Fish oil microcapsule and preparation method thereof

Abstract

The invention discloses fish oil microcapsules and a preparation method thereof. The fish oil microcapsules are composed of the following components in weight: 5-15 parts of fish oil, 6-35 parts of composite wall materials and 0.2-2 parts of emulsifiers, and the water content is 1.5-2.0wt% based on the total mass of the microcapsules; wherein the composite wall materials contain 5-20 parts of rosemary extract. The microcapsules have the advantages of high embedding rate, simple preparation process, strong antioxidant activity and almost no fishy smell.

Description

Technical Field

[0001] The invention belongs to the technical field of microcapsules, and in particular relates to fish oil microcapsules and a preparation method thereof. Background Art

[0002] Fish oil has a variety of biologically active functions, such as lowering blood lipids, scavenging free radicals, nourishing the brain, regulating the immune system, and preventing cardiovascular diseases, which makes it have great development prospects in the food and pet food industries. However, the unique fishy smell of fish oil and its easy oxidation under the action of light and heat limit its development in the food industry. Edible fish oil in the market is usually encapsulated in soft capsules, but the soft capsule particles are large and have a strong fishy smell, which affects the sensory experience of consumers. Moreover, the soft capsule encapsulation has a low degree of protection for fish oil, which is easy to cause rapid oxidation of the product.

[0003] Microencapsulation can improve the adverse properties of fish oil and expand its application in the food industry. Microencapsulation technology is a technology that uses natural or synthetic polymer materials to encapsulate dispersed substances to form tiny particles with semipermeable or sealed capsules. Microencapsulation methods are divided into spray drying, extrusion and coagulation, among which spray drying is widely used due to its low cost, uniform dispersion of core materials and easy industrial production. The encapsulation wall materials used in fish oil microcapsules are mainly natural macromolecules, such as polysaccharides, proteins, etc., but these wall materials have the disadvantages of poor mechanical properties and temperature and moisture resistance, and are easy to break when drying, resulting in a decrease in the encapsulation rate. China's invention patent application publication CN111011594A discloses a fish oil microcapsule and a preparation method thereof, wherein the fish oil microcapsule is composed of 10-40 parts of fish oil, 0-1 part of natural vitamin E, 0-1 part of rosemary extract, 1-5 parts of gum arabic, 1-50 parts of sodium octenyl succinate starch, 1-50 parts of soy protein isolate, 1-10 parts of sodium caseinate, 0-3 parts of monoglyceride, 0-3 parts of sucrose fatty acid ester, 10-30 parts of chicken liver powder, 1-10 parts of yeast extract, and 300-500 parts of purified water, and the final powder is obtained by spray drying technology. This technical solution does not disclose the embedding rate, antioxidant performance and water content, and the composition is complex. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a fish oil microcapsule and a preparation method thereof. The fish oil microcapsule uses rosemary extract as a main wall material and acts as an antioxidant and deodorant, and has the advantages of high encapsulation rate, simple preparation process, strong antioxidant activity and almost no fishy smell.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] A fish oil microcapsule, which consists of the following components in parts by weight and water: 5-15 parts of fish oil, 6-35 parts of composite wall materials and 0.2-2 parts of emulsifiers, with the water content being 1.5-2.0wt% based on the total mass of the microcapsule; wherein the composite wall material contains 5-20 parts of rosemary extract.

[0007] Preferably, the composite wall material is composed of rosemary extract and polysaccharide colloid, and the polysaccharide colloid is 1-15 parts by weight. The polysaccharide colloid is in a suspended state in water and is easy to disperse.

[0008] Preferably, the colloid is one or more of gum arabic, gelatin, pectin and guar gum;

[0009] Preferably, the emulsifier is one or more of sucrose fatty acid esters, monoglycerol fatty acid glycerides, polyglycerol esters, diacetyl tartaric acid monoglyceride and lecithin;

[0010] Preferably, the embedding rate of the fish oil microcapsules is 85-94%.

[0011] Preferably, in order to balance the shelf life of the fish oil microcapsules and the surface smoothness of the microcapsules, the water content is 1.70-1.95 wt % based on the total mass of the microcapsules. Too much water is not conducive to storage, and too little water will easily cause the surface of the microcapsules to crack.

[0012] The present invention also discloses a method for preparing the fish oil microcapsules, comprising the steps of:

[0013] Step 1: adding the composite wall material to 55-80 parts by weight of distilled water, and then heating and stirring to obtain a composite wall material suspension;

[0014] Step 2: adding an emulsifier to the composite wall material suspension and stirring evenly;

[0015] Step 3: adding fish oil to the solution obtained in step 2, and then homogenizing to obtain a raw material liquid. Homogenization is to ultrafine the solid particles in the emulsion by impact and shearing, and spray drying the raw material liquid to obtain fish oil microcapsules.

[0016] Preferably, in order to better dissolve the polysaccharide colloid in the wall material, the heating temperature in step 1 is 35-50° C. and the heating time is 10-40 minutes.

[0017] Preferably, in order to balance the stability of the emulsion and the particle size of the solid particles, the homogenization condition in step 3 is 3000-10000 r / min, and the homogenization time is 2-20 min.

[0018] Preferably, the flow rate of spray drying is 5-20mL / min, the inlet air temperature is 120-150°C, the outlet temperature is 80-120°C, and the spray pressure is 130-180kPa (absolute pressure). Too high an inlet air temperature will cause cracking on the surface of the product particles, resulting in a decrease in yield. Too low an inlet air temperature will result in a high moisture content in the product, severe wall sticking during spray drying, and too much moisture is not conducive to the preservation of the product. Lowering the inlet air temperature can prevent the volatilization of the core material and maintain the integrity of the particle structure.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1) The microcapsule of the present invention uses rosemary extract as the main wall material, and serves as an antioxidant and a deodorant, having three functions in one, and has the advantages of simple ingredients, high embedding rate, strong antioxidant activity and almost no fishy smell.

[0021] 2) The microcapsule preparation method of the present invention is a conventional spray drying method, which has simple process and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a graph showing the scoring results of the sensory experiment. DETAILED DESCRIPTION

[0023] The present invention is further described below. The rosemary extract selected in the embodiment is a powder containing 5 wt% rosmarinic acid. The rosemary extract, colloid and emulsifier selected in the embodiment can be purchased through commercial channels. The spray pressure in the embodiment is an absolute pressure.

[0024] Example 1

[0025] Take 12g of rosemary extract and 5g of gum arabic and add them to 72mL of distilled water, heat in a 40℃ water bath for 15 minutes, stir evenly, and obtain a composite wall material suspension. Add 1g of monoglycerol fatty acid glyceride to the composite wall material suspension and stir evenly, then add 10g of fish oil to the above solution. Use a high-speed disperser to homogenize at 5000r / min for 15 minutes to obtain a raw material solution. Spray dry the raw material solution to obtain fish oil microcapsules. The conditions for spray drying are: sample flow rate 5mL / min, inlet air temperature 130℃, outlet temperature 90℃, and spray pressure 135kPa.

[0026] Comparative Example 1

[0027] Take 17g of gum arabic and add it to 72mL of distilled water, heat it in a 40℃ water bath for 15 minutes, stir it evenly, and get a composite wall material suspension. Add 1g of monoglycerol fatty acid glyceride to the composite wall material suspension and stir it evenly, then add 10g of fish oil to the above solution. Use a high-speed disperser to homogenize at 5000r / min for 15 minutes to get a raw material solution. Spray dry the raw material solution to get fish oil microcapsules. The spray drying conditions are: sample flow rate 5mL / min, inlet air temperature 130℃, outlet temperature 90℃, spray pressure 135kPa.

[0028] Example 2

[0029] Take 15g of rosemary extract and 8g of gum arabic and add them to 64.5mL of distilled water, heat in a 43℃ water bath for 12 minutes, stir evenly, and obtain a composite wall material suspension. Add 0.5g of monoglycerol fatty acid glyceride to the composite wall material suspension and stir evenly, then add 12g of fish oil to the above solution. Use a high-speed disperser to homogenize at 8000r / min for 8 minutes to obtain a raw material solution. Spray dry the raw material solution to obtain fish oil microcapsules. The spray drying conditions are: sample flow rate 5mL / min, inlet air temperature 140℃, outlet temperature 115℃, and spray pressure 135kPa.

[0030] Comparative Example 2

[0031] Take 4g of rosemary extract and 8g of gum arabic and add them to 75.5mL of distilled water, heat in a 43℃ water bath for 12 minutes, stir evenly, and obtain a composite wall material suspension. Add 0.5g of monoglycerol fatty acid glyceride to the composite wall material suspension and stir evenly, then add 12g of fish oil to the above solution. Use a high-speed disperser to homogenize at 8000r / min for 8 minutes to obtain a raw material solution. Spray dry the raw material solution to obtain fish oil microcapsules. The spray drying conditions are: sample flow rate 5mL / min, inlet air temperature 140℃, outlet temperature 115℃, and spray pressure 135kPa.

[0032] Example 3

[0033] Take 18g of rosemary extract and 5g of gum arabic and add them to 66.4mL of distilled water, heat in a 45℃ water bath for 8 minutes, stir evenly to obtain a composite wall material suspension. Add 0.6g of monoglycerol fatty acid glyceride to the composite wall material suspension and stir evenly, then add 10g of fish oil to the above solution. Use a high-speed disperser to homogenize at 9000r / min for 6 minutes to obtain a raw material solution. Spray dry the raw material solution to obtain fish oil microcapsules. The spray drying conditions are: sample flow rate 5mL / min, inlet air temperature 135℃, outlet temperature 100℃, and spray pressure 135kPa.

[0034] Comparative Example 3

[0035] Take 18g of rosemary extract and 5g of gum arabic and add them to 58.4mL of distilled water, heat in a 45℃ water bath for 8 minutes, stir evenly to obtain a composite wall material suspension. Add 0.6g of monoglycerol fatty acid glyceride to the composite wall material suspension and stir evenly, then add 18g of fish oil to the above solution. Use a high-speed disperser to homogenize at 9000r / min for 6 minutes to obtain a raw material solution. Spray dry the raw material solution to obtain fish oil microcapsules. The spray drying conditions are: sample flow rate 5mL / min, inlet air temperature 135℃, outlet temperature 100℃, and spray pressure 135kPa.

[0036] Example 4

[0037] Take 5g of rosemary extract and 15g of gum arabic and add them to 74mL of distilled water, heat in a 48℃ water bath for 7 minutes, stir evenly to obtain a composite wall material suspension. Add 1g of monoglycerol fatty acid glyceride to the composite wall material suspension and stir evenly, then add 5g of fish oil to the above solution. Use a high-speed disperser to homogenize at 6500r / min for 12 minutes to obtain a raw material solution. Spray dry the raw material solution to obtain fish oil microcapsules. The spray drying conditions are: sample flow rate 5mL / min, inlet air temperature 130℃, outlet temperature 105℃, and spray pressure 135kPa.

[0038] Comparative Example 4

[0039] Take 15g of gum arabic and add it to 74mL of distilled water, heat it in a 48℃ water bath for 7 minutes, stir evenly to obtain a composite wall material suspension. Add 1g of monoglycerol fatty acid glyceride to the composite wall material suspension and stir evenly, then add 5g of fish oil and 5g of rosemary extract to the above solution. Use a high-speed disperser to homogenize at 6500r / min for 12 minutes to obtain a raw material solution. Spray dry the raw material solution to obtain fish oil microcapsules. The spray drying conditions are: sample flow rate 5mL / min, inlet air temperature of 130℃, outlet temperature of 105℃, and spray pressure of 135kPa. Note: In this comparative example, 10g of fish oil and 5g of rosemary extract are used as core materials, and rosemary extract is also used as an antioxidant and deodorizer.

[0040] Example 5

[0041] Take 5g of rosemary extract and 10g of gum arabic and add them to 79.5mL of distilled water, heat in a 48℃ water bath for 7 minutes, stir evenly to obtain a composite wall material suspension. Add 0.5g of monoglycerol fatty acid glyceride to the composite wall material suspension and stir evenly, then add 5g of fish oil to the above solution. Use a high-speed disperser to homogenize at 6500r / min for 12 minutes to obtain a raw material solution. Spray dry the raw material solution to obtain fish oil microcapsules. The spray drying conditions are: sample flow rate 5mL / min, inlet air temperature 130℃, outlet temperature 105℃, and spray pressure 135kPa.

[0042] Comparative Example 5

[0043] Take 5g of rosemary extract and 3g of gum arabic and add them to 86.5mL of distilled water, heat in a 48℃ water bath for 7 minutes, stir evenly to obtain a composite wall material suspension. Add 0.5g of monoglycerol fatty acid glyceride to the composite wall material suspension and stir evenly, then add 5g of fish oil to the above solution. Use a high-speed disperser to homogenize at 6500r / min for 12 minutes to obtain a raw material solution. Spray dry the raw material solution to obtain fish oil microcapsules. The spray drying conditions are: sample flow rate 5mL / min, inlet air temperature 130℃, outlet temperature 105℃, and spray pressure 135kPa.

[0044] Characterization experiments

[0045] Experiment 1: Determination of product embedding rate

[0046] Product embedding rate (%) = 1-(surface oil content / product oil content) × 100%.

[0047] 1. Determination of surface oil content

[0048] Accurately weigh 0.5g of microcapsule sample, add 30mL of petroleum ether, extract for 5min, and filter with filter paper. Add 30mL of petroleum ether for washing and filtration, transfer all filtrates to a round-bottom flask that has been dried to a constant mass, heat in a 65℃ water bath to evaporate the petroleum ether, and then dry in a 110℃ oven to a constant weight, weigh, and obtain the surface oil weight. Perform three parallel tests.

[0049] Surface oil content (%) = (surface oil weight / sample weight) × 100%.

[0050] 2. Determination of product oil content

[0051] Accurately weigh 0.5g of the microcapsule product, add 10mL of distilled water, add 90mL of petroleum ether after the sample is completely dissolved, ultrasonically crush the microcapsules (process parameters: 20kHz, power 300W) for 15 minutes, let stand for stratification, and transfer the upper layer liquid into a weighed beaker; repeat the above extraction three times (replace the microcapsule product with the precipitate obtained by standing for stratification, repeat the above adding distilled water, adding petroleum ether, ultrasonically crushing, standing for stratification; the number of repetitions is 2 times), and combine the extracts. Heat the extract in a 65℃ water bath to evaporate the petroleum ether, and then dry it in a 100℃ oven to constant weight, weigh it, and obtain the product oil weight.

[0052] Product oil content (100%) = (product oil weight / sample weight) × 100%.

[0053] Experiment 2: Determination of product moisture content

[0054] The sample was dried in a vacuum drying oven at 70°C to constant weight, and the moisture content was calculated from the mass before and after drying.

[0055] Experiment 3: Determination of product oxidation stability

[0056] The oxidation curve of fish oil and fish oil microcapsules was obtained by OXITEST oxidation stability analyzer. IP refers to the induction period, which is the time required to reach the starting point of oxidation, corresponding to the detectable rancidity or sudden change in oxidation rate. The longer the induction period, the higher the antioxidant activity of the sample. Test conditions: 80℃, oxygen: 5bar.

[0057] Experiment 4: Product sensory evaluation

[0058] Four portions of the same 200 mL freshly squeezed apple juice were taken, no substance was added to the first portion, 0.2 g of fish oil was added to the second portion, 0.22 g of the fish oil microcapsules in Example 1 of the present invention was added to the third portion, and 0.44 g of the fish oil microcapsules in Comparative Example 1 of the present invention was added to the fourth portion. The quality of the four portions of apple juice was evaluated by sensory test.

[0059] Note: The second, third and fourth servings of apple juice contain the same amount of fish oil equivalent, which is 0.2g.

[0060] The characterization experimental data are shown in Tables 1, 2 and Figure 1 .

[0061] Table 1. Performance parameters of fish oil microcapsules in the examples

[0062] project Example 1 Example 2 Example 3 Example 4 Example 5 Embedding rate (%) 91.51 92.82 90.66 88.12 89.7 Water content (wt%) 1.80 1.84 1.75 1.89 1.91 IP(h:min) 12：21 11：55 12：25 11：38 11：58

[0063] Table 2. Performance parameters of comparative fish oil microcapsules

[0064] project Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Control group Embedding rate (%) 45.21 50.13 40.16 46.39 43.00 / Water content (wt%) 1.99 2.12 2.00 2.10 2.21 / IP(h:min) 5：42 6：03 5：58 8：02 5：11 3：02

[0065] Note: The control group in the table is fish oil monomer without microcapsules

[0066] In the fish oil microcapsule experiment of Comparative Example 1, rosemary extract was not added, and the obtained embedding rate and induction period were significantly lower than those of Examples 1-4 of the present invention, and the water content of the obtained fish oil microcapsules was higher than that of Examples 1-4. This indicates that rosemary extract is a good wall material for fish oil microcapsules and can effectively prevent oxidation during the fish oil microcapsule process.

[0067] The ratio of rosemary extract in Comparative Example 2 is lower than the range value, so that the embedding rate and induction period of the fish oil microcapsules obtained in Comparative Example 2 are significantly lower than those in Example 2, indicating that when the content of rosemary extract as the wall material is too low, it is not conducive to the formation and preservation of microcapsules.

[0068] The embedding rate and induction period of the fish oil microcapsules obtained in Comparative Example 3 were significantly lower than those in Examples 1-4, and the water content was higher than that in Examples 1-4, indicating that exceeding a certain proportion of fish oil in the formula would lead to a decrease in the embedding rate, which is not conducive to the preservation of the product.

[0069] Comparative Example 4 uses fish oil and rosemary extract as the wall core, and rosemary extract is also used as an antioxidant. The embedding rate and induction period of Comparative Example 4 are significantly lower than those of Example 4 of the present invention, indicating that rosemary extract is a good wall material for fish oil microcapsules. The IP (h:min) value of Comparative Example 4 is significantly higher than that of Comparative Examples 1-3 and significantly lower than that of Examples 1-4, indicating that rosemary extract can inhibit the oxidation of fish oil microcapsules, indicating that the antioxidant effect of rosemary extract as a wall material on fish oil microcapsules is better than that of rosemary extract as a wall core.

[0070] The proportion of water in Comparative Example 5 exceeds the range value, so that the embedding rate and induction period of the fish oil microcapsules obtained in Comparative Example 5 are significantly lower than those in Example 5, indicating that too much water is not conducive to the preservation of the product.

[0071] Depend on Figure 1It can be seen that there is no significant difference in taste, aroma and overall acceptance between apple juice and fish oil microcapsules with rosemary extract as wall material (fish oil microcapsules in Example 1). The evaluation of fish oil microcapsules without rosemary extract as wall material (comparative example 1 fish oil microcapsules) is obviously lower than that of the embodiments of the present invention. The apple juice containing untreated fish oil has the lowest evaluation. Therefore, untreated fish oil is obviously difficult to accept in terms of sensory perception. However, apple juice containing fish oil microcapsule particles with rosemary extract as wall material has a significant improvement over untreated apple juice. In terms of smell, apple juice containing fish oil microcapsules with rosemary extract as wall material is the most popular, which shows that fish oil microcapsule particles with rosemary extract as wall material not only overcome the fishy smell of fish oil, but also give apple juice a special flavor that is acceptable to people. In terms of overall acceptance, the evaluation of apple juice with fish oil microcapsules with rosemary extract as wall material is not much different from that of apple juice without fish oil. Therefore, apple juice with fish oil microcapsule particles with rosemary extract as wall material can be accepted by the public.

[0072] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Fish oil microcapsules, characterized in that: The microcapsules are made of the following components in parts by weight and distilled water: 5-15 parts of fish oil, 0.2-2 parts of composite wall materials and emulsifiers, and the water content is 1.5-2.0wt% based on the total mass of the microcapsules; wherein the composite wall material is composed of rosemary extract and gum arabic, the composite wall material contains 5-15 parts of rosemary extract and 5 parts of gum arabic, and the embedding rate of the fish oil microcapsules is 85-94%.

2. The fish oil microcapsule according to claim 1, characterized in that The emulsifier is one or more of sucrose fatty acid ester, monoglycerol fatty acid glyceride, polyglycerol ester, diacetyl tartaric acid monoglyceride and lecithin.

3. The fish oil microcapsule according to claim 1, characterized in that Based on the total mass of the microcapsules, the water content is 1.70-1.95 wt%.

4. A method for preparing fish oil microcapsules according to any one of claims 1 to 3, comprising the following steps: step 1, adding a composite wall material to 55-80 parts by weight of distilled water, then heating and stirring to obtain a composite wall material suspension; step 2, adding an emulsifier to the composite wall material suspension and stirring to obtain a composite wall material suspension; step 3, adding fish oil to the solution obtained in step 2, then homogenizing to obtain a raw material liquid, and spray drying the raw material liquid to obtain fish oil microcapsules.

5. The preparation method according to claim 4, characterized in that: The heating temperature of step 1 is 35-50° C., and the heating time is 10-40 minutes.

6. The preparation method according to claim 4, characterized in that: The homogenization condition in step 3 is 3000-10000r / min, and the homogenization time is 2-20min.

7. The preparation method according to claim 4, characterized in that: The flow rate of spray drying is 5-20 mL / min, the inlet air temperature is 120-150°C, the outlet temperature is 80-120°C, and the spray pressure is an absolute pressure of 130-180 kPa.

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