Maltodextrin manufacturing method

Abstract

This invention discloses a method for producing maltodextrin, which belongs to the technical field of developing special-purpose carbohydrate compounding materials. Using starch as raw material, the invention uses dry heat amorphization to decluster starch molecular chains, increase the solid content of the reaction system, and reduce the system viscosity. Then, polyethylene glycol precipitation fractionation, alcohol synthesis fractionation, and membrane fractionation are combined to narrow the molecular weight distribution range of maltodextrin. Finally, mass drying is performed to obtain maltodextrin products with a uniform degree of polymerization distribution, with a maltodextrin yield of over 80%. The various maltodextrins collected in this invention have stable functions and properties, making them highly applicable in the fields of special-purpose functional compounding materials, flavor encapsulation carriers, and food additives. The technical solution of the invention also improves maltodextrin production efficiency, reduces drying costs and energy consumption, and has significant environmental advantages.

Description

[Technical Field]

[0001] The present invention belongs to the technical field of developing special-purpose carbohydrate blending materials, and relates to a method for producing maltodextrin. [Background technology]

[0002] Maltodextrin is a starch hydrolysis product obtained by treating starch with an acid or enzymatic method, with a degree of hydrolysis (DE) of less than 20. Its main components are dextrin with a degree of polymerization (DP) of 10 or more and a small amount of oligosaccharides with a degree of polymerization of 10 or less. It has the characteristics of a wide molecular weight distribution and a large dispersity coefficient.

[0003] Currently, maltodextrin is generally produced by jet liquefaction and hydrothermal gelatinization processes. Jet liquefaction can simultaneously achieve starch gelatinization and enzymatic hydrolysis, but some starch particles are incompletely gelatinized and insufficiently enzymatically hydrolyzed during this process, resulting in low starch utilization. Hydrothermal gelatinization liquefies starch liquefaction by first fully gelatinizing the starch and then enzymatically hydrolyzing it. The limitations of this method include the relatively low solids content of existing starch milk systems (5%-10%, w / w), i.e., the low starch concentration, low production capacity, and high energy consumption for product concentration. Increasing the starch concentration significantly increases the system viscosity, preventing the effective diffusion and liquefaction of saccharification enzymes. This not only affects the enzymatic hydrolysis reaction rate and product yield, but also significantly increases the difficulty of subsequent dextrin separation.

[0004] Maltodextrin products with similar DE values ​​exhibit relatively large differences in molecular weight distribution due to differences in production processes and raw material sources, resulting in completely different properties. Therefore, the DE value is insufficient to reflect the true processing quality of the product, and further differentiation of maltodextrin products at the molecular level is necessary (Chronakis I S. On the molecular characteristics, compositional properties, and structural-functional mechanisms of maltodextrins: A review. DOI: 10.1080 / 10408699891274327). High molecular weight maltodextrin products (DP > 50 ± 5) have physiological functions such as regulating the intestines and delaying the rise in blood glucose levels after meals, making them suitable for use as functional ingredients for special applications. Low molecular weight maltodextrins (DP 30 ± 5 to 50 ± 5) have low hygroscopicity and an appropriate chain length distribution, making them ideal for encapsulating flavorings and active ingredients. Low molecular weight maltodextrins (DP 10 ± 5 to 30 ± 5) have good transparency and solubility, making them stable as food additives. However, low molecular weight maltodextrins contain a high content of reducing sugars such as glucose and maltose, which can absorb moisture and cause browning reactions, which can affect product quality. Therefore, it is important to obtain maltodextrin components with a uniform degree of polymerization through fractionation.

[0005] Currently, methods for separating and purifying maltodextrin mainly include chromatographic separation, membrane filtration separation, and phase transition separation, etc. Chromatographic separation mainly relies on the properties of the filler, and has relatively high costs and small throughput, while phase transition separation achieves precipitation fractionation of substances based on the dependence of the solubility of different molecular fractions in the same polymer on the properties of the solvent, and this single fractionation method has problems such as low fractionation efficiency and relatively large solvent consumption. For example, in Chinese Patent CN113699198A, starch slurry with a mass concentration of 10% to 20% is enzymatically hydrolyzed and liquefied, and activated carbon is added to adsorb the starch, followed by filtration, concentration, and drying to obtain maltodextrin with a DE value of 1 to 2. In Chinese Patent CN104789616B, ethanol, polyethylene glycol, and salt ions are used in combination to separate single-component dextrin, and dextrin components with different molecular weights are obtained by gradually increasing the ethanol concentration during separation. In Chinese Patent CN111304270A, cyclodextrin glucosyltransferase (CGTase), cyclodextrin degrading enzyme (CDase), and / or maltooligosyltrehalose synthase (MTSase) are added to produce non-reducing maltodextrin with a uniform degree of polymerization. As can be seen from the above, the existing methods for producing maltodextrin all have problems such as a low content of starch solids and inefficient separation of maltodextrin with a uniform degree of polymerization.

[0006] In addition, in Chinese patent CN104198668B, polyethylene glycol was used to gradually precipitate dextrin components ranging from large to small molecular weights, and the molecular weight range was 5.443 × 10 3 ~3.297×10 4This method obtains dextrin with a DP of 40. The components obtained by separating the dextrin are homogenized using this method, but the separation process is complicated and time-consuming. Each time polyethylene glycol is added, it must be left to stand for 24 hours. The amount of polyethylene glycol used is large, and the concentration of the dextrin used for separation is only 3.6%, making it unsuitable for separating dextrin with a high solid content. Furthermore, this method has low production capacity and is unsuitable for industrial production. Chinese Patent CN107574198B discloses a method for separating spiral dextrin using alcohol, specifically, a method for separating cyclodextrin using 10% starch milk as raw material with different volume fractions of ethanol solutions. The ethanol separation requires standing at 4°C for 12 hours, and the resulting DP value is at least 40. The dextrin separated by this method has a relatively low concentration, making it unsuitable for separating dextrin with a high solid content. The separation effect is average, and the degree of polymerization of the dextrin is relatively high.

[0007] Therefore, it is urgently necessary to develop a method for producing maltodextrin that has a high starch solid content, high production intensity, high raw material utilization rate and a certain degree of uniformity, making it more suitable for industrial production. Summary of the Invention [Problem to be solved by the invention]

[0008] Maltodextrin produced by conventional hydrothermal gelatinization and jet liquefaction has problems such as a low starch solids content, high viscosity, insufficient enzymatic hydrolysis, high consumption of solvent for separation, and relatively low production capacity. In response to these problems, the present invention provides a method for producing maltodextrin, specifically, by using high-temperature dry heat amorphization, enzymatic hydrolysis liquefaction, a combination of polyethylene glycol precipitation fractionation and alcohol synthesis fractionation, and membrane fractionation techniques to dry large quantities of starch milk with a high solids content, thereby achieving large-scale, efficient production of maltodextrin products with high yields and uniform distribution of the degree of polymerization. [Means for solving the problem]

[0009] A first object of the present invention is to provide a method for producing a maltodextrin product, the method comprising: A dry heat amorphization step (1) in which starch is dry-heat treated at 180 to 200 ° C for 8 to 10 minutes to obtain dry-heat treated starch; (2) an enzymatic hydrolysis liquefaction step in which the dry-heat-treated starch and water are prepared into a starch milk, with the starch accounting for 35% to 40% of the total mass of the starch milk, and the starch milk is then enzymatically hydrolyzed and inactivated to obtain an enzymatic hydrolyzed liquid; a decolorization and impurity removal step (3) in which the enzymatic decomposition solution obtained in step (2) is decolorized and impurity removed to obtain a decolorized and impurity removed solution; First, the decolorized and impurity-removed solution obtained in step (3) is mixed with polyethylene glycol 6000 and centrifuged to obtain a separated component 1 and a supernatant 1, which is a decolorized and impurity-removed solution containing 30 to 40 g of polyethylene glycol 6000 per 100 mL. Next, the supernatant 1 is mixed with absolute ethanol to obtain a mixture, and the mixture is centrifuged to obtain a fractionated component 2 and a supernatant 2, and the volume fraction of absolute ethanol in the mixture is 50% to 60%; Finally, a fractionation step (4) is performed in which the supernatant 2 is separated using a 1000-2000 Da hollow fiber membrane to obtain fractionated components 3. and a drying step (5) of collecting fractionated components 1, 2 and 3 obtained in step (4) and drying them to obtain a maltodextrin product.

[0010] In one embodiment, in step (1), the starch is one or more of cereal starch, algae starch, potato starch, and optionally, the starch includes common corn starch, wheat starch, chlorella starch, tapioca starch, potato starch, and the like.

[0011] In one embodiment, in step (1), the dry heat amorphization is specifically The starch is laid flat between steel discs to a thickness of 2-3 mm and then dry-heat treated at 180-200°C for 8-10 min. Alternatively, the starch is laid flat between steel discs to a thickness of 2-3 mm and then dry-heat treated at 200°C for 8 min.

[0012] In one embodiment, in step (2), the preparation is carried out under conditions of a pH of 5.0 to 6.0 and incubation at 65 to 70°C for 4 to 6 minutes. Alternatively, in step (2), the preparation is carried out under conditions of a pH of 5.0 and incubation at 70°C for 5 minutes.

[0013] In one embodiment, in step (2), the enzymatic degradation is carried out under conditions of adding 10 to 20 U / g of α-amylase, at a pH of 5.0 to 6.0, at 65 to 70°C for 5 to 10 minutes. Alternatively, in step (2), the enzymatic degradation is carried out under conditions of adding 10 U / g of α-amylase, at a pH of 5.0, at 65°C for 5 minutes.

[0014] In one embodiment, in step (3), decolorization and impurity removal are performed using activated carbon and an ion exchange resin. The activated carbon decolorization is performed by incubating at 80 to 90°C for 15 to 30 minutes, and the amount of activated carbon added is 1 g / 100 mL of the enzymatic hydrolysis solution (abbreviated as 1%, w / v).

[0015] In one embodiment, in step (4), the centrifugation is carried out under conditions of 8000 to 9000 r / min for 8 to 10 minutes.

[0016] In one embodiment, in step (4), the molecular weight cutoff of the hollow fiber membrane is 1000 or 2000 Da.

[0017] In one embodiment, in step (5), the drying includes, but is not limited to, heat pump drying, vacuum drying, microwave drying, freeze drying, and hot air drying. Optionally, the drying is hot air drying, and the drying temperature is 50-70°C.

[0018] A second object of the present invention is to provide a maltodextrin product produced by the above method.

[0019] In one embodiment, the degree of polymerization of the maltodextrin product comprises a DP > 50±5, or a DP between 30±5 and 50±5, or a DP between 10±5 and 30±5.

[0020] The third object of the present invention is to provide an application of the above maltodextrin products in the manufacture of special-purpose functional compounding ingredients, flavor substances or active molecule encapsulation carriers, and food additives.

[0021] In one embodiment, the application is to use maltodextrin products with DP > 50 ± 5 as functional formulation ingredients for special purposes.

[0022] In one embodiment, the application is to use a maltodextrin product with a DP between 30±5 and 50±5 as a carrier for encapsulating flavoring substances or active molecules.

[0023] In one embodiment, the application is to use a maltodextrin product with a DP between 10±5 and 30±5 as a food additive. [Effects of the Invention]

[0024] Unlike conventional maltodextrin production methods, this method processes starch using dry heat amorphous technology, enzymatically hydrolyzing starch milk with a high solids content (35%-40%, w / w). After enzymatic hydrolysis, the starch is decolorized with activated carbon, separated using polyethylene glycol precipitation fractionation combined with alcohol synthesis fractionation and membrane fractionation technology, and then dried in large quantities to obtain maltodextrin products with different DP ranges. This method achieves the processing of starch milk with a high solids content, ensuring large-scale, efficient production of maltodextrin products with high yields and uniform degrees of polymerization (DOP), with a maltodextrin yield of over 81%. This method obtains maltodextrin components with three DP ranges, each suitable for different applications.

[0025] specifically, First, the present invention treats starch by dry heat decrystallization, which reduces the viscosity of starch when it is gelatinized, promotes starch declustering and gelatinization, and increases the solid content of starch milk, which can reach 35%-40% (w / w). The method of the present invention improves the production capacity of maltodextrin and is suitable for mass production. (2) The present invention sequentially adopts polyethylene glycol precipitation fractionation, ethanol synthesis fractionation and membrane fractionation technologies to achieve the separation of maltodextrin under the condition of high solid content starch milk, narrowing the distribution range of maltodextrin polymerization degree and obtaining maltodextrin products with a uniform polymerization degree. The present invention improves the starch utilization rate, reaching a maximum of 82.6%. Third, the present invention can directly dry a large amount of the fractions after fractionation, which saves the energy consumption required for the concentration process and the drying cost, has significant environmental advantages, and is more suitable for industrial production. (4) The maltodextrin products prepared in the present invention have degrees of polymerization of component 1 (DP>50±5), component 2 (DP 30±5~50±5), and component 3 (DP 10±5~30±5), respectively. Component 1 can be used as a special-purpose functional compounding ingredient, component 2 can be used as an encapsulation carrier for flavor substances and active molecules, and component 3 can be used as a food additive, and in this respect, they have extremely high future application potential. DETAILED DESCRIPTION OF THE INVENTION

[0026] Preferred embodiments of the present invention will be described below. It should be understood that the examples are provided for better understanding of the present invention and are not intended to limit the present invention.

[0027] Materials and Equipment The high-temperature dry heat amorphization apparatus used in the following experiments is a GZX-9146MBE type ventilated drying box manufactured by Shanghai Boxun Co., Ltd., and the α-amylase purchased from Sigma Co., Ltd. has an enzyme activity of 50,000 U / mL.

[0028] Testing Methodology 1. Measurement of starch hydrolysis rate (DE) The reducing sugar content is measured according to the Lane-Eynon method, and the result is used to calculate the DE content. Take 0.50g (anhydrous basis) each of anhydrous glucose standard solution and maltodextrin product, add an appropriate amount of distilled water, dissolve, and make the volume to 250mL. Shake and mix to make glucose standard solution and sample solution. Measure out 25mL of Fehling's reagent and 10mL of distilled water, shake, and heat until boiling, then add 2 drops of 1% methylene blue solution. Titrate with glucose standard solution or sample solution until the blue color just disappears, and record the volume of glucose standard solution or sample solution required. The DE value is the percentage of reducing sugars (in glucose) that occupy the dry matter of the syrup, and the calculation formula is: JPEG2026502716000001.jpg9170.

[0029] 2. Measurement of starch utilization rate The starch utilization, or maltodextrin yield, is expressed as the ratio between the total mass of maltodextrin obtained after drying and the mass of starch used.

[0030] 3. Measurement of chain length distribution of maltodextrin The chain length distribution of maltodextrins was measured by HPAEC-PAD using a pulsed amperometric detector (ICS-5000+), a chromatographic column (Dionex CarboPAC PA200), a mobile phase (NaOH solution, 150 mmol / L), a flow rate (0.4 mL / min), and an injection volume (25 μL).

[0031] Example 1 Maltodextrin production and separation First, corn starch is dry-heat decrystallized at 200°C to prepare a 35% (w / w) starch milk, which is then enzymatically hydrolyzed at 70°C. After enzymatic hydrolysis, the starch is decolorized with activated carbon, and then separated by 40% (w / v) polyethylene glycol 6000 precipitation, 60% (v / v) ethanol synthesis, and membrane fractionation. The resulting product is then dried to obtain maltodextrin products with different degrees of polymerization.

[0032] The specific experimental steps are: A dry heat amorphization step (1) in which corn starch is spread evenly on a steel disc to a thickness of 3 mm and dry heat treated at 200 ° C for 8 minutes to obtain dry heat treated starch; an enzymatic hydrolysis liquefaction step (2) in which water is added to the dry-heat-treated starch to adjust the pH to 5.0, and the mixture is kept at 70°C for 5 minutes to prepare a 35% (w / w, anhydrous starch accounts for the total mass of the starch milk) starch milk; thereafter, 10 U / g of α-amylase is added to the starch milk to enzymatically hydrolyze the starch milk at pH 5.0 and 70°C for 5 minutes; and the pH of the solution is adjusted to 4.5 to inactivate the enzyme, thereby obtaining an enzymatic hydrolysis solution; a decolorization and impurity removal step (3) in which 1% (w / v, g / mL) activated carbon is added to the enzymatic hydrolysis solution, and the solution is decolorized at 80°C for 30 minutes, and then metal salts and pigments are removed using an ion exchange resin to obtain a decolorized and impurity-removed solution; The decolorized and impurity-removed solution is subjected to polyethylene glycol precipitation fractionation, ethanol synthesis fractionation, and membrane fractionation and collection in sequence to obtain maltodextrin components with a uniform degree of polymerization distribution, i.e., In polyethylene glycol precipitation fractionation, the decolorized and impurity-removed solution was mixed with polyethylene glycol 6000, thoroughly stirred uniformly, and then left to stand for 2 hours. Then, the solution was centrifuged at 8000 r / min for 10 minutes to obtain fraction 1 and supernatant 1. The amount of polyethylene glycol 6000 added was 40% (w / v, g / mL). In the ethanol synthesis fractionation, the supernatant 1 is mixed with absolute ethanol to obtain a mixture, and the volume fraction of absolute ethanol in the mixture reaches 60%, and the mixture is left standing for 30 minutes, and then centrifuged at 8000 r / min for 10 minutes to obtain fraction 2 and supernatant 2. a fractionation step (4) in which the supernatant 2 is separated using a 2000 Da hollow fiber membrane to obtain fractionated components 3; and a drying step (5) of drying fractionated components 1, 2 and 3 with hot air at 70°C to obtain three sets of maltodextrin products with uniform degrees of polymerization.

[0033] Example 2 Maltodextrin production and separation First, corn starch is decrystallized by dry heat at 180°C to prepare a 35% (w / w) starch milk, which is then enzymatically hydrolyzed at 65°C. After enzymatic hydrolysis, the starch is decolorized with activated carbon, and then separated by precipitation with 30% (w / v) polyethylene glycol 6000, synthesis with 50% (v / v) ethanol, and membrane fractionation. The resulting product is then dried to obtain maltodextrin products with different degrees of polymerization.

[0034] The specific experimental steps are: A dry heat amorphization step (1) in which corn starch is spread evenly on a steel disc to a thickness of 2 mm and dry heat treated at 180 ° C for 10 minutes to obtain dry heat treated starch; an enzymatic hydrolysis liquefaction step (2) in which water is added to the dry-heat-treated starch to adjust the pH to 6.0, and the mixture is kept at 65°C for 5 minutes to prepare a 35% (w / w, anhydrous starch accounts for the total mass of the starch milk) starch milk; then, 20 U / g of α-amylase is added to the starch milk, and the starch milk is enzymatically hydrolyzed at pH 5.0 and 65°C for 10 minutes, and the pH of the solution is adjusted to 4.5 to inactivate the enzyme, thereby obtaining an enzymatic hydrolysis solution; a decolorization and impurity removal step (3) in which 1% (w / v, g / mL) activated carbon is added to the enzymatic hydrolysis solution, and the solution is decolorized at 90°C for 30 minutes, and then metal salts and pigments are removed using an ion exchange resin to obtain a decolorized and impurity-removed solution; The decolorized and impurity-removed solution is subjected to polyethylene glycol precipitation fractionation, ethanol synthesis fractionation, and membrane fractionation and collection in sequence to obtain maltodextrin components with a uniform degree of polymerization distribution, i.e., In polyethylene glycol precipitation fractionation, the decolorized and impurity-removed solution was mixed with polyethylene glycol 6000, thoroughly stirred uniformly, and then left to stand for 2 hours. Then, the solution was centrifuged at 8000 r / min for 10 minutes to obtain fraction 1 and supernatant 1. The amount of polyethylene glycol 6000 added was 30% (w / v, g / mL). In the ethanol synthesis fractionation, the supernatant 1 is mixed with absolute ethanol to obtain a mixture, and the volume fraction of absolute ethanol in the mixture reaches 50%, and the mixture is left to stand for 30 minutes, and then centrifuged at 8000 r / min for 10 minutes to obtain fraction 2 and supernatant 2. a fractionation step (4) in which the supernatant 2 is separated using a 2000 Da hollow fiber membrane to obtain fractionated components 3; and a drying step (5) of drying fractionated components 1, 2 and 3 with hot air at 70°C to obtain three sets of maltodextrin products with uniform degrees of polymerization.

[0035] Example 3 Maltodextrin production and separation First, tapioca starch is dry-heat decrystallized at 180°C to prepare a 40% (w / w) starch milk, which is then enzymatically hydrolyzed at 70°C. After enzymatic hydrolysis, the starch is decolorized with activated carbon, and then separated by 30% (w / v) polyethylene glycol precipitation, 60% (v / v) ethanol synthesis, and membrane fractionation. The resulting product is then dried to obtain maltodextrin products with different degrees of polymerization.

[0036] The specific experimental steps are: A dry heat amorphization step (1) in which tapioca starch is spread evenly on a steel disc to a thickness of 3 mm and dry-heat treated at 180 ° C for 10 minutes to obtain dry-heat treated starch; an enzymatic hydrolysis liquefaction step (2) in which water is added to the dry-heat-treated starch to adjust the pH to 5.0, and the mixture is kept at 70°C for 5 minutes to prepare a 40% (w / w, anhydrous starch accounts for the total mass of the starch milk) starch milk; then, 20 U / g of α-amylase is added to the starch milk to enzymatically hydrolyze the starch milk at pH 5.0 and 70°C for 10 minutes; and the pH of the solution is adjusted to 4.5 to inactivate the enzyme, thereby obtaining an enzymatic hydrolysis solution; a decolorization and impurity removal step (3) in which 1% (w / v, g / mL) activated carbon is added to the enzymatic hydrolysis solution, and the solution is decolorized at 80°C for 30 minutes, and then metal salts and pigments are removed using an ion exchange resin to obtain a decolorized and impurity-removed solution; The decolorized and impurity-removed solution is subjected to polyethylene glycol precipitation fractionation, ethanol synthesis fractionation, and membrane fractionation and collection in sequence to obtain maltodextrin components with a uniform degree of polymerization distribution, i.e., In polyethylene glycol precipitation fractionation, the decolorized and impurity-removed solution was mixed with polyethylene glycol 6000, thoroughly stirred uniformly, and then left to stand for 2 hours. Then, the solution was centrifuged at 8000 r / min for 10 minutes to obtain fraction 1 and supernatant 1. The amount of polyethylene glycol 6000 added was 30% (w / v, g / mL). In the ethanol synthesis fractionation, the supernatant 1 is mixed with absolute ethanol to obtain a mixture, and the volume fraction of absolute ethanol in the mixture reaches 60%, and the mixture is left standing for 30 minutes, and then centrifuged at 8000 r / min for 10 minutes to obtain fraction 2 and supernatant 2. a fractionation step (4) in which the supernatant 2 is separated using a 1000 Da hollow fiber membrane to obtain fractionated components 3; and a drying step (5) of drying fractionated components 1, 2 and 3 with hot air at 70°C to obtain three sets of maltodextrin products with uniform degrees of polymerization.

[0037] Comparative Example 1 Production of maltodextrin by hydrothermal gelatinization Based on Example 1, step (1) and step (2) were modified to prepare starch milk at 35% (w / w, anhydrous starch accounts for the total mass of the starch milk) and gelatinize it in a boiling water bath for 30 minutes, while other conditions were the same as in Example 1.

[0038] Comparative Example 2 Change of dry heat amorphization temperature to 140℃ Based on Example 1, the dry heat amorphization temperature in step (1) was changed to 140°C, and other conditions were the same as in Example 1.

[0039] Comparative Example 3 Production of maltodextrin by jet liquefaction. Based on Example 1, the dry heat amorphization operation in step (1) was omitted, and step (2) involved gelatinizing the starch by jet liquefaction, i.e., adding 10 U / g of α-amylase to the starch milk and jet liquefying it to obtain a liquefied liquid. The jet pressure of the liquefied material was set to 0.35 MPa, the steam pressure to 0.1 MPa, the temperature to 90°C, the time to 8 minutes, and then the incubation at 70°C for 5 minutes. The other conditions were the same as in Example 1.

[0040] Comparative Example 4 No fractionation in the production of maltodextrin Based on Example 1, the fractionation in step (4) was omitted, and the other conditions were the same as in Example 1. The produced maltodextrin was detected and found to have a DP distribution of 1 to 70, a non-uniform molecular weight distribution, and a mixture of glucose, maltose, oligosaccharides, and polysaccharides.

[0041] Comparative Example 5 Using polyethylene glycol precipitation fractionation alone in the production of maltodextrin. Based on Example 1, the separation step in step (4) is: The decolorized and impurity-removed solution was mixed with polyethylene glycol 6000 to make the amount of polyethylene glycol 6000 added 40% (w / v, g / mL), thoroughly stirred uniformly, left to stand for 2 hours, and then centrifuged at 8000 r / min for 10 minutes to obtain fraction 1 and supernatant 1. Continue adding polyethylene glycol 6000 to the supernatant 1 until the amount of polyethylene glycol 6000 added reaches 50% (w / v, g / mL), thoroughly and uniformly stir, then let stand for 2 hours, and then centrifuged at 8000 r / min for 10 minutes to obtain component 2. The other conditions are the same as in Example 1.

[0042] Comparative Example 6 Only alcohol synthesis fractionation technology is used in the production of maltodextrin. Based on Example 1, the separation step in step (4) is: The decolorized and impurity-removed solution was mixed with absolute ethanol to obtain a mixture, and the volume fraction of absolute ethanol in the mixture reached 30%. The mixture was then left to stand for 30 minutes and centrifuged at 8000 r / min for 10 minutes. The resulting precipitate was maltodextrin fraction 1 and supernatant 1. Absolute ethanol is added to the supernatant 1 until the volume fraction of absolute ethanol reaches 60%, and the mixture is left to stand for 30 minutes. The mixture is then centrifuged at 8000 r / min for 10 minutes. The resulting precipitate is maltodextrin fraction 2 and supernatant 2. Add anhydrous ethanol to the supernatant 2 until the volume fraction of anhydrous ethanol reaches 80%, let stand for 30 minutes, and then centrifuge at 8000 r / min for 10 minutes. The resulting precipitate is maltodextrin fraction 3, and the other conditions are the same as in Example 1.

[0043] Comparative Example 7 Using only membrane fractionation technology in the production of maltodextrin Based on Example 1, the separation step in step (4) is: The decolorized and impurity-removed solutions separated using hollow fiber membranes with molecular weight cutoffs of 10,000, 5,000, and 2,000 Da were sequentially selected and used to obtain maltodextrin fractions 1, 2, and 3, respectively, with other conditions identical to those in Example 1.

[0044] Comparative Example 8 Changing the fractionation separation sequence in maltodextrin production Based on Example 1, the order of the fractionation steps in step (4) is: Ethanol synthesis fractionation is carried out, that is, the decolorized and impurity-removed solution is mixed with absolute ethanol until the volume fraction of absolute ethanol reaches 60%, and the mixture is left to stand for 30 minutes, and then centrifuged at 8000 r / min for 10 minutes. The resulting precipitate is maltodextrin fraction 1 and supernatant 1. Polyethylene glycol precipitation fractionation is carried out, that is, the supernatant 1 is mixed with polyethylene glycol 6000, the amount of polyethylene glycol 6000 added is 40% (w / v, g / mL), and the mixture is thoroughly stirred uniformly, left to stand for 2 hours, and then centrifuged at 8000 r / min for 10 minutes. The resulting precipitate is maltodextrin fraction 2 and supernatant 2. Membrane fractionation was performed, i.e., the membrane fractionation was modified to separate the supernatant obtained from the ethanol synthesis fractionation using a hollow fiber membrane with a molecular weight cutoff of 2000 Da to obtain maltodextrin fraction 3, and other conditions were the same as in Example 1.

[0045] The polymerization degrees and yields of the maltodextrin products produced in Examples 1 to 3 and Comparative Examples 1 to 8 were determined, and the results are shown in Tables 1 and 2.

[0046] JPEG2026502716000002.jpg118170Note: DP represents the degree of polymerization, "-" represents the absence of the fraction, and the content of the final separated product represents the percentage of the maltodextrins in the three fractions based on the total weight of maltodextrin, with the sum of the three components being 100%.

[0047] JPEG2026502716000003.jpg114170

[0048] As can be seen from Tables 1 and 2, the method of Example 1 achieved a maltodextrin yield (starch utilization rate) of 82.1%, with the chain lengths of maltodextrin fractions 1, 2, and 3 ranging from DP>50, DP 30-50, and DP 10-30, respectively. The method of Example 2 achieved a maltodextrin yield of 81.7%, with the chain lengths of maltodextrin fractions 1, 2, and 3 ranging from DP>55, DP 35-55, and DP 10-35, respectively. The method of Example 3 achieved a maltodextrin yield of 82.6%, with the chain lengths of maltodextrin fractions 1, 2, and 3 ranging from DP>55, DP 25-55, and DP 5-25, respectively.

[0049] A comparison of Example 1 and Comparative Example 4 shows that the degree of polymerization of the maltodextrin products after fractionation was uniform, with the maltodextrin products falling into three groups: DP > 50, DP 30-50, and DP 10-30. Comparative Example 4 was unseparated maltodextrin with a DP between 1 and 70. The maltodextrin produced was a mixture of glucose, maltose, oligosaccharides, and polysaccharides, with low uniformity. Glucose and maltose have high reducing properties, and when present together with amino acids or proteins, they are prone to undergo Maillard reaction, which reduces the quality of the maltodextrin product.

[0050] Furthermore, in Example 1, the three sets of maltodextrin components obtained after fractionation had improved polymerization uniformity, and the hot air drying technique could be used to rapidly dry the products, which reduces drying costs compared with the concentration and spray drying techniques required for unfractionated maltodextrin, and is advantageous for improving the stability of maltodextrin in industrial production.

[0051] As can be seen from a comparison between Examples 1 to 3 and Comparative Examples 1 to 3, treating starch with dry heat amorphization can increase the maltodextrin yield to 80% or more. As can be seen from a comparison between Example 1 and Comparative Example 2, the temperature of dry heat amorphization is an important factor affecting the maltodextrin yield, and maltodextrin produced by dry heat treating starch at a relatively low temperature has a relatively low yield.

[0052] As can be seen from the above, the viscosity of starch milk is high under hydrothermal gelatinization conditions, which hinders the diffusion and contact between the enzyme and the substrate during the subsequent enzymatic hydrolysis reaction, slowing down the reaction rate and resulting in insufficient enzymatic hydrolysis, resulting in a low maltodextrin yield. However, lowering the dry heat amorphization temperature reduces the degree of declustering of starch chains, increasing the viscosity of the starch paste and weakening its fluidity, resulting in insufficient enzymatic hydrolysis and further increasing fractionation loss. During the jet liquefaction process, starch gelatinization and enzymatic hydrolysis occur simultaneously, and the starch is not thoroughly gelatinized, resulting in a low maltodextrin yield. Jet liquefaction further increases the energy consumption and economic costs of maltodextrin production.

[0053] As can be seen from a comparison of Example 1 with Comparative Examples 6 and 7, the maltodextrin yield obtained by sequentially performing polyethylene glycol precipitation fractionation, ethanol synthesis fractionation, and membrane fractionation is higher than that obtained by using only one of these separation methods. As can be seen from a comparison of Example 1 with Comparative Examples 5 and 8, only a specific sequence of fractionation steps results in a high separation efficiency for maltodextrin components with different DP values, while maintaining a high yield.

[0054] In Comparative Example 5, only two sets of maltodextrin components with degrees of polymerization (DP) > 50 and 1-50 were obtained. While the maltodextrin yield was relatively high, the separation efficiency was relatively low. Maltodextrin components with DPs of 1-50 are not very effective for encapsulating flavorings or active ingredients, and they lack good transparency and solubility. Furthermore, they contain low-molecular-weight reducing sugars, which make them prone to moisture absorption and browning. The reason for the poor separation efficiency in Comparative Example 5 is that when the amount of polyethylene glycol 6000 added reaches 40% (w / v, g / mL), maltodextrin components with DP > 50 precipitate during fractionation. The DP of the remaining maltodextrin components in the supernatant is < 50. When polyethylene glycol is continuously added, the reaction system becomes too viscous to narrow the distribution range of the polymerization degree of the product by centrifugation.

[0055] The reason why the yield of maltodextrin produced in Comparative Example 6 was 65.5% is that the volume of the maltodextrin solution increased significantly during the addition of anhydrous ethanol, resulting in a decrease in concentration and an increase in separation loss.

[0056] The yield of maltodextrin produced in Comparative Example 7 was reduced to 58.4%. This is because the maltodextrin solution with a high substrate concentration is difficult to fractionate using membrane separation, resulting in a reduced maltodextrin yield. At the same time, the amount of hollow fiber membrane used in the separation process was relatively large, resulting in increased maltodextrin loss and increased costs for the hollow fiber membrane.

[0057] In Comparative Example 8, only two sets of maltodextrin components with chain length distributions of DP > 30 and DP 10-30 were obtained. Although the polymerization degree distribution range of maltodextrin with DP > 30 could not be narrowed by adjusting the order of the fractionation steps, maltodextrin components with DP > 50 and DP 30-50 were not separated. This is because it is difficult to precipitate maltodextrin components with relatively low molecular weights using polyethylene glycol. However, if ethanol synthesis fractionation is performed first, components with relatively low DP values ​​and components with relatively high DP values ​​are precipitated together, resulting in the separated maltodextrin components with DP > 30. In this case, precipitation fractionation of maltodextrin components with DP < 30 in Supernatant 1 using polyethylene glycol does not produce a significant separation effect. Of the components separated in this order, only the maltodextrin components with a DP of 10 to 30 can be used to encapsulate flavor components and active substances. However, components with a DP of >30 cannot be separated from components with a DP of >50 and 30 to 50, making them less effective as functional compounding ingredients for special purposes and resulting in low encapsulation efficiency for flavor components and active substances.

[0058] In summary, polyethylene glycol has a relatively high fractionation effect on high molecular weight maltodextrin and can effectively precipitate maltodextrin components with a DP of >50. Ethanol synthesis technology can effectively separate maltodextrin components with a DP of >30, but cannot separate maltodextrin components with a DP of <15. In order to save solvent consumption and drying costs, membrane separation is used to filter maltodextrin components with a DP of <10. By combining the three, three sets of maltodextrin components with chain length distributions of DP >50±5, DP 30±5~50±5, and DP 10±5~30±5 can be obtained, and each component has a corresponding range of use.

[0059] The above description is merely a preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for producing maltodextrin, comprising the steps of: A dry heat amorphization step (1) of dry-heat treating starch at 180 to 200 ° C. for 8 to 10 minutes to obtain dry-heat treated starch; (2) an enzymatic decomposition and liquefaction step in which the dry-heat-treated starch and water are prepared into a starch milk, with the starch accounting for 35% to 40% of the total mass of the starch milk, and then the starch milk is enzymatically decomposed and inactivated to obtain an enzymatic decomposition liquid; A decolorization / impurity removal step (3) of decolorizing and removing impurities from the enzymatic decomposition solution obtained in step (2) to obtain a decolorized / impurity-removed solution; First, the decolorized and impurity-removed solution obtained in step (3) is mixed with polyethylene glycol 6000 and centrifuged to obtain a separated component 1 and a supernatant 1, which is a decolorized and impurity-removed solution containing 30 to 40 g / 100 mL of polyethylene glycol 6000; Next, the supernatant 1 is mixed with absolute ethanol to obtain a mixture, and the mixture is centrifuged to obtain a fractionated component 2 and a supernatant 2, and the volume fraction of absolute ethanol in the mixture is 50% to 60%; Finally, a fractionation step (4) is performed by separating the supernatant 2 using a 1000-2000 Da hollow fiber membrane to obtain fractionated components 3; and a drying step (5) of collecting fraction 1, fraction 2 and fraction 3 obtained in step (4) and drying them to obtain a maltodextrin product.

2. 2. The method for producing maltodextrin according to claim 1, wherein in step (1), the starch includes, but is not limited to, cereal starch, algae starch, and potato starch.

3. 2. The method for producing maltodextrin according to claim 1, wherein in step (2), the preparation is carried out under conditions of pH 5.0 to 6.0 and incubation at 65 to 70°C for 4 to 6 minutes.

4. 2. The method for producing maltodextrin according to claim 1, wherein in step (2), the enzymatic hydrolysis is carried out under conditions of adding 10 to 20 U / g of α-amylase, a pH of 5.0 to 6.0, and a temperature of 65 to 70°C for 5 to 10 minutes.

5. 2. The method for producing maltodextrin according to claim 1, wherein in step (3), decolorization and impurity removal are carried out using activated carbon and an ion exchange resin, the decolorization with activated carbon is carried out by incubating at 80 to 90°C for 15 to 30 minutes, and the amount of activated carbon added is 1 g / 100 mL of the enzymatic hydrolysis solution.

6. A maltodextrin product obtained by the process according to any one of claims 1 to 5.

7. 7. The maltodextrin product according to claim 6, characterized in that the degree of polymerization of the maltodextrin product is DP>50±5, or DP between 30±5 and 50±5, or DP between 10±5 and 30±5.

8. The application of the maltodextrin product according to claim 6 or claim 7 in the production of functional compounding ingredients for special purposes, flavor substances or active molecule encapsulation carriers, and food additives.

9. The application is to use maltodextrin products with DP>50±5 as functional compounding ingredients for special purposes; Maltodextrin products having a DP between 30±5 and 50±5 are used as flavoring substances or active molecule encapsulation carriers; The application according to claim 8, characterized in that the maltodextrin product with DP between 10±5 and 30±5 is used as a food additive.

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