阅读说明：本技术 一种改性淀粉-脂质二元复合物的高效制备方法 (Efficient preparation method of modified starch-lipid binary compound ) 是由 王书军 王晋伟 任菲 晁琛 于 2021-10-08 设计创作，主要内容包括：本发明提供一种改性淀粉-脂质二元复合物的高效制备方法,该制备方法包括：通过辛烯基琥珀酸酐对常规淀粉进行化学改性,使其具有优良的乳化性能；以辛烯基琥珀酸淀粉酯和脂质(棕榈酸,单棕榈酸甘油酯,二棕榈酸甘油酯)为原料,二者质量配比为10～200:1,配成浓度为7～20％的淀粉悬浮液,通过水相体系可以高效制备淀粉-脂质二元复合物。本发明提供的制备方法在食品加工过程中,可以有效促进淀粉与甘油二酯的复合。基于本发明制备出的具有特定理化性质和营养功能的淀粉-脂质复合物,相比于传统工艺,效率更高,品质更好,更加有利于食品品质的提升及对人体营养健康的调节改善。(The invention provides a high-efficiency preparation method of a modified starch-lipid binary compound, which comprises the following steps: the conventional starch is chemically modified by the octenyl succinic anhydride, so that the starch has excellent emulsifying property; starch octenyl succinate starch ester and lipid (palmitic acid, monopalmitin and dipalmitin) are used as raw materials, the mass ratio of the starch octenyl succinate starch ester to the lipid is 10-200: 1, a starch suspension with the concentration of 7-20% is prepared, and the starch-lipid binary compound can be efficiently prepared through an aqueous phase system. The preparation method provided by the invention can effectively promote the compounding of starch and diglyceride in the food processing process. Compared with the traditional process, the starch-lipid complex with specific physicochemical properties and nutritional functions, prepared by the method, has higher efficiency and better quality, and is more beneficial to the improvement of food quality and the regulation and improvement of human nutrition and health.)

1. The efficient preparation method of the modified starch-lipid binary compound is characterized by comprising the following steps of:

(1) preparing conventional corn starch into 10 wt% starch milk by using ionic liquid composite liquid; then, adjusting the pH value of the system to be alkalescent; at room temperature, dropwise adding octenyl succinic anhydride into the starch milk to perform esterification modification, keeping the pH value of the reaction system to be alkalescent, and continuously stirring; after the reaction is finished, adjusting the pH value of the system to be weakly acidic; then centrifuging, washing and drying to obtain octenyl succinic acid starch ester;

(2) adding the octenyl succinic anhydride modified starch obtained in the step (1) into deionized water, stirring to prepare a suspension of 7-20 wt%, then adding lipid, wherein the mass ratio of the lipid to the modified starch is 1: 10-200, and fully and uniformly stirring to obtain a modified starch-lipid suspension;

(3) and (3) heating the modified starch-lipid suspension obtained in the step (2) in a precise temperature-controlled magnetic stirring water bath until the starch is completely gelatinized, cooling to obtain a compound, and freeze-drying and grinding to obtain the binary compound of the octenyl succinic anhydride modified starch and the lipid.

2. The method for efficiently preparing the modified starch-lipid binary complex according to claim 1, wherein in the step (1), the corn starch is blended into 10 wt% of starch milk by using the prepared ionic liquid complex; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; respectively weighing octenyl succinic anhydride with the mass of 1-9% of the dry basis of the starch, and adding starch milk dropwise within 2.5h at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

3. The method for efficiently preparing the modified starch-lipid binary complex as claimed in claim 2, wherein the ionic liquid complex liquid is prepared by mixing 1-ethyl-3-methylimidazolium acetate ionic liquid and water in a mass ratio of 2: 8.

4. The method for efficiently preparing a modified starch-lipid binary complex according to claim 1, wherein the starch octenyl succinate obtained in step (2) is added into deionized water, and the mixture is premixed for 3min at a stirring speed of 200rpm to prepare a starch suspension with a concentration of 8 wt%; then adding lipid, wherein the mass ratio of the lipid to the modified starch is 1:200, 1:40, 1:20 and 1:10 on a dry basis, and stirring for 2min at the speed of 260 rpm.

5. The method for preparing the modified starch-lipid binary complex with high efficiency as claimed in claim 4, wherein the lipid is long-chain fatty acid or glyceride.

6. The method for efficiently preparing the modified starch-lipid binary complex according to claim 5, wherein the long-chain fatty acid is palmitic acid, and the glyceride is monopalmitin or dipalmitin.

7. The method for efficiently preparing the modified starch-lipid binary complex according to claim 1, wherein the preparation method in step (3) comprises the following steps: preheating and uniformly mixing, namely preheating and stirring the modified starch-lipid suspension for 2min at 50 ℃ by using a precise temperature control system, wherein the stirring speed is 200 rpm; heating up to 100 ℃ at a heating rate of 25 ℃/min, carrying out composite reaction for 1h, and stirring at a speed of 260 rpm; thirdly, a cooling forming stage, cooling the temperature to 25 ℃ at a cooling rate of 10 ℃/min, and stirring at a speed of 100 rpm; and fourthly, in the stage of sample processing, quickly placing the obtained pasty sample of the modified starch-lipid compound in liquid nitrogen for cooling for 5min, after freeze drying for 24h, grinding for 10min by using a high-throughput liquid nitrogen freeze grinding instrument under the condition of a rotating speed of 10cps, enabling the pasty sample of the modified starch-lipid compound to pass through a 100-mesh screen, and obtaining the binary compound of the octenyl succinic anhydride modified starch and the lipid.

Technical Field

The invention belongs to the technical field of food processing, and particularly relates to an efficient preparation method of a modified starch-lipid binary compound.

Background

Starch-lipid complexes are mainly supramolecular helical structures formed by self-assembly of amylose and lipid during thermal processing, and are commonly found in processed starch foods. Starch-lipid complexes are of great interest for their unique functional and nutritional health properties, such as reduced starch stiffness, delayed starch retrogradation, improved gelling properties, and reduced starch digestibility and superior fermentation properties. The amount of starch-lipid complex formation and structural stability are influenced by a number of factors, including mainly the starch source, lipid structure and reaction conditions. Among other things, the alkyl chain length, unsaturation, and solubility of lipids can affect the structural and functional properties of starch-lipid complexes. Studies have shown that fatty acids and monoglycerides, etc. can form amylose-lipid complexes of a single helical structure with conventional starch. In the case of diglycerides or triglycerides, however, complexes with conventional starches cannot be formed. In addition, the poor water solubility of fatty acid and monoglyceride results in low complexing efficiency of conventional starch and monoglyceride, thereby limiting the preparation and application of related complexes. Patent application CN110372917A is a method for efficiently preparing starch-lipid complex, which utilizes the emulsifying activity of exogenous additive (β -lactoglobulin) to increase the solubility and dispersibility of lipid in water, thereby obtaining ternary complex, but patent application CN110372917A can only prepare the complex of conventional starch and fatty acid or monoglyceride, but not the complex of starch and diglyceride, by adding exogenous additive (β -lactoglobulin). In addition, because of the high cost of β -lactoglobulin and the limited improvement in efficiency of the long chain fatty acid and starch complexation, the search for new methods to improve the starch and lipid complexation is imminent. How to promote the complex interaction of starch and lipid to form a complex which better meets the requirements on food quality and human nutrition and health is a key problem to be solved urgently in food processing and dietary nutrition regulation.

The conventional starch has certain defects such as cold water insolubility, poor emulsifying capacity and the like. Therefore, there is a need to change the hydrophilic character of conventional starches by chemical modification techniques. For example, the octenyl succinic anhydride is used for esterification reaction with starch to prepare the octenyl succinic acid starch ester, which contains hydrophilic and hydrophobic groups, thereby having excellent emulsifying capacity. Therefore, in the patent of the invention, the conventional starch is modified to improve the emulsifying capacity of a starch molecular chain, so as to promote the efficient compounding of the starch molecular chain and lipid (long-chain fatty acid and diglyceride) to prepare a binary compound, in particular to promote the efficient preparation of a compound of starch octenyl succinate and diglyceride. The method realizes the breakthrough of the preparation technology of the starch-diglyceride compound in food processing, can prepare the starch-lipid compound with specific physicochemical property and nutritional function, has higher efficiency and better quality, and is more beneficial to the improvement of food quality and the adjustment and improvement of human nutritional health.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for compounding and interacting conventional starch and long-chain fatty acid or diglyceride to further efficiently prepare a binary compound, in particular to an efficient preparation method of the compound of the conventional starch and diglyceride.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a high-efficiency preparation method of a modified starch-lipid binary compound comprises the following steps

(1) Preparing conventional corn starch into 10 wt% starch milk by using ionic liquid composite liquid; then, adjusting the pH value of the system to be alkalescent; at room temperature, dropwise adding octenyl succinic anhydride into the starch milk to perform esterification modification, keeping the pH value of the reaction system to be alkalescent, and continuously stirring; after the reaction is finished, adjusting the pH value of the system to be weakly acidic; then centrifuging, washing and drying to obtain octenyl succinic acid starch ester;

(2) adding the octenyl succinic anhydride modified starch obtained in the step (1) into deionized water, stirring to prepare a suspension of 7-20 wt%, then adding lipid, wherein the mass ratio of the lipid to the modified starch is 1: 10-200, and fully and uniformly stirring to obtain a modified starch-lipid suspension;

(3) and (3) heating the modified starch-lipid suspension obtained in the step (2) in a precise temperature-controlled magnetic stirring water bath until the starch is completely gelatinized, cooling to obtain a compound, and freeze-drying and grinding to obtain the binary compound of the octenyl succinic anhydride modified starch and the lipid.

Preferably, in the step (1), the corn starch is blended into 10 wt% of starch milk by using the prepared ionic liquid composite liquid; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; respectively weighing octenyl succinic anhydride with the mass of 1-9% of the dry basis of the starch, and adding starch milk dropwise within 2.5h at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

Preferably, the ionic liquid composite liquid is prepared by mixing 1-ethyl-3-methylimidazolium acetate ionic liquid and water according to the mass ratio of 2: 8.

Preferably, the starch octenyl succinate in the step (2) is added into deionized water, premixed for 3min, and stirred at the speed of 200rpm to prepare a starch suspension with the weight percent of 8; then adding lipid, wherein the mass ratio of the lipid to the modified starch is 1:200, 1:40, 1:20 and 1:10 on a dry basis, and stirring for 2min at the speed of 260 rpm.

Preferably, the lipid is a long chain fatty acid or glyceride.

Preferably, the long-chain fatty acid is palmitic acid and the glyceride is monopalmitin or dipalmitin.

Preferably, the processing and preparation method in the step (3) comprises the following steps: preheating and uniformly mixing, namely preheating and stirring the modified starch-lipid suspension for 2min at 50 ℃ by using a precise temperature control system, wherein the stirring speed is 200 rpm; heating up to 100 ℃ at a heating rate of 25 ℃/min, carrying out composite reaction for 1h, and stirring at a speed of 260 rpm; thirdly, a cooling forming stage, cooling the temperature to 25 ℃ at a cooling rate of 10 ℃/min, and stirring at a speed of 100 rpm; and fourthly, in the stage of sample processing, quickly placing the obtained pasty sample of the modified starch-lipid compound in liquid nitrogen for cooling for 5min, after freeze drying for 24h, grinding for 10min (the rotor specification is 6x phi 0.9cm) by using a high-flux liquid nitrogen freeze grinding instrument under the condition of 10cps of rotating speed, and sieving by using a 100-mesh sieve to obtain the binary compound of the octenyl succinic anhydride modified starch and the lipid.

After potato starch, wheat starch, rice starch and the like of different plant sources are treated by a modification technology, the binary compound prepared by the method is mixed with fatty acids with different chain lengths, such as lauric acid, myristic acid and stearic acid, and corresponding lipids, such as monoglyceride and diglyceride, to obtain similar results.

According to the method for efficiently preparing the starch-lipid compound by modifying the starch through the octenyl succinic anhydride, the emulsifying capacity of the starch is improved by utilizing the octenyl succinic acid group on the modified starch molecular chain, so that the key scientific and technical problem that the composite reaction of the starch and the lipid is influenced by poor dispersibility of fatty acid or diglyceride in water is solved under the condition of not adding any exogenous substances, the interaction of amylose and the lipid, particularly long-chain fatty acid or diglyceride, is greatly improved, the quantity formation and the structural stability of the compound are further remarkably improved, and the binary compound of the octenyl succinic acid starch ester and the dipalmitin is efficiently prepared for the first time.

Compared with the traditional method, the invention has the following advantages and effects:

the invention provides an efficient preparation method of a modified starch-lipid binary compound, which is characterized in that the emulsifying capacity of conventional starch is improved by introducing octenyl succinic anhydride groups through chemical modification of the conventional starch. The modified starch and fatty acid or glyceride are efficiently reacted to prepare the compound of starch-long chain fatty acid and starch-diglyceride through a preheating and uniformly mixing stage, a heating reaction stage, a cooling formation stage and a sample treatment stage under the condition of not adding any exogenous substances. Compared with the product prepared by the traditional process and the preparation method, the compound prepared by the method has an excellent heat stability structure and good emulsifying capacity, overcomes the difficulties that the conventional starch and long-chain fatty acid have low compound efficiency and cannot be compounded and interacted with diglyceride, efficiently prepares the modified starch-diglyceride binary compound with specific physicochemical properties and nutritional functions for the first time, realizes the breakthrough of the traditional preparation method, has higher efficiency and better quality, provides a new insight and technical method for understanding the interaction between starch and lipid, and is more beneficial to the improvement of food quality and the adjustment and improvement of human nutrition and health.

Drawings

FIG. 1(A/B/C) shows X-ray diffraction patterns of examples 1 to 9 and comparative examples 1 to 3, respectively.

FIG. 2(A/B/C) is a Fourier transform infrared spectrum of examples 1 to 9 and comparative examples 1 to 3, respectively.

FIG. 3(A/B/C) is a graph showing confocal Raman spectra of examples 1 to 9 and comparative examples 1 to 3.

FIG. 4 shows confocal laser scanning dye images of examples 1 to 9 and comparative examples 1 to 3.

Detailed Description

The present invention will be further described in more detail by describing exemplary preferred embodiments of the present disclosure in more detail below. While exemplary optimized embodiments of the present disclosure are shown in the specification, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art, and will fully convey the concept and concept of the invention to those skilled in the art.

Example 1

(1) Blending conventional corn starch into 10 wt% of starch milk by using prepared ionic liquid composite liquid; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; octenyl succinic anhydride with the mass of 1 percent of the dry mass of the starch is weighed and is added into the system drop by drop within 2.5 hours at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

(2) Premixing starch octenyl succinate and deionized water for 3min at a stirring speed of 200rpm to prepare 8 wt% starch suspension; and then adding lipid according to the mass ratio of the lipid to the modified starch dry base of 1:20, stirring for 2min at the speed of 260rpm, wherein the long-chain fatty acid is selected as palmitic acid.

(3) The processing and preparation method comprises the following steps: preheating and uniformly mixing, namely preheating and stirring the modified starch-lipid suspension for 2min at 50 ℃ by using a precise temperature control system, wherein the stirring speed is 200 rpm; heating up to 100 ℃ at a heating rate of 25 ℃/min, carrying out composite reaction for 1h, and stirring at a speed of 260 rpm; thirdly, a cooling forming stage, cooling the temperature to 25 ℃ at a cooling rate of 10 ℃/min, and stirring at a speed of 100 rpm; and fourthly, in the stage of sample processing, quickly placing the obtained pasty sample of the modified starch-lipid compound in liquid nitrogen for cooling for 5min, after freeze drying for 24h, grinding for 10min (the rotor specification is 6x phi 0.9cm) by using a high-flux liquid nitrogen freeze grinding instrument under the condition of 10cps of rotating speed, and sieving by using a 100-mesh sieve to obtain the binary compound of the octenyl succinic anhydride modified starch and the palmitic acid.

Example 2

(1) Blending conventional corn starch into 10 wt% of starch milk by using prepared ionic liquid composite liquid; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; octenyl succinic anhydride with the mass of 3 percent of the dry mass of the starch is weighed and is added into the system drop by drop within 2.5 hours at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

(2) The kind and method of preparing modified starch suspension and its added lipid by premixing are the same as those of example 1.

(3) The processing and preparation method is the same as that of example 1.

Example 3

(1) Blending conventional corn starch into 10 wt% of starch milk by using prepared ionic liquid composite liquid; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; octenyl succinic anhydride with the mass of 9 percent of the dry mass of the starch is weighed and is added into the system drop by drop within 2.5 hours at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

(2) The kind and method of preparing modified starch suspension and its added lipid by premixing are the same as those of example 1.

(3) The processing and preparation method is the same as that of example 1.

Example 4

(1) Blending conventional corn starch into 10 wt% of starch milk by using prepared ionic liquid composite liquid; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; octenyl succinic anhydride with the mass of 1 percent of the dry mass of the starch is weighed and is added into the system drop by drop within 2.5 hours at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

(2) Premixing starch octenyl succinate and deionized water for 3min at a stirring speed of 200rpm to prepare 8 wt% starch suspension; and then adding lipid according to the mass ratio of the lipid to the modified starch dry basis of 1:20, stirring for 2min at the speed of 260rpm, wherein the lipid is selected to be the monopalmitin.

(3) The processing and preparation method comprises the following steps: preheating and uniformly mixing, namely preheating and stirring the modified starch-lipid suspension for 2min at 50 ℃ by using a precise temperature control system, wherein the stirring speed is 200 rpm; heating up to 100 ℃ at a heating rate of 25 ℃/min, carrying out composite reaction for 1h, and stirring at a speed of 260 rpm; thirdly, a cooling forming stage, cooling the temperature to 25 ℃ at a cooling rate of 10 ℃/min, and stirring at a speed of 100 rpm; and fourthly, in the stage of sample processing, quickly placing the obtained pasty sample of the modified starch-lipid compound in liquid nitrogen for cooling for 5min, after freeze drying for 24h, grinding for 10min (the rotor specification is 6x phi 0.9cm) by using a high-flux liquid nitrogen freeze grinding instrument under the condition of 10cps of rotating speed, and sieving by using a 100-mesh sieve to obtain the binary compound of the octenyl succinic anhydride modified starch and the monopalmitin.

Example 5

(1) Blending conventional corn starch into 10 wt% of starch milk by using prepared ionic liquid composite liquid; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; octenyl succinic anhydride with the mass of 3 percent of the dry mass of the starch is weighed and is added into the system drop by drop within 2.5 hours at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

(2) The kind and method of preparing modified starch suspension and its added lipid by premixing are the same as those of example 4.

(3) The processing and preparation method is the same as that of example 4.

Example 6

(1) Blending conventional corn starch into 10 wt% of starch milk by using prepared ionic liquid composite liquid; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; octenyl succinic anhydride with the mass of 9 percent of the dry mass of the starch is weighed and is added into the system drop by drop within 2.5 hours at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

(2) The kind and method of preparing modified starch suspension and its added lipid by premixing are the same as those of example 4.

(3) The processing and preparation method is the same as that of example 4.

Example 7

(1) Blending conventional corn starch into 10 wt% of starch milk by using prepared ionic liquid composite liquid; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; octenyl succinic anhydride with the mass of 1 percent of the dry mass of the starch is weighed and is added into the system drop by drop within 2.5 hours at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

(2) Premixing starch octenyl succinate and deionized water for 3min at a stirring speed of 200rpm to prepare 8 wt% starch suspension; and then adding lipid according to the mass ratio of the lipid to the modified starch dry basis of 1:20, stirring for 2min at the speed of 260rpm, wherein the lipid is selected to be the dipalmitoyl glyceride.

(3) The processing and preparation method comprises the following steps: preheating and uniformly mixing, namely preheating and stirring the modified starch-lipid suspension for 2min at 50 ℃ by using a precise temperature control system, wherein the stirring speed is 200 rpm; heating up to 100 ℃ at a heating rate of 25 ℃/min, carrying out composite reaction for 1h, and stirring at a speed of 260 rpm; thirdly, a cooling forming stage, cooling the temperature to 25 ℃ at a cooling rate of 10 ℃/min, and stirring at a speed of 100 rpm; and fourthly, in the stage of sample processing, quickly placing the obtained pasty sample of the modified starch-lipid compound in liquid nitrogen for cooling for 5min, after freeze drying for 24h, grinding for 10min (the rotor specification is 6x phi 0.9cm) by using a high-flux liquid nitrogen freeze grinding instrument under the condition of 10cps of rotating speed, and sieving by using a 100-mesh sieve to obtain the binary compound of the octenyl succinic anhydride modified starch and the dipalmitin.

Example 8

(1) Blending conventional corn starch into 10 wt% of starch milk by using prepared ionic liquid composite liquid; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; octenyl succinic anhydride with the mass of 3 percent of the dry mass of the starch is weighed and is added into the system drop by drop within 2.5 hours at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

(2) The kind and method of preparing modified starch suspension and its added lipid by premixing are the same as those of example 7.

(3) The preparation method is the same as that of example 7.

Example 9

(1) Blending conventional corn starch into 10 wt% of starch milk by using prepared ionic liquid composite liquid; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; octenyl succinic anhydride with the mass of 9 percent of the dry mass of the starch is weighed and is added into the system drop by drop within 2.5 hours at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

(2) The kind and method of preparing modified starch suspension and its added lipid by premixing are the same as those of example 7.

(3) The preparation method is the same as that of example 7.

Comparative example 1

(1) Premixing conventional corn starch and deionized water for 3min at a stirring speed of 200rpm to prepare a starch suspension with the weight percent of 8; and then adding lipid according to the mass ratio of 1:20 of the lipid to the conventional starch dry basis, stirring for 2min at the speed of 260rpm, and selecting long-chain fatty acid as palmitic acid as the lipid.

(2) The preparation method is the same as that of example 1

Comparative example 2

(1) Premixing conventional corn starch and deionized water for 3min at a stirring speed of 200rpm to prepare a starch suspension with the weight percent of 8; and then adding lipid according to the mass ratio of 1:20 of the lipid to the conventional starch dry basis, stirring for 2min at the speed of 260rpm, wherein the lipid is selected to be the monopalmitin.

(2) The processing and preparation method is the same as that of example 4.

Comparative example 3

(1) Premixing conventional corn starch and deionized water for 3min at a stirring speed of 200rpm to prepare a starch suspension with the weight percent of 8; and then adding lipid according to the mass ratio of 1:20 of the lipid to the conventional starch dry basis, stirring for 2min at the speed of 260rpm, wherein the lipid is selected to be the dipalmitoyl glyceride.

(2) The preparation method is the same as that of example 7.

The results of the relevant tests of all examples and comparative examples prepared by the process of the invention are:

(1) the Degree of Substitution (DS) of the octenyl succinic anhydride modified starch was determined for different percentages (1%, 3% and 9%).

Weighing 2.0g of sample, placing in a 250mL beaker, wetting with 10mL of isopropanol, stirring for 10min, adding 15mL of 2.5mol/L hydrochloric acid-isopropanol solution, magnetically stirring for 30min, then adding 50mL of 90% isopropanol solution, and continuing to stir for 10 min. The sample was transferred to a buchner funnel and washed with 90% isopropanol to Cl-free^-(test with 0.1mol/L silver nitrate). And then transferring the sample into a 500mL beaker, adding deionized water to 300mL, carrying out boiling water bath for 20min, adding 2 drops of phenolphthalein reagent, and titrating the mixture to pink by using 0.1mol/L sodium hydroxide solution while the mixture is hot, wherein the mixture does not change color within 30 s. Calculated according to the following formula: the degree of substitution is 0.1624 × N/(1-0.21 × N), N representing the amount of material (mmol) consumed per 0.1mol/L of sodium hydroxide standard solution.

(2) And (4) measuring the emulsifying capacity of the modified starch.

The suspension of starch sample (1.5%, w/w) was heated in a boiling water bath and stirred for 20 min. To the starch suspension was added soybean oil (5% of the mass of the starch suspension) in a high speed homogenizer (Ultra-turrax t18) to prepare an oil-in-water (O/W) emulsion. At room temperature, 12000rpm total 4 times, single homogenization time is 1.5 min. Then, 50. mu.L of the emulsion was uniformly mixed with 5mL of 0.1% sodium lauryl sulfateAnd combining to form a fine emulsion. Blank with 0.1% sodium dodecyl sulfate and absorbance at 500nm (A)₀) The emulsifying activity was measured. After the sample emulsion was left to stand for 20min, the absorbance (A) was measured again at 500nm₂₀). The emulsion stability was calculated according to the following formula: emulsion stability (min) ═ 20 × a₀/(A₀-A₂₀)。

The results are shown in table 1, as the percent addition of octenyl succinic anhydride is increased (1% -9%), the substitution degree of octenyl succinic anhydride groups in the modified starch is gradually increased from 0.0071 to 0.0489, and the emulsifying activity and emulsifying capacity of the modified starch are up to 2.09 and 1213.5min, which are remarkably improved compared with the conventional starch.

TABLE 1 degree of substitution, emulsifying Activity and emulsifying Capacity of modified starches

Note: the data in the table are mean ± standard deviation; the letters of the suffix are identical and represent no significant difference, and different letters represent significant differences (p < 0.05); "/" indicates no data detected.

(3) And (4) determining the composite index of the composite sample.

A50 mL centrifuge tube was weighed with starch-lipid complex (0.4g) and distilled water was added to a total weight of 5.0 g. After vortexing, the homogeneous suspension was heated in a boiling water bath with a magnetic stirring speed of 200rpm until the starch was completely gelatinized. After cooling to room temperature, 25mL of distilled water was added and vortexed for 2min before centrifugation (3000g, 15 min). mu.L of the supernatant was transferred to a test tube, and 15mL of distilled water and 2mL of iodine solution (2.0% KI and 1.3% I) were added₂In distilled water). UV absorbance was measured at 690 nm. Conventional corn starch treated in the above manner served as a control. The composite index is calculated according to the following formula: composite index (%). 100 · (absorbance)_ControlAbsorbance of_{Starch-lipids}) Absorbance_Control。

The above results are shown in table 2, and in the comparative example, after the conventional starch is complexed with palmitic acid, monopalmitin and dipalmitin, respectively, the complexing interaction with monopalmitin (comparative example 2) is stronger than that with palmitic acid (comparative example 1), and substantially no complex is generated with dipalmitin (comparative example 3). After the conventional starch is modified by octenyl succinic anhydride, the composite effect of the modified starch and various lipids is enhanced. Compared with comparative example 1 and comparative example 3, the composite interaction of examples 1-3 and examples 7-9 is obviously enhanced, the composite index is obviously increased, and the composite index is increased from 21.6% or 8.6% of the composite index of comparative example 1 or comparative example 3 to 93.3% or 93.2%. And with the increase of the modification degree (substitution degree) of the octenyl succinic anhydride, the improvement effect of the composite index of the modified starch and the long-chain fatty acid or glyceride is better, and particularly the composite interaction efficiency of the modified starch and the dipalmitin is better (examples 7-9).

TABLE 2 composite index (%)

Note: the data in the table are mean ± standard deviation; the letters of the suffix are identical, meaning no significant difference, and different letters are significant differences (p < 0.05).

(4) The crystal structures of the conventional starch-lipid and modified starch-lipid complexes were examined using an X-ray diffractometer (D8Advance) from Bruker, Germany (see FIG. 1). The results of the measurements show that binary compounds prepared from octenyl succinic acid starch ester, examples 1 to 3, examples 4 to 6 and examples 7 to 9, exhibited stronger diffraction peaks (12.9 ° and 19.8 °) for V-type crystal characteristics, compared to comparative binary compounds prepared from conventional starch, indicating that the examples prepared from modified starch were composed of V-type crystal compounds having a stable structure and a greater number, and the structure and number of binary compounds were gradually stabilized and increased as the emulsifying activity of octenyl succinic anhydride modified starch was increased.

(5) The short-range molecular order structure of conventional starch-lipid and modified starch-lipid complexes was examined using a Fourier transform infrared spectrometer (IS50) from Bruker, Germany (see FIG. 2). The results of the measurements show that binary compounds prepared from octenyl succinic anhydride starch ester, examples 1-3, examples 4-6 and examples 7-9, exhibit better short-range molecular order than binary compounds prepared from conventional starch, comparative examples 1-3, and the short-range molecular order of binary compounds is significantly improved as the degree of substitution of octenyl succinic anhydride modified starch increases.

(6) The short-range molecular order structure of conventional starch-lipid and modified starch-lipid complexes was analyzed using a laser confocal raman imaging spectrometer (Renishaw inviia) from Renishaw corporation, uk (see figure 3). The results of the measurements show that binary compounds prepared from octenyl succinic anhydride starch ester, examples 1-3, examples 4-6 and examples 7-9, exhibit better short-range molecular order than binary compounds prepared from conventional starch, comparative examples 1-3, and the short-range molecular order of binary compounds is significantly improved as the degree of substitution of octenyl succinic anhydride modified starch increases.

(7) The actual sample morphology of the conventional starch-lipid and modified starch-lipid complexes was analyzed using a laser scanning confocal microscope (TCSSP5) from Leica, germany (see fig. 4). The results of the measurements show that (starch structure showing green fluorescence, lipid structure showing red fluorescence, complex structure showing yellow fluorescence) the actual morphology of binary complexes prepared with conventional starch, comparative examples 1-3, showed poor agglomerates or mixtures (green fluorescence showing), although the comparative example 2 had a rod-like structure of the complex, but in relatively small amounts. While binary complexes prepared from starch octenylsuccinate examples 1-3, 4-6 and 7-9 exhibited a greater number of true rod-like morphologies (yellow fluorescent rod-like structures) of the complexes, and more binary complexes appeared in the samples of examples 3, 6 and 9, which was first prepared by the method of the present invention and photographed with respect to the true morphology of the binary complexes of starch octenylsuccinate and lipids.

(8) Analysis of conventional starch-lipid and modified starch-lipid complexes Using a high sensitivity differential scanning calorimeter (200F3) from Netzsch, GermanyThermodynamic properties of matter. The above results are shown in Table 3, and the analysis of the test results shows that binary complex of starch octenylsuccinate and lipid has better melting temperature (T)_pⅡ) And greater enthalpy values (Δ H). Examples 1-3, examples 4-6 and examples 7-9 possess superior thermal stability and a more ordered crystal structure compared to composites prepared from conventional starch (comparative examples 1-3).

Example 10

(1) Blending conventional corn starch into 10 wt% of starch milk by using prepared ionic liquid composite liquid; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; octenyl succinic anhydride with the mass of 1 percent of the dry mass of the starch is weighed and is added into the system drop by drop within 2.5 hours at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

(2) Premixing starch octenyl succinate and deionized water for 3min at a stirring speed of 200rpm to prepare 7 wt% of starch suspension; and then adding lipid according to the mass ratio of the lipid to the modified starch dry basis of 1:10, stirring for 2min at the speed of 260rpm, wherein the lipid is selected to be the dipalmitoyl glyceride.

(3) The processing and preparation method is the same as that of example 4.

Example 11

(1) Blending conventional corn starch into 10 wt% of starch milk by using prepared ionic liquid composite liquid; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; octenyl succinic anhydride with the mass of 1 percent of the dry mass of the starch is weighed and is added into the system drop by drop within 2.5 hours at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

(2) Premixing starch octenyl succinate and deionized water for 3min at a stirring speed of 200rpm to prepare 20 wt% starch suspension; and then adding lipid according to the mass ratio of the lipid to the modified starch dry basis of 1:40, stirring for 2min at the speed of 260rpm, wherein the lipid is selected to be the dipalmitoyl glyceride.

(3) The processing and preparation method is the same as that of example 4.

Example 12

(1) Blending conventional corn starch into 10 wt% of starch milk by using prepared ionic liquid composite liquid; then adding 0.5M sodium hydroxide solution to adjust the pH value of the system to 8.0-8.5; octenyl succinic anhydride with the mass of 1 percent of the dry mass of the starch is weighed and is added into the system drop by drop within 2.5 hours at the temperature of 25 ℃ to modify the starch; the modification reaction lasts for 5h, and the stirring speed is 200 rpm; after the reaction is finished, adjusting the pH value of the system to 6.0; alternately centrifuging and washing with deionized water and 70% ethanol for 3 times, respectively, centrifuging at a centrifugal force of 5000g for 10 min; drying for 12h at 40 ℃ in a vacuum drying oven to obtain the octenyl succinic acid starch ester.

(2) Premixing starch octenyl succinate and deionized water for 3min at a stirring speed of 200rpm to prepare 8 wt% starch suspension; and then adding lipid according to the mass ratio of the lipid to the modified starch dry basis of 1:200, stirring for 2min at the speed of 260rpm, wherein the lipid is selected to be the dipalmitoyl glyceride.

(3) The processing and preparation method is the same as that of example 4.

The binary compound obtained in the three embodiments has better indexes than those of the binary compound prepared by compounding common starch. The compounding method of the invention is simple and easy to operate.

By combining the test data and result analysis, the invention provides an efficient preparation method of a modified starch-lipid binary compound. Compared with the defects and shortcomings of the traditional method for preparing the compound, the method breaks through the technical barrier of the compound interaction between the starch and the diglyceride under the condition of no exogenous additive, and the V-shaped crystal structure, the molecular order and the thermal stability of the obtained modified starch-lipid compound are superior to those of the conventional starch-lipid compound, so that the compound efficiency between the starch and the lipid is greatly improved, and the method has important significance for improving the quality of food in food processing and improving the nutritional health of human bodies.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

All changes in structure without creative work from the conception of the invention fall into the protection scope of the invention.

TABLE 3 thermodynamic Properties of octenyl succinic anhydride modified starch and lipid binary complexes

Note: the data in the table are mean ± standard deviation; the letters of the suffix are identical and represent no significant difference, and different letters represent significant differences (p < 0.05); "/" indicates no data detected.