Cinnamon essential oil emulsion as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of emulsion preparation, and particularly relates to cinnamon essential oil emulsion as well as a preparation method and application thereof. The cassia bark essential oil emulsion is prepared by jointly emulsifying cassia bark essential oil by utilizing a Chinese honeylocust fruit water extract and soybean protein isolate. The production process is simple, the production cost is low, large-scale production is facilitated, and the prepared cinnamon essential oil emulsion has good storage stability at the temperature of 4 DEG C and also shows excellent electrolyte, pH value, temperature and freeze-thaw stability. The method is suitable for the fields of food, packaging materials, medicines and the like, and the preservation capacity of the prepared cinnamon essential oil emulsion can be comparable with that of a commercial food preservative potassium sorbate.

Description

Technical Field

[0001] The invention belongs to the technical field of emulsion preparation, and more specifically, relates to a cinnamon essential oil emulsion and a preparation method and application thereof. Background Art

[0002] In recent years, due to consumers' negative views on chemical preservatives, the use of natural plant extracts in the food industry as a safe and effective antibacterial preservation technology has received considerable attention. Among them, cinnamon essential oil has good antibacterial activity and has been used as an antibacterial agent in food. However, cinnamon essential oil has defects such as low water solubility, high volatility, irritation, and instability under changes in light, temperature and humidity. The hydrophobicity and environmental instability of cinnamon essential oil pose a huge challenge to its direct incorporation into food and beverage products, limiting its practical application. In order to maintain the biological activity of cinnamon essential oil and at the same time minimize the impact on the sensory properties of the incorporated food, cinnamon essential oil needs to be emulsified and encapsulated in a delivery system compatible with food applications.

[0004] However, many chemical synthetic emulsifiers show low biodegradability and cytotoxicity to various organisms, including humans. In addition, studies have shown that chemical synthetic emulsifiers used in food pose a threat to human health, such as Tween 80 and carboxymethyl cellulose, which play a key role in the occurrence of intestinal inflammatory processes, such as irritable bowel syndrome and metabolic syndrome, as well as chronic diseases such as obesity. Given consumers' demand for green and safe products, natural emulsifiers have become a strong candidate for partial or complete replacement of chemical synthetic emulsifiers.

[0005] Gleditsia sinensis is rich in polysaccharides, proteins and saponins and has been used in traditional medicine. Its main bioactive component, galactomannan, has antioxidant, hypoglycemic and hypolipidemic properties. By adopting microwave-assisted extraction technology, Gleditsia sinensis water extract can be obtained with low energy consumption and low pollution, showing great potential in the field of food emulsification. Nevertheless, the use of Gleditsia sinensis water extract alone as an emulsifier has certain limitations, especially in terms of formulation stability.

[0006] Soy protein isolate is the most important commercial soy protein product. Due to its amphiphilicity, soy protein isolate has good adsorption ability on the oil-water interface and reduces the interfacial tension through a thick protective layer, so it can be used as an effective emulsifier to stabilize the emulsion. However, the emulsion prepared by soy protein isolate is sensitive to environmental conditions (such as pH, electrolytes, temperature, etc.) and is easily affected by environmental conditions, resulting in instability. Its application as a food emulsifier and in food production and processing is still limited. Summary of the invention

[0007] The technical problem to be solved by the invention is to overcome the defects and shortcomings of the prior art and provide a preparation method of cinnamon essential oil emulsion.

[0008] The purpose of the invention is to provide a cinnamon essential oil emulsion prepared by the preparation method.

[0009] Another object of the present invention is to provide application of the cinnamon essential oil emulsion in food preservation.

[0010] Another object of the present invention is to provide a bacteriostatic agent.

[0011] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0012] The present invention provides a method for preparing a cinnamon essential oil emulsion, comprising the following steps:

[0013] S1. Take sapodilla rice water extract, soy protein isolate and water and mix, hydrate, to obtain sapodilla rice water extract - soy protein isolate emulsion stabilizer;

[0014] S2. The sapodilla rice water extract obtained in S1 - soy protein isolate emulsion stabilizer and cinnamon essential oil are mixed in a volume ratio of 7 to 9: 1 to 3 to obtain a cinnamon essential oil emulsion;

[0015] Wherein, the mass ratio of the sapodilla rice water extract to the soy protein isolate is 1-4:1-2.

[0016] The inventors have found through research that combining sapodilla rice water extract with soy protein isolate to emulsify cinnamon essential oil can significantly improve the storage stability, freeze-thaw stability, pH stability, temperature stability and electrolyte stability of cinnamon essential oil, and the effect is better than the emulsification effect of sapodilla rice water extract or soy protein isolate on cinnamon essential oil alone, and has a synergistic effect.

[0017] Preferably, the mass ratio of the sapodilla rice water extract to the soy protein isolate is 0.5 to 3: 1. Preferably, the mass ratio of the sapodilla rice water extract to the soy protein isolate is 1 to 2: 1.

[0018] Preferably, the concentration of the Gleditsia sinensis water extract is 0.01-0.04 g / mL, and the concentration of the soy protein isolate is 0.01-0.02 g / mL.

[0019] Preferably, in step S1, the mixing method is: heating and stirring at 60-70°C.

[0020] Preferably, the hydration method is: placing at 0-4°C for 12-24 hours.

[0021] Preferably, in step S2, the specific operation of mixing is shearing, and the shearing speed is 8000-10000 rpm.

[0022] Preferably, the shearing time is 1 to 3 minutes. In the shearing process of the present invention, after shearing for 1 minute, it is necessary to stop for 1 minute and then continue shearing.

[0023] In the present invention, the sapodilla rice water extract can be commercially available or homemade.

[0024] Preferably, the present invention provides a method for preparing a sapodilla rice water extract as a reference, the method for preparing a sapodilla rice water extract comprising: mixing sapodilla rice and water in a ratio of 1:90-110, soaking at 40-50° C., microwave treatment, and post-treatment to obtain the sapodilla rice water extract.

[0025] Preferably, the soaking time is 10 to 14 hours.

[0026] Preferably, the microwave treatment time is 30 to 90 seconds.

[0027] Preferably, the power of the microwave treatment is 800-1000w.

[0028] Preferably, the post-treatment is filtering the filtrate, rotary evaporating, and freeze-drying.

[0029] Additionally, the present invention protects the cinnamon essential oil emulsion prepared by the preparation method.

[0030] Furthermore, the present invention also protects the use of the cinnamon essential oil emulsion in food preservation.

[0031] The inventors have found that the cinnamon essential oil emulsion prepared by the present invention has good DPPH and ABTS free radical scavenging ability, good antioxidant effect, and excellent antibacterial effect, and can be used as a food preservative for food preservation.

[0032] Furthermore, the present invention also provides an antibacterial agent, which contains the cinnamon essential oil emulsion of the present invention.

[0033] Preferably, the antibacterial agent inhibits the growth of Staphylococcus aureus and Listeria monocytogenes.

[0034] The inventors have found through research that the cinnamon essential oil emulsion prepared by the present invention has a significant and long-lasting antibacterial effect on Staphylococcus aureus and Listeria monocytogenes.

[0035] The present invention has the following beneficial effects:

[0036] (1) The present invention uses natural products (water extract of sapodilla rice and soy protein isolate) to stabilize cinnamon essential oil to prepare cinnamon essential oil emulsion. The preparation method is green, safe and effective, can exert various pharmacological effects of cinnamon essential oil in a long-lasting and stable manner without toxic side effects, and is suitable for the fields of medicine, aromatherapy, food, health products, cosmetics, etc.

[0037] (2) The present invention utilizes sapodilla rice water extract and soy protein isolate to disperse cinnamon essential oil into O / W (oil-in-water) small emulsion droplets with an average particle size of less than 10 μm, thereby increasing the solubility of cinnamon essential oil, solving the problem that cinnamon essential oil is difficult to dissolve in water, and improving its stability and tissue permeability of efficacy.

[0038] (3) The cinnamon essential oil emulsion prepared by the present invention has good storage stability at 4°C, and also performs well in terms of electrolyte, pH value, temperature and freeze-thaw stability.

[0039] (4) The cinnamon essential oil emulsion prepared by the present invention has good antioxidant and antibacterial abilities and can be used as a preservative in food preservation. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 G' and G" rheological properties of cinnamon essential oil emulsion.

[0041] Figure 2 This is the appearance of cinnamon essential oil emulsion stored at 4°C for 20 days.

[0042] Figure 3 The microstructure and particle size of cinnamon essential oil emulsion stored at 4°C for 20 days.

[0043] Figure 4 This is the appearance of cinnamon essential oil lotion after one freeze-thaw cycle.

[0044] Figure 5 The microstructure and particle size of cinnamon essential oil emulsion after one freeze-thaw cycle.

[0045] Figure 6 The appearance of the soapberry rice water extract-soybean protein isolate cinnamon essential oil emulsion under the influence of different pH values; from left to right, they are pH 3.0, 5.0, 7.0, 9.0, and 11.0.

[0046] Figure 7 The microstructure and particle size of saponin rice water extract-soybean protein isolate cinnamon essential oil emulsion under the influence of different pH values.

[0047] Figure 8 This is the appearance of the soapberry rice water extract-soybean protein isolate cinnamon essential oil emulsion under the influence of different temperatures; from left to right, the temperatures are 20, 50, 60, and 70°C.

[0048] Fig. 9 The microstructure and particle size of saponin rice water extract-soybean protein isolate cinnamon essential oil emulsion under the influence of different temperatures.

[0049] Fig.10This is the appearance of the soapberry rice water extract-soybean protein isolate cinnamon essential oil emulsion under the influence of different electrolyte strengths; from left to right, the NaCl concentrations are 100, 200, 300, 500, and 1000 mM.

[0050] Fig.11 The microstructure and particle size of saponin rice water extract-soybean protein isolate cinnamon essential oil emulsion under the influence of different electrolyte strengths.

[0051] Fig.12 This is a graph showing the DPPH free radical scavenging ability of cinnamon essential oil emulsion.

[0052] Fig.13 This is a graph showing the ABTS free radical scavenging ability of cinnamon essential oil emulsion.

[0053] Fig.14 This is a graph showing the growth inhibition of Listeria monocytogenes by cinnamon essential oil emulsions at different concentrations.

[0054] Fig.15 This is a graph showing the growth inhibition of Staphylococcus aureus by cinnamon essential oil emulsions of different concentrations.

[0055] Fig.16 This is a graph showing the effect of different concentrations of cinnamon essential oil emulsion on the growth curve of Listeria monocytogenes.

[0056] Fig.17 This is a graph showing the effect of different concentrations of cinnamon essential oil emulsion on the growth curve of Staphylococcus aureus.

[0057] Fig.18 This is a graph showing the changes in colony count during the orange juice preservation process.

[0058] Fig.19 A diagram of odor changes detected by an electronic nose during the orange juice preservation process.

[0059] Fig. 20 Principal component analysis (PCA) plot of odor changes detected by the electronic nose during the orange juice preservation process. DETAILED DESCRIPTION

[0060] The present invention is further described below in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0061] Unless otherwise specified, the room temperature in the embodiments of the present invention is 25±2°C.

[0062] The cinnamon essential oil used in the embodiments of the present invention was purchased from Guangzhou Xiangsi Xinqing Health Technology Co., Ltd.

[0063] The sapodilla rice water extract of the examples of the present invention and the comparative examples was prepared according to the following method:

[0064] After the soapberry rice is crushed, it is sieved with a 40-60 mesh screen to obtain soapberry rice powder;

[0065] Mix sapodilla rice powder and deionized water at a ratio of 1:100 and soak at 45°C for 12 h;

[0066] After soaking for 12 hours, use 1000W microwave heating to assist extraction for 60 seconds, then filter the filtrate, rotary evaporate, and freeze-dry to obtain the saponin rice water extract.

[0067] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0068] Example 1

[0069] (1) Weigh 0.1 g of soy protein isolate and 0.1 g of sapodilla rice water extract, dissolve in 10 mL of deionized water, heat and stir at 65° C. until uniform, and place in a refrigerator at 4° C. for 12 h to obtain a sapodilla rice water extract-soy protein isolate emulsion stabilizer;

[0070] (2) Weigh 9 g of sapodilla rice water extract-soybean protein isolate emulsion stabilizer and mix it with 1 g of cinnamon essential oil, use a high-speed shearing machine to shear, the shearing speed is 9000 rpm, stop for 1 min after each shearing for 1 min, and repeat the shearing 3 times to obtain sapodilla rice water extract-soybean protein isolate cinnamon essential oil emulsion.

[0071] Example 2

[0072] (1) Weigh 0.1 g of soy protein isolate and 0.2 g of sapodilla rice water extract, dissolve in 10 mL of deionized water, heat and stir at 65° C. until uniform, and place in a refrigerator at 4° C. for 12 h to obtain a sapodilla rice water extract-soy protein isolate emulsion stabilizer;

[0073] Weigh 9 g of sapodilla rice water extract-soybean protein isolate emulsion stabilizer and mix it with 1 g of cinnamon essential oil, use a high-speed shearing machine to shear, the shearing speed is 9000 rpm, stop for 1 min after each shearing for 1 min, and repeat the shearing 3 times to obtain sapodilla rice water extract-soybean protein isolate cinnamon essential oil emulsion.

[0074] Example 3

[0075] (1) Weigh 0.1 g of soy protein isolate and 0.3 g of sapodilla rice water extract, dissolve in 10 mL of deionized water, heat and stir at 65° C. until uniform, and place in a refrigerator at 4° C. for 12 h to obtain a sapodilla rice water extract-soy protein isolate emulsion stabilizer;

[0076] (2) Weigh 9 g of sapodilla rice water extract-soybean protein isolate emulsion stabilizer and mix it with 1 g of cinnamon essential oil, use a high-speed shearing machine to shear, the shearing speed is 9000 rpm, stop for 1 min after each shearing for 1 min, and repeat the shearing 3 times to obtain sapodilla rice water extract-soybean protein isolate cinnamon essential oil emulsion.

[0077] Example 4

[0078] (1) Weigh 0.2 g of soy protein isolate and 0.1 g of sapodilla rice water extract and dissolve them in 10 mL of deionized water, heat and stir at 65° C. until uniform, and place in a refrigerator at 4° C. for 12 h to obtain a sapodilla rice water extract-soy protein isolate emulsion stabilizer;

[0079] (2) Weigh 9 g of sapodilla rice water extract-soybean protein isolate emulsion stabilizer and mix it with 1 g of cinnamon essential oil, use a high-speed shearing machine to shear, the shearing speed is 9000 rpm, stop for 1 min after each shearing for 1 min, and repeat the shearing 3 times to obtain sapodilla rice water extract-soybean protein isolate cinnamon essential oil emulsion.

[0080] Example 5

[0081] (1) Weigh 0.2 g of soy protein isolate and 0.2 g of sapodilla rice water extract, dissolve in 10 mL of deionized water, heat and stir at 65° C. until uniform, and place in a refrigerator at 4° C. for 12 h to obtain a sapodilla rice water extract-soy protein isolate emulsion stabilizer;

[0082] (2) Weigh 9 g of sapodilla rice water extract-soybean protein isolate emulsion stabilizer and mix it with 1 g of cinnamon essential oil, use a high-speed shearing machine to shear, the shearing speed is 9000 rpm, stop for 1 min after each shearing for 1 min, and repeat the shearing 3 times to obtain sapodilla rice water extract-soybean protein isolate cinnamon essential oil emulsion.

[0083] Example 6

[0084] (1) Weigh 0.2 g of soy protein isolate and 0.3 g of sapodilla rice water extract and dissolve them in 10 mL of deionized water, heat and stir at 65° C. until uniform, and place in a refrigerator at 4° C. for 12 h to obtain a sapodilla rice water extract-soy protein isolate emulsion stabilizer;

[0085] (2) Weigh 9 g of sapodilla rice water extract-soybean protein isolate emulsion stabilizer and mix it with 1 g of cinnamon essential oil, use a high-speed shearing machine to shear, the shearing speed is 9000 rpm, stop for 1 min after each shearing for 1 min, and repeat the shearing 3 times to obtain sapodilla rice water extract-soybean protein isolate cinnamon essential oil emulsion.

[0086] Example 7

[0087] (1) Weigh 0.2 g of soy protein isolate and 0.4 g of sapodilla rice water extract, dissolve in 10 mL of deionized water, heat and stir at 65° C. until uniform, and place in a refrigerator at 4° C. for 12 h to obtain a sapodilla rice water extract-soy protein isolate emulsion stabilizer;

[0088] (2) Weigh 9 g of sapodilla rice water extract-soybean protein isolate emulsion stabilizer and mix it with 1 g of cinnamon essential oil, use a high-speed shearing machine to shear, the shearing speed is 9000 rpm, stop for 1 min after each shearing for 1 min, and repeat the shearing 3 times to obtain sapodilla rice water extract-soybean protein isolate cinnamon essential oil emulsion.

[0089] Comparative Example 1

[0090] (1) Weigh 0.3 g of soy protein isolate and dissolve it in 10 mL of deionized water, heat and stir at 65° C. until it becomes uniform, and place it in a refrigerator at 4° C. for 12 h to obtain a soy protein isolate emulsion stabilizer;

[0091] (2) Weigh 9 g of soy protein isolate emulsion stabilizer and 1 g of cinnamon essential oil, mix them, and use a high-speed shearing machine to shear at a shearing speed of 9000 rpm. After each shearing for 1 min, stop for 1 min. Repeat the shearing 3 times to obtain a soy protein isolate cinnamon essential oil emulsion.

[0092] Comparative Example 2

[0093] (1) Weigh 0.3 g of sapodilla rice water extract and dissolve it in 10 mL of deionized water, heat and stir at 65° C. until it becomes uniform, and place it in a refrigerator at 4° C. for 12 h to obtain a sapodilla rice water extract emulsion stabilizer;

[0094] (2) Weigh 9 g of sapodilla rice water extract emulsion stabilizer and mix with 1 g of cinnamon essential oil, use a high-speed shearing machine to shear, the shearing speed is 9000 rpm, stop for 1 min after each shearing, and repeat the shearing 3 times to obtain a sapodilla rice water extract cinnamon essential oil emulsion.

[0095] Comparative Example 3

[0096] (1) Weigh 0.2 g of soy protein isolate and dissolve it in 10 mL of deionized water, heat and stir at 65° C. until it becomes uniform, and place it in a refrigerator at 4° C. for 12 h to obtain a soy protein isolate emulsion stabilizer;

[0097] (2) Weigh 9 g of soy protein isolate emulsion stabilizer and 1 g of cinnamon essential oil, mix them, and use a high-speed shearing machine to shear at a shearing speed of 9000 rpm. After each shearing for 1 min, stop for 1 min. Repeat the shearing 3 times to obtain a soy protein isolate cinnamon essential oil emulsion.

[0098] Comparative Example 4

[0099] The difference from Example 6 is that Tween 80 is used to replace the water extract of Gleditsia sinensis, and Span 80 is used to replace the isolated soy protein, so that Tween 80-Span 80 cinnamon essential oil emulsion can be prepared.

[0100] The present invention has conducted a series of investigations on the structural type, microscopic morphology, particle size, stability, functionality, etc. of the cinnamon essential oil emulsions prepared in the embodiments and comparative examples. The following test examples are used to further illustrate the present invention.

[0101] Test Example 1 Rheological Properties

[0102] Experimental materials: cinnamon essential oil emulsions prepared in Examples 4 to 7.

[0103] The rotational rheometer was used to set the scanning frequency to 0.1-100 rad / s and the CP50-1 probe was selected for measurement. Figure 1 As shown, the storage modulus G' of the emulsion is always greater than the loss modulus G", indicating that the emulsion has a three-dimensional network structure.

[0104] Test Example 2 Stability Test

[0105] Microstructure and droplet size detection method of emulsion: take a drop of emulsion and carefully drop it on the slide, cover it with a cover glass, and observe and take pictures with a 10X eyepiece and a 40X objective lens. Use the ImageJ program to measure the droplet size and particle size distribution. 1200 droplets are measured from 10 different points on the microscopic images of 3 emulsions, and the average droplet size of the emulsion is calculated (D32 = ∑nidi 3 / ∑nidi 2 ).

[0106] Storage stability: The cinnamon essential oil emulsions prepared in Examples 1-3 and Comparative Examples 1-2 were stored at 4°C for 20 days, and the appearance of the emulsions was photographed and the microstructure and droplet size of the emulsions were measured. Figure 2 , Figure 3 As shown, the cinnamon essential oil emulsions prepared in Examples 1-3 have good stability, and the droplet size does not change significantly before and after being stored at 4°C for 20 days. Comparative Example 1 and Comparative Example 2 are cinnamon essential oil emulsions stabilized by using soy protein isolate alone and cinnamon essential oil emulsions stabilized by using sapodilla rice water extract alone, respectively. After being stored at 4°C for 20 days, the emulsion in Comparative Example 1 shows stratification, while the emulsion in Comparative Example 2 has oil precipitation, and the droplet size of the emulsion changes greatly before and after storage for 20 days, and the storage stability is poor; at the same dosage, the cinnamon essential oil emulsion Example 2 stabilized by using sapodilla rice water extract and soy protein isolate shows better stability.

[0107] Freeze-thaw stability: Examples 4 to 7 and Comparative Example 3 were placed in a -20°C freezer for 24 hours. The emulsions were then thawed in a 30°C oven for 3 hours. The emulsions were photographed and their microstructure and droplet size were measured. The results are shown in Table 1. Figure 4 , Figure 5 As shown, the cinnamon essential oil emulsions prepared in Examples 4 to 7 have good stability, and their droplet size does not change significantly before and after freeze-thaw stability, and have good freeze-thaw stability. Comparative Example 3 is to prepare cinnamon essential oil emulsion using soy protein isolate alone. The emulsion has stratification and oil separation before and after freeze-thaw, and the droplet size changes greatly, and the freeze-thaw stability is poor.

[0108] pH stability: The pH of Example 6 was adjusted to 3.0, 5.0, 7.0, 9.0, and 11.0 using HCl and NaOH, respectively, and the appearance of the emulsion was photographed and the microstructure and droplet size of the emulsion were measured. Figure 6 , Figure 7 As shown, the cinnamon essential oil emulsion stabilized by the aqueous extract of saponin rice and soy protein isolate did not show stratification, the difference in particle size was not obvious, and it had excellent pH stability.

[0109] Temperature stability: Example 6 was heated in a water bath at 20, 50, 60, and 70°C for 30 minutes and then cooled to room temperature. The appearance of the emulsion was photographed and the microstructure and droplet size of the emulsion were measured. The results are shown in Table 1. Figure 8 , Fig. 9 As shown, under the condition of 20-70°C, the cinnamon essential oil emulsion stabilized by using saponin rice water extract and soy protein isolate did not show stratification, the difference in particle size was not obvious, and it had excellent temperature stability.

[0110] Electrolyte stability: NaCl was added to the sapodilla rice water extract-soy protein isolate cinnamon essential oil emulsion of Example 6, and the NaCl concentration was adjusted to 100, 200, 300, 500, and 1000 mM. The appearance of the emulsion was photographed and the microstructure and droplet size of the emulsion were measured. The results are as follows: Fig.10 , Fig.11 As shown, the cinnamon essential oil emulsion stabilized by saponin rice water extract and soy protein isolate did not show stratification, the difference in particle size was not obvious, and it had excellent electrolyte stability.

[0111] Test Example 3 Antioxidant Activity Test

[0112] Sample: the cinnamon essential oil emulsion prepared in Example 6 or the cinnamon essential oil emulsion prepared in Comparative Example 4.

[0113] Sample solution: Mix the above samples with water to prepare sample solutions of different concentrations.

[0114] Method for determining DPPH free radical scavenging rate: take 500 μL of the prepared 0.1mmol / LDPPH anhydrous ethanol solution and mix it with 500 μL of the sample solution, react in the dark for 15 minutes, centrifuge at 8000 rpm for 15 minutes, take 200 μL of the supernatant and measure the absorbance at 517 nm using an ELISA reader in a 96-well plate, and calculate the DPPH free radical scavenging rate according to formula (1):

[0115]

[0116] Where A0 is the absorbance value of the control group without sample, A1 is the absorbance value of the reaction group, and A2 is the absorbance value of the blank group without DPPH.

[0117] Method for determining ABTS free radical scavenging rate: ABTS (2.45mmol / L) and K2S2O8 (7.0mmol / L) stock solutions were mixed in a ratio of 1:1, reacted in the dark for 16h, and then diluted with PBS buffer (pH=7.4) to make the absorbance value at 734nm between 0.7 and 0.8 to obtain ABTS working solution. 100μL ABTS working solution and 300μL sample solution were placed in a 1mL centrifuge tube to react for 5min in the dark, centrifuged at 8000rpm for 5min, and 200μL of supernatant was taken to a 96-well plate and the absorbance was measured at 734nm using an enzyme reader. The ABTS free radical scavenging rate was calculated according to formula (2):

[0118]

[0119] Where A0 is the absorbance value of the control group without sample, A1 is the absorbance value of the reaction group, and A2 is the absorbance value of the blank group without ABTS.

[0120] The results are as follows Fig.12 , Fig.13 As shown, the cinnamon essential oil emulsion stabilized by the sapodilla rice water extract and soy protein isolate prepared by the embodiment of the present invention has a good ability to scavenge free radicals and good antioxidant performance.

[0121] Test Example 4 Antibacterial Ability Test

[0122] Samples: cinnamon essential oil emulsion prepared in Example 6, cinnamon essential oil emulsion prepared in Comparative Example 4, 10% (w / w) cinnamon essential oil-propylene glycol solution (the mass percentage of cinnamon essential oil in the cinnamon essential oil-propylene glycol solution is 10%).

[0123] The antibacterial properties of cinnamon essential oil emulsion were evaluated using Gram-positive Staphylococcus aureus and Listeria monocytogenes, two food-related microorganisms.

[0124] In the minimum inhibitory concentration (MIC) experiment, the agar plate dilution method was used. The above samples were diluted with sterilized nutrient broth and mixed into the sterilized plate count agar PCA. The final concentrations of the samples in the PCA were 0.52, 1.04, 2.08, 4.16, and 8.33 mg / mL. The bacteria activated three times were centrifuged and enriched, and the bacterial suspension (OD600≈0.4) was prepared with sterile water and spread on the PCA sample plate. Nutrient broth and sterile water were used as blank controls. The culture temperature was 37°C. The lowest concentration without strain growth after 24 hours was considered as MIC. The results are as follows Fig.14 , Fig.15 As shown, the minimum inhibitory concentration (MIC) of the cinnamon essential oil emulsion stabilized by the aqueous extract of Gleditsia sinensis and the isolated soy protein (Example 6) against Listeria monocytogenes and Staphylococcus aureus was 2.08 mg / mL.

[0125] In the growth curve experiment, the sample groups were set as follows: Example 6-MIC0.5 (MIC value * 0.5 (2.08 * 0.5) = 1.04 mg / mL), Example 6-MIC1 (2.08 mg / mL), Example 6-MIC2 (4.16 mg / mL), Example 6-MIC4 (8.32 mg / mL), Comparative Example 4 (2.08 mg / mL), 10% (w / w) cinnamon essential oil-propylene glycol solution (2.08 mg / mL), potassium sorbate (2.08 mg / mL), and the samples were diluted with sterilized nutrient broth to obtain sample culture fluids of corresponding concentrations. 194 μL of sample culture fluid and 4 μL of bacterial solution activated to the logarithmic growth phase were added to a 96-well plate and mixed. Nutrient broth and sterile water were used as blank controls. Using a fully automatic microbial growth curve analyzer, the absorbance at OD600 of the culture fluid was measured every 1 hour.

[0126] The results are as follows Fig.16 , Fig.17 As shown, the cinnamon essential oil emulsion stabilized by the aqueous extract of Gleditsia sinensis and the isolated soy protein (Example 6) has an excellent and lasting inhibitory effect on the growth of Listeria monocytogenes and Staphylococcus aureus; the cinnamon essential oil emulsion prepared in Comparative Example 4 (conventional Tween 80 and Span 80 emulsified cinnamon essential oil) also has a good inhibitory effect on Listeria monocytogenes and Staphylococcus aureus in the early stage of the experiment, but after about 750 minutes, Staphylococcus aureus increased significantly and the inhibitory effect weakened; after about 1500 minutes, Listeria monocytogenes increased significantly and the inhibitory effect weakened. It can be seen that the cinnamon essential oil emulsion prepared in Comparative Example 4 has a poor long-term antibacterial effect.

[0127] Application Example 1: Orange juice preservation

[0128] Peel the fresh oranges purchased from the supermarket and put them into a juicer to squeeze the juice. Pass the juice through a 100-mesh filter cloth and pack the freshly squeezed orange juice into 250 mL blue-capped glass bottles, 200 mL per bottle, and divide them into 6 groups:

[0129] Blank group: orange juice without any treatment;

[0130] Positive control group: potassium sorbate was added to orange juice to a final concentration of 2.08 mg / mL;

[0131] Comparative Example 4: The cinnamon essential oil emulsion prepared in Comparative Example 4 was added to orange juice to a final concentration of 2.08 mg / mL;

[0132] Example 6-MIC1 group: the cinnamon essential oil emulsion prepared in Example 6 was added to orange juice to a final concentration of 2.08 mg / mL;

[0133] Example 6-MIC2 group: the cinnamon essential oil emulsion prepared in Example 6 was added to orange juice to a final concentration of 4.16 mg / mL;

[0134] Example 6-MIC4 group: the cinnamon essential oil emulsion prepared in Example 6 was added to orange juice to a final concentration of 8.32 mg / mL;

[0135] After the above treatment, the orange juice was packaged, pasteurized (75°C, 15 min), stored at room temperature away from light for 20 days, and samples were taken and analyzed regularly in a clean bench.

[0136] Determination of total colony count: After sampling in a clean bench, dilute the orange juice to an appropriate multiple, pipette 1 mL of sample solution and 14 mL of plate count agar PCA, mix well and pour on a plate, incubate at 37°C for 36 hours, count the colony count, and perform three parallel tests. Fig.18 As shown, the cinnamon essential oil emulsion stabilized by the aqueous extract of Gleditsia sinensis and soy protein isolate can inhibit the growth of microorganisms in orange juice to the same extent as the commercial preservative potassium sorbate.

[0137] Electronic nose analysis: After sampling in the clean bench, each group took 5 mL of orange juice into the headspace bottle and used the electronic nose to detect the sample. The detection time was 100 s, and each group was repeated three times. The data were analyzed and processed using Winmuster software. Fig.19 , Fig. 20 As shown, the deviation of the smell of orange juice preserved with preservatives before and after 20 days is small, and the cinnamon essential oil emulsion stabilized by sapodilla rice water extract and soy protein isolate can play a role in the smell of orange juice that is equivalent to the commercial preservative potassium sorbate. The sensitive substances of each sensor of the electronic nose are shown in Table 1.

[0138] Table 1 Sensitive substances of electronic nose sensors

[0139] serial number sensor Sensitive substances S1 W1C Aromatic compounds S2 W5S Nitrogen oxides S3 W3C Ammonia, aromatic molecules S4 W6S Hydride S5 W5C Olefins, aromatics, polar molecules S6 W1S Alkanes S7 W1W Sulfur compounds S8 W2S Alcohols, some aromatic compounds S9 W2W Organic sulfur compounds S10 W3S Alkanes and aliphatics

[0140] The above embodiments are preferred implementation modes of the present invention, but the implementation modes 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 cinnamon essential oil emulsion, characterized in that: The following steps are involved: S1. Take sapodilla rice water extract, soy protein isolate and water and mix, hydrate, to obtain sapodilla rice water extract - soy protein isolate emulsion stabilizer; S2. The sapodilla rice water extract obtained in S1 - soy protein isolate emulsion stabilizer and cinnamon essential oil are mixed in a volume ratio of 7 to 9: 1 to 3, and sheared to obtain a cinnamon essential oil emulsion; Wherein, the mass ratio of the sapodilla rice water extract to the soy protein isolate is 1-4:1-2.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the sapodilla rice water extract to the soy protein isolate is 0.5-3:

1.

3. The preparation method according to claim 1, characterized in that: In step S1, the mixing method is: heating and stirring at 60-70°C.

4. The preparation method according to claim 1, characterized in that: The hydration method is to place the mixture at 0-4°C for 12-24 hours.

5. The preparation method according to claim 1, characterized in that: In step S2, the specific operation of the mixing is shearing, and the shearing speed is 8000-10000 rpm.

6. The preparation method according to claim 1, characterized in that: The preparation method of the sapodilla rice water extract comprises: mixing sapodilla rice and water in a mass ratio of 1:90-110, soaking at 40-50 DEG C, microwave treatment, and post-treatment to obtain the sapodilla rice water extract.

7. The preparation method according to claim 6, characterized in that: The power of the microwave treatment is 800-1000w.

8. The cinnamon essential oil emulsion prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the cinnamon essential oil emulsion according to claim 8 in food preservation.

10. An antibacterial agent, characterized in that Contains the cinnamon essential oil emulsion according to claim 8.

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