A kind of curcumin low sodium salt and preparation method thereof

Abstract

This invention belongs to the technical field of high-value applications of curcumin, specifically relating to a low-sodium curcumin salt and its preparation method. Using γ-cyclodextrin as a backbone, the invention loads curcumin and sodium chloride via a cosolvent precipitation method to produce a γ-cyclodextrin-curcumin-sodium chloride complex, i.e., a curcumin-flavored low-sodium salt. This provides new insights into the development of low-sodium flavored health foods and has important guiding significance for the prevention and control of chronic diseases caused by a high-sodium diet.

Description

Technical field:

[0001] The invention belongs to the technical field of high-value application of curcumin, and particularly relates to a low-sodium salt of curcumin and a preparation method thereof. Background technology:

[0002] Currently, the preparation of low-sodium salt mainly achieves the goal of reducing salt by adjusting the composition of table salt and the spatial structure or spatial distribution of sodium chloride, and is developing in the direction of health, deliciousness, and low cost. The low-sodium salt products developed by China Salt Group achieve the health goal of reducing salt without reducing saltiness by replacing the sodium in traditional table salt with a certain proportion of potassium. However, while potassium chloride increases saltiness, it also increases bitterness. To this end, other flavor substances such as citric acid, salty peptides, and magnesium chloride are often introduced on the basis of sodium chloride and potassium chloride. In addition, hollow salt microspheres can enhance the perception of saltiness by increasing the specific surface area of ​​sodium chloride distribution. Sodium chloride salt particles prepared by radio frequency heating with citric acid cross-linked chitosan also have a stronger salty perception.

[0003] The promotion and application of low-sodium salt in the modern food industry must address the issue of food preservation and freshness. Sodium chloride is a traditional food preservative that inactivates harmful microorganisms primarily through the high osmotic pressure caused by high sodium chloride concentrations. Therefore, the inhibition or inactivation of the growth of harmful microorganisms in low-sodium scenarios has become an issue that needs urgent consideration. Curcumin, as a natural polyphenol, has multiple physiological activities such as anti-inflammatory, antioxidant, regulating intestinal flora, and preventing chronic diseases. It is also a food-grade sound and light sensitizer that can inactivate foodborne harmful microorganisms. Currently, there is no product that combines curcumin with salt, which has both flavoring properties and antibacterial properties. Summary of the invention:

[0004] The technical problem to be solved by the present invention is that the problem of food preservation and freshness must be solved during the promotion and application of low-sodium salt in the modern food industry. At present, there is no product that combines curcumin with salt to have both seasoning properties and antibacterial properties.

[0005] To solve the above problems, the present invention prepares curcumin flavored low sodium salt by solvent co-precipitation freeze-drying, determines the preparation conditions of curcumin flavored low sodium salt, explores the binding mechanism of curcumin, γ-cyclodextrin and sodium chloride to form a complex, and clarifies the function and flavor characteristics of curcumin flavored low sodium salt. The obtained curcumin flavored low sodium salt has good antioxidant capacity and stability, pleasant fat and vanilla flavors, stronger salty taste perception and lower bitter taste perception than sodium chloride. In addition, it can also mediate the acousto-photodynamic inactivation of Shewanella putrefaciens and Vibrio parahaemolyticus. The present invention provides a new idea for the development of low-sodium flavored healthy foods and has important guiding significance for the prevention and control of chronic diseases caused by a high-sodium diet.

[0006] To achieve the above object, the present invention is implemented by the following technical scheme: a method for preparing curcumin flavored low sodium salt, comprising the following steps:

[0007] (1) dissolving curcumin in anhydrous ethanol to obtain a curcumin stock solution;

[0008] (2) Dissolving γ-cyclodextrin and sodium chloride in pure water, and then dissolving the curcumin stock solution in step (1) in a proportion in a mixed aqueous solution of γ-cyclodextrin and sodium chloride, stirring continuously for a period of time, centrifuging and discarding the precipitate, and freeze-drying the supernatant to obtain curcumin low sodium salt. With stirring and mixing, the aromatic groups at both ends of the curcumin are wrapped into the interior of the γ-cyclodextrin cavity, and the sodium chloride is attached to the surface of the γ-cyclodextrin.

[0009] Furthermore, the concentration of the curcumin stock solution in step (1) is 10-37 mg / mL.

[0010] Furthermore, in step (2), the volume ratio of the mixed solution of γ-cyclodextrin and sodium chloride to the curcumin stock solution is 25:4.

[0011] Furthermore, the concentration of γ-cyclodextrin in step (2) is 4 to 28×10 6 mol / mL, and the concentration of sodium chloride is 2% to 10% (w / v).

[0012] Furthermore, in step (2), curcumin:γ-cyclodextrin:sodium chloride are mixed in a mass ratio of 37:130:500.

[0013] Furthermore, in step (2), the stirring time is 6 to 48 hours, the stirring speed is 200 to 900 rpm, the stirring temperature is 16 to 50° C., and the centrifugation condition is 10,000 rpm for 15 minutes, so as to remove the water-insoluble curcumin.

[0014] Structural characterization, including infrared spectroscopy, of the curcumin-flavored low-sodium salt prepared by the above method revealed that the aromatic rings on both sides of the curcumin molecule are encapsulated within the γ-cyclodextrin, with sodium chloride attached to the surface of the complex. This binding pattern increases the specific surface area of ​​sodium chloride, thereby increasing its release rate from solution. Compared to sodium chloride, the perceived saltiness of the curcumin-flavored low-sodium salt was 2.16 times stronger and the perceived bitterness was 1.38 times weaker.

[0015] The curcumin flavored low sodium salt is used in food seasonings and food processing.

[0016] The aforementioned low-sodium curcumin flavor salt is used in the preparation of DPPH scavenging products. The retention rate of the curcumin under various stress conditions ranges from 25% to 92%. Due to the antioxidant activity of curcumin, the DPPH scavenging rate of 2 mg / mL of the low-sodium curcumin flavor salt can reach 40%.

[0017] The above-mentioned curcumin-flavored low-sodium salt is used in the preparation of antibacterial products. When the curcumin content is 30 μg / ml, the curcumin-flavored low-sodium salt can effectively inactivate Shewanella putrefaciens and Vibrio parahaemolyticus under the action of ultrasound and a 420-425 nm wavelength light source, with sterilization rates reaching 99.9% and over 90%, respectively. The reasons for the effective inactivation of harmful microorganisms by curcumin-flavored low-sodium salt are: 1) Curcumin, as an acoustic-photosensitizer, undergoes electronic transitions under the action of a specific excitation wavelength light source and ultrasonic radiation. Through energy transfer, it generates a series of reactive oxygen species, which act on microbial cells. 2) The presence of sodium chloride (at an ineffective antibacterial concentration) enhances the sensitivity of microbial cells to curcumin and the reactive oxygen species it generates.

[0018] The beneficial effects of the present invention are:

[0019] The low-sodium curcumin flavored salt prepared by the present invention is simple to produce, exhibits excellent appearance, antioxidant capacity, and bactericidal properties, and has a fatty and vanilla flavor, with a stronger salty taste than traditional sodium chloride. The low-sodium curcumin flavored salt prepared by the present invention is not a simple physical mixture. Structural characterization results, such as infrared spectroscopy, suggest that the aromatic rings on both sides of the curcumin molecule are encapsulated within γ-cyclodextrin, with sodium chloride attached to the surface of the complex. Gas chromatography ion mobility spectrometry analysis revealed characteristic volatile flavor compounds, including octanal, heptanal, trans-2-heptenal, 2-hexenal, valeraldehyde, nonanal, 2-ethylhexanol, hexanol, octanol, heptanol, 6-methyl-50-hepten-2-one, and 2-pentylfuran. Description of the drawings:

[0020] Figure 1 Preparation and image of curcumin flavored low-sodium salt. A) Image of curcumin flavored low-sodium salt; B-D) Effects of different γ-cyclodextrin inclusion conditions on curcumin.

[0021] Figure 2 Infrared spectrum (A), scanning electron microscopy (B) and energy spectrum analysis (C) of curcumin flavored low sodium salt.

[0022] Figure 3 The effect of curcumin flavored low sodium salt on the acousto-photodynamic inactivation of Shewanella putrefaciens (A) and Vibrio parahaemolyticus 6 (C).

[0023] Figure 4DPPH free radical scavenging ability (A, B), light stability (C: UV; D: sunlight) and thermal stability (E: 50℃; F: 80℃) of curcumin compound flavored edible salt

[0024] Figure 5 This paper conducts volatile substance analysis and taste analysis of curcumin compound flavored edible salt. Specific implementation method:

[0025] The present invention provides a low-sodium curcumin flavored salt and its preparation method. In this low-sodium curcumin salt, the aromatic rings on both sides of the curcumin molecule are encapsulated within γ-cyclodextrin, with sodium chloride attached to the surface of the complex. This low-sodium curcumin salt exhibits excellent appearance, antioxidant and bactericidal properties, and offers both fatty and vanilla flavors, as well as a stronger salty taste compared to traditional sodium chloride.

[0026] The present invention discloses a curcumin flavored low sodium salt and a preparation method thereof. Those skilled in the art can refer to the contents of this article and appropriately improve the process parameters to achieve the desired effect. Unless otherwise specified, the raw materials used in the present invention are all purchased from the market. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The products and methods of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0027] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to specific embodiments.

[0028] Example 1

[0029] 37 mg of curcumin was dissolved in 4 mL of anhydrous ethanol, and curcumin, γ-cyclodextrin, and sodium chloride were mixed in a mass ratio of 37:130:500. The curcumin content in the supernatant was calculated under the conditions of stirring time (0, 6, 12, 24, 48 h), stirring speed (0, 200, 300, 600, 800 rpm), and temperature (16, 25, 30, 40, 50 h).

[0030] Figure 1 The experimental results in this study showed that the inclusion capacity of γ-cyclodextrin for curcumin gradually increased with increasing stirring time, stirring speed, and stirring temperature. The optimal parameters were: stirring time of 24 hours, stirring speed of 900 rpm, and temperature of 50°C. Under the optimal preparation conditions in this experiment, the solubility of curcumin in aqueous solution was 0.015 mg / mL.

[0031] Example 2

[0032] The prepared curcumin flavored low-sodium salt was structurally characterized. Fourier transform infrared spectroscopy (FTIR) spectroscopy was performed: Potassium bromide was oven-dried at 110°C for at least 6 hours. The sample (curcumin, γ-cyclodextrin, sodium chloride, a physical mixture of the three, curcumin flavored low-sodium salt (complex), or curcumin-γ-cyclodextrin complex) was then pounded with the dried potassium bromide in a quartz mortar at a ratio of 1:4. Thin slices were then formed and scanned 32 times over a range of 400-400 cm⁻¹ at a resolution of 4 cm⁻¹. Scanning electron microscopy and energy dispersive spectroscopy (EDS) analysis were performed: A small amount of sample powder was adhered to carbon tape on a sample pin and then gold-sprayed. Micromorphology and EDS analysis were then performed under a scanning electron microscope (SEM).

[0033] The structure of the prepared composite salt was characterized. In the curcumin flavored low sodium salt, curcumin was -1 and 1602cm -1 The characteristic absorption peaks of phenol hydroxyl group and benzene ring stretching vibration disappeared, which are located at 1509cm -1 The characteristic peak at 1513 cm -1 , which corresponds to the bending vibration of the C=O bond. In addition, the peak at 3357cm belongs to γ-cyclodextrin. -1 and 2927cm -1 The characteristic absorption peaks at 3379 cm -1 and 2931cm -1 . This shows that the aromatic ring of curcumin forms a complex with γ-cyclodextrin and sodium chloride through interaction, indicating that curcumin flavored low-sodium salt has been successfully prepared. Subsequently, we further analyzed the microscopic morphology and surface element distribution of curcumin flavored low-sodium salt with the help of scanning electron microscopy and energy spectrum. The results are shown in Figures A and B. The results show that curcumin flavored low-sodium salt is irregular solid particles with an amorphous structure, and sodium and chlorine elements are distributed on the surface of the composite salt particles.

[0034] Example 3

[0035] The antioxidant capacity of curcumin flavored low-sodium salt was determined using a DPPH radical scavenging assay. Curcumin and ascorbic acid were prepared at concentrations of 0, 5, 10, 15, and 20 μg / mL, while curcumin flavored low-sodium salt was prepared at concentrations of 0, 0.5, 1.0, 1.5, and 2.0 μg / mL. The assay was performed according to the kit instructions, and the absorbance of the reaction solution at 517 nm was measured. Ascorbic acid served as a positive control, and ultrapure water served as a blank control. Curcumin and curcumin flavored low-sodium salt were incubated at 50°C and 80°C under stress conditions of darkness, natural light, and UV irradiation. The UV absorbance at 425 nm was measured for 0 to 6 hours to analyze the thermal and photostability of curcumin flavored low-sodium salt.

[0036] The results of the examples show that the curcumin flavored salt exhibits excellent stability under stress conditions such as darkness, ultraviolet light, natural light, and temperatures of 30°C, 50°C, and 80°C, with curcumin retention ranging from 25% to 92%. Furthermore, the curcumin flavored low-sodium salt exhibits excellent antioxidant capacity, with a DPPH scavenging rate of 40% at a concentration of 2 mg / mL.

[0037] Example 4

[0038] The prepared curcumin-flavored low-sodium salt was subjected to acoustodynamic antibacterial analysis. Using Shewanella putrefaciens and Vibrio parahaemolyticus as model strains, a third-generation bacterial suspension was centrifuged at 4000 rpm for 5 minutes and resuspended in sterile PBS. The resuspension was then mixed with a 1:1 solution of curcumin-flavored low-sodium salt solution to achieve curcumin concentrations of 10 μg / mL and 30 μg / mL. After incubation in the dark for 30 minutes, the suspension was placed in an acoustodynamic reaction device for 30 minutes. The total bacterial count was then determined using the dilution coating method.

[0039] The results of this example show that the total colony counts of Shewanella putrefaciens and Vibrio parahaemolyticus decreased by 3.06 and 1.44 logarithms, respectively, under the acousto-photodynamic treatment mediated by 30 μg / mL curcumin flavored low sodium salt. The results suggest that curcumin flavored low sodium salt can mediate acousto-photodynamic inactivation of Shewanella putrefaciens and Vibrio parahaemolyticus.

[0040] Example 5

[0041] Characteristic volatile substance analysis: GC-IMS was used to determine the characteristic volatile substances of curcumin flavor low sodium salt. A 3% solution of curcumin flavor low sodium salt, curcumin cyclodextrin complex, γ-cyclodextrin, sodium chloride, and curcumin was prepared, and then the conditions in Example 4 were referred to for acousto-photodynamic treatment. 8 mL of the sample solution before and after treatment was transferred to a brown headspace bottle and tested on the machine. Test conditions: incubation temperature 50°C; syringe 1 mL; time 25 min. Characteristic taste analysis: Characteristic taste analysis was performed using a taste analysis system. A 3% solution of curcumin flavor low sodium salt, curcumin cyclodextrin complex, γ-cyclodextrin, sodium chloride, and curcumin was prepared, and then the conditions in Example 4 were referred to for acousto-photodynamic treatment. The reaction sample solution was then tested on the machine.

[0042] As shown in the GC-IMS fingerprint, sodium chloride and cyclodextrin themselves lack characteristic flavors. However, the volatile compounds of curcumin, curcumin-cyclodextrin complex (CC), and curcumin-cyclodextrin-sodium chloride complex (IC) exhibit both similarities and differences. Their characteristic flavors are primarily characterized by pleasant aromas such as fat and vanilla. Curcumin complex (IC) has a similar flavor profile to sodium chloride; compared to sodium chloride, the salty taste is enhanced and the bitterness response is reduced. This suggests that curcumin complex salt could serve as a promising low-sodium salt substitute.

[0043] In summary, the present invention provides a curcumin flavored low-sodium salt and its preparation method. This research has determined the preparation conditions for the curcumin flavored low-sodium salt and clarified the formation mechanism of the curcumin flavored low-sodium salt: the aromatic rings on both sides of the curcumin molecule are encapsulated within γ-cyclodextrin, with sodium chloride attached to the surface of the complex. The functions and characteristic flavors of the curcumin flavored low-sodium salt are also analyzed: the curcumin flavored low-sodium salt has excellent antioxidant capacity and stability, a pleasant fatty and vanilla flavor, a stronger salty taste and lower bitterness than sodium chloride, and can mediate the acousto-photodynamic inactivation of Shewanella putrefaciens and Vibrio parahaemolyticus.

[0044] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing curcumin flavored low sodium salt, characterized in that The following steps are involved: (1) dissolving curcumin in anhydrous ethanol to obtain a curcumin stock solution; the concentration of the curcumin stock solution is 10 mg / mL; (2) Dissolving γ-cyclodextrin and sodium chloride in pure water, and then dissolving the curcumin stock solution in the step (1) in a proportion in the mixed aqueous solution of γ-cyclodextrin and sodium chloride, stirring continuously for a period of time, centrifuging and discarding the precipitate, and freeze-drying the supernatant to obtain curcumin low sodium salt; wherein the volume ratio of the γ-cyclodextrin and sodium chloride mixed solution to the curcumin stock solution is 25:4; the curcumin:γ-cyclodextrin:sodium chloride is mixed in a mass ratio of 37:130:500; the stirring time is 6 to 48 hours, the stirring speed is 200 to 900 rpm, the stirring temperature is 16 to 50°C, and the centrifugation conditions are: 10000 rpm, 15 minutes.

2. The curcumin flavored low sodium salt prepared by the method according to claim 1, the infrared spectroscopy structural characterization results show that the aromatic rings on both sides of the curcumin molecule are included in the interior of γ-cyclodextrin, and sodium chloride is attached to the surface of the complex.

3. Application of the curcumin flavored low sodium salt according to claim 2 in food seasonings and food processing.

4. Use of the curcumin flavored low sodium salt according to claim 2 in the preparation of DPPH scavenging products.

5. Use of the curcumin flavored low sodium salt according to claim 2 in the preparation of antibacterial products.

Images