the sugar solution enters the secondary box-type constant pressure separator to remove impurities such as protein in the sugar solution. The constant pressure of the box-type constant pressure separator is set at 4.5bar, and the circulation flow rate is set at 8m 3 / h, the cycle time is 0.5h. After two-stage separation, the protein content in the sugar solution was detected to be 2.4%, and the light transmittance of the sugar solution discharged from the separator was 96.9%. The sugar solution then entered the protein removal macroporous resin to further remove the residual protein in the sugar solution. After the protein was removed by the macroporous resin, the protein content in the sugar solution was reduced to 0.13%, the light transmittance was 97.2%, and the conductivity was 42μs / cm.

[0097] (5) Deionization preparation: The sugar solution was cooled to 43°C using low-temperature water and then put into the electrodialysis deionization system for refining. The conductivity of the sugar solution was 23 μs / cm and the transmittance was 97.6%.

[0098] Comparative Example 2

[0099] (1) Mixing: Mix corn starch and water in a ratio of 1:1.4, set the water temperature at 63°C, and add water to adjust to 16°Be′.

[0100] (2) Low pH liquefaction: Use 4% dilute acid to adjust the pH of the slurry to 4.5, add Novozymes low pH liquefaction enzyme at a ratio of 0.07L / ton starch, and then spray at a spray temperature of 113°C, a steam pressure of 3.8bar, and a serpentine pressure difference of 0.9bar. After the flash evaporation is completed, Novozymes low pH liquefaction enzyme is added at a rate of 0.19L / ton starch. Enter the laminar flow column and maintain for 2.3h. The liquefied material has a DE value of 20.

[0101] (3) Saccharification: Cool the liquefied liquid to 59°C and add 112 mL / min of composite saccharifying enzyme. 3 After saccharification for 35 hours, the glucose content increased to 95.7%.

[0102] (4) Multi-stage protein removal: The saccharification liquid enters the first-stage chamber constant pressure separator for circulation separation to remove the sugar residue in the sugar liquid. The chamber constant pressure separator has a constant pressure of 2.5 bar and a circulation flow rate of 23 m / s. 3 / h, and the circulation time is 1.0 bar. Then the sugar solution enters the secondary box-type constant pressure separator to remove impurities such as protein in the sugar solution. The constant pressure of the box-type constant pressure separator is set at 4.0 bar, and the circulation flow rate is set at 12m 3 / h, the cycle time is 0.75h. After two-stage separation, the protein content in the sugar solution is reduced to 1.6%, and the light transmittance of the sugar solution discharged from the separator is 97.5%. The sugar solution then enters the protein removal macroporous resin to further remove the residual protein in the sugar solution. After the protein is removed by the macroporous resin, the protein content in the sugar solution is reduced to 0.07%, the light transmittance is 98.0%, and the conductivity is 44μs / cm.

[0103] After the protein removal macroporous resin is saturated with adsorption for a long time, 0.7m 3 4% diluted alkali solution for cleaning, and then use 0.8m 3 Regeneration treatment with 4% dilute hydrochloric acid.

[0104] (5) Deionization preparation: The sugar solution was cooled to 33°C using low-temperature water and then put into the electrodialysis deionization system for refining. The conductivity of the sugar solution was 27 μs / cm and the transmittance was 97.8%. At the same time, the operation time of the deionization system from the start of sugar passing to system saturation was counted.

[0105] (6) High glucose concentration: The sugar solution is heated to 52°C and then enters the reverse osmosis membrane for concentration treatment. The reverse osmosis membrane concentration pressure is controlled to 8MPa and the reverse osmosis operating temperature is 52°C. The sugar solution discharge concentration is controlled at 52%, the pH is controlled to 5.0, and the discharge temperature is reduced to 34°C.

[0106] (7) Low foam preparation: First-grade soybean oil was added to the concentrated high-glucose syrup at a rate of 32 mL per ton of sugar. The syrup was boiled and tested, and the temperature resistance of the syrup was 125°C.

[0107] Comparative Example 3

[0108] (1) Mixing: Mix corn starch and water in a ratio of 1:1.3, set the water temperature at 63°C, and add water to adjust to 16°Be′.

[0109] (2) Low pH liquefaction: Use 4% dilute acid to adjust the pH of the slurry to 4.7, add Novozymes low pH liquefaction enzyme at a ratio of 0.07L / ton starch, and then spray at a spray temperature of 114°C, a steam pressure of 3.8 bar, and a serpentine pressure difference of 0.8 bar. After the flash evaporation is completed, Novozymes low pH liquefaction enzyme is added at a rate of 0.19L / ton starch. Enter the laminar flow column and maintain for 2.2 hours. The liquefied material has a DE value of 21.

[0110] (3) Saccharification: Cool the liquefied liquid to 61°C and add 114 mL / min of composite saccharifying enzyme. 3 After saccharification for 34 hours, the glucose content increased to 95.6%.

[0111] (4) Multi-stage protein removal: The saccharification liquid enters the first-stage chamber constant pressure separator for circulation separation to remove the sugar residue in the sugar liquid. The chamber constant pressure separator has a constant pressure of 3.0 bar and a circulation flow rate of 26 m / s. 3 / h, and the circulation time is 0.5bar. Then the sugar solution enters the secondary box-type constant pressure separator to remove impurities such as protein in the sugar solution. The constant pressure of the box-type constant pressure separator is set at 3.0bar, and the circulation flow rate is set at 15m 3 / h, the cycle time is 1.0h. After two-stage separation, the protein content in the sugar solution is reduced to 1.4%, and the light transmittance of the sugar solution discharged from the separator is 97.9%. The sugar solution then enters the protein removal macroporous resin to further remove the residual protein in the sugar solution. After the protein is removed by the macroporous resin, the protein content in the sugar solution is reduced to 0.06%, the light transmittance is 98.5%, and the conductivity is 29μs / cm.

[0112] After the protein removal macroporous resin is saturated with adsorption for a long time, 0.8m 3 4% diluted alkali solution for cleaning, and then use 0.8m 3 Regeneration treatment with 4% dilute hydrochloric acid.

[0113] (5) Low conductivity preparation: The sugar solution is cooled to 32°C using low temperature water and then enters the electrodialysis deionization system for refining. The conductivity of the sugar solution is 15 μs / cm and the transmittance is 98.5%.

[0114] (6) High glucose concentration: The sugar solution was heated to 53°C and then entered the reverse osmosis membrane for concentration. The reverse osmosis membrane concentration pressure was controlled to 8MPa and the reverse osmosis operating temperature was 52°C. The discharge concentration of the sugar solution was controlled at 53%, the pH was controlled to 5.2, and the discharge temperature was lowered to 35°C. Without adding first-grade soybean oil, the concentrated high glucose syrup was directly boiled and tested. The temperature resistance of the syrup was 113°C.

[0115] Effect comparison ratio

[0116] The liquefied liquid in step (2) of the comparative example 1 and the liquefied liquid in step (2) of the embodiment 1 were taken, and the effects of the liquefied liquid were observed, and the results were shown in the following Table 1.

[0117] Table 1 Comparison of liquefaction between Example 1 and Comparative Example 1

[0118]

[0119] Comparing the liquefaction conditions of Example 1 with those of Comparative Example 1, the use of low-pH liquefaction enzyme for liquefaction reduced the amount of chemicals added by 48%, the stratification of the liquefied liquid was more obvious, and the liquefaction effect was better, indicating that the liquefaction effect of the low-pH liquefaction process was better.

[0120] The sugar solution in step (5) of the comparative example 1 was compared with the sugar solution in step (5) of the embodiment 1, and the following results were obtained in Table 2:

[0121] Table 2 Comparison of deionized sugar solution of Example 1 and Comparative Example 1

[0122]

[0123] From the above comparison, it can be seen that the glucose content of Example 1 is 0.3% higher than that of Comparative Example 1, indicating that the low pH liquefaction process can produce more glucose and a higher starch yield. The conductivity of Example 1 is 27% lower and the light transmittance is 0.7% higher than that of Comparative Example 1, indicating that the ion content in Example 1 is lower than that in Comparative Example 1. When the electrodialysis deionization system is used for refining, the low pH liquefaction process is used, the deionization system load is lower, and the refining efficiency is higher.

[0124] 200 mL of the sugar solution in step (7) of comparative example 2 and the sugar solution in step (6) of comparative example 3 were taken for comparison with the sugar solution in step (7) of example 2 and example 3, and the conductivity and light transmittance of the sugar solution were tested. The sugar solution was boiled, its temperature resistance was tested, and the foaming height of the sugar solution was observed, and the results were shown in Table 3 below:

[0125] Table 3 Comparison of Comparative Example 2 / 3 and Example 2 / 3 Syrup

[0126]

[0127] From the above comparison, it can be seen that compared with Comparative Example 2, the foam rise height of Example 2 and Example 3 is reduced by more than 60%, the light transmittance is increased by more than 1%, and the temperature resistance of the syrup is increased by about 10°C or more, indicating that the low conductivity preparation process is used, and the Na in the syrup + and Ca 2+ The content is reduced, and it is not easy to cause changes in the protein structure, which can effectively reduce the foaming of the syrup. The foam rising height of Example 2 and Example 3 is more than 74% lower than that of Comparative Example 3, and the temperature resistance is improved by about 15°C or more, indicating that the addition of edible soybean oil can be used as a defoaming agent to reduce the surface tension of the oil-water interface, thereby achieving the purpose of preparing syrup with low foam, and at the same time, it can also improve the temperature resistance of the syrup.

Claims

1. A method for purifying and producing glucose syrup, characterized in that: 1) Low pH liquefaction: adjusting the pH of the starch slurry to 4.0-5.5, adding a low pH liquefaction enzyme to liquefy, and obtaining a liquefied liquid; 2) Saccharification: adding saccharifying enzyme to the liquefied liquid obtained in step 1) to perform saccharification to obtain saccharified liquid; 3) Removing protein: separating, filtering and chromatography the saccharified liquid obtained in step 2) to reduce the protein content to ≤0.1% to obtain a low-protein sugar liquid; 4) Removing ions: Using an electrodialysis deionization system to remove ions from the low-protein sugar solution obtained in step 3) to obtain a low-conductivity sugar solution; 5) Concentration: Concentrating the low-conductivity sugar solution obtained in step 4) to a concentration of 40-65% to obtain a concentrated syrup; 6) Low foam treatment: Add edible oil to the concentrated syrup obtained in step 5) to obtain.

2. The preparation method according to claim 1, characterized in that: In step 1), the starch slurry is selected from corn starch slurry; Preferably, the pH of the starch slurry is adjusted to 4.5 to 4.8; Preferably, the concentration of the starch slurry is 10°Be′ to 25°Be′.

3. The preparation method according to claim 1, characterized in that: In step 1), the DE value of the liquefied liquid is 10 to 30; Preferably, the dosage of the low pH liquefaction enzyme is 42-64 U / g dry starch; Preferably, the liquefaction temperature is 100-140°C; Preferably, the liquefaction time is 1 to 3 hours.

4. The preparation method according to claim 1, characterized in that: In step 2), the dosage of the saccharifying enzyme is 30-53 U / g dry starch of glucoamylase and 0.64-1.15 U / g dry starch of pullulanase; Preferably, the saccharification temperature is 50°C to 70°C; Preferably, the saccharification time is greater than 20 hours; Preferably, the glucose content of the saccharified liquid is ≥90%.

5. The preparation method according to claim 1, characterized in that: In step 3), the separation and filtration methods include primary separation and secondary separation; Preferably, the primary separation adopts a chamber-type constant pressure separator for cyclic separation treatment; Preferably, the secondary separation adopts a chamber-type constant pressure separator for cyclic separation treatment; Preferably, the chromatography is performed using a deproteinized resin.

6. The preparation method according to claim 5, characterized in that: After the deproteinization resin is treated, the deproteinization resin is cleaned with an alkali solution and regenerated with an acid solution; Preferably, the regenerated acid solution is recovered, and the recovered acid solution is used for adjusting the pH of the starch slurry in step 1).

7. The preparation method according to claim 1, characterized in that: In step 4), the conductivity of the low-conductivity sugar solution is less than 20 μS / cm; and / or The light transmittance of the low-conductivity sugar solution is greater than 98%.

8. The preparation method according to claim 1, characterized in that: In step 5), the concentration is carried out by high temperature reverse osmosis; Preferably, the temperature of the high temperature reverse osmosis is 45-65°C; Preferably, the concentration of the concentrated syrup is 45-60wt%.

9. The preparation method according to claim 1, characterized in that: In step 6), the edible oil includes at least one of soybean oil, peanut oil, corn oil and rapeseed oil; Preferably, the edible oil is added in an amount of 20 to 50 mL per ton of syrup.

10. Application of the preparation method according to claims 1 to 9 in the fields of food, fermentation and spices and flavors.

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