Dioscorea zingiberensis anthocyanin yeast microcapsule as well as preparation method and application thereof

Abstract

The invention relates to the technical field of functional component microencapsulation, and discloses a dioscorea batatas anthocyanin yeast microcapsule as well as a preparation method and application thereof. The dioscorea batatas is rich in anthocyanin, has remarkable biological activities such as oxidation resistance, inflammation resistance and cardiovascular protection, but is poor in stability and low in bioavailability in a natural state. According to the microcapsule prepared by the invention, the yeast is used as a wall material, and the dioscorea batatas anthocyanin is accurately embedded in the yeast to form microcapsule particles with stable structure and uniform particle size. In the preparation process, key parameters such as the raw material ratio, the reaction temperature and the stirring time are optimized, so that the anthocyanin is efficiently loaded, and the microcapsule has excellent performance. The microcapsule can be used as a natural antioxidant and a coloring agent in the field of food, so that the food quality and safety are improved, and the shelf life is prolonged; in the field of medicine, the compound can be used for developing functional preparations for preventing and treating chronic diseases; in the field of cosmetics, the anti-aging composition can be added into skin care products to exert the anti-oxidation and anti-aging effects, and the market application prospect is extremely wide.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of functional ingredient microencapsulation, and more particularly to a Dioscorea hispida anthocyanin yeast microcapsule, a preparation method and application thereof. BACKGROUND

[0002] Dioscorea hispida is a liana plant of the genus Dioscorea in the family Dioscoreaceae, and the edible part is the underground tuberous stem, which is named "Dioscorea hispida" because of its shape like a toe. Studies have shown that Dioscorea hispida is rich in various trace elements such as phosphorus, calcium, zinc, selenium, etc., in addition to anthocyanins, polysaccharides, amino acids, saponins and other nutrients. As food and medicine, Dioscorea hispida has the effects of invigorating the spleen, nourishing the stomach, tonifying the kidney, lowering blood lipids, regulating blood pressure, treating intestinal inflammation, etc.

[0003] Anthocyanins are a class of natural pigments widely present in plants, belonging to flavonoids, and have various physiological functions such as antioxidant, anti-inflammatory, and protection of vision. In plants, anthocyanins are mostly in the form of glycosides (i.e. anthocyanins). Common anthocyanins in nature include pelargonidin (Pg), cyanidin (Cy), delphinidin (Dp), peonidin (Pn), petunidin (Pt) and malvidin (Mv). Studies have shown that anthocyanins have antibacterial, antitumor, antimutagenic, and anti-radiation properties in medicine. In Dioscorea hispida, anthocyanins mainly exist in the rhizome. Due to its natural, safe and non-toxic properties, it is often used as a natural colorant and functional food additive.

[0004] However, anthocyanins are also extremely sensitive to the environment, and conditions such as light, heat and oxygen can cause them to degrade, limiting their application. Therefore, improving the stability of anthocyanins through microencapsulation technology has become a key research direction. SUMMARY

[0005] The purpose of the present application is to solve the problems of performance limitations and complex preparation of traditional microcapsule materials, and to provide a Dioscorea hispida anthocyanin yeast microcapsule, a preparation method and application thereof. When yeast is used as an encapsulating material, its safety advantage is significant, and it will not cause human rejection reaction, so the safety of anthocyanin products encapsulated by yeast is more guaranteed. At the same time, the porous structure of yeast can accommodate a large number of anthocyanin molecules, and the unique structure of its cell wall and membrane not only helps anthocyanins enter the cell to improve the encapsulation efficiency, but also forms effective protection to improve the stability of anthocyanins; and the cell-free environment provided by yeast also helps to maintain the activity of anthocyanins and prolong the shelf life of the product. In addition, after microencapsulation, the release rate of anthocyanins in intestinal juice and gastric juice is reduced, and it still maintains a certain antioxidant activity, and can effectively reduce the loss under conditions of high temperature, strong light, and lack of oxygen.

[0006] The present application specifically adopts the following technical solutions to achieve the above purpose: The first aspect of the present application provides a microcapsule of Ipomoea batatas anthocyanin and yeast, which is prepared from components including Ipomoea batatas anthocyanin and yeast.

[0007] In the present application, the yeast cell has excellent biocompatibility, porous structure and environmental protection properties. Compared with synthetic materials, the yeast as an encapsulating material will not cause rejection reaction of the human body, and is safer, so the Ipomoea batatas anthocyanin product encapsulated by yeast is safer. The porous structure can accommodate a large number of anthocyanin molecules, the structure of the yeast cell wall and membrane is beneficial to the entry of anthocyanin into the cell to improve the encapsulation efficiency, and can protect the anthocyanin to improve the stability, and the cell-free environment helps to maintain the activity and prolong the shelf life. By adjusting the composition and structure of the yeast wall material, the release rate of formic acid can be controlled. The yeast wall material comes from renewable resources and can be biodegraded after being discarded, which meets the principle of sustainable development.

[0008] Further, the wall-to-core ratio of the Ipomoea batatas anthocyanin and yeast is (1-2):(1-8).

[0009] Further, the yeast is selected from at least one of yellow rice high-activity dry yeast, low-sugar high-activity dry yeast and bread high-activity dry yeast.

[0010] The second aspect of the present application provides a preparation method of the microcapsule of Ipomoea batatas anthocyanin and yeast according to the first aspect, and the method comprises: The inactivated yeast and Ipomoea batatas anthocyanin are mixed in deionized water, and after oscillation and first centrifugation, washing, second centrifugation and freeze-drying, the microcapsule of Ipomoea batatas anthocyanin and yeast is obtained.

[0011] Further, the preparation of the inactivated yeast comprises: placing the dry yeast in an oven with a temperature of 100℃-110℃ for 1-2 hours.

[0012] Further, the oscillation temperature is 28℃-60℃, and the oscillation time is 1h-8h.

[0013] Further, the first centrifugation rate is 4000rpm-5000rpm, and the first centrifugation time is 5min-10min; the second centrifugation rate is 4000rpm-5000rpm, and the second centrifugation time is 5min-10min.

[0014] Further, the freeze-drying temperature is -75℃--65℃, and the time is 36h-48h.

[0015] The beneficial effects of the present application are as follows: The yeast microcapsule of the anthocyanin of the Dioscorea alata and the preparation method thereof have the advantages that the microencapsulation can reduce the release rate of the anthocyanin in the intestinal juice and the gastric juice, has certain antioxidant activity, and can effectively reduce the loss of the anthocyanin under the conditions of high temperature, strong light and oxygen deficiency. Therefore, the yeast cell can be used as a new microcapsule material for embedding the anthocyanin, the utilization rate of the yeast is improved, and the stability of the environment-sensitive compound is enhanced.

[0016] The yeast microcapsule of the anthocyanin of the Dioscorea alata and the preparation method thereof have the advantages that the microencapsulation can reduce the release rate of the anthocyanin in the intestinal juice and the gastric juice, has certain antioxidant activity, and can effectively reduce the loss of the anthocyanin under the conditions of high temperature, strong light and oxygen deficiency. Therefore, the yeast cell can be used as a new microcapsule material for embedding the anthocyanin, the utilization rate of the yeast is improved, and the stability of the environment-sensitive compound is enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The infrared spectrum of the anthocyanin microcapsule of the Dioscorea alata is shown.

[0018] Figure 2 The scanning electron microscope image of the present application is shown.

[0019] Figure 3a The release of the microcapsule in the simulated gastric juice is shown.

[0020] Figure 3b The release of the microcapsule in the simulated intestinal juice is shown.

[0021] Figure 4 The DPPH scavenging capacity of the anthocyanin microcapsule is shown.

[0022] Figure 5 The hydroxyl radical scavenging capacity of the anthocyanin microcapsule is shown.

[0023] Figure 6 The ABTS cation radical scavenging rate of the anthocyanin microcapsule is shown.

[0024] Figure 7 The retention rate of the anthocyanin and the microcapsule under the temperature condition is shown.

[0025] Figure 8 The retention rate of the anthocyanin and the microcapsule under the oxygen condition is shown.

[0026] Figure 9 The retention rate of the anthocyanin and the microcapsule under the light or dark condition is shown. DETAILED DESCRIPTION

[0027] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments of the present application.

[0028] Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] In the embodiments and comparative examples of the present application, foot potato anthocyanins (foot potato freeze-dried and then extracted with 0.1% citric acid); high-activity dry yeast for yellow rice wine (Angel Yeast Co., Ltd.); distilled water.

[0030] Ethanol, sodium carbonate, sodium nitrate, sodium hydroxide, ascorbic acid, hydrogen peroxide, phosphoric acid, ferric chloride (all of which are analytical pure): Xilong Scientific Co., Ltd.; Rutin (analytical pure): Chengdu Man Sit Biological Technology Co., Ltd.; Folin-Ciocalteu phenol (analytical pure): Beijing Solaybao Technology Co., Ltd.; Gallic acid (analytical pure): Shanghai Maikelin Biological Technology Co., Ltd.; 1,1-diphenyl-2-picrylhydrazyl (DPPH) (analytical pure): Tokyo Chemical Industry Co., Ltd.; Ferrous sulfate (analytical pure): Tianjin Zhiyuan Chemical Reagent Co., Ltd.; HCl (analytical pure): Nanchang Xinguang Fine Chemical Factory.

[0031] In the embodiments and comparative examples of the present application, a high-speed pulverizer (model FW80): Tianjin Test Instrument Co., Ltd.; an electronic balance (model ZN-10002): Hangzhou Youheng Weighing Equipment Co., Ltd.; a digital constant-temperature water bath (model HH-4PT): Changzhou Surui Instrument Co., Ltd.; a Fourier infrared spectrometer (Nicolet iS10): Thermo Fisher Co., Ltd. of the United States; a vacuum freeze dryer (Sim Co., Ltd. of the United States); a refrigerated centrifuge (model KH20R): Hunan Kaida Scientific Instrument Co., Ltd.; a UV-visible spectrophotometer (model UV-1800PC): Aoayi Instrument (Shanghai) Co., Ltd.

[0032] Example 1 A foot potato anthocyanin yeast microcapsule and a preparation method thereof Inactivation of dry yeast: The high-activity dry yeast for yellow rice wine was inactivated by high-temperature treatment in a 105℃ oven for 1 hour, and then was cooled, bottled and stored in a desiccator for standby.

[0033] Preparation method of yeast microcapsule: after inactivation, dry yeast and footboard potato anthocyanin were weighed according to the ratio of wall to core 1:2, mixed in deionized water, oscillated at 28℃ for 2h, then centrifuged at 4000r / min for 5min to separate, and the obtained cells were collected. After three water washing and centrifugation at 4000r / min for 5min again, the yeast cells were collected and freeze-dried (temperature-75℃, time 48h), and finally the embedding yeast microcapsule product containing anthocyanin, i.e. anthocyanin microcapsule, was prepared, and the embedding rate was determined.

[0034] Among them, the calculation process of the embedding rate of the anthocyanin microcapsule is as follows: Anthocyanin content: 0.2g of footboard potato anthocyanin was weighed, 20mL of distilled water was added and magnetically stirred for 30min, 0, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0mL was accurately transferred into a 10mL capacity bottle, and the absorbance was measured at 530nm wavelength. The standard curve was drawn with anthocyanin concentration as the abscissa and the corresponding absorbance as the ordinate, and the linear regression equation of anthocyanin content was obtained: y=1.154x-0.0567, r=0.9993.

[0035] Determination of effective ingredient content on the surface of microcapsule: 0.1g of microcapsule prepared in Example 1 was weighed, added with 20mL of distilled water and magnetically stirred for 30min, then filtered, repeated 3 times, and the anthocyanin content was calculated according to the standard curve to determine the effective ingredient content on the surface of microcapsule.

[0036] Determination of effective ingredient content of microcapsule: 0.1g of microcapsule prepared in Example 1 was weighed, added with 20mL of distilled water and ultrasonically oscillated to dissolve, filtered 3 times to combine the filtrate, and the absorbance of the filtrate was measured, and the anthocyanin content was calculated according to the standard curve. The embedding rate calculation formula is:

[0037] Examples 2-6 A footboard potato anthocyanin yeast microcapsule and a preparation method thereof The preparation method is the same as that in Example 1, except that in Examples 2-6, the ratio of inactivated dry yeast to footboard potato anthocyanin is 1:2, 1:1, 4:1, 6:1 and 8:1 respectively.

[0038] Examples 7-11 A footboard potato anthocyanin yeast microcapsule and a preparation method thereof The preparation method is the same as that in Example 6, except that in Examples 7-11, the oscillation temperature is 28℃, 36℃, 44℃, 52℃ and 60℃ respectively.

[0039] Examples 12-16 A footboard potato anthocyanin yeast microcapsule and a preparation method thereof The preparation method is the same as in Example 6, except that in Examples 12-16, the shaking time is 1 hour, 2 hours, 4 hours, 6 hours and 8 hours respectively.

[0040] Example 17 A microcapsule of potato anthocyanin yeast and its preparation method The preparation method is the same as in Example 5, except that in Example 17, the shaking time is 2.5 hours and the shaking temperature is 36°C.

[0041] Table 1. Encapsulation rates of Examples 1-17

[0042] To further verify the advancement of the present invention, the foot-plate potato anthocyanin yeast microcapsules prepared in Example 17 of the present invention were tested as follows.

[0043] Test 1: Fourier transform infrared spectrometer (FTIR): 2 mg of the microcapsule sample prepared in Example 17, yeast cells, and anthocyanin powder were separately and uniformly ground, then mixed with KBr and compressed into tablets. Measurements were performed using a Fourier transform infrared spectrometer. The results are shown in [Figure number missing]. Figure 1 .

[0044] Depend on Figure 1 It can be seen that the core wall is located at 3314.3cm. -1 An NH vibration absorption peak appears at 3301 cm⁻¹, but after encapsulation into microcapsules, this peak shifts to 3301 cm⁻¹. -1 Location; wall material is located at 1658.6cm. -1 The core material contains an absorption peak generated by the bending vibration of the carbonyl peak, while the absorption peak at 1727 cm⁻¹ is located at 1727 cm⁻¹. -1 The peak was present at [location], but after being encapsulated into microcapsules, the peak shifted to 1651.3 cm⁻¹. -1 Location; wall material is located at 1543.7cm. -1 The core material contains an absorption peak generated by the bending vibration of the benzene ring at 1602.4 cm⁻¹. -1 The peak was present at [location], but after being encapsulated in microcapsules, the peak shifted to 1541.3 cm⁻¹. -1 Location; wall material is located at 1076.9cm. -1 1035.4cm -1 The core material contains an absorption peak generated by the bending vibration of the methoxy group, while the absorption peak is located at 1084.3 cm⁻¹. -1 1020.7cm -1 The peak was present at [location], but after being encapsulated in microcapsules, the peak shifted to 1079.4 cm⁻¹. -1 1045.2cm -1The wall material is located at 805.7 cm -1 The core material is located at 859.4 cm -1 The core material is located at 805.7 cm -1 Thus, the absorption peak of the microcapsule after embedding has a certain offset, reduction or increase between the core material and the wall material, indicating that the microcapsule preparation is successful and can be used for independent analysis.

[0045] Test two, electron microscope observation: take a small amount of the prepared footplate anthocyanin microcapsule, yeast cells and footplate anthocyanin powder of example 17, and sprinkle them on the sample table with double-sided tape, and press them moderately. After removing the excess powder, perform gold spraying treatment, and then use a scanning electron microscope (SEM) to select typical areas for observation and photography, and the results are shown in Figure 2 .

[0046] The unembedded yeast wall material ( Figure 2 -A1, Figure 2 -A2), footplate anthocyanin ( Figure 2 -B1, Figure 2 -B2) and footplate anthocyanin microcapsule ( Figure 2 -C1, Figure 2 -C2) were observed by scanning electron microscope.

[0047] As shown in Figure 2 , A1 represents the microscopic morphology of yellow wine yeast at 5000 times magnification, and it can be seen that the yellow wine yeast is basically spherical in shape; B1 represents the microscopic morphology of footplate anthocyanin at 5000 times magnification, which is irregularly crystalline; C1 represents the microscopic morphology of footplate anthocyanin microcapsule at 5000 times magnification, which is slightly spherical, and the surface of the microcapsule presents concave, wrinkled, and not smooth phenomena, and there are unembedded particles on the surface, and some particles are agglomerated together, which is caused by the rapid evaporation of water and the decrease of atmospheric pressure during freeze-drying, and the particles are agglomerated together after drying due to their own certain stickiness. A2, B2 and C2 are observed at 20000 times magnification of the positions of A1, B1 and C1.

[0048] Test three, release of microcapsule 1. Preparation of simulated gastric juice: take 0.2 grams of sodium chloride, 0.7 milliliters of concentrated hydrochloric acid, add 0.32 grams of pepsin, and then dilute with deionized water to a total volume of 100 milliliters. Then, use 1 mole / liter of dilute hydrochloric acid to adjust the pH of the solution to 1.2.

[0049] Equal amounts of the *Polygonum cuspidatum* anthocyanin microcapsules (0.5 g) prepared in Example 17 and the *Polygonum cuspidatum* anthocyanin solution were placed in 50 mL of simulated gastric juice (pH 1.2, containing 3.2 mg / mL pepsin) and stirred at 37 °C. 1.5 mL of the digestive juice was sampled at preset time points (10-180 minutes) to determine the *Polygonum cuspidatum* anthocyanin content, while simultaneously replenishing an equal volume of simulated gastric juice to maintain system equilibrium.

[0050] 2. Preparation of simulated intestinal fluid: Dissolve 1.36 g of potassium dihydrogen phosphate in 100 mL of deionized water, then adjust the pH to 6.8 with 0.1 mol / L sodium hydroxide solution. Separately dissolve 2 g of trypsin in an appropriate amount of deionized water. Mix the two solutions together and continue to dilute with deionized water to a total volume of 200 mL.

[0051] 0.5 g of the *Polygonum cuspidatum* anthocyanin microcapsules prepared in Example 17 and an equal volume of pure *Polygonum cuspidatum* anthocyanin were placed in 50 mL of simulated intestinal fluid and reacted on a constant-temperature shaker at 37°C at a speed of 40 rpm. A certain amount of digestive fluid was taken at 10, 20, 30, 60, 90, 120, 150, and 180 minutes to detect the *Polygonum cuspidatum* anthocyanin content. An equal volume of simulated intestinal fluid was added after each sampling to maintain a constant total volume. The results are as follows: Figures 3a-3b As shown.

[0052] from Figure 3a It can be observed that during simulated gastric digestion, the release rate of anthocyanins is relatively faster, while the release rate of microcapsules tends to be slower. When the digestion time reaches 180 minutes, the release rate of anthocyanins from microcapsules is 16.4%, while the release rate of anthocyanins from unmicroencapsulated sweet potato is as high as 37.7%. Similarly, based on... Figure 3b In a simulated intestinal fluid environment, the release rates of both anthocyanins and microcapsules were relatively slow. After 180 minutes of digestion, the release rates of anthocyanin microcapsules and *Polygonum cuspidatum* anthocyanins were 17.2% and 31.4%, respectively. These data indicate that microencapsulated anthocyanins exhibit stronger stability in a simulated digestive fluid environment compared to unrestricted *Polygonum cuspidatum* anthocyanins. During digestion in the stomach and intestines, the release rate of anthocyanin microcapsules was consistently lower than that of free *Polygonum cuspidatum* anthocyanins. This is mainly attributed to the fact that the wall material of the microcapsules effectively blocks the erosion of anthocyanins by gastric and intestinal juices, thereby slowing down their release rate and protecting the anthocyanins. The study shows that microencapsulation treatment has a certain effect on delaying the release of *Polygonum cuspidatum* anthocyanins under simulated digestion conditions in vitro.

[0053] Test 4: Determination of the antioxidant capacity of microencapsulated anthocyanins DPPH test: The footboard potato anthocyanin microcapsules prepared in Example 17 were dissolved in distilled water to prepare sample solutions of different concentrations, 2 mL of 0.2 mmol / L DPPH solution was added and mixed thoroughly, and then the absorbance was measured at 517 nm after 30 min of reaction in the dark. The absorbance was recorded as A1; the absorbance was measured with anhydrous ethanol instead of the sample solution, and recorded as A0; the absorbance was measured with anhydrous ethanol instead of the DPPH solution, and recorded as A2. When measuring the absorbance, anhydrous ethanol was used as a blank to zero. The DPPH clearance rate r was calculated according to the formula: ) ×100 In the formula: r is the DPPH clearance rate, %; A1 is the absorbance of the microcapsule sample group; A2 is the absorbance of the control group; A0 is the absorbance of the blank group.

[0054] The hydroxyl radical scavenging test was performed as follows: 1.0 mL of the footboard potato anthocyanin microcapsule solution prepared in Example 17, 2 mL of 2 mmol / L ferrous sulfate solution and 2 mL of 6 mmol / L H2O2 solution were sequentially added to a test tube, and then mixed and shaken, and then placed at room temperature for 10 min; then 2 mL of 2 mmol / L salicylic acid solution was added, and then mixed and shaken, and then placed in a 37°C constant temperature water bath for reaction for 30 min. After the reaction was completed, the absorbance of the mixture was measured at a characteristic wavelength of 510 nm with the blank group (distilled water instead of the sample solution) as a reference; the control group used distilled water instead of the salicylic acid solution, and the absorbance was measured by the same method. The sample's ability to scavenge hydroxyl radicals was calculated as follows: × 100 In the formula: Ai is the absorbance of the microcapsule sample group; Aj is the absorbance of the control group; A0 is the absorbance of the blank group.

[0055] ABTS radical scavenging rate determination method: 7 mmol / L ABTS solution and 2.45 mmol / L potassium persulfate solution were mixed in equal amounts, and then reacted in the dark for 16 h to prepare ABTS working solution. 0.2 mL of the microcapsule solution prepared in Example 17 was mixed with 0.8 mL of ABTS working solution at room temperature and reacted for 30 min, and then the absorbance (OD value) was measured at 734 nm. The control group used 0.2 mL of distilled water instead of the sample, the blank group used distilled water and anhydrous ethanol instead of the ABTS radical, and vitamin C was used as a positive control. The average value was obtained by repeating the test three times. The clearance rate was calculated as follows: × 100 In the formula: A'1 is the OD value of the experimental group; A'2 is the OD value of the blank group without ABTS; A'0 is the OD value of the control group without microcapsules. The test results are shown in Figures 4-6 .

[0056] The scavenging effect on DPPH: The scavenging effect of anthocyanin microcapsules on DPPH is shown in Figure 4 As shown in the table, when the concentration of microcapsules is 0.4 mg / mL, the DPPH scavenging rate increases rapidly with the increase of concentration. When the concentration is 0.2-1.0 mg / mL, the concentration of microcapsules is positively correlated with the scavenging rate, and the scavenging rate increases from 16.8% to 78.2%, an increase of 61.4 percentage points. When the concentration is 1.0 mg / mL, the DPPH scavenging rate of microcapsules reaches the maximum value, which is close to the scavenging rate of VC, indicating that anthocyanin microcapsules can effectively scavenge DPPH free radicals.

[0057] The scavenging effect on hydroxyl radicals: The scavenging ability of anthocyanin microcapsules on hydroxyl radicals is shown in Figure 5 As shown in the table, when the concentration of microcapsules is 0.4 mg / mL, the DPPH scavenging rate increases rapidly with the increase of concentration. When the concentration is 0.2-1.0 mg / mL, the concentration of microcapsules is positively correlated with the scavenging rate, and the scavenging rate increases from 16.8% to 78.2%, an increase of 61.4 percentage points. When the concentration is 1.0 mg / mL, the DPPH scavenging rate of microcapsules reaches the maximum value, which is close to the scavenging rate of VC, indicating that anthocyanin microcapsules can effectively scavenge DPPH free radicals.

[0058] The scavenging effect on ABTS cationic radicals: As shown in Figure 6 , within the concentration range of 2-10 mg / mL, the scavenging ability of anthocyanin microcapsules on ABTS cationic radicals is positively correlated with the increase of concentration. When the mass concentration is 10 mg / mL, the scavenging rate reaches the peak value of 43.1%.

[0059] Test five, storage stability analysis of microcapsules Set the temperature at-20℃, 4℃, 28℃, avoid light / natural light, aerobic / anaerobic conditions, and explore the influence on the retention rate of anthocyanin microcapsules of footplate potato prepared in Example 17. Sample every 5 days within 25 days of storage to measure the anthocyanin content, with unembedded anthocyanin as the blank control. Evaluate the storage stability by retention rate, and the results are shown in Figures 7-9 .

[0060]

[0061] As shown in Figure 7 : The retention rate of footplate potato anthocyanin microcapsules and anthocyanin decreases with the extension of storage time, and the higher the temperature, the lower the retention rate. After 25 days of storage at-20℃, the retention rate of footplate potato anthocyanin microcapsules reaches 62.66%, while the retention rate of anthocyanin is 38.89%. At 4℃, the retention rate of footplate potato anthocyanin rapidly decreases to 47.59%, and the retention rate of microcapsules is 61.01%. Under the condition of 28℃, there is little difference between the two, which shows that under the same temperature conditions, the retention rate of microcapsules is higher than that of unembedded anthocyanin, and the microcapsules have better preservation effect in cold place.

[0062] Depend on Figure 8 The results showed that after 25 days of storage under aerobic conditions at room temperature, the retention rates of *Polygonum cuspidatum* anthocyanin microcapsules and anthocyanins were 60.66% and 50.6%, respectively, indicating that anthocyanins had better stability in an aerobic environment. However, after 25 days of storage under aerobic conditions, the retention rates of both decreased significantly and were lower than those under aerobic conditions. This demonstrates that oxygen in the storage environment has a significant impact on the stability of *Polygonum cuspidatum* anthocyanins and their microcapsules, and microencapsulation can reduce the degree of oxidation of *Polygonum cuspidatum* anthocyanins.

[0063] Depend on Figure 9 The results showed that after 25 days of storage at room temperature in the dark, the retention rates of both *Polygonum cuspidatum* anthocyanin microcapsules and anthocyanins decreased, reaching 60.86% and 59.02%, respectively. Under light conditions, the retention rates of *Polygonum cuspidatum* anthocyanin microcapsules and free anthocyanins showed little difference. These results indicate that microencapsulation can improve the storage stability of anthocyanins to some extent, and the retention rate is higher under light-protected conditions, suggesting that light-protected storage is beneficial for maintaining the stability of *Polygonum cuspidatum* anthocyanin microcapsules.

[0064] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the description of the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention.

[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A foot-shaped potato anthocyanin yeast microcapsule, characterized in that, The microcapsules are prepared from components including yam anthocyanins and yeast.

2. The microcapsule according to claim 1, characterized in that, The ratio of the anthocyanins in the foot plate to the yeast core is (1-2):(8-1).

3. The microcapsule according to claim 1, characterized in that, The yeast is selected from at least one of the following: high-activity dry yeast for rice wine, low-sugar high-activity dry yeast, and high-activity dry yeast for bread.

4. The method for preparing the *Potamogeton crispus* anthocyanin yeast microcapsules according to any one of claims 1-3, characterized in that, The method includes: The inactivated yeast and yam anthocyanin were mixed in deionized water, shaken, centrifuged once, washed, centrifuged a second time, and freeze-dried to obtain yam anthocyanin yeast microcapsules.

5. The method according to claim 4, characterized in that, The preparation of the inactivated yeast includes: placing the dry yeast in an oven at a temperature of 100℃~110℃ and keeping it warm for 1 hour to 2 hours.

6. The method according to claim 4, characterized in that, The oscillation temperature is 28℃~60℃, and the oscillation time is 1h~8h.

7. The method according to claim 4, characterized in that, The first centrifugation rate is 4000 rpm to 5000 rpm, and the first centrifugation time is 5 minutes to 10 minutes; the second centrifugation rate is 4000 rpm to 5000 rpm, and the second centrifugation time is 5 minutes to 10 minutes.

8. The method according to claim 4, characterized in that, The freeze-drying temperature is -75℃ to -65℃, and the time is 36h to 48h.

9. A microcapsule form of anthocyanin can be made into health foods, functional foods, and cosmetics such as face creams, to exert corresponding health care, nutritional enhancement and skin care effects, including the *Potamogeton crispus* anthocyanin yeast microcapsules as described in any one of claims 1-3 or the *Potamogeton crispus* anthocyanin yeast microcapsules as described in any one of claims 4-8.

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