Preparation method of starch-lipid compound

Abstract

The invention belongs to the technical field of functional food, and particularly relates to a preparation method of a starch-lipid compound. According to the method, starch is adopted as a raw material, under the synergistic effect of alpha-amylase, pullulanase and high-temperature pressure heat, the amylose content of the starch is increased, an important material base, namely amylose, is provided for formation of RS5, and finally the compounding rate of a starch-lipid compound is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of functional foods, and in particular relates to a method for preparing a starch-lipid complex. Background Art

[0002] Resistant starch (RS) is a carbohydrate that can significantly lower blood sugar and maintain the body's blood sugar homeostasis. Eating resistant starch in your daily diet can prevent and regulate diabetes, while also improving intestinal and colon health, regulating fat metabolism and controlling body weight.

[0003] Starch-lipid complexes are the fifth type of resistant starch, formed when starch is heated and cooled and lipids (such as fatty acids, monoglycerides and lysophospholipids) are embedded in the helical hydrophobic cavity of starch molecules. The resulting complex is called RSV type (i.e. RS5) and is gaining more and more attention from researchers.

[0004] However, the main method for preparing RS5 currently is to use common wheat or corn starch as raw material, debranch the starch for a long time at low temperature, and then complex the debranched starch with lipids in a constant temperature system. The entire preparation process takes a long time, usually 2d-7d. The preparation of starch-lipid complex (RS5) has problems such as complex process, long complex time, and poor complex effect. Therefore, improving the current process to shorten the preparation time of RS5 is of great significance to the industrial production of RS5. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a method for preparing a starch-lipid complex, which can significantly improve the RS5 complexation rate.

[0006] The technical solution adopted by the present invention is:

[0007] A method for preparing a starch-lipid complex comprises the following steps:

[0008] 1) Mix starch with sodium acetate diluent and swell in a water bath shaker to obtain starch paste;

[0009] 2) adding α-amylase to the starch paste, then heating and keeping warm and then cooling;

[0010] 3) adding pullulanase to the starch paste treated in step 2) for enzymolysis;

[0011] 4) adding lipid to the enzymatically hydrolyzed starch paste, stirring and heating to carry out a composite reaction;

[0012] 5) After the complex reaction is completed, centrifuge and discard the supernatant. Wash the precipitate and centrifuge again. The precipitate is freeze-dried to obtain the starch-lipid complex.

[0013] In the step 1), the mass ratio of starch to sodium acetate diluent is 1:10-12; the sodium acetate diluent is 3M sodium acetate buffer diluted 150 times, and the pH is 5.2.

[0014] In the step 1), the water bath temperature is 55-60° C., the shaking speed is 180-200 rpm, and the swelling time is 12-16 hours.

[0015] In the step 2), the amount of α-amylase added is 0.1U-1.0U / g starch, and the heating and heat preservation conditions are to heat to 128-130°C for 20-30min, keep the temperature for 40-45min, and then cool to 55-60°C.

[0016] In the step 3), the amount of pullulanase added is 60-80 U / g starch, and the enzymatic hydrolysis is carried out at 55-60° C. for 6-8 hours.

[0017] In the step 4), the amount of lipid added is 1 / 30-1 / 15 of the mass of starch, the temperature is raised to 70-80° C. during the composite reaction, the composite reaction is carried out for 2-3 hours, and the stirring speed is 150-200 rpm.

[0018] The centrifugation condition in step 5) is centrifugation at 3000 rpm for 10 min.

[0019] The starch includes one or more of common corn starch, wheat starch and potato starch.

[0020] The lipids include one or more of lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid or glycerides.

[0021] Compared with the prior art, the beneficial technical effects of the present invention are:

[0022] 1. Low straight chain content and long debranching time in common wheat and corn starch are the main reasons for the low composite rate of RS5, which limits the development of RS5 continuous preparation industry. Therefore, the present invention introduces α-amylase-resistant and debranching enzyme pullulanase, and utilizes the synergistic effect of thermostable α-amylase, debranching enzyme pullulanase and high temperature autoclave to increase the straight chain content of starch, providing an important material basis for the formation of RS5-amylose.

[0023] 2. Based on the production of amylose, the present invention enables the prepared starch-lipid complex to have a composite rate of more than 43.2%. Compared with the original corn starch, the in vitro digestion test shows that the hydrolysis rate of the prepared starch-lipid complex is significantly reduced, showing good anti-digestion performance.

[0024] 3. The starch-lipid complex prepared by the present invention can be used as a raw material for food, functional food and health food. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The XRD diagram of the product of the embodiment.

[0026] Figure 2 It is the electron microscope scanning image of the product of embodiment.

[0027] Figure 3 The DSC thermal scanning diagram of the product of the embodiment.

[0028] Figure 4 The thermogravimetric curve of the product of Example 1 is shown in FIG.

[0029] Figure 5 It is the differential thermogravimetric curve of the product of Example.

[0030] Figure 6 The following is the Fourier infrared spectrum of the product of the embodiment. DETAILED DESCRIPTION

[0031] The specific implementation modes of the present invention are described below in conjunction with examples. However, the following examples are only used to illustrate the present invention in detail and are not intended to limit the scope of the present invention in any way.

[0032] Embodiment 1:

[0033] A method for preparing a starch-lipid complex comprises the following steps:

[0034] 1) Weigh 30 g corn starch into a 500 mL conical flask, add 300 mL of sodium acetate diluent (3 M sodium acetate buffer diluted 150 times) with a pH of 5.2, and place in a 55°C water bath shaker to swell for 12 h to obtain starch paste. The shaker speed is 190 rpm.

[0035] 2) After swelling, the starch paste was reacted in a high pressure steam sterilizer (0.12-0.15 MPa) at 128°C for 40 min. After the reaction, it was immediately placed in a 55°C water bath shaker for 20 min to cool down. The shaking speed was 170 rpm.

[0036] 3) Add pullulanase (addition amount is 60U / g starch) into the conical flask and perform enzymolysis at 55°C for 6h.

[0037] 4) After the enzymatic hydrolysis, 1.2 g of lauric acid was added to the conical flask, and the reaction was carried out in a 75° C. water bath for 2.5 h. During the reaction, a rotor was added to keep the solution in a stirring state at a stirring speed of 180 rpm.

[0038] 5) After the complex reaction is completed, the sample is centrifuged at 3000 rpm for 10 min in a centrifuge, the upper aqueous phase is discarded, the solid phase is washed 5 times with anhydrous ethanol, and centrifuged again at 3000 rpm for 10 min. The solid phase is freeze-dried to obtain 27.2 g of starch-lipid complex.

[0039] Embodiment 2:

[0040] A method for preparing a starch-lipid complex comprises the following steps:

[0041] 1) Weigh 30 g corn starch into a 500 mL conical flask, add 300 mL of sodium acetate diluent (3 M sodium acetate buffer diluted 150 times) with a pH of 5.2, and place in a 55°C water bath shaker to swell for 12 h to obtain starch paste. The shaker speed is 190 rpm.

[0042] 2) After swelling, α-amylase (0.1 U / g starch) was added to the starch paste, and the mixture was reacted in a high pressure steam sterilizer (0.12-0.15 MPa) at 128° C. for 40 min. After the reaction, the mixture was immediately placed in a 55° C. water bath shaker for 20 min to cool down, and the shaker speed was 170 rpm.

[0043] 3) Add pullulanase (addition amount is 60U / g starch) into the conical flask and perform enzymolysis at 55°C for 6h.

[0044] 4) After the enzymatic hydrolysis, 1.2 g of lauric acid was added to the conical flask, and the reaction was carried out in a 75° C. water bath for 2.5 h. During the reaction, a rotor was added to keep the solution in a stirring state at a stirring speed of 180 rpm.

[0045] 5) After the complex reaction is completed, the sample is centrifuged at 3000 rpm for 10 min in a centrifuge, the upper aqueous phase is discarded, the solid phase is washed 5 times with anhydrous ethanol, and centrifuged again at 3000 rpm for 10 min. The solid phase is freeze-dried to obtain 29.6 g of starch-lipid complex.

[0046] Embodiment 3:

[0047] A method for preparing a starch-lipid complex comprises the following steps:

[0048] 1) Weigh 30 g corn starch into a 500 mL conical flask, add 300 mL of sodium acetate diluent (3 M sodium acetate buffer diluted 150 times) with a pH of 5.2, and place in a 55°C water bath shaker to swell for 12 h to obtain starch paste. The shaker speed is 190 rpm.

[0049] 2) After swelling, α-amylase (0.25 U / g starch) was added to the starch paste, and the mixture was reacted at 128° C. for 40 min in a high pressure steam sterilizer (0.12-0.15 MPa). After the reaction, the mixture was immediately placed in a 55° C. water bath shaker for 20 min to cool down, and the shaker speed was 170 rpm.

[0050] 3) Add pullulanase (addition amount is 60U / g starch) into the conical flask and perform enzymolysis at 55°C for 6h.

[0051] 4) After the enzymatic hydrolysis, 1.2 g of lauric acid was added to the conical flask, and the reaction was carried out in a 75° C. water bath for 2.5 h. During the reaction, a rotor was added to keep the solution in a stirring state at a stirring speed of 180 rpm.

[0052] 5) After the complex reaction is completed, the sample is centrifuged at 3000 rpm for 10 min in a centrifuge, the upper aqueous phase is discarded, the solid phase is washed 5 times with anhydrous ethanol, and centrifuged again at 3000 rpm for 10 min. The solid phase is freeze-dried to obtain 29.5 g of starch-lipid complex.

[0053] Embodiment 4:

[0054] A method for preparing a starch-lipid complex comprises the following steps:

[0055] 1) Weigh 30 g corn starch into a 500 mL conical flask, add 300 mL of sodium acetate diluent (3 M sodium acetate buffer diluted 150 times) with a pH of 5.2, and place in a 55°C water bath shaker to swell for 12 h to obtain starch paste. The shaker speed is 190 rpm.

[0056] 2) After swelling, α-amylase (0.5 U / g starch) was added to the starch paste, and the mixture was reacted at 128° C. for 40 min in a high pressure steam sterilizer (0.12-0.15 MPa). After the reaction, the mixture was immediately placed in a 55° C. water bath shaker for 20 min to cool down, and the shaker speed was 170 rpm.

[0057] 3) Add pullulanase (addition amount is 60U / g starch) into the conical flask and perform enzymolysis at 55°C for 6h.

[0058] 4) After the enzymatic hydrolysis, 1.2 g of lauric acid was added to the conical flask, and the reaction was carried out in a 75° C. water bath for 2.5 h. During the reaction, a rotor was added to keep the solution in a stirring state at a stirring speed of 180 rpm.

[0059] 5) After the complex reaction is completed, the sample is centrifuged at 3000 rpm for 10 min in a centrifuge, the upper aqueous phase is discarded, the solid phase is washed 5 times with anhydrous ethanol, and centrifuged again at 3000 rpm for 10 min. The solid phase is freeze-dried to obtain 30.3 g of starch-lipid complex.

[0060] Embodiment 5:

[0061] A method for preparing a starch-lipid complex comprises the following steps:

[0062] 1) Weigh 30 g corn starch into a 500 mL conical flask, add 300 mL of sodium acetate diluent (3 M sodium acetate buffer diluted 150 times) with a pH of 5.2, and place in a 55°C water bath shaker to swell for 12 h to obtain starch paste. The shaker speed is 190 rpm.

[0063] 2) After swelling, add α-amylase (addition amount is 1.0U / g starch), react in a high pressure steam sterilizer (0.12-0.15MPa) at 128°C for 40min, and immediately put into a 55°C water bath shaker for 20min to cool down after the reaction, with the shaker speed at 170rpm.

[0064] 3) Add pullulanase (addition amount is 80U / g starch) into the conical flask and perform enzymolysis at 55°C for 6h.

[0065] 4) After the enzymatic hydrolysis, 1.2 g of lauric acid was added to each conical flask, and the reaction was carried out in a 75° C. water bath for 2.5 h. During the reaction, a rotor was added to keep the solution in a stirring state at a stirring speed of 180 rpm.

[0066] 5) After the complex reaction is completed, the sample is centrifuged at 3000 rpm for 10 min in a centrifuge, the upper aqueous phase is discarded, the solid phase is washed 5 times with anhydrous ethanol, and centrifuged again at 3000 rpm for 10 min. The solid phase is freeze-dried to obtain 31.2 g of starch-lipid complex.

[0067] Example 6

[0068] A method for preparing a starch-lipid complex comprises the following steps:

[0069] 1) Weigh 30 g corn starch into a 500 mL conical flask, add 300 mL of sodium acetate diluent (3 M sodium acetate buffer diluted 150 times) with a pH of 5.2, and place in a 55°C water bath shaker to swell for 12 h to obtain starch paste. The shaker speed is 190 rpm.

[0070] 2) After swelling, add α-amylase (addition amount is 1.0U / g starch), react in a high pressure steam sterilizer (0.12-0.15MPa) at 128°C for 40min, and immediately put into a 55°C water bath shaker for 20min to cool down after the reaction, with the shaker speed at 170rpm.

[0071] 3) 1.2 g of lauric acid was added to each conical flask, and the mixture was reacted in a 75° C. water bath for 2.5 h. During the reaction, a rotor was added to keep the solution in a stirring state at a stirring speed of 180 rpm.

[0072] 4) After the complex reaction is completed, the sample is centrifuged at 3000 rpm for 10 min in a centrifuge, the upper aqueous phase is discarded, the solid phase is washed 5 times with anhydrous ethanol, and centrifuged again at 3000 rpm for 10 min. The solid phase is freeze-dried to obtain 27.4 g of starch-lipid complex.

[0073] Example 7

[0074] A method for preparing a starch-lipid complex comprises the following steps:

[0075] 1) Weigh 30 g corn starch into a 500 mL conical flask, add 300 mL of sodium acetate diluent (3 M sodium acetate buffer diluted 150 times) with a pH of 5.2, and place in a 55°C water bath shaker to swell for 12 h to obtain starch paste. The shaker speed is 190 rpm.

[0076] 2) After swelling, add α-amylase (addition amount is 1.0 U / g starch) and cool in a 55° C. water bath shaker for 20 min at a shaking speed of 170 rpm.

[0077] 3) Add pullulanase (addition amount is 60U / g starch) into the conical flask and perform enzymolysis at 55°C for 6h.

[0078] 4) After the enzymatic hydrolysis, 1.2 g of lauric acid was added to each conical flask, and the reaction was carried out in a 75° C. water bath for 2.5 h. During the reaction, a rotor was added to keep the solution in a stirring state at a stirring speed of 180 rpm.

[0079] 5) After the complex reaction is completed, the sample is centrifuged at 3000 rpm for 10 min in a centrifuge, the upper aqueous phase is discarded, the solid phase is washed 5 times with anhydrous ethanol, and centrifuged again at 3000 rpm for 10 min. The solid phase is freeze-dried to obtain 28.6 g of starch-lipid complex.

[0080] Effect experiment:

[0081] 1. Determination of recombination rate and hydrolysis rate:

[0082] Determination of the composite rate: Take 2g potassium iodide and 1.3g iodine, dilute to 100mL with distilled water, heat and dissolve to obtain iodine solution; take 100mg sample in a 50mL centrifuge tube, add 4.9mL distilled water, boil in a boiling water bath for 1h, take it out after the end, cool to room temperature, add 10mL distilled water, vortex for 2min, centrifuge at 4000rpm for 10min in a centrifuge, take 500uL of the supernatant in a conical flask after the end, add 15mL distilled water and 2mL iodine solution, shake well, draw 250uL of the sample solution into the ELISA plate, use an ELISA reader to measure its absorbance at 620nm, and use the original corn starch as the blank control. Repeat the test for three samples.

[0083] Recombination rate CI (%) = (A 0 -A) / A 0 ×100%.

[0084] A 0 is the absorbance of native corn starch, and A is the absorbance of the sample.

[0085] 2. Determination of hydrolysis rate:

[0086] The sample (500 mg) was dispersed in 10 ml of sodium acetate buffer solution (0.2 M, pH 5.2) and boiled in a boiling water bath for 30 minutes. The cooked sample was then kept at 37°C for 10 minutes and mixed with 5 ml of enzyme solution (pancreatin and α-glucosidase). The enzyme solution was prepared as follows: 3 g of pancreatin was suspended in 20 ml of water, centrifuged at 3000 g for 10 minutes, and then 15 ml of supernatant was collected and mixed with 1.1 ml of α-glucosidase. The reaction mixture was stirred at 160 rpm in a 37°C water bath. At 120 minutes, 500 microliters of the hydrolyzate were taken out and added to 5 ml of anhydrous ethanol. The amount of glucose released was measured using a glucose oxidase-peroxidase kit (Beijing Leadman Biochemical Co., Ltd., Beijing, China). The three sample tests were repeated.

[0087] Hydrolysis rate (%) = G × 0.9 / TS × 100%

[0088] Where G is the measured amount of glucose and TS represents the total mass of starch.

[0089] The results of the compounding rate and hydrolysis rate of Examples 1-7 are shown in the following table:

[0090] Grouping Compound Rate Hydrolysis rate (%) Example 1 25.52±0.20％ 68.69±1.28 Example 2 27.61±0.72％ 66.77±0.94 Example 3 30.76±1.51％ 67.75±0.92 Example 4 36.89±1.33％ 54.19±1.16 Example 5 42.35±0.72％ 41.04±0.31 Example 6 21.13±0.52％ 70.39±0.43 Example 7 20.78±0.51％ 71.84±0.29 Native corn starch 0 75.84±0.77

[0091] As can be seen from the above table, the hydrolysis rate of the starch-lipid complex prepared in each embodiment is significantly lower than that of the original corn starch, among which the starch-lipid complex prepared in Example 5 has the highest complexation rate of 42.35±0.72% and the lowest hydrolysis rate of 41.04±0.31%, indicating that the starch and lipid complex have good resistance to amylase hydrolysis.

[0092] The starch-lipid complex and native corn starch obtained in Examples 1-5 were subjected to XRD and electron microscopy tests, and the results were as follows: Figure 1 and Figure 2 The starch-lipid complex and native corn starch obtained in Examples 1-5 were analyzed using a thermal scanner, and the results are shown in Figure 3The starch-lipid complex and native corn starch obtained in Examples 1-5 were analyzed using a thermogravimetric analyzer, and the obtained thermogravimetric curves and differential thermogravimetric curves were shown as follows: Figure 4 , Figure 5 The starch-lipid complex and the original corn starch obtained in Example 1-5 were analyzed by Fourier transform infrared spectrometer, and the Fourier transform infrared spectra were obtained as shown in FIG. Figure 6 shown.

[0093] AE correspond to the starch-lipid complexes obtained in Examples 1-5, respectively, and F is corn starch without any treatment as a control.

[0094] Depend on Figure 1 It can be seen that Figure 1 The X-ray diffraction patterns of the untreated raw corn starch and RS5 of Examples 1-5 are shown. The raw corn starch A shows a typical A-type crystal form at 15°, 17°, 18° and 23° (2θ), and the other samples (B, C, D, E) have obvious peaks at 8°, 13.4° and 20° (2θ), which are characteristic peaks of a typical V-type crystal structure, indicating that a starch-lipid complex is formed, while sample E has a peak shift at 20° (2θ) and an obvious peak at 21° (2θ), which is a characteristic peak of a B-type crystal structure, indicating that sample E has both V-type and B-type crystal forms, and this structure is conducive to the fatty acid entering the starch cavity and forming a package, which can increase the starch-lipid compound rate, which is consistent with the result of the compound rate.

[0095] Depend on Figure 2 It can be seen that the scanning electron microscope images of the 10000× and 1000× samples are as follows Figure 2 As shown. The F particles are polyhedral or elliptical, have good dispersibility, and have a relatively smooth surface (Figure F). It can be observed that the AD samples aggregated into a larger form with a small specific surface area, and the E samples were enzymatically hydrolyzed into a dispersed smaller form with a large specific surface area. The debranched corn starch with a large specific surface area can increase the contact area with fatty acids, which is more conducive to the recombination of fatty acids. Therefore, the recombination rate of E is higher, which is consistent with the result of the recombination rate.

[0096] Depend on Figure 3It can be seen that compared with ordinary corn starch (F), starch lipid complex (AE) has a second peak in the range of 270-300°C, indicating that starch lipid complex (AE) has better thermal stability than ordinary corn starch (F). The reason is: ordinary corn starch has poor thermal stability, so it will decompose at a low temperature and produce enthalpy change, which is reflected in the large enthalpy change value of ordinary corn starch, while starch lipid complex (AE) has good thermal stability, so it will not completely decompose at a low temperature, which is reflected in the low enthalpy change value produced by starch lipid complex (AE), and will continue to be thermally decomposed at a higher temperature to produce enthalpy change (second peak).

[0097] At the same time by Figure 3 It can be seen that the starch lipid complex (AE) will continue to decompose when heated above 270°C, and in daily life applications, it is almost difficult to reach 270°C, which proves the practicality of the starch lipid complex (AE) prepared by the present invention. At the same time, compared with other starch lipid complexes (AD), the starch lipid complex E has the smallest enthalpy change value during the second decomposition, which is only 32 J / g, which is 48 J / g lower than the sample with the largest enthalpy change value, proving that the thermal stability of the starch lipid complex E (Example 5) is better.

[0098] Depend on Figure 4 It can be seen from the thermogravimetric curve that the mass loss of starch lipid complex (AE) mainly occurs in three stages. The first stage is in the range of 0-100℃, which is mainly caused by the evaporation of water in the sample; the second stage is in the range of 120-220℃, mainly due to the degradation of fatty acid molecules in the sample. And from the thermogravimetric curve, it can be seen that the mass loss of starch lipid complex (AE) in the second stage is significantly lower than that of ordinary corn starch (F), which proves that starch lipid complex (AE) has higher thermal stability. The possible reasons are: fatty acids have lower hydrophobicity and higher dispersibility. Fatty acids are mainly dispersed in the complex, so the starch chain has a stronger protective effect on them, which improves the thermal stability of the sample. The heat loss in the third stage occurs in the range of 230-400℃, which is mainly caused by the degradation of the remaining fatty acids and uncomplexed starch in the starch lipid complex (AE).

[0099] Depend on Figure 5It can be seen from the differential thermogravimetric curve that the temperature corresponding to the maximum mass loss rate of the starch lipid complex (E) at this stage is generally the highest, indicating that the starch lipid complex (E) has the best thermal stability. The inventors speculate that this may be due to the tight and orderly arrangement of the V-type straight-chain starch single helices in the complex, which improves the thermal stability of the starch chain and can resist the hydrolysis of the starch chain in the complex by digestive enzymes to a certain extent, thereby improving the thermal stability of the sample. This is consistent with the results of XRD. It is also found through the thermogravimetric curve that the temperature corresponding to the maximum mass loss rate of the starch lipid complex (E) in the third stage is the highest, indicating that it has the best thermal stability. The starch lipid complex (E) has the best thermal stability, which is consistent with the results of DSC.

[0100] Depend on Figure 6 It can be seen that the FTIR spectrum of the sample is Figure 6 As shown. 3400cm -1 The absorption band is caused by the stretching vibration of the hydroxyl group. Compared with the spectrum of ordinary corn starch (F), the characteristic peak of the hydroxyl group of the starch lipid complex (AE) moves to a higher wave number, indicating that the interaction between the hydroxyl groups of corn starch and fatty acids is enhanced, proving the complexation of starch and fatty acids.

[0101] It was also found that the starch lipid complex of the present invention had a -1 and 2900.0cm -1 Two absorption peaks are found near the carbonyl group and the methylene group in the fatty acid molecule. These two peaks are caused by the stretching vibration of the carbonyl group and the methylene group in the fatty acid molecule. Since the complex can reduce the absorption of these two peaks on the infrared spectrum to a certain extent, the smaller the peak, the better the composite effect. Figure 6 It can be seen that compared with other starch-lipid complexes, starch-lipid complex (E) has the best complexing effect, which is consistent with the results of complexing rate and XRD.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing a starch-lipid complex, characterized in that: The following steps are involved: 1) Mix starch with sodium acetate diluent and swell in a water bath shaker to obtain starch paste; 2) adding α-amylase to the starch paste, then heating and keeping warm and then cooling; 3) adding pullulanase to the starch paste treated in step 2) for enzymolysis; 4) adding lipid to the enzymatically hydrolyzed starch paste, stirring and heating to carry out a composite reaction; 5) After the complex reaction is completed, centrifuge twice and freeze-dry the precipitate to obtain the starch-lipid complex.

2. The preparation method according to claim 1, characterized in that: In the step 1), the mass ratio of starch to sodium acetate diluent is 1:10-12.

3. The preparation method according to claim 1, characterized in that: In the step 1), the water bath temperature is 55-60° C., the shaking speed is 180-200 rpm, and the swelling time is 12-16 hours.

4. The preparation method according to claim 1, characterized in that: In the step 2), the amount of α-amylase added is 0.1U-1.0U / g starch, and the heating and heat preservation conditions are to heat to 128-130°C for 20-30min, keep the temperature for 40-45min, and then cool to 55-60°C.

5. The preparation method according to claim 1, characterized in that: In the step 3), the amount of pullulanase added is 60-80 U / g starch, and the enzymatic hydrolysis is carried out at 55-60° C. for 6-8 hours.

6. The preparation method according to claim 1, characterized in that: In the step 4), the amount of lipid added is 1 / 30-1 / 15 of the mass of starch, the temperature is raised to 70-80° C. during the composite reaction, the composite reaction is carried out for 2-3 hours, and the stirring speed is 150-200 rpm.

7. The preparation method according to claim 1, characterized in that: The centrifugation condition in step 5) is centrifugation at 3000 rpm for 10 min.

8. The preparation method according to claim 1, characterized in that: The starch includes one or more of common corn starch, wheat starch and potato starch.

9. The preparation method according to claim 1, characterized in that: The lipids include one or more of lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid or glycerides.

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