CN114736940A - Preparation method of amylose with different chain lengths - Google Patents

Abstract

The invention belongs to the technical field of food processing, and discloses a preparation method of amylose with different chain lengths. and centrifuging, discarding the supernatant to obtain a starch precipitate; (2) configuring the starch precipitate into a 10%-20% starch dispersion liquid, and performing thermal shearing treatment at 80-120 ° C; (3) heat The starch dispersion liquid after shearing treatment is subjected to thermal centrifugation treatment at the same thermal shearing temperature, and the supernatant liquid and the precipitate are collected respectively to obtain amylose with a specific chain length distribution. The present invention obtains short amylose fractions with different chain length distributions by screening and grading by centrifugation at different temperatures, and compresses the time consumed by the currently mainstream precipitation step-by-step grading method to within a few hours. Simple, short-term, high-efficiency and environmentally friendly, it is beneficial to the industrial production of amylose with different chain lengths.

Description

A kind of preparation method of different chain length amylose

technical field

The invention relates to the fields of food processing technology, chemical industry and medicine, in particular to a method for preparing short and short amylose with different chain lengths with simple operation and high efficiency.

Background technique

As a rich natural resource in my country, starch is an important raw material for many industries such as food industry and pharmaceutical industry. How to make good use of starch resources has also become an important issue in the food industry. Therefore, the deep processing of starch is the key to optimizing its resource allocation efficiency. As the enzymatic hydrolysis product of starch, short amylose has important applications in both food and medicine. Due to its different chain length distribution and wide molecular weight distribution, its own properties and functions are different. Short amylose with a specific chain length has its superior spatial helical structure, which can form a stable carrier with lipids to encapsulate the drug and improve the delivery efficiency of the drug, and the complexing ability with fatty acids depends on its chain length (Nuengmaysa, Klaochanpong, Chureerat Puttanlek). , Vilai Rungsardthong, et al. Physicochemical and structural properties of debranched waxy rice, waxycorn and waxy potato starches [J]. Food Hydrocolloids, 2015, 45.). For example, the entrapment efficiency of short amylose with an average DP of 34 for arachidonic acid is significantly better than that of short amylose with an average DP of 22 (Zhan Wei, Yuan Chao, Cui Bo, et al. Effect of chain length on the structure and physicochemical properties of active compound/linear dextrin composites [J]. Carbohydrate Polymers, 2021, 269.). Therefore, obtaining short amylose with a specific chain length distribution is a key common problem to be solved in starch processing applications.

The methods of short amylose classification at home and abroad mainly include size exclusion chromatography and solvent precipitation stepwise classification. Chromatography is not only expensive for packing materials and separation devices, but also difficult to enter into industrial production due to the small amount of processing. The stepwise classification method of solvent precipitation mainly has two precipitants: ethanol and polyethylene glycol: the former will lead to low separation efficiency due to local co-precipitation phenomenon and classification temperature sensitivity, while the latter requires at least one day and A large number of polyethylene glycol reagents have the disadvantages of taking a long time and consuming a large amount of organic reagents. At the same time, the solvent precipitation step-by-step grading method needs to remove the residual precipitant in the graded starch to increase the separation steps and increase the difficulty of operation, resulting in cumbersome and inconvenient operation.

SUMMARY OF THE INVENTION

In view of the current methods for preparing short amylose starches with different chain lengths, the classification time is long, the classification efficiency is low, the organic solvent consumption is large and the operation is cumbersome, which limits its scale in the industrial field. The purpose of the present invention is to provide a kind of simple operation, A grading method for efficient screening of short amylose starches with different chain lengths. The simple, energy-saving and high-efficiency preparation of amylose with different chain lengths and short amyloses can be realized by different chain length starches under different temperature and centrifugal force conditions.

The object of the present invention is achieved through the following technical solutions:

A preparation method of amylose with different chain lengths, comprising the following steps:

(1) debranching the gelatinized starch with debranching enzyme, cooling the obtained debranched starch paste to fully regenerate, and centrifuging, discarding the supernatant to obtain a starch precipitate;

(2) configuring the starch precipitate obtained in step (1) into a 10%-20% (w/v) starch dispersion, and performing thermal shearing treatment at 80-120°C;

(3) the starch dispersion liquid after the thermal shearing treatment obtained in step (2) is subjected to thermal centrifugation at the same thermal shearing temperature, and the supernatant liquid and the precipitate are collected respectively to obtain a straight chain with a specific chain length distribution. starch.

Preferably, it also includes step (4) step-by-step screening I: the precipitate obtained in step (3) is subjected to thermal shearing and thermal centrifugation in steps (2) and (3) for at least one time, and the precipitate is collected. Further amylose with a specific chain length distribution is obtained.

Preferably, it also includes step (4) step-by-step screening II: cooling the supernatant obtained in step (3) to fully regenerate, repeating the thermal shearing and thermal centrifugation of steps (2) and (3) at least once, and collecting the precipitate The amylose with a specific chain length distribution can be further obtained.

Preferably, the thermal shear temperature in step (3) and the step-by-step screening I increases successively, and the thermal shear temperature in step (3) and the step-by-step screening II decreases successively.

Preferably, the thermal shear treatment is to shear the starch milk at a rotation speed of 350±50r/min during the heating process for 30±10min.

Preferably, the centrifugal force of the centrifugal treatment in steps (1) (3) (4) is successively reduced.

Preferably, the centrifugal force of the centrifugation described in steps (1) (3) (4) is 5000-500×g, and the centrifugation time is 10±5min.

Preferably, the starch paste in step (1) and the supernatant in step (4) in step-by-step screening II are cooled to below 20°C for retrogradation for 1 hour.

Preferably, the preparation of the debranched starch paste in step (1): adding water to starch to make 5-20% starch milk, and heating for gelatinization; then reducing the temperature of the starch paste to an enzyme-friendly temperature, adjusting the pH and adding The debranched starch paste is obtained by enzymatic hydrolysis with pullulanase.

Preferably, the starch is potato starch, corn starch, soybean starch, and wheat starch.

The heating and shearing temperature or centrifugation temperature of the present invention is preferably 80-120°C. The set temperature should not be too high. If the temperature is too high, the disintegration of starch aggregates will easily occur, resulting in centrifugation to the supernatant; if the temperature is too low, the screening of different chain lengths will not be specific. In addition, the temperature of each screening should be gradually increased or decreased. When performing step (1) (2) (3) (4) step by step screening I, the thermal shear temperature gradually increases with the screening times, on the one hand, it can destroy the starch aggregates with low phase transition temperature, and on the other hand, it can improve the high temperature. Phase transition temperature thermal stability and average chain length of starch aggregates. See embodiment 5 and Fig. 1, when screening temperature rises gradually, the branching degree of the starch molecule that obtains reduces step by step, and amylose content and average polymerization degree increase step by step, can significantly increase the chain length in graded starch. And obtain amylose with longer chain length distribution. When performing step (1) (2) (3) (4) step by step screening II, the thermal shear temperature gradually decreases with the screening times, and at the same time, the centrifugal force is gradually reduced for centrifugal treatment, which can separate the amylose or starch with shorter chain length. Small branched amylopectin. Further, the amylose content and branching degree in the graded starch can be controlled, and amylose with different chain lengths can be finally prepared. See Example 6 and Fig. 2, when the screening temperature gradually decreased, the branching degree of the obtained starch molecules increased step by step, and the amylose content and the average degree of polymerization decreased step by step, so that the average chain length gradually decreased and branched. The amylose component of increasing degree.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) The present invention carries out screening and grading by centrifugation at different temperatures to obtain short amylose fractions with different chain length distributions, and compresses the time taken by the precipitation step-by-step grading method currently used in the mainstream to several hours In addition, the method is simple, time-consuming and efficient, which is beneficial to the industrial production of short amylose starch with different chain lengths.

(2) The present invention completely replaces the precipitant organic reagent consumed by the traditional method of precipitation and grading with clean resource water, solves the problem that the residual organic solvent in the starch needs to be cleaned and removed after each grading, and improves the safety performance of screening starch. , simplifies the operation steps of short amylose screening, and can be widely used in the field of deep processing of starch resources.

Description of drawings

FIG. 1 is a graph showing the thermal gelatinization curves of amylose with different chain lengths prepared in Example 5. FIG.

FIG. 2 is a graph showing the thermal gelatinization curves of amylose with different chain lengths prepared in Example 6. FIG.

Detailed ways

For better understanding of the present invention, the present invention will be further described below through examples. The present invention has many successful embodiments, 6 specific embodiments are listed below, including 2 stepwise screening embodiments, but the claimed scope of the present invention is not limited to the scope expressed by the embodiments.

In the examples of the present invention, refer to the method of Oluwaseun et al. (Arijaje Emily, Oluwaseun, Wang Ya-Jane. Effects of chemical and enzymatic modifications onstarch-oleic acid complex formation. [J]. Journal of agricultural and food chemistry, 2015 , 63 (16).), wherein all raw materials such as potato starch, pullulanase, sodium hydroxide solution etc. are all commonly used materials by those skilled in the art, and the specific preparation debranched starch paste process is as follows:

Weigh 180g (dry basis) potato starch, add 1800mL deionized water to prepare 10% starch milk, gelatinize in a 100°C water bath for 60min; then reduce the temperature of the starch paste to 55°C, adjust the pH to 5.0, add 150U/ G starch was hydrolyzed by pullulanase for 12h; the pH was adjusted to about 7.0 with sodium hydroxide aqueous solution to stop the reaction, and the enzyme was inactivated at 100°C for 60min, to obtain the debranched starch after debranching and inactivation of the debranching enzyme paste.

Example 1

(1) Cool the debranched starch paste after debranching and inactivating the enzyme with debranching enzyme to 20°C for full regeneration for 1 hour, and centrifuge at 5000 × g for 10 minutes, discard the supernatant to obtain starch precipitate;

(2) configuring the starch precipitation obtained in step (1) into a 10% (w/v) starch dispersion, and heat shearing for 30 minutes at 85° C. and a rotating speed of 350 r/min in a constant temperature water bath;

(3) Centrifuge the starch dispersion liquid obtained in step (2) at the same thermal shear temperature (85° C.) under a centrifugal force of 4500 × g for 10 min, discard the supernatant, and collect the precipitate, that is, the straight chain with a specific chain length distribution. chain starch.

The starch precipitate in step (1) was thermodynamically analyzed by differential scanning calorimeter, and its thermal gelatinization parameters were shown in Table 1, and the step ( 3) The collected starch precipitates were analyzed for branching degree, amylose content and chain length distribution. As can be seen from Table 1, the starch precipitate in step (1) has three phase transition peaks, among which Peak I (phase transition range 84.46-94.90°C), Peak II (phase transition range 96.79-106.04°C) and Peak III (phase transition range 96.79-106.04°C) Range of 109.78-129.28℃) heat absorption peak, indicating that there are amylose aggregates with different thermal stability, so setting thermal shear and thermal centrifugation temperature can separate starch aggregates with different phase transition temperatures, and the separated starch precipitates The degree of branching was 7.36%, the content of amylose was 53.16%, and the average degree of polymerization was 23.85. This shows that the short-term retrogradation of starch and the difference in thermal stability of the aggregates can be used to screen, and the target average DP23.85 amylose can be isolated, and the thermal shearing and thermal centrifugation temperature are the best way to prepare amylose with a specific chain length distribution. key.

Table 1

Example 2

(1) Cool the debranched starch paste after debranching and inactivating the enzyme with debranching enzyme to 20°C for full regeneration for 1 hour, and centrifuge at 5000 × g for 10 minutes, discard the supernatant to obtain starch precipitate;

(2) configuring the starch precipitation obtained in step (1) into a 15% (w/v) starch dispersion, and heat shearing for 30min at 95°C and 350r/min rotating speed in a constant temperature water bath;

(3) Centrifuge the starch dispersion liquid obtained in step (2) under the same thermal shear temperature (95° C.) under a centrifugal force of 4500 × g for 10 min, discard the supernatant, and collect the precipitate, that is, the short-term distribution of the specific chain length. Amylose. The obtained starch precipitation thermal gelatinization parameters are shown in Table 2. It can be seen that there are two heat absorption peaks, Peak I (phase transition range 76.42-98.54°C) and Peak II (phase transition range 105.87-129.38°C) heat absorption peaks. The isolated starch precipitate has a branching degree of 5.63%, an amylose content of 59.43% and an average degree of polymerization of 26.23.

Table 2

Example 3

(1) Cool the debranched starch paste after debranching and inactivating the enzyme with debranching enzyme to 20°C for full regeneration for 1 hour, and centrifuge at 5000 × g for 10 minutes, discard the supernatant to obtain starch precipitate;

(2) configuring the starch precipitation obtained in step (1) into a 15% (w/v) starch dispersion, and heat shearing for 30min at 105°C and 350r/min rotating speed in a constant temperature water bath;

(3) Centrifuge the starch dispersion liquid obtained in step (2) under a centrifugal force of 4500 × g for 10 min at the same thermal shear temperature, discard the supernatant, and collect the precipitate, that is, short amylose starch with a specific chain length distribution. The obtained starch precipitation thermal gelatinization parameters are shown in Table 3. It can be seen that there are two heat absorption peaks, Peak I (phase transition range 73.35-81.46°C) and Peak II (phase transition range 109.92-137.34°C) heat absorption peaks. The isolated starch precipitate had a branching degree of 4.64%, an amylose content of 61.03%, and an average degree of polymerization of 28.12.

table 3

Example 4

(1) Cool the debranched starch paste after debranching and inactivating the enzyme with debranching enzyme to 20°C for full regeneration for 1 hour, and centrifuge at 5000 × g for 10 minutes, discard the supernatant to obtain starch precipitate;

(2) configuring the starch precipitation obtained in step (1) into a 20% (w/v) starch dispersion, and heat shearing for 30min at 115°C and 350r/min rotating speed in a constant temperature water bath;

(3) Centrifuge the starch dispersion liquid obtained in step (2) under a centrifugal force of 4500 × g for 10 min at the same thermal shear temperature, discard the supernatant, and collect the precipitate, that is, short amylose starch with a specific chain length distribution. The obtained starch precipitation thermal gelatinization parameters are shown in Table 4. It can be known that there are two heat absorption peaks, Peak I (phase transition range 62.68-75.66°C) and Peak II (phase transition range 108.68-139.83°C) heat absorption peaks. The isolated starch precipitate had a branching degree of 4.49%, an amylose content of 62.15%, and an average degree of polymerization of 29.12.

Table 4

Example 5

(1) Cool the debranched starch paste after debranching and inactivating the enzyme with debranching enzyme to 20°C for full regeneration for 1 hour, and centrifuge at 5000 × g for 10 minutes, discard the supernatant to obtain starch precipitate;

(2) configuring the starch precipitation obtained in step (1) into a 15% (w/v) starch dispersion, and heat shearing for 30min at 90°C and 350r/min rotating speed in a constant temperature water bath;

(3) Centrifuge the starch dispersion liquid obtained in step (2) at a centrifugal force of 4390×g for 10 min at the same thermal shear temperature, and collect the precipitate, that is, short amylose starch with a specific chain length distribution.

(4) reconfigure the precipitate obtained in step (3) into a starch dispersion liquid, repeat the thermal shearing and thermal centrifugation of steps (2) and (3) three times, wherein the temperatures are 100° C., 110° C. and 120° C. , the corresponding centrifugal forces are 2809×g, 1580×g and 702×g. The amylose with a specific chain length distribution can be further obtained. The branching degrees of the isolated four groups of starch precipitates were 7.12%, 4.83%, 4.39% and 4.29%, the amylose contents were 52.11%, 61.13%, 62.23% and 63.37%, and the average degrees of polymerization were 24.94, 28.17, 29.62 and 30.81. This shows that the aggregation behavior of starch short-term retrogradation and the difference in thermal stability of the aggregates can be screened, and with the stepwise increase of the treatment temperature, the branching degree decreases step by step, while the amylose content and the average degree of polymerization increase step by step. increase. Therefore, thermal shearing and thermal centrifugation temperature are the keys to prepare short amylose with specific chain length distribution, and amylose fractions with gradually increasing average chain lengths were screened out.

Example 6

(1) Cool the debranched starch paste after debranching and inactivating the enzyme with debranching enzyme to 20°C for full regeneration for 1 hour, and centrifuge at 5000 × g for 10 minutes, discard the supernatant to obtain starch precipitate;

(2) configuring the starch precipitation obtained in step (1) into a 15% (w/v) starch dispersion, and heat shearing for 30min at 110°C and 350r/min rotating speed in a constant temperature water bath;

(3) the starch dispersion liquid obtained in step (2) is centrifuged at 4390 × g centrifugal force for 10 min at the same thermal shear temperature, and the supernatant and the precipitate are collected, wherein the precipitate is a short straight chain with a specific chain length distribution starch.

(4) cooling the supernatant obtained in step (3) to 20° C. for full regeneration for 1 h and reconfiguring it into a starch dispersion, repeating the thermal shearing and thermal centrifugation of steps (2) and (3) three times, wherein the temperature They are 100°C, 90°C and 80°C in sequence, and the corresponding centrifugal forces are 2809×g, 1580×g and 702×g. After collecting the precipitate, starch components with specific chain length distribution can be further obtained.

The branching degrees of the isolated four groups of starch precipitates were 7.56%, 9.23%, 10.56% and 12.68%, the amylose contents were 41.17%, 36.03%, 28.53% and 18.32%, and the average degree of polymerization was 24.15. , 22.87, 20.13 and 19.51. This indicates that the aggregation behavior of starch short-term retrogradation and the difference in thermal stability of the aggregates can be screened, and with the stepwise decrease of the treatment temperature, the branching degree increases step by step, while the amylose content and the average degree of polymerization increase step by step. reduce. Therefore, thermal shearing and thermal centrifugation temperature are the keys to the preparation of short amylose with specific chain length distribution, and the amylose fractions with gradually decreasing average chain length and increasing branching degree were screened out.

Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the present invention; any modifications, substitutions, combinations and improvements made within the spirit and principles of the present invention, etc., All should be included within the protection scope of the claims of the present invention.

Claims (10)

1. a preparation method of different chain length amylose, is characterized in that, comprises the following steps: (1) debranching the gelatinized starch with debranching enzyme, cooling the obtained debranched starch paste to fully regenerate, and centrifuging, discarding the supernatant to obtain a starch precipitate; (2) configuring the starch precipitate obtained in step (1) into a 10%-20% (w/v) starch dispersion, and performing thermal shearing treatment at 80-120°C; (3) the starch dispersion liquid after the thermal shearing treatment obtained in step (2) is subjected to thermal centrifugation at the same thermal shearing temperature, and the supernatant liquid and the precipitate are collected respectively to obtain a straight chain with a specific chain length distribution. starch. 2. method according to claim 1, is characterized in that, also comprises step (4) step by step screening I: the precipitate obtained by step (3), repeats the thermal shearing of steps (2) and (3), Thermal centrifugation is performed at least once, and the precipitate is collected, ie further amylose with a specific chain length distribution is obtained. 3. method according to claim 1, is characterized in that, also comprises step (4) step by step screening II: the supernatant liquid cooling that step (3) obtains is fully regenerated, repeats step (2) and (3) Thermal shearing and thermal centrifugation are performed at least once, and the precipitate is collected, that is, amylose with a specific chain length distribution is further obtained. 4. The method according to any one of claims 1 to 3, wherein the thermal shear temperature in step (3) and the step-by-step screening I increases successively, and the step (3) and the step-by-step screening II in The thermal shear temperature is decreased successively. 5. The method according to claim 4, characterized in that, the thermal shearing treatment is that the heating process shears the starch milk at a rotating speed of 350±50r/min, and the time is 30±10min. 6. The method according to any one of claims 1 to 3, wherein the centrifugal force of the centrifugal treatment in steps (1) (3) (4) is successively reduced. 7 . The method according to claim 6 , wherein the centrifugal force of the centrifugation described in the steps (1) (3) and (4) is 5000-500×g, and the centrifugation time is 10±5min. 8 . 8. The method according to any one of claims 1 to 3, wherein the starch paste in step (1) and the supernatant in step (4) step-by-step screening II are cooled to below 20°C for 1 hour of retrogradation. 9. The method according to any one of claims 1 to 3, wherein the preparation of the debranched starch paste in step (1): adding water to starch to make 5-20% starch milk, and heating to gelatinize Then, the temperature of the starch paste is lowered to the optimum temperature for the enzyme, the pH is adjusted, and pullulanase is added for enzymatic hydrolysis to obtain a debranched starch paste. 10. The method according to claim 9, wherein the starch is potato starch, corn starch, soybean starch, and wheat starch.

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