Preparation method and application of anthocyanin and anthocyanin high-thermal-stability compound

Abstract

The preparation method comprises the following steps: (1) preparation of mung bean porous starch: adding water into mung bean starch, uniformly mixing, heating and gelatinizing, pouring starch paste into an ethanol solution while the starch paste is hot, uniformly mixing, sealing to prevent ethanol from escaping, then carrying out ultrasonic treatment, standing, and filtering out ethanol; and soaking the obtained starch in ethanol flowing by using a circulating device, fishing out the starch, drying to completely remove the ethanol, and then crushing and sieving to obtain the mung bean porous starch. And (2) preparation of the mung bean porous starch-anthocyanin compound: adding the mung bean porous starch into an anthocyanin solution, mixing and compounding, filtering, and drying left solid particles to obtain the mung bean porous starch-anthocyanin compound. The material has high thermal stability and load capacity, and has wide application scenarios.

Description

Technical Field

[0001] The present invention relates to the preparation of heat - stable complexes, and particularly to a method for preparing a high - heat - stability complex of anthocyanin and its application. Background Art

[0002] Anthocyanins are a class of natural water - soluble pigments widely present in plants, with physiological activities such as antioxidant, anti - inflammatory, and anti - cancer effects. However, the phenolic hydroxyl groups in the anthocyanin molecular structure are easily affected by light, heat, pH value, and oxygen, resulting in fading and degradation. Currently, common carriers for loading anthocyanins include microcapsules, nanoparticles, and modified starches, etc. Among them, starch - based carriers have attracted much attention due to their good biocompatibility and low cost. However, the loading rate and protection effect of traditional starch on anthocyanins are limited. For example, ordinary starch has a small specific surface area, and the anthocyanins are prone to leakage or decomposition at high temperatures after loading, making it difficult to meet the requirements of food processing. CN110447817A discloses a method for improving the stability of anthocyanins. Starch and anthocyanins are blended in hydrochloric acid aqueous solution, and after treatment under a certain pressure, the starch is gelatinized and interacts with anthocyanins. Then, it is stored at a certain temperature to further strengthen the interaction between anthocyanins and starch, forming a complex. The present invention has the effect of improving the stability of anthocyanins, can improve food quality, and extend the shelf life of food. However, it requires ultra - high - pressure operation, and the equipment cost is relatively high; moreover, although the heat - stable effect has increased to some extent, it still does not meet the expectations. CN113575951B discloses a starch - based dual - loaded functional nanoparticle, its preparation method and application. Polypeptides are obtained by subjecting egg high - density lipoproteins to restricted hydrolysis treatment with protease; a mixed system containing the polypeptides and quercetin is self - assembled under alkaline conditions to form micelle nanoparticles; a mixed system containing the micelle nanoparticles and anthocyanins is subjected to a covalent grafting reaction in an alkaline environment to form a graft; carboxymethyl dextrin is complexed with the graft to obtain a starch - based dual - loaded functional nanoparticle. The steps are very complex and not suitable for industrialization. CN109820747A discloses a granule containing anthocyanins and its preparation process. The granule includes a core and a coating layer covering the surface of the core. By mass percentage: the core includes 3 - 97% anthocyanins and 3 - 97% niacinamide, the filler layer includes 5 - 50% microcrystalline cellulose and 50 - 95% mannitol, the coating layer includes 1 - 99% modified corn starch and 1 - 99% chitosan, or the coating layer includes 100% modified corn starch, or the coating layer includes 100% chitosan. It is necessary to form a wrapped form.

[0003] In addition, the high - heat - stability complex of anthocyanin and the good gel performance can be used as food ink materials to customize products.

[0004] Therefore, it is urgent to develop a composite with a high loading rate and thermal stability. Summary of the Invention

[0005] The object of the present invention is to provide a method for preparing a composite of anthocyanin with high thermal stability in view of the deficiencies of the prior art, including: (1) Preparation of mung bean porous starch: Add water to mung bean starch, mix evenly, then gelatinize. Subsequently, pour the starch paste into an ethanol solution while it is still hot, mix evenly, seal to prevent ethanol from escaping, then perform ultrasonic treatment, and then filter off the ethanol after standing. Then soak the starch in ethanol flowing through a circulation device, take out the starch, and dry it to completely remove ethanol, and then crush and sieve it to obtain mung bean porous starch.

[0006] (2) Preparation of mung bean porous starch-anthocyanin composite: Add mung bean porous starch to an anthocyanin solution, mix and compound, then filter, and dry the remaining solid particles to obtain the mung bean porous starch-anthocyanin composite.

[0007] Furthermore, the ratio of mung bean starch to water is 1:3 - 1:30, preferably 1:10.

[0008] Furthermore, the gelatinization conditions are heating at a temperature of 70 - 95°C for about 5 - 60 min, for example, heating at a temperature of 90°C for about 15 min.

[0009] Furthermore, the volume ratio of water to ethanol is 1:(0.5 - 10), for example, 1:2.

[0010] Furthermore, ultrasonic treatment is carried out for 0.5 - 60 min, for example, 1 - 30 min, 15 min.

[0011] Furthermore, the ultrasonic power is 100 - 800 W, for example, 240 W.

[0012] Furthermore, soak in ethanol flowing through a circulation device for 0.2 - 6 h, for example, 2 h.

[0013] Furthermore, the anthocyanin solution is 0.2 - 10 mg / ml, for example, 1 - 5 mg / ml, for example, 1.5 mg / ml anthocyanin solution.

[0014] Furthermore, the mass-volume ratio of mung bean porous starch to anthocyanin solution is 1:(5 - 200) (g / ml), for example, 1:40 (g / ml) mass-volume ratio.

[0015] Furthermore, the drying method is selected from one of oven drying, hot air drying, natural air drying, and freeze drying.

[0016] The present invention also provides a method for preparing an anthocyanin high thermal stability complex, which uses anthocyanin to replace the above-mentioned cyanidin.

[0017] The present invention also provides an anthocyanin cyanidin high thermal stability complex, which is prepared by the above method.

[0018] The present invention also provides an application of the anthocyanin cyanidin high thermal stability complex, using the prepared anthocyanin cyanidin high thermal stability complex as a food additive and / or a food ink material and / or a packaging indicating label.

[0019] Specifically, for an application of the anthocyanin cyanidin high thermal stability complex, the prepared anthocyanin cyanidin high thermal stability complex is used as a food additive and added to baked foods to increase the nutritional value of the baked foods, endow them with a natural purple color, and extend their shelf life.

[0020] Specifically, for an application of the anthocyanin cyanidin high thermal stability complex, the prepared anthocyanin cyanidin high thermal stability complex is used as a food ink material for 3D printing foods: due to the high thermal stability and gel performance of the complex, it can be used as a food ink material to customize products.

[0021] Specifically, for an application of the anthocyanin cyanidin high thermal stability complex, the prepared anthocyanin cyanidin high thermal stability complex is used as a packaging indicating label, an intelligent packaging indicating label: by utilizing the stability of the complex and the property that cyanidin changes with pH, it can be used to detect the freshness of the food inside the package. Description of the Drawings

[0022] Figure 1 It is a physical picture of the original mung bean starch and the mung bean porous starch-cyanidin complex; Figure 2 It is the laser confocal imaging situation of the porous starch-cyanidin complex prepared without ultrasonic treatment (left figure) and the porous starch-cyanidin complex prepared with ultrasonic treatment. Detailed Embodiments

[0023] For the convenience of understanding by those skilled in the art, the present invention will be further described below in conjunction with embodiments. The content mentioned in the embodiments does not limit the present invention. Embodiment

[0024] Preparation process of mung bean porous starch Weigh 10 g of mung bean starch, add 100 ml of water, mix evenly, and then heat and gelatinize at 90 °C for about 15 min. Subsequently, pour the starch paste into 200 ml of ethanol solution while it is still hot, stir while pouring to mix evenly, then quickly seal to prevent ethanol from escaping, and place it in an ultrasonic cleaner with a power of 240 W at 25 °C for 15 min. Then, after standing for 45 min, filter off the ethanol. Then soak the starch in 200 ml of ethanol flowing through a circulation device for 2 h, take out the starch, place it in an oven at 50 °C for about 8 h to completely remove the ethanol, and then crush it and pass it through a 150-mesh sieve to obtain mung bean porous starch.

[0025] Preparation process of mung bean porous starch-anthocyanin complex Add mung bean porous starch to a 1.5 mg / ml anthocyanin solution at a mass-to-volume ratio of 1:40 (g / ml), shake at 150 rpm for 150 min, then filter. Dry the remaining solid particles in an oven at 50 °C for about 3 min to obtain mung bean porous starch-anthocyanin complex.

[0026] Comparative example 1 Soak it directly in 200 ml of ethanol flowing through a circulation device for 2 h after gelatinization, that is, omit "pour the starch paste into 200 ml of ethanol solution while it is still hot, stir while pouring to mix evenly, then quickly seal to prevent ethanol from escaping, and place it in an ultrasonic cleaner with a power of 240 W at 25 °C for 15 min. Then, after standing for 45 min, filter off the ethanol." Others are the same as in Example 1.

[0027] Comparative example 2 Omit "soak the starch in 200 ml of ethanol flowing through a circulation device for 2 h and then take out the starch", that is, filter off the ethanol after ultrasonic treatment and standing, and dry directly. Others are the same as in Example 1.

[0028] Comparative example 3 Use corn starch to replace mung bean starch, and others are the same as in Example 1.

[0029] Experimental results of adsorption capacity: The adsorption capacity of the original mung bean starch for anthocyanin is 1.9326 ± 0.1964 mg / g, and the adsorption capacity of the mung bean porous starch modified by the method of this application for anthocyanin is 4.9070 ± 0.1761 mg / ml. The adsorption capacity of Comparative example 1 for anthocyanin is 2.673 ± 0.1282 mg / g, the adsorption capacity of Comparative example 2 for anthocyanin is 2.673 ± 0.1282 mg / g, and the adsorption capacity of Comparative example 3 for anthocyanin is 3.214 ± 0.1815 mg / g.

[0030] The adsorption capacity of mung bean porous starch modified by the method of the present application for anthocyanins has increased by about 153% compared to the original mung bean starch. Mixing with ethanol and ultrasonic treatment, as well as soaking in flowing ethanol using a circulation device, can all improve the adsorption effect of anthocyanins; however, the combined use has a better effect. Mung bean starch shows a more excellent adsorption effect than corn starch, probably because the content of amylopectin in mung beans is higher, and more pores are easily formed during the preparation of porous starch, so the adsorption capacity for anthocyanins is stronger and the adsorption amount is higher.

[0031] Results of the thermal stability experiment: The thermal stability of the mung bean porous starch-anthocyanin complex has been significantly improved compared to anthocyanins not loaded with mung bean porous starch. When heated in a water bath at 100 °C for 2 h, the retention rate of anthocyanins in the mung bean porous starch-anthocyanin complex of the present application is 79.41%, and the retention rate of unloaded anthocyanins is 57.82%. The retention rate of anthocyanins in Comparative Example 1 is 67.86%, that in Comparative Example 2 is 63.17%, and the retention rate in Comparative Example 3 is 76.41%. It can be seen that the combined use has a better effect and a higher retention rate of anthocyanins, indicating that the adsorption is deeper and more firm. The retention rate of anthocyanins in Comparative Example 3 is basically equivalent to that of the present application.

[0032] When the mung bean porous starch-anthocyanin complex is heated in a water bath at 50 °C and 80 °C for 2 h respectively, the retention rates of anthocyanins in the mung bean porous starch-anthocyanin complex are 94.21% and 82.98% respectively, showing better retention effects.

[0033] Table 1 Chromaticity analysis of the porous starch-anthocyanin complex prepared without ultrasonic treatment and the anthocyanin complex prepared with ultrasonic treatment

[0034] From Figure 2 and Table 1, it can be seen that after ultrasonic treatment, the laser intensity of the complex increases significantly; there is a difference in chromaticity between the complex without ultrasonic treatment (Comparative Example 1) and the complex with ultrasonic treatment at the 0.01 level. Therefore, from the perspective of the laser intensity of the complex, it also proves that the complex prepared in the present application has good adsorption performance.

[0035] Those skilled in the art of the present technology can understand that unless otherwise defined, all terms (including technical terms and scientific terms) used here have the same meaning as the general understanding of those of ordinary skill in the art to which the present invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless specifically defined as here.

[0036] It should be understood that the detailed description of the technical solutions of the present invention by means of the preferred embodiments above is illustrative rather than restrictive. Those of ordinary skill in the art can modify the technical solutions described in each embodiment on the basis of reading the specification of the present invention, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims

1. A method for preparing a high thermal stability complex of anthocyanin and anthocyanidin, characterized in that: It includes: (1) Preparation of mung bean porous starch: Add water to mung bean starch, mix evenly, then gelatinize. Subsequently, pour the starch paste into an ethanol solution while it is still hot, mix evenly, seal to prevent ethanol from escaping, then perform ultrasonic treatment. After standing, filter off the ethanol. Then soak the starch in ethanol flowing through a circulation device, take out the starch, dry it to completely remove ethanol, then pulverize it and sieve it to obtain mung bean porous starch; (2) Preparation of mung bean porous starch - anthocyanin complex: Add mung bean porous starch to an anthocyanin solution, mix and compound, then filter. Dry the remaining solid particles to obtain the mung bean porous starch - anthocyanin complex.

2. The method according to claim 1, characterized in that: The mass ratio of mung bean starch to water is 1:3 - 1:30, preferably 1:

10.

3. The method according to claim 1, wherein: The gelatinization conditions are heating at a temperature of 70 - 95°C for about 5 - 60 minutes, for example, heating at a temperature of 90°C for about 15 minutes.

4. The method according to claim 1, characterized in that: The volume ratio of water to ethanol is 1:(0.5 - 10), for example, 1:2; And / or, ultrasonic treatment for 0.5 - 60 minutes, for example, 1 - 30 minutes, 15 minutes; And / or, the ultrasonic power is 100 - 800 W, for example, 240 W.

5. The method according to claim 1, characterized in that: The anthocyanin solution is an anthocyanin solution with a concentration of 0.2 - 10 mg / ml, for example, 1 - 5 mg / ml, for example, 1.5 mg / ml.

6. The method according to claim 1, wherein: The mass - volume ratio of mung bean porous starch to the anthocyanin solution is 1:(5 - 200) (g / ml), for example, the mass - volume ratio of 1:40 (g / ml).

7. A method for preparing a high thermal stability complex of anthocyanin, using anthocyanin to replace the above - mentioned anthocyanidin.

8. A high thermal stability complex of anthocyanin or anthocyanidin, prepared by the method according to any one of claims 1 - 7.

9. An application of the high thermal stability complex of anthocyanin and anthocyanidin, using the prepared high thermal stability complex of anthocyanin and anthocyanidin as a food additive and / or a food ink material and / or a packaging indication label.

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