Preparation method and application of macadamia nut green peel antibacterial agent

Abstract

The invention discloses a preparation method and application of a macadamia nut green peel antibacterial agent, and belongs to the technical field of antibacterial agent preparation. The preparation method comprises the following steps: cleaning and drying the macadamia nut green peel, crushing to obtain macadamia nut green peel powder, adding distilled water into the macadamia nut green peel powder, heating until most of the distilled water is evaporated, stopping heating to obtain a concentrated suspension, and finally drying the concentrated suspension to obtain the antibacterial agent. The antibacterial agent prepared by the method disclosed by the invention has a good antibacterial effect on staphylococcus aureus, and the prepared antibacterial agent is solid and is easy to store.

Description

Technical Field

[0001] The invention discloses a preparation method and application of a macadamia nut green peel antibacterial agent, belonging to the technical field of preparation methods and application of antibacterial agents. Background Art

[0002] Macadamia nut (Macadamiaintegrifolia), also known as macadamia nut, is mainly composed of three parts: green peel, shell and kernel. The green peel accounts for 45% to 60% of the fresh fruit weight. Therefore, a large amount of green peel by-products are produced during post-harvest and primary processing. However, because the green peel cannot be eaten directly, most of it is discarded, and only a small part of the green peel is used to prepare fertilizer. The large-scale discard of green peel causes a serious waste of resources. Therefore, research on the comprehensive utilization of macadamia nut green peel is of great practical significance for saving resources and improving industrial efficiency.

[0003] Current research has found that macadamia nut green peel is rich in tofu glycosides, so macadamia nut green peel can be used to prepare various cosmetics, such as shower gel, skin cream, lotion, etc. However, current research does not mention that macadamia nut green peel can be prepared into an antibacterial agent. Summary of the invention

[0004] In order to make more effective use of macadamia nut green peel, one of the objects of the present invention is to provide a method for preparing a macadamia nut green peel antibacterial agent, comprising:

[0005] (1) Wash the green peel of macadamia nuts, dry it, and then crush it to obtain the green peel powder of macadamia nuts.

[0006] (2) Mixing macadamia nut green peel powder with distilled water to obtain a suspension, boiling the suspension, and then heating at a constant temperature to obtain a concentrated suspension.

[0007] (3) Drying the concentrated suspension obtained in step (2) and collecting the obtained solid, which is the antibacterial agent.

[0008] Preferably, in step (2), the solid-to-liquid ratio of the macadamia nut green peel powder to distilled water is 1:(40-90), expressed in g / mL.

[0009] Preferably, the volume of the concentrated suspension obtained in step (2) is 10% to 25% of the volume of distilled water (for example, if 50 mL of distilled water is used, the final volume of the concentrated suspension is 5 mL to 12.5 mL).

[0010] The second purpose of the present invention is to provide an application of a macadamia nut green peel antibacterial agent in inhibiting Staphylococcus aureus.

[0011] Beneficial Effects of the Invention

[0012] (1) The method of the present invention is simple and easy to operate, has no special requirements for equipment, does not require the use of organic solvents, and is safer in the preparation process. In addition, the prepared macadamia nut green peel antibacterial agent is solid and easy to store.

[0013] (2) The macadamia nut green peel antibacterial agent prepared by the present invention has excellent antibacterial effect, and the maximum antibacterial rate against Staphylococcus aureus reaches 93%. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The antibacterial effect of the antibacterial agent prepared in Example 1 on Staphylococcus aureus.

[0015] Figure 2 The antibacterial effect of the antibacterial agent prepared in Comparative Example 1 on Staphylococcus aureus.

[0016] Figure 3 The antibacterial effect of the antibacterial agent prepared in Comparative Example 2 on Staphylococcus aureus.

[0017] Figure 4 The antibacterial effect of the antibacterial agent prepared in Comparative Example 3 on Staphylococcus aureus.

[0018] Figure 5 The antibacterial effect of the antibacterial agent (filtrate) prepared in Comparative Example 4 on Staphylococcus aureus.

[0019] Figure 6 The antibacterial effect of the antibacterial agent (filter residue) prepared in Comparative Example 4 on Staphylococcus aureus.

[0020] Figure 7 The antibacterial effect of the antibacterial agent (filtrate) prepared in Comparative Example 5 on Staphylococcus aureus.

[0021] Figure 8 The antibacterial effect of the antibacterial agent (filter residue) prepared in Comparative Example 5 on Staphylococcus aureus.

[0022] Fig. 9 The antibacterial effect of processed macadamia nut green peel powder on Staphylococcus aureus. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0024] Example 1

[0025] A preparation method of a macadamia nut green peel antibacterial agent comprises the following steps:

[0026] (1) Wash the green peel of macadamia nuts, dry it in an oven, and then grind it in a grinder to obtain green peel powder of macadamia nuts.

[0027] (2) Take 1.0 g of macadamia nut green peel powder and place it in a small beaker containing 50 mL of distilled water to obtain a suspension.

[0028] (3) Place the small beaker containing the suspension on a heating plate and heat to a constant temperature of 85°C until the volume of the suspension is 10 mL to obtain a concentrated suspension.

[0029] (4) The concentrated suspension is dried in an oven to obtain a dry solid, which is the antibacterial agent.

[0030] Example 2

[0031] A preparation method of a macadamia nut green peel antibacterial agent comprises the following steps:

[0032] (1) Wash the green peel of macadamia nuts, dry it in an oven, and then grind it in a grinder to obtain green peel powder of macadamia nuts.

[0033] (2) Take 1.0 g of macadamia nut green peel powder and place it in a small beaker filled with 90 mL of distilled water to obtain a suspension.

[0034] (3) Place the small beaker containing the suspension on a heating plate and heat to a constant temperature of 85°C until the volume of the suspension is 10 mL to obtain a concentrated suspension.

[0035] (4) The concentrated suspension is dried in an oven to obtain a dry solid, which is the antibacterial agent.

[0036] Example 3

[0037] A preparation method of a macadamia nut green peel antibacterial agent comprises the following steps:

[0038] (1) Wash the green peel of macadamia nuts, dry it in an oven, and then grind it in a grinder to obtain green peel powder of macadamia nuts.

[0039] (2) Take 1.0 g of macadamia nut green peel powder and place it in a small beaker containing 40 mL of distilled water to obtain a suspension.

[0040] (3) Place the small beaker containing the suspension on a heating plate and heat to a constant temperature of 85°C until the volume of the suspension is 10 mL to obtain a concentrated suspension.

[0041] (4) The concentrated suspension is dried in an oven to obtain a dry solid, which is the antibacterial agent.

[0042] Comparative Example 1

[0043] A preparation method of a macadamia nut green peel antibacterial agent comprises the following steps:

[0044] (1) Wash the green peel of macadamia nuts, dry it in an oven, and then grind it in a grinder to obtain green peel powder of macadamia nuts.

[0045] (2) Take 1.0 g of macadamia nut green peel powder and place it in a small beaker containing 50 mL of distilled water to obtain a suspension.

[0046] (3) Place a small beaker containing the suspension on a heating plate and boil it at a constant temperature of 85°C until no distilled water remains, thereby obtaining a macadamia nut green skin paste.

[0047] (4) The obtained macadamia nut green peel paste is placed in an oven and dried to obtain a dry solid, which is the antibacterial agent.

[0048] Comparative Example 2

[0049] A preparation method of a macadamia nut green peel antibacterial agent comprises the following steps:

[0050] (1) Wash the green peel of macadamia nuts, dry it in an oven, and then grind it in a grinder to obtain green peel powder of macadamia nuts.

[0051] (2) Take 1.0 g of macadamia nut green peel powder and place it in a small beaker containing 50 mL of distilled water to obtain a suspension.

[0052] (3) Place the small beaker containing the suspension on a heating plate and heat to a constant temperature of 85°C until the volume of the suspension is 5 mL to obtain a concentrated suspension.

[0053] (4) The concentrated suspension is dried in an oven to obtain a dry solid, which is the antibacterial agent.

[0054] Comparative Example 3

[0055] A preparation method of a macadamia nut green peel antibacterial agent comprises the following steps:

[0056] (1) Wash the green peel of macadamia nuts, dry it in an oven, and then grind it in a grinder to obtain green peel powder of macadamia nuts.

[0057] (2) Take 1.0 g of macadamia nut green peel powder and place it in a small beaker containing 30 mL of distilled water to obtain a suspension.

[0058] (3) Place the small beaker containing the suspension on a heating plate and heat to a constant temperature of 85°C until the volume of the suspension is 10 mL to obtain a concentrated suspension.

[0059] (4) The concentrated suspension is dried in an oven to obtain a dry solid, which is the antibacterial agent.

[0060] Comparative Example 4

[0061] A preparation method of a macadamia nut green peel antibacterial agent comprises the following steps:

[0062] (1) Wash the green peel of macadamia nuts, dry it in an oven, and then grind it in a grinder to obtain green peel powder of macadamia nuts.

[0063] (2) Take 1.0 g of macadamia nut green peel powder and place it in a small beaker containing 50 mL of distilled water to obtain a suspension.

[0064] (3) Place the small beaker containing the suspension on a heating plate and heat to a constant temperature of 85°C until the volume of the suspension is 10 mL to obtain a concentrated suspension.

[0065] (4) The concentrated suspension is filtered to obtain a filter residue and a filtrate, and the obtained filtrate and filter residue are the antibacterial agent.

[0066] Comparative Example 5

[0067] A method for preparing an antibacterial agent using macadamia nut green peel comprises the following steps:

[0068] (1) Wash the green peel of macadamia nuts, dry it in an oven, and then grind it in a grinder to obtain green peel powder of macadamia nuts.

[0069] (2) 1.0 g of macadamia nut green peel coarse powder was placed in a small beaker containing 20 mL of distilled water to obtain a suspension. The suspension was subjected to ultrasonic treatment at room temperature for 20 min, followed by hydrothermal reaction at 220° C. for 12 h. The suspension was naturally cooled to room temperature, and filtered to obtain a residue and a filtrate. The obtained filtrate and residue were the antibacterial agent.

[0070] Test Example 1

[0071] The antibacterial agents prepared in Example 1 and Comparative Examples 1 to 5 were used to conduct antibacterial tests, and all the antibacterial agents to be tested were referred to as test samples.

[0072] The Gram-positive bacteria Staphylococcus aureus (S. aureus, CCTCC AB 91093) was selected as the experimental strain for antibacterial detection.

[0073] The preparation method of the culture medium used in the experiment is as follows:

[0074] LB agar medium: 5 g tryptone, 2.5 g yeast powder, 5 g sodium chloride, 500 mL distilled water, 7.5 g agar;

[0075] LB liquid culture medium: 5 g tryptone, 2.5 g yeast powder, 5 g sodium chloride, and 500 mL distilled water.

[0076] The specific test steps are as follows:

[0077] (1) Add the experimental strain into sterile LB liquid culture medium and culture it to a concentration of 5×10 6 CFU / mL of bacterial suspension, when the concentration of cell suspension is greater than 5×10 6 CFU / mL, dilute with sterile water to obtain diluted bacterial solution.

[0078] (2) 5 mg of the sample to be tested (the antibacterial agent, filter residue and filtrate prepared in all embodiments and comparative examples) was mixed with 10 mL of the diluted bacterial solution and placed in a sterile test tube to prepare a suspension, which was incubated on a shaker at 37°C and 200 rpm for 30 min. 100 μL of the suspension was dripped into a culture dish with LB agar medium, and the bacterial solution was evenly spread on the culture medium by the spread plate method. The culture dish was placed in a constant temperature incubator and cultured for 18 to 24 h.

[0079] (3) After cultivation, the antibacterial rate of each sample was calculated using the colony counting method.

[0080] The calculation formula is as follows:

[0081] After testing, the antibacterial effects of the samples of Example 1 and Comparative Examples 1 to 5 on Staphylococcus aureus are as follows: Figures 1 to 8 As shown (in all figures, A is the blank control and B is the experimental group), it can be intuitively seen from the figure that the antibacterial effect of the antibacterial agent prepared in Example 1 on Staphylococcus aureus is significantly better than that of the antibacterial agent prepared in the comparative example.

[0082] The antibacterial rates of the antibacterial agents prepared in Example 1 and Comparative Examples 1 to 5 are calculated and are shown in Table 1.

[0083] Table 1 Antibacterial rate of samples tested in embodiments and comparative examples

[0084] Example Antibacterial rate of Staphylococcus aureus Example 1 93％ Comparative Example 1 0％ Comparative Example 2 31％ Comparative Example 3 34％ Comparative Example 4 (filtrate) 53％ Comparative Example 4 (filter residue) 47％ Comparative Example 5 (filtrate) 29％ Comparative Example 5 (filter residue) 18％

[0085] It can be more intuitively seen from Table 1 that the antibacterial agent prepared by the method of the present invention has the best antibacterial effect on Staphylococcus aureus.

[0086] The antibacterial effects of the antibacterial agents prepared in Examples 2 and 3 are similar to those in Example 1.

[0087] Finally, the same method was used to test the antibacterial effect of macadamia nut green peel powder. The results are as follows Fig. 9 As shown, from Fig. 9 It can be seen that the antibacterial effect of macadamia nut green peel is not obvious. After calculation, the antibacterial rate of untreated macadamia nut green peel powder against Staphylococcus aureus is 0%.

Claims

1. A method for preparing a macadamia nut green peel antibacterial agent, characterized in that: The following steps are involved: (1) washing the green peel of macadamia nuts, drying it and then crushing it to obtain the green peel powder of macadamia nuts; (2) mixing macadamia nut green peel powder with distilled water to obtain a suspension, boiling the suspension, and then heating at a constant temperature to obtain a concentrated suspension; (3) Drying the concentrated suspension obtained in step (2) and collecting the obtained solid, which is the antibacterial agent.

2. The method for preparing the macadamia nut green peel antibacterial agent according to claim 1, characterized in that: In step (2), the solid-to-liquid ratio of the macadamia nut green peel powder to distilled water is 1:(40-90), in units of g:mL.

3. The method for preparing the macadamia nut green peel antibacterial agent according to claim 1, characterized in that: The volume of the concentrated suspension obtained in step (2) is 10% to 25% of the volume of distilled water.

4. Use of the antibacterial agent prepared by the method of claim 1 in inhibiting Staphylococcus aureus.

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