Methyl cinnamate nano antiseptic and fresh-keeping agent and its preparation method and use

Abstract

The invention discloses a methyl cinnamate nano antiseptic and fresh-keeping agent and its preparation method and use, and belongs to the field of food antiseptic and fresh-keeping. The preparation method of the methyl cinnamate nano antiseptic and fresh-keeping agent of the present invention comprises the following steps: methyl cinnamate is added to medium chain triglyceride, and fully stirred to obtain a methyl cinnamate solution; Tween 80, chitosan, and glacial acetic acid are added to sterile water, and fully stirred to obtain a chitosan solution; methyl cinnamate solution is added to chitosan solution, and a suspension is obtained by high-speed homogenization; the suspension is subjected to ultrasonic treatment to obtain a methyl cinnamate nano antiseptic and fresh-keeping agent. The methyl cinnamate nano antiseptic and fresh-keeping agent of the present invention can significantly inhibit the growth of common corrupt and pathogenic bacteria in food, prolong the shelf life of food, and improve food safety.

Description

Technical Field

[0001] The invention belongs to the field of food antiseptic and fresh-keeping, and in particular relates to a methyl cinnamate nano antiseptic and fresh-keeping agent, a preparation method and application thereof. Background Art

[0002] As people become more aware of the potential adverse effects of chemical preservatives, it is necessary to explore natural alternatives. Methyl cinnamate has a cherry and balsam aroma, with a cocoa flavor. It is allowed to be used as a food flavoring in my country according to GB-2760-2024. It is used as a fixative in the spice industry and is often used to prepare oriental floral flavors such as carnation, cherry, strawberry and grape. Our research shows that methyl cinnamate has a significant inhibitory effect on a variety of food spoilage and pathogenic bacteria, and has great potential in food preservation and freshness preservation applications. However, methyl cinnamate is insoluble in water, which limits its application in food. Summary of the invention

[0003] In order to solve the problems that methyl cinnamate is insoluble in water and difficult to use in food, and at the same time improve the antibacterial effect of methyl cinnamate, the purpose of the present invention is to provide a preparation method of a methyl cinnamate nano preservative, and the methyl cinnamate nano preservative obtained by the preparation method and the use of the same.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] The present invention provides a method for preparing a methyl cinnamate nano preservative, which comprises the following steps:

[0006] (1) Prepare the following raw materials: chitosan, glacial acetic acid, Tween-80, methyl cinnamate, medium chain triglycerides, and sterile water;

[0007] Preferably, the raw materials are prepared according to the following ratio: chitosan powder 1.5-2g, glacial acetic acid solution 500-1000μL, Tween-801-1.5mL, methyl cinnamate 0.25-0.75g, sterile water 30-100mL;

[0008] (2) adding methyl cinnamate to medium chain triglycerides and stirring thoroughly to obtain a methyl cinnamate solution;

[0009] (3) adding Tween-80, chitosan and glacial acetic acid into sterile water and stirring thoroughly to obtain a chitosan solution;

[0010] (4) adding the methyl cinnamate solution obtained in step (2) to the chitosan solution obtained in step (3), and obtaining a suspension by high-speed homogenization;

[0011] (5) subjecting the suspension obtained in step (4) to ultrasonic treatment to obtain a methyl cinnamate nano preservative.

[0012] Furthermore, in step (1), the raw materials are formulated as follows: 1.75 g chitosan, 625 μL glacial acetic acid, 1.25 mL Tween-80, 0.5 g methyl cinnamate, 1 mL medium chain triglyceride, and 65 mL sterile water.

[0013] Furthermore, in step (2), the stirring condition is 500-1000 rpm for 10-15 hours, preferably 800 rpm for 12 hours.

[0014] Furthermore, in step (3), the stirring condition is 300-700 rpm for 10-15 hours, preferably 600 rpm for 12 hours.

[0015] Furthermore, in step (4), the high-speed homogenization condition is 10000-18000 rpm for 3-5 min, preferably 16000 rpm for 5 min.

[0016] Furthermore, in step (5), the ultrasonic treatment is performed at 400-700W for 5-20min, preferably at 650W for 5min.

[0017] The invention also provides a methyl cinnamate nano preservative obtained by the above-mentioned preparation method.

[0018] The present invention also provides application of the aforementioned methyl cinnamate nano antiseptic and fresh-keeping agent in food antiseptic and fresh-keeping.

[0019] Advantages and beneficial effects of the present invention: the nano antiseptic and fresh-keeping agent of the present invention selects methyl cinnamate with antibacterial effect as the antibacterial agent, and the water solubility of methyl cinnamate is increased by preparing methyl cinnamate into the nano antiseptic and fresh-keeping agent, thereby improving the antibacterial effect of methyl cinnamate, significantly inhibiting the growth of common spoilage and pathogenic bacteria in food, extending the shelf life of food, and improving food safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the particle size distribution diagram of the prepared methyl cinnamate nano preservative.

[0021] Figure 2 This is a confocal microscope image of the prepared methyl cinnamate nano preservative.

[0022] Figure 3 This is the stability diagram of the prepared methyl cinnamate nano preservative.

[0023] Figure 4 This is a diagram showing the antibacterial effect of methyl cinnamate and methyl cinnamate nano preservative on Escherichia coli.

[0024] Figure 5 This is a diagram showing the antibacterial effect of methyl cinnamate and methyl cinnamate nano preservative on Staphylococcus aureus.

[0025] Figure 6 This is a diagram showing the antibacterial effect of methyl cinnamate and methyl cinnamate nano preservative on Bacillus.

[0026] Figure 7 This is a diagram showing the antibacterial effect of methyl cinnamate and methyl cinnamate nano preservative on Shigella.

[0027] Figure 8 This is a graph showing the changes in total colony count of pickled beans and pickled beans with methyl cinnamate nano-preservative stored at 37°C for 3 months. DETAILED DESCRIPTION

[0028] The following examples are used to further illustrate the present invention, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the following examples are conventional means well known to those skilled in the art.

[0029] Example 1

[0030] Preparation of the methyl cinnamate nano antiseptic and fresh-keeping agent of the present invention:

[0031] (1) Prepare the raw materials according to the following ratio: chitosan 1.75 g, glacial acetic acid 625 μL, Tween-80 1.25 mL, methyl cinnamate 0.5 g, medium chain triglyceride 1 mL, and sterile water 65 mL;

[0032] (2) adding 0.5 g of methyl cinnamate to 1 mL of medium chain triglyceride and stirring at 800 rpm for 12 hours to obtain a methyl cinnamate solution;

[0033] (3) 1.25 mL of Tween-80, 1.75 g of chitosan and 625 μL of glacial acetic acid were added to 65 mL of sterile water and stirred at 600 rpm for 12 hours to obtain a chitosan solution;

[0034] (4) adding the methyl cinnamate solution obtained in step (2) to the chitosan solution obtained in step (3), and homogenizing using a high-speed homogenizer at 16000 rpm for 5 min;

[0035] (5) The suspension obtained in step (4) is subjected to 650W ultrasonic treatment for 5 minutes to obtain methyl cinnamate nano preservative.

[0036] The average particle diameter (nm), polydispersity index (PDI) and zeta potential (mV) of the prepared methyl cinnamate nano preservative are shown in the following table. Figure 1 As shown. Figure 1It can be seen that the particle size of the methyl cinnamate nano preservative prepared by the present invention is 165.63±1.33 nm, the polydispersity index is 0.47±0.04, and the Zeta potential is 49.37±3.98 mV.

[0037] The microscopic dispersion state of the prepared methyl cinnamate nano preservative was observed. The methyl cinnamate nano preservative was diluted twice and stained with 1 mg / mL Nile red solution. The dispersion state of the nano preservative was observed using a confocal microscope. Figure 2 The results show that the prepared nano antiseptic and preservative is dispersed more uniformly.

[0038] The particle size, polydispersity index and potential of methyl cinnamate nano preservative were observed for seven consecutive days to evaluate its stability. Figure 3 The results show that the prepared methyl cinnamate nano preservative has good stability.

[0039] According to the above method, nanoemulsion cannot be prepared without adding medium chain triglycerides.

[0040] According to the above method, blank chitosan nanoemulsion was prepared without adding methyl cinnamate as a control.

[0041] Example 2

[0042] Inoculate E. coli ATCC 11775 into LB medium and culture at 37°C overnight. Inoculate the overnight cultured E. coli into fresh medium and culture until the logarithmic growth phase. Centrifuge the culture solution at 6000g for 10 minutes to collect the cells. Use 0.01M PBS to adjust the bacterial concentration to 10 8 CFU / mL. Different amounts of methyl cinnamate and the methyl cinnamate nano preservative prepared in Example 1 were added to the LB medium so that the actual concentrations of methyl cinnamate in the medium were 4.0, 2.0, 1.0, 0.5, 0.25, 0.125 and 0.0625 mg / mL, respectively. At the same time, different amounts of blank chitosan nanoemulsion prepared in Example 1 were added to the LB medium as a control, and Escherichia coli was inoculated and cultured at 37°C and 200rpm constant temperature shaking. Each concentration gradient was repeated 3 times. After culturing for 24 hours, the absorbance was measured at OD600 nm using an ultraviolet spectrophotometer to determine the minimum inhibitory concentration of methyl cinnamate and methyl cinnamate nano preservative against Escherichia coli.

[0043] The remaining bacterial solution was cultured for 48 hours, spread onto the corresponding culture medium plate and cultured for 2-3 days to determine the minimum bactericidal concentration.

[0044] The results showed that blank chitosan nanoemulsion had no significant inhibitory effect on Escherichia coli. Figure 4 As shown. Figure 4 It can be obtained that the minimum inhibitory concentrations of methyl cinnamate and methyl cinnamate nano-preservatives against Escherichia coli are 0.5 mg / mL and 0.25 mg / mL respectively. The minimum bactericidal concentrations of methyl cinnamate and methyl cinnamate nano-preservatives against Escherichia coli are 1 mg / mL and 0.5 mg / mL respectively from the coating plate experiment.

[0045] The results of this embodiment prove that compared with methyl cinnamate, the methyl cinnamate nano preservative prepared by the present invention has a better inhibitory effect on Escherichia coli.

[0046] Example 3

[0047] Same as Example 2, except that the microorganism used is Staphylococcus aureus ATCC 33591.

[0048] The results showed that blank chitosan nanoemulsion had no significant inhibitory effect on Staphylococcus aureus. The inhibitory effect of methyl cinnamate and methyl cinnamate nanopreservative on Staphylococcus aureus was as follows Figure 5 As shown. Figure 5 It can be obtained that the minimum inhibitory concentrations of methyl cinnamate and methyl cinnamate nano-preservatives against Staphylococcus aureus are 1 mg / mL and 0.5 mg / mL, respectively. The minimum bactericidal concentrations of methyl cinnamate and methyl cinnamate nano-preservatives against Staphylococcus aureus are 4 mg / mL and 2 mg / mL, respectively, obtained from the plate coating experiment.

[0049] The results of this embodiment prove that compared with methyl cinnamate, the methyl cinnamate nano preservative prepared by the present invention has a better inhibitory effect on Staphylococcus aureus.

[0050] Example 4

[0051] Same as Example 2, except that the microorganism used is Bacillus ATCC 14579.

[0052] The results showed that blank chitosan nanoemulsion had no significant inhibitory effect on Bacillus. Figure 6 As shown. Figure 6 It can be obtained that the minimum inhibitory concentrations of methyl cinnamate and methyl cinnamate nano-preservatives against Bacillus are 0.5 mg / mL and 0.25 mg / mL respectively. The minimum bactericidal concentrations of methyl cinnamate and methyl cinnamate nano-preservatives against Bacillus are 2 mg / mL and 1 mg / mL respectively from the coating plate experiment.

[0053] The results of this embodiment prove that compared with methyl cinnamate, the methyl cinnamate nano preservative prepared by the present invention has a better inhibitory effect on Bacillus.

[0054] Example 5

[0055] Same as Example 2, except that the microorganism used was Shigella boydii ATCC 9207.

[0056] The results showed that blank chitosan nanoemulsion had no significant inhibitory effect on Shigella boydii. Figure 7 As shown. Figure 7 It can be obtained that the minimum inhibitory concentrations of methyl cinnamate and methyl cinnamate nano-preservatives against Shigella boydii are 0.25 mg / mL and 0.125 mg / mL, respectively. The minimum bactericidal concentrations of methyl cinnamate and methyl cinnamate nano-preservatives against Bacillus are 1 mg / mL and 0.5 mg / mL, respectively, obtained from the plate coating experiment.

[0057] The results of this embodiment prove that compared with methyl cinnamate, the methyl cinnamate nano preservative prepared by the present invention has a better inhibitory effect on Shigella.

[0058] Example 6

[0059] The invention discloses an application of the methyl cinnamate nano antiseptic and fresh-keeping agent prepared by the invention in food antiseptic and fresh-keeping.

[0060] Take 10g of pickled beans, add 1mL of methyl cinnamate nano preservative prepared in Example 1 of the present invention, mix well and place in a fresh-keeping bag. At the same time, take 10g of pickled beans and place in a fresh-keeping bag as a control. The two samples are placed in a 37°C incubator for 3 months. Each sample is measured for the total number of colonies, and the results are as follows: Figure 8 As shown. Figure 8 It can be obtained that pickled beans have obvious microbial contamination after being placed at 37° C. for 3 months, while pickled beans added with the methyl cinnamate nano preservative prepared by the present invention have no microorganisms detected after being placed at 37° C. for 3 months.

[0061] The results of this embodiment prove that the methyl cinnamate nano preservative prepared by the present invention can significantly inhibit the growth of common spoilage and pathogenic bacteria in food, extend the shelf life of food, and improve food safety.

[0062] The above embodiments are only used to help illustrate the present invention. The implementation methods of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a methyl cinnamate nano preservative, characterized in that: The steps include: (1) Prepare the following raw materials: chitosan, glacial acetic acid, Tween-80, methyl cinnamate, medium chain triglycerides, and sterile water; (2) adding methyl cinnamate to medium chain triglycerides and stirring thoroughly to obtain a methyl cinnamate solution; (3) adding Tween-80, chitosan and glacial acetic acid into sterile water and stirring thoroughly to obtain a chitosan solution; (4) adding the methyl cinnamate solution obtained in step (2) to the chitosan solution obtained in step (3), and obtaining a suspension by high-speed homogenization; (5) subjecting the suspension obtained in step (4) to ultrasonic treatment to obtain a methyl cinnamate nano preservative.

2. The method for preparing the methyl cinnamate nano antiseptic and preservative according to claim 1, characterized in that: In step (1), the raw materials are prepared according to the following ratio: 1.5-2 g of chitosan powder, 500-1000 μL of glacial acetic acid solution, 1-1.5 mL of Tween-80, 0.25-0.75 g of methyl cinnamate, and 30-100 mL of sterile water.

3. The method for preparing the methyl cinnamate nano antiseptic and preservative according to claim 1, characterized in that: In step (1), the raw materials are prepared according to the following ratio: 1.75 g chitosan, 625 μL glacial acetic acid, 1.25 mL Tween-80, 0.5 g methyl cinnamate, 1 mL medium chain triglyceride, and 65 mL sterile water.

4. The method for preparing the methyl cinnamate nano antiseptic and preservative according to claim 1, characterized in that: In step (2), the stirring condition is 500-1000 rpm for 10-15 hours.

5. The method for preparing the methyl cinnamate nano antiseptic and preservative according to claim 1, characterized in that: In step (3), the stirring condition is 300-700 rpm for 10-15 hours.

6. The method for preparing the methyl cinnamate nano antiseptic and preservative according to claim 1, characterized in that: In step (4), the high-speed homogenization condition is 10000-18000 rpm for 3-5 min.

7. The method for preparing the methyl cinnamate nano antiseptic and preservative according to claim 1, characterized in that: In step (5), the ultrasonic treatment condition is 400-700W ultrasonic treatment for 5-20min.

8. A methyl cinnamate nano preservative, characterized in that: The method is obtained by the preparation method according to any one of claims 1 to 7.

9. The methyl cinnamate nano preservative according to claim 8, characterized in that: The particle size is 165.63±1.33nm, the polydispersity index is 0.47±0.04, and the Zeta potential is 49.37±3.98mV.

10. Use of the methyl cinnamate nano preservative according to claim 8 or 9 in food preservation.

Images