A method for preparing micro-nano starch particle-based Pickering emulsion with micro-heat-induced interfacial chain response

Abstract

The invention discloses a method for preparing a micro-nano starch particle-based Pickering emulsion with micro-thermal induced interface response, comprising the following steps: (1) dispersing 0.2-1 parts by mass of micro-nano starch particles in 59 parts by mass of an aqueous phase, and homogenizing to obtain a micro-nano starch particle suspension; (2) subjecting the micro-nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; (3) adding 40 parts by mass of an oil phase to the ultrasonic suspension, and then homogenizing to obtain a micro-nano starch particle-based Pickering emulsion; (4) subjecting the micro-nano starch particle-based Pickering emulsion to thermal induction, and then cooling in an ice bath to obtain a micro-nano starch-based Pickering emulsion with micro-thermal induced interface chain response. The micro-thermal induced emulsion of the invention has extremely high stability and a storage time of more than 1 year.

Description

Technical Field

[0001] The invention relates to the technical field of Pickering emulsion preparation, in particular to a method for preparing a micro-nano starch particle-based Pickering emulsion with micro-heat-induced interface chain response. Background Art

[0002] Pickering emulsion is a new type of emulsion that uses solid particles to replace traditional organic surfactants to stabilize the emulsion system. Since no organic surfactants are added, Pickering emulsion has higher safety and biocompatibility, and is suitable for most food and cosmetic raw materials.

[0003] Starch is a common high-molecular carbohydrate, a polysaccharide formed by the polymerization of glucose molecules, with large quantity, abundant source and low price. However, due to its large particle size (above 10μm) and strong hydrophilicity, ordinary starch cannot form stable interface particles at the oil-water interface. Therefore, it is necessary to modify the starch to enhance its hydrophobicity to stabilize the oil-water interface. However, common modification methods usually contain inedible ingredients, such as octenyl succinate, etc., which is unreasonable when used in food. Therefore, the present invention gelatinizes and alcohol-precipitates ordinary starch to prepare edible and safe nano starch particles (Nano Starch Particle, NSP) as a stabilizer for stabilizing the oil-water interface.

[0004] The existing preparation process of micro-nano starch-based Pickering emulsion is to first gelatinize and precipitate starch particles, then obtain smaller nanoparticles by shearing, and then mix the micro-nano starch with oil and water and homogenize to obtain the Pickering emulsion. Under this condition, the micro-nano starch particles in the emulsion are distributed in a granular form and adsorbed on the oil-water interface. The emulsion obtained by these steps usually has poor stability and a short storage period. Summary of the invention

[0005] In order to solve the problem of poor stability and short storage period of micro-nano starch-based Pickering emulsion, the present invention provides a method for preparing a micro-nano starch particle-based Pickering emulsion with micro-thermal induced interface chain response, wherein the micro-nano starch obtained by gelatinization and alcohol precipitation shearing of ordinary starch is first mixed with oil and water and homogenized to obtain a preliminary Pickering emulsion, and then the emulsion is subjected to micro-thermal induction on the basis of the above steps to induce the starch chain fixed in the interface to unfold, so that the starch chain extends into the aqueous phase, and then quickly cooled in an ice bath to form a network structure. The emulsion after micro-thermal induction is extremely stable and has a long storage period. The micro-nano starch particles have the characteristics of high stability, high safety and abundant sources, which can be used to stabilize the Pickering emulsion, and the prepared emulsion obtains ultra-stability through the heat-induced interface chain response technology, which provides a very promising alternative for the delivery of functional nutrients in related industries such as functional foods.

[0006] Specifically, the present invention adopts the following technical solution: a method for preparing a micro-nano starch particle-based Pickering emulsion with micro-heat-induced interfacial response, comprising the following steps:

[0007] (1) dispersing 0.2-1 parts by weight of nano starch particles in 59 parts by weight of an aqueous phase and homogenizing the mixture to obtain a nano starch particle suspension;

[0008] (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension;

[0009] (3) adding 40 parts by weight of the oil phase to the ultrasonic suspension, followed by homogenization to obtain a Pickering emulsion based on micro-nano starch particles; the emulsion obtained by ultra-high-speed homogenization of the water phase, the oil phase and the micro-nano starch particles in the present invention;

[0010] (4) The nano-starch particle-based Pickering emulsion is thermally induced and then cooled in an ice bath to obtain a nano-starch-based Pickering emulsion with a micro-thermally induced interfacial chain response.

[0011] The present invention conducts water bath heating to induce the starch chains fixed in the interface to unfold. At this time, the water molecules will form hydrogen bonds with the hydroxyl groups (-OH) in the starch molecules, causing the starch chains to swell. In the presence of continuous phase water, the micro-nano starch molecules in the interface will gradually unfold toward the water phase. For amylose, hydration relaxes its chain structure; for amylopectin, hydration makes the chain segments in its branched structure looser. After ice bath cooling, the starch chains will interact with each other again and recrystallize, a process similar to regeneration. In the process of re-interaction, some of the unfolded starch chains will re-aggregate into a more ordered structure, forming a network-like region, and further forming an ultra-stable Pickering emulsion. And due to the above principle, the amount of micro-nano starch used in the present invention is much less than that of the prior art, which can greatly save costs.

[0012] Furthermore, the nano starch particles in step (1) are derived from one or more of corn, wheat, potato and potatoes.

[0013] Furthermore, the aqueous phase in step (1) is deionized water.

[0014] Furthermore, in step (1), the homogenization speed is 15000-18000 rpm, and the time is 5-10 min.

[0015] Furthermore, the ultrasonic treatment time in step (2) is 10 minutes.

[0016] Furthermore, the oil phase in step (3) is one of sesame oil, soybean oil, corn oil, olive oil and rapeseed oil.

[0017] Furthermore, in step (3), the homogenization speed is 15000-20000 rpm, and the homogenization time is 1-10 min.

[0018] Furthermore, the thermal induction in step (4) is carried out by water bath heating for 20 to 50 minutes at a temperature of 40 to 90°C.

[0019] Furthermore, the ice bath cooling time in step (4) is greater than or equal to 10 minutes.

[0020] The beneficial effects of the present invention are: extremely high stability, a storage time of more than one year, and a much smaller amount of micro-nano starch than the prior art, which can greatly save costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The process flow chart of preparing the pre-emulsion and the ultra-stable Pickering emulsion of the present invention;

[0022] Figure 2 is the instability index of Examples 1 to 6 of the present invention;

[0023] Figure 3 is the instability index of Example 1 of the present invention and Comparative Examples 1 to 6;

[0024] Figure 4 This is a physical picture of Examples 1 to 6 of the present invention after simulating one year of storage;

[0025] Figure 5 This is a physical picture of Example 1 of the present invention and Comparative Examples 1 to Comparative Examples 6 after simulating one year of storage. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] The present invention is further illustrated by the following examples, which are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0028] As is known in the art, the micro-nano starch particles in the present invention are starch particles with a particle size of less than 1 micron, which can be prepared by gelatinizing and alcohol precipitation of ordinary starch. The homogenizer used in the embodiment of the present application is T18, IKA, Germany.

[0029] Example 1

[0030] like Figure 1 A method for preparing a micro-nano starch particle-based Pickering emulsion with micro-heat-induced interfacial chain response comprises the following steps:

[0031] (1) Disperse 0.2 g corn-based nano starch particles in 59 g deionized water and homogenize to obtain a nano starch particle suspension; the homogenization speed is 15000 rpm and the time is 10 min;

[0032] (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; the ultrasonic treatment time is 10 min;

[0033] (3) Add 40 g of sesame oil to the ultrasonic suspension, followed by homogenization to obtain a micro-nano starch particle-based Pickering emulsion; the homogenization speed is 15000 rpm, and the homogenization time is 10 min;

[0034] (4) The nano starch particle-based Pickering emulsion is thermally induced and then ice-cooled to obtain a nano starch-based Pickering emulsion with a micro thermal induced interfacial chain response; the thermal induction is performed by heating in a water bath for 20 min at a temperature of 90°C; and the ice bath cooling time is 20 min.

[0035] like Figure 2 The instability index of Example 1 is a simulated 1-year stability analysis in a centrifugal analyzer (LUMisizer, GmbH, Germany). The sample is irradiated with near-infrared light, and the entire sample can be observed and analyzed from top to bottom at the same time. The centrifugal acceleration method is used to simply test and quantify the separation behavior of the emulsion; the smaller the instability index, the more stable the emulsion. In the test of Example 1, the sample is first inserted into the analytical centrifugal analyzer. The analysis method is to scan once every 30 seconds, a total of 480 scans, and measure at 23°C and 4000rpm for 4 hours to simulate the stability after 1 year. According to the software provided by the instrument, the average instability index is 0.128, showing excellent stability. Figure 4 In the photo of Example 1, the emulsion shows a very uniform and stable state after a simulated storage period of 1 year, indicating that it can be stably stored for more than 1 year. The thermal induction of 20 minutes and 90°C causes the starch chains fixed in the interface to unfold. At this time, the water molecules will form hydrogen bonds with the hydroxyl groups (-OH) in the starch molecules, causing the starch chains to swell. In the presence of continuous phase water, the micro-nano starch molecules in the interface will gradually unfold toward the water phase. After 20 minutes of ice bath cooling, the starch chains will re-interact and recrystallize. In the process of re-interaction, some of the unfolded starch chains will re-aggregate into a more ordered structure, forming a network-like region, further forming an ultra-stable Pickering emulsion. In this embodiment, the 20-minute ice bath cooling time is sufficient to allow the starch chains at 90°C to re-interact and re-crystallize. In some embodiments, a longer ice bath cooling time can also achieve the purpose.

[0036] Example 2

[0037] like Figure 1 A method for preparing a micro-nano starch particle-based Pickering emulsion with micro-heat-induced interfacial chain response comprises the following steps:

[0038] (1) Disperse 0.4 g wheat-based nano starch particles in 59 g deionized water and homogenize to obtain a nano starch particle suspension; the homogenization speed is 16000 rpm and the time is 8 min;

[0039] (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; the ultrasonic treatment time is 10 min;

[0040] (3) Add 40 g soybean oil to the ultrasonic suspension, followed by homogenization to obtain a micro-nano starch particle-based Pickering emulsion; the homogenization speed is 16000 rpm, and the homogenization time is 8 min;

[0041] (4) The nano starch particle-based Pickering emulsion was thermally induced and then ice-cooled to obtain a nano starch-based Pickering emulsion with a micro thermal induced interfacial chain response; the thermal induction was performed by heating in a water bath for 26 min at a temperature of 80°C; the ice bath cooling time was 18 min.

[0042] like Figure 2 The instability index of Example 2 is a simulated 1-year stability analysis in a centrifugal analyzer (LUMisizer, GmbH, Germany). The sample is irradiated with near-infrared light, and the entire sample can be observed and analyzed from top to bottom at the same time. The centrifugal acceleration method is used to simply test and quantify the separation behavior of the emulsion; the smaller the instability index, the more stable the emulsion. In the test of Example 2, the sample is first inserted into the analytical centrifugal analyzer. The analysis method is to scan once every 30 seconds, a total of 480 scans, and measure at 23°C and 4000rpm for 4 hours to simulate the stability after 1 year. According to the software provided by the instrument, the average instability index is 0.134, showing excellent stability. Figure 4 In the photo of Example 2, the emulsion is in a very uniform and stable state after a simulated storage period of 1 year, indicating that it can be stably stored for more than 1 year. The thermal induction of 26 minutes and 80°C causes the starch chains fixed in the interface to unfold, and the water molecules will form hydrogen bonds with the hydroxyl groups (-OH) in the starch molecules at this time, causing the starch chains to swell. In the presence of continuous phase water, the micro-nano starch molecules in the interface will gradually unfold toward the water phase. After 18 minutes of ice bath cooling, the starch chains will re-interact and recrystallize. In the process of re-interaction, some of the unfolded starch chains will re-aggregate into a more ordered structure, forming a network-like region, further forming an ultra-stable Pickering emulsion.

[0043] Example 3

[0044] like Figure 1 A method for preparing a micro-nano starch particle-based Pickering emulsion with micro-heat-induced interfacial chain response comprises the following steps:

[0045] (1) Disperse 0.6 g of potato-based nano starch particles in 59 g of deionized water and homogenize to obtain a nano starch particle suspension; the homogenization speed is 17000 rpm and the time is 6.5 min;

[0046] (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; the ultrasonic treatment time is 10 min;

[0047] (3) Add 40 g corn oil to the ultrasonic suspension, followed by homogenization to obtain a micro-nano starch particle-based Pickering emulsion; the homogenization speed is 17000 rpm, and the homogenization time is 6.5 min;

[0048] (4) The nano starch particle-based Pickering emulsion was thermally induced and then ice-cooled to obtain a nano starch-based Pickering emulsion with a micro thermal induced interfacial chain response; the thermal induction was performed by heating in a water bath for 32 min at a temperature of 70°C; the ice bath cooling time was 16 min.

[0049] like Figure 2 The instability index of Example 3 is a simulated 1-year stability analysis in a centrifugal analyzer (LUMisizer, GmbH, Germany). The sample is irradiated with near-infrared light, and the entire sample can be observed and analyzed from top to bottom at the same time. The centrifugal acceleration method is used to simply test and quantify the separation behavior of the emulsion; the smaller the instability index, the more stable the emulsion. In the test of Example 3, the sample is first inserted into the analytical centrifugal analyzer. The analysis method is to scan once every 30 seconds, a total of 480 scans, and measure at 23°C and 4000rpm for 4 hours to simulate the stability after 1 year. According to the software provided by the instrument, the average instability index is 0.154, showing excellent stability. Figure 4 In the photo of Example 3, the emulsion is in a very uniform and stable state after a simulated storage period of 1 year, indicating that it can be stably stored for more than 1 year. The thermal induction of 32 minutes and 70°C causes the starch chains fixed in the interface to unfold, and the water molecules will form hydrogen bonds with the hydroxyl groups (-OH) in the starch molecules at this time, causing the starch chains to swell. In the presence of continuous phase water, the micro-nano starch molecules in the interface will gradually unfold toward the water phase. After 16 minutes of ice bath cooling, the starch chains will re-interact and recrystallize. In the process of re-interaction, some of the unfolded starch chains will re-aggregate into a more ordered structure, forming a network-like region, further forming an ultra-stable Pickering emulsion.

[0050] Example 4

[0051] like Figure 1 A method for preparing a micro-nano starch particle-based Pickering emulsion with micro-heat-induced interfacial chain response comprises the following steps:

[0052] (1) Disperse 0.8 g of potato-based nano starch particles in 59 g of deionized water and homogenize to obtain a nano starch particle suspension; the homogenization speed is 18000 rpm and the time is 5 min;

[0053] (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; the ultrasonic treatment time is 10 min;

[0054] (3) Add 40 g of olive oil to the ultrasonic suspension, followed by homogenization to obtain a micro-nano starch particle-based Pickering emulsion; the homogenization speed is 18000 rpm, and the homogenization time is 4 min;

[0055] (4) The nano starch particle-based Pickering emulsion was thermally induced and then ice-cooled to obtain a nano starch-based Pickering emulsion with a micro-thermal induced interfacial chain response; the thermal induction was performed by heating in a water bath for 38 min at a temperature of 60°C; the ice bath cooling time was 14 min.

[0056] like Figure 2 The instability index of Example 4 is a simulated 1-year stability analysis in a centrifugal analyzer (LUMisizer, GmbH, Germany). The sample is irradiated with near-infrared light, and the entire sample can be observed and analyzed from top to bottom at the same time. The centrifugal acceleration method is used to simply test and quantify the separation behavior of the emulsion; the smaller the instability index, the more stable the emulsion. In the test of Example 4, the sample is first inserted into the analytical centrifugal analyzer. The analysis method is to scan once every 30 seconds, a total of 480 scans, and measure at 23°C and 4000rpm for 4 hours to simulate the stability after 1 year. According to the software provided by the instrument, the average instability index is 0.135, showing excellent stability. Figure 4 In the photo of Example 4, the emulsion showed a very uniform and stable state after a simulated storage period of 1 year, indicating that it can be stably stored for more than 1 year. The thermal induction of 38min and 60℃ causes the starch chains fixed in the interface to unfold, and the water molecules will form hydrogen bonds with the hydroxyl groups (-OH) in the starch molecules at this time, causing the starch chains to swell. In the presence of continuous phase water, the micro-nano starch molecules in the interface will gradually unfold toward the water phase. After 14min of ice bath cooling, the starch chains will re-interact and recrystallize. In the process of re-interaction, some of the unfolded starch chains will re-aggregate into a more ordered structure, forming a network-like region, further forming an ultra-stable Pickering emulsion.

[0057] Example 5

[0058] like Figure 1A method for preparing a micro-nano starch particle-based Pickering emulsion with micro-heat-induced interfacial chain response comprises the following steps:

[0059] (1) Disperse 0.25 g corn and 0.25 g wheat-based nano starch particles in 59 g deionized water and homogenize to obtain a nano starch particle suspension; the homogenization speed is 18000 rpm and the time is 5 min;

[0060] (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; the ultrasonic treatment time is 10 min;

[0061] (3) Add 40 g of olive oil to the ultrasonic suspension, followed by homogenization to obtain a micro-nano starch particle-based Pickering emulsion; the homogenization speed is 19000 rpm, and the homogenization time is 2.5 min;

[0062] (4) The nano starch particle-based Pickering emulsion was thermally induced and then ice-cooled to obtain a nano starch-based Pickering emulsion with a micro thermal induced interfacial chain response; the thermal induction was performed by heating in a water bath for 44 min at a temperature of 50°C; and the ice bath cooling time was 12 min.

[0063] like Figure 2 The instability index of Example 5 is a simulated 1-year stability analysis in a centrifugal analyzer (LUMisizer, GmbH, Germany). The sample is irradiated with near-infrared light, and the entire sample can be observed and analyzed from top to bottom at the same time. The centrifugal acceleration method is used to simply test and quantify the separation behavior of the emulsion; the smaller the instability index, the more stable the emulsion. In the test of Example 5, the sample is first inserted into the analytical centrifugal analyzer. The analysis method is to scan once every 30 seconds, a total of 480 scans, and the measurement is carried out at 23°C and 4000rpm for 4 hours to simulate the stability after 1 year. According to the software provided by the instrument, the average instability index is 0.136, showing excellent stability. Figure 4 In the photo of Example 5, the emulsion is in a very uniform and stable state after a simulated storage period of 1 year, indicating that it can be stably stored for more than 1 year. The thermal induction of 44min and 50℃ causes the starch chains fixed in the interface to unfold, and the water molecules will form hydrogen bonds with the hydroxyl groups (-OH) in the starch molecules at this time, causing the starch chains to swell. In the presence of continuous phase water, the micro-nano starch molecules in the interface will gradually unfold toward the water phase. After 12min of ice bath cooling, the starch chains will re-interact and recrystallize. In the process of re-interaction, some of the unfolded starch chains will re-aggregate into a more ordered structure, forming a network-like region, further forming an ultra-stable Pickering emulsion.

[0064] Example 6

[0065] like Figure 1 A method for preparing a micro-nano starch particle-based Pickering emulsion with micro-heat-induced interfacial chain response comprises the following steps:

[0066] (1) Disperse 0.25 g corn, 0.25 g wheat, 0.25 g potato and 0.25 g potato-based nano starch particles in 59 g deionized water and homogenize to obtain a nano starch particle suspension; the homogenization speed is 18000 rpm and the time is 5 min;

[0067] (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; the ultrasonic treatment time is 10 min;

[0068] (3) adding 40 g rapeseed oil to the ultrasonic suspension, followed by homogenization to obtain a micro-nano starch particle-based Pickering emulsion; the homogenization speed was 20,000 rpm, and the homogenization time was 1 min;

[0069] (4) The nano starch particle-based Pickering emulsion was thermally induced and then ice-cooled to obtain a nano starch-based Pickering emulsion with a micro thermal induced interfacial chain response; the thermal induction was performed by heating in a water bath for 50 min at a temperature of 40°C; and the ice bath cooling time was 10 min.

[0070] like Figure 2 The instability index of Example 6 is a simulated 1-year stability analysis in a centrifugal analyzer (LUMisizer, GmbH, Germany). The sample is irradiated with near-infrared light, and the entire sample can be observed and analyzed from top to bottom at the same time. The centrifugal acceleration method is used to simply test and quantify the separation behavior of the emulsion; the smaller the instability index, the more stable the emulsion. In the test of Example 6, the sample is first inserted into the analytical centrifugal analyzer. The analysis method is to scan once every 30 seconds, a total of 480 scans, and the measurement is carried out at 23°C and 4000rpm for 4 hours to simulate the stability after 1 year. According to the software provided by the instrument, the average instability index is 0.122, showing excellent stability. Figure 4In the photo of Example 6, the emulsion is in a very uniform and stable state after a simulated storage period of 1 year, indicating that it can be stably stored for more than 1 year. The thermal induction of 50min and 40℃ causes the starch chains fixed in the interface to unfold, and the water molecules will form hydrogen bonds with the hydroxyl groups (-OH) in the starch molecules at this time, causing the starch chains to swell. In the presence of continuous phase water, the micro-nano starch molecules in the interface will gradually unfold toward the water phase. After 10min of ice bath cooling, the starch chains will re-interact and recrystallize. In the process of re-interaction, some of the unfolded starch chains will re-aggregate into a more ordered structure, forming a network-like region, further forming an ultra-stable Pickering emulsion.

[0071] Comparative Example 1

[0072] This comparative example is substantially the same as Example 1, except that the thermally induced temperature is higher.

[0073] (1) Disperse 0.2 g corn nano starch particles in 59 g deionized water and homogenize to obtain a nano starch particle suspension; the homogenization speed is 15000 rpm and the time is 10 min;

[0074] (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; the ultrasonic treatment time is 10 min;

[0075] (3) Add 40 g of sesame oil to the ultrasonic suspension, followed by homogenization to obtain a micro-nano starch particle-based Pickering emulsion; the homogenization speed is 15000 rpm, and the homogenization time is 10 min;

[0076] (4) The nano starch particle-based Pickering emulsion was thermally induced and then ice-cooled to obtain a nano starch-based Pickering emulsion with a micro thermal induced interfacial chain response; the thermal induction was performed by heating in a water bath for 20 min at a temperature of 100°C; and the ice bath cooling time was 20 min.

[0077] like Figure 3 The instability index of comparative example 1 is simulated by a one-year stability analysis in a centrifugal analyzer (LUMisizer, GmbH, Germany). The sample is irradiated with near-infrared light, and the entire sample can be observed and analyzed from top to bottom at the same time. The centrifugal acceleration method is used to simply test and quantify the separation behavior of the emulsion; the larger the instability index, the more unstable the emulsion. In the test of comparative example 1, the sample is first inserted into the analytical centrifugal analyzer. The analysis method is to scan once every 30 seconds, a total of 480 scans, and measure at 23°C and 4000rpm for 4 hours to simulate the stability after one year. According to the software provided by the instrument, the average instability index is 0.751, showing extremely poor stability. Figure 5 In the photo of Comparative Example 1, the emulsion showed an oil-water separation state after a simulated storage period of 1 year, and the oil layer can be clearly seen, indicating that its stability is poor. Because the strong thermal induction at a higher temperature causes the starch chains fixed on the oil-water interface to fully unfold, the strong hydrogen bond cross-linking between the starch chains causes the micro-nano starch to aggregate rapidly, so the internal discontinuous phase oil droplets cannot be fixed, and the oil droplets are precipitated immediately, causing the emulsion to break and stratify, and the stability is extremely poor.

[0078] Comparative Example 2

[0079] This comparative example is substantially the same as Example 1, except that the thermally induced temperature is lower.

[0080] (1) Disperse 0.2 g corn nano starch particles in 59 g deionized water and homogenize to obtain a nano starch particle suspension; the homogenization speed is 15000 rpm and the time is 10 min;

[0081] (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; the ultrasonic treatment time is 10 min;

[0082] (3) Add 40 g of sesame oil to the ultrasonic suspension, followed by homogenization to obtain a micro-nano starch particle-based Pickering emulsion; the homogenization speed is 15000 rpm, and the homogenization time is 10 min;

[0083] (4) The nano starch particle-based Pickering emulsion is thermally induced and then ice-cooled to obtain a nano starch-based Pickering emulsion with a micro thermal induced interfacial chain response; the thermal induction is performed by heating in a water bath for 20 min at a temperature of 20°C; and the ice bath cooling time is 20 min.

[0084] like Figure 3 The instability index of comparative example 2 is a simulated 1-year stability analysis in a centrifugal analyzer (LUMisizer, GmbH, Germany). The sample is irradiated with near-infrared light, and the entire sample can be observed and analyzed from top to bottom at the same time. The centrifugal acceleration method is used to simply test and quantify the separation behavior of the emulsion; the larger the instability index, the more unstable the emulsion. In the test of comparative example 2, the sample is first inserted into the analytical centrifugal analyzer. The analysis method is to scan once every 30 seconds, a total of 480 scans, and measure at 23°C and 4000rpm for 4 hours to simulate the stability after 1 year. According to the software provided by the instrument, the average instability index is 0.51, showing poor stability. Figure 5In the photo of Comparative Example 2, the emulsion showed an oil-water separation state after a simulated storage period of 1 year, and the water layer below can be clearly seen, indicating that its stability is poor. Because the lower thermal induction temperature is not enough to fully unfold the micro-nano starch chains, they cannot extend to the continuous phase water layer, resulting in only a few starch chains being cross-linked in the continuous phase during the subsequent cooling and regeneration process, and finally resulting in no improvement in stability compared to the original emulsion that was not thermally induced, and the stability is poor.

[0085] Comparative Example 3

[0086] This comparative example is substantially the same as Example 1, except that the thermal induction time is shorter.

[0087] (1) Disperse 0.2 g corn nano starch particles in 59 g deionized water and homogenize to obtain a nano starch particle suspension; the homogenization speed is 15000 rpm and the time is 10 min;

[0088] (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; the ultrasonic treatment time is 10 min;

[0089] (3) Add 40 g of sesame oil to the ultrasonic suspension, followed by homogenization to obtain a micro-nano starch particle-based Pickering emulsion; the homogenization speed is 15000 rpm, and the homogenization time is 10 min;

[0090] (4) The nano starch particle-based Pickering emulsion was thermally induced and then ice-cooled to obtain a nano starch-based Pickering emulsion with a micro thermal induced interfacial chain response; the thermal induction was performed by heating in a water bath for 10 min at a temperature of 90°C; and the ice bath cooling time was 20 min.

[0091] like Figure 3 The instability index of comparative example 3 is a simulated 1-year stability analysis in a centrifugal analyzer (LUMisizer, GmbH, Germany). The sample is irradiated with near-infrared light, and the entire sample can be observed and analyzed from top to bottom at the same time. The centrifugal acceleration method is used to simply test and quantify the separation behavior of the emulsion; the larger the instability index, the more unstable the emulsion. In the test of comparative example 3, the sample is first inserted into the analytical centrifugal analyzer. The analysis method is to scan once every 30 seconds, a total of 480 scans, and measure at 23°C and 4000rpm for 4 hours to simulate the stability after 1 year. According to the software provided by the instrument, the average instability index is 0.52, showing poor stability. Figure 5In the photo of Comparative Example 3, the emulsion showed an oil-water separation state after a simulated storage period of 1 year, and the water layer below can be clearly seen, indicating that its stability is poor. Because the short thermal induction time is not enough to fully unfold the micro-nano starch chains in the interface, they cannot extend to the continuous phase water layer, and only a few micro-nano starch chains are cross-linked in the continuous phase during the subsequent cooling and regeneration process, the stability is not improved compared to the emulsion without thermal induction, and the stability is poor.

[0092] Comparative Example 4

[0093] This comparative example is substantially the same as Example 1, except that the thermal induction time is longer.

[0094] (1) Disperse 0.2 g corn nano starch particles in 59 g deionized water and homogenize to obtain a nano starch particle suspension; the homogenization speed is 15000 rpm and the time is 10 min;

[0095] (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; the ultrasonic treatment time is 10 min;

[0096] (3) Add 40 g of sesame oil to the ultrasonic suspension, followed by homogenization to obtain a micro-nano starch particle-based Pickering emulsion; the homogenization speed is 15000 rpm, and the homogenization time is 10 min;

[0097] (4) The nano starch particle-based Pickering emulsion was thermally induced and then ice-cooled to obtain a nano starch-based Pickering emulsion with a micro thermal induced interfacial chain response; the thermal induction was performed by heating in a water bath for 60 min at a temperature of 90°C; and the ice bath cooling time was 20 min.

[0098] like Figure 3 The instability index of comparative example 4 is a simulated 1-year stability analysis in a centrifugal analyzer (LUMisizer, GmbH, Germany). The sample is irradiated with near-infrared light, and the entire sample can be observed and analyzed from top to bottom at the same time. The centrifugal acceleration method is used to simply test and quantify the separation behavior of the emulsion; the larger the instability index, the more unstable the emulsion. In the test of comparative example 4, the sample is first inserted into the analytical centrifugal analyzer. The analysis method is to scan once every 30 seconds, a total of 480 scans, and measure at 23°C and 4000rpm for 4 hours to simulate the stability after 1 year. According to the software provided by the instrument, the average instability index is 0.82, showing poor stability. Figure 5In the photo of Comparative Example 4, the emulsion showed an oil-water separation state after a simulated storage period of 1 year, and the oil layer on the top can be clearly seen, indicating that its stability is poor. Because the long-term thermal induction effect completely unfolds the starch chains fixed on the oil-water interface, the strong hydrogen bonds between the starch chains cause the unfolded micro-nano starch chains to aggregate rapidly, and the internal discontinuous phase oil droplets cannot be fixed, resulting in emulsion demulsification and stratification, and the stability is extremely poor.

[0099] Comparative Example 5

[0100] This comparative example is substantially the same as Example 1, except that natural cooling is used instead of ice bath cooling.

[0101] (1) Disperse 0.2 g corn nano starch particles in 59 g deionized water and homogenize to obtain a nano starch particle suspension; the homogenization speed is 15000 rpm and the time is 10 min;

[0102] (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; the ultrasonic treatment time is 10 min;

[0103] (3) Add 40 g of sesame oil to the ultrasonic suspension, followed by homogenization to obtain a micro-nano starch particle-based Pickering emulsion; the homogenization speed is 15000 rpm, and the homogenization time is 10 min;

[0104] (4) The nano starch particle-based Pickering emulsion is thermally induced and then ice-cooled to obtain a nano starch-based Pickering emulsion with a micro thermal induced interfacial chain response; the thermal induction is performed by heating in a water bath for 20 min at a temperature of 90°C; and the emulsion is naturally cooled to room temperature.

[0105] like Figure 3 The instability index of comparative example 5 is a simulated 1-year stability analysis in a centrifugal analyzer (LUMisizer, GmbH, Germany). The sample is irradiated with near-infrared light, and the entire sample can be observed and analyzed from top to bottom at the same time. The centrifugal acceleration method is used to simply test and quantify the separation behavior of the emulsion; the larger the instability index, the more unstable the emulsion. In the test of comparative example 5, the sample is first inserted into the analytical centrifugal analyzer. The analysis method is to scan once every 30 seconds, a total of 480 scans, and measure at 23°C and 4000rpm for 4 hours to simulate the stability after 1 year. According to the software provided by the instrument, the average instability index is 0.71, which shows poor stability. Figure 5In the photo of comparative example 5, the emulsion shows a state of oil-water separation after simulating a storage period of 1 year, and the oil layer above can be clearly seen, indicating that its stability is poor. Because when cooling naturally, cooling is too slow, which will lead to weakened stability. First, the cooling time is too long, and under the continuous heat effect, the starch chains fixed on the oil-water interface are completely unfolded. Under the action of strong hydrogen bonds between starch chains, the unfolded micro-nano starch chains are rapidly aggregated, and the internal discontinuous phase oil droplets cannot be fixed, causing the emulsion to break and stratify. Second, without rapid cooling, the unfolded micro-nano starch chains are difficult to cross-link autonomously, and therefore cannot form a network structure, which weakens the stability of the emulsion and makes the stability extremely poor.

[0106] In some comparative examples, too short an ice bath cooling time would result in insufficient cross-linking of the extended starch chains, which would not be able to reconnect and crystallize into a network structure, and thus fail to improve the stability of the emulsion.

[0107] Comparative Example 6

[0108] This comparative example is different from Example 1 in that no thermal induction is performed.

[0109] (1) Disperse 0.2 g corn nano starch particles in 59 g deionized water and homogenize to obtain a nano starch particle suspension; the homogenization speed is 15000 rpm and the time is 10 min;

[0110] (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; the ultrasonic treatment time is 10 min;

[0111] (3) Add 40 g of sesame oil to the ultrasonic suspension, followed by homogenization to obtain a micro-nano starch particle-based Pickering emulsion; the homogenization speed is 15000 rpm, and the homogenization time is 10 min;

[0112] like Figure 3 The instability index of comparative example 6 is a simulated 1-year stability analysis in a centrifugal analyzer (LUMisizer, GmbH, Germany). The sample is irradiated with near-infrared light, and the entire sample can be observed and analyzed from top to bottom at the same time. The centrifugal acceleration method is used to simply test and quantify the separation behavior of the emulsion; the larger the instability index, the more unstable the emulsion. In the test of comparative example 6, the sample is first inserted into the analytical centrifugal analyzer. The analysis method is to scan once every 30 seconds, a total of 480 scans, and measure at 23°C and 4000rpm for 4 hours to simulate the stability after 1 year. According to the software provided by the instrument, the average instability index is 0.53, showing poor stability. Figure 5In the photo of Comparative Example 6, the emulsion showed an oil-water separation state after simulating a storage period of 1 year, and the oil droplets precipitated on the wall can be clearly seen, indicating that its stability is poor. Because in the absence of thermal induction, the micro-nano starch is distributed in a granular manner around the oil droplets in the Pickering emulsion and presents a typical oil-in-water emulsion. Since it does not extend its starch chain in the water phase, its stability is poor.

[0113] The present invention uses edible oil, deionized water and micro-nano starch particles as raw materials, and uses homogenization and micro-heat induced interface chain cross-linking and other technical means to achieve an ultra-stable all-plant-based edible Pickering emulsion. The preliminary emulsion is obtained by high-speed homogenization of water, oil and micro-nano starch particles. The emulsion is then heated in a water bath at a certain stirring rate to induce the starch chains fixed in the interface to unfold. At this time, the water molecules will form hydrogen bonds with the hydroxyl groups (-OH) in the starch molecules, causing the starch chains to swell. In the presence of continuous phase water, the micro-nano starch molecules in the interface will gradually unfold toward the water phase, especially under certain heating conditions. For amylose, hydration relaxes its chain structure; for amylopectin, hydration makes the chain segments in its branched structure looser. After cooling in an ice bath, the starch chains will interact with each other again and recrystallize, a process similar to regeneration. During the re-interaction process, some of the unfolded starch chains will re-aggregate into a more ordered structure, forming a network-like region, further forming an ultra-stable Pickering emulsion with a storage time of more than one year. The amount of micro-nano starch used is far less than that of existing technologies, which can greatly save costs.

[0114] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a micro-nano starch particle-based Pickering emulsion with micro-heat-induced interfacial response, characterized in that: The steps include: (1) dispersing 0.2-1 parts by weight of micro-nano starch particles in 59 parts by weight of an aqueous phase and homogenizing the mixture to obtain a suspension of micro-nano starch particles; the micro-nano starch particles are derived from one or more of corn, wheat, potato, and potato; (2) subjecting the nano starch particle suspension to ultrasonic treatment to obtain an ultrasonic suspension; (3) adding 40 parts by weight of an oil phase to the ultrasonic suspension, followed by homogenization to obtain a nano starch particle-based Pickering emulsion; the oil phase is one of sesame oil, soybean oil, corn oil, olive oil, and rapeseed oil; (4) subjecting the nano starch particle-based Pickering emulsion to thermal induction and then cooling it in an ice bath to obtain a nano starch-based Pickering emulsion with a micro thermal induced interfacial chain response; the thermal induction is performed by heating in a water bath for 20 to 50 minutes at a temperature of 40 to 90° C.; and the ice bath cooling time is greater than or equal to 10 minutes.

2. The preparation method according to claim 1, characterized in that: The aqueous phase in step (1) is deionized water.

3. The preparation method according to claim 1, characterized in that: The homogenization speed in step (1) is 15000-18000 rpm, and the time is 5-10 min.

4. The preparation method according to claim 1, characterized in that: The ultrasonic treatment time in step (2) is 10 minutes.

5. The preparation method according to claim 1, characterized in that: The homogenization speed in step (3) is 15000-20000 rpm, and the homogenization time is 1-10 min.

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