Emulsifying agent for food processing

Abstract

The invention relates to an emulsifier for food processing, and belongs to the technical field of emulsifiers. The emulsifier disclosed by the invention simultaneously contains a hydrophobic triglyceride group, a neutral aliphatic chain linking group and a citric acid monoester amphiphilic group, a carboxylic acid group in the citric acid monoester amphiphilic group is close to a water phase due to strong affinity with the water phase, and the carboxylic acid group and water form a hydrogen bond to be adsorbed and combined with water molecules; ester groups in hydrophobic triglyceride groups and citric acid monoester amphiphilic groups are close to an oil phase due to strong affinity with the oil phase, a neutral aliphatic chain connecting group plays a transition role, groups at two ends of an emulsifier molecule pull the oil phase and a water phase together to form an emulsion in the stirring and emulsifying process, and after stirring is finished, the emulsifier is prepared. The hydrophobic triglyceride group, the neutral aliphatic chain linking group and the citric acid monoester amphiphilic group play a stepped hydrophilic and oleophylic role in the emulsion, so that an oil phase and a water phase are firmly combined together without layering and demulsification.

Description

Technical Field

[0001] The invention relates to an emulsifier for food processing, belonging to the technical field of emulsifiers. Background Art

[0002] Food emulsifiers are multifunctional additives used in the food processing process to simplify process operations, improve quality, extend food storage period, and improve the color, aroma, and taste of food. The molecules of food emulsifiers are composed of two parts: a hydrophilic group and a hydrophobic group. Compounds composed of two parts, a hydrophilic group and a lipophilic group, are called amphiphilic compounds. The presence of hydrophilic and lipophilic groups in the same molecule of food emulsifier can make the molecule of food emulsifier have a certain surface activity. The lipophilic group in the food emulsifier is similar to the long-chain alkane in the structure of oils and fats, so the alkane in the emulsifier can be miscible with oils and fats, and the hydrophilic group in the emulsifier has more or less hydroxyl groups with water and water-soluble substances, which can be compatible with each other. Food emulsifiers can form an adsorption layer at the interface of water and oil, connecting the two and playing an emulsifying role. Due to these surface active effects and special functions in food, emulsifiers are widely used in the field of food processing. Their main application areas include baked foods (such as bread, cakes and various snacks), dairy products, frozen foods, beverages and alcoholic beverages, as well as processed foods such as candy, oils, and noodles.

[0003] At present, the commonly used emulsifiers for food processing mainly include glycerol fatty acid esters, sucrose fatty acid esters, lecithin and its derivatives, sorbitol fatty acid esters and propylene glycol fatty acid esters. Due to the complexity of food ingredients, food emulsifiers involved in the formation of emulsions are often required to have good compatibility with other food ingredients. However, due to structural limitations, most of the commonly used emulsifiers for food processing can only emulsify one or more food oil phases well, and their adaptability is relatively narrow. And as people pay more attention to food safety issues, the problem of excessive additives caused by the general emulsification effect of conventional emulsifiers needs to be solved urgently. Summary of the invention

[0004] The object of the present invention is to provide an emulsifier for food processing, so as to solve the problem that conventional emulsifiers have a general emulsifying effect and need to be added in large quantities during use, resulting in excessive additives.

[0005] The present invention provides an emulsifier for food processing, which is prepared by a method comprising the following steps:

[0006] (1) React a diglyceride and an acid anhydride compound to obtain a glyceride carboxylic acid compound; the molar ratio of the diglyceride to the acid anhydride compound is 1:1. The diglyceride is dilaurin, dimyristin, diolein or dicaprylin, and the acid anhydride compound is 3-methylhexahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydro-4-methylphthalic anhydride, hexahydrophthalic anhydride, succinic anhydride or adipic anhydride;

[0007] (2) React the glyceride carboxylic acid compound with thionyl chloride to obtain a glyceride acyl chloride compound;

[0008] (3) React the glyceride acyl chloride compound with a citric acid monoester to obtain an emulsifier for food processing; the citric acid monoester is prepared by reacting citric anhydride with an alcohol compound, and the alcohol compound is lauryl alcohol, 1-undecanol, nonanol, n-octanol or pentadecanol.

[0009] Preferably, the diglyceride is dilaurin, the acid anhydride compound is 3-methylhexahydrophthalic anhydride, and the alcohol compound is lauryl alcohol.

[0010] Preferably, the reaction temperature of the diglyceride and the acid anhydride compound is 50 - 70 °C, and the reaction time is 6 - 8 h.

[0011] Preferably, the mass ratio of the glyceride carboxylic acid compound to thionyl chloride is 1:6 - 8.

[0012] Preferably, the reaction of the glyceride carboxylic acid compound with thionyl chloride is carried out under reflux conditions, and the reaction time is 8 - 10 h.

[0013] Preferably, the molar ratio of citric anhydride to the alcohol compound is 1:1.

[0014] Preferably, the reaction temperature of citric anhydride and the alcohol compound is 80 - 85 °C, and the reaction time is 5 - 7 h.

[0015] Preferably, the molar ratio of the glyceride acyl chloride compound to the citric acid monoester is 1:1.

[0016] Preferably, the reaction temperature of the glyceride acyl chloride compound and the citric acid monoester is 0 - 5 °C, and the reaction time is 8 - 10 h.

[0017] Preferably, the emulsifier for food processing has the following structure:

[0018]

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) The emulsifier of the present invention contains a hydrophobic triglyceride group, a neutral fatty acid chain linking group, and a citric acid monoester amphiphilic group at the same time. The citric acid monoester amphiphilic group contains a hydrophilic carboxylic acid group and a hydrophobic citric acid ester group at the same time. When the emulsifier is used to disperse and emulsify the oil phase and the water phase, the carboxylic acid group in the citric acid monoester amphiphilic group is close to the water phase due to its strong affinity with water, and the carboxyl group forms a hydrogen bond with water and adsorbs and combines with water molecules. The hydrophobic triglyceride group and the ester group in the citric acid monoester amphiphilic group are close to the oil phase due to their strong affinity with oil, and the neutral fatty acid chain linking group plays a transitional role. During the stirring and emulsifying process, the groups at both ends of the emulsifier molecule pull the oil phase and the water phase together to form an emulsion. After the stirring is completed, the hydrophobic triglyceride group, the neutral fatty acid chain linking group, and the citric acid monoester amphiphilic group play a stepped hydrophilic-lipophilic role in the emulsion, making the oil phase and the water phase firmly combined together without delamination and demulsification.

[0021] (2) The emulsifier prepared by the present invention has good emulsifying ability and emulsifying stability for vegetable oil, oleic acid, and cream. When used to emulsify peanut oil and water, the emulsifying ability is greater than 101 min, and the stability is less than 19 mL. When used to emulsify oleic acid and water, the emulsifying ability is greater than 95 min, and the stability is less than 20 mL. When used to emulsify cream and water, the emulsifying ability is greater than 91 min, and the stability is less than 20 mL. The emulsifying ability and emulsifying stability of the emulsifier prepared by the present invention are far superior to those of conventional emulsifiers such as monoglyceride stearate, diglycerol laurate, and mono- and diglycerol diacetyl tartrate. Description of the Drawings

[0022] Figure 1 It is the nuclear magnetic hydrogen spectrum of the food processing emulsifier prepared in Example 2 of the present invention. Detailed Embodiments

[0023] The following examples are intended to further illustrate the content of the present invention rather than limit the protection scope of the present invention.

[0024] Specific examples of the food processing emulsifier and its preparation method of the present invention are as follows:

[0025] Example 1

[0026] The food processing emulsifier of this example has the following structure:

[0027]

[0028] Example 2

[0029] This example is the preparation method of the food processing emulsifier of Example 1, including the following steps:

[0030] (1) Add diglyceride, acid anhydride compound and chloroform into a reaction kettle, then heat the materials in the reaction kettle to 50 °C, stir and react for 6 h, and remove the solvent chloroform by vacuum distillation to obtain a glycerol ester carboxylic acid compound. Among them, the molar ratio of diglyceride to acid anhydride compound is 1:1, the diglyceride is dilaurin, the acid anhydride compound is hexahydro-4-methylphthalic anhydride, and the mass of chloroform is 50% of the sum of the masses of diglyceride and acid anhydride compound. The structure of hexahydro-4-methylphthalic anhydride is as follows:

[0031]

[0032] (2) Add the glycerol ester carboxylic acid compound prepared in step (1) and thionyl chloride into a reaction kettle, then heat the materials in the reaction kettle to reflux, stir and reflux for 8 h, and remove the unreacted thionyl chloride by vacuum distillation to obtain a glycerol ester acyl chloride compound. Among them, the mass ratio of glycerol ester carboxylic acid compound to thionyl chloride is 1:6.

[0033] (3) Add an alcohol compound and ethyl acetate into a reaction kettle, stir evenly, then add citric anhydride into the reaction kettle, and then heat the materials in the reaction kettle to 80 °C, stir and react for 5 h, and remove the solvent ethyl acetate by vacuum distillation to obtain a citric acid monoester. Among them, the molar ratio of the alcohol compound to citric anhydride is 1:1, and the mass of ethyl acetate is 40% of the sum of the masses of the alcohol compound and citric anhydride. Among them, the alcohol compound is lauryl alcohol.

[0034] (4) Stir the glycerol ester acyl chloride compound prepared in step (2) and dichloromethane evenly to obtain a glycerol ester acyl chloride compound solution (mass fraction 30%); stir the citric acid monoester and dichloromethane evenly to obtain a citric acid monoester solution (mass fraction 50%); add the citric acid monoester solution into a reaction kettle, adjust the temperature of the materials in the reaction kettle to 0 °C, start stirring, and dropwise add the glycerol ester acyl chloride compound solution into the reaction kettle. After the dropping is completed, add triethylamine into the reaction kettle, adjust the materials in the reaction kettle to room temperature, continue to stir and react for 8 h, filter, and subject the filtrate to vacuum distillation to remove the solvent to obtain a food emulsifier. Among them, the molar ratio of glycerol ester acyl chloride compound, citric acid monoester and triethylamine is 1:1:1.2. The nuclear magnetic resonance hydrogen spectrum of the food emulsifier prepared in this example is as Figure 1 shown.

[0035] Example 3

[0036] This example is a preparation method of an emulsifier for food processing in Example 1, including the following steps:

[0037] (1) Add diglyceride, acid anhydride compound and chloroform into a reaction kettle, then heat the materials in the reaction kettle to 60 °C, stir and react for 7 h, and remove the solvent chloroform by vacuum distillation to obtain a glyceride carboxylic acid compound. Among them, the molar ratio of diglyceride to acid anhydride compound is 1:1, the diglyceride is dilaurin, the acid anhydride compound is hexahydro-4-methylphthalic anhydride, and the mass of chloroform is 55% of the sum of the masses of diglyceride and acid anhydride compound.

[0038] (2) Add the glyceride carboxylic acid compound prepared in step (1) and thionyl chloride into a reaction kettle, then heat the materials in the reaction kettle to reflux, stir and reflux for 9 h, and remove the unreacted thionyl chloride by vacuum distillation to obtain a glyceride acyl chloride compound. Among them, the mass ratio of glyceride carboxylic acid compound to thionyl chloride is 1:7.

[0039] (3) Add an alcohol compound and ethyl acetate into a reaction kettle, stir evenly, then add citric anhydride into the reaction kettle, and then heat the materials in the reaction kettle to 82 °C, stir and react for 6 h, and remove the solvent ethyl acetate by vacuum distillation to obtain a citric acid monoester. Among them, the molar ratio of alcohol compound to citric anhydride is 1:1, and the mass of ethyl acetate is 42% of the sum of the masses of alcohol compound and citric anhydride. Among them, the alcohol compound is lauryl alcohol.

[0040] (4) Stir the glyceride acyl chloride compound prepared in step (2) and dichloromethane evenly to obtain a glyceride acyl chloride compound solution (mass fraction 35%); stir the citric acid monoester and dichloromethane evenly to obtain a citric acid monoester solution (mass fraction 55%); add the citric acid monoester solution into a reaction kettle, adjust the temperature of the materials in the reaction kettle to 2 °C, start stirring, and dropwise add the glyceride acyl chloride compound solution into the reaction kettle. After the dropping is completed, add triethylamine into the reaction kettle, adjust the materials in the reaction kettle to room temperature, continue to stir and react for 9 h, filter, and distill the filtrate under reduced pressure to remove the solvent to obtain a food emulsifier. Among them, the molar ratio of glyceride acyl chloride compound, citric acid monoester and triethylamine is 1:1:1.3.

[0041] Example 4

[0042] The preparation method of the emulsifier for food processing in this example is the same as that in Example 1, including the following steps:

[0043] (1) Add diglyceride, acid anhydride compound and chloroform into a reaction kettle, then heat the materials in the reaction kettle to 70 °C, stir and react for 8 h, and remove the solvent chloroform by vacuum distillation to obtain a glyceride carboxylic acid compound. Among them, the molar ratio of diglyceride to acid anhydride compound is 1:1, the diglyceride is dilaurin, the acid anhydride compound is hexahydro-4-methylphthalic anhydride, and the mass of chloroform is 60% of the sum of the masses of diglyceride and acid anhydride compound.

[0044] (2) Add the glyceride carboxylic acid compound prepared in step (1) and thionyl chloride into a reaction kettle, then heat the materials in the reaction kettle to reflux, stir and reflux for 10 h, and distill off the unreacted thionyl chloride under reduced pressure to obtain a glyceride acyl chloride compound. Among them, the mass ratio of the glyceride carboxylic acid compound to thionyl chloride is 1:8.

[0045] (3) Add the alcohol compound and ethyl acetate into a reaction kettle, stir evenly, then add citric anhydride into the reaction kettle, and then heat the materials in the reaction kettle to 85 °C, stir and react for 7 h, and distill off the solvent ethyl acetate under reduced pressure to obtain a citric acid monoester. Among them, the molar ratio of the alcohol compound to citric anhydride is 1:1, and the mass of ethyl acetate is 45% of the sum of the masses of the alcohol compound and citric anhydride. Among them, the alcohol compound is lauryl alcohol.

[0046] (4) Stir the glyceride acyl chloride compound prepared in step (2) and dichloromethane evenly to obtain a glyceride acyl chloride compound solution (mass fraction 40%); stir the citric acid monoester and dichloromethane evenly to obtain a citric acid monoester solution (mass fraction 60%); add the citric acid monoester solution into a reaction kettle, adjust the temperature of the materials in the reaction kettle to 5 °C, start stirring, and dropwise add the glyceride acyl chloride compound solution into the reaction kettle. After the dropping is completed, add triethylamine into the reaction kettle, adjust the materials in the reaction kettle to room temperature, continue to stir and react for 10 h, filter, and distill the filtrate under reduced pressure to remove the solvent to obtain a food emulsifier. Among them, the molar ratio of the glyceride acyl chloride compound, citric acid monoester and triethylamine is 1:1:1.4.

[0047] Example 5

[0048] The difference between the preparation method of the food processing emulsifier in this example and the preparation method of the food processing emulsifier in Example 2 is only that the diglyceride in step (1) of the preparation method of the food processing emulsifier in this example is dipalmitoyl glycerol.

[0049] Example 6

[0050] The difference between the preparation method of the food processing emulsifier in this example and the preparation method of the food processing emulsifier in Example 2 is only that the diglyceride in step (1) of the preparation method of the food processing emulsifier in this example is dioleoyl glycerol.

[0051] Example 7

[0052] The difference between the preparation method of the food processing emulsifier in this example and the preparation method of the food processing emulsifier in Example 2 is only that the diglyceride in step (1) of the preparation method of the food processing emulsifier in this example is dicaprylyl glycerol.

[0053] Example 8

[0054] The preparation method of the emulsifier for food processing in this example is only different from that in Example 2 in that the anhydride compound in step (1) of the preparation method of the emulsifier for food processing in this example is 3-methylhexahydrophthalic anhydride. The structure of 3-methylhexahydrophthalic anhydride is as follows:

[0055]

[0056] Example 9

[0057] The preparation method of the emulsifier for food processing in this example is only different from that in Example 2 in that the anhydride compound in step (1) of the preparation method of the emulsifier for food processing in this example is methylhexahydrophthalic anhydride. The structure of methylhexahydrophthalic anhydride is as follows:

[0058]

[0059] Example 10

[0060] The preparation method of the emulsifier for food processing in this example is only different from that in Example 2 in that the anhydride compound in step (1) of the preparation method of the emulsifier for food processing in this example is hexahydrophthalic anhydride. The structure of hexahydrophthalic anhydride is as follows:

[0061]

[0062] Example 11

[0063] The preparation method of the emulsifier for food processing in this example is only different from that in Example 2 in that the anhydride compound in step (1) of the preparation method of the emulsifier for food processing in this example is succinic anhydride. The structure of succinic anhydride is as follows:

[0064]

[0065] Example 12

[0066] The preparation method of the emulsifier for food processing in this example is only different from that in Example 2 in that the anhydride compound in step (1) of the preparation method of the emulsifier for food processing in this example is adipic anhydride. The structure of adipic anhydride is as follows:

[0067]

[0068] Example 13

[0069] The preparation method of the emulsifier for food processing in this example is only different from that of the emulsifier for food processing in Example 2 in that the alcohol compound in step (3) of the preparation method of the emulsifier for food processing in this example is 1-undecanol.

[0070] Example 14

[0071] The preparation method of the emulsifier for food processing in this example is only different from that of the emulsifier for food processing in Example 2 in that the alcohol compound in step (3) of the preparation method of the emulsifier for food processing in this example is nonanol.

[0072] Example 15

[0073] The preparation method of the emulsifier for food processing in this example is only different from that of the emulsifier for food processing in Example 2 in that the alcohol compound in step (3) of the preparation method of the emulsifier for food processing in this example is n-octanol.

[0074] Example 16

[0075] The preparation method of the emulsifier for food processing in this example is only different from that of the emulsifier for food processing in Example 2 in that the alcohol compound in step (3) of the preparation method of the emulsifier for food processing in this example is pentadecanol.

[0076] Comparative Example 1

[0077] The emulsifier for food processing in this comparative example is monoglyceride stearate.

[0078] Comparative Example 2

[0079] The emulsifier for food processing in this comparative example is diglycerol laurate.

[0080] Comparative Example 3

[0081] The emulsifier for food processing in this comparative example is mono- and diglycerol diacetyl tartrate, and the manufacturer is Ningbo Beilun Yaxu Chemical Co., Ltd.

[0082] Comparative Example 4

[0083] The preparation method of the emulsifier for food processing in this comparative example is only different from that of the emulsifier for food processing in Example 2 in that citric acid is used to replace citric acid monoester in step (4) of the preparation method of the emulsifier for food processing in this comparative example.

[0084] Effect Example

[0085] To evaluate the emulsifying properties of the emulsifiers prepared in each example and comparative example, 0.1 g of the emulsifier was added to a conical flask, and then 25 mL of water and 25 mL of the oil-phase test solution (the oil-phase test solution was peanut oil, oleic acid, or cream, and the freezing point of cream was 20 °C) were added. After stirring evenly at 65 °C, an emulsion was obtained. Then, the emulsion was poured into a graduated cylinder, and the graduated cylinder was placed in a constant-temperature environment at 25 °C. The emulsion in the graduated cylinder gradually separated into layers. Record the time t when the volume of the aqueous phase in the emulsion layer reached 5 mL and the volume V of the aqueous phase after standing for 30 h. The time t was used to evaluate the emulsifying ability of the emulsifier, and the volume V of the aqueous phase was used to evaluate the emulsifying stability of the emulsifier. The test results of the emulsifying properties of the emulsifiers prepared in each example and comparative example are shown in Table 1.

[0086] Table 1 Emulsifying properties of the emulsifiers prepared in each example and comparative example

[0087]

[0088]

[0089] As can be seen from Table 1, the emulsifiers prepared by the present invention have good emulsifying ability and emulsifying stability for vegetable oil, oleic acid, and cream. When used to emulsify peanut oil and water, the emulsifying ability is greater than 101 min, and the stability is less than 19 mL. When used to emulsify oleic acid and water, the emulsifying ability is greater than 95 min, and the stability is less than 20 mL. When used to emulsify cream and water, the emulsifying ability is greater than 91 min, and the stability is less than 20 mL. The emulsifying ability and emulsifying stability of the emulsifiers prepared by the present invention are far superior to those of conventional emulsifiers such as monoglyceride stearate, diglycerol laurate, and mono- and diglycerol diacetyl tartrate.

[0090] Since the emulsifier of the present invention contains both a hydrophobic triglyceride group, a neutral fatty acid chain linking group, and a citric acid monoester amphiphilic group, and the citric acid monoester amphiphilic group contains both a hydrophilic carboxylic acid group and a hydrophobic citric acid ester group. When the emulsifier is used to disperse and emulsify the oil phase and the water phase, the carboxylic acid group in the citric acid monoester amphiphilic group is close to the water phase due to its strong affinity for water, and the carboxyl group forms a hydrogen bond with water and adsorbs and binds to the water molecules. The hydrophobic triglyceride group and the ester group in the citric acid monoester amphiphilic group are close to the oil phase due to their strong affinity for oil, and the neutral fatty acid chain linking group plays a transitional role. During the stirring and emulsifying process, the groups at both ends of the emulsifier molecule pull the oil phase and the water phase together to form an emulsion. After the stirring is completed, the hydrophobic triglyceride group, the neutral fatty acid chain linking group, and the citric acid monoester amphiphilic group play a stepped hydrophilic-lipophilic role in the emulsion, making the oil phase and the water phase firmly combined together without separating and breaking.

[0091] As can be seen from Example 1 and Examples 5 - 7, the length of the ester group carbon chain in diglyceride affects the emulsifying effect of the emulsifier. As the carbon chain length increases, the emulsifying performance shows a trend of first improving, then deteriorating, and then improving again. When the number of carbon atoms in the carbon chain is 12, the emulsifying performance of the emulsifier reaches the optimum. This may be because when the length of the ester group carbon chain in diglyceride is too small, the lipophilicity of the ester group is relatively small, which does not match the hydrophilicity of the amphiphilic groups of citric acid monoester, causing the emulsifier to migrate too much towards the water phase, resulting in poor binding force between the oil phase and the water phase. When the length of the ester group carbon chain in diglyceride is too large, the lipophilicity of the ester group is too strong, weakening the affinity between the amphiphilic groups of citric acid monoester and the water phase, causing the emulsifier to migrate too much towards the oil phase, leading to a poor emulsifying effect.

[0092] As can be seen from Example 1 and Examples 8 - 12, when the neutral fatty acid chain linking group is a hexahydro - 4 - methylphthalene group, the emulsifier has the best emulsifying effect on peanut oil, oleic acid, and cream. This may be because compared with the 3 - methylhexahydrophthalene group, methylhexahydrophthalene group, hexahydrophthalene group, butanediyl group, and hexanediyl group, the hexahydro - 4 - methylphthalene group has a cyclic structure, with a relatively large steric hindrance and contact area, and there is a methyl group at the distal end of the ring, which can further increase the steric hindrance and contact area. The large steric hindrance can slow down the diffusion and movement of the emulsifier, slowing down the separation of the oil phase and the water phase. The relatively large contact area allows the neutral fatty acid chain linking group to contact more water - phase molecules and oil - phase molecules, improving the adsorption stability, thereby improving the emulsifying effect.

[0093] As can be seen from Example 1 and Examples 13 - 16, the ester group carbon chain in the hydrophobic citric acid ester group affects the emulsifying effect of the emulsifier. When used to emulsify peanut oil and cream, as the ester group carbon chain length increases, the emulsifying effect shows a trend of first improving and then deteriorating. When used to emulsify oleic acid, as the ester group carbon chain length increases, the emulsifying effect shows a trend of first improving, then deteriorating, and then improving again. However, when used to emulsify peanut oil, oleic acid, and cream, the number of carbon atoms in the ester group carbon chain of the hydrophobic citric acid ester group with the best emulsifying effect is 12. This may be because when the number of carbon atoms in the ester group carbon chain of the hydrophobic citric acid ester group is equal to the number of carbon atoms in the ester group carbon chain in diglyceride, the coordination and matching balance between the two is better. When used for dispersion and emulsification, both ends of the emulsifier molecule have similar lipophilicity, and one end of the citric acid ester group also has hydrophilicity. The two cooperate with the intermediate neutral fatty acid chain linking group to achieve good emulsification of different oil phases.

[0094] As can be seen from Example 1 and Comparative Example 4, after replacing citric acid monoester with citric acid, due to the lack of an ester group in the citric acid group, its hydrophilicity is too strong and its lipophilicity is lacking, resulting in an imbalance between the hydrophilicity and lipophilicity of the emulsifier and a poor emulsifying effect.

Claims

1. An emulsifier for food processing, characterized in that, Prepared by a method comprising the following steps: (1) React a diglyceride and an acid anhydride compound to obtain a glycerol ester carboxylic acid compound; the molar ratio of the diglyceride to the acid anhydride compound is 1:1, the diglyceride is dilaurin, dimyristin, diolein or dicaprylin, and the acid anhydride compound is 3-methylhexahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydro-4-methylphthalic anhydride, hexahydrophthalic anhydride, succinic anhydride or adipic anhydride; (2) React the glycerol ester carboxylic acid compound with thionyl chloride to obtain a glycerol ester acyl chloride compound; (3) React the glycerol ester acyl chloride compound with a citric acid monoester to obtain an emulsifier for food processing; the citric acid monoester is prepared by reacting citric anhydride with an alcohol compound, and the alcohol compound is lauryl alcohol, 1-undecanol, nonyl alcohol, n-octanol or pentadecanol.

2. The emulsifier for food processing according to claim 1, characterized in that, The diglyceride is dilaurin, the acid anhydride compound is 3-methylhexahydrophthalic anhydride, and the alcohol compound is lauryl alcohol.

3. The emulsifier for food processing according to claim 1 or 2, characterized in that, The reaction temperature of the diglyceride and the acid anhydride compound is 50-70 °C, and the time is 6-8 h.

4. The emulsifier for food processing according to claim 1 or 2, characterized in that, The mass ratio of the glycerol ester carboxylic acid compound to thionyl chloride is 1:6-8.

5. The emulsifier for food processing according to claim 1 or 2, characterized in that, The reaction of the glycerol ester carboxylic acid compound and thionyl chloride is carried out under reflux conditions, and the reaction time is 8-10 h.

6. The emulsifier for food processing according to claim 1 or 2, characterized in that, The molar ratio of citric anhydride to the alcohol compound is 1:

1.

7. The emulsifier for food processing according to claim 1 or 2, characterized in that, The reaction temperature of citric anhydride and the alcohol compound is 80-85 °C, and the time is 5-7 h.

8. The emulsifier for food processing according to claim 1 or 2, characterized in that, The molar ratio of the glycerol ester acyl chloride compound to the citric acid monoester is 1:

1.

9. The emulsifier for food processing according to claim 1 or 2, characterized in that, The reaction temperature of the glycerol ester acyl chloride compound and the citric acid monoester is 0-5 °C, and the time is 8-10 h.

10. The emulsifier for food processing according to claim 1 or 2, characterized in that, The emulsifier for food processing has the following structure:

Images