A method for extracting macadamia nut oil bodies

Abstract

The invention discloses a method for extracting macadamia nut oil bodies, comprising the following steps: (1) mixing macadamia nut kernels with a solvent and then grinding them, and filtering to obtain a macadamia nut kernel crude emulsion; (2) adding sucrose to the macadamia nut kernel crude emulsion obtained in step (1) to dissolve the mixture to obtain a first emulsion, adjusting the pH of the first emulsion to 6-8 and then centrifuging, and collecting a floating substance; (3) dispersing the floating substance obtained in step (2) in a solvent to obtain a dispersion liquid, then adding sucrose to the dispersion liquid to dissolve the mixture to obtain a second emulsion, adjusting the pH of the second emulsion to 6-8 and then centrifuging, and collecting a floating milky substance, wherein the floating milky substance is the macadamia nut kernel oil body. The macadamia nut oil body extracted by the extraction method ensures that the extracted oil body structure remains stable while also having a high extraction yield and purity.

Description

Technical Field

[0001] The invention belongs to the technical field of nut oil body preparation, and particularly relates to a method for extracting macadamia nut oil bodies. Background Art

[0002] Macadamia nuts, also known as macadamia nuts, Australian walnuts, Queensland chestnuts, and Queensland nuts, are a tree nut native to southeastern Queensland, Australia. They belong to the Proteaceae family and are known as the "Queen of Dried Fruits" for their nutritious properties and unique taste. Macadamia nuts are extremely rich in oil, primarily unsaturated fatty acids, particularly monounsaturated fatty acids. Monounsaturated fatty acids account for over 96% of the unsaturated fatty acids in macadamia nuts, of which oleic acid accounts for approximately 64% and palmitoleic acid for approximately 15%.

[0003] Oil bodies are the smallest storage structures for oils in plant seed cells, also known as liposomes or oleosomes in research. Plant oil bodies are primarily composed of neutral oils (triglycerides), phospholipids, and endogenous proteins. They possess unique structural characteristics, with a nearly spherical shape, a central substance composed of triglycerides, and a dense protective membrane on the outer surface that blocks contact between lipase and oil, allowing the oil to remain stable during storage. This protective membrane, primarily composed of phospholipids and endogenous proteins, forms a natural microcapsule. The endogenous proteins on the outer membrane of the oil body primarily include oleosin, caleosin, and steroleosin. These three proteins play an important role in maintaining internal homeostasis within the oil body and also play a major role in the growth and germination of plant seeds.

[0004] Currently, macadamia nut processing is mainly at the primary stage, with relatively slow development in the field of deep processing, and the potential added value of macadamia nuts has not been fully explored and enhanced. As a stable form of oil in plant seeds, oil bodies naturally have good antioxidant properties due to their special structure. At the same time, oil bodies also have emulsification and gel properties. During processing, oil bodies do not require the use of emulsifiers or multiple homogenizations to form emulsions, and can be transformed into emulsion gels at a certain concentration. Therefore, the research and development of macadamia nut oil bodies has become a new direction for future development. It is urgent to develop a method for extracting macadamia nut oil bodies that ensures the extracted oil bodies remain stable (without destroying the stable surface structure) while taking into account the extraction yield and purity of the oil bodies (removing other components such as exogenous proteins). Summary of the Invention

[0005] The present invention aims to address at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for extracting macadamia nut oil bodies. The method achieves a stable structure of the extracted macadamia nut oil bodies while maintaining a high extraction yield and purity.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] A method for extracting macadamia nut oil bodies comprises the following steps: (1) mixing macadamia nut kernels with a solvent, grinding the mixture, and filtering to obtain a macadamia nut kernel crude emulsion; (2) adding sucrose to the macadamia nut kernel crude emulsion obtained in step (1) to dissolve the mixture to obtain a first emulsion, adjusting the pH of the first emulsion to 6-8, centrifuging the mixture, and collecting a floating substance; and (3) dispersing the floating substance obtained in step (2) in a solvent to obtain a dispersion, then adding sucrose to the dispersion to obtain a second emulsion, adjusting the pH of the second emulsion to 6-8, centrifuging the mixture, and collecting a floating milky substance, wherein the floating milky substance is the macadamia nut kernel oil body.

[0008] Preferably, in step (1), the solvent is water, the macadamia nut kernels and water are mixed in a mass ratio of 1: (2-5) and then stirred and ground once, and a filter residue and a primary filtrate are obtained after filtration. The filter residue is added with water of the same mass as the primary stirring and grinding, and then stirred, ground and filtered. The filter residue is treated 2-5 times, and the filtrate obtained during the filter residue treatment is mixed with the primary filtrate to obtain the macadamia nut kernel crude emulsion.

[0009] Further preferably, in step (1), the solvent is water, the macadamia nut kernels and water are mixed in a mass ratio of 1: (2-3) and then stirred and ground once, and a filter residue and a primary filtrate are obtained after filtration. The same mass of water as the primary stirring and grinding is added to the filter residue, and then stirred, ground and filtered. The filter residue is treated 2-3 times, and the filtrate obtained during the filter residue treatment is mixed with the primary filtrate to obtain the macadamia nut kernel crude emulsion.

[0010] Preferably, the stirring and grinding is performed at a speed of 18,000-32,000 rpm, and the stirring and grinding time is 1-5 min.

[0011] Further preferably, the number of revolutions of the stirring and grinding is 20,000-30,000 rpm, and the time of the stirring and grinding is 2-3 min.

[0012] Preferably, in step (2), the mass ratio of the added sucrose to the macadamia kernel crude emulsion is (0.1-0.3):1.

[0013] Further preferably, in step (2), the mass ratio of the added sucrose to the macadamia kernel crude emulsion is (0.15-0.25):1.

[0014] Further preferably, in step (2), the pH of the first emulsion is adjusted to 6.8-8 and then centrifuged.

[0015] Preferably, in step (2), the centrifugal temperature is 0-4°C, the centrifugal speed is 8000-12000 rpm, and the centrifugal time is 25-40 min.

[0016] Further preferably, in step (2), the centrifugal temperature is 3-4°C, the centrifugal speed is 9000-11000 rpm, and the centrifugal time is 30-40 min.

[0017] Preferably, in step (3), the solvent is water, and the floating matter is mixed with water in a mass ratio of 1:(5-8) and then stirred and dispersed to obtain the dispersion.

[0018] Preferably, in step (3), the mass ratio of the added sucrose to the dispersion is (0.1-0.3):1.

[0019] Further preferably, in step (3), the mass ratio of the added sucrose to the dispersion is (0.15-0.25):1.

[0020] Further preferably, in step (3), the pH of the second emulsion is adjusted to 6.8-8 and then centrifuged.

[0021] Preferably, in step (3), the centrifugal temperature is 0-4°C, the centrifugal speed is 8000-12000 rpm, and the centrifugal time is 25-40 min.

[0022] Further preferably, in step (3), the centrifugal temperature is 3-4°C, the centrifugal speed is 9000-11000 rpm, and the centrifugal time is 30-40 min.

[0023] Preferably, in step (2) and step (3), the pH is adjusted using 0.05-0.2 mol / L HCl solution and 0.5-2 mol / L NaOH solution.

[0024] The beneficial effects of the present invention are:

[0025] The method for extracting macadamia nut oil bodies of the present invention does not require the use of additives and has simple steps and easy-to-meet extraction conditions. By adjusting the pH of the emulsion to 6-8 during the extraction process and then performing centrifugation, a high extraction rate and purity of the macadamia nut oil bodies can be ensured without destroying the structure of the macadamia nut oil bodies, which is beneficial to the subsequent application of the macadamia nut oil bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a real picture of the macadamia kernel oil body prepared in Example 3 of the present invention;

[0027] Figure 2 The extraction rate and protein content of macadamia kernel oil bodies under different pH conditions;

[0028] Figure 3 The electrophoretic diagrams are obtained by reducing the protein components in the oil bodies of macadamia kernels using SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) under different pH conditions;

[0029] Figure 4 The extraction rate and protein content of macadamia kernel oil bodies under different sucrose contents;

[0030] Figure 5 The electrophoretic diagrams are obtained by reducing the protein components in the oil bodies of macadamia kernels using SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) at different sucrose contents. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to specific embodiments.

[0032] Example 1:

[0033] A method for extracting macadamia nut oil bodies comprises the following steps:

[0034] (1) Take 120g of macadamia kernels, weigh 960g of distilled water, and then divide the distilled water into four equal parts (240g / part). Add the first part of distilled water and 120g of macadamia kernels into a blender and grind at 18000rpm for 5min. The ground slurry is filtered through four layers of gauze. The filter residue is mixed with the second part of distilled water, stirred again in the blender at the same speed for 5min and filtered to obtain the filter residue. Repeat the above operation for 2 more times. The four filter slurries obtained are mixed together to obtain the macadamia kernel crude emulsion.

[0035] (2) 500 g of macadamia nut kernel crude emulsion was added with 50 g of sucrose and stirred until completely dissolved to obtain a first emulsion. The pH value of the first emulsion was adjusted to 6 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The pH-adjusted first emulsion was transferred to a centrifuge tube and centrifuged at 8000 rpm for 50 min at 4°C to collect the floating milky substance.

[0036] (3) The collected supernatant was dispersed in distilled water at a mass ratio of 1:5, and the mixture was stirred to obtain a dispersion. Sucrose (10% by mass of the dispersion) was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH value of the second emulsion was adjusted to 6 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The mixture was centrifuged at 8000 rpm for 40 min at 4°C. The resulting floating emulsion was the macadamia kernel oil body.

[0037] Example 2:

[0038] A method for extracting macadamia nut oil bodies comprises the following steps:

[0039] (1) Take 120g of macadamia kernels, weigh 2400g of distilled water, and then divide the distilled water into four equal parts (600g / part). Add the first part of distilled water and 120g of macadamia kernels into a blender and grind at 32000rpm for 1min. The ground slurry is filtered through four layers of gauze. The filter residue is mixed with the second part of distilled water, stirred again at the same speed in the blender for 1min and filtered to obtain the filter residue. Repeat the above operation for the filter residue twice more. The four filter slurries obtained are mixed together to obtain the macadamia kernel crude emulsion.

[0040] (2) 500 g of macadamia nut kernel crude emulsion was added with 150 g of sucrose and stirred until completely dissolved to obtain a first emulsion. The pH value of the first emulsion was adjusted to 8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The pH-adjusted first emulsion was transferred to a centrifuge tube and centrifuged at 12,000 rpm for 30 min at 4°C to collect the floating milky substance.

[0041] (3) The collected supernatant was dispersed in distilled water at a mass ratio of 1:8, and the mixture was stirred to obtain a dispersion. Sucrose (30% by mass of the dispersion) was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH value of the second emulsion was adjusted to 8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The mixture was centrifuged at 12,000 rpm for 30 min at 4°C. The resulting floating emulsion was the macadamia kernel oil body.

[0042] Example 3:

[0043] A method for extracting macadamia nut oil bodies comprises the following steps:

[0044] (1) Take 120g of macadamia kernels, weigh 1200g of distilled water, and then divide the distilled water into four equal parts (300g / part). Add the first part of distilled water and 120g of macadamia kernels into a blender and grind at 25000rpm for 2min. The ground slurry is filtered through four layers of gauze. The filter residue is mixed with the second part of distilled water, stirred again at the same speed in the blender for 2min and filtered to obtain the filter residue. Repeat the above operation for the filter residue twice more. The four filter slurries obtained are mixed together to obtain the macadamia kernel crude emulsion.

[0045] (2) 500 g of macadamia nut kernel crude emulsion was added with 100 g of sucrose and stirred until completely dissolved to obtain a first emulsion. The pH value of the first emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The pH-adjusted first emulsion was transferred to a centrifuge tube and centrifuged at 10,000 rpm for 30 min at 4°C to collect the floating milky substance.

[0046] (3) The collected supernatant was dispersed in distilled water at a mass ratio of 1:6, and the mixture was stirred to obtain a dispersion. Sucrose (20% by mass of the dispersion) was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH value of the second emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The mixture was centrifuged at 10,000 rpm for 30 min at 4°C. The resulting floating milky substance was the macadamia kernel oil body. The actual picture of the macadamia kernel oil body is shown in the figure below. Figure 1 As shown by Figure 1 It can be seen that a solid paste with a milky white appearance was prepared.

[0047] Example 4 (the only difference from Example 3 is that the pH is adjusted to 8 in both steps (2) and (3)):

[0048] A method for extracting macadamia nut oil bodies comprises the following steps:

[0049] (1) Take 120g of macadamia kernels, weigh 1200g of distilled water, and then divide the distilled water into four equal parts (300g / part). Add the first part of distilled water and 120g of macadamia kernels into a blender and grind at 25000rpm for 2min. The ground slurry is filtered through four layers of gauze. The filter residue is mixed with the second part of distilled water, stirred again at the same speed in the blender for 2min and filtered to obtain the filter residue. Repeat the above operation for the filter residue twice more. The four filter slurries obtained are mixed together to obtain the macadamia kernel crude emulsion.

[0050] (2) 500 g of macadamia nut kernel crude emulsion was added with 100 g of sucrose and stirred until completely dissolved to obtain a first emulsion. The pH value of the first emulsion was adjusted to 8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The pH-adjusted first emulsion was transferred to a centrifuge tube and centrifuged at 10,000 rpm for 30 min at 4°C to collect the floating milky substance.

[0051] (3) The collected supernatant was dispersed in distilled water at a mass ratio of 1:6, and the mixture was stirred to obtain a dispersion. Sucrose (20% by mass of the dispersion) was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH value of the second emulsion was adjusted to 8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The mixture was centrifuged at 10,000 rpm for 30 min at 4°C. The resulting floating emulsion was the macadamia kernel oil body.

[0052] Example 5:

[0053] A method for extracting macadamia nut oil bodies comprises the following steps:

[0054] (1) Take 120g of macadamia kernels, weigh 1200g of distilled water, and then divide the distilled water into four equal parts (300g / part). Add the first part of distilled water and 120g of macadamia kernels into a blender and grind at 25000rpm for 2min. The ground slurry is filtered through four layers of gauze. The filter residue is mixed with the second part of distilled water, stirred again at the same speed in the blender for 2min and filtered to obtain the filter residue. Repeat the above operation for the filter residue twice more. The four filter slurries obtained are mixed together to obtain the macadamia kernel crude emulsion.

[0055] (2) 500 g of macadamia nut kernel crude emulsion was added with 50 g of sucrose and stirred until completely dissolved to obtain a first emulsion. The pH value of the first emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The pH-adjusted first emulsion was transferred to a centrifuge tube and centrifuged at 10,000 rpm for 30 min at 4°C to collect the floating milky substance.

[0056] (3) The collected supernatant was dispersed in distilled water at a mass ratio of 1:6, and the mixture was stirred to obtain a dispersion. Sucrose (10% by mass of the dispersion) was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH value of the second emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The mixture was centrifuged at 10,000 rpm for 30 min at 4°C. The resulting floating milky substance was the macadamia kernel oil body.

[0057] Example 6 (the only difference from Example 5 is that 20% sucrose is added in both steps (2) and (3)):

[0058] A method for extracting macadamia nut oil bodies comprises the following steps:

[0059] (1) Take 120g of macadamia kernels, weigh 1200g of distilled water, and then divide the distilled water into four equal parts (300g / part). Add the first part of distilled water and 120g of macadamia kernels into a blender and grind at 25000rpm for 2min. The ground slurry is filtered through four layers of gauze. The filter residue is mixed with the second part of distilled water, stirred again at the same speed in the blender for 2min and filtered to obtain the filter residue. Repeat the above operation for the filter residue twice more. The four filter slurries obtained are mixed together to obtain the macadamia kernel crude emulsion.

[0060] (2) 500 g of macadamia nut kernel crude emulsion was added with 100 g of sucrose and stirred until completely dissolved to obtain a first emulsion. The pH value of the first emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The pH-adjusted first emulsion was transferred to a centrifuge tube and centrifuged at 10,000 rpm for 30 min at 4°C to collect the floating milky substance.

[0061] (3) The collected supernatant was dispersed in distilled water at a mass ratio of 1:6, and the mixture was stirred to obtain a dispersion. Sucrose (20% by mass of the dispersion) was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH value of the second emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The mixture was centrifuged at 10,000 rpm for 30 min at 4°C. The resulting floating emulsion was the macadamia kernel oil body.

[0062] Example 7 (the only difference from Example 5 is that 30% sucrose is added in both step (2) and step (3)):

[0063] A method for extracting macadamia nut oil bodies comprises the following steps:

[0064] (1) Take 120g of macadamia kernels, weigh 1200g of distilled water, and then divide the distilled water into four equal parts (300g / part). Add the first part of distilled water and 120g of macadamia kernels into a blender and grind at 25000rpm for 2min. The ground slurry is filtered through four layers of gauze. The filter residue is mixed with the second part of distilled water, stirred again at the same speed in the blender for 2min and filtered to obtain the filter residue. Repeat the above operation for the filter residue twice more. The four filter slurries obtained are mixed together to obtain the macadamia kernel crude emulsion.

[0065] (2) 500 g of macadamia nut kernel crude emulsion was added with 150 g of sucrose and stirred until completely dissolved to obtain a first emulsion. The pH value of the first emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The pH-adjusted first emulsion was transferred to a centrifuge tube and centrifuged at 10,000 rpm for 30 min at 4°C to collect the floating milky substance.

[0066] (3) The collected supernatant was dispersed in distilled water at a mass ratio of 1:6, and the mixture was stirred to obtain a dispersion. Sucrose (30% by mass of the dispersion) was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH value of the second emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The mixture was centrifuged at 10,000 rpm for 30 min at 4°C. The resulting floating milky substance was the macadamia kernel oil body.

[0067] Example 8 (the only difference from Example 5 is that 40% sucrose is added in both steps (2) and (3)):

[0068] A method for extracting macadamia nut oil bodies comprises the following steps:

[0069] (1) Take 120g of macadamia kernels, weigh 1200g of distilled water, and then divide the distilled water into four equal parts (300g / part). Add the first part of distilled water and 120g of macadamia kernels into a blender and grind at 25000rpm for 2min. The ground slurry is filtered through four layers of gauze. The filter residue is mixed with the second part of distilled water, stirred again at the same speed in the blender for 2min and filtered to obtain the filter residue. Repeat the above operation for the filter residue twice more. The four filter slurries obtained are mixed together to obtain the macadamia kernel crude emulsion.

[0070] (2) 500 g of macadamia nut kernel crude emulsion was added with 200 g of sucrose and stirred until completely dissolved to obtain a first emulsion. The pH value of the first emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The pH-adjusted first emulsion was transferred to a centrifuge tube and centrifuged at 10,000 rpm for 30 min at 4°C to collect the floating milky substance.

[0071] (3) The collected supernatant was dispersed in distilled water at a mass ratio of 1:6, and the mixture was stirred to obtain a dispersion. Sucrose (40% by mass of the dispersion) was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH value of the second emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The mixture was centrifuged at 10,000 rpm for 30 min at 4°C. The resulting floating milky substance was the macadamia kernel oil body.

[0072] Comparative Example 1 (the only difference from Example 3 is that the pH is adjusted to 3 in both steps (2) and (3)):

[0073] A method for extracting macadamia nut oil bodies comprises the following steps:

[0074] (1) Take 120g of macadamia kernels, weigh 1200g of distilled water, and then divide the distilled water into four equal parts (300g / part). Add the first part of distilled water and 120g of macadamia kernels into a blender and grind at 25000rpm for 2min. The ground slurry is filtered through four layers of gauze. The filter residue is mixed with the second part of distilled water, stirred again at the same speed in the blender for 2min and filtered to obtain the filter residue. Repeat the above operation for the filter residue twice more. The four filter slurries obtained are mixed together to obtain the macadamia kernel crude emulsion.

[0075] (2) 500 g of macadamia nut kernel crude emulsion was added with 100 g of sucrose and stirred until completely dissolved to obtain a first emulsion. The pH value of the first emulsion was adjusted to 3 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The pH-adjusted first emulsion was transferred to a centrifuge tube and centrifuged at 10,000 rpm for 30 min at 4°C to collect the floating milky substance.

[0076] (3) The collected supernatant was dispersed in distilled water at a mass ratio of 1:6, and the mixture was stirred to obtain a dispersion. Sucrose (20% by mass of the dispersion) was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH value of the second emulsion was adjusted to 3 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The mixture was centrifuged at 10,000 rpm for 30 min at 4°C. The resulting floating emulsion was the macadamia kernel oil body.

[0077] Comparative Example 2 (the only difference from Example 3 is that the pH is adjusted to 4.5 in both steps (2) and (3):

[0078] A method for extracting macadamia nut oil bodies comprises the following steps:

[0079] (1) Take 120g of macadamia kernels, weigh 1200g of distilled water, and then divide the distilled water into four equal parts (300g / part). Add the first part of distilled water and 120g of macadamia kernels into a blender and grind at 25000rpm for 2min. The ground slurry is filtered through four layers of gauze. The filter residue is mixed with the second part of distilled water, stirred again at the same speed in the blender for 2min and filtered to obtain the filter residue. Repeat the above operation for the filter residue twice more. The four filter slurries obtained are mixed together to obtain the macadamia kernel crude emulsion.

[0080] (2) 500 g of macadamia nut kernel crude emulsion was added with 100 g of sucrose and stirred until completely dissolved to obtain a first emulsion. The pH value of the first emulsion was adjusted to 4.5 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The pH-adjusted first emulsion was transferred to a centrifuge tube and centrifuged at 10,000 rpm for 30 min at 4°C to collect the floating milky substance.

[0081] (3) The collected supernatant was dispersed in distilled water at a mass ratio of 1:6, and the mixture was stirred to obtain a dispersion. Sucrose (20% by mass of the dispersion) was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH value of the second emulsion was adjusted to 4.5 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The mixture was centrifuged at 10,000 rpm for 30 min at 4°C. The resulting floating emulsion was the macadamia kernel oil body.

[0082] Comparative Example 3 (the only difference from Example 3 is that the pH is adjusted to 11 in both steps (2) and (3):

[0083] A method for extracting macadamia nut oil bodies comprises the following steps:

[0084] (1) Take 120g of macadamia kernels, weigh 1200g of distilled water, and then divide the distilled water into four equal parts (300g / part). Add the first part of distilled water and 120g of macadamia kernels into a blender and grind at 25000rpm for 2min. The ground slurry is filtered through four layers of gauze. The filter residue is mixed with the second part of distilled water, stirred again at the same speed in the blender for 2min and filtered to obtain the filter residue. Repeat the above operation for the filter residue twice more. The four filter slurries obtained are mixed together to obtain the macadamia kernel crude emulsion.

[0085] (2) 500 g of macadamia nut kernel crude emulsion was added with 100 g of sucrose and stirred until completely dissolved to obtain a first emulsion. The pH value of the first emulsion was adjusted to 11 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The pH-adjusted first emulsion was transferred to a centrifuge tube and centrifuged at 10,000 rpm for 30 min at 4°C to collect the floating milky substance.

[0086] (3) The collected supernatant was dispersed in distilled water at a mass ratio of 1:6, and the mixture was stirred to obtain a dispersion. Sucrose (20% by mass of the dispersion) was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH value of the second emulsion was adjusted to 11 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The mixture was centrifuged at 10,000 rpm for 30 min at 4°C. The resulting floating emulsion was the macadamia kernel oil body.

[0087] Comparative Example 4 (the only difference from Example 5 is that sucrose is not added in steps (2) and (3)):

[0088] A method for extracting macadamia nut oil bodies comprises the following steps:

[0089] (1) Take 120g of macadamia kernels, weigh 1200g of distilled water, and then divide the distilled water into four equal parts (300g / part). Add the first part of distilled water and 120g of macadamia kernels into a blender and grind at 25000rpm for 2min. The ground slurry is filtered through four layers of gauze. The filter residue is mixed with the second part of distilled water, stirred again at the same speed in the blender for 2min and filtered to obtain the filter residue. Repeat the above operation for the filter residue twice more. The four filter slurries obtained are mixed together to obtain the macadamia kernel crude emulsion.

[0090] (2) 500 g of macadamia nut kernel crude emulsion was taken as the first emulsion, and the pH value of the first emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The pH-adjusted first emulsion was transferred to a centrifuge tube and centrifuged at 10,000 rpm for 30 min at 4°C to collect the floating emulsion;

[0091] (3) The collected supernatant was dispersed in distilled water at a mass ratio of 1:6, and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH value of the second emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The suspension was centrifuged at 10,000 rpm for 30 min at 4°C. The resulting floating emulsion was the macadamia kernel oil body.

[0092] Test example:

[0093] The extraction rate and protein content of macadamia kernel oil bodies obtained in Examples 3 and 4 and Comparative Examples 1 to 3 were tested respectively. The test results are shown in Figure 2 The protein components in the macadamia oil bodies obtained in Examples 3 and 4 and Comparative Examples 1 to 3 were reduced by SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). The test results are shown in Figure 3 .

[0094] The extraction rate and protein content of macadamia kernel oil bodies obtained in Examples 5 to 8 and Comparative Example 4 were tested respectively. The test results are shown in Figure 4 The protein components in the macadamia oil bodies obtained in Examples 5 to 8 were reduced using SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). The test results are shown in Figure 5 .

[0095] in Figure 3 and Figure 5 The protein with a molecular weight of 14-17 kDa is oleosomal protein, the protein with a molecular weight of 24-28 kDa is oleocalin, and the protein with a molecular weight of 35-60 kDa is oleosterol protein.

[0096] Depend on Figure 2 and Figure 3 It can be seen that when other conditions remain unchanged, the extraction rate of oil bodies can reach more than 85% when the pH is adjusted to 6.8 and 8 in steps (2) and (3), and the protein content in the oil bodies is less than 3.5%. At the same time, according to the results of SDS-PAGE ( Figure 3 ), oil body protein, oil body calcoprotein, oil body sterol protein can be retained, and the exogenous protein is less, that is, the protein content is mainly reduced by the exogenous protein adsorbed on the surface of the oil body, which proves that the extracted oil body has a high purity; when the pH is adjusted to 3 and 4.5 in steps (2) and (3), the protein content in the oil body is greater than 5%, and the SDS-PAGE results ( Figure 3 ) also showed that there were many protein aggregates near each protein band and they were difficult to distinguish, indicating that in addition to the oil body protein, oil body calcoprotein and oil body sterol protein on the oil body membrane, the oil body enrichment also contained a large amount of other impurity proteins, that is, more exogenous proteins. Among them, when the pH was 4.5, it was close to the isoelectric point of the oil body and aggregation occurred, and the exogenous proteins were not easy to be removed; when the pH was adjusted to 11 in both steps (2) and (3), the protein content in the oil body was less than 0.5%. Combined with the SDS-PAGE results ( Figure 3 ) indicates that the oil body protein, caleosin and steroleosin were seriously lost and the oil body structure was destroyed.

[0097] Combine Figure 4 and Figure 5It can be seen that when other conditions remain unchanged and sucrose is not added in steps (2) and (3), the extraction rate of oil bodies is lower than 65%, and the protein content in the oil bodies is close to 9%. The extraction rate is low and the exogenous protein is high.

[0098] 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 considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for extracting macadamia nut oil bodies, characterized by: The following steps are involved: (1) mixing macadamia nut kernels with a solvent, grinding the mixture, and filtering to obtain a macadamia nut kernel crude emulsion; (2) adding sucrose to the macadamia nut kernel crude emulsion obtained in step (1) to dissolve the emulsion to obtain a first emulsion, adjusting the pH of the first emulsion to 6.8-8, and then centrifuging to collect the supernatant; (3) dispersing the supernatant obtained in step (2) in a solvent to obtain a dispersion, then adding sucrose to the dispersion to dissolve it to obtain a second emulsion, adjusting the pH of the second emulsion to 6.8-8 and then centrifuging it to collect the floating milky substance, wherein the floating milky substance is the macadamia kernel oil body; in step (2), the centrifugation temperature is 0-4°C, the centrifugation speed is 8000-12000 rpm, and the centrifugation time is 25-40 min; in step (3), the centrifugation temperature is 0-4°C, the centrifugation speed is 8000-12000 rpm, and the centrifugation time is 25-40 min.

2. The method for extracting macadamia nut oil bodies according to claim 1, wherein: In step (1), the solvent is water, the macadamia nut kernels and water are mixed in a mass ratio of 1: (2-5) and then stirred and ground once, and a filter residue and a primary filtrate are obtained after filtration. The filter residue is added with water of the same mass as the primary stirring and grinding, and then stirred, ground and filtered. The filter residue is treated 2-5 times, and the filtrate obtained during the filter residue treatment is mixed with the primary filtrate to obtain the macadamia nut kernel crude emulsion.

3. The method for extracting macadamia nut oil bodies according to claim 2, wherein: The number of revolutions of the stirring and grinding is 18000-32000 rpm, and the time of the stirring and grinding is 1-5 min.

4. The method for extracting macadamia nut oil bodies according to claim 1, wherein: In step (2), the mass ratio of the added sucrose to the macadamia kernel crude emulsion is (0.1-0.3):

1.

5. The method for extracting macadamia nut oil bodies according to claim 1, wherein: In step (3), the solvent is water, and the floating matter is mixed with water in a mass ratio of 1:(5-8) and then stirred and dispersed to obtain the dispersion.

6. The method for extracting macadamia nut oil bodies according to claim 1, wherein: In step (3), the mass ratio of the added sucrose to the dispersion is (0.1-0.3):1.

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