阅读说明：本技术 一种不饱和脂肪酸微胶囊的制备方法 (Preparation method of unsaturated fatty acid microcapsule ) 是由 肖子豪 张明 王丽飞 陈海勇 张军桥 张荣华 于亚芹 戴辉 曾忠俊 于 2020-12-22 设计创作，主要内容包括：本发明公开了一种不饱和脂肪酸微胶囊的制备方法,步骤为：在设有气固分离器的真空乳化罐中加入水,用惰性气体将壁材、乳化剂和抗氧化剂通过气固分离器吹入真空乳化罐内的水中,剪切乳化得到预乳化液；向预乳化液中添加不饱和脂肪酸芯材,依次经过剪切乳化、均质后得到乳化液；对乳化液进行灭菌；对灭菌后的乳化液进行喷雾干燥,所得粉末产物过筛后得到所述不饱和脂肪酸微胶囊。本发明制备乳化液时采用设有气固分离器的真空乳化罐进行剪切乳化,有效提高了原料利用率；并且对乳化液灭菌后再进行喷雾干燥,避免了微胶囊在微生物作用下变质,延长了产品货架期。(The invention discloses a preparation method of unsaturated fatty acid microcapsules, which comprises the following steps: adding water into a vacuum emulsification tank provided with a gas-solid separator, blowing wall materials, an emulsifier and an antioxidant into the water in the vacuum emulsification tank through the gas-solid separator by using inert gas, and shearing and emulsifying to obtain pre-emulsion; adding an unsaturated fatty acid core material into the pre-emulsion, and sequentially carrying out shearing emulsification and homogenization to obtain an emulsion; sterilizing the emulsion; and (4) carrying out spray drying on the sterilized emulsion, and sieving the obtained powder product to obtain the unsaturated fatty acid microcapsule. The invention adopts the vacuum emulsification tank with the gas-solid separator to carry out shearing emulsification when preparing the emulsion, thereby effectively improving the utilization rate of raw materials; and the emulsion is sterilized and then spray-dried, so that the microcapsules are prevented from deteriorating under the action of microorganisms, and the shelf life of the product is prolonged.)

1. A preparation method of unsaturated fatty acid microcapsules is characterized by comprising the following steps:

s1: adding water into a vacuum emulsification tank provided with a gas-solid separator, blowing wall materials, an emulsifier and an antioxidant into the water in the vacuum emulsification tank through the gas-solid separator by using inert gas, and shearing and emulsifying to obtain pre-emulsion;

s2: adding an unsaturated fatty acid core material into the pre-emulsion, and sequentially carrying out shearing emulsification and homogenization to obtain an emulsion;

s3: sterilizing the emulsion;

s4: and (3) taking inert gas as a drying medium, carrying out spray drying on the sterilized emulsion, and sieving the obtained powder product to obtain the unsaturated fatty acid microcapsule.

2. The preparation method of the unsaturated fatty acid microcapsule according to claim 1, wherein the vacuum emulsification tank comprises a tank body (1), the top of the tank body is provided with a liquid feeding port (2) and a vacuum pumping port (3), the bottom of the tank body is provided with a high-shear tank bottom emulsifying machine (4) and a discharging port (5), and a gas-solid separator is arranged in the tank body; the gas-solid separator comprises a solid gas inlet pipe (601), an exhaust pipe (602) and a powder outlet pipe (603), wherein one end of the solid gas inlet pipe is communicated with one end of the gas inlet pipe, the other end of the solid gas inlet pipe extends out of the tank body from the side wall of the tank body and is provided with a solid gas inlet, the other end of the exhaust pipe extends towards the top of the tank body and is provided with an exhaust port, the other end of the powder outlet pipe extends towards the bottom of the tank body and is provided with a powder outlet, and the powder outlet is positioned above the.

3. The method for preparing unsaturated fatty acid microcapsules according to claim 2, wherein one end of a solid-gas feed pipe, an exhaust pipe and a powder outlet pipe of the gas-solid separator are communicated through a conical separation part (604), the solid-gas feed pipe is communicated with the bottom of the side surface of the conical separation part, the exhaust pipe is communicated with the top of the conical separation part, and the powder outlet pipe is communicated with the bottom of the conical separation part.

4. The method for producing unsaturated fatty acid microcapsules according to claim 3, wherein the bottom surface of said conical separation section is curved.

5. The method for preparing unsaturated fatty acid microcapsules according to claim 2, wherein the top of the tank body is provided with a vacuum pressure gauge (7), and the lower part of the side wall of the tank body is provided with a sampling port (8).

6. The method for producing unsaturated fatty acid microcapsules according to claim 1 or 2, wherein the pressure in the vacuum emulsification tank is from-0.03 to-0.09 MPa.

7. The method according to claim 1, wherein the amount of water used in S1 is 1-4 times the weight of the wall material, the concentration of the emulsifier in the pre-emulsion is 1-2 wt%, and the concentration of the stabilizer in the pre-emulsion is 2-4 wt%; the wall material comprises the following components in percentage by mass (10-20): (10-20): (60-80) lactose, maltodextrin and sodium starch octenyl succinate; the emulsifier is at least one of monoglyceride/diglycerol fatty acid ester, phospholipid and citric acid monoglyceride; the antioxidant is sodium ascorbate and/or vitamin E.

8. The preparation method of the unsaturated fatty acid microcapsule according to claim 1, wherein the mass ratio of the core material to the wall material added in S2 is (30-50): (50-70).

9. The method for preparing unsaturated fatty acid microcapsules according to claim 1, wherein the sterilization temperature in S3 is 71-84 ℃, and the sterilization time is 1-10 min.

10. The method for preparing unsaturated fatty acid microcapsules according to claim 1, wherein the air inlet temperature of the spray drying in S4 is 100-230 ℃, and the air outlet temperature is 60-100 ℃.

Technical Field

The invention relates to the technical field of microcapsule preparation, in particular to a preparation method of an unsaturated fatty acid microcapsule.

Background

Unsaturated fatty acid is a fatty acid constituting body fat, is an essential fatty acid for human body, such as DHA, ARA, CLA, GLA, ALA, EPA, DPA, etc., and has important nutritional value, and thus has wide application in the field of food. Because unsaturated fatty acid is very easy to be oxidized, a large amount of hydroperoxide is generated after oxidation, and then the hydroperoxide is broken and decomposed to generate a series of volatile and non-volatile substances with short carbon chains, such as aldehydes, ketones, alcohols, acids and the like, most of the substances have pungent smell and are harmful to human bodies, so that the food is generally added with the microcapsule-embedded powder product to avoid oxidation.

The existing unsaturated fatty acid microcapsule generally takes substances such as protein, sugar or glue as wall materials, and is embedded by adopting a spray drying method, for example, the publication of Chinese patent document, "a composition for preparing DHA and ARA microcapsule and a preparation method thereof", is CN106858602A and consists of an antioxidant, an emulsifier, a wall material and a core material; the antioxidant consists of BHA, vitamin E and beta-carotene; the emulsifier is glycerin unsaturated fatty acid ester; the wall material consists of carrageenan, beta-cyclodextrin and soybean protein isolate; the core material comprises algae oil DHA, ARA and corn germ oil. The invention can well protect the core material, prolong the oxidation of unsaturated fatty acid, effectively remove fishy smell and is beneficial to adding the unsaturated fatty acid microcapsule into food.

However, in the process of preparing unsaturated fatty acid microcapsules in the prior art, powdery wall material raw materials are easy to generate dust during the preparation of emulsion, the raw materials are seriously wasted, and the environment is polluted; and the emulsion is not sterilized before spray drying, and the prepared microcapsule is easy to deteriorate under the action of microorganisms, so that the shelf life stability of the product is influenced.

Disclosure of Invention

The invention aims to overcome the defects that in the preparation process of unsaturated fatty acid microcapsules in the prior art, powdery wall material raw materials are easy to generate dust during the preparation of emulsion, the raw materials are seriously wasted, and the environment is polluted; the emulsion is not sterilized before spray drying, and the prepared microcapsule is easy to deteriorate under the action of microorganisms, so that the shelf life stability of the product is influenced; and the emulsion is sterilized and then spray-dried, so that the microcapsules are prevented from deteriorating under the action of microorganisms, and the shelf life of the product is prolonged.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of unsaturated fatty acid microcapsules comprises the following steps:

s1: adding water into a vacuum emulsification tank provided with a gas-solid separator, blowing wall materials, an emulsifier and an antioxidant into the water in the vacuum emulsification tank through the gas-solid separator by using inert gas, and shearing and emulsifying to obtain pre-emulsion;

s2: adding an unsaturated fatty acid core material into the pre-emulsion, and sequentially carrying out shearing emulsification and homogenization to obtain an emulsion;

s3: sterilizing the emulsion;

s4: and (3) taking inert gas as a drying medium, carrying out spray drying on the sterilized emulsion, and sieving the obtained powder product to obtain the unsaturated fatty acid microcapsule.

According to the invention, the unsaturated fatty acid microcapsule is prepared by using a spray drying method, and the emulsion is sterilized at high temperature before spray drying, so that microorganisms in the emulsion are killed, the prepared microcapsule can be effectively prevented from deteriorating under the action of microorganisms in the storage process, and the shelf life stability of the microcapsule is improved. Meanwhile, the emulsion is prepared in the vacuum emulsification tank provided with the gas-solid separator, the powdery wall material raw material is directly blown into water in the vacuum emulsification tank from the gas-solid separator by using inert gas, and the powdery raw material is fed below the liquid level, so that the dust raising phenomenon during feeding can be effectively avoided, the raw material utilization rate is improved, and the pollution to the environment is reduced.

Preferably, the vacuum emulsification tank comprises a tank body, the top of the tank body is provided with a liquid feed port and a vacuumizing port, the bottom of the tank body is provided with a high-shear kettle bottom emulsifying machine and a discharge port, and a gas-solid separator is arranged in the tank body; the gas-solid separator comprises a solid gas inlet pipe, an exhaust pipe and a powder outlet pipe, wherein one end of the solid gas inlet pipe is communicated with one end of the exhaust pipe, the other end of the solid gas inlet pipe extends out of the tank body from the side wall of the tank body and is provided with a solid gas inlet, the other end of the exhaust pipe extends towards the top of the tank body and is provided with an exhaust port, the other end of the powder outlet pipe extends towards the bottom of the tank body and is provided with a powder outlet, and the powder outlet is positioned above the high.

After powdery raw materials are directly blown into water through gas, the viscosity of the solution of the wall materials dissolved in the water is high, and the gas is difficult to be discharged from the solution under the high-speed shearing action of a high-shear kettle bottom emulsifying machine positioned at the bottom of the tank body, and can be sucked into the high-shear kettle bottom emulsifying machine to participate in emulsification, so that a large amount of bubbles exist in the prepared emulsion, and the embedding rate of the finally prepared microcapsule is seriously influenced.

Therefore, the invention adopts the gas-solid separator comprising the solid gas feeding pipe, the exhaust pipe and the powder outlet pipe to feed, and can perform gas-solid separation after the powdery raw material is blown into the tank body, so that gas is effectively discharged from the solution, and bubbles in the emulsion are avoided. When the vacuum emulsifying tank is used, water is firstly added into the tank body until the liquid level is positioned above the solid gas feed inlet and the powder outlet and below the exhaust port, then the powdery raw material is blown into the tank body from the solid gas feed pipe through inert gas, the blown-in solid powder flows out from the powder outlet to the position above the high-shear kettle bottom emulsifying machine along the powder outlet pipe extending to the bottom of the tank body under the action of gravity, and is dissolved in the water under the high-speed shearing action of the high-shear kettle bottom emulsifying machine; and the inert gas moves upwards along the exhaust pipe extending to the top of the tank body, is exhausted from the exhaust port extending above the liquid level and is pumped out from the tank body under the action of the vacuum pump connected with the vacuumizing port, so that gas-solid separation is effectively realized, and the gas is prevented from being sucked by the high-shear kettle bottom emulsifying machine at the bottom of the tank body to participate in emulsification and influence the embedding effect of the microcapsules.

Preferably, one end of a solid-gas feeding pipe, one end of an exhaust pipe and one end of a powder outlet pipe of the gas-solid separator are communicated through the conical separation part, the solid-gas feeding pipe is communicated with the bottom of the side face of the conical separation part, the exhaust pipe is communicated with the top of the conical separation part, and the powder outlet pipe is communicated with the bottom of the conical separation part. According to the invention, one ends of the solid gas feeding pipe, the exhaust pipe and the powder outlet pipe are communicated through the conical separation part, and after the powdery raw material is blown by inert gas, the inert gas can spirally rise along the side wall of the conical separation part and is finally discharged from the exhaust pipe, so that the movement path of the gas is increased, the gas-solid separation effect is improved, and the gas can be completely discharged; and the conical separation part can play a buffering role on the powder, so that the powder is prevented from blocking the connection part of the solid gas feeding pipe, the exhaust pipe and the powder outlet pipe.

Preferably, the bottom surface of the tapered separating portion has an arc shape. The conical separation part adopts an arc bottom surface, so that the powder can be guided, and the powder can be discharged from the powder outlet pipe at the bottom of the conical separation part under the action of gravity more easily.

Preferably, the top of the tank body is provided with a vacuum pressure gauge, and the lower part of the side wall of the tank body is provided with a sampling port.

Preferably, the pressure in the vacuum emulsification tank is between-0.03 and-0.09 MPa.

Preferably, the amount of the water in the S1 is 1-4 times of the mass of the wall material, the concentration of the emulsifier in the pre-emulsion is 1-2 wt%, and the concentration of the stabilizer in the pre-emulsion is 2-4 wt%; the wall material comprises the following components in percentage by mass (10-20): (10-20): (60-80) lactose, maltodextrin and sodium starch octenyl succinate; the emulsifier is at least one of monoglyceride/diglycerol fatty acid ester, phospholipid and citric acid monoglyceride; the antioxidant is sodium ascorbate and/or vitamin E. According to the invention, the wall material and the emulsifier are compounded, so that the emulsifying property is improved, and the high temperature resistance of the wall material is also improved.

Preferably, the mass ratio of the core material to the wall material added in the S2 is (30-50): (50-70).

Preferably, the sterilization temperature in S3 is 71-84 ℃, and the sterilization time is 1-10 min.

Preferably, the air inlet temperature of the spray drying in the S4 is 100-230 ℃, and the air outlet temperature is 60-100 ℃.

Therefore, the invention has the following beneficial effects:

(1) the method comprises the steps of preparing emulsion in a vacuum emulsification tank provided with a gas-solid separator, directly blowing powdery wall material raw materials into water in the vacuum emulsification tank from the gas-solid separator by using inert gas, feeding the materials below the liquid level to effectively avoid the dust raising phenomenon when the powdery raw materials are fed, improving the utilization rate of the raw materials and reducing the pollution to the environment; the gas-solid separator can realize gas-solid separation, so that gas is prevented from being sucked by a high-shear kettle bottom emulsifying machine at the bottom of the tank body to participate in emulsification, and the embedding effect of microcapsules is prevented from being influenced;

(2) the emulsion is sterilized at high temperature before spray drying, so that microorganisms in the emulsion are killed, the prepared microcapsule is effectively prevented from deteriorating under the action of microorganisms in the storage process, and the shelf life stability of the microcapsule is improved.

Drawings

FIG. 1 is a schematic view of the structure of a vacuum emulsification tank used in example 1.

FIG. 2 is a schematic view of the structure of a vacuum emulsification tank used in example 2.

FIG. 3 is a schematic view of the structure of the vacuum emulsification tank used in comparative example 1.

In the figure: 1 tank body, 2 liquid feed inlets, 3 vacuumizing ports, 4 high-shear kettle bottom emulsifying machines, 5 discharge ports, 601 solid gas feed pipes, 602 exhaust pipes, 603 powder outlet pipes, 604 conical separation parts, 7 vacuum pressure gauges, 8 sampling ports, 9 tank body mounting racks and 10 lifting lugs.

Detailed Description

The invention is further described with reference to the following detailed description and accompanying drawings.

Example 1:

as shown in fig. 1, the vacuum emulsification tank used in the preparation of the emulsion in example 1 includes a tank body 1 and a tank body mounting bracket 9 provided outside the tank body. The tank body mounting bracket is provided with two lifting lugs 10 which are symmetrically arranged along the radial direction of the tank body. The top of the tank body is provided with a liquid feed port 2, a vacuum pumping port 3 and a vacuum pressure gauge 7, the bottom of the tank body is provided with a high-shear kettle bottom emulsifying machine 4 and a discharge port 5, the lower part of the side wall of the tank body is provided with a sampling port 8, and the tank body is internally provided with a gas-solid separator.

The gas-solid separator comprises a solid-gas feeding pipe 601, an exhaust pipe 602 and a powder outlet pipe 603, one end of the solid-gas feeding pipe is communicated with the bottom of the tank body, and the other end of the solid-gas feeding pipe extends out of the tank body from the side wall of the tank body and is provided with a solid-gas feeding hole; the other end of blast pipe extends and is equipped with the gas vent to jar body top along vertical direction, and the other end that goes out the powder pipe extends and is equipped with the powder export to jar body bottom, goes out the powder pipe and is 135 with the contained angle between solid gas inlet pipe and the blast pipe, and the powder export is located the top of high shear cauldron bottom emulsion machine.

A method for preparing DHA microcapsules by using the vacuum emulsification tank comprises the following steps:

s1: adding water into a vacuum emulsification tank until the liquid level is positioned above a solid gas feed inlet and a powder outlet and below an exhaust port, blowing wall materials into the water in the tank body along a solid gas feed pipe by using nitrogen, adjusting the pH value to 5.3, and shearing and emulsifying to obtain pre-emulsion; wherein the wall material comprises lactose, maltodextrin and sodium starch octenylsuccinate in a mass ratio of 15:15:70, the amount of water is 2 times of the mass of the wall material, the concentration of the monoglyceride and diglycerol fatty acid ester in the pre-emulsion is 1.5 wt%, and the concentration of the sodium ascorbate in the pre-emulsion is 3 wt%;

s2: adding DHA (docosahexaenoic acid) serving as an unsaturated fatty acid core material into the pre-emulsion, adding the mono-diglycerol fatty acid ester and the sodium ascorbate, and sequentially performing shearing emulsification and homogenization to obtain an emulsion, wherein the mass ratio of the DHA to the wall material is 40: 60;

s3: sterilizing the emulsion at 80 deg.C for 5 min;

s4: and (3) taking nitrogen as a drying medium, carrying out spray drying on the sterilized emulsion, and sieving the obtained powder product to obtain the unsaturated fatty acid microcapsule, wherein the air inlet temperature of the spray drying is 150 ℃, and the air outlet temperature of the spray drying is 80 ℃.

Example 2:

as shown in fig. 2, the gas-solid separator in the vacuum emulsification tank used in the preparation of the emulsion in example 2 includes a solid-gas feed pipe 601, an exhaust pipe 602, and a powder discharge pipe 603, one end of which is communicated with a tapered separation portion 604 having an arc-shaped bottom surface, the solid-gas feed pipe is communicated with the bottom of the side surface of the tapered separation portion, the exhaust pipe is communicated with the top of the tapered separation portion, and the powder discharge pipe is communicated with the bottom of the tapered separation portion. The other end of the solid gas inlet pipe extends out of the tank body from the side wall of the tank body and is provided with a solid gas inlet, the other end of the exhaust pipe extends towards the top of the tank body and is provided with an exhaust port, the other end of the powder outlet pipe extends towards the bottom of the tank body and is provided with a powder outlet, and the powder outlet is positioned above the high-shear kettle bottom emulsifying machine. The rest of the structure is the same as in embodiment 1.

A method for preparing ARA microcapsules by using the vacuum emulsification tank comprises the following steps:

s1: adding water into a vacuum emulsification tank until the liquid level is positioned above a solid gas feed inlet and a powder outlet and below an exhaust port, blowing wall materials into the water in the tank body along a solid gas feed pipe by using nitrogen, adjusting the pH value to 5.4, and shearing and emulsifying to obtain pre-emulsion; wherein the wall material comprises lactose, maltodextrin and sodium starch octenylsuccinate in a mass ratio of 20:20:60, the amount of water is 1 time of the mass of the wall material, the concentration of the monoglyceride and diglycerol fatty acid ester in the pre-emulsion is 0.5 wt%, the concentration of the phospholipid in the pre-emulsion is 0.5 wt%, and the concentration of the vitamin E in the pre-emulsion is 2 wt%;

s2: adding ARA into the pre-emulsion as an unsaturated fatty acid core material, adding mono-diglycerol fatty acid ester, phospholipid and vitamin E, sequentially carrying out shearing emulsification and homogenization to obtain an emulsion, wherein the mass ratio of the ARA to the wall material is 30: 70;

s3: sterilizing the emulsion at 71 deg.C for 10 min;

s4: and (3) taking nitrogen as a drying medium, carrying out spray drying on the sterilized emulsion, and sieving the obtained powder product to obtain the unsaturated fatty acid microcapsule, wherein the air inlet temperature of the spray drying is 100 ℃, and the air outlet temperature of the spray drying is 60 ℃.

Example 3:

the vacuum emulsification tank used in example 3 has the same structure as in example 2. A method for preparing EPA microcapsules by using the vacuum emulsification tank comprises the following steps:

s1: adding water into a vacuum emulsification tank until the liquid level is positioned above a solid gas feed inlet and a powder outlet and below an exhaust port, blowing wall materials into the water in the tank body along a solid gas feed pipe by using nitrogen, adjusting the pH value to 5.0, and shearing and emulsifying to obtain pre-emulsion; wherein the wall material comprises lactose, maltodextrin and sodium starch octenylsuccinate in a mass ratio of 10:10:80, the amount of water is 4 times of the mass of the wall material, the concentration of the citric acid monoglyceride in the pre-emulsion is 2wt%, and the concentration of the vitamin E in the pre-emulsion is 4 wt%;

s2: adding EPA serving as an unsaturated fatty acid core material into the pre-emulsion, adding citric acid monoglyceride and vitamin E, and sequentially performing shearing emulsification and homogenization to obtain an emulsion, wherein the mass ratio of the EPA to the wall material is 50: 50;

s3: sterilizing the emulsion at 84 deg.C for 1 min;

s4: and (3) taking nitrogen as a drying medium, carrying out spray drying on the sterilized emulsion, and sieving the obtained powder product to obtain the unsaturated fatty acid microcapsule, wherein the air inlet temperature of the spray drying is 230 ℃, and the air outlet temperature of the spray drying is 100 ℃.

Comparative example 1:

as shown in fig. 3, the vacuum emulsification tank used in comparative example 1 was prepared by the same method as in example 2 except that no gas-solid separator was provided and the wall material was directly blown into the water in the tank body through the solid-gas feed pipe 601.

The embedding rate and the surface oil content of the unsaturated fatty acid microcapsules prepared in the above examples and comparative examples were measured, and the results are shown in table 1.

Table 1: and testing results of the embedding rate of the microcapsules and the surface oil content.

Item	Example 1	Example 2	Example 3	Comparative example 1
					Embedding Rate (%)	98.4	98.8	98.2	89.2
Surface oil content (%)	0.95	0.87	0.94	9.65

The unsaturated fatty acid microcapsules prepared in the examples and comparative examples were subjected to oxidation accelerated stability test according to the method of GB/T5009.37-2003, and the product was subjected to accelerated oxidation in an oven at 62 ℃ to obtain the results shown in Table 2.

Table 2: oxidation accelerated stability test results.

As can be seen from tables 1 and 2, the unsaturated fatty acid microcapsules prepared by the method and the apparatus of the present invention in examples 1 to 3 have high embedding rate, low surface oil content, no oxidation of the product, and long shelf life. And the vacuum emulsification tank in the comparative example 1 is not provided with a gas-solid separator, so that nitrogen and powdery raw materials cannot be effectively separated in the preparation process, and the nitrogen is sucked by a high-shear kettle bottom emulsifying machine at the bottom of the tank body to participate in emulsification, so that the embedding rate of microcapsules is remarkably reduced, and the shelf life of products is influenced.