A polyunsaturated fatty acid oil microcapsule and a preparation method thereof

Abstract

The application provides a polyunsaturated fatty acid oil microcapsule and a preparation method. The preparation method of the polyunsaturated fatty acid oil microcapsule comprises the following steps: (1) adding a water retention agent into an aqueous solution of a water-soluble protein wall material, and uniformly mixing to obtain an aqueous phase; (2) adding polyunsaturated fatty acid oil into the aqueous phase, and shearing and emulsifying; (3) adding cellulose and a derivative thereof into the system obtained in the step (2), and shearing to obtain an emulsion; the content of the cellulose and the derivative thereof in the polyunsaturated fatty acid oil microcapsule is 0.05-0.3 wt%; the content of the polyunsaturated fatty acid oil in the polyunsaturated fatty acid oil microcapsule is not less than 40 wt%, and the content of a fatty acid with a carbon chain length of more than 20 and an unsaturated double bond of more than 4 in the polyunsaturated fatty acid oil is not less than 40%. The high oil-loading microcapsule product obtained by the preparation method has good sensory and good stability during a shelf life.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of preparation of polyunsaturated fatty acid, more particularly, to a polyunsaturated fatty acid oil microcapsule and a preparation method. BACKGROUND

[0002] Polyunsaturated fatty acid oil, such as arachidonic acid oil, docosahexaenoic acid oil, etc. has a wide range of biological functions in the biological system, can regulate the lipid metabolism, immunity of the body, has the functions of anti-cancer, prevention and treatment of cardiovascular diseases, promotion of body growth and development, and regulation of gene expression, etc. The many functional characteristics of polyunsaturated fatty acid have been widely understood by consumers. Arachidonic acid oil, docosahexaenoic acid oil, etc. are easily oxidized due to their own structure and produce an unpleasant smell, which affects the function of the oil. The microcapsule technology is usually used to protect polyunsaturated fatty acid oil such as arachidonic acid oil, docosahexaenoic acid oil, etc. by using a wrapping material, so as to improve the stability and flavor of the oil.

[0003] High-content polyunsaturated fatty acid oil microcapsule preparation methods have appeared in the prior art. For example, CN103549442A uses spray drying to prepare 33-50% oil-loaded DHA algal oil powder; CN102228257A improves the stability of high-content microcapsules by improving the antioxidant; CN110613025A uses a compound emulsifier to reduce the surface oil of high-content microcapsules; and CN110613025A microcapsule powder loads 45-80% of MCT, olive oil and other oils.

[0004] However, the hydrophobic oil accounts for 50% or more in the system during the preparation of high-oil-content polyunsaturated fatty acid oil microcapsules, which is quite different from the system established by conventional polyunsaturated fatty acid products. The water phase in the emulsion system tends to migrate to the surface, and it is easy to lose water quickly during the drying process. The product will be over-dried, which not only affects the sensory of the product, but also may cause discoloration during the shelf life, affecting the downstream application. This technical problem does not exist or is difficult to detect in conventional pufa microcapsules or conventional content of carotenoid lipid-soluble nutrient microcapsules as disclosed in CN107594597B. SUMMARY

[0005] In order to solve the problem that high-oil-content polyunsaturated fatty acid oil microcapsules, especially those with protein as emulsifier, are easy to over-dry during the preparation process, causing changes in product sensory, the present application provides a polyunsaturated fatty acid oil microcapsule and a preparation method.

[0006] The first object of the present application is to provide a preparation method of polyunsaturated fatty acid oil microcapsule, comprising the following steps:

[0007] (1) adding a water retention agent to an aqueous solution of a water-soluble protein wall material, mixing to obtain an aqueous phase;

[0008] (2) adding a polyunsaturated fatty acid oil to the aqueous phase, shear emulsification;

[0009] (3) adding cellulose and its derivatives to the system obtained in step (2), shearing to obtain an emulsion; the content of cellulose and its derivatives in the polyunsaturated fatty acid oil microcapsule is 0.05-0.3wt%;

[0010] The mass fraction of polyunsaturated fatty acid oil in the polyunsaturated fatty acid oil microcapsule is not less than 40%, and the content of fatty acids with a carbon chain length of 20 or more and 4 or more unsaturated double bonds in the polyunsaturated fatty acid oil is not less than 40%.

[0011] The present application can ensure that the high oil microcapsule product obtained is not over-dried, improves the sensory of the product, and ensures the stability of the product during the shelf life by adding a water retention agent to the water-soluble protein wall material, and adding a specific amount of cellulose and its derivatives to the system after emulsification, under the premise of unchanged drying process.

[0012] The application of hydrophilic colloids in the prior art microcapsule system, such as CN101641087B and CN113273635A, although uses hydrophilic colloids, the products are all complex coacervation microcapsule products, the product structure is a multi-layer core-shell structure, the hydrophilic colloid is the main component of the shell layer, and the preparation process needs to be cross-linked by cooling; CN104432059B and CN105707894B add colloids for different purposes, the former is to improve acid resistance, and the latter is to improve high temperature resistance, but the essence is to cross-link with proteins, starches and other substances, and to have a Maillard reaction; CN108208763A combines small molecule emulsifiers with macromolecular emulsifiers including hydrophilic colloids, and mixes and shears to emulsify with fat-soluble nutrients to improve the stability of such emulsions under acidic conditions. It can be seen that the application and application means of hydrophilic colloids in the prior art are different from those of the present application.

[0013] In the present application, "the content of the fatty acid with carbon chain length of more than 20 and more than 4 unsaturated double bonds in the polyunsaturated fatty acid oil is not less than 40%" specifically refers to the content of the fatty acid with carbon chain length of more than 20 and more than 4 unsaturated double bonds in the polyunsaturated fatty acid oil is not less than 50wt%. In the present application, the polyunsaturated fatty acid oil includes but is not limited to one or more of DHA, DPA, EPA, ARA, etc. For example, the DHA oil mentioned in the present application contains DHA, DPA, EPA, ARA, etc. in addition to DHA, but the main component is DHA. In a preferred embodiment of the present application, the content of the polyunsaturated fatty acid oil in the high-load polyunsaturated fatty acid oil microcapsule is 40-55wt%.

[0014] In a preferred embodiment of the present application, in step (1), the moisture retention agent is a phosphate, including but not limited to one or more of disodium hydrogen phosphate, sodium dihydrogen phosphate, sodium tripolyphosphate, and trisodium phosphate. Preferably, it is sodium dihydrogen phosphate. In a preferred embodiment of the present application, the amount of the moisture retention agent added is preferably such that the content of the moisture retention agent in the polyunsaturated fatty acid oil microcapsule is 0.1-0.4wt%. The selected moisture retention agent in the present application is not neutral, and can be used in combination with a pH adjuster as needed to achieve the target environment of the slurry, i.e. a pH adjuster can be added as needed in step (1) of the present application.

[0015] In the specific embodiment of the present application, the content of the water-soluble protein (i.e. water-soluble protein wall material) in the polyunsaturated fatty acid oil microcapsule is 6-20wt%. Among them, the water-soluble protein is one or more of sodium caseinate, whey protein, soy protein, and pea protein. The water-soluble protein wall material used in the preferred embodiment of the present application includes sodium caseinate and / or whey protein, which plays an emulsifying role in the system. When the water-soluble protein wall material contains sodium caseinate, the amount of sodium caseinate added is preferably such that the content of sodium caseinate in the polyunsaturated fatty acid oil microcapsule is 6-16wt%. When the water-soluble protein wall material contains whey protein, the amount of whey protein added is preferably such that the content of whey protein in the polyunsaturated fatty acid oil microcapsule is 4-14wt%. In an alternative embodiment, the water-soluble protein wall material can also include sodium caseinate and whey protein, and the respective amounts of addition can be the above-mentioned preferred amounts of addition.

[0016] In a preferred embodiment of the present application, a bulking agent and / or an antioxidant can also be added to the aqueous phase in step (1), and the order of addition is preferably after the addition of the water retention agent. The antioxidant of the present application includes, but is not limited to, one or more of sodium ascorbate, ascorbic acid, ascorbyl palmitate, vitamin E, and phospholipids. In a specific embodiment of the present application, the antioxidant is added in an amount such that the content of the antioxidant in the polyunsaturated fatty acid oil microcapsule is 3-6 wt%. The bulking agent of the present application can include, but is not limited to, body corn syrup and / or maltodextrin. The bulking agent is added in an amount such that the bulking agent is the remainder after the addition of other ingredients. The ingredients listed in the present application are all more in line with the standards for infant formula, but the actual selection can be made according to the characteristics of the formula.

[0017] In a specific embodiment of the present application, the shearing in step (2) is generally uniform. The shearing conditions can specifically include a shearing speed of 10,000 r / min and a shearing time of 5-20 min.

[0018] In a preferred embodiment of the present application, in step (3), the cellulose and its derivatives include, but are not limited to, one or more of sodium hydroxymethyl cellulose, sodium carboxymethyl cellulose, and sodium hydroxypropyl cellulose. The selection of the derivatives is for the purpose of ensuring that they are easily soluble in the emulsion, and is not specially limited. The selection of the cellulose and its derivatives in the present application is in coordination with other components in the present application, which can reduce the influence of the differences of other components on the product on the basis of improving the water retention capacity of the product, and obtain a product with better stability and improved sensory.

[0019] In a specific embodiment of the present application, the preparation method further comprises the following steps: homogenizing the emulsion obtained in step (3) and spray drying, and adding an anti-caking agent and dry mixing.

[0020] In a specific embodiment of the present application, the homogenization conditions are not limited, and can be selected by those skilled in the art, for example, the pressure condition can be 800 bar. At the same time, a continuous or discontinuous system device can also be selected to achieve the homogenization.

[0021] In a preferred embodiment of the present application, the anti-caking agent includes, but is not limited to, one or more of tricalcium phosphate, silicon dioxide, microcrystalline cellulose, and magnesium stearate. The anti-caking agent is preferably added in an amount such that the content of the anti-caking agent in the polyunsaturated fatty acid oil microcapsule is 0.2-1.0 wt%.

[0022] In a preferred embodiment of the present application, the spray drying conditions are preferably an inlet air temperature of 160-180°C and an outlet air temperature of 60-80°C. In some preferred embodiments, the pressure for spray drying is preferably 110-180 bar. Within this pressure range, it is more advantageous for the formation of droplets in the spray drying process in the system of the present application.

[0023] The high oil loading fat microcapsule product obtained by the preparation method provided by the application is not excessively dried (under the premise that the drying process conditions are conventional), the product sensory is improved, and the stability of the product during the shelf life is ensured.

[0024] Another object of the application is to provide a polyunsaturated fatty acid fat microcapsule obtained by the above preparation method.

[0025] The polyunsaturated fatty acid fat microcapsule provided by the application contains 40-55wt% of polyunsaturated fatty acid fat, the content of fatty acid with a carbon chain number of more than 20 and an unsaturated double bond of more than 4 in the polyunsaturated fatty acid fat is not less than 50wt%, the content of sodium caseinate is 6-16wt% and / or the content of whey protein is 4-14wt% (i.e. the content of sodium caseinate is 6-16wt%, or the content of whey protein is 4-14wt%, or the content of sodium caseinate is 6-16wt% and the content of whey protein is 4-14wt%), the content of cellulose and its derivatives is 0.05-0.3wt%, the content of moisture retention agent is 0.1-0.4wt%, and the content of water is 2-4wt%. That is, the application further provides a high oil loading polyunsaturated fatty acid fat microcapsule with the above characteristics.

[0026] The application solves the problem of excessive drying of the polyunsaturated fatty acid fat microcapsule with a high oil loading rate (the content of polyunsaturated fatty acid fat is not less than 40wt%) during preparation, especially the microcapsule prepared by using a water-soluble protein wall material. The high oil loading microcapsule product obtained by the preparation method provided by the application has good product sensory, and the water content is preferably 2-4wt%. The product has good stability during the shelf life. DETAILED DESCRIPTION

[0027] The specific embodiments of the application will be further described in detail below in combination with examples. The following examples are used to illustrate the application, but are not used to limit the scope of the application.

[0028] Except for Comparative Example 7, the ingredient contents of the microcapsules obtained in the examples and comparative examples are shown in Table 1 below. The preparation method of the polyunsaturated fatty acid fat microcapsule provided by the examples and comparative examples of the application includes the following steps (the system listed in the examples does not need to be intentionally adjusted in pH):

[0029] a. Dissolve the water-soluble wall material in water according to the ratio, add the moisture retention agent, and fully stir;

[0030] b. 10 min, add the filling material and antioxidant, fully stir and dissolve to obtain the water phase;

[0031] c. Add the polyunsaturated fatty acid oil to the above water phase, shear at 10000 r / min for 10 min;

[0032] d. Finally add the cellulose and its derivatives, shear for 2 min, to obtain the emulsion, wherein the solid content is 40%;

[0033] e. The above emulsion is homogenized by a high-pressure homogenizer for 2-3 times at 800 bar;

[0034] f. The spray drying conditions are as follows: the inlet air temperature is 170±5°C, the outlet air temperature is 70±5°C, and the spray pressure is 180 bar;

[0035] g. Add the anti-caking agent for dry mixing to obtain.

[0036] Table 1 Content of each component in the microcapsules obtained in the examples and comparative examples

[0037]

[0038]

[0039] In Table 1, the content in the brackets is the mass content of the substance in the polyunsaturated fatty acid oil microcapsules obtained. “-” indicates that the microcapsules do not contain the component. The DHA oil is derived from algae, wherein the content of DHA is 40%, and the content of the fatty acid with more than 4 unsaturated double bonds including DHA / EPA / DPA / ARA is 60%. In the polyunsaturated fatty acid oil microcapsules obtained by the present application, the content of the components other than water is 100%.

[0040] The ingredients and amounts used in Comparative Example 7 and the preparation method are the same as in Example 1, and the only difference is that the preparation method of the water phase is as follows: the water-soluble wall material, water retention agent, filler, antioxidant, carboxymethyl cellulose and water are mixed according to the ratio, and stirred thoroughly to obtain the water phase. In addition, the only difference between the final product obtained in Comparative Example 7 and Example 1 is the water content, and the content of other components is very close to that in Example 1, and the proportion of water in the two is slightly increased.

[0041] The appearance and performance of the polyunsaturated fatty acid oil microcapsules obtained in the examples and comparative examples are shown in Table 2.

[0042] Table 2 Appearance and performance table of the microcapsules

[0043]

[0044]

[0045] Finally, the method of the present application is only a preferred embodiment, and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a microcapsule of a polyunsaturated fatty acid oil, characterized by, Comprising the following steps: (1) adding a water retention agent to an aqueous solution of water-soluble protein wall material, mixing to obtain an aqueous phase; (2) adding a polyunsaturated fatty acid oil to the aqueous phase, shearing and emulsifying; (3) adding cellulose and its derivatives to the system obtained in step (2), shearing to obtain an emulsion; the content of cellulose and its derivatives in the polyunsaturated fatty acid oil microcapsule is 0.05-0.3wt%; The mass fraction of polyunsaturated fatty acid oil in the polyunsaturated fatty acid oil microcapsule is not less than 40%, and the content of fatty acid with carbon chain length of 20 or more and unsaturated double bond of 4 or more in the polyunsaturated fatty acid oil is not less than 40%; The water retention agent is a phosphate, including but not limited to one or more of disodium hydrogen phosphate, sodium dihydrogen phosphate, sodium tripolyphosphate, and trisodium phosphate; The content of water retention agent in the polyunsaturated fatty acid oil microcapsule is 0.1-0.4wt%; The cellulose and its derivatives include but are not limited to one or more of sodium hydroxymethyl cellulose, sodium carboxymethyl cellulose, and sodium hydroxypropyl cellulose.

2. The production method according to claim 1, characterized by, The water retention agent is sodium dihydrogen phosphate.

3. The production method according to claim 1 or 2, characterized by, The content of water-soluble protein in the polyunsaturated fatty acid oil microcapsule is 6-20wt%, and the water-soluble protein is one or more of sodium caseinate, whey protein, soy protein, and pea protein.

4. The production method according to claim 1 or 2, characterized by, The water-soluble protein wall material includes sodium caseinate and / or whey protein; the content of sodium caseinate in the polyunsaturated fatty acid oil microcapsule is 6-16wt%; the content of whey protein in the polyunsaturated fatty acid oil microcapsule is 4-14wt%.

5. The production method according to claim 1 or 2, characterized by, The aqueous phase also includes a filler and / or an antioxidant; the content of antioxidant in the polyunsaturated fatty acid oil microcapsule is 3-6wt%.

6. The preparation method according to claim 5, characterized in that, The filler includes but is not limited to solid corn syrup and / or malt dextrin; the antioxidant includes but is not limited to one or more of sodium ascorbate, ascorbic acid, ascorbic acid palmitate, vitamin E, and phospholipid.

7. The production method according to claim 1 or 2, characterized by, It also includes the following steps: homogenizing the emulsion and then spray drying, and adding an anti-caking agent for dry mixing.

8. The preparation method according to claim 7, characterized in that, The content of anti-caking agent in the polyunsaturated fatty acid oil microcapsule is 0.2-1.0wt%.

9. The polyunsaturated fatty acid oil microcapsule obtained by the preparation method of any one of claims 1 to 8.

10. A high oil load polyunsaturated fatty acid oil fat microcapsule characterized by, The content of polyunsaturated fatty acid oil in the high-oil polyunsaturated fatty acid oil microcapsule is 40-55wt%, the content of fatty acid with carbon chain length of 20 or more and unsaturated double bond of 4 or more in the polyunsaturated fatty acid oil is not less than 50wt%, the content of sodium caseinate is 6-16wt% and / or the content of whey protein is 4-14wt%, the content of cellulose and its derivatives is 0.05-0.3wt%, the content of water retention agent is 0.1-0.4wt%, and the content of water is 2-4wt%; the water retention agent is a phosphate, including but not limited to one or more of disodium hydrogen phosphate, sodium dihydrogen phosphate, sodium tripolyphosphate, and trisodium phosphate; The preparation method of the high-oil polyunsaturated fatty acid oil microcapsule comprises the following steps: (1) adding a water retention agent to an aqueous solution of water-soluble protein wall material, mixing to obtain an aqueous phase; (2) adding a polyunsaturated fatty acid oil to the aqueous phase, shearing to emulsify; (3) adding cellulose and its derivatives to the system obtained in step (2), shearing to obtain an emulsion; The water-soluble protein wall material comprises sodium caseinate and / or whey protein.

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