Water-soluble gingerol resin microcapsule, and preparation method and application thereof

Abstract

This invention relates to the field of microencapsulation technology for natural products, specifically to a water-soluble ginger oleoresin microcapsule, its preparation method, and its applications. The invention uses modified starch, plant polysaccharides, etc., as wall materials and ginger oleoresin as the core material. The ginger oleoresin microcapsule product is obtained through processes such as ginger oleoresin molecule coating, emulsification, high-pressure homogenization, constant-temperature standing, and drying. This product features high gingerol content, good water solubility, and low spiciness in the solution. It also exhibits good stability in acidic solutions, meeting the requirements of high stability, no precipitation, low spiciness, and good heat sensitivity in low pH environments. It is suitable for use in food, beverages, health foods, pharmaceuticals, cosmetics, and other fields.

Description

Technical Field

[0001] This invention relates to the field of microencapsulation technology of natural products, specifically to a water-soluble ginger oleoresin microcapsule, its preparation method, and its application. Background Technology

[0002] Ginger, a perennial herb belonging to the genus Zingiber of the family Zingiberaceae, is also known as Jun ginger or white ginger. my country is the origin of ginger and one of its major producing countries. Ginger is widely distributed in my country and has a cultivation history of over 2000 years. It is rich in nutrients, mainly including gingerol, starch, dietary fiber, protein, fat, and trace elements. In daily life, ginger is often used as a seasoning to enhance aroma and flavor. It is also widely used as a traditional Chinese medicine ingredient for the treatment and prevention of various diseases. The *Compendium of Materia Medica* records that ginger is "hot in nature and pungent in taste, entering the heart, kidney, spleen, stomach, and lung meridians," possessing the effects of warming the middle jiao and dispelling cold, restoring yang and unblocking the meridians, and dispelling dampness and reducing inflammation. The *Shennong's Classic of Materia Medica* lists it as a superior herb, stating that it can be used as a vegetable, a condiment, a fruit, and a medicine, its benefits are extensive. Currently, ginger is widely used in food, medicine, health food, and cosmetics.

[0003] Gingerol is the collective name for the "spicy" components of ginger. It is a yellow to yellowish-brown oily substance, insoluble in water but soluble in lipophilic solvents such as ethanol, benzene, and ether. It is a mixture of various substances. The main components include gingerols, zingiberols, gingerols, gingerones, gingerols, gingerenes, gingerdiols, gingerols, and neogingols, containing flavonoids with 3-methoxy-4-hydroxyphenyl compounds. As the main active substance in ginger, gingerol has significant antioxidant and anti-inflammatory effects, and possesses good stomach-strengthening, liver-protecting, choleretic, antiemetic, anti-gastric ulcer, anticoagulant, and tumor-inhibiting 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 by extraction and concentration from ginger. It has a strong ginger flavor and its main components are fat-soluble substances such as ginger essential oil and gingerol. It is widely used in condiments, health foods and pharmaceuticals with antioxidant and anti-inflammatory properties.

[0005] With economic development, consumers are paying more attention to health and have increased demands for diversified and functional foods, leading to a growing need for healthy raw materials from natural sources. The preparation of gingerol resin microcapsules—characterized by high gingerol content, low spiciness, good water solubility, and stable application in low pH environments (such as beverages, oral liquids, candies, solid beverages, and frozen drinks)—using food-grade or naturally sourced, highly safe raw materials has become a pressing market need with significant demand.

[0006] Research on the preparation of ginger oleoresin microcapsules using ginger has been reported in relevant literature and patents, such as "The Influence of Spray Drying Conditions on Ginger Oleoresin Microcapsules" (Food Science, Vol. 3, 2009, School of Food Science and Engineering, Yangzhou University). This report describes the preparation of ginger oleoresin microcapsules using ginger as raw material, through ethanol extraction and vacuum drying, and using β-cyclodextrin and Tween-80 as wall materials, followed by emulsification, homogenization, and spray drying. The main focus was on the influence of different spray drying conditions on ginger oleoresin microcapsules. Chinese patent CN 101473954A discloses a ginger oleoresin microcapsule and its preparation method; Chinese patent CN 113424958A discloses a high gingerol content masking microcapsule and its preparation method; Chinese patent CN113952314A discloses a tea polyphenol-gingerol combined microparticle and its preparation method and application; Chinese patent CN109511983A discloses a ginger oleoresin microcapsule and its preparation method; Chinese patent CN 102895189A discloses a gingerol liposome and its preparation method, etc. While the aforementioned processes can improve the solubility of gingerol to some extent, most of them are quite complex and involve the use of large amounts of chemically synthesized surfactants such as Tween, monoglycerides, sucrose esters, and polyethylene glycol. This raises concerns about food safety, and the products often suffer from low gingerol content, strong spiciness, poor water solubility, and low stability in low pH solutions. These issues fail to meet the health and safety requirements of food products, as well as the quality requirements of beverages, oral liquids, candies, solid beverages, and frozen drinks for gingerol microcapsule powder with high gingerol content, low spiciness, good water solubility, and stable application in low pH environments. Summary of the Invention

[0007] To overcome the shortcomings and disadvantages of the existing technology, the primary objective of this invention is to provide a method for preparing water-soluble ginger oleoresin microcapsules. This method does not use chemical surfactants or chemical solvents, but uses widely available food raw materials and employs a combination of techniques such as molecular encapsulation, emulsification, homogenization, and microcapsule drying to obtain a ginger oleoresin microcapsule product with high gingerol content, low spiciness, good heat sensation, good water solubility, and stability in low pH solution environments.

[0008] Another objective of this invention is to provide water-soluble ginger oleoresin microcapsules prepared by the above-mentioned preparation method. These ginger oleoresin microcapsules have the characteristics of high gingerol content, low spiciness in aqueous solution, good water solubility, high solution clarity, and good stability in low pH solution environment, which can meet the special requirements of food such as beverages, oral liquids, candies, solid beverages and frozen drinks, as well as pharmaceuticals.

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

[0010] The objective of this invention is achieved through the following technical solution:

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

[0012] (1) Mix cyclic dextrin with water and heat until completely dissolved to obtain a cyclic dextrin solution; then add ginger oleoresin under high shear conditions for emulsification and dispersion to obtain ginger oleoresin-cyclic dextrin dispersion.

[0013] (2) Mix the wall material and water to prepare a solution and heat it to obtain a wall material solution;

[0014] (3) Under high shear conditions, the ginger oleoresin-cyclodextrin dispersion obtained in step (1) is added to the wall material solution obtained in step (2) for emulsification and dispersion, and the pH of the system is adjusted to 6.5-10.0; then flavonoids are added for continuous emulsification and dispersion to obtain ginger oleoresin emulsion; then the ginger oleoresin emulsion is homogenized under high pressure to obtain ginger oleoresin homogenate.

[0015] (4) The homogenized ginger oil resin solution obtained in step (3) was kept at a constant temperature and then dried to obtain water-soluble ginger oil resin microcapsules.

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

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

[0018] The heating temperature mentioned in step (1) is 40℃~90℃;

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

[0020] The temperature of the ginger oleoresin mentioned in step (1) is 20℃~80℃, preferably 40℃~70℃;

[0021] The rotation speed of the emulsification dispersion in step (1) is 500 rpm to 20000 rpm, preferably 3000 rpm to 10000 rpm; the emulsification dispersion time is 0.5 min to 60 min, preferably 10 min to 30 min; and the emulsion dispersion temperature is 40℃ to 90℃.

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

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

[0024] The wall material solution described in step (2) preferably also 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, maltodextrin, and lactose.

[0026] The wall material solution contains a wall material concentration of 5 wt.% to 70 wt.% and a filler concentration of 5 wt.% to 70 wt.%.

[0027] The temperature of the wall material solution in steps (2) and (3) is 40℃~90℃, preferably 40℃~80℃;

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

[0029] The rotation speed of the emulsification dispersion in step (3) is 500 rpm to 20000 rpm, preferably 3000 rpm to 10000 rpm; the emulsification dispersion time is 0.5 min to 60 min, preferably 10 min to 30 min; and the emulsification dispersion temperature is 40℃ to 90℃, preferably 40℃ to 80℃.

[0030] The reagent used to adjust 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 preferred pH of the system described in step (3) is 7.0–9.0;

[0032] The flavonoids mentioned in step (3) are at least one of EGCG, hesperidin, dihydromyricetin, myricetin, rutin and quercetin, and the amount added is 0.01 wt.% to 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 high-pressure homogenization process in step (3) is performed 1 to 3 times, preferably 1 to 2 times;

[0035] The temperature for constant temperature standing in step (4) is 30℃~90℃, preferably 40℃~80℃;

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

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

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

[0039] The preferred inlet air temperature for the centrifugal spray dryer is 160℃~200℃, and the preferred outlet air temperature is 70℃~100℃.

[0040] A water-soluble ginger oleoresin microcapsule was prepared by the above method;

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

[0042] The present invention does not impose any special restrictions on the form of the food, which can be added to liquid or solid foods, and is preferably prepared as a beverage.

[0043] If the food is a health food, the present invention does not impose any special restrictions on the dosage form of the health food, which can be capsules, tablets, oral liquids, etc.

[0044] The principle of this invention:

[0045] Cyclic dextrin molecules possess a slightly conical, hollow cylindrical three-dimensional cyclic structure. Within this hollow structure, the upper outer end (larger opening) is composed of C2 and C3 secondary hydroxyl groups, while the lower end (smaller opening) is composed of C6 primary hydroxyl groups, exhibiting hydrophilicity. However, the cavity itself, shielded by CH bonds, forms a hydrophobic region, exhibiting a degree of nonpolarity. The hollow structure within the cyclic dextrin molecule can accommodate other molecules of similar molecular weight. This invention employs a cyclic dextrin molecule pre-coating technology. Taking advantage of the ease with which gingerol components in ginger oleoresin can be embedded within the hollow structure of cyclic dextrin molecules, ginger oleoresin is pre-coated. Generally, molecules embedded within the cyclic dextrin hollow structure are released very slowly, thus achieving a certain degree of reduction in spiciness.

[0046] Due to the poor water solubility of cyclodextrins, relying solely on the incorporation of active ingredients from gingerol and other ginger oleoresins with cyclodextrin results in a limited amount of pre-coating, leading to a low gingerol content in the final product. To increase gingerol content, the proportion of gingerol must be increased. However, this results in a significant amount of gingerol remaining uncoated in the gingerol-cyclodextrin dispersion during the pre-coating process, leading to a noticeable spiciness that fails to meet actual requirements. To address these technical issues, this invention, based on the pre-coating of cyclodextrin molecules, further incorporates microencapsulation technology. Modified starch is used for microencapsulation emulsification and secondary encapsulation, thereby increasing gingerol content, effectively reducing spiciness, and improving water solubility and stability.

[0047] Furthermore, gingerol in ginger oleoresin is easily converted to shogaol (which has a much spicier taste than gingerol) under heating and low pH conditions. Therefore, during microencapsulation and secondary encapsulation, this invention effectively prevents the conversion of gingerol to shogaol by rationally controlling the pH of the solution, further increasing the gingerol content while avoiding increased spiciness. The addition of flavonoids further improves the product's stability.

[0048] The present invention has the following advantages and effects compared with 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, resulting in products with high application safety and low cost. No chemical solvents are used in the preparation process, making the production process safer and conducive to the industrial production scale-up of the product.

[0050] (2) This invention uses a combination of cyclic dextrin molecule pre-coating and microcapsule encapsulation technology. By controlling the pH value of the liquid system and using flavonoids as an aid, the encapsulation amount is increased, the stability of gingerol components is maintained, and the spiciness is reduced, thereby achieving the technical effects of high gingerol content, high water solubility, low spiciness, and good heat sensation.

[0051] (3) After the homogenization of ginger oil resin emulsion is completed, the present invention adopts a constant temperature static fusion method to further enhance the effective coating of ginger oil resin by the colloid, improve the encapsulation rate of the product, and ensure the stability during application.

[0052] (4) The water-soluble ginger oil resin 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 solubility of the water-soluble ginger oil resin microcapsules is significantly improved, and it has good water solubility. Its aqueous solution is clear and transparent and has low spiciness; in addition, the water-soluble ginger oil resin microcapsules have the characteristics of good stability in low pH solution environment, and it does not become turbid or precipitate in acidic solution, has high stability, and its pH tolerance is significantly improved.

[0053] (5) The water-soluble ginger oil resin microcapsules prepared by the present invention can meet the special requirements of food (beverages, oral liquids, candies, solid beverages, cold drinks, etc.), pharmaceuticals and cosmetics, and have broad application prospects. Attached Figure Description

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

[0055] Figure 2 The images show the dissolution effect of the water-soluble ginger oleoresin microcapsules prepared in Examples 1-3 in a neutral aqueous solution, where Examples 1-3 are shown from left to right.

[0056] Figure 3 The diagram shows the dissolution effect of water-soluble ginger oleoresin microcapsules prepared in comparative examples 1 to 5 in neutral aqueous solution. From left to right, they represent comparative examples 1 to 5.

[0057] Figure 4 These are images showing the dissolution effect of the water-soluble ginger oleoresin microcapsules prepared in Examples 1-3 in acidic aqueous solution, where Examples 1-3 are shown from left to right.

[0058] Figure 5 The diagram shows the dissolution effect of water-soluble ginger oleoresin microcapsules prepared in acidic aqueous solution in Comparative Examples 1 to 5, from left to right.

[0059] Figure 6 This is a particle size distribution diagram of the water-soluble ginger oil resin microcapsules prepared in Examples 1-3.

[0060] Figure 7 This is a particle size distribution diagram of the water-soluble ginger oil resin microcapsules prepared in proportions 1 to 5. Detailed Implementation

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

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

[0063] In this embodiment, the ginger oleoresin was commercially available, and its gingerol content was 41.6%. Its solubility in neutral aqueous solution is shown in [reference needed]. Figure 1 .

[0064] Example 1

[0065] (1) Ginger oleoresin with a gingerol content of 41.6% was placed in an environment of 50℃ and kept at a constant temperature; 28g of α-cyclodextrin and 10g of β-cyclodextrin were weighed and added to 52g of deionized water, and heated in a water bath to 75℃ to keep the solution completely dissolved; then 63g of the above ginger oleoresin was added under high shear conditions and fully emulsified and dispersed (emulsification and dispersion speed was 3000rpm, time was 16min, emulsion temperature was 72℃~78℃) to obtain ginger oleoresin-cyclodextrin dispersion;

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

[0067] (3) Maintain the temperature of the wall material solution in step (2), and add the ginger oleoresin-cyclodextrin dispersion obtained in step (1) to the wall material solution under high shear conditions for thorough emulsification and dispersion (emulsification and dispersion speed is 4500 rpm, time is 20 min, emulsion temperature is 69℃~75℃); at the same time, add sodium carbonate and sodium hexametaphosphate to adjust the pH value of the system to 7.9; then add EGCG (addition amount is 0.1% of the final product), and continue emulsification and dispersion until it is completely dissolved to form a uniform ginger oleoresin emulsion; then homogenize the ginger oleoresin emulsion under high pressure (homogenization pressure 75 MPa, homogenization 2 times) to obtain a stable ginger oleoresin homogenate.

[0068] (4) The homogenized ginger oil resin solution obtained in step (3) was kept at a constant temperature of 45°C for 5 hours and then spray-dried. The inlet air temperature was 170°C to 195°C and the outlet air temperature was 80°C to 95°C to obtain water-soluble ginger oil resin microcapsules.

[0069] Testing revealed that the water-soluble ginger oleoresin microcapsules exhibited excellent water solubility, producing a clear and transparent solution. The gingerol content was 10.9 wt.%, with an encapsulation rate of 97.6%. The capsules also showed low levels of spiciness in the oral cavity and throat.

[0070] Example 2

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

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

[0073] (3) Maintain the temperature of the wall material solution in step (2), and add the ginger oleoresin-cyclodextrin dispersion obtained in step (1) to the wall material solution under high shear conditions, and fully emulsify and disperse it (emulsification and dispersion speed is 5000 rpm, time is 15 min, emulsion temperature is 72℃~77℃); at the same time, add potassium carbonate and sodium pyrophosphate to adjust the pH value of the system to 8.2; then add myricetin (addition amount is 0.08% of the final product), and continue to emulsify and disperse until it is completely dissolved to form a uniform ginger oleoresin emulsion; then homogenize the ginger oleoresin emulsion under high pressure (homogenization pressure 80 MPa, homogenization 2 times) to obtain a stable ginger oleoresin homogenized solution.

[0074] (4) The homogenized ginger oil resin solution obtained in step (3) was kept at a constant temperature of 45°C for 5 hours and then spray-dried. The inlet air temperature was 170°C to 195°C and the outlet air temperature was 80°C to 95°C to obtain water-soluble ginger oil resin microcapsules.

[0075] Testing revealed that the water-soluble ginger oleoresin microcapsules exhibited excellent water solubility, producing a clear and transparent solution. The gingerol content was 10.5 wt.%, with an encapsulation rate of 97.3%. The capsules also showed low levels of spiciness in the oral cavity and throat.

[0076] Example 3

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

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

[0079] (3) Maintain the temperature of the wall material solution in step (2), and add the ginger oleoresin-cyclodextrin dispersion obtained in step (1) to the wall material solution under high shear conditions, and fully emulsify and disperse it (emulsification and dispersion speed is 6000 rpm, time is 18 min, emulsion temperature is 75℃~80℃); at the same time, add sodium carbonate and sodium tripolyphosphate to adjust the pH value of the system to 8.3; then add quercetin (addition amount is 0.12% of the final product), and continue to emulsify and disperse until it is completely dissolved to form a uniform ginger oleoresin emulsion; then homogenize the ginger oleoresin emulsion under high pressure (homogenization pressure 50 MPa, homogenization 2 times) to obtain a stable ginger oleoresin homogenate.

[0080] (4) The homogenized ginger oil resin solution obtained in step (3) was kept at a constant temperature of 50°C for 5 hours and then spray-dried. The inlet air temperature was 170°C to 195°C and the outlet air temperature was 80°C to 95°C to obtain water-soluble ginger oil resin microcapsules.

[0081] Testing revealed that the water-soluble ginger oleoresin microcapsules exhibited excellent water solubility, producing a clear and transparent solution. The gingerol content was 11.7 wt.%, with an encapsulation rate of 98.3%. The capsules also showed low levels of spiciness in the oral cavity and throat.

[0082] Comparative Example 1 (microencapsulation was performed directly using starch and other wall materials without pre-coating with cyclodextrin)

[0083] (1) Place ginger oil resin with a gingerol content of 41.6% in a 55℃ environment for heat preservation and static storage;

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

[0085] (3) Maintain the temperature of the wall material solution in step (2), and add 63g of ginger oil resin from step (1) to the wall material solution under high shear conditions, and fully emulsify and disperse it (emulsification and dispersion speed is 4500 rpm, time is 20 min, emulsion temperature is 69℃~75℃). At the same time, add sodium carbonate and sodium hexametaphosphate to adjust the pH of the system to 7.9; then add EGCG (addition amount is 0.1% of the final product), and continue to emulsify and disperse until it is completely dissolved to form ginger oil resin emulsion; then homogenize the ginger oil resin emulsion under high pressure (homogenization pressure 75 MPa, homogenization 2 times) to obtain ginger oil resin homogenized liquid;

[0086] (4) The homogenized ginger oil resin solution obtained in step (3) was kept at a constant temperature of 45°C for 5 hours and then spray-dried. The inlet air temperature was 170°C to 195°C and the outlet air temperature was 80°C to 95°C to obtain water-soluble ginger oil resin microcapsules.

[0087] Tests showed that the water-soluble ginger oleoresin microcapsules had moderate water solubility, the solution was relatively turbid, the gingerol content was 9.1 wt.%, the encapsulation rate was 75.7%, the oral spiciness was low, and the pharyngeal spiciness was high.

[0088] Comparative Example 2 (without added myricetin)

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

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

[0091] (3) Keep the temperature of the wall material solution in step (2) and add the ginger oleoresin-cyclodextrin dispersion obtained in step (1) to the wall material solution under high shear conditions to fully emulsify and disperse (emulsification and dispersion speed is 5000 rpm, time is 15 min, emulsion temperature is 72℃~77℃); at the same time, add potassium carbonate and sodium pyrophosphate to adjust the pH value of the system to 8.2 to obtain ginger oleoresin emulsion; then homogenize the ginger oleoresin emulsion under high pressure (homogenization pressure 80 MPa, homogenization 2 times) to obtain ginger oleoresin homogenized liquid.

[0092] (4) The homogenized ginger oil resin solution obtained in step (3) was kept at a constant temperature of 45°C for 5 hours and then spray-dried. The inlet air temperature was 170°C to 195°C and the outlet air temperature was 80°C to 95°C to obtain water-soluble ginger oil resin microcapsules.

[0093] Testing revealed that the water-soluble ginger oleoresin microcapsules exhibited excellent water solubility, producing a clear and transparent solution. The gingerol content was 8.7 wt.%, with an encapsulation rate of 81.6%. The oral spiciness was low, while the pharyngeal spiciness was moderate.

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

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

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

[0097] (3) Keep the temperature of the wall material solution in step (2) and add the ginger oleoresin-cyclodextrin dispersion obtained in step (1) to the wall material solution under high shear conditions, and fully emulsify and disperse it (emulsification and dispersion speed is 5000 rpm, time is 15 min, emulsion temperature is 72℃~77℃); then add myricetin (addition amount is 0.08% of the final product), and continue to emulsify and disperse until it is completely dissolved to form ginger oleoresin emulsion; then homogenize the ginger oleoresin emulsion under high pressure (homogenization pressure 80 MPa, homogenization 2 times) to obtain ginger oleoresin homogenized liquid.

[0098] (4) The homogenized ginger oil resin solution obtained in step (3) was kept at a constant temperature of 45°C for 5 hours and then spray-dried. The inlet air temperature was 170°C to 195°C and the outlet air temperature was 80°C to 95°C to obtain water-soluble ginger oil resin microcapsules.

[0099] Testing revealed that the water-soluble ginger oleoresin microcapsules had moderate water solubility, the solution was turbid, the gingerol content was 8.8 wt.%, the encapsulation rate was 79.2%, and the oral and pharyngeal spiciness was high.

[0100] Comparative Example 4 (drying was performed directly without constant temperature fusion).

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

[0104] (4) The homogenized ginger oil resin solution obtained in step (3) is directly spray-dried, wherein the drying air inlet temperature is 170℃~195℃ and the air outlet temperature is 80℃~95℃, to obtain water-soluble ginger oil resin microcapsules.

[0105] Testing revealed that the water-soluble ginger oleoresin microcapsules exhibited excellent water solubility, producing a clear and transparent solution. The gingerol content was 9.8 wt.%, with an encapsulation rate of 88.3%. The oral and pharyngeal spiciness was moderate.

[0106] Comparative Example 5 (encapsulation was performed using cyclodextrin alone, without microencapsulation technology).

[0107] (1) Ginger oleoresin with a gingerol content of 41.6% was placed in a 50°C environment for incubation and static treatment; 38g of α-cyclodextrin and 26g of β-cyclodextrin were weighed and added to 366g of deionized water, and heated in a water bath to 75°C to keep the solution completely dissolved; then 63g of the above ginger oleoresin was added under high shear conditions and fully emulsified and dispersed (emulsification and dispersion speed was 3000rpm, time was 16min, emulsion temperature was 72°C~78°C) to obtain ginger oleoresin-cyclodextrin dispersion;

[0108] (2) The ginger oleoresin-cyclodextrin dispersion was then subjected to high-pressure homogenization (homogenization pressure 75 MPa, homogenization 2 times) to obtain ginger oleoresin homogenized solution.

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

[0110] Testing revealed that the water-soluble ginger oleoresin microcapsules had moderate water solubility, the solution was turbid, the gingerol content was 6.1 wt.%, the encapsulation rate was 33.6%, and the spiciness was high in the oral cavity and throat.

[0111] Effect Example

[0112] (1) Determination of embedding rate

[0113] ① Determination of gingerol content in microcapsules: Accurately weigh 5g of water-soluble ginger oil resin microcapsule sample, add 15mL of water to form a homogeneous system, centrifuge at 4000r / min for 30min, discard the supernatant, and tilt the centrifuge container for a period of time to remove surface moisture from the residue at the bottom of the centrifuge container. Then, pour in 35mL of anhydrous ethanol to dissolve the ginger oil. Determine the gingerol content using spectrophotometry at 280nm.

[0114] ② Determination of gingerol content on the surface of microcapsules: Accurately weigh 5g of water-soluble ginger oleoresin microcapsule sample, add 25mL of anhydrous ethanol, stir on a stirrer for 5min, filter the mixture with filter paper, and wash the microcapsules on the filter paper with anhydrous ethanol to remove the gingerol on the surface. Make up the volume to 50mL. Determine the gingerol content by spectrophotometry at 280nm.

[0115] ③ Encapsulation rate calculation: Encapsulation rate (%) = (1 - gingerol content on the surface of microcapsules) * 100 / gingerol content in microcapsules.

[0116] (2) Spiciness determination

[0117] The water-soluble ginger oleoresin microcapsule samples prepared in Examples 1-3 and Comparative Examples 1-5 were numbered 1-8 sequentially. Ginger oleoresin solutions of the same concentration (0.2 wt.%) were prepared using purified water. Eighteen individuals were randomly selected to taste each of the eight solutions sequentially, evaluating the spiciness in the mouth and throat using a choice of high, medium, and low. The overall spiciness level was determined by combining the evaluations of the 18 individuals. (Apply boiled water to the mouth between each solution tasting to avoid being affected by the previous solution.)

[0118] (3) Content of gingerol in microcapsules

[0119] Weigh an appropriate amount of water-soluble ginger oleoresin microcapsule sample and sonicate it in 15 mL of water for 10 min to completely dissolve it. Transfer the solution to a 50 mL volumetric flask and dilute to the mark with methanol to obtain the sample solution. The preparation of the standard substance solution and the specific determination method refer to the national standard GB / T 22293-2008 Determination of the main irritating components of ginger and its oleoresin by HPLC.

[0120] (4) Determination of microcapsule particle size

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

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

[0123] Accurately weigh 0.1500g of water-soluble ginger oleoresin microcapsule sample, add a small amount of distilled water or acidic water (0.5g citric acid and 0.3 sodium citrate dissolved in 500g distilled water to prepare acidic water), stir, and after dissolving, add distilled water or acidic water to 150g, stir evenly, and let stand for 12h. Then judge the solubility and stability according to the state of the solution (clear or turbid).

[0124] The experimental results are shown in Table 1. Figures 2-7 ,in:

[0125] The difference between Comparative Example 1 and Example 1 is that cyclodextrin is not used for pre-coating; instead, starch and other wall materials are used for direct microencapsulation. Figure 2 and Figure 3 It can be seen that the water-soluble ginger oleoresin microcapsules prepared in Example 1 have high solubility in water and acidic solutions, and the solutions are clear and transparent, with 90% of the particles having a diameter of less than 0.5 μm. In contrast, the solubility of Comparative Example 1 in water and acidic solutions is generally poor, and the solutions are more turbid, especially in acidic solutions where the turbidity is even higher. Furthermore, Comparative Example 1 has lower gingerol content and encapsulation efficiency, and the particle size is larger and unevenly distributed. Although the initial spiciness is low, the spiciness in the throat is greater after swallowing.

[0126] The difference between Comparative Example 2 and Example 2 is that myricetin was not added. Myricetin has good solubility in water and acidic solutions, uniform particle size distribution, and 90% of the particles are below 0.5 μm. However, the content and encapsulation rate of gingerol are lower, and the spiciness 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 during the emulsification and dispersion of the ginger oleoresin-cyclodextrin dispersion and the wall material solution, which resulted in a very obvious spiciness in the oral cavity and pharynx after swallowing, and the gingerol content and encapsulation rate were low, with larger particle size and uneven distribution.

[0128] The difference between Comparative Example 4 and Example 3 is that the ginger oil resin homogenate was not subjected to constant temperature static fusion. Although the water solubility and particle size of the microcapsules were not affected, the gingerol content and encapsulation rate were lower, and the oral and pharyngeal spiciness was more pronounced than in Example 3.

[0129] Comparative Example 5 used only a large amount of cyclodextrin for coating without microencapsulation technology. The experimental results show that using cyclodextrin alone still has problems such as low gingerol content, low encapsulation rate, strong spiciness, poor water solubility, and low stability in low pH solutions.

[0130] Table 1. Differences between the embodiments of the present invention and the comparative examples.

[0131]

[0132]

[0133] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing water-soluble ginger oleoresin microcapsules, characterized in that... It includes the following steps: (1) Mix cyclic dextrin with water and heat until completely dissolved to obtain a cyclic dextrin solution; then add ginger oleoresin under high shear conditions for emulsification and dispersion to obtain ginger oleoresin-cyclic dextrin dispersion. (2) Mix the wall material and water to prepare a solution and heat it to obtain a wall material solution; (3) Under high shear conditions, the ginger oleoresin-cyclodextrin dispersion obtained in step (1) is added to the wall material solution obtained in step (2) for emulsification and dispersion, and the pH of the system is adjusted to 6.5~10.0; then flavonoids are added for continuous emulsification and dispersion to obtain ginger oleoresin emulsion; then the ginger oleoresin emulsion is homogenized under high pressure to obtain ginger oleoresin homogenate. (4) The homogenized ginger oil resin solution obtained in step (3) was kept at a constant temperature and then dried to obtain water-soluble ginger oil resin microcapsules. The speed of emulsification and dispersion in step (1) is 3000 rpm to 10000 rpm; the time of emulsification and dispersion is 10 min to 30 min; and the temperature of emulsion dispersion is 40℃ to 90℃. The constant temperature for static setting mentioned in step (4) is 40℃~80℃; The constant temperature standing time mentioned in step (4) is 1h~12h.

2. The method for preparing water-soluble ginger oleoresin microcapsules according to claim 1, characterized in that: The cyclodextrin mentioned 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 between ginger oleoresin and 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 mentioned 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 mentioned in step (2) is at least one of gum arabic, pullulan, modified starch, dawa gum, 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 described 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, maltodextrin, and lactose.

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

8. A water-soluble ginger oleoresin microcapsule, characterized in that... It is obtained by the preparation method according to any one of claims 1 to 7.

9. The use of the water-soluble ginger oleoresin microcapsules according to claim 8 in food, pharmaceuticals or cosmetics.

Images