阅读说明：本技术 一种聚合度均一的聚葡萄糖及其制备方法 (Polydextrose with uniform polymerization degree and preparation method thereof ) 是由 杨腾腾 邵先豹 亓慧娟 刘双双 张兴晶 祝书红 于 2020-11-19 设计创作，主要内容包括：本发明涉及一种聚合度均一的聚葡萄糖及其制备方法。所述聚葡萄糖的平均分子量为2000～8000,包含20～70％重量百分比的聚合度为13-40的聚葡萄糖,20～50％重量百分比的聚合度为8-13的聚葡萄糖,5～30％重量百分比的聚合度为3-8的聚葡萄糖。本发明还公开了上述聚葡萄糖的制备方法,该方法是以葡萄糖浆为原料加入山梨醇和食用酸后分段控温聚合反应,粉碎后加水溶解、脱色过滤,经膜分离和色谱分离后获得高均一度聚葡萄糖。本发明通过分段控温进行聚合反应实现了聚葡萄糖聚合度的可控性,采用膜分离技术结合色谱分离技术,进行精确分离,制备得到平均分子量为2000～8000,聚合度13-40,8-13,3-8等不同规格的,聚合度均一的聚葡萄糖产品,可满足下游不同行业的特殊要求。(The invention relates to polydextrose with uniform polymerization degree and a preparation method thereof. The average molecular weight of the polydextrose is 2000-8000, and the polydextrose comprises 20-70 wt% of polydextrose with the polymerization degree of 13-40, 20-50 wt% of polydextrose with the polymerization degree of 8-13 and 5-30 wt% of polydextrose with the polymerization degree of 3-8. The invention also discloses a preparation method of the polydextrose, which comprises the steps of adding sorbitol and edible acid into glucose syrup as raw materials, carrying out segmented temperature-controlled polymerization reaction, crushing, adding water for dissolving, decoloring and filtering, and carrying out membrane separation and chromatographic separation to obtain the polydextrose with high uniformity. The invention realizes the controllability of the polymerization degree of the polydextrose by carrying out polymerization reaction through segmented temperature control, adopts a membrane separation technology and a chromatographic separation technology to carry out accurate separation, prepares polydextrose products with different specifications, such as the average molecular weight of 2000-8000, the polymerization degree of 13-40, 8-13, 3-8 and the like and uniform polymerization degree, and can meet the special requirements of different downstream industries.)

1. The preparation method of the polydextrose with uniform polymerization degree comprises the following steps:

(1) adding water into the starch raw material to adjust the starch slurry, and then liquefying, saccharifying and concentrating to obtain glucose syrup;

(2) adding sorbitol and edible acid into the glucose syrup obtained in the step (1), and then carrying out segmented temperature-control polymerization reaction, wherein the segmented temperature-control polymerization reaction is to carry out polymerization reaction for 6-24 min at 130-150 ℃, then carry out polymerization reaction for 12-48 min at 140-160 ℃, and finally carry out cooling for 12-48 min at 30-40 ℃ to obtain crude polydextrose with the content of more than or equal to 95%;

(3) and (3) crushing the crude polydextrose obtained in the step (2), adding water to dissolve, decoloring and filtering, and performing membrane separation and chromatographic separation to obtain polydextrose with uniform polymerization degree.

2. The method for preparing polydextrose according to claim 1 wherein in step (1) the concentration of said starch slurry is 16 to 17 baume and the pH is 5 to 6.

3. The method for preparing polydextrose according to claim 1 wherein in step (1) said starch is corn starch, tapioca starch or wheat starch.

4. The method for preparing polydextrose according to claim 1 wherein in step (1) said concentration is such that the glucose syrup solids are greater than or equal to 80%.

5. The method for preparing polydextrose according to claim 1, wherein in the step (2), the sorbitol is added in an amount of 2-10% by mass of the glucose syrup.

6. The method for preparing polydextrose according to claim 1 wherein in step (2) said edible acid is citric acid, phosphoric acid, fumaric acid, acetic acid or lactic acid; the adding amount of the edible acid is 0.5-1.5% of the mass of the glucose syrup.

7. The method for preparing polydextrose according to claim 1, wherein in step (2), the step temperature controlled polymerization is carried out in a vacuum belt dryer, and the operation speed of the vacuum belt dryer is 30-120 min/week.

8. The method for preparing polydextrose according to claim 1, wherein in the step (2), the step-wise temperature-controlled polymerization comprises polymerization at 130-140 ℃ for 10-20 min, polymerization at 150-160 ℃ for 20-40 min, and cooling at 30-40 ℃ for 20-40 min.

9. The method for preparing polydextrose according to claim 1, wherein in the step (3), the membrane separation is performed for 3 times by using a nanofiltration membrane, and the molecular interception amount of the nanofiltration membrane is 1000-3000.

10. The polydextrose with uniform polymerization degree is prepared by the preparation method of claim 1, has an average molecular weight of 2000-8000, and comprises 20-70 wt% of polydextrose with a polymerization degree of 13-40, 20-50 wt% of polydextrose with a polymerization degree of 8-13 and 5-30 wt% of polydextrose with a polymerization degree of 3-8.

Technical Field

The invention belongs to the technical field of water-soluble dietary fiber preparation, and particularly relates to polydextrose with uniform polymerization degree and a preparation method thereof.

Background

Polydextrose is a novel water-soluble dietary fiber, is obtained by taking glucose and sorbitol as raw materials and carrying out polymerization reaction under acidic and vacuum conditions, has been approved by more than fifty countries as a health food ingredient to be used so far, is used for manufacturing a large amount of fiber-reinforced food, and has the function of keeping intestines and stomach unobstructed after being eaten. Polydextrose is combined with bile acid in vivo to be removed, serum cholesterol is obviously reduced, satiety is more easily caused, and postprandial blood sugar level and the like can be obviously reduced.

However, the current commercial polydextrose products have wide polymerization degree distribution range, the average molecular weight is from 342 to 22000, the physiological effect of the products is low, the processing performance is poor, and the increasing demands of consumers cannot be met.

Chinese patent document CN104844725A discloses a method for producing high-purity and high-polymerization-degree polydextrose, which comprises the steps of blending, polymerization, reaction termination, decolorization, membrane separation, ion exchange, concentration, and spray drying.

The polydextrose prepared by the method has the molecular weight of 700-20000, the polymerization degree distribution range is wide, and the problems of low physiological effect and poor processing performance of products exist.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides polydextrose with uniform polymerization degree and a preparation method thereof.

The technical scheme of the invention is as follows:

the preparation method of the polydextrose with uniform polymerization degree comprises the following steps:

(1) adding water into the starch raw material to adjust the starch slurry, and then liquefying, saccharifying and concentrating to obtain glucose syrup;

(2) adding sorbitol and edible acid into the glucose syrup obtained in the step (1), and then carrying out segmented temperature control polymerization reaction, wherein the segmented temperature control polymerization reaction is that polymerization reaction is carried out for 6-24 min at 130-150 ℃, then polymerization reaction is carried out for 12-48 min at 140-160 ℃, and finally cooling is carried out for 12-48 min at 30-50 ℃ to obtain crude polydextrose with the content being more than or equal to 95%;

(3) and (3) crushing the crude polydextrose obtained in the step (2), adding water for dissolving, decoloring and filtering, and performing membrane separation and chromatographic separation to obtain the polydextrose with high uniformity.

According to the invention, in the step (1), the concentration of the starch slurry is 16-17 Baume, and the pH value is 5-6.

According to the invention, in the step (1), the starch is preferably corn starch, tapioca starch or wheat starch.

Preferably, in step (1), the concentration is performed until the solid content of the glucose syrup is more than or equal to 80%.

According to the invention, in the step (2), the addition amount of sorbitol is 2-10% of the mass of the glucose syrup.

Preferably, in step (2), the edible acid is citric acid, phosphoric acid, fumaric acid, acetic acid or lactic acid.

According to the invention, in the step (2), the adding amount of the edible acid is 0.5-1.5% of the mass of the glucose syrup.

Preferably, in the step (2), the step-by-step temperature-controlled polymerization reaction is carried out in a vacuum belt dryer, and the running speed of the vacuum belt dryer is 30-120 min/week.

According to the preferable selection of the invention, in the step (2), the step temperature control polymerization reaction is firstly polymerization reaction at 130-140 ℃ for 10-20 min, then polymerization reaction at 150-160 ℃ for 20-40 min, and finally cooling at 30-40 ℃ for 20-40 min.

According to the invention, in the step (3), preferably, the membrane separation is performed for 3 times by using a nanofiltration membrane, and the molecular interception amount of the nanofiltration membrane is 1000-3000.

The invention also provides polydextrose with uniform polymerization degree, which is obtained by adopting the preparation method, wherein the polydextrose has the average molecular weight of 2000-8000, and comprises 20-70 wt% of polydextrose with the polymerization degree of 13-40, 20-50 wt% of polydextrose with the polymerization degree of 8-13 and 5-30 wt% of polydextrose with the polymerization degree of 3-8.

The liquefaction, saccharification, decolorization filtration and chromatographic separation in the present invention are carried out according to the prior art.

The invention has the technical characteristics that:

the invention adopts the sectional temperature control to prepare the polydextrose, which is different from the traditional intermittent production mode of a reaction kettle, and the principle of the process for controlling the polymerization degree is that materials form a film on production equipment, the materials advance at a constant speed, the reaction conditions of the materials are consistent, partial polymerization mainly based on evaporation is firstly carried out at a lower temperature for a short time by controlling the reaction temperature, the concentration of the materials is improved, then main polymerization mainly based on evaporation is carried out at a higher temperature for a long time, and the whole continuous production is realized, so that the fluctuation of the polymerization degree of the product is small, and the obtained polydextrose has a uniform.

Has the advantages that:

the controllability of the polymerization degree of the polydextrose is realized by carrying out polymerization reaction through segmented temperature control, the polydextrose products with different specifications, such as average molecular weight of 2000-8000, polymerization degree of 13-40, polymerization degree of 8-13, polymerization degree of 3-8 and the like and uniform polymerization degree are prepared by adopting a membrane separation technology and a chromatographic separation technology, the fractional production of the polydextrose products is realized by adjusting the time of carrying out polymerization reaction through segmented temperature control, the special requirements of different downstream industries can be met, and the separated glucose is refined and concentrated and then returned to be used as a raw material.

Detailed Description

The technical solution of the present invention is further described with reference to the following examples, but the scope of the present invention is not limited thereto.

The materials and medicines involved in the invention are all common commercial products.

Example 1

The preparation method of the polydextrose with uniform polymerization degree comprises the following steps:

(1) adding water into corn starch to adjust the concentration of the starch slurry to 16 Baume, and adjusting the pH value to 5; obtaining glucose syrup with the stationary content of 80% through liquefaction, saccharification and concentration;

(2) adding 8% of sorbitol and 1.5% of citric acid into the glucose syrup obtained in the step (1), pumping into a vacuum belt dryer, carrying out polymerization reaction at 140 ℃ for 24min at the operation speed of 120 min/week, carrying out polymerization reaction at 155 ℃ for 48min, and cooling at 35 ℃ for 48min to obtain crude polydextrose with the content of 95%;

(3) and (3) crushing the crude polydextrose obtained in the step (2), adding water for dissolving, decoloring and filtering, feeding into an integrated membrane device, respectively performing membrane separation by using nanofiltration membranes with molecular cut-off of 2500, 1500 and 1000, and performing chromatographic separation to obtain the high-uniformity polydextrose.

In the highly uniform polydextrose product prepared in the example, polydextrose with a polymerization degree of 13-40 accounts for 70% by mass (calculated on a dry basis), has a purity of 93.8% and an average molecular weight of 3000; polydextrose with polymerization degree of 8-13, mass ratio of 20% (dry basis), purity of 94.1%, and average molecular weight of 2000; polydextrose with a degree of polymerization of 3-8, a purity of 95.3%, a mass fraction of 7% (on a dry basis), an average molecular weight of 1000; 3 percent of glucose syrup and sorbitol mixture by mass percent are returned to be used as raw materials.

Example 2

The preparation method of the polydextrose with uniform polymerization degree comprises the following steps:

(1) adding water into the cassava starch to adjust the concentration of the starch slurry to 17 Baume, and adjusting the pH value to 5; obtaining glucose syrup with the fixture content of 85 percent through liquefaction, saccharification and concentration;

(2) adding 2% sorbitol and 0.5% citric acid into the glucose syrup obtained in the step (1), pumping into a vacuum belt dryer, wherein the running speed of the vacuum belt dryer is 60 min/week, carrying out polymerization reaction at 142 ℃ for 12min, then carrying out polymerization reaction at 158 ℃ for 24min, and finally cooling at 32 ℃ for 24min to obtain crude polydextrose with the content of 97%;

(3) and (3) crushing the crude polydextrose obtained in the step (2), adding water to dissolve, decoloring and filtering, feeding into an integrated membrane device, respectively performing membrane separation by using nanofiltration membranes with molecular cut-off of 3000, 2500 and 1500, and performing chromatographic separation to obtain the high-uniformity polydextrose.

In the highly uniform polydextrose product prepared in the example, polydextrose with a polymerization degree of 13-40 accounts for 20% by mass (calculated on a dry basis), has a purity of 93.8% and an average molecular weight of 2500; polydextrose with a polymerization degree of 8-13, a mass ratio of 50% (on a dry basis), a purity of 94.1% and an average molecular weight of 1700; polydextrose with a degree of polymerization of 3-8, a purity of 95.3%, a mass ratio of 25% (on a dry basis), an average molecular weight of 1000; 5 percent of glucose syrup and sorbitol mixture by mass percent are returned to be used as raw materials.

Example 3

The preparation method of the polydextrose with uniform polymerization degree comprises the following steps:

(1) adding water into wheat starch to adjust the concentration of the starch slurry to 16 Baume, and adjusting the pH value to 5; obtaining glucose syrup with the fixture content of 83 percent through liquefaction, saccharification and concentration;

(2) adding 10% sorbitol and 1% citric acid into the glucose syrup obtained in the step (1), pumping into a vacuum belt dryer, wherein the running speed of the vacuum belt dryer is 90 min/week, carrying out polymerization reaction at 130 ℃ for 18min, then carrying out polymerization reaction at 160 ℃ for 36min, and finally cooling at 37 ℃ for 36min to obtain crude polydextrose with the content of 98%;

(3) and (3) crushing the crude polydextrose obtained in the step (2), adding water for dissolving, decoloring and filtering, feeding into an integrated membrane device, respectively performing membrane separation by using nanofiltration membranes with molecular cut-off of 2500, 1500 and 1000, and performing chromatographic separation to obtain the high-uniformity polydextrose.

The procedures of liquefaction, saccharification, decolorization filtration and chromatographic separation are the same as in example 1.

In the highly uniform polydextrose product prepared in the example, polydextrose with a polymerization degree of 13-40 accounts for 40% by mass (calculated on a dry basis), has a purity of 93.8% and an average molecular weight of 2800; polydextrose with a polymerization degree of 8-13, a mass ratio of 30% (on a dry basis), a purity of 94.1% and an average molecular weight of 2000; polydextrose with a polymerization degree of 3-8, a mass percentage of 26% (dry basis), a purity of 95.3% and an average molecular weight of 1000; 4 percent of glucose syrup and sorbitol mixture by mass percent are returned to be used as raw materials.

Comparative example 1

The preparation method of polydextrose comprises the following specific steps of example 1, wherein the difference is that the step (2) comprises: adding 8% sorbitol and 1.5% citric acid into the glucose syrup obtained in step (1), pumping into a vacuum belt dryer with the running speed of 120 min/week, performing polymerization reaction at 130 deg.C for 80min, and cooling at 40 deg.C for 40 min.

The molecular weight distribution of the polydextrose product prepared by the comparative example is 180-1500, and the distribution of the polymerization degree is 1-10; the residual glucose amount was 20%.

Comparative example 2

The preparation method of polydextrose comprises the following specific steps of example 1, wherein the difference is that the step (2) comprises: adding 8% sorbitol and 1.5% citric acid into the glucose syrup obtained in step (1), pumping into a vacuum belt dryer with the running speed of 80 min/week, performing polymerization reaction at 160 deg.C for 80min, and cooling to room temperature.

The molecular weight of the polydextrose product prepared by the comparative example is 180-16000, the distribution of polymerization degree is 1-100, the mass ratio of polydextrose with polymerization degree over 40 is more than 60%, and the color is dark.

As can be seen from the products prepared in the above examples 1-3 and comparative examples 1-2, the polymerization degree of the product is smaller and the glucose residue is more in comparative example 1 because the reaction is carried out at a low temperature of 130 ℃ in the whole process; comparative example 2 was reacted throughout at a high temperature of 160 c, causing the product to over polymerize, dark in color, and produce much caramel. The method adopted in the embodiments 1 to 3 enables the materials to form a film on production equipment, the materials move forward at a constant speed, the reaction conditions of the materials are consistent, partial polymerization mainly based on evaporation is performed for a short time by controlling the reaction temperature, then main polymerization is performed for a long time, continuous production is formed, the fluctuation of the polymerization degree of the final product is small, and the polymerization degree of the obtained polydextrose is uniform.