Method for stabilizing anthocyanins in high-acid juice in the presence of vc

Abstract

The application belongs to the technical field of beverage processing, and discloses a method for stabilizing anthocyanin in high-acid fruit juice in the presence of Vc. A stabilizer is added to fruit juice containing Vc and anthocyanin at a final concentration of 0.1-1.0 g / L, then inert gas is introduced into the fruit juice and ultrasonic degassing is performed, and the dissolved oxygen content in the fruit juice is controlled to be lower than 1 mg / L. The stabilizer is a mixture of sinapinic acid, caffeic acid and tea polyphenol, and the mass ratio of sinapinic acid, caffeic acid and tea polyphenol is 5-25:5-25:0.03-3. In one aspect, the application uses traditional sinapinic acid and caffeic acid as raw materials to inhibit the mutual promotion degradation between Vc and anthocyanin. In another aspect, the application innovatively uses tea polyphenol as a stabilizer.

Description

Technical Field

[0001] This application relates to the field of beverage processing technology, and in particular to a method for stabilizing anthocyanins in high-acid fruit juice under the coexistence of vitamin C. Background Technology

[0002] Anthocyanins are a class of natural, water-soluble pigments widely found in fruits and vegetables, giving fruit and vegetable juices their vibrant colors. Vitamin C is a naturally occurring nutrient in high-acid fruit juices and is also a commonly used food antioxidant, often used in juice processing to delay oxidative spoilage. Existing research indicates that when vitamin C and anthocyanins coexist, they undergo synergistic degradation, leading to further deterioration of juice quality. This adds to the difficulty of developing high-acid compound fruit and vegetable juices.

[0003] High-acid fruits (specifically between pH 2.5 and 3.1) usually contain high concentrations of vitamin C. Under these pH conditions, anthocyanins exhibit a polymorphic structure, including flavonoid cations, quinone bases, hemiacetals, cis- and trans-chalcones. Flavonoid cations are the dominant structure, making it difficult for them to bind with proteins and polysaccharides. Consequently, proteins and polysaccharides that have a color-protecting effect on anthocyanins under relatively high pH conditions cannot effectively bind with anthocyanins and thus cannot exert their color-protecting effect.

[0004] Therefore, in order to address the technical challenge of accelerated anthocyanin degradation in high-acid fruit juice systems where vitamin C and anthocyanins coexist, developing a method that can efficiently stabilize anthocyanins in high-acid fruit juices is of significant practical importance and application value.

[0005] Chinese patent application 202411411070.6 discloses a method and application for controlling color deterioration during the storage of black rice wine. The method states: "The method includes the following steps: adding a co-pigment solution to black rice wine, stirring, and then storing it in the dark at 1-3°C for 0.5-4 hours, followed by storage at room temperature in the dark for 5-90 days. The molar ratio of anthocyanins to co-pigments in the black rice wine is 1:5-100, and the co-pigments are selected from at least one of the following: sinapic acid (SIA), ferulic acid (FA), and caffeic acid (CA). SIA, FA, and CA react with the anthocyanins in the black rice wine during storage to form a new pigment—pyran anthocyanin. Pyran ring anthocyanins are protected from nucleophilic attack and possess better resistance to high temperatures, acids and alkalis, light, and oxygen, thereby improving the color stability of the black rice wine during the later stages of storage."

[0006] It is evident that this scheme provides the application of substances such as sinapic acid, ferulic acid, and caffeic acid, as well as the mechanism by which they enhance the stability of anthocyanins;

[0007] However, upon closer examination of the plan, it did not disclose the application of tea polyphenols;

[0008] Furthermore, Chinese patent application 202410816589.6 discloses an edible coating liquid and its preparation method and application, which is formulated with chitosan, blackberry anthocyanins and tea polyphenols as raw materials;

[0009] The solution states that "using chitosan as the coating liquid matrix and adding blackberry anthocyanins and tea polyphenols as active substances can effectively improve the preservation effect of the coating liquid without changing the transparency of the coating liquid and thus affecting the sensory quality of the preserved meat."

[0010] It is evident that the scheme indicates that the functions of anthocyanins and tea polyphenols are both preservation, and it fails to recognize that tea polyphenols have the ability to stabilize anthocyanins.

[0011] The problem this solution aims to solve is: how to provide a method that can efficiently stabilize anthocyanins in high-acid fruit juices. Summary of the Invention

[0012] The purpose of this application is to provide a method for efficiently stabilizing anthocyanins in high-acid fruit juice. On the one hand, this method uses traditional sinapic acid and caffeic acid as raw materials to inhibit the mutual promotion of degradation between vitamin C and anthocyanins. On the other hand, this application innovatively uses tea polyphenols as a stabilizer to further synergize with caffeic acid and sinapic acid to inhibit the degradation of anthocyanins.

[0013] To achieve the above objectives, this application discloses a method for stabilizing anthocyanins in high-acid fruit juice under the coexistence of vitamin C and vitamin C. The stabilizer is added to the fruit juice containing vitamin C and anthocyanins at a final concentration of 0.1 to 1.0 g / L, and then an inert gas is introduced into the fruit juice and ultrasonically degassed to control the dissolved oxygen content in the fruit juice to be below 1 mg / L.

[0014] The stabilizer is a mixture of sinapic acid, caffeic acid and tea polyphenols, and the mass ratio of sinapic acid, caffeic acid and tea polyphenols is 5-25:5-25:0.03-3.

[0015] In addition, it should be noted that in this application, sinapic acid and caffeic acid may inhibit the degradation of anthocyanins by reducing intermediate products of vitamin C degradation and by reacting with anthocyanins to generate pyranoanthocyanins; tea polyphenols may inhibit vitamin C degradation through antioxidant activity and by forming complexes with anthocyanins through electrostatic interactions to inhibit anthocyanin degradation.

[0016] Preferably, the stabilizer further includes L-cysteine, and the mass ratio of sinapic acid, caffeic acid, tea polyphenols and L-cysteine ​​is 5-25:5-25:0.03-3:0.07-7.

[0017] Furthermore, in this application, the mechanism by which L-cysteine ​​inhibits the degradation of anthocyanins may be by enhancing the dispersibility of anthocyanins and vitamin C, increasing the intermolecular distance, and thus weakening the interaction between the two.

[0018] Preferably, the pH value of the juice containing vitamin C and anthocyanins is 2.5 to 3.1.

[0019] Preferably, the high-acid fruit juice is at least one of blueberry juice, mulberry juice, bayberry juice, lemon juice, lime juice, and prickly pear juice.

[0020] Preferably, the high-acid fruit juice is a compound fruit juice formed by mixing at least one of blueberry juice, mulberry juice, and bayberry juice with at least one of lemon juice, lime juice, and prickly pear juice.

[0021] Preferably, the high-acid fruit juice is a compound fruit juice formed by blending bayberry juice, mulberry juice and lemon juice;

[0022] Furthermore, the mass ratio of bayberry juice, mulberry juice, and lemon juice is 8–12:8–12:1.

[0023] Preferably, during the process of introducing inert gas into the juice, the inert gas is introduced from the bottom of the juice at a flow rate of 1 to 3 times the volume of the juice per minute.

[0024] The ultrasonic degassing time is 3 to 5 minutes.

[0025] The beneficial effects of this application are:

[0026] This application provides a method for efficiently stabilizing anthocyanins in high-acid fruit juice. In this application, traditional sinapic acid and caffeic acid are used as raw materials to inhibit the problem of mutual degradation between vitamin C and anthocyanins. On the other hand, this application innovatively uses tea polyphenols as a stabilizer.

[0027] Among them, sinapic acid and caffeic acid may inhibit the degradation of anthocyanins by reducing intermediate products of vitamin C degradation and by reacting with anthocyanins to form pyran anthocyanins; tea polyphenols may inhibit vitamin C degradation through antioxidant activity and form complexes with anthocyanins through electrostatic interactions to reduce the degradation of anthocyanins. Furthermore, this application has also found through experiments that tea polyphenols have a certain synergistic effect with caffeic acid and sinapic acid in stabilizing anthocyanins. Detailed Implementation

[0028] The present application will be clearly and completely described below with reference to its embodiments. It should be noted that, unless specific conditions are specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0029] Example 1

[0030] Weigh out frozen bayberry juice (tested to have a pH of approximately 3.1) to obtain a high-acid juice.

[0031] Add food-grade sinapic acid, caffeic acid, and tea polyphenols (stabilizer) to the high-acid fruit juice, stir well, and make the total final concentration of sinapic acid, caffeic acid, and tea polyphenols in the fruit juice 0.8 g / L, and the mass ratio of sinapic acid, caffeic acid, and tea polyphenols 5:5:3.

[0032] Then, nitrogen gas is introduced into the juice from the bottom at a flow rate of twice the juice volume per minute, and ultrasonic degassing is performed for 4 minutes to control the dissolved oxygen content in the juice system to be below 1 mg / L; subsequently, it is boiled for sterilization, filled, and cooled to room temperature.

[0033] Example 2

[0034] Weigh out frozen bayberry juice (tested to have a pH of approximately 3.1 ± 0.2) to obtain a high-acid juice.

[0035] Add food-grade sinapic acid, caffeic acid, and tea polyphenols (stabilizer) to the high-acid fruit juice, stir well, and make the total final concentration of sinapic acid, caffeic acid, and tea polyphenols in the fruit juice 0.7 g / L, and the mass ratio of sinapic acid, caffeic acid, and tea polyphenols 25:25:0.03.

[0036] Then, nitrogen gas is introduced into the juice from the bottom at a flow rate of 3 times the juice volume per minute, and ultrasonic degassing is performed for a total of 3 minutes to control the dissolved oxygen content in the juice system to be below 1 mg / L; subsequently, it is boiled for sterilization, then filled and cooled to room temperature.

[0037] Example 3

[0038] Weigh out frozen bayberry juice (tested to have a pH of approximately 3.1) to obtain a high-acid juice.

[0039] Add food-grade sinapic acid, caffeic acid, and tea polyphenols (stabilizer) to the high-acid fruit juice, stir well, and make the total final concentration of sinapic acid, caffeic acid, and tea polyphenols in the fruit juice 0.9 g / L, and the mass ratio of sinapic acid, caffeic acid, and tea polyphenols 10:10:1.

[0040] Then, nitrogen gas is introduced into the juice from the bottom at a flow rate of 1 times the juice volume per minute, and ultrasonic degassing is performed for a total of 5 minutes to control the dissolved oxygen content in the juice system to be below 1 mg / L; subsequently, it is boiled for sterilization, filled, and cooled to room temperature.

[0041] Example 4

[0042] The method is basically the same as in Example 1, except that a mixture of mulberry juice and lemon juice is used instead of bayberry juice, and the mass ratio of mulberry juice to lemon juice is 8:1. The pH value of the mixture is approximately (3.1±0.2).

[0043] Example 5

[0044] The method is basically the same as in Example 1, except that a mixture of bayberry juice, mulberry juice and lemon juice with a pH of approximately (3.1±0.2) is used to replace the bayberry juice, and the mass ratio of bayberry juice, mulberry juice and lemon juice is 9:8:1.

[0045] Example 6

[0046] The method is basically the same as in Example 1, except that the stabilizers in Example 1 are replaced with sinapic acid, caffeic acid, tea polyphenols and L-cysteine. The final concentration of the stabilizer in the juice is 0.8 g / L, and the mass ratio of sinapic acid, caffeic acid, tea polyphenols and L-cysteine ​​is 5:5:3:3.

[0047] Example 7

[0048] The method is basically the same as in Example 6, except that a mixture of bayberry juice, mulberry juice and lemon juice with a pH of approximately (3.1±0.2) is used instead of bayberry juice, and the mass ratio of bayberry juice, mulberry juice and lemon juice is 9:8:1.

[0049] Comparative Example 1

[0050] The results are basically the same as in Example 1, except that a stabilizer composed of sinapic acid and caffeic acid is used instead of the stabilizer composed of sinapic acid, caffeic acid and tea polyphenols in Example 1, and the mass ratio of sinapic acid to caffeic acid is 5:5.

[0051] Comparative Example 2

[0052] It is basically the same as Example 1, except that tea polyphenols are used as a stabilizer to replace the stabilizer composed of sinapic acid, caffeic acid and tea polyphenols in Example 1.

[0053] Anthocyanin degradation test

[0054] To accelerate anthocyanin degradation and facilitate comparison between the examples and comparative examples, vitamin C was added to both the examples and comparative examples to achieve a final concentration of 200 mg / L. The juices were then stored at 37°C for 12 days. The absorbance values ​​of the juices from the examples and comparative examples were measured. It should be noted that during absorbance testing, the error is relatively small and the results are more accurate when the absorbance value is between 0.15 and 0.8. Furthermore, since different juices have varying color depths, this application used different dilution ratios to ensure the initial absorbance values ​​of different samples were within the range of 0.45-0.55 during actual testing to minimize errors.

[0055] More specifically, when the juice is bayberry juice, the actual dilution ratio is 8 times, that is, the actual dilution ratio of Examples 1-3, Example 6, and Comparative Examples 1-2 is 8 times;

[0056] When the juice is a mixture of mulberry juice and lemon juice, the actual dilution ratio is 25 times, that is, the actual dilution ratio of Example 4 is 25 times;

[0057] When the juice is a mixture of bayberry juice, mulberry juice and lemon juice, the actual dilution ratio is 15 times, that is, the actual dilution ratio of Examples 5 and 7 is 15 times;

[0058] Subsequently, the solution was filtered through a 0.22 μm filter membrane, and the absorbance of the filtrate at 510 nm was measured.

[0059] Table 2: Detection results of absorbance value of fruit juice at 510 nm

[0060] sample Initial absorbance absorbance after 12 days of storage 12-day absorbance attenuation rate (%) Example 1 0.474 0.425 10.34% Example 2 0.478 0.419 12.34% Example 3 0.469 0.430 8.32% Example 4 0.532 0.447 15.98% Example 5 0.495 0.432 12.73% Example 6 0.477 0.429 10.06% Example 7 0.491 0.463 5.70% Comparative Example 1 0.475 0.353 25.68% Comparative Example 2 0.479 0.297 38.00%

[0061] Results Analysis

[0062] 1. As can be seen from the observation of Examples 1-3, when the amount of stabilizer added and the proportion of each raw material in the stabilizer were slightly adjusted in the preparation process of bayberry juice, the ability to resist the decay of light absorption value in Examples 1-3 fluctuated, proving that its ability to stabilize anthocyanins changed, but it still remained at a relatively high level overall.

[0063] Further observation of Comparative Examples 1-2 shows that when the stabilizer contains only a mixture of sinapic acid and caffeic acid or only tea polyphenols, the ability of both to resist the attenuation of absorbance value decreases significantly, and the absorbance value drops sharply. It can be seen that when sinapic acid, caffeic acid and tea polyphenols are used together, the stabilizer has a more advantageous effect on stabilizing anthocyanins.

[0064] 2. As can be seen from Examples 1 and 6, the actual dilution factor for both is 8 times. Based on this, when Example 6 uses a stabilizer containing L-cysteine, its 12-day absorbance attenuation rate is comparable to that of Example 1.

[0065] Further examples 5 and 7 show that the actual dilution factor for both is 15 times, and theoretically the concentration of the stabilizer is less than that in examples 1 and 6 (of course, the concentration of anthocyanins is also less than that in examples 1 and 6, and the mass ratio between anthocyanins and stabilizers has not actually changed).

[0066] However, observing the 12-day absorbance attenuation rates of Examples 5 and 7, it can be seen that they are 12.73% and 5.70%, respectively; it can be seen that when L-cysteine ​​is added to the stabilizer, its ability to stabilize a single fruit juice system is the same as that of the stabilizer composed of sinapic acid, caffeic acid and tea polyphenols.

[0067] However, when the system is a mixed fruit juice system consisting of multiple fruit juices, adding L-cysteine ​​as a stabilizer is more advantageous.

Claims

1. A method for stabilizing anthocyanins in high-acid fruit juice under conditions of coexistence of vitamin C, characterized in that, The stabilizer was added to the juice containing vitamin C and anthocyanins at a final concentration of 0.1–1.0 g / L. Then, inert gas was introduced into the juice and ultrasonic degassing was performed to control the dissolved oxygen content in the juice to be below 1 mg / L. The stabilizer is a mixture of sinapic acid, caffeic acid and tea polyphenols, and the mass ratio of sinapic acid, caffeic acid and tea polyphenols is 5-25:5-25:0.03-3.

2. The method for stabilizing anthocyanins in high-acid fruit juice under the coexistence of vitamin C and vitamin C according to claim 1, characterized in that, The stabilizer also includes L-cysteine, and the mass ratio of sinapic acid, caffeic acid, tea polyphenols and L-cysteine ​​is 5-25:5-25:0.03-3:0.07-7.

3. The method for stabilizing anthocyanins in high-acid fruit juice under the coexistence of vitamin C and vitamin C according to claim 1, characterized in that, The pH value of the juice containing vitamin C and anthocyanins is 2.5 to 3.

1.

4. The method for stabilizing anthocyanins in high-acid fruit juice under the coexistence of vitamin C and vitamin C according to claim 1, characterized in that, High-acid fruit juices include at least one of the following: blueberry juice, mulberry juice, bayberry juice, lemon juice, lime juice, and prickly pear juice.

5. The method for stabilizing anthocyanins in high-acid fruit juice under the coexistence of vitamin C and vitamin C according to claim 4, characterized in that, The high-acid fruit juice is a compound fruit juice formed by mixing at least one of blueberry juice, mulberry juice, and bayberry juice with at least one of lemon juice, lime juice, and prickly pear juice.

6. The method for stabilizing anthocyanins in high-acid fruit juice under the coexistence of vitamin C and vitamin C according to claim 4, characterized in that, The high-acid fruit juice is a compound fruit juice formed by blending bayberry juice, mulberry juice and lemon juice; Furthermore, the mass ratio of bayberry juice, mulberry juice, and lemon juice is 8–12:8–12:

1.

7. The method for stabilizing anthocyanins in high-acid fruit juice under the coexistence of vitamin C and vitamin C according to claim 6, characterized in that, During the process of introducing inert gas into the juice, the inert gas is introduced from the bottom of the juice at a flow rate of 1 to 3 times the volume of the juice per minute. The ultrasonic degassing time is 3 to 5 minutes.