Method for preparing starch-lipid compound based on induced electric field

Abstract

The invention relates to the field of food and starch processing, and discloses a preparation method for preparing a starch-lipid compound based on an induced electric field. The preparation method of the starch-lipid compound mainly comprises the following steps: taking starch as a raw material, carrying out pullulanase debranching treatment to obtain debranched starch, and preparing the starch-lipid compound from the debranched starch and lipid in the presence of an induced electric field. The induction electric field technology is adopted for assistance, the preparation efficiency is greatly improved, the defects of chemical reagent residues and large high-temperature energy consumption of an existing preparation method are overcome, the preparation method is environmentally friendly and efficient, and the obtained product is high in safety and more suitable for application in the fields of food and the like.

Description

Technical Field

[0001] The invention relates to the field of food and starch processing, and in particular to a method for preparing a starch-lipid complex based on an induced electric field. Background Art

[0002] Amylose has a helical structure and contains hydrophobic cavities, into which fatty acids can enter or the carboxyl groups contained in fatty acids react with the hydroxyl groups of starch to form ester bonds, which then adhere to the surface of starch particles and wrap up the entire starch particle, thus forming a starch-fatty acid complex. The stable helical structure makes the starch-lipid complex have lower solubility and swelling, higher thermal stability and digestibility. These excellent properties give the starch-lipid complex a unique advantage in improving the body's blood sugar metabolism, preventing intestinal diseases and improving human sub-health.

[0003] At present, starch-lipid complexes are usually prepared by compounding starch with organic acids or lipids. The main methods are: extrusion cooking, steam jet cooking, ultra-high pressure treatment, phosphorylase catalytic synthesis, dimethyl sulfoxide method and acid-base precipitation method. Some of these synthesis methods are preparation methods with low compounding rate, low production efficiency and damage to starch granule structure, such as extrusion cooking and steam jet cooking; some are methods with high equipment requirements and difficult continuous production, such as ultra-high pressure treatment; some are preparation methods with complex production processes and produce a large amount of industrial waste liquid to pollute the environment, such as phosphorylase catalytic synthesis, dimethyl sulfoxide method and acid-base precipitation method. Therefore, there is an urgent need for a low-energy consumption, low-cost, green and efficient synthesis method to enable the complex to be widely promoted and applied. Summary of the invention

[0004] In view of the problems and shortcomings in the prior art, the purpose of the present invention is to provide a method for preparing starch-lipid complexes based on an induced electric field.

[0005] Based on the above purpose, the present invention adopts the following technical solution:

[0006] The first aspect of the present invention provides a method for preparing a starch-lipid complex, which specifically comprises the following steps:

[0007] S1: Preparation of debranched starch: starch is made into a starch suspension, which is then sterilized under high pressure to gel the starch suspension, the gelled starch suspension is cooled, pullulanase is added after cooling and stirred to carry out a debranching reaction, after the reaction is completed, the pH of the reaction system is adjusted to 7 and boiled, after boiling, the temperature is cooled and centrifuged to obtain a precipitate, the precipitate is washed with hot ethanol, the washed precipitate is freeze-dried, ground and sieved to obtain debranched starch.

[0008] S2: Preparation of starch lipid complex: the debranched starch obtained above is made into a homogenate, and then lipid is added and stirred. After stirring evenly, the mixture is heated, and then the reaction system is pumped into an induced electric field for treatment. After the treatment, the mixture is cooled. After cooling, the mixture is stirred and centrifuged to obtain a precipitate. The precipitate is washed with hot ethanol. The washed precipitate is freeze-dried, ground, and sieved to obtain a starch lipid complex.

[0009] Preferably, the lipid in step S2 is any one or more of palmitic acid, stearic acid and oleic acid.

[0010] Preferably, the lipid in step S2 is stearic acid.

[0011] Preferably, the stirring time in step S1 is 10-14 hours.

[0012] Preferably, the enzyme inactivation method in step S1 is boiling for 15 minutes.

[0013] Preferably, the concentration of the starch suspension in step S1 is 50-100 g / L.

[0014] Preferably, the starch suspension is prepared by adding sodium acetate buffer to starch.

[0015] Preferably, the concentration of the sodium acetate buffer is 0.2 mol / L.

[0016] Preferably, the pullulanase added in step S1 is 10-100u / g starch.

[0017] Preferably, in step S2, the excitation voltage of the induced electric field is 150-300V, the frequency is 400-700Hz, the processing time is 1-2h, and the rotation speed of the pump is 30-50rpm.

[0018] Preferably, the concentration of the homogenate in step S2 is 50-100 g / L.

[0019] Preferably, the homogenate in step S2 is prepared by adding sodium acetate buffer to debranched starch.

[0020] Preferably, the concentration of the sodium acetate buffer is 0.2 mol / L.

[0021] Preferably, the amount of lipid added in step S2 is 5-10% of the mass of the starch in step S1.

[0022] Preferably, the heating temperature in step S2 is 80-90°C.

[0023] Preferably, the cooling in step S1 is cooling to 60°C.

[0024] Preferably, in step S1, adjusting the pH value of the reaction system to 7 is performed by using a NaOH solution.

[0025] Preferably, the concentration of the NaOH solution is 10%.

[0026] Preferably, the concentration of the hot ethanol in step S1 is 50%.

[0027] Preferably, the washing times in step S1 are 3-4 times.

[0028] Preferably, the sieving in step S1 is a 100 mesh sieve.

[0029] Preferably, the hot ethanol concentration in step S2 is 50%.

[0030] Preferably, the washing times in step S2 are 3-4 times.

[0031] Preferably, the sieving in step S2 is a 100 mesh sieve.

[0032] Preferably, the starch in step S1 is any one or more of corn starch, potato starch, high-amylose corn starch, sweet potato starch, rice starch, and tapioca starch.

[0033] Preferably, the starch in step S1 is high-amylose corn starch.

[0034] The second aspect of the present invention provides a starch-lipid complex prepared by the method described in the first aspect.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The present invention uses induced electric field technology to assist in the preparation of starch lipid complexes. Compared with the traditional preparation method, the preparation efficiency is greatly improved, the composite rate of the obtained starch lipid complex can be increased to 97.13%, and the swelling degree and solubility of the prepared starch lipid complex are reduced. XRD and FTIR results show that the short-range order of the starch lipid complex molecules prepared with the assistance of induced electric field is improved, 1047cm- 1 / 1022cm-1 values ​​are greater than those of the control group. Digestibility is greatly improved, and the content of resistant starch increases significantly, reaching 39.49%. Starch lipid complexes can assist in regulating sugar metabolism, lipid metabolism, and improving the intestinal environment, and have great application value in the fields of food, medicine, functional health food, etc.

[0037] (2) The induced electric field technology used in the present invention utilizes the principle of electromagnetic induction to excite the conductive liquid sample in a closed loop with an alternating magnetic field, thereby inducing an induced electric field inside the medium, thereby realizing non-contact electric field treatment. Compared with the prior art, the present invention overcomes the shortcomings of the prior art preparation method, such as the cumbersome processing process, the presence of chemical reagent residues, and high-temperature energy consumption. It is a green and efficient preparation method, and the resulting product is highly safe and more suitable for applications in the food and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a composite index result graph of high amylose corn starch-stearic acid complexes obtained in Examples 1 to 3 and Comparative Examples 1 to 3;

[0039] Figure 2 is the X-ray diffraction pattern of the high amylose corn starch-stearic acid complex obtained in Examples 1 to 3 and Comparative Examples 1 to 3;

[0040] Figure 3 It is the Fourier transform infrared spectroscopy analysis of the high amylose corn starch-stearic acid complex obtained in Examples 1 to 3 and Comparative Examples 1 to 3. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail by way of embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0042] Example 1

[0043] This embodiment provides a method for preparing a high-amylose corn starch-stearic acid complex, which specifically comprises the following steps:

[0044] S1: Preparation of debranched starch: Mix high-amylose corn starch with 0.2 mol / L sodium acetate buffer (pH==5.0) to form 8g / 100mL starch suspension, and then treat it in an autoclave at 121°C for 30 minutes to fully gelatinize the starch. Cool the gelatinized starch paste to 60°C, add pullulanase (60U / g starch), and stir for 12 hours to debranch it. Adjust the solution pH to 7 with 0.1 mol / L NaOH and boil for 15 minutes. After cooling, centrifuge to obtain a precipitate, wash it three times with 50% hot ethanol, freeze-dry the washed precipitate, grind it, and pass it through a 100-mesh sieve to obtain debranched starch.

[0045] S2: Preparation of starch lipid complex: prepare debranched starch slurry with sodium acetate buffer, add 8% stearic acid of starch dry basis weight and stir evenly, place the starch paste in a water bath, set the temperature to 85°C, pump the starch milk into the induced electric field with a peristaltic pump at a speed of 40rpm, an excitation voltage of 200V, and a frequency of 500Hz. Treat for 1.5h, continue stirring for 1h after cooling, centrifuge at 8000r / min for 30min, wash three times with 50% hot ethanol, freeze-dry the precipitate after washing, grind, and pass through a 100-mesh sieve to obtain a high-amylose corn starch-stearic acid complex.

[0046] Example 2

[0047] This embodiment provides a method for preparing a high-amylose corn starch-stearic acid complex, which specifically comprises the following steps:

[0048] S1: Preparation of debranched starch: Mix high-amylose corn starch with 0.2mol / L sodium acetate buffer (pH=5.0) to form a 5g / 100mL starch suspension, and then treat it in an autoclave at 121°C for 30min to fully gelatinize the starch. Cool the gelatinized starch paste to 60°C, add pullulanase (10U / g starch), and stir for 10h to debranch it. Adjust the solution pH to 7 with 0.1mol / LNaOH and boil for 15min. After cooling, centrifuge to obtain a precipitate, wash it 3 times with 50% hot ethanol, freeze-dry the washed precipitate, grind it, and pass it through a 100-mesh sieve to obtain debranched starch.

[0049] S2: Preparation of starch lipid complex: prepare debranched starch slurry with sodium acetate buffer, add 8% stearic acid of starch dry basis weight and stir evenly, place starch paste in a water bath, set the temperature to 80°C, pump starch milk into the induced electric field with a peristaltic pump at a speed of 40 rpm, an excitation voltage of 150 V, and a frequency of 400 Hz. Treat for 1 hour, continue stirring for 1 hour after cooling, centrifuge at 8000 r / min for 30 minutes, wash 3 times with 50% hot ethanol, freeze-dry the precipitate after washing, grind, and pass through a 100-mesh sieve to obtain a high-amylose corn starch-stearic acid complex.

[0050] Example 3

[0051] This embodiment provides a method for preparing a high-amylose corn starch-stearic acid complex, which specifically comprises the following steps:

[0052] S1: Preparation of debranched starch: Mix high-amylose corn starch with 0.2mol / L sodium acetate buffer (pH=5.0) to form a 10g / 100mL starch suspension, and then treat it in an autoclave at 121°C for 30min to fully gelatinize the starch. Cool the gelatinized starch paste to 60°C, add pullulanase (100U / g starch), and stir for 14h to debranch it. Adjust the solution pH to 7 with 0.1mol / LNaOH and boil for 15min. After cooling, centrifuge to obtain a precipitate, wash it 3 times with 50% hot ethanol, freeze-dry the washed precipitate, grind it, and pass it through a 100-mesh sieve to obtain debranched starch.

[0053] S2: Preparation of starch lipid complex: prepare debranched starch slurry with sodium acetate buffer, add 5% stearic acid of starch dry basis weight and stir evenly, place the starch paste in a water bath, set the temperature to 90°C, pump the starch milk into the induced electric field with a peristaltic pump at a speed of 40 rpm, an excitation voltage of 300 V, and a frequency of 700 Hz. Treat for 2 h, continue stirring for 1 h after cooling, centrifuge at 8000 r / min for 30 min, wash with 50% hot ethanol three times, freeze-dry the washed precipitate, grind, and pass through a 100-mesh sieve to obtain a high-amylose corn starch-stearic acid complex.

[0054] Comparative Example 1

[0055] This comparative example provides a method for preparing a high-amylose corn starch-stearic acid complex, which specifically comprises the following steps:

[0056] S1: Preparation of debranched starch: High-amylose corn starch was mixed with 0.2 mol / L sodium acetate buffer (pH==5.0) to form 8 g / 100 mL starch suspension, and then treated in an autoclave at 121°C for 30 min to fully gelatinize the starch. The gelatinized starch paste was cooled to 60°C, and pullulanase (60 U / g starch) was added and stirred for 12 h to debranch it. The solution pH was adjusted to 7 with 0.1 mol / L NaOH and boiled for 15 min. After cooling to room temperature, centrifuged at 8000 rpm for 20 min to obtain a precipitate, which was washed 3 times with 50% hot ethanol, spread on a watch dish after washing, and placed in a freeze dryer for freeze drying for 24 h. After freeze drying, it was ground and passed through a 100-mesh sieve to obtain debranched high-amylose corn starch.

[0057] S2: Preparation of starch lipid complex: prepare debranched high-amylose corn starch slurry with sodium acetate buffer, add 8% stearic acid on a starch dry basis and stir evenly, place the starch paste in a water bath, set the temperature to 85°C, stir for 1.5 hours, continue stirring for 1 hour after cooling, centrifuge at 8000 r / min for 30 minutes, wash three times with 50% hot ethanol to obtain a starch lipid complex, freeze-dry the washed precipitate, grind it, and pass it through a 100-mesh sieve to obtain a high-amylose corn starch-stearic acid complex.

[0058] Comparative Example 2

[0059] This comparative example provides a method for preparing a high-amylose corn starch-stearic acid complex, which specifically comprises the following steps:

[0060] S1: Preparation of debranched starch: Mix high-amylose corn starch with 0.2 mol / L sodium acetate buffer (pH=5.0) to form a 5 / 100 mL starch suspension, and then treat it in an autoclave at 121°C for 30 minutes to fully gelatinize the starch. Cool the gelatinized starch paste to 60°C, add pullulanase (10U / g starch), and stir for 10 hours to debranch it. Adjust the solution pH to 7 with 0.1 mol / L NaOH and boil for 15 minutes. After cooling to room temperature, centrifuge at 8000 rpm for 20 minutes to obtain a precipitate, wash it with 50% hot ethanol 3 times, spread it on a watch glass after washing, and put it into a freeze dryer for freeze drying for 24 hours. After freeze drying, grind and pass through a 100-mesh sieve to obtain debranched high-amylose corn starch.

[0061] S2: Preparation of starch lipid complex: prepare debranched high-amylose corn starch slurry with sodium acetate buffer, add 8% stearic acid based on the dry weight of starch and stir evenly, place the starch paste in a water bath, set the temperature to 80°C, stir for 1 hour, continue stirring for 1 hour after cooling, centrifuge at 8000r / min for 30 minutes, wash three times with 50% hot ethanol to obtain a starch lipid complex, freeze-dry the washed precipitate, grind it, and pass it through a 100-mesh sieve to obtain a high-amylose corn starch-stearic acid complex.

[0062] Comparative Example 3

[0063] This comparative example provides a method for preparing a high-amylose corn starch-stearic acid complex, which specifically comprises the following steps:

[0064] S1: Preparation of debranched starch: High-amylose corn starch was mixed with 0.2 mol / L sodium acetate buffer (pH=5.0) to form a 10 g / 100 mL starch suspension, and then treated in an autoclave at 121°C for 30 min to fully gelatinize the starch. The gelatinized starch paste was cooled to 60°C, and pullulanase (100 U / g starch) was added and stirred for 14 h to debranch it. The solution pH was adjusted to 7 with 0.1 mol / L NaOH and boiled for 15 min. After cooling to room temperature, centrifuged at 8000 rpm for 20 min to obtain a precipitate, which was washed three times with 50% hot ethanol, spread on a watch dish after washing, and placed in a freeze dryer for freeze drying for 24 h. After freeze drying, it was ground and passed through a 100-mesh sieve to obtain debranched high-amylose corn starch.

[0065] S2: Preparation of starch lipid complex: prepare debranched high-amylose corn starch slurry with sodium acetate buffer, add 10% stearic acid by dry weight of starch and stir evenly, place the starch paste in a water bath, set the temperature to 90°C, stir for 2 hours, continue stirring for 1 hour after cooling, centrifuge at 8000r / min for 30 minutes, wash three times with 50% hot ethanol to obtain starch lipid complex, freeze-dry the washed precipitate, grind, and pass through a 100-mesh sieve to obtain a high-amylose corn starch-stearic acid complex.

[0066] Example 4

[0067] In this example, the composite index, in vitro digestion characteristics, solubility and swelling degree, and crystal structure of the high-amylose corn starch-stearic acid complex obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were tested. The specific testing methods are described as follows.

[0068] 1. Test methods

[0069] 1.1 Determination and calculation method of composite index

[0070] Weigh 0.3g starch lipid complex sample into a 50mL centrifuge tube, and add a certain amount of deionized water to make the total mass of the system reach 5g. Place the centrifuge tube in a boiling water bath for 20min, and shake it intermittently to make the starch lipid complex completely gelatinized. After the gelatinized sample is naturally cooled to room temperature, mix it with 25mL deionized water, vortex mix for 2min, centrifuge at 4000rpm for 15min, take 0.5mL of the supernatant, add 15mL deionized water and 2mL iodine solution (containing 2.0% KI and 1.3% I2 aqueous solution) respectively, mix well, color, and measure the absorbance at 690nm. The starch sample without fatty acids is used as the control group. Calculate the composite index CI according to formula (1):

[0071] CI=(A 对照 -A 样品 )×100 / A 对照Formula (1),

[0072] Where, CI is the composite index, %; A 对照 is the absorbance value of the control group; A 样品 It is the absorbance value of starch-lipid complex.

[0073] 1.2 In vitro digestion characteristics determination and calculation method

[0074] Weigh 200 mg of starch lipid complex in a 250 mL conical flask, add 15 mL of pH 5.2 sodium citrate buffer, shake evenly, quickly add 10 mL of a mixed solution of porcine pancreatic α-amylase (290 U / mL) and saccharifying enzyme (15 U / mL), place in a constant temperature incubator, shake at 37°C and 150 rpm. Take 0.5 mL of the enzymatic hydrolyzate at 20 min and 120 min, add 4 mL of 95% ethanol solution to inactivate the enzyme activity, centrifuge at 4500 rpm for 15 min, take 1 mL of the supernatant, and determine the glucose content by 3,5-dinitrosalicylic acid method (DNS). Calculate the relative contents of rapidly digestible starch (RDS), slowly digestible starch (SDS) and RS in the starch lipid complex according to formula (2) to formula (4):

[0075] RDS / %=((G_20-G_0)×0.9) / W×100 Formula (2),

[0076] SDS / %=((G_120-G_20)×0.9) / W×100 Formula (3),

[0077] RS / %=(W-RDS-SDS) / W×100 Equation (4),

[0078] Wherein, G20 is the mass of glucose released within 20 min of hydrolysis / mg; G120 is the mass of glucose released within 120 min of hydrolysis / mg; G0 is the mass of free glucose before enzymatic hydrolysis / mg; W is the mass of starch lipid complex / mg.

[0079] 1.3 Determination of solubility and swelling

[0080] Weigh 0.6 g starch lipid complex sample and prepare 30 mL 2% suspension with distilled water, boil in boiling water for 30 min, cool, centrifuge at 3000 rpm for 10 min, pour the supernatant into a petri dish, dry at 105 °C to constant weight, and calculate the solubility and swelling degree according to formula (5) and formula (6), respectively:

[0081]

[0082] Wherein, S is solubility, %; Sw is swelling degree, %; m1 is dry weight of supernatant, g; m2 is precipitate weight, g; m0 is dry weight of sample, g.

[0083] 1.4 X-ray diffraction measurement method

[0084] The starch-lipid complex sample was placed in an oven to dry for 24 hours and then placed in an X-ray diffractometer for testing. The test conditions were: Cu-Kα ray, voltage of 40 kV, current of 40 mA, scanning range 2θ of 5°-40°, step length of 0.05°, and step speed of 0.5 s.

[0085] 1.5 Fourier transform infrared spectroscopy analysis method

[0086] The starch lipid complex sample was mixed with potassium bromide at a ratio of 1:100 (w / w), ground and pressed into thin sheets, and then tested in a Fourier transform infrared spectrometer with a scanning range of 500-3500 cm-1, a resolution of 4 cm-1, and 32 scans. With air as the blank background, the sample was collected first and then the background was subtracted to obtain the final spectrum. The 1047 cm -1 / 1022cm -1 The peak intensity ratio is used to evaluate the short-range order of the sample.

[0087] 2. Results Analysis

[0088] 2.1 Composite index of high amylose corn starch-stearic acid complex

[0089] Depend on Figure 1 It can be seen that the results of the starch lipid complex index obtained by the induction electric field assisted preparation are all higher than those of the comparative example. Among them, the composite indexes of Example 1, Example 2, and Example 3 are 97.13%, 92.61%, and 94.76%, all reaching more than 90%. After the starch is treated with the induction electric field, more straight-chain starch is released, and at the same time, the groups of the starch molecules are more easily exposed, which increases the probability of interaction with lipids, thereby promoting the composite of starch lipids and improving the composite efficiency.

[0090] 2.2 In vitro digestibility of high-amylose corn starch-stearic acid complex

[0091] As shown in Table 1, after the induction electric field treatment, the RS starch content in the starch lipid complex sample increased and the RDS content decreased, indicating that the digestibility of the starch lipid complex decreased. The sum of the SDS and RS contents was higher than that in the starch lipid complex without the induction electric field treatment.

[0092] Table 1 In vitro digestibility of different starch-lipid complex samples

[0093]

[0094] 2.3 Solubility and swelling of high amylose corn starch-stearic acid complex

[0095] As shown in Table 2, after the induced electric field treatment, the swelling degree of the starch lipid complex decreased. The formation of the complex reduced the dissolution of amylose and the entry of water molecules, which reduced the swelling degree of starch. At the same time, the hydrophobic effect of lipids hindered the entry of water into the starch granules, inhibited the dissolution and swelling of starch granules, and reduced its solubility. The treatment with the induced electric field reduced the solubility and swelling degree of the complex compared with the absence of the induced electric field. The induced electric field assisted treatment reduced the solubility of the starch lipid complex to less than 3% and the swelling degree to less than 4%.

[0096] Table 2 Solubility and swelling of starch-lipid complexes

[0097]

[0098] 2.4 X-ray diffraction analysis of high amylose corn starch-stearic acid complex

[0099] Depend on Figure 2 It can be seen that there are obvious diffraction peaks near 13° and 20°, showing a typical V-shaped crystal structure, indicating that lipids have entered the helical structure of starch to form a starch-lipid complex. Figure 2 It can also be seen that the treatment of the induced electric field increases the relative crystallinity of the starch lipid complex formed. Since the crystalline region is more compact than the amorphous region, it is more difficult to be hydrolyzed. This is consistent with the experimental results of in vitro digestibility, which show that the RDS content decreases, the RS starch content increases, and the digestibility decreases.

[0100] 2.5 Fourier transform infrared spectroscopy analysis of high amylose corn starch-stearic acid complex

[0101] 1047cm-1 and 1022cm-1 are typical vibration absorption peaks. The absorption peak near wave number 1047cm-1 is related to the crystalline structure of starch, and the absorption peak near 1022cm-1 is related to the amorphous structure of starch. Therefore, the ratio of the two absorption peaks can characterize the short-range ordered structure of starch. 1 The larger the absorption peak ratio at / 1022cm-1, the higher the degree of order. Figure 3 It can be seen that after the induction electric field assisted treatment, the starch lipid complex 1047cm- 1 / 1022cm-1 increases, indicating that the short-range order of the sample increases, the stability increases, and it is more difficult to digest, which is consistent with the results of X-ray diffraction measurement.

[0102] The above is an explanation of the embodiments of the present invention. By describing the disclosed embodiments, professionals in the field can implement or use the present invention, but it is not used to limit the present invention. It is impossible to fully reflect the various contents involved in the present invention in the above embodiments. Any equivalent changes or modifications made by any professional familiar with this technology without departing from the spirit or scope of the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a starch-lipid complex, characterized in that: The specific steps include: S1: Preparation of debranched starch: starch is prepared into a starch suspension, and then sterilized by high pressure to gelatinize the starch suspension, the gelatinized starch suspension is cooled, and after cooling, pullulanase is added and stirred to perform a debranching reaction, and after the reaction, the pH of the reaction system is adjusted to 7, and then the enzyme is inactivated, the temperature is lowered, and a precipitate is obtained by centrifugation, and the precipitate is washed with hot ethanol. The washed precipitate is freeze-dried, ground, and sieved to obtain debranched starch; S2: Preparation of starch lipid complex: the debranched starch obtained above is made into a homogenate, and then lipid is added and stirred. After stirring evenly, the mixture is heated, and then the reaction system is pumped into an induced electric field for treatment. After the treatment, the mixture is cooled. After cooling, the mixture is stirred and centrifuged to obtain a precipitate, which is washed with hot ethanol. The washed precipitate is freeze-dried, ground, and sieved to obtain a starch lipid complex.

2. The method according to claim 1, characterized in that The lipid in step S2 is any one or more of palmitic acid, stearic acid, and oleic acid.

3. The method according to claim 1, characterized in that The stirring time in step S1 is 10-14 hours, and the enzyme inactivation method is boiling for 15 minutes.

4. The method according to claim 1, characterized in that: The concentration of the starch suspension in step S1 is 50-100 g / L.

5. The method according to claim 1, characterized in that The pullulanase added in step S1 is 10-100u / g starch.

6. The method according to claim 1, characterized in that In step S2, the excitation voltage of the induced electric field is 150-300V, the frequency is 400-700Hz, the processing time is 1-2h, and the rotation speed of the pump is 30-50rpm.

7. The method according to claim 1, characterized in that The concentration of the homogenate in step S2 is 50-100 g / L.

8. The method according to claim 1, characterized in that The amount of lipid added in step S2 is 5-10% of the mass of the starch in step S1, and the heating temperature in step S2 is 80-90°C.

9. The starch-lipid complex prepared by the method according to any one of claims 1 to 8.

Images