1. A preparation method of a macromolecular starch-based emulsifier is characterized by comprising the following steps:

preparing starch into a starch aqueous solution with the mass concentration of 30-40% by using water; carrying out acidolysis, enzymolysis or oxidation treatment on the starch aqueous solution to obtain a pretreated starch aqueous solution;

adjusting the pH value of the pretreated starch water solution to 6-11, adding octenyl succinic anhydride, and performing esterification reaction to obtain esterification reaction feed liquid;

washing the esterification reaction liquid in sequence, and then carrying out spray drying or roller drying to obtain the macromolecular starch-based emulsifier;

the mass of the octenyl succinic anhydride is 1.0-15% of that of the starch.

2. The preparation method according to claim 1, wherein the esterification reaction is carried out at a temperature of 20 to 70 ℃ for 1 to 20 hours.

3. The method as claimed in claim 1, wherein the agent for acid hydrolysis comprises an inorganic acid or an organic acid; the inorganic acid comprises hydrochloric acid, phosphoric acid or sulfuric acid; the organic acid comprises citric acid; the mass of the acidolysis reagent is 0.5-5% of the mass of starch.

4. The preparation method according to claim 3, wherein the mass concentration of the hydrochloric acid is 30-35%; the mass concentration of the phosphoric acid is more than or equal to 85 percent, and the mass concentration of the sulfuric acid is more than or equal to 98.0 percent; the mass content of the citric acid is more than or equal to 99.0%.

5. The preparation method according to claim 1, wherein the agent for oxidation treatment comprises sodium hypochlorite or hydrogen peroxide; the mass of the reagent for oxidation treatment is 20-30% of the mass of starch.

6. The preparation method of claim 5, wherein the effective chlorine concentration of the sodium hypochlorite is more than or equal to 10.0%, and the mass concentration of the hydrogen peroxide is more than or equal to 27.5%.

7. The method according to claim 1, wherein the enzyme for enzymatic treatment comprises β -amylase, pullulanase, maltase, pullulanase, exo-alpha-1, 4-glucosidase or exo-1, 4-alpha-D-glucanase; the mass of the enzyme subjected to enzymolysis treatment is 0.02-1.0% of the mass of starch.

8. The macromolecular starch-based emulsifier obtained by the preparation method according to any one of claims 1 to 7, wherein the viscosity of the macromolecular starch-based emulsifier is 600 to 3000 mPa-s, and the mass content of octenyl succinic acid groups is 2.5 to 3.5%; taking salad oil as an example, 1g of emulsifier emulsifies 8-40 g of salad oil.

9. Use of a macromolecular starch-based emulsifier according to claim 8 for the preparation of an emulsion.

10. Use according to claim 9, wherein the emulsifier is a macromolecular starch-based emulsifier, or a mixture of a macromolecular starch-based emulsifier and a low viscosity starch octenyl succinate when preparing the emulsion; the macromolecular starch-based emulsifier of claim 8.

Background

Octenyl succinic starch ester abbreviated as OSA starch, which is a pure gum and is an emulsion thickener with high safety, was patented by Caldwell and Wurzburg in 1953, and was included in the US food additive category in 1972. Scientists in the united states, europe, japan, etc. have improved the preparation and application techniques of the product over the years. In foreign countries, the product has already entered into industrial mass production. The national starch, the Jiaji starch, the French Rogat and the like all come out of series products. In China, the research on the product starts from 2000, products in the current market are mainly imported, the products are mainly enzymolysis or dextrinization low-viscosity products, and the products have certain emulsification stability and can replace Arabic gum in the aspect of microcapsule embedding; however, these products generally have a problem that the molecular weight is too small to emulsify high-fold oil components with a low addition amount, and the products are difficult to function in a dilute oil-water emulsion system, and are difficult to achieve good emulsification stability and entrapment for some longer-chain oils. Against this background, it has become a hot research to provide a high-efficiency emulsifier which has both emulsification and thickening effects.

Disclosure of Invention

In view of the above, the present invention aims to provide a macromolecular starch-based emulsifier, and a preparation method and an application thereof.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a preparation method of a macromolecular starch-based emulsifier, which comprises the following steps:

preparing starch into a starch aqueous solution with the mass concentration of 30-40% by using water; carrying out acidolysis, enzymolysis or oxidation treatment on the starch aqueous solution to obtain a pretreated starch aqueous solution;

adjusting the pH value of the pretreated starch water solution to 6-11, adding octenyl succinic anhydride, and performing esterification reaction to obtain esterification reaction feed liquid;

washing the esterification reaction liquid in sequence, and then carrying out spray drying or roller drying to obtain the macromolecular starch-based emulsifier;

the mass of the octenyl succinic anhydride is 1.0-15% of that of the starch.

Preferably, the temperature of the esterification reaction is 20-70 ℃ and the time is 1-20 h.

Preferably, the agent for acid hydrolysis comprises an inorganic acid or an organic acid; the inorganic acid comprises hydrochloric acid, phosphoric acid or sulfuric acid; the organic acid comprises citric acid; the mass of the acidolysis reagent is 0.5-5% of the mass of starch.

Preferably, the mass concentration of the hydrochloric acid is 30-35%; the mass concentration of the phosphoric acid is more than or equal to 85 percent, and the mass concentration of the sulfuric acid is more than or equal to 98.0 percent; the mass content of the citric acid is more than or equal to 99.0%.

Preferably, the reagent for oxidation treatment comprises sodium hypochlorite or hydrogen peroxide; the mass of the reagent for oxidation treatment is 20-30% of the mass of starch.

Preferably, the effective chlorine concentration of the sodium hypochlorite is more than or equal to 10.0%, and the mass concentration of the hydrogen peroxide is more than or equal to 27.5%.

Preferably, the enzyme for enzymatic treatment comprises beta-amylase, pullulanase, maltase, pullulanase, exo-alpha-1, 4-glucosidase or exo-1, 4-alpha-D-glucanase; the mass of the enzyme subjected to enzymolysis treatment is 0.02-1.0% of the mass of starch.

The invention also provides the macromolecular starch-based emulsifier obtained by the preparation method in the technical scheme, wherein the viscosity of the macromolecular starch-based emulsifier is 600-3000 mPa & s, and the mass content of octenyl succinic acid groups is 2.5-3.5%; taking salad oil as an example, 1g of emulsifier emulsifies 8-40 g of salad oil.

The invention also provides the application of the macromolecular starch-based emulsifier in the technical scheme in the preparation of emulsion.

Preferably, the emulsifier is a macromolecular starch-based emulsifier, or a mixture of a macromolecular starch-based emulsifier and a low viscosity octenyl succinic starch when preparing the emulsion; the macromolecular starch-based emulsifier is the macromolecular starch-based emulsifier in the technical scheme.

The invention provides a preparation method of a macromolecular starch-based emulsifier, which comprises the following steps: preparing starch into a starch aqueous solution with the mass concentration of 30-40% by using water; carrying out acidolysis, enzymolysis or oxidation treatment on the starch aqueous solution to obtain a pretreated starch aqueous solution; adjusting the pH value of the pretreated starch water solution to 6-11, adding octenyl succinic anhydride, and performing esterification reaction to obtain esterification reaction feed liquid; washing the esterification reaction liquid in sequence, and then carrying out spray drying or roller drying to obtain the macromolecular starch-based emulsifier; the mass of the octenyl succinic anhydride is 1.0-15% of that of the starch. After the pH value of a pretreated starch aqueous solution is adjusted to 6.0-11, an octenyl succinic acid derivative and a hydroxyl functional group in starch are subjected to esterification reaction; meanwhile, the quality of the octenyl succinic acid derivative is controlled to be 1.0-15% of the quality of the starch, so that the degradation of the octenyl succinic acid derivative on long-chain molecules in the starch can be guaranteed, the long-chain molecules can not be excessively degraded, and the final emulsifier has proper consistency and excellent emulsibility.

Furthermore, the invention adopts the acidolysis treatment or oxidation treatment mode, only the long chain of the starch molecule is cut off moderately in an uncertain way, the generation of small molecular sugar is avoided, the molecular weight of the obtained degraded starch is larger, and the lipophilicity and the emulsifying property can be kept better; beta-amylase, pullulanase, maltase, pullulanase, exo-alpha-1, 4-glucase or exo-1, 4-alpha-D-glucanase are selected for enzymolysis, and starch is incompletely degraded to obtain limit dextrin and polysaccharide with larger molecular weight, so that the water solubility of the obtained emulsifier is increased, and simultaneously, better emulsibility can be kept.

The data of the examples show that: the viscosity of the macromolecular starch-based emulsifier prepared by the invention is 600-3000 mPa & s, and the mass content of octenyl succinic acid group is 2.5-3.5%; taking salad oil as an example, 1g of emulsifier emulsifies 8-40 g of salad oil.

Detailed Description

The invention provides a preparation method of a macromolecular starch-based emulsifier, which comprises the following steps:

preparing starch into a starch aqueous solution with the mass concentration of 30-40% by using water; carrying out acidolysis, enzymolysis or oxidation treatment on the starch aqueous solution to obtain a pretreated starch aqueous solution;

adjusting the pH value of the pretreated starch water solution to 6-11, adding octenyl succinic anhydride, and performing esterification reaction to obtain esterification reaction feed liquid;

and washing the esterification reaction liquid in sequence, and then carrying out spray drying or roller drying to obtain the macromolecular starch-based emulsifier.

The method comprises the steps of preparing starch into a starch aqueous solution with the mass concentration of 30-40% by using water; and carrying out acidolysis, enzymolysis or oxidation treatment on the starch aqueous solution to obtain a pretreated starch aqueous solution.

In the present invention, the starch is preferably a native starch; the specific source of the natural starch is not specifically limited, and the natural starch can be extracted from any natural source; in a particular embodiment of the invention, the native starch is preferably tapioca starch or waxy maize starch.

In the present invention, the water in the aqueous starch solution is preferably deionized water.

In the present invention, the acidolysis reagent preferably includes an inorganic acid or an organic acid, and the mass of the acidolysis reagent is preferably 0.5 to 5% of the mass of starch, and more preferably 2 to 3%. In the present invention, the inorganic acid preferably includes hydrochloric acid, phosphoric acid or sulfuric acid; the mass concentration of the hydrochloric acid is preferably 30-35%, and more preferably 32%; the mass concentration of the phosphoric acid is preferably equal to or more than 85%, the mass concentration of the sulfuric acid is preferably equal to or more than 98.0%, and in the invention, the organic acid preferably comprises citric acid, and the mass content of the citric acid is preferably equal to or more than 99.0%. In the invention, the acidolysis treatment temperature is preferably 40-60 ℃; the acidolysis treatment time is preferably 5-20 h. In the present invention, the acid hydrolysis treatment makes it possible to shorten the long chains of the starch and even to produce partial dextrins.

In the invention, the reagent for oxidation treatment preferably comprises sodium hypochlorite or hydrogen peroxide, and the mass of the reagent for oxidation treatment is preferably 20-30% of that of starch. In the present invention, the effective chlorine concentration of the sodium hypochlorite is preferably not less than 10.0%. In the invention, the mass concentration of the hydrogen peroxide is preferably more than or equal to 27.5%. In the invention, the temperature of the oxidation treatment is preferably 25-40 ℃, and the time is preferably 4-10 h. In the present invention, the oxidation treatment oxidizes starch, and the long chain is appropriately cut and shortened while the hydroxyl functional group is changed to a carboxyl group.

In the present invention, the enzyme for the enzymatic treatment preferably includes β -amylase, pullulanase, maltase, pullulanase, exo-alpha-1, 4-glucosidase or exo-1, 4-alpha-D-glucanase; the mass of the enzyme is preferably 0.02-1.0% of the mass of starch. In the invention, the temperature of the enzymolysis treatment is preferably 30-90 ℃, and the time is preferably 0.5-20 h. After the enzymatic treatment, the invention preferably further comprises: and adjusting the pH value of the obtained enzymolysis treatment liquid to 4.0-4.5 so as to achieve the effect of enzyme deactivation. In the invention, the enzymolysis treatment can lead the starch to be incompletely converted into sugar and partial limit dextrin.

After the pretreated starch aqueous solution is obtained, the pH value of the pretreated starch aqueous solution is adjusted to 6-11, and then octenyl succinic anhydride is added for esterification reaction to obtain esterification reaction feed liquid.

In the invention, the pH value is preferably 7.0-9.0; the pH value adjusting reagent is preferably an alkali solution; the concentration and the dosage of the alkali solution are not particularly limited, as long as the pH value of the pretreated starch water solution is 6.0-11.0.

In the present invention, the mass of the octenyl succinic anhydride is 1.0 to 15%, and more preferably 1.0 to 7.0% of the mass of the starch. In the present invention, the octenyl succinic anhydride is preferably used in the form of an aqueous solution of octenyl succinic anhydride, and the addition rate of the aqueous solution of octenyl succinic anhydride is preferably 1 g/min.

In the invention, the temperature of the esterification reaction is preferably 20-90 ℃, more preferably 25-40 ℃, and the time is preferably 1-20 hours, more preferably 3-12 hours.

After the esterification reaction, the method preferably further comprises the step of adjusting the pH value of the obtained esterification reaction feed liquid to 4.5-6.5; the reagent for adjusting the pH value of the obtained esterification reaction liquid is preferably hydrochloric acid, and the concentration and the dosage of the hydrochloric acid are not particularly limited as long as the pH value of the obtained esterification reaction liquid can be adjusted to 4.5-6.5.

After the esterification reaction feed liquid is obtained, the esterification reaction feed liquid is sequentially washed and then spray-dried or roller-dried to obtain the macromolecular starch-based emulsifier.

In the present invention, the washing reagent is preferably deionized water; the washing is preferably in a cyclone scrubberIs carried out in (1). The washing process parameters are not particularly limited, as long as the conductivity of the washed esterification reaction feed liquid is less than or equal to 500 mus/cm²And (4) finishing.

In the invention, the steam pressure of the roller drying is preferably 0.4-0.70 MPa, and the temperature is preferably 130-155 ℃; the air inlet temperature of the spray drying is preferably 150-240 ℃, and the air outlet temperature is preferably 70-120 ℃. The time for the drum drying or the spray drying is not particularly limited as long as a constant weight material can be obtained.

The invention also provides the emulsifier obtained by the preparation method in the technical scheme, wherein the viscosity of the emulsifier is 600-3000 mPa & s, and the mass content of octenyl succinic acid group is 2.5-3.5%; taking salad oil as an example, 1g of emulsifier emulsifies 8-40 g of salad oil.

The invention also provides the application of the macromolecular starch-based emulsifier in the technical scheme in the preparation of emulsion.

In the present invention, the emulsifier is a macromolecular starch-based emulsifier, or a mixture of a macromolecular starch-based emulsifier and a low viscosity octenyl succinic starch when preparing the emulsion. In the invention, when the macromolecular starch-based emulsifier is used as an emulsifier, the emulsifying agent has the advantages of less using amount and higher emulsifying performance compared with commercially available low-viscosity sodium starch octenyl succinate when high-fold oil or oil-soluble substances which are difficult to emulsify are emulsified; the emulsifying property of the starch can be improved by mixing the starch with low viscosity and octenyl succinic acid which is sold in the market according to a certain proportion, so that the adaptability is wider.

The macromolecular starch-based emulsifier provided by the present invention, and the preparation method and application thereof, will be described in detail with reference to the following examples, but they should not be construed as limiting the scope of the present invention.

Example 1

(1) Preparing an aqueous solution with the mass concentration of 40% by using water for the cassava starch, adding a hydrochloric acid aqueous solution with the mass concentration of 32% by weight of 2% by weight of the cassava starch, and reacting for 13 hours at the temperature of 45-50 ℃.

(2) Adjusting the pH of the obtained reaction liquid to 7.5-8.5 by using dilute alkali liquid (alkali is sodium hydroxide) with the mass concentration of 3%, uniformly dropwise adding octenyl succinic anhydride with the mass concentration of 3.0% of that of the cassava starch (the dropwise adding speed is 1g/min), after the dropwise adding of the octenyl succinic anhydride is finished, maintaining the temperature at 35-40 ℃ for esterification reaction for 10h, and adjusting the pH to 5.0-6.5 by using hydrochloric acid to obtain esterification reaction liquid.

(3) The esterification reaction liquid is subjected to rotational flow washing by adopting water, and the conductivity is controlled to be less than or equal to 500 mu s/cm²。

(4) Drying by adopting a roller drying mode, wherein the steam pressure of the roller drying is 0.50-0.65 MPa, and obtaining the emulsifier.

Indexes of the obtained emulsifier are as follows:

the viscosity of the obtained emulsifier is 2500 mPa.s; the fineness (80 meshes of pass rate) is 90 percent; the mass content of octenyl succinic acid group was 2.5%.

Test mode of emulsifying capacity for oil: taking salad oil as an example, 1g of the obtained emulsifier and 20g of salad oil are mixed uniformly, 79g of water is placed under an JRJ300-sh digital display shearing emulsifying stirrer, the mixture of the emulsifier and the salad oil is poured while stirring, and the mixture is stirred at the highest speed for 5min to form a uniform emulsion.

The results were: 1g of the resulting emulsifier can emulsify 20g of oil.

Emulsifying power of sodium starch octenyl succinate with a comparative viscosity of 100 mPas on oil: sodium starch octenyl succinate at 100 mPas was only able to emulsify 5g of oil.

Emulsion stability: heating the emulsion obtained by testing the emulsifying property of the emulsifier on oil at 95 ℃ for 10min, and avoiding demulsification; the demulsifying tall oil appears in the emulsifying system obtained by using the octenyl sodium starch succinate with the viscosity of 100 mPa.s.

Example 2

(1) Preparing an aqueous solution with the mass concentration of 40% by using water for the cassava starch, adding a hydrochloric acid aqueous solution with the mass concentration of 32% and the mass concentration of 2.0% by mass of the cassava starch, and reacting for 13 hours at the temperature of 45-50 ℃.

(2) And (3) adjusting the pH of the obtained reaction liquid to 6.5-7.5 by using a dilute alkali solution (alkali is sodium hydroxide) with the mass concentration of 3%, uniformly dropwise adding octenyl succinic anhydride with the mass concentration of 3.2% of the starch (the dropwise adding speed is 1g/min), maintaining the temperature at 35-40 ℃ for esterification reaction for 10 hours, and adjusting the pH to 5.0-6.5 by using hydrochloric acid to obtain an esterification reaction feed liquid.

(3) The esterification reaction liquid is subjected to rotational flow washing by adopting water, and the conductivity is controlled to be less than or equal to 500 mu s/cm²。

(4) Drying by adopting a roller drying mode, wherein the steam pressure of the roller drying is 0.50-0.65 MPa, and obtaining the emulsifier.

Indexes of the obtained emulsifier are as follows:

the viscosity of the obtained emulsifier is 2500 mPa.s; the fineness (80 meshes of pass rate) is 90 percent; the mass content of octenyl succinic acid group was 2.6%.

Emulsifying power for oil (salad oil as an example): 1g of the resulting emulsifier can emulsify 20g of oil.

Emulsion stability: the emulsion formed is heated for 10min at 95 ℃, and the emulsion breaking phenomenon does not occur.

Example 3

(1) Preparing waxy corn starch into a waxy corn starch aqueous solution with the mass concentration of 40% by using water, adjusting the pH value to 8.0-9.0 by using a dilute alkali solution (the alkali is sodium hydroxide) with the mass concentration of 3%, uniformly adding sodium hypochlorite (the effective chlorine concentration of the sodium hypochlorite is 12%) with the mass concentration of 25% by mass of the waxy corn starch, carrying out an oxidation reaction for 5 hours at the temperature of 35-40 ℃, and adjusting the pH value to 5.0-6.0 by using hydrochloric acid.

(2) And (3) adjusting the pH value of the feed liquid to 8.0-9.0 by using 3% of sodium hydroxide, uniformly and continuously adding octenyl succinic anhydride with the mass of 3.8% of the starch (the dropping speed is 1g/min), then carrying out esterification reaction for 10h at the temperature of 30-40 ℃, and adjusting the pH value to 5.5-6.5 by using hydrochloric acid.

(3) The esterification reaction liquid is subjected to rotational flow washing by adopting water, and the conductivity is controlled to be less than or equal to 500 mu s/cm²。

(4) Drying by adopting a roller drying mode, wherein the steam pressure of the roller drying is 0.45-0.60 MPa, and the temperature is 130-150 ℃, so as to obtain the emulsifier.

Indexes of the obtained emulsifier are as follows:

the viscosity of the obtained emulsifier is 2000 mPas; the fineness (80 meshes of pass rate) is 95 percent; the mass content of octenyl succinic acid group was 3.0%.

Emulsifying power for oil (salad oil as an example): 1g of the resulting emulsifier can emulsify 40g of oil.

Emulsion stability: the emulsion formed is heated for 10min at 95 ℃, and the emulsion breaking phenomenon does not occur.

10% salt was added to the above emulsion, and the emulsion was left in an oven at 60 ℃ for one month without oil slick or separation of the precipitate, whereas a system of sodium starch octenyl succinate made from the same raw material with a viscosity of 80 mPas and salad oil (1 g starch to 5g oil) exhibited oil slick on day 7.

Example 4

(1) Preparing cassava starch into a cassava starch aqueous solution with the mass concentration of 40% by using water, adjusting the pH value to 8.5-9.0 by using a dilute alkali solution (the alkali is sodium hydroxide) with the mass concentration of 3%, uniformly adding sodium hypochlorite (the effective chlorine concentration of the sodium hypochlorite is 12%) with the mass concentration of 20% of the cassava starch, carrying out oxidation reaction for 5 hours at the temperature of 35-40 ℃, and adjusting the pH value to 5.0-6.0 by using hydrochloric acid.

(2) Adjusting the pH of the obtained reaction liquid to 8.0-9.0 by using dilute alkali liquid (the alkali is sodium hydroxide) with the mass concentration of 3%, uniformly feeding octenyl succinic anhydride (the dropping speed is 1g/min) with the mass concentration of 3.0% of the cassava starch, after the dropping of the octenyl succinic anhydride is finished, carrying out esterification reaction for 10 hours at the temperature of 30-40 ℃, and adjusting the pH value to 5.0-6.0 by using hydrochloric acid.

(3) The esterification reaction liquid is subjected to rotational flow washing by adopting water, and the conductivity is controlled to be less than or equal to 500 mu s/cm²。

(4) Drying by adopting a roller drying mode, wherein the pressure of the roller drying is 0.5-0.7 MPa, and the temperature is 130-155 ℃, so as to obtain the emulsifier.

Indexes of the obtained emulsifier are as follows:

the viscosity of the obtained emulsifier is 3000 mPas; the fineness (80 meshes of pass rate) is 99 percent; the mass content of octenyl succinic acid group was 2.6%.

Emulsifying power for oil (salad oil as an example): 1g of the resulting emulsifier can emulsify 18g of oil.

Emulsifying power of sodium starch octenyl succinate with a contrast viscosity of 80mPa · s for oil: sodium starch octenyl succinate at 80 mPas was only able to emulsify 5g of oil.

Emulsion stability: the formed emulsion can not generate oil floating phenomenon and precipitate after being stored for one month under the 60 ℃ destruction experiment condition.

The control samples exhibited oil slick or sedimentation stratification.

Example 5

(1) Preparing cassava starch into a cassava starch aqueous solution with the mass concentration of 40% by using water, adjusting the pH value to 9.0-10.0 by using a dilute alkali solution with the mass concentration of 3% (the alkali is sodium hydroxide), uniformly adding hydrogen peroxide with the mass concentration of 25% of the cassava starch (the mass concentration of the hydrogen peroxide is 28%), after that, carrying out oxidation reaction for 5h under the condition of 35-40 ℃, and adjusting the pH value to 5.0-6.0 by using hydrochloric acid.

(2) Adjusting the pH value of the feed liquid to 7.5-8.5 by using 3% of sodium hydroxide, uniformly and continuously adding octenyl succinic anhydride with the mass of 3.2% of that of the cassava starch (the dropping speed is 1g/min), then carrying out esterification reaction for 10h at the temperature of 30-40 ℃, and adjusting the pH value to 5.0-6.0 by using hydrochloric acid.

(3) The esterification reaction liquid is subjected to rotational flow washing by adopting water, and the conductivity is controlled to be less than or equal to 500 mu s/cm²。

(4) Drying by adopting a roller drying mode, wherein the pressure of the roller drying is 0.5-0.7 MPa, and the temperature is 130-155 ℃, so as to obtain the emulsifier.

Indexes of the obtained emulsifier are as follows:

the viscosity of the obtained emulsifier is 2500 mPa.s; fineness (80 mesh pass rate) 95%; the octenyl succinic acid group content was 2.6%.

Emulsifying power for oil (salad oil as an example): 1 gram of the oil can be emulsified with 18 grams of oil.

Emulsion stability: the emulsion formed is heated for 10min at 95 ℃, and the emulsion breaking phenomenon does not occur.

Example 6

(1) Preparing 1kg of cassava starch into a cassava starch aqueous solution with the mass concentration of 35% by using water, adding 1mL of maltase, carrying out enzymolysis for 5 hours at the temperature of 50-65 ℃, adjusting the pH to be below 4.5, and inactivating the enzyme for 0.5 hour.

(2) And after the treated starch solution is cooled to normal temperature, adjusting the pH to 7.5-8.5 by using dilute alkali liquor (alkali is sodium hydroxide) with the mass concentration of 3%, uniformly feeding octenyl succinic anhydride with the mass concentration of 3.5% of the starch (the dropping speed is 1g/min), performing esterification reaction at the temperature of 30-40 ℃ for 10h, and adjusting the pH value to 4.5-5.5 by using hydrochloric acid.

(3) Precipitating and filtering the esterification reaction feed liquid twice by using 75% alcohol; then, distilled water is used again to prepare 35% solution.

(4) Drying is carried out by adopting a spray drying mode, wherein the air inlet temperature is 190-240 ℃, and the air outlet temperature is 100-120 ℃.

Indexes of the obtained emulsifier are as follows:

the viscosity of the obtained emulsifier is 1200 mPas; the fineness (100 meshes of pass rate) is 95 percent; the mass content of octenyl succinic acid group was 2.7%.

Emulsifying power for oil (salad oil as an example): 1g of the resulting emulsifier can emulsify 8g of oil.

Emulsion stability: the emulsion formed is heated for 10min at 95 ℃, and the emulsion breaking phenomenon does not occur.

Example 7

(1) Preparing waxy corn starch into a solution with the mass concentration of 35% by using water, adding maltase according to the proportion of 1mL/kg starch, performing enzymolysis for 5 hours at the temperature of 55-65 ℃, adjusting the pH to be below 4.5, and keeping for 1 hour for enzyme deactivation;

(2) adjusting the pH value of the obtained reaction liquid to 8.0-9.0 by using dilute alkali liquid (the alkali is sodium hydroxide) with the mass concentration of 3%, uniformly and continuously adding octenyl succinic anhydride with the mass concentration of 4% of the starch (the dropping speed is 1g/min), then carrying out esterification reaction for 10h at the temperature of 30-40 ℃, and adjusting the pH value to 5.5-6.0 by using hydrochloric acid;

(3) filtering the esterification reaction feed liquid twice by using 75% alcohol; then, distilled water is used again to prepare 35% solution.

(4) And drying in a spray drying mode, wherein the air inlet temperature is 190-240 ℃, the air outlet temperature is 100-120 ℃, and the emulsifier is obtained.

Indexes of the obtained emulsifier are as follows:

the viscosity of the obtained emulsifier is 800 mPas; the fineness (80 meshes of pass rate) is 96 percent; the mass content of octenyl succinic acid group was 2.9%.

Emulsifying power for oil (salad oil as an example): 1g of the resulting emulsifier can emulsify 12g of oil.

Emulsion stability: the emulsion formed is heated for 10min at 95 ℃, and the emulsion breaking phenomenon does not occur.

Example 8

The emulsifier obtained in example 3 and imported low-viscosity sodium octenyl succinate starch (viscosity of 100mPa · s) were mixed in a mass ratio of 3: and 7, mixing by using an airflow mixer to obtain the composite emulsifier.

Indexes of the obtained composite emulsifier are as follows:

the viscosity of the obtained composite emulsifier is 650 mPas; the fineness (80 meshes of pass rate) is 95 percent; the mass content of octenyl succinic acid group was 2.7%.

Emulsifying power for oil (salad oil as an example): 1g of the obtained composite emulsifier can emulsify 8g of oil.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.