Preparation method and application of macadamia nut green peel antibacterial agent

Abstract

The application discloses a preparation method and application of an antibacterial agent of macadamia nut green peel and belongs to the technical field of antibacterial agent preparation. The preparation steps are as follows: after the macadamia nut green peel is cleaned and dried, the macadamia nut green peel is crushed to obtain macadamia nut green peel powder; distilled water is added to the macadamia nut green peel powder, and heating is stopped after most of the distilled water is evaporated, so that a concentrated suspension is obtained; and finally, the concentrated suspension is dried to obtain the antibacterial agent. The antibacterial agent prepared by the method has good antibacterial effect on staphylococcus aureus, and the prepared antibacterial agent is a solid and is easy to store.

Description

Technical Field

[0001] A method for preparing and applying an antibacterial agent for macadamia nut husks belongs to the technical field of antibacterial agent preparation methods and applications. Background Technology

[0002] Macadamia integrifolia, also known as Hawaiian nut, consists mainly of three parts: the green husk, the shell, and the kernel. The green husk accounts for 45% to 60% of the fresh nut's weight. Therefore, a large amount of green husk byproducts are generated during post-harvest processing and initial processing. However, since the green husk cannot be eaten directly, most of it is discarded, with only a small portion used for fertilizer production. The large-scale discarding of green husks results in a serious waste of resources. Therefore, conducting research on the comprehensive utilization of macadamia nut green husks is of great practical significance for saving resources and improving industrial efficiency.

[0003] Current research has found that macadamia nut husks are rich in taurine, therefore they can be used to prepare various cosmetics, such as shower gels, skin creams, and toners. However, current research does not mention that macadamia nut husks can be used to prepare antibacterial agents. Summary of the Invention

[0004] To make more effective use of macadamia nut husks, one objective of this invention is to provide a method for preparing an antibacterial agent for macadamia nut husks, comprising:

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

[0006] (2) Mix macadamia nut green skin powder with distilled water to obtain a suspension. Boil the suspension and then heat it at a constant temperature to obtain a concentrated suspension.

[0007] (3) Dry the concentrated suspension obtained in step (2) and collect the solid obtained. The solid obtained is the antibacterial agent.

[0008] Preferably, in step (2), the solid-liquid ratio of macadamia nut green skin powder to distilled water is 1:(40-90), with the unit being 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 will be 5 mL to 12.5 mL).

[0010] The second objective of this invention is to provide an antibacterial agent for macadamia nut husks in the inhibition of Staphylococcus aureus.

[0011] Beneficial effects of the present invention

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

[0013] (2) The antibacterial agent for macadamia nut peel prepared by the present invention has excellent antibacterial effect, with a maximum antibacterial rate of 93% against Staphylococcus aureus. Attached Figure Description

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

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

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

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

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

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

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

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

[0022] Figure 9 The antibacterial effect of processed macadamia nut husk powder on Staphylococcus aureus. Detailed Implementation

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following embodiments are merely 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 is determined by the claims.

[0024] Example 1

[0025] The preparation of an antibacterial agent for macadamia nut husks includes the following steps:

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

[0027] (2) Take 1.0g of macadamia nut green skin powder into a small beaker containing 50mL of distilled water to obtain a suspension.

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

[0029] (4) The dried solid obtained by drying the concentrated suspension in an oven is the antibacterial agent.

[0030] Example 2

[0031] The preparation of an antibacterial agent for macadamia nut husks includes the following steps:

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

[0033] (2) Take 1.0g of macadamia nut green skin powder into a small beaker containing 90mL of distilled water to obtain a suspension.

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

[0035] (4) The dried solid obtained by drying the concentrated suspension in an oven is the antibacterial agent.

[0036] Example 3

[0037] The preparation of an antibacterial agent for macadamia nut husks includes the following steps:

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

[0039] (2) Take 1.0g of macadamia nut green skin powder into a small beaker containing 40mL of distilled water to obtain a suspension.

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

[0041] (4) The dried solid obtained by drying the concentrated suspension in an oven is the antibacterial agent.

[0042] Comparative Example 1

[0043] The preparation of an antibacterial agent for macadamia nut husks includes the following steps:

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

[0045] (2) Take 1.0g of macadamia nut green skin powder into a small beaker containing 50mL of distilled water to obtain a suspension.

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

[0047] (4) The obtained macadamia nut green skin paste is placed in an oven and dried. The resulting dry solid is the antibacterial agent.

[0048] Comparative Example 2

[0049] The preparation of an antibacterial agent for macadamia nut husks includes the following steps:

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

[0051] (2) Take 1.0g of macadamia nut green skin powder into a small beaker containing 50mL of distilled water to obtain a suspension.

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

[0053] (4) The dried solid obtained by drying the concentrated suspension in an oven is the antibacterial agent.

[0054] Comparative Example 3

[0055] The preparation of an antibacterial agent for macadamia nut husks includes the following steps:

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

[0057] (2) Take 1.0g of macadamia nut green skin powder into a small beaker containing 30mL of distilled water to obtain a suspension.

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

[0059] (4) The dried solid obtained by drying the concentrated suspension in an oven is the antibacterial agent.

[0060] Comparative Example 4

[0061] The preparation of an antibacterial agent for macadamia nut husks includes the following steps:

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

[0063] (2) Take 1.0g of macadamia nut green skin powder into a small beaker containing 50mL of distilled water to obtain a suspension.

[0064] (3) Place the small beaker containing the suspension on a heating plate and boil it at 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 filter residue and filtrate. The obtained filtrate and filter residue are antibacterial agents.

[0066] Comparative Example 5

[0067] A method for preparing an antibacterial agent using macadamia nut husks includes the following steps:

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

[0069] (2) Take 1.0g of macadamia nut green skin coarse powder into a small beaker containing 20mL of distilled water to obtain a suspension. Sonicate the suspension at room temperature for 20min, then perform hydrothermal reaction at 220℃ for 12 hours. Cool naturally to room temperature, filter to obtain filter residue and filtrate. The obtained filtrate and filter residue are antibacterial agents.

[0070] Experimental Example 1

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

[0072] The Gram-positive bacterium Staphylococcus aureus (CCTCC AB 91093) was selected as the experimental strain for antibacterial testing.

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

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

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

[0076] The specific experimental steps are as follows:

[0077] (1) The experimental strain was added to sterile LB liquid medium and cultured to a concentration of 5×10⁻⁶. 6 A bacterial suspension with CFU / mL, when the concentration of the cell suspension is greater than 5 × 10⁻⁶. 6 When the concentration is CFU / mL, it is diluted with sterile water to obtain a diluted bacterial solution.

[0078] (2) Mix 5 mg of the test sample (antibacterial agent, filter residue and filtrate prepared in all examples and comparative examples) with 10 mL of diluted bacterial solution in a sterile test tube to prepare a suspension. Incubate the suspension on a shaker at 37°C and 200 rpm for 30 min. Take 100 μL and drop it into a culture dish containing LB agar medium. Spread the bacterial solution evenly on the medium using the plate spreading method. Place the culture dish in a constant temperature incubator and incubate for 18–24 h.

[0079] (3) After incubation, 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 test samples in Example 1 and Comparative Examples 1-5 against Staphylococcus aureus were as follows: Figures 1 to 8 As shown in the figures (A in all figures represents the blank control, and B represents the experimental group), it can be clearly seen from the figures that the antibacterial agent prepared in Example 1 has a significantly better antibacterial effect against Staphylococcus aureus than the antibacterial agent prepared in the comparative example.

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

[0083] Table 1. Antibacterial rates of the tested samples from the examples and comparative examples.

[0084] Example Staphylococcus aureus antibacterial rate Example 1 93％ Comparative Example 1 0％ Comparative Example 2 31％ Comparative Example 3 34％ Comparative Example 4 (filtrate) 53％ Comparative Example 4 (Filter Ash) 47％ Comparative Example 5 (filtrate) 29％ Comparative Example 5 (Filter Ash) 18％

[0085] Table 1 provides a clearer view of the antibacterial agent prepared by the method described in this invention, which exhibits the best antibacterial effect against Staphylococcus aureus.

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

[0087] Finally, the antibacterial effect of macadamia nut husk powder was tested using the same method, and the results were as follows: Figure 9 As shown, from Figure 9 It can be seen that the antibacterial effect of macadamia nut husk is not obvious. Calculations show that the antibacterial rate of untreated macadamia nut husk powder against Staphylococcus aureus is 0%.

Claims

1. A method for preparing an antibacterial agent for macadamia nut husks, characterized in that: Includes the following steps: (1) Wash the green husks of macadamia nuts, dry them in an oven, and then grind them in a grinder to obtain macadamia nut green husk powder. (2) Take 1.0g of macadamia nut green skin powder into a small beaker containing 50mL of distilled water to obtain a suspension; (3) Place the small beaker containing the suspension on a heating plate and boil it at a constant temperature of 85°C until the volume of the suspension is 10 mL to obtain a concentrated suspension. (4) The dried solid obtained by drying the concentrated suspension in an oven is the antibacterial agent.

2. The application of the antibacterial agent prepared by the method of claim 1 in inhibiting Staphylococcus aureus.

Images