阅读说明：本技术 纳米粒子与纳米纤维复合物稳定高内相乳液的制备方法 (Preparation method of stable high internal phase emulsion of nano particle and nano fiber composite ) 是由 李艳 孙格格 胡俊杰 李斌 刘石林 于 2020-07-30 设计创作，主要内容包括：本发明属于高内相乳液的技术领域,公开了一种纳米粒子与纳米纤维复合物稳定高内相乳液的制备方法,将玉米醇溶蛋白溶于蒸馏水中,经过反溶剂法制备玉米醇溶蛋白纳米粒子溶液；将甲壳素粉末溶于蒸馏中,调节pH并搅拌过夜,经过机械处理获得甲壳素纳米纤维悬浮液；将玉米醇溶蛋白纳米粒子与甲壳素纳米纤维混合,调节混合溶液pH；通过高速剪切,逐滴添加油脂,制备玉米醇溶蛋白粒子-甲壳素纳米纤维复合稳定的高内相乳液。本发明将通过pH调控使复合物形成特殊结构,用于稳定高内相皮克林乳液。本发明的乳液未使用表面活性剂,但是所获得乳液稳定性高,可稳定1个月以上,且对油脂抗氧化性能好。(The invention belongs to the technical field of high internal phase emulsion, and discloses a preparation method of a stable high internal phase emulsion of a nano particle and nanofiber composite, which comprises the steps of dissolving zein in distilled water, and preparing zein nano particle solution by an anti-solvent method; dissolving chitin powder in distillation, adjusting pH, stirring overnight, and mechanically treating to obtain chitin nanofiber suspension; mixing zein nano particles and chitin nano fibers, and adjusting the pH value of a mixed solution; and (3) dropwise adding grease by high-speed shearing to prepare the zein particle-chitin nanofiber composite stable high internal phase emulsion. The invention leads the complex to form a special structure by pH regulation and control, and is used for stabilizing high internal phase pickering emulsion. The emulsion of the invention does not use a surfactant, but the obtained emulsion has high stability, can be stabilized for more than 1 month and has good oxidation resistance to grease.)

1. A preparation method of a zein particle-chitin nanofiber composite stable high internal phase pickering emulsion is characterized in that the preparation method of the zein particle-chitin nanofiber composite stable high internal phase emulsion comprises the following steps:

(1) dissolving zein in an ethanol water solution, and preparing zein nanoparticle dispersion liquid by an anti-solvent method;

(2) dissolving chitin powder in distillation, adjusting pH, stirring overnight, and mechanically treating to obtain chitin nanofiber suspension;

(3) compounding the zein nano particles and the chitin nano fibers, and adjusting the pH value of a mixed solution;

(4) and shearing and homogenizing the solution system at a high speed, and adding grease to obtain the zein particle-chitin nanofiber composite stable high internal phase pickering emulsion.

2. The method of preparing a zein particle-chitin nanofiber composite stable high internal phase emulsion according to claim 1, wherein the zein nanoparticles in step (1) are prepared by the following steps: dissolving zein powder in 75 (v/v)% ethanol water solution, and performing rotary evaporation to remove ethanol and part of water to obtain zein nanoparticle dispersion.

3. The method of preparing a zein particle-chitin nanofiber composite stable high internal phase emulsion as claimed in claim 1, wherein the mass concentration of the zein nanoparticle dispersion in step (1) is 0.4% -4%.

4. The method for preparing a stable high internal phase emulsion of zein particle-chitin nanofiber composite according to claim 1, wherein the preparation method of the chitin nanofiber in step (2) comprises: dissolving chitin powder in distilled water, adjusting the pH value to 2.0-5.0, stirring overnight, homogenizing under high pressure, and crushing into nanofibers. The homogenizing pressure is 1000bar, and the homogenizing times are 25-50 times.

5. The method for preparing a stable high internal phase emulsion of zein particle-chitin nanofiber composite according to claim 1, wherein the mass concentration of the chitin nanofiber suspension in the step (2) is 0.2-0.6%.

6. The method for preparing a stable high internal phase emulsion of zein particle-chitin nanofiber composite according to claim 1, wherein the volume ratio of the zein particle dispersion to the chitin nanofiber suspension in step (3) is 1: 1-10: 1, and the pH value of the mixed solution is 4.0-9.0.

7. The method for preparing a zein particle-chitin nanofiber composite stable high internal phase emulsion as claimed in claim 1, wherein the volume ratio of the solution system to the oil in step (4) is 1:4, and the oil is edible oil such as soybean oil, medium chain glyceride and the like, or a mixture of edible oil and functional oil; the high-speed shearing rate in the step (4) is 12000rpm, and the shearing time is 3 min.

8. A zein particle-chitin nanofiber composite stable high internal phase emulsion obtained by the preparation method of any one of claims 1 to 7.

9. An entrapment system for active oils or functional components using the zein particle-chitin nanofiber composite of claim 8 to stabilize high internal phase pickering emulsion.

Technical Field

The invention belongs to the technical field of high internal phase emulsion, and particularly relates to a preparation method of a stable high internal phase emulsion of a nanoparticle and nanofiber composite. In particular to a preparation method of a stable high internal phase pickering emulsion of zein particles and chitin nanofiber composites.

Background

Currently, emulsifiers are commonly used in the food and pharmaceutical industries for encapsulation and delivery of bioactive compounds. The emulsion as a functional active ingredient carrying system can embed various fat-soluble substances, and obviously improves the solubility, the stability and the bioavailability of the core material. The properties of the emulsion can be improved by controlling the composition of the oil phase and the water phase in the emulsion system, the type of the emulsifier and the emulsification condition, so that an ideal product is obtained, and the emulsion has wide application prospects in the field of foods, such as functional food research and development, improvement of bioavailability of functional active ingredients, improvement of product quality and the like. Hydrogenated Oil (PHO) has become the major source of trans fatty acids in the food industry today, exposing mankind to many health risks, and the development of High Internal Phase Pickering Emulsions (HIPPEs) is one of the promising methods for direct conversion of liquid oils to solid fats without PHO. Conventional high internal phase emulsions are usually stabilized by high concentrations of surfactants, but they are generally unsuitable for consumption and are limited in many areas due to intrinsic safety issues. The pickering emulsion as stable solid particle emulsion has the advantages of no surfactant, no coalescence, etc. Thus, natural products (e.g., polysaccharides and proteins) have become the focus of research in this field in recent years, and few reports have been made on prolamin-stabilized high internal phase pickering emulsions.

Chinese patent application 20161375516 discloses a preparation method of edible protein stable high internal phase Pickering emulsion, which is characterized in that the pH is adjusted, chitosan is added to stabilize wheat alcohol soluble protein high internal phase emulsion, the emulsion prepared by a compound solution at the pH of 4.0-6.0 can be kept stable for two months, and the emulsion obtained by the preparation method at the pH of less than 4.0 is maintained for one week, so that the phenomenon of demulsification and oil leakage occurs.

The Chinese patent application 201611004761.X discloses a method for preparing high internal phase gel-like emulsion by using zein, the method prepares zein-pectin composite nanoparticle stable emulsion by an anti-solvent method, the high internal phase emulsion prepared by the composite under the condition of pH3.0-5.0 can be stable for more than 10 days, phase inversion occurs at pH6.0, and the separation of protein and oil layer can be obviously seen after the composite is placed.

Zein (zein) is a natural protein extracted from corn, is a storage protein in corn, and is produced in a large amount in nature. zein contains more than 50% of hydrophobic amino acid in molecules, has strong hydrophobicity, is insoluble in oil and water, and can be dissolved in 60% -90% of alcoholic solution. In addition, the hydrophilic and hydrophobic side chains contained in protein molecules provide possibility for self-assembly behavior, and are widely applied to embedding of active substances and stabilization of Pickering emulsion in recent years, but zein cannot be used alone for stabilizing high internal phase emulsion, because the isoelectric point of zein is about 6.0, the phenomenon of protein solubility reduction and even precipitation can occur near the isoelectric point, and zein has strong hydrophobicity and is very easy to generate phase inversion in the process of forming high internal phase emulsion.

The chitin nano-fiber can be uniformly dispersed in water, and the dispersion is easy to process and form, and has high aspect ratio, high surface area and low densityDegree and reactive surface (-OH, -NHCOCH)₃And residual-NH₂Groups) to facilitate surface functionalization. Chitin is a polysaccharide with positive charges found in nature at present, and molecules of chitin have unsaturated cationic groups, so that chitin has a strong adsorption effect on various harmful substances and harmful bacteria with negative charges, and can inhibit the activity of the harmful bacteria to lose the activity of the harmful bacteria, thereby achieving the antibacterial purpose. Thanks to excellent mechanical properties and versatility, chitin nanomaterials have shown promising applications, such as nanocomposites, drug carriers, tissue engineering and biomedical materials.

Through the above analysis, the problems and defects of the prior art are as follows:

(1) in the conventional preparation technology of high internal phase emulsion, a surfactant is mostly used for converting liquid oil into solid fat, which has adverse effect on human health.

(2) In the prior art, there are limited natural materials available for stabilizing high internal phase emulsions and the cost of natural materials is high compared to surfactants.

(3) High internal phase emulsions made from natural materials are typically stored for short periods of time and exhibit demulsification and oil leakage.

The difficulty in solving the above problems and defects is:

in order to avoid the adverse effect of PHO on human body, a natural safe sustainable material is adopted to prepare high internal phase emulsion, and the liquid grease is subjected to shaping treatment. The selected material needs to have good emulsifying capacity, the oil content of more than 74% can be stabilized, and the prepared high internal phase emulsion can be kept stable in a certain shelf life.

The significance of solving the problems and the defects is as follows:

according to the invention, zein particles and chitin nanofiber are compounded to form a special structure through pH regulation and control, and the special structure is used for stabilizing high internal phase pickering emulsion. The emulsion of the invention does not add surfactant and PHO, thus reducing the adverse effect of the surfactant and the PHO on the human health. The single zein particles have limited emulsifying ability with the chitin nanofibers and cannot stabilize high internal phase emulsions. The zein particle and chitin nanofiber compound prepared by the technology has better emulsifying capacity, can stabilize up to 80% of oil phase, and the obtained high internal phase emulsion has high stability, can be stabilized for more than 1 month, and has good oxidation resistance.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a preparation method of a stable high internal phase emulsion of a nanofiber composite.

The invention is realized in this way, a preparation method of stable high internal phase pickering emulsion compounded by zein particles and chitin nano fibers comprises the following steps:

(1) dissolving zein in an ethanol water solution, and preparing zein nano particle dispersion liquid by an anti-solvent method;

(2) dissolving chitin powder in distillation, adjusting pH, stirring overnight, and mechanically treating to obtain chitin nanofiber suspension;

(3) compounding the zein nano particles and the chitin nano fibers, and adjusting the pH of a mixed solution to 4.0-9.0;

(4) and shearing and homogenizing the solution system at a high speed, and dropwise adding oil to obtain the zein particle-chitin nanofiber composite stable high internal phase emulsion.

Further, the preparation method of the zein nanoparticles in the step (1) comprises the following steps: dissolving zein powder in 75 (v/v)% ethanol water solution, and performing rotary evaporation to remove ethanol and part of water to obtain zein nanoparticle dispersion.

Further, the mass concentration of the zein nanoparticle solution in the step (1) is 0.4-4%.

Further, the preparation method of the chitin nano-fiber in the step (2) comprises the following steps: dissolving chitin powder in distilled water, adjusting the pH value to 2.0-5.0, stirring overnight, homogenizing under high pressure, and crushing into nanofibers. The homogenizing pressure is 1000bar, and the homogenizing times are 25-50 times.

Further, the mass concentration of the chitin nano-fiber suspension in the step (2) is 0.2-0.6%.

Further, the volume ratio of the zein particle dispersion liquid to the chitin nanofiber suspension in the step (3) is 1: 1-5: 1.

Further, the volume ratio of the solution system to the oil in the step (4) is 1:4, and the ratio of the soybean oil to the Antarctic shrimp oil in the mixed oil entrapped in the antioxidation determination experiment is 7: 3.

Further, the high speed shearing rate in the step (4) is 12000rpm, and the shearing time is 3 min.

The invention also aims to provide the zein particle-chitin nanofiber composite stable high internal phase emulsion prepared by the preparation method.

The invention also aims to provide an application of the oil emulsion in delaying oil product oxidation and encapsulating active substances, which comprises an emulsifier and an embedding system.

By combining all the technical schemes, the invention has the advantages and positive effects that:

according to the invention, the zein nanoparticle and chitin nanofiber composite after pH regulation is used as an emulsifier, the edible oil is emulsified to obtain the stable high internal phase emulsion, and the volume fraction of the emulsified dispersed phase can reach 80v/v at most.

Compared with the prior art, the invention also has the following advantages:

the invention successfully converts liquid oil into solid fat based on the stable high internal phase pickering emulsion compounded by zein particles and chitin nano fibers, and has no surfactant.

The materials for stabilizing the high internal phase emulsion are all natural substances, are green and safe, are safe to use, and can be widely applied to the field of food.

The stable high internal phase emulsion of the zein nano particle-chitin nano fiber has good stability, and does not have the phenomena of demulsification and oil leakage after being stored for more than 1 month.

The high internal phase pickering emulsion prepared by the invention has good oxidation resistance in an accelerated oxidation experiment.

The present invention can stabilize up to 80% of the oil phase and prepare high internal phase emulsions. The overall effect is as follows: elastic gel state emulsion is formed, the gel state emulsion is not deformed after inversion, and the apparent shape of the sample is not changed after one month of storage.

According to the invention, zein and chitin are prepared into the shapes of nano particles and nano fibers, the nano particles are adsorbed on the nano fibers by pH adjustment, and the compound of the zein and the chitin has excellent emulsifying capacity and can stabilize up to 80% of oil phase. We find that the high internal phase emulsion is stabilized by compounding zein particles and chitin nano fibers, and the pH and the compounding ratio of the zein particles and the chitin nano fibers are not adjustable.

The zein nanoparticles and the chitin nanofibers independently used cannot stabilize the high internal phase emulsion, and a sample shows that obvious oil drops break and the sample is in a flowing state and needs to be compounded; in addition, the compound can stabilize 80% of oil phase at the pH of 6, and the sample has obvious demulsification and oil leakage phenomena at the pH of 4 and 8.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained from the drawings without creative efforts.

Fig. 1 is a flowchart of a method for preparing a stable high internal phase emulsion of zein particle-chitin nanofiber composite according to an embodiment of the present invention.

Fig. 2A is a diagram of the appearance of a new high internal phase Pickering emulsion with stable zein particle-chitin nanofiber composite at different pH values in example 1 according to an embodiment of the present invention.

Fig. 2B is an appearance view of the zein particle-chitin nanofiber composite stable high internal phase Pickering emulsions of different pH in example 1 stored for 1 month provided by the present invention.

Fig. 2C is a sample diagram of the high internal phase Pickering emulsion with stable zein particle-chitin nanofiber composite at different pH values in example 1, provided by the embodiment of the present invention, having excellent plasticity.

Fig. 3A is a new external view of a high internal phase emulsion prepared from pure zein nanoparticles and pure chitin nanofibers in comparative example 1 provided by the present invention.

Fig. 3B is an appearance of a high internal phase emulsion prepared from pure zein nanoparticles and pure chitin nanofibers in comparative example 1 as provided by the present invention after 1 month storage.

Fig. 4A shows the change of the content of hydroperoxide in the oil and fat obtained by the stable high internal phase emulsion of zein particle-chitin nanofiber composite in example 2 and the simple oil and fat treated at the constant temperature of 40 ℃ for 21 days.

Fig. 4B is a curve showing the change of the malondialdehyde content in the oil after the zein particle-chitin nanofiber composite stable high internal phase emulsion and the simple oil are treated at the constant temperature of 60 ℃ for 21 days in example 2 provided by the embodiments of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In view of the problems of the prior art, the present invention provides a method for preparing a stable high internal phase emulsion of a particle and nanofiber composite, which is described in detail below with reference to the accompanying drawings.

As shown in fig. 1, the present invention provides a method for preparing a stable high internal phase emulsion of zein particle-chitin nanofiber composite, comprising the following steps:

s101, dissolving zein in an ethanol water solution, and preparing a zein nanoparticle dispersion liquid by an anti-solvent method.

S102, dissolving chitin powder in distillation, adjusting the pH value to 2.0-5.0, stirring overnight, and mechanically treating to obtain chitin nanofiber suspension.

S103, compounding the zein nanoparticles and the chitin nanofibers, and adjusting the pH of the mixed solution to be 4.0-9.0.

S104, shearing and homogenizing the solution system at a high speed, and dropwise adding oil to obtain the zein particle-chitin nanofiber composite stable high internal phase emulsion.

The preparation method of the stable high internal phase emulsion of the particle and nanofiber composite provided by the invention can be implemented by other steps by persons skilled in the art, and the invention of fig. 1 is provided by only one specific example.

The present invention will be further described with reference to specific examples and experiments.