Natural antibacterial substance composition and application thereof in normal-temperature preservation of prefabricated steamed buns

Abstract

The invention discloses a natural antibacterial substance composition, which is prepared from the following components in percentage by mass: 10.42 percent to 23.26 percent of vitamin C, 6.25 percent to 10.71 percent of aromatic vinegar powder and 69.77 percent to 83.33 percent of green orange powder. According to the application of the fresh-keeping agent in the preservation of the prefabricated steamed buns at the normal temperature, a specific method comprises the following steps: adding 1g of yeast and 2.475-4.320 g of the fresh-keeping agent into every 100g of flour, adding 50mL of water, kneading dough, fermenting for 30 minutes under the conditions that the temperature is 37 DEG C and the relative humidity is 85%, dividing into balls, kneading and forming again, fermenting for 15 minutes for the second time in a fermenting box, steaming for 30 minutes in a steaming box, cooling, and sealing the steamed buns by using a sterile sealing bag. The obtained natural antibacterial substance composition has the antibacterial rate of 90% or above on escherichia coli and staphylococcus aureus, and also has an obvious antibacterial effect on aspergillus niger and penicillium. The natural antibacterial substance combination is added into flour for making the steamed buns, after the steamed buns are sealed and packaged, the shelf life of normal-temperature preservation is prolonged from 3 days to 7-15 days, and the sensory score of the prefabricated steamed buns is improved due to the addition of the natural antibacterial substance combination.

Description

Technical Field

[0001] The invention relates to the technical field of room-temperature fresh-keeping, and in particular to a natural antibacterial substance combination and application thereof in room-temperature fresh-keeping of prefabricated steamed bread. Background Art

[0002] With the continuous improvement of people's living standards and the fast-paced working state, the time for family meal preparation and cooking is constantly compressed, and convenient pre-prepared foods are favored. The development of pre-prepared foods abroad was relatively early, and the penetration rate of pre-prepared foods in the United States and Japan has reached more than 60%. my country's pre-prepared food industry started late, but it has developed rapidly. In 2017, the State Council issued the "Opinions on Accelerating the Supply-Side Structural Reform of Agriculture and Vigorously Developing the Grain Industry Economy", which made specific arrangements for "vigorously promoting the industrialization of staple foods" and proposed to support the industrial production of staple food products such as rice, flour, corn, grains and potatoes. In March 2023, the first domestic staple food pre-prepared food industry base was announced.

[0003] The types of spoilage bacteria in sealed packaged steamed buns are mainly bacteria and molds. Since steamed buns need to undergo heat processing, most of the microorganisms introduced in the raw materials and processing will be basically killed. The bacteria and molds detected in sealed packaged steamed buns come from secondary pollution during the cooling and packaging process of the steamed buns and the raw materials and processing process. Compared with refrigeration and freezing, the preservation of food at room temperature has the advantages of convenience, speed and low energy consumption. Room temperature preservation is an important part of the commercialization of pre-prepared staple foods. Common antibacterial agents usually contain some chemical substances. Long-term excessive intake may cause certain damage to human health. Natural antibacterial substances are usually extracted from the metabolites of animals, plants and microorganisms, with high safety and no toxic side effects.

[0004] Vitamin C, vinegar powder, green orange powder, vitamin E, tea polyphenols, licorice antioxidants, ascorbic acid palmitic acid, etc. are all potential natural antibacterial substances suitable for staple foods. Plant essential oils have a broad-spectrum antibacterial effect and have certain antibacterial activity against Gram-positive bacteria, Gram-negative bacteria and fungi. The relevant research on natural antibacterial substances mainly focuses on the detection and mechanism analysis of their inhibition of microbial growth. There are no reports on the application of natural antibacterial substances in the room temperature preservation of steamed bread.

[0005] By compounding natural antibacterial substances, a new, efficient and safe combination of antibacterial substances with a wider antibacterial spectrum can be obtained. Therefore, the development of vitamin C, vinegar powder and green tangerine powder as prefabricated steamed bread preservatives has broad application prospects in the prefabricated staple food processing industry. Compared with traditional chemical additives, the compounded natural antibacterial substance combination can also enhance the flavor of prefabricated steamed bread, improve the nutritional value and economic value, etc., and is worthy of promotion and application. Summary of the invention

[0006] The present invention aims to solve the above problems. In a first aspect, a natural antibacterial substance combination is provided. The natural antibacterial substance combination comprises the following components by mass fraction: 10.42%-23.26% of vitamin C, 6.25%-10.71% of balsamic vinegar powder, and 69.77%-83.33% of green tangerine powder.

[0007] A further preferred formula 1 is that the natural antibacterial substance combination includes the following components by mass fraction: vitamin C 18.18%, balsamic vinegar powder 9.09%, and green tangerine powder 72.73%.

[0008] A further preferred formula 2 is that the natural antibacterial substance combination includes the following components by mass fraction: vitamin C 23.26%, balsamic vinegar powder 6.98%, and green orange powder 69.77%.

[0009] A further preferred formula three is that the natural antibacterial substance combination includes the following components by mass fraction: vitamin C 17.86%, balsamic vinegar powder 10.71%, and green tangerine powder 71.43%.

[0010] A further preferred formula 4 is that the natural antibacterial substance combination includes the following components by mass fraction: vitamin C 10.42%, balsamic vinegar powder 6.25%, and green tangerine powder 83.33%.

[0011] Based on the above technical solution, the natural antibacterial substance combination also includes cinnamon essential oil.

[0012] In the second aspect, based on the same invention, the present invention also provides the use of a natural antibacterial substance combination as mentioned above in the preservation of pre-made steamed buns at room temperature.

[0013] Furthermore, the method for using the natural antibacterial substance combination is: add 1 g of yeast and 2.475-4.320 g of preservative for every 100 g of flour, add 50 mL of water, knead the dough, and let it rise for 30 minutes at a temperature of 37°C and a relative humidity of 85%, divide the dough and re-knead it into shapes, let it rise again in a proofing box for 15 minutes, steam it in a steamer for 30 minutes, then cool it, and seal the steamed buns with sterile sealed bags.

[0014] Furthermore, the application can significantly extend the shelf life of steamed bread stored at room temperature.

[0015] The present invention has the following advantages / benefits: The present invention aims to develop a natural antibacterial substance combination, and obtains a natural antibacterial substance combination with vitamin C, balsamic vinegar powder and green tangerine powder as main components by detecting the antibacterial effects of multiple potential natural antibacterial substances and then optimizing the ratio through orthogonal experiments.

[0016] The antibacterial rate of the natural antibacterial substance combination against Escherichia coli and Staphylococcus aureus was more than 90%, and it also had obvious antibacterial effects on Aspergillus niger and Penicillium. When the natural antibacterial substance combination was added to the flour for making steamed bread, the shelf life of the steamed bread stored at room temperature was extended from 3 days to 7-15 days after the steamed bread was sealed and packaged, with a significant difference (p<0.05), indicating that the natural antibacterial substance combination extended the shelf life of pre-made steamed bread. The total colony counts of the natural antibacterial substance combination on the 4th and 7th days of storage at room temperature were 2.54 ± 0.06 lg CFU / g and 3.37 ± 0.02 lg CFU / g, respectively, which were significantly lower than the blank control 4.17 ± 0.02 lg CFU / g (4th day) and 6.54 ± 0.01 lg CFU / g (7th day).

[0017] In addition, the addition of the natural antibacterial substance combination improves the sensory score of the prefabricated steamed bread. The ingredients of the natural antibacterial substance combination are all natural and come from food raw materials, without chemical synthetic substances. It is suitable for the room temperature preservation of prefabricated steamed bread, solves the potential hazards caused by the use of chemical synthetic preservatives, and provides a reference for the room temperature preservation of prefabricated staple foods. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0019] Figure 1 : The natural antibacterial substance of the present invention has an inhibitory effect on the growth of corrupt microorganisms.

[0020] Figure 2 : The antibacterial effect of potassium sorbate (A) and cinnamon essential oil (B) of the present invention on Aspergillus niger.

[0021] Figure 3 : The inhibitory effect of the natural antibacterial substance of the present invention on Gram-negative bacteria and Gram-positive bacteria; wherein, (A) VC powder with different added amounts; (B), vinegar powder with different added amounts; (C), green tangerine powder with different added amounts.

[0022] Figure 4 : Photos of the natural antibacterial substance combination of the present invention, wherein: (A) Formula 1; (B) Formula 2; (C) Formula 3; (D) Formula 4.

[0023] Figure 5: The production process of the essential oil sheet of the present invention comprises: (A) a cut filter paper sheet; (B) a paper sheet soaked in cinnamon essential oil; and (C) a drained filter paper sheet.

[0024] Figure 6 : Photos of steamed buns with added natural antibacterial substance combinations of the present invention, wherein (A) steamed buns with added natural antibacterial substance combination formula 1; (B) steamed buns with added natural antibacterial substance combination formula 2; (C) steamed buns with added natural antibacterial substance combination formula 3; (D) steamed buns with added natural antibacterial substance combination formula 4; (E) steamed buns without added antibacterial substances; (F) steamed buns with added polylysine hydrochloride; (GL) steamed buns with added essential oil tablets corresponding to AF respectively. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The following embodiments are only for illustrating the present invention, and are not intended to limit the scope of the present invention in any way. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention. The experimental methods used in the present invention are conventional methods unless otherwise specified. The materials, reagents, etc. used in the present invention, unless otherwise specified, can be obtained from commercial channels. In addition, other terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by those of ordinary skill in the art.

[0026] The experimental materials are shown in Table 1 and Table 2: Table 1: Sources of natural antibacterial substances.

[0027]

[0028] Table 2: Experimental strains. Sources of strain information.

[0029]

[0030] Example 1: Detection of the inhibitory effect of natural antibacterial substances on spoilage microorganisms Under sterile conditions, cryopreserved Escherichia coli, Staphylococcus aureus, and Bacillus subtilis were added to LB medium and activated at 180 r / min and 37°C for 12 h. 0.5 mL of each activated bacterial solution was taken and diluted to 10% with sterile saline. 8CFU / mL. Then put the bacterial suspension into a sterile EP tube and shake it evenly. Similarly, place the frozen Penicillium and Aspergillus niger plates in a sterile environment, add physiological saline to the plates, use a sterile inoculation loop to scrape the spores on the plates into the physiological saline, filter with sterile medical cotton cloth, and adjust the concentration to 10 with physiological saline. 8 CFU / mL. Then put the spore suspension into a sterile EP tube and shake it evenly. Inoculate 1% of the adjusted bacteria and fungi solution into the sterilized LB agar medium cooled to about 45°C and pour it into the plate. Place the sterilized sterile Oxford cup on the solidified plate medium and press lightly to make the Oxford cup fully contact with the medium. Place 3 Oxford cups on each plate.

[0031] According to the maximum addition amount or recommended addition amount of the National Food Safety Standard for Food Additives (GB 2760-2024), the natural antibacterial substance to be tested is dissolved in distilled water to make a liquid medicine. After standing for 1 hour, it is sterilized by filtering with a 0.22 μm filter. Take 200 μL of the liquid medicine to be tested and add it to the Oxford cup in turn. Make 3 parallels for each group of liquid medicines, with an equal volume of sterile distilled water as a negative control and potassium sorbate as a positive control. Place the plate in a biochemical incubator and culture at 37°C for 24-48 hours, and measure the diameter of the antibacterial zone. The diameter of the Oxford cup with a diameter of 7.8 mm used in this test is twice the diameter of 16 mm as the sensitivity standard of this test.

[0032] The results of the Oxford cup antibacterial test are shown in Figure 1 The sensitivity of different spoilage microorganisms to the tested samples is shown in Table 3.

[0033] Figure 1 The experimental results in Table 3 show that VC, balsamic vinegar powder and green tangerine powder have a wide antibacterial spectrum. Among them, VC and balsamic vinegar powder have antibacterial effects on Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Penicillium and Aspergillus niger; green tangerine powder has antibacterial effects on Escherichia coli, Staphylococcus aureus, Penicillium and Aspergillus niger. VE has an inhibitory effect on Aspergillus niger, and tea polyphenols and licorice antioxidants have an inhibitory effect on Bacillus subtilis. The antibacterial effect of ascorbyl palmitate is not obvious. On the Aspergillus niger plate, the diameter of the inhibition zone of cinnamon essential oil is larger than that of potassium sorbate, indicating that its antibacterial effect is stronger ( Figure 2 ), can be used for gas phase inhibition.

[0034] Table 3: Sensitivity of spoilage microorganisms to natural antibacterial substances a .

[0035]

[0036] aAn inhibition zone diameter of less than 8 mm was considered insensitive (-), an inhibition zone diameter of greater than 8 mm and less than 16 mm was considered moderately sensitive (+), and an inhibition zone diameter of greater than 16 mm was considered sensitive (++).

[0037] b Distilled water served as a negative control.

[0038] c Potassium sorbate was used as a positive control.

[0039] Example 2: Single Factor Experiment VC, balsamic vinegar powder and green tangerine powder were sterilized by ultraviolet irradiation for 30 min, and dissolved in sterile distilled water to prepare mother solutions with concentrations of VC 120 mg / mL, balsamic vinegar powder 24 mg / mL and green tangerine powder 300 mg / mL. The VC concentration was diluted to 12.0, 9.0, 6.0, 3.0, and 1.0 mg / mL; the vinegar powder concentration was diluted to 2.4, 2.1, 1.8, 1.5, 1.2, 0.9, and 0.6 mg / mL; and the green tangerine powder concentration was diluted to 30.0, 24.0, 18.0, 12.0, and 6.0 mg / mL.

[0040] Take the prepared bacterial suspension, dilute it 100 times, and add Escherichia coli and Staphylococcus aureus into LB medium under sterile conditions so that the inoculation volume is 10 6 CFU / mL and 10 4 CFU / mL, add the drug solution to LB medium inoculated with different bacterial solutions, place it in a shaker, 180 r / min, 37℃ for 12 h / 24 h, draw 200 μL on the sterile operating table and add it to the ELISA plate, measure the absorbance value at 600 nm with an ELISA reader, do 3 parallel experiments for each group, and take the average value. The control group was inoculated with sterile water.

[0041] Escherichia coli and Staphylococcus aureus are representative strains of Gram-negative bacteria and Gram-positive bacteria, respectively. VC can inhibit the quorum sensing and biofilm formation mechanisms of microorganisms, exposing bacterial cells and making them more susceptible to being killed by VC-induced oxidative stress. Figure 3 As shown in Figure A, the antibacterial effect of VC increased significantly with increasing concentration. When the concentration was 6.0 mg / mL, the antibacterial rate reached about 80%. Vinegar powder contains acetic acid and other organic acids, which can inhibit the growth and reproduction of pathogens by lowering the pH of the microbial growth environment system. Figure 3 As shown in Figure B, when the concentration is 1.8 mg / mL, the antibacterial rate of vinegar powder is about 80%. As the concentration increases, green tangerine powder also shows a certain antibacterial effect, and when the concentration is 18 mg / mL, the antibacterial rate can reach 40%.

[0042] Example 3: Orthogonal experiment The factor level was established based on the single factor results, and the inhibition rate of Escherichia coli or Staphylococcus aureus was used as the evaluation index. According to the L9 (33) orthogonal table, the VC concentration (A), vinegar powder concentration (B), and green orange powder concentration (C) were optimized. The orthogonal test design is shown in Table 4, and the orthogonal test results are shown in Table 5.

[0043] Table 4: Orthogonal experimental design table

[0044] Table 5: Orthogonal experiment results

[0045] Escherichia coli (inoculation size was 10 6 CFU / mL) was used as the target, and the order of influence of each factor on the antibacterial rate was A>C>B, that is, vitamin C> green tangerine powder> vinegar powder. The best ratio of compound antibacterial substances was A1B1C1, that is, vitamin C 3.0 mg / mL, vinegar powder 1.5 mg / mL, green tangerine powder 12.0 mg / mL, and the antibacterial rate was 92.67% ± 0.02%, which was better than other combinations. 4 CFU / mL), Staphylococcus aureus (10 6 CFU / mL), Staphylococcus aureus (10 4 CFU / mL) was used as the target, and the order of influence of each factor on the inhibition rate was A>B>C, that is, vitamin C>vinegar powder>green tangerine powder. The optimal ratios of compound antibacterial substances were A1B2C1 (vitamin C 3.0 mg / mL, vinegar powder 1.8 mg / mL, green tangerine powder 12.0 mg / mL), A2B2C2 (vitamin C 6.0 mg / mL, vinegar powder 1.8 mg / mL, green tangerine powder 18.0 mg / mL), and A1B2C3 (vitamin C 3.0 mg / mL, vinegar powder 1.8 mg / mL, green tangerine powder 24.0 mg / mL), with inhibition rates of 95.33% ± 0.09%, 96.94% ± 0.05%, and 98.74% ± 0.02%, respectively, which were better than other combination conditions.

[0046] The best formula obtained according to the orthogonal experiment results is as follows: Formula 1: Vitamin C 3.0 mg / mL; balsamic vinegar powder 1.5 mg / mL; green tangerine powder 12.0 mg / mL; converted into powder, the mass ratio of the ingredients in the natural antibacterial substance combination is 2:1:8, specifically 18.18% vitamin C, 9.09% balsamic vinegar powder, and 72.73% green tangerine powder.

[0047] Formula 2: Vitamin C 6.0 mg / mL; balsamic vinegar powder 1.8 mg / mL; green tangerine powder 18.0 mg / mL; converted into powder, the mass ratio of the ingredients in the natural antibacterial substance combination is 10:3:30, specifically 23.26% vitamin C, 6.98% balsamic vinegar powder, and 69.77% green tangerine powder.

[0048] Formula 3: Vitamin C 3.0 mg / mL; balsamic vinegar powder 1.8 mg / mL; green tangerine powder 12.0 mg / mL; converted into powder, the mass ratio of the ingredients in the natural antibacterial substance combination is 5:3:20, specifically 17.86% vitamin C, 10.71% balsamic vinegar powder, and 71.43% green tangerine powder.

[0049] Formula 4: Vitamin C 3.0 mg / mL; balsamic vinegar powder 1.8 mg / mL; green tangerine powder 24.0 mg / mL; converted into powder, the mass ratio of the components in the natural antibacterial substance combination is 5:3:40, specifically 10.42% vitamin C, 6.25% balsamic vinegar powder, and 83.33% green tangerine powder.

[0050] Example 4: Effect of natural antibacterial substance combination on the preservation of steamed bread 4.1 Specific method of steamed buns For every 100 g of flour, add 1 g of yeast and 2.475-4.320 g of natural antibacterial substance combination (the specific amount added is shown in Table 6), add 50 mL of water, knead the dough, and place it at 37°C and 85% relative humidity for 30 min. Divide the dough into groups and re-knead them into shapes. Ferment it in a fermentation box for 15 min, steam it in a steamer for 30 min, cool it, and seal it in a sterile sealed bag. Store at room temperature at 25°C. Cut the filter paper into 1 cm*1 cm squares, sterilize it, soak it in cinnamon essential oil for 1 h, remove it and place it on a clean plate to drain ( Figure 5 ). In the essential oil group, cinnamon essential oil tablets were placed in a sterile sealed bag and sealed. The steamed bread without antibacterial substances was used as a blank control, and the steamed bread with polylysine hydrochloride (0.045 g / 100 g flour) was used as a positive control. Each group of experiments was performed 3 times, and the average value was taken as the experimental result.

[0051] Table 6: Addition amount of preservatives per 100 g flour

[0052] Applying a combination of natural antibacterial substances to pre-made steamed bread ( Figure 6 ), to study its effects on the texture characteristics, sensory evaluation and shelf life of prefabricated steamed bread.

[0053] 4.2 Effects of natural antibacterial substances combination on the texture characteristics and sensory evaluation of steamed bread After cooling at room temperature for 1 hour, the sample was cut longitudinally, and the slices were 25 mm. After cooling at room temperature for 1 hour, the steamed bread was cut longitudinally, and each slice was 25 mm. The cut surface was facing up for TPA test. Parameter setting: the probe model is P / 36R, the probe height is 30 mm, the speed before, during and after the test is 1.0 mm / s, 1.0 mm / s, 1.0 mm / s, respectively, the trigger induction force is 5 g, the compression ratio is 80%, the time interval between two compressions is 5s, and the cut surface is facing up to measure the hardness, elasticity and chewiness of the multi-grain steamed bread.

[0054] A sensory evaluation panel consisting of 10 members who had received sensory training conducted a sensory evaluation of the appearance, chewiness, stickiness, elasticity, flavor, internal structure, and color of the steamed buns according to Table 7. The scores of each item were added together to obtain a weighted comprehensive score of the sensory evaluation.

[0055] Table 7: Sensory evaluation scoring criteria for steamed bread

[0056] The texture test results of steamed bread are shown in Table 8. The hardness of steamed bread with polylysine hydrochloride added is significantly higher than that of blank control. This is because the addition of polylysine hydrochloride inhibits the growth and fermentation of yeast, resulting in fewer spaces between steamed breads, smaller dough fermentation in the same time, and higher hardness. Compared with the blank control, the hardness of formula 1, formula 2 and formula 3 is significantly reduced; the elasticity of formula 2, formula 3 and formula 4 is significantly increased; and the chewiness of formula 2 and formula 4 is significantly increased. In terms of adhesion, cohesion and stickiness, except for the effect of formula 3 on cohesion and formula 4 on stickiness, other natural antibacterial substance combinations did not show significant effects.

[0057] The sensory evaluation results of steamed buns are shown in Table 8. Compared with the blank control group, the sensory score of the polylysine hydrochloride group decreased, and the sensory score of the natural antibacterial agent group increased. Among them, Formula 2 had the highest sensory score. This may be because the addition of VC and green orange powder made the steamed buns sweeter and slightly lowered the pH value of the steamed buns, providing a better environment for yeast fermentation, which is consistent with its lower hardness than the blank control.

[0058] Table 8: Texture characteristics and sensory scores of steamed bread samples

[0059] 4.3 Colony count and shelf life of steamed bread stored at room temperature The sealed steamed buns were stored at room temperature of about 25°C. About 5 g of the inner pulp was taken as test samples on the 0th, 7th and 14th days in a sterile operating table. After gradient dilution with sterile saline as the diluent, the total colony count of the samples was determined with reference to GB / T 4789.2-2016 "Determination of total colony count in food microbiological examination".

[0060] The effect of applying the combination of natural antibacterial substances to steamed bread on the number of colonies is shown in Table 9. On day 0, there was no significant difference in the total number of bacteria in each group. On days 7 and 14, the total number of colonies in each combination of natural antibacterial substances was significantly lower than that in the blank control group. On day 14, the total number of colonies in each combination of natural antibacterial substances was significantly lower than that in the polylysine hydrochloride group.

[0061] Table 9: Total colony count of steamed bread during storage at room temperature.

[0062]

[0063] The effect of the combination of natural antibacterial substances on the shelf life of steamed bread is shown in Table 10. The shelf life of steamed bread in the blank control group is 3 days at room temperature, and the positive control group with polylysine hydrochloride added is 7 days. After adding essential oil tablets, the shelf life increases to 5 days and 8 days respectively. The shelf life of steamed bread with the combination of natural antibacterial substances is 13 days, 15 days, 13 days, and 9 days, respectively, which is significantly higher than the blank control group. Among them, the shelf life of formula 2 group is the longest, reaching 15 days, and formula 3 supplemented with essential oil tablets can reach about 16 days.

[0064] Table 10: Shelf life of steamed bread stored at room temperature (days)

[0065] In summary, by testing the antibacterial effect on spoilage microorganisms, natural antibacterial substances with a broad antibacterial spectrum, including vitamin C, balsamic vinegar powder, and green tangerine powder, were screened out. The formula was optimized through orthogonal experiments to obtain a combination of natural antibacterial substances, which can improve the texture characteristics and sensory scores of steamed bread, and can significantly extend the shelf life of steamed bread stored at room temperature. It can be developed into a preservative for prefabricated steamed bread, and has broad application prospects in the prefabricated staple food processing industry.

[0066] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and concept of the present invention, and all these changes or substitutions should fall within the protection scope of the claims attached to the present invention.

Claims

1. A natural antibacterial substance combination, characterized in that: The natural antibacterial substance combination includes the following components by mass fraction: vitamin C 10.42%-23.26%, balsamic vinegar powder 6.25%-10.71%, green tangerine powder 69.77%-83.33%.

2. A natural antibacterial substance combination according to claim 1, characterized in that: The natural antibacterial substance combination includes the following components by mass fraction: 18.18% vitamin C, 9.09% balsamic vinegar powder, and 72.73% green tangerine powder.

3. A natural antibacterial substance combination according to claim 1, characterized in that: The natural antibacterial substance combination includes the following components by mass fraction: 23.26% vitamin C, 6.98% balsamic vinegar powder, and 69.77% green tangerine powder.

4. A natural antibacterial substance combination according to claim 1, characterized in that: The natural antibacterial substance combination includes the following components by mass fraction: vitamin C 17.86%, balsamic vinegar powder 10.71%, green tangerine powder 71.43%.

5. A natural antibacterial substance combination according to claim 1, characterized in that: The natural antibacterial substance combination includes the following components by mass fraction: vitamin C 10.42%, balsamic vinegar powder 6.25%, green tangerine powder 83.33%.

6. A natural antibacterial substance combination according to any one of claims 1 to 5, characterized in that: The natural antibacterial substance combination also includes cinnamon essential oil.

7. Use of a natural antibacterial substance combination as described in any one of claims 1 to 6 in preserving prefabricated steamed bread at room temperature.

8. The use according to claim 7, characterized in that: The method for using the natural antibacterial substance combination is as follows: add 1 g of yeast and 2.475-4.320 g of the natural antibacterial substance combination to every 100 g of flour, add 50 mL of water, knead the dough, and let it rise for 30 min at a temperature of 37° C. and a relative humidity of 85%, divide the dough into groups and re-knead them into shapes, let them rise again in a proofing box for 15 min, steam them in a steamer for 30 min, then cool them, and seal the steamed buns with sterile sealed bags.

9. The use according to claim 8, characterized in that: The application can significantly extend the shelf life of steamed bread stored at room temperature.

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