Water-soluble ginger oleoresin microcapsule, and preparation method therefor and use thereof

Abstract

The present invention relates to the technical field of microencapsulation of natural products, and specifically relates to a water-soluble ginger oleoresin microcapsule, and a preparation method therefor and the use thereof. In the present invention, by using modified starch, plant polysaccharide substances, etc., as wall materials and ginger oleoresin as the core material, a ginger oleoresin microcapsule product is obtained by means of the processes of molecular coating of the ginger oleoresin, emulsification, high-pressure homogenization, leaving to stand at a constant temperature, drying, etc. The product has the characteristics of a high gingerol content, good water solubility, and low spiciness in the form of a solution; moreover, the product has good stability in an acid solution environment, can meet the requirements of high stability, no precipitation, low spiciness and good thermal sensation in a low-pH environment, and is applicable to the fields of food products, beverages, health-care food products, medicines, cosmetics, etc.

Description

A water-soluble ginger oleoresin microcapsule and its preparation method and application Technical Field

[0001] The present invention relates to the technical field of microencapsulation of natural products, and in particular to water-soluble ginger oleoresin microcapsules and a preparation method and application thereof. Background Art

[0002] Ginger, also known as Junjiang (Ginger) or Baijiang (White Ginger), is a perennial herb in the Zingiberaceae family. my country is the birthplace of ginger and one of its major producers. Ginger is widely distributed in my country, with a cultivation history of over 2,000 years. It is rich in nutrients, including gingerol, starch, dietary fiber, protein, fat, and trace elements. It is often used as a seasoning, enhancing flavor and aroma. It is also widely used as a traditional Chinese medicine for the treatment and prevention of various diseases. The Compendium of Materia Medica states that ginger is "hot in nature, pungent in taste, and enters the heart, kidney, spleen, stomach, and lung meridians." It has the effects of warming the middle and dispelling cold, restoring yang, unblocking the meridians, and removing dampness and reducing inflammation. The Shennong's Classic of Materia Medica lists it as a top-grade herb, "used as a vegetable, a herb, a fruit, and a medicine, its benefits are numerous." Ginger is now widely used in food, medicine, health supplements, and cosmetics.

[0003] Gingerol, the general term for the spicy component of ginger, is a yellow to yellowish-brown oily substance that is insoluble in water but soluble in lipophilic solvents such as ethanol, benzene, and ether. It is a mixture of various substances. Its main components include gingerols, shogaols, gingerols, zingerones, zingerones, gingerdiols, gingerdiones, and neogingerols, as well as flavonoids containing 3-methoxy-4-hydroxyphenyl. As the primary active substance in ginger, gingerol has significant antioxidant and anti-inflammatory properties, and exhibits excellent stomachic, hepatoprotective, choleretic, antiemetic, anti-gastric ulcer, anticoagulant, and tumor-suppressing effects. It is widely used in clinical medicine and health foods.

[0004] Ginger oleoresin is a viscous, yellowish-brown to brownish-yellow semi-fluid substance obtained through extraction and concentration from ginger. It has a strong ginger flavor and its main ingredients are fat-soluble substances such as ginger essential oil and gingerol. It is often used in condiments, health foods with antioxidant and anti-inflammatory needs, and pharmaceuticals.

[0005] With economic development, consumers are becoming more aware of their health and demanding more diverse and functional foods, leading to a growing demand for healthy ingredients from natural sources. The market is urgently seeking to develop ginger oleoresin microcapsules using food or other safe, naturally derived ingredients. These microcapsules are characterized by high gingerol content, low pungency, good water solubility, and stability in low-pH environments (e.g., beverages, oral liquids, candies, solid beverages, and cold drinks).

[0006] There are currently relevant literature and patent reports on the research of using ginger to prepare ginger oleoresin microcapsules, such as "The Effect of Spray Drying Conditions on Ginger Oleoresin Microcapsules" ("Food Science" Issue 3, 2009, School of Food Science and Engineering, Yangzhou University), which reported that ginger oleoresin was obtained by ethanol extraction and vacuum drying using ginger as raw material, and ginger oleoresin microcapsules were prepared by emulsification, homogenization and spray drying using β-cyclodextrin and Tween-80 as wall materials. The main focus was on the effects of different spray drying conditions on ginger oil microcapsules. Chinese patent CN 101473954A discloses a ginger oleoresin microcapsule and a preparation method thereof; Chinese patent CN 113424958A discloses a high gingerol content taste-masking microcapsule and a preparation method thereof; Chinese patent CN 113952314A discloses a tea polyphenol-gingerol combination microparticle and a preparation method and application thereof; Chinese patent CN 109511983A discloses a ginger oleoresin microcapsule and a preparation method thereof; Chinese patent CN 102895189A discloses a gingerol liposome and a preparation method thereof, etc. Although the above processes can improve the dissolution effect of ginger oleoresin to a certain extent, most of the processes are relatively complicated. A large amount of chemical synthetic surfactants such as Tween, monoglyceride, sucrose ester, polyethylene glycol, etc. are used in the preparation process, which leads to uncertainty in food safety. In addition, most products have problems such as low gingerol content, strong spiciness, poor water solubility, and low stability in low pH solutions. They cannot meet the needs of food health and safety, as well as the quality requirements of beverages, oral liquids, candies, solid beverages, cold drinks, etc. for ginger oleoresin microcapsule powder with high gingerol content, low spiciness, good water solubility, and stable application in low pH environments. Technical issues

[0007] In order to overcome the deficiencies and shortcomings of the prior art, the primary purpose of the present invention is to provide a method for preparing water-soluble ginger oleoresin microcapsules. The method does not use chemical surfactants and chemical solvents, and uses widely used food raw materials and auxiliary materials. Through the combination of molecular coating, emulsification, homogenization, microcapsule drying and other technologies, a ginger oleoresin microcapsule product with high gingerol content, low spiciness, good thermal sensation, good water solubility and stability in a low pH solution environment is obtained.

[0008] Another object of the present invention is to provide water-soluble ginger oleoresin microcapsules prepared by the above-mentioned preparation method, which have the characteristics of high gingerol content, low spicy taste of aqueous solution, good water solubility, high solution clarity, and good stability in a low pH solution environment, and can meet the special requirements of foods such as beverages, oral liquids, candies, solid beverages and cold drinks, as well as medicines.

[0009] Another object of the present invention is to provide an application of the water-soluble ginger oleoresin microcapsules. Technical Solutions

[0010] The purpose of the present invention is achieved through the following technical solutions:

[0011] A method for preparing water-soluble ginger oleoresin microcapsules comprises the following steps:

[0012] (1) Cyclodextrin is mixed with water and heated until completely dissolved to obtain a cyclodextrin solution; ginger oleoresin is then added under high shear conditions for emulsification and dispersion to obtain a ginger oleoresin-cyclodextrin dispersion;

[0013] (2) mixing the wall material and water to prepare a solution and heating the solution to obtain a wall material solution;

[0014] (3) adding the ginger oleoresin-cyclodextrin dispersion obtained in step (1) to the wall material solution obtained in step (2) under high shear conditions, performing emulsification and dispersion, and adjusting the pH of the system to 6.5-10.0; then adding flavonoids and continuously performing emulsification and dispersion to obtain a ginger oleoresin emulsion; and then high-pressure homogenizing the ginger oleoresin emulsion to obtain a ginger oleoresin homogenate;

[0015] (4) the homogenized ginger oleoresin solution obtained in step (3) is allowed to stand at a constant temperature, and finally dried to obtain water-soluble ginger oleoresin microcapsules;

[0016] The cyclodextrin in step (1) is at least one of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin;

[0017] The mass ratio of ginger oleoresin to cyclodextrin in step (1) is (1-2):1;

[0018] The heating temperature in step (1) is 40°C to 90°C;

[0019] The concentration of the cyclodextrin solution in step (1) is 10-50 wt.%;

[0020] The temperature of the ginger oleoresin in step (1) is 20°C to 80°C, preferably 40°C to 70°C;

[0021] The speed of the emulsification dispersion in step (1) is 500 rpm to 20,000 rpm, preferably 3,000 rpm to 10,000 rpm; the time of the emulsification dispersion is 0.5 min to 60 min, preferably 10 min to 30 min; the temperature of the emulsion dispersion is 40° C. to 90° C.

[0022] The wall material in step (2) is at least one of gum arabic, pullulan, modified starch, gum dawa, peach gum, fucoidan and chitosan;

[0023] The modified starch is preferably at least one of sodium starch octenylsuccinate and hydroxypropyl starch;

[0024] The wall material solution in step (2) preferably further includes a filler;

[0025] The filler is at least one of maltodextrin, microcrystalline cellulose, glucose syrup, microporous starch, resistant dextrin, white sugar, lactitol, erythritol, maltitol, sorbitol, stachyose, beet water-soluble fiber, trehalose, maltooligosaccharide and lactose;

[0026] The concentration of the wall material in the wall material solution is 5 wt.% to 70 wt.%, and the concentration of the filler is 5 wt.% to 70 wt.%;

[0027] The temperature of the wall material solution in step (2) and step (3) is 40°C to 90°C, preferably 40°C to 80°C;

[0028] The mass ratio of the ginger oleoresin-cyclodextrin dispersion and the wall material solution in step (3) is 1:(2.5-3);

[0029] The speed of the emulsification and dispersion in step (3) is 500 rpm to 20,000 rpm, preferably 3,000 rpm to 10,000 rpm; the time of the emulsification and dispersion is 0.5 min to 60 min, preferably 10 min to 30 min; the temperature of the emulsification and dispersion is 40° C. to 90° C., preferably 40° C. to 80° C.;

[0030] The reagent for adjusting the pH of the system in step (3) is at least one of sodium carbonate, sodium bicarbonate, potassium carbonate, sodium hexametaphosphate, sodium tripolyphosphate, sodium polyphosphate, sodium pyrophosphate and sodium citrate;

[0031] The pH of the system described in step (3) is preferably 7.0-9.0;

[0032] The flavonoid substance in step (3) is at least one of EGCG, hesperidin, dihydromyricetin, myricetin, rutin and quercetin, and the addition amount is 0.01 wt.%~1.5 wt.% of the final product;

[0033] The pressure of the high-pressure homogenization in step (3) is 0.1 MPa to 100 MPa, preferably 20 MPa to 90 MPa;

[0034] The number of times of high pressure homogenization in step (3) is 1 to 3 times, preferably 1 to 2 times;

[0035] The constant temperature standing temperature in step (4) is 30°C to 90°C, preferably 40°C to 80°C;

[0036] The constant temperature standing time in step (4) is 1 h to 12 h, preferably 4 h to 8 h;

[0037] The drying in step (4) is centrifugal spray drying, pressure spray drying, freeze drying or hot air drying;

[0038] The drying in step (4) is preferably centrifugal spray drying;

[0039] The air inlet temperature of the centrifugal spray drying is preferably 160°C to 200°C, and the air outlet temperature is preferably 70°C to 100°C;

[0040] A water-soluble ginger oleoresin microcapsule obtained by the above preparation method;

[0041] Application of the water-soluble ginger oleoresin microcapsules in food, medicine or cosmetics;

[0042] The present invention has no particular limitation on the form of the food, which can be added to liquid food or solid food, and is preferably prepared as a beverage.

[0043] If the food is a health food, the present invention has no particular limitation on the dosage form of the health food, and the health food may be in the form of capsules, tablets, oral liquids, and the like.

[0044] Principle of the present invention:

[0045] The cyclodextrin molecule has a slightly conical hollow cylindrical three-dimensional ring structure. In its hollow structure, the outer upper end (larger open end) is composed of secondary hydroxyl groups of C2 and C3, and the lower end (smaller open end) is composed of primary hydroxyl groups of C6, which are hydrophilic. The hollow cavity forms a hydrophobic area due to the shielding effect of the CH bond, showing a certain non-polarity. The hollow structure in the middle of the cyclodextrin molecule can be embedded with other molecules with similar molecular weight. The present invention adopts the cyclodextrin molecule pre-coating technology, and takes advantage of the fact that the gingerol components in the ginger oleoresin are easily embedded in the hollow structure of the cyclodextrin molecule to pre-coat the ginger oleoresin. Under normal circumstances, the molecules embedded in the hollow structure of the cyclodextrin are released again very slowly, thereby achieving the technical effect of reducing the spiciness to a certain extent.

[0046] Due to the solubility defect of poor water solubility in cyclodextrin, if the effective ingredient in the ginger oleoresins such as cyclodextrin chimeric gingerol is fully relied on, the actual pre-coated amount will be not very large, and then the gingerol content in the finished product will be not high. In order to improve the content of gingerol, the ratio of ginger oleoresin will be increased, so that in the process of cyclodextrin pre-coating, a large amount of gingerols are still left in ginger oleoresin-cyclodextrin dispersion and can not be coated by cyclodextrin, and then the product pungent taste is obviously caused, and actual demand cannot be met. In order to solve the above-mentioned technical problems, the present invention is based on the pre-coating of cyclodextrin molecules, further in conjunction with microcapsule embedding technology, adopts modified starch etc. to carry out microcapsule emulsification and secondary embedding, and then can reach the purpose of improving gingerol content, effectively reducing pungent taste, improving water solubility and stability.

[0047] Furthermore, gingerol in ginger oleoresin is easily converted to shogaol (shogaol has a much spicier taste than gingerol) when heated and in a low pH environment. Therefore, during the microencapsulation and secondary encapsulation process, the present invention effectively prevents the conversion of gingerol to shogaol by rationally controlling the pH of the liquid, further increasing the gingerol content while preventing an increase in spiciness. The addition of flavonoids further enhances product stability. Beneficial effects

[0048] The present invention has the following advantages and effects compared to the prior art:

[0049] (1) Compared with the prior art, the present invention adopts a method for preparing water-soluble ginger oil microcapsules with high gingerol content and low spiciness without using surfactants or chemical solvents. No surfactants are used in the preparation process, and the obtained product has high application safety and low cost. No chemical solvents are used in the preparation process, and the production process is safer, which is conducive to the industrial production and scale-up of the product.

[0050] (2) The present invention adopts a combination of cyclodextrin molecule pre-coating and microcapsule embedding technology. By controlling the pH value of the liquid system and through the assistance of flavonoids and other technical means, the embedding amount is increased, the stability of the gingerol component is maintained, and the spiciness is reduced, thereby achieving the technical effects of high gingerol content, high water solubility, low spiciness, and good thermal sensation.

[0051] (3) After the ginger oleoresin emulsion is homogenized, the present invention adopts a constant temperature static fusion method to further strengthen the effective coating of the colloid on the ginger oleoresin, improve the encapsulation rate of the product, and ensure the stability during application.

[0052] (4) The water-soluble ginger oleoresin microcapsules prepared by the present invention have a high gingerol content, wherein the gingerol content in the final product can reach up to 11.7%; the water-soluble ginger oleoresin microcapsules have significantly improved water solubility and good water solubility, and their aqueous solutions are clear and transparent with low spicy taste; in addition, the water-soluble ginger oleoresin microcapsules have the characteristics of good stability in low pH solution environments, are not turbid or precipitate in acidic solutions, have high stability, and significantly improved pH tolerance.

[0053] (5) The water-soluble ginger oleoresin microcapsules prepared by the present invention can meet the special requirements of food (beverages, oral liquids, candies, solid beverages, cold drinks, etc.), medicines and cosmetics, and have broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a diagram showing the dissolution of ginger oleoresin in water.

[0055] FIG2 is a diagram showing the dissolution effect of the water-soluble ginger oleoresin microcapsules prepared in Examples 1 to 3 in a neutral aqueous solution, wherein from left to right are Examples 1 to 3.

[0056] FIG3 is a diagram showing the dissolution effects of the water-soluble ginger oleoresin microcapsules prepared in comparative examples 1 to 5 in a neutral aqueous solution, wherein comparative examples 1 to 5 are shown from left to right.

[0057] FIG4 is a diagram showing the dissolution effect of the water-soluble ginger oleoresin microcapsules prepared in Examples 1 to 3 in an acidic aqueous solution, wherein Examples 1 to 3 are shown from left to right.

[0058] FIG5 is a diagram showing the dissolution effects of the water-soluble ginger oleoresin microcapsules prepared in comparative examples 1 to 5 in an acidic aqueous solution, wherein comparative examples 1 to 5 are shown from left to right.

[0059] FIG6 is a particle size distribution diagram of the water-soluble ginger oleoresin microcapsules prepared in Examples 1 to 3.

[0060] FIG7 is a particle size distribution diagram of the water-soluble ginger oleoresin microcapsules prepared in Comparative Examples 1 to 5. Modes for Carrying Out the Invention

[0061] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0062] Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0063] In this example, ginger oleoresin was purchased from the market and had a gingerol content of 41.6%. Its solubility in neutral aqueous solution is shown in FIG1 .

[0064] Example 1

[0065] (1) Place ginger oleoresin with a gingerol content of 41.6% in a 50°C environment and keep it still; weigh 28g of α-cyclodextrin and 10g of β-cyclodextrin, add them to 52g of deionized water, and heat them in a water bath to 75°C to keep the solution completely dissolved; then add 63g of the above ginger oleoresin under high shear conditions and fully emulsify and disperse it (emulsification dispersion speed of 3000rpm, time of 16min, emulsion temperature of 72°C~78°C) to obtain ginger oleoresin-cyclodextrin dispersion;

[0066] (2) Weigh 60 g of gum arabic, 6 g of gum dawa, 23 g of maltooligosaccharide, and 39 g of maltodextrin, add them to 314 g of deionized water, stir evenly, and obtain a wall material solution with a solid content of 28.9%. Heat the wall material solution in a water bath to 70°C.

[0067] (3) Maintaining the temperature of the wall material solution in step (2), the ginger oleoresin-cyclodextrin dispersion prepared in step (1) was added to the wall material solution under high shear conditions, and fully emulsified and dispersed (emulsified dispersion speed of 4500 rpm, time of 20 min, emulsion temperature of 69°C to 75°C); at the same time, sodium carbonate and sodium hexametaphosphate were added to adjust the pH value of the system to 7.9; then EGCG was added (the addition amount was 0.1% of the final product), and the emulsification and dispersion was continued until it was completely dissolved to form a uniform ginger oleoresin emulsion; the ginger oleoresin emulsion was then subjected to high-pressure homogenization (homogenization pressure of 75 MPa, homogenization 2 times) to obtain a stable ginger oleoresin homogenate;

[0068] (4) The ginger oleoresin homogenate obtained in step (3) was allowed to stand at a constant temperature of 45°C for 5 hours and then spray-dried, wherein the drying air inlet temperature was 170°C to 195°C and the air outlet temperature was 80°C to 95°C, to obtain water-soluble ginger oleoresin microcapsules.

[0069] After testing, the water-soluble ginger oleoresin microcapsules have excellent water solubility, the solution is clear and transparent, the gingerol content is 10.9wt.%, the embedding rate is 97.6%, and the spiciness in the mouth and throat is low.

[0070] Example 2

[0071] (1) Place ginger oleoresin with a gingerol content of 41.6% in a 50°C environment and keep it still; weigh 20g of β-cyclodextrin and 22g of γ-cyclodextrin, add them to 52g of deionized water, heat it to 75°C in a water bath, keep the solution completely dissolved, then add 68g of the above ginger oleoresin under high shear state, and fully emulsify and disperse it (emulsification dispersion speed is 3500rpm, time is 15min, emulsion temperature is 72°C~78°C) to obtain ginger oleoresin-cyclodextrin dispersion;

[0072] (2) Weigh 70 g of sodium starch octenylsuccinate, 20 g of pullulan, 15 g of maltitol, and 40 g of maltodextrin, add them to 315 g of deionized water, stir evenly, and obtain a wall material solution with a solid content of 31.5%. Heat the wall material solution in a water bath to 73 °C.

[0073] (3) Maintaining the temperature of the wall material solution in step (2), the ginger oleoresin-cyclodextrin dispersion prepared in step (1) is added to the wall material solution under high shear conditions, and fully emulsified and dispersed (emulsified dispersion speed is 5000 rpm, time is 15 min, emulsion temperature is 72°C~77°C); at the same time, potassium carbonate and sodium pyrophosphate are added to adjust the pH value of the system to 8.2; then myricetin is added (the addition amount is 0.08% of the final product), and the emulsification and dispersion is continued until it is completely dissolved to form a uniform ginger oleoresin emulsion; the ginger oleoresin emulsion is then subjected to high-pressure homogenization (homogenization pressure is 80 MPa, homogenization is performed twice) to obtain a stable ginger oleoresin homogenate;

[0074] (4) The ginger oleoresin homogenate obtained in step (3) was allowed to stand at a constant temperature of 45°C for 5 hours and then spray-dried, wherein the drying air inlet temperature was 170°C to 195°C and the air outlet temperature was 80°C to 95°C, to obtain water-soluble ginger oleoresin microcapsules.

[0075] After testing, the water-soluble ginger oleoresin microcapsules have excellent water solubility, the solution is clear and transparent, the gingerol content is 10.5wt.%, the embedding rate is 97.3%, and the spiciness in the mouth and throat is low.

[0076] Example 3

[0077] (1) Place ginger oleoresin with a gingerol content of 41.6% in a 55°C environment and keep it still; weigh 22g of α-cyclodextrin and 18g of γ-cyclodextrin, add them to 52g of deionized water, heat it to 75°C in a water bath, keep the solution completely dissolved, then add 78g of the above ginger oleoresin under high shear state, and fully emulsify and disperse it (emulsification dispersion speed is 5500rpm, time is 20min, emulsion temperature is 72°C~78°C) to obtain ginger oleoresin-cyclodextrin dispersion;

[0078] (2) Weigh 50 g of sodium starch octenylsuccinate, 10 g of gum arabic, 10 g of hydroxypropyl starch, 15 g of erythritol, 5 g of resistant dextrin, and 60 g of maltodextrin, add them to 315 g of deionized water, stir evenly, and obtain a wall material solution with a solid content of 32.2%. Heat the wall material solution in a water bath to 80°C.

[0079] (3) Maintaining the temperature of the wall material solution in step (2), the ginger oleoresin-cyclodextrin dispersion prepared in step (1) is added to the wall material solution under high shear conditions, and fully emulsified and dispersed (emulsified dispersion speed is 6000 rpm, time is 18 min, emulsion temperature is 75°C~80°C); at the same time, sodium carbonate and sodium tripolyphosphate are added to adjust the pH value of the system to 8.3; then quercetin (the addition amount is 0.12% of the final product) is added, and emulsification and dispersion are continued until it is completely dissolved to form a uniform ginger oleoresin emulsion; the ginger oleoresin emulsion is then subjected to high-pressure homogenization (homogenization pressure 50 MPa, homogenization 2 times) to obtain a stable ginger oleoresin homogenate;

[0080] (4) The ginger oleoresin homogenate obtained in step (3) was allowed to stand at a constant temperature of 50°C for 5 hours and then spray-dried, with the drying air inlet temperature being 170°C to 195°C and the air outlet temperature being 80°C to 95°C, to obtain water-soluble ginger oleoresin microcapsules.

[0081] After testing, the water-soluble ginger oleoresin microcapsules have excellent water solubility, the solution is clear and transparent, the gingerol content is 11.7wt.%, the embedding rate is 98.3%, and the spiciness in the mouth and throat is low.

[0082] Comparative Example 1 (no cyclodextrin pre-coating, direct microcapsulation with starch or other wall materials)

[0083] (1) Place ginger oleoresin with a gingerol content of 41.6% in a 55°C environment and keep it still;

[0084] (2) The preparation of the wall material solution is the same as in Example 1;

[0085] (3) Maintaining the temperature of the wall material solution in step (2), 63 g of the ginger oleoresin in step (1) was added to the wall material solution under high shear conditions and fully emulsified and dispersed (emulsification and dispersion speed was 4500 rpm, time was 20 min, and emulsion temperature was 69°C to 75°C). At the same time, sodium carbonate and sodium hexametaphosphate were added to adjust the pH value of the system to 7.9; then EGCG was added (the addition amount was 0.1% of the final product) and the emulsification and dispersion was continued until it was completely dissolved to form a ginger oleoresin emulsion; the ginger oleoresin emulsion was then subjected to high-pressure homogenization (homogenization pressure 75 MPa, homogenization 2 times) to obtain a ginger oleoresin homogenate.

[0086] (4) The ginger oleoresin homogenate obtained in step (3) was allowed to stand at a constant temperature of 45°C for 5 hours and then spray-dried, wherein the drying air inlet temperature was 170°C to 195°C and the air outlet temperature was 80°C to 95°C, to obtain water-soluble ginger oleoresin microcapsules.

[0087] After testing, the water-soluble ginger oleoresin microcapsules were found to have general water solubility, a relatively turbid solution, a gingerol content of 9.1 wt.%, an encapsulation rate of 75.7%, a low oral spicy taste, and a high pharyngeal spicy taste.

[0088] Comparative Example 2 (no myricetin added)

[0089] (1) The preparation of ginger oleoresin-cyclodextrin dispersion was the same as in Example 2;

[0090] (2) The preparation of the wall material solution is the same as in Example 2;

[0091] (3) maintaining the temperature of the wall material solution in step (2), adding the ginger oleoresin-cyclodextrin dispersion obtained in step (1) to the wall material solution under high shear conditions, and fully performing emulsification and dispersion (emulsification and dispersion speed of 5000 rpm, time of 15 min, emulsion temperature of 72°C to 77°C); at the same time, adding potassium carbonate and sodium pyrophosphate to adjust the pH value of the system to 8.2 to obtain a ginger oleoresin emulsion; and then high-pressure homogenizing the ginger oleoresin emulsion (homogenization pressure of 80 MPa, homogenization 2 times) to obtain a ginger oleoresin homogenate;

[0092] (4) The ginger oleoresin homogenate obtained in step (3) was allowed to stand at a constant temperature of 45°C for 5 hours and then spray-dried, wherein the drying air inlet temperature was 170°C to 195°C and the air outlet temperature was 80°C to 95°C, to obtain water-soluble ginger oleoresin microcapsules.

[0093] Testing showed that the water-soluble ginger oleoresin microcapsules had excellent water solubility, the solution was clear and transparent, the gingerol content was 8.7 wt.%, the encapsulation rate was 81.6%, the oral spiciness was low, and the pharyngeal spiciness was moderate.

[0094] Comparative Example 3 (pH value of the emulsion was not adjusted to 8.2)

[0095] (1) The preparation of ginger oleoresin-cyclodextrin dispersion was the same as in Example 2;

[0096] (2) The preparation of the wall material solution is the same as in Example 2;

[0097] (3) maintaining the temperature of the wall material solution in step (2), adding the ginger oleoresin-cyclodextrin dispersion obtained in step (1) to the wall material solution under high shear conditions, and fully emulsifying and dispersing the ginger oleoresin (emulsifying and dispersing speed is 5000 rpm, time is 15 min, emulsion temperature is 72°C~77°C); then adding myricetin (addition amount is 0.08% of the final product), and continuously emulsifying and dispersing the ginger oleoresin until it is completely dissolved to form a ginger oleoresin emulsion; then high-pressure homogenizing the ginger oleoresin emulsion (homogenizing pressure is 80 MPa, homogenizing twice) to obtain a ginger oleoresin homogenate;

[0098] (4) The ginger oleoresin homogenate obtained in step (3) was allowed to stand at a constant temperature of 45°C for 5 hours and then spray-dried, wherein the drying air inlet temperature was 170°C to 195°C and the air outlet temperature was 80°C to 95°C, to obtain water-soluble ginger oleoresin microcapsules.

[0099] After testing, the water-soluble ginger oleoresin microcapsules were found to have general water solubility, turbid solution, gingerol content of 8.8 wt.%, encapsulation rate of 79.2%, high oral spicy taste, and high pharyngeal spicy taste.

[0100] Comparative Example 4 (direct drying without constant temperature static fusion)

[0101] (1) The preparation of ginger oleoresin-cyclodextrin dispersion was the same as in Example 3;

[0102] (2) The preparation of the wall material solution is the same as in Example 3;

[0103] (3) The preparation of ginger oleoresin homogenate was the same as in Example 3;

[0104] (4) The ginger oleoresin homogenate obtained in step (3) is directly spray-dried, wherein the drying air inlet temperature is 170°C to 195°C and the air outlet temperature is 80°C to 95°C, to obtain water-soluble ginger oleoresin microcapsules.

[0105] Testing showed that the water-soluble ginger oleoresin microcapsules had excellent water solubility, the solution was clear and transparent, the gingerol content was 9.8 wt.%, the encapsulation rate was 88.3%, the oral spiciness was moderate, and the pharyngeal spiciness was moderate.

[0106] Comparative Example 5 (using cyclodextrin alone for coating without using microencapsulation technology)

[0107] (1) Place ginger oleoresin with a gingerol content of 41.6% in a 50°C environment and keep it still; weigh 38g of α-cyclodextrin and 26g of β-cyclodextrin, add them to 366g of deionized water, and heat them in a water bath to 75°C to keep the solution completely dissolved; then add 63g of the above ginger oleoresin under high shear conditions and fully emulsify and disperse it (emulsification dispersion speed of 3000rpm, time of 16min, emulsion temperature of 72°C~78°C) to obtain ginger oleoresin-cyclodextrin dispersion;

[0108] (2) The ginger oleoresin-cyclodextrin dispersion is then subjected to high-pressure homogenization (homogenization pressure 75 MPa, homogenization 2 times) to obtain a ginger oleoresin homogenate;

[0109] (3) The ginger oleoresin homogenate obtained in step (2) was allowed to stand at a constant temperature of 45°C for 5 hours and then spray-dried (Note: after standing at a constant temperature for 5 hours, there was obvious "ginger oleoresin" floating on the upper part of the emulsion, and there was a small amount of sediment at the bottom of the emulsion). The liquid at the bottom of the emulsion was filtered through a 100-mesh filter to remove the sediment, and the filtrate was dried. The drying air inlet temperature was 170°C to 195°C, and the air outlet temperature was 80°C to 95°C to obtain water-soluble ginger oleoresin microcapsules.

[0110] After testing, the water-soluble ginger oleoresin microcapsules were found to have general water solubility, turbid solution, gingerol content of 6.1 wt.%, encapsulation rate of 33.6%, high spicy taste in the mouth and throat.

[0111] Effect embodiment

[0112] (1) Determination of embedding rate

[0113] ① Determination of gingerol content in microcapsules: Accurately weigh 5 g of water-soluble ginger oleoresin microcapsules and add 15 mL of water to form a homogenous system. Centrifuge at 4000 rpm for 30 min. Discard the supernatant and tilt the centrifuge bucket for a while to remove surface moisture from the bottom of the bucket. Then, add 35 mL of anhydrous ethanol to dissolve the ginger oil. Determine the gingerol content by spectrophotometry at 280 nm.

[0114] ② Determination of gingerol content on the microcapsule surface: Accurately weigh 5 g of water-soluble ginger oleoresin microcapsules, add 25 mL of anhydrous ethanol, and stir on a blender for 5 minutes. Filter the mixture through filter paper, rinse the microcapsules on the filter paper with anhydrous ethanol to remove the surface gingerol, and dilute to 50 mL. Determine the gingerol content by spectrophotometry at 280 nm.

[0115] ③ Calculation of embedding efficiency: embedding efficiency (%) = (1-gingerol content on the microcapsule surface) * 100 / gingerol content in the microcapsule.

[0116] (2) Spiciness measurement

[0117] The water-soluble ginger oleoresin microcapsule samples prepared in Examples 1-3 and Comparative Examples 1-5 were numbered 1-8. Ginger oleoresin solutions of the same concentration (0.2 wt.%) were prepared using purified water. Eighteen randomly selected participants tasted each of the eight solutions in turn and evaluated their oral and throat spiciness, choosing between high, medium, and low. The spiciness rating was calculated based on the combined evaluations of all 18 participants. (Boiled water was used to rinse the mouth between tastings to avoid any influence from the previous solution.)

[0118] (3) Content of microcapsule gingerol

[0119] Weigh an appropriate amount of water-soluble ginger oleoresin microcapsules and sonicate in 15 mL of water for 10 minutes to completely dissolve. Transfer the sample to a 50 mL volumetric flask and dilute to the mark with methanol to prepare the sample solution. The standard solution preparation and specific assay methods refer to the national standard "GB / T 22293-2008 HPLC method for the determination of the main irritant components of ginger and its oleoresin."

[0120] (4) Determination of microcapsule particle size

[0121] The particle size of microcapsules was determined using GB / T 19077-2016 Particle size distribution laser diffraction method.

[0122] (5) Solubility test and stability evaluation method in low pH solution environment

[0123] Accurately weigh 0.1500 g of water-soluble ginger oleoresin microcapsule sample, add a small amount of distilled water or acidic water (0.5 g citric acid and 0.3 g sodium citrate dissolved in 500 g distilled water to make acidic water) and stir. After dissolution, add distilled water or acidic water to 150 g. After stirring evenly, let it stand for 12 hours and then judge the solubility and stability based on the state of the solution (clear, turbid).

[0124] The experimental results are shown in Table 1 and Figures 2 to 7, where:

[0125] Comparative Example 1 differs from Example 1 in that it does not use cyclodextrin for pre-coating, but instead uses starch or other wall materials for microencapsulation. As shown in Figures 2 and 3, the water-soluble ginger oleoresin microcapsules produced in Example 1 are highly soluble in water and acidic solutions, resulting in clear, transparent solutions with 90% of the particles being below 0.5 μm. In contrast, Comparative Example 1 exhibits average solubility in water and acidic solutions, resulting in a turbid solution, with the turbidity being particularly high in acidic solutions. Furthermore, Comparative Example 1 exhibits lower gingerol content and encapsulation efficiency, and its particle size is relatively large and unevenly distributed. While the spicy sensation in the mouth is low, a stronger spicy sensation in the throat occurs after swallowing.

[0126] The difference between Comparative Example 2 and Example 2 is that myricetin is not added. Comparative Example 2 has good solubility in water and acidic solution, uniform particle size distribution, and 90% of the particle sizes are below 0.5 μm. However, the gingerol content and embedding rate are low, and the spicy sensation in the throat after swallowing is more obvious than that in Example 2.

[0127] The difference between Comparative Example 3 and Example 2 is that the pH of the system was not adjusted when the ginger oleoresin-cyclodextrin dispersion and the wall material solution were emulsified and dispersed, resulting in a very obvious spicy sensation in the oral cavity and throat after swallowing, and the gingerol content and embedding rate were low, and the particle size was large and unevenly distributed.

[0128] The difference between Comparative Example 4 and Example 3 is that the ginger oleoresin homogenate is not subjected to constant temperature static fusion. Although the water solubility and particle size of the microcapsules are not affected, the gingerol content and embedding rate are relatively low, and the spicy sensation in the mouth and throat is more obvious than that in Example 3.

[0129] Comparative Example 5 only uses more cyclodextrin for coating, and does not adopt microencapsulation technology. From the experimental results, it can be seen that the use of cyclodextrin coating alone still has problems such as low gingerol content, low encapsulation rate, strong spicy taste, poor water solubility, and low stability in low pH solution.

[0130] Table 1 Differences between the Examples of the Invention and the Comparative Examples

[0131]

[0132] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing water-soluble ginger oleoresin microcapsules, characterized in that The following steps are included: (1) mixing cyclodextrin with water and heating until completely dissolved to obtain a cyclodextrin solution; then adding ginger oleoresin under high shear conditions to perform emulsification and dispersion to obtain a ginger oleoresin-cyclodextrin dispersion; (2) mixing the wall material and water to prepare a solution and heating the solution to obtain a wall material solution; (3) adding the ginger oleoresin-cyclodextrin dispersion obtained in step (1) to the wall material solution obtained in step (2) under high shear conditions for emulsification and dispersion, and adjusting the pH of the system to 6.5-10.0; then adding flavonoids for continuous emulsification and dispersion to obtain a ginger oleoresin emulsion; and then high-pressure homogenizing the ginger oleoresin emulsion to obtain a ginger oleoresin homogenate; (4) The ginger oleoresin homogenate obtained in step (3) is allowed to stand at a constant temperature, and finally dried to obtain water-soluble ginger oleoresin microcapsules.

2. The method for preparing water-soluble ginger oleoresin microcapsules according to claim 1, characterized in that: The cyclodextrin in step (1) is at least one of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin.

3. The method for preparing water-soluble ginger oleoresin microcapsules according to claim 1, characterized in that: The mass ratio of ginger oleoresin to cyclodextrin in step (1) is (1-2):

1.

4. The method for preparing water-soluble ginger oleoresin microcapsules according to claim 1, characterized in that: The concentration of the cyclodextrin solution in step (1) is 10-50 wt.%.

5. The method for preparing water-soluble ginger oleoresin microcapsules according to claim 1, characterized in that: The wall material in step (2) is at least one of gum arabic, pullulan, modified starch, gum dawa, peach gum, fucoidan and chitosan.

6. The method for preparing water-soluble ginger oleoresin microcapsules according to claim 1, characterized in that: The wall material solution in step (2) also includes a filler; The filler is at least one of maltodextrin, microcrystalline cellulose, glucose syrup, microporous starch, resistant dextrin, white sugar, lactitol, erythritol, maltitol, sorbitol, stachyose, beet water-soluble fiber, trehalose, maltooligosaccharide and lactose.

7. The method for preparing water-soluble ginger oleoresin microcapsules according to claim 1, characterized in that: The mass ratio of the ginger oleoresin-cyclodextrin dispersion to the wall material solution in step (3) is 1:(2.5-3).

8. The method for preparing water-soluble ginger oleoresin microcapsules according to claim 1, characterized in that: The temperature of the constant temperature static state described in step (4) is 30°C to 90°C; The constant temperature standing time described in step (4) is 1h~12h.

9. A water-soluble ginger oleoresin microcapsule, characterized in that The method is obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the water-soluble ginger oleoresin microcapsules according to claim 9 in food, medicine or cosmetics.

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