Efficient and environment-friendly starch sugar production method

Abstract

The invention discloses a high-efficiency environment-friendly starch sugar production method, which comprises: (1) crushing sorghum starch, screening, adding into water, adjusting the pH value, adding alpha-amylase and ferulic acid, completely liquefying, adding saccharifying enzyme and potassium sorbate, and saccharifying; and (2) refining and concentrating the saccharified sorghum starch in the step (1), then drying high-concentration sorghum starch syrup to obtain sorghum starch sugar powder, and finally packaging to obtain a finished product.

Description

Technical Field

[0001] This invention belongs to the field of starch sugar processing, and specifically relates to a highly efficient and environmentally friendly method for producing starch sugar. Background Technology

[0002] Starch sugars are sugars produced from starch-containing grains, tubers, and other raw materials through acid processes, acid-enzyme processes, or enzymatic processes. Starch sugars are widely used in beverages, candies, pastries, beer, and other food products. Due to their lower price compared to sucrose and simpler application methods, they are favored by many end-product food companies. However, traditional starch sugar production processes have many shortcomings, such as low sugar yield, severe environmental pollution, and high water consumption. Summary of the Invention

[0003] The present invention aims to improve the yield of starch sugar while reducing environmental pollution, and to maximize the utilization of resources by optimizing the production process.

[0004] This invention uses sorghum starch as raw material and prepares a high-efficiency and environmentally friendly sorghum starch sugar through enzymatic hydrolysis. It has the advantages of simple process, convenient operation and low cost. In addition, the sorghum starch sugar prepared by this invention has high purity, good taste and moderate sweetness, and is suitable for food, beverage, medicine and other fields.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing highly efficient and environmentally friendly sorghum starch sugar includes the following steps: 1. Preparation of purified water: The steam condensate generated during the pre-concentration and concentration processes of starch sugar is recovered and purified sequentially through strong acid resin, weak base resin, and macroporous adsorption resin to obtain purified water with a conductivity <3μS / cm and a 2-aminoacetophenone (2-AP) content ≤0.2μg / L. This water can be used for slurry preparation to reduce impurities in the sugar solution and improve the quality of starch sugar.

[0006] 2. Preparation: Mix edible sorghum starch with purified water at 60-65℃ to form a starch milk with a pH of 20-24°Bé. Adjust the pH to 5.5-6.0, add heat-resistant α-amylase and food-grade soluble calcium salt, and maintain the material temperature at 60-63℃ to ensure that the starch granules swell more fully and improve the dry yield of starch sugar.

[0007] 3. Liquefaction: The prepared slurry is continuously sprayed at 105-110℃, followed by flash evaporation to reduce pressure and temperature. High-temperature resistant α-amylase is then added, and the mixture is kept at 95-100℃ for 90-120 minutes. The liquefied liquid enters a holding tank, where the pH is adjusted in two stages and allowed to settle naturally. Ferulic acid is added, and the resulting clear liquid is cooled to 65-70℃ before entering the saccharification tank. The sugar residue is blocked at the bottom of the holding tank by a perforated plate.

[0008] 4. Recovery of sugar: The sugar residue retained in the holding tank is added to purified water at 65-70°C and transferred to a sugar residue tank. After adjusting the temperature to 65-70°C, saccharifying enzyme preparation is added for saccharification. The saccharified sugar residue liquid is centrifuged to obtain sweet water and sugar residue. Cellulose is added to the sugar residue, and separation is performed by a diaphragm press filter to obtain sugar residue and sweet water, which is used in the subsequent saccharification step.

[0009] 5. Saccharification: The liquefied clear liquid is adjusted to a pH of 4.2-4.6, and saccharifying enzyme preparation is added for primary high-temperature high-concentration saccharification. Then, the sweet water obtained in the recovery of sugar step is added, and saccharifying enzyme preparation is added again for secondary low-temperature low-concentration saccharification. During the saccharification reaction, the temperature, enzyme hydrolysis time, and enzyme dosage need to be controlled to obtain high conversion rate and high-quality sorghum starch sugar liquid. 6. Solid waste-free filtration: The saccharification liquid is heated to 75-85°C and enters the ceramic membrane microfiltration system to obtain clear liquid and residue-containing concentrated liquid. The liquid obtained by pressing and filtering the residue-containing concentrated liquid is returned to the ceramic membrane microfiltration system to achieve solid waste-free discharge.

[0010] 7. Pre-concentration, ion exchange refinement, and concentration: The clear liquid is pre-concentrated to 45%-55%wt by a mechanical steam recompression evaporator, the pre-concentrated liquid is decolorized and refined by an ion exchange system, and finally concentrated to obtain a starch sugar product.

[0011] Advantages (1) The present application uses an enzymatic process to prepare sorghum starch sugar, which has the advantages of simple process, easy operation, and low cost.

[0012] (2) The sorghum starch sugar prepared by the present application has high purity, good taste, and moderate sweetness, and is suitable for food, beverage, medicine, and other fields.

[0013] (3) The present application does not discharge chemical pollutants during the preparation process, meets environmental protection requirements, and is a green and sustainable starch sugar preparation method. DETAILED DESCRIPTION

[0014] The present application will be further described below with reference to specific examples. The raw materials are commercially available, and the saccharifying enzyme is a mixture of glucoamylase and glucan branching enzyme. The addition amount of glucoamylase is 100 U / g, the addition amount of glucan branching enzyme is 100 U / g, and the mixed enzyme preparation is added once at a ratio of 1:1. The addition amount of heat-resistant alpha-amylase is 20 U / g.

[0015] Example 1 A highly efficient and environmentally friendly method for preparing sorghum starch sugar includes the following steps: (1) Raw material pretreatment: The sorghum starch is crushed and sieved to obtain uniform sorghum starch powder.

[0016] (2) Preparation of purified water: the steam condensate water generated in the starch sugar pre-concentration and concentration process is purified by strong acid resin, weak base resin and macroporous adsorption resin in turn to obtain purified water with conductivity <3 μS / cm and 2-aminoacetophenone (2-AP) content ≤0.2 μg / L. The purified water is used for sizing to reduce impurities in the sugar solution and improve the quality of starch sugar.

[0017] (3) Sizing: 2 L of purified water at 60°C is used to mix with 500 g of pretreated sorghum starch to prepare a starch milk with 20-24 °Bé, and the pH is adjusted to 6.0. 8 U / g of high-temperature-resistant α-amylase and 0.5 g of food-grade soluble calcium salt are added to maintain the material temperature at 60°C, so that the starch particles are more fully swollen, and the dry matter yield of starch sugar is improved.

[0018] (4) Liquefaction: the sized material is subjected to continuous jet treatment at 105°C, and after flash decompression and temperature reduction, 2 U / g of high-temperature-resistant α-amylase is added and incubated at 100°C for 100 min. The liquefied liquid is introduced into a holding tank, the pH is adjusted in two stages, and the natural layering is allowed to stand. 0.5 g of ferulic acid is added, and the obtained clear liquid is cooled to 65°C and introduced into a saccharification tank. The sugar dregs are blocked at the bottom of the holding tank by a perforated plate.

[0019] (5) Recovery of sugar: the sugar dregs blocked in the holding tank are added to 65°C purified water and transferred to a sugar dregs tank. After adjusting the temperature to 65°C, 180 U / g of saccharifying enzyme preparation is added for saccharification. The sugar dregs liquid is centrifuged to obtain sweet water and sugar dregs. Cellulose is added to the sugar dregs, and separation is carried out by a diaphragm press filter to obtain sugar dregs and sweet water, which is used in the subsequent saccharification step.

[0020] (6) Saccharification: the clear liquid obtained by liquefaction is adjusted to pH 4.2, and 10 U / g of saccharifying enzyme preparation is added for primary high-temperature high-concentration saccharification. Then, the sweet water obtained in the sugar recovery step is added, and 10 U / g of saccharifying enzyme preparation is added again for secondary low-temperature low-concentration saccharification. The saccharification time is 2 hours.

[0021] (7) Solid waste-free filtration: the saccharification liquid is heated to 75°C and introduced into a ceramic membrane microfiltration system to obtain clear liquid and residue-containing concentrated liquid. The liquid obtained by pressing and filtering the residue-containing concentrated liquid is returned to the ceramic membrane microfiltration system to realize solid waste-free discharge.

[0022] (8) Pre-concentration, ion exchange purification, and concentration: the clear liquid is pre-concentrated to 45%-80% wt by a mechanical vapor recompression evaporator, and the pre-concentrated liquid is decolorized and refined by an ion exchange system, and finally concentrated to obtain a starch sugar product.

[0023] (9) Drying and packaging: the high-concentration sorghum starch syrup is subjected to spray drying at a drying temperature of 70°C for 3 hours to obtain a finished product of sorghum starch.

[0024] Comparative Example 1 The difference from Example 1 is that no alpha-amylase is added in the liquefaction process, and other steps are the same. It is found that no alpha-amylase is added, which will lead to insufficient liquefaction, affecting the subsequent saccharification effect and product quality.

[0025] Comparative Example 2 The difference from Example 1 is that no saccharifying enzyme is added in the saccharification reaction process, and other steps are the same. It is found that no saccharifying enzyme is added, which will lead to incomplete saccharification, low sweetness and poor taste of the product.

[0026] Comparative Example 3 The difference from Example 1 is that no ferulic acid is added in the liquefaction process, and other steps are the same.

[0027] Comparative Example 4 The difference from Example 1 is that no potassium sorbate is added in the saccharification process, and other steps are the same.

[0028] Comparative Example 5 The difference from Example 1 is that the saccharification process is a one-time saccharification process, and other steps are the same.

[0029] Experimental results: (1) DE value measured by Fehling titration: .

[0030] (2) Transmittance: 50g of sample is weighed, dissolved in 50mL of water, injected into 3mL of cuvette, and the absorbance is measured at 440nm wavelength with distilled water as control by spectrophotometer.

[0031] (3) Crystallinity: X-ray diffraction is used to measure the crystallinity.

[0032] The results of Example 1 and Comparative Examples 1-4 are shown in Table 1.

[0033] Table 1 In the present application, by adding amylase, saccharifying enzyme, ferulic acid and potassium sorbate, and step-by-step treatment in the saccharification stage, the DE value, transmittance and crystallinity of starch sugar can be significantly improved.

[0034] The above has described the present application by way of example, but the present application is not limited to the above specific embodiments, and any modification or variation made based on the present application falls within the scope of the present application.

Claims

1. A method for preparing high-efficiency and environment-friendly sorghum starch sugar, characterized in that, The method comprises the following steps: (1) raw material pretreatment: crushing and sieving sorghum starch to obtain sorghum starch powder with uniform particle size; (2) starch liquefaction: adding the pretreated sorghum starch powder into water, adjusting the pH value to a suitable range, adding alpha-amylase for liquefaction treatment, and adding ferulic acid to obtain a liquefied starch solution; (3) starch saccharification: saccharifying the liquefied starch solution, adding saccharifying enzyme and potassium sorbate for saccharification reaction, and saccharifying in steps to obtain a sorghum starch sugar solution; (4) refining and concentration: refining the sorghum starch sugar solution to remove impurities and pigments to obtain a pure sorghum starch sugar solution; and then, concentrating the pure sorghum starch sugar solution to obtain a high-concentration sorghum starch syrup.

2. The method according to claim 1, wherein, In step (2), the pH value is 5.5-6.0, the addition amount of alpha-amylase is 10 U / g, the addition amount of ferulic acid is 0.001-0.005% of the mass of the starch, the liquefaction temperature is 85-95°C, and the time is 30-60 minutes.

3. The method according to claim 1, wherein the method is characterized by, In step (3), the addition amount of saccharifying enzyme is 200 U / g, the addition amount of potassium sorbate is 0.001-0.005% of the mass of the starch, the saccharification reaction temperature is 60-70°C, and the time is 1-3 hours.

4. The method according to claim 1, wherein the method is characterized by, In step (4), the refining treatment comprises filtration, activated carbon decolorization, and ion exchange resin treatment.

5. The method according to claim 1, wherein the method is characterized by, The method further comprises spray drying treatment of the syrup, the drying treatment adopts spray drying or vacuum drying, the drying temperature is 60-80°C, and the time is 2-4 hours.

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