A method of preparing a macadamia oil body emulsion gel

Abstract

The application discloses a method for preparing a macadamia oil body emulsion gel, comprising the following steps: (1) mixing a carrageenan solution and a konjac gum solution, then adding a resveratrol solution to obtain a mixed solution, shearing and dispersing the mixed solution after ice bath to obtain a composite polysaccharide particle dispersion; (2) mixing the composite polysaccharide particle dispersion obtained in the step (1), macadamia oil bodies and water to obtain a mixture, shearing and dispersing the mixture, and then ice bathing to obtain the macadamia oil body emulsion gel. The macadamia oil body emulsion gel prepared by the method has good antioxidant stability, structural strength and shear resistance, and can meet the shelf life and use requirements of related products.

Description

Technical Field

[0001] This invention belongs to the field of emulsion gel technology, and specifically relates to a method for preparing macadamia nut oil emulsion gel. Background Technology

[0002] Macadamia nuts are tree nuts native to southeastern Queensland, Australia. They are extremely rich in oil, mainly unsaturated fatty acids, especially monounsaturated fatty acids. Currently, the processing of macadamia nuts is mainly at the primary stage, and the development of deep processing is relatively slow. The potential added value of nuts has not been fully explored and enhanced. Researching and developing macadamia nut oil has become a new direction for future development.

[0003] Emulsion gels are semi-solid gels formed from emulsions through physical induction methods such as heating, acidification, and shearing. A continuous phase forms a three-dimensional network structure, which is then filled with a dispersed phase. These gels combine the advantages of both emulsions and gels. Their unique three-dimensional network structure can immobilize emulsified oil droplets within the network, thereby inhibiting oil droplet flocculation and aggregation. Compared to emulsions or gels alone, emulsion gels offer advantages such as structural stability, tunable viscoelasticity, the ability to encapsulate hydrophilic or hydrophobic components, and the ability to control the release rate and achieve targeted release by designing different gel matrices.

[0004] Emulsion gels can be applied in the development of cream-like foods or cosmetics. In food development, as a typical food system with amphiphilicity and stability, they not only meet people's needs for improved chewing properties and flavor, but also establish a good delivery system for bioactive substances, playing a wide and important role in improving the nutritional quality of food systems. Emulsion gels can also be used to replace animal fats in food, reducing the intake of saturated fats and trans fatty acids. In cosmetic development, emulsion gels can be used in products such as face creams, lotions, and masks, providing good spreadability and stability.

[0005] Research has shown that macadamia oil can be easily made into emulsion gels, but the macadamia oil emulsion gels prepared by existing processes have poor antioxidant stability, structural strength and shear resistance, which cannot meet the shelf life and usage requirements of related products. Summary of the Invention

[0006] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a method for preparing macadamia oil emulsion gels. The macadamia oil emulsion gels prepared by this method have good antioxidant stability, structural strength, and shear resistance, and can meet the shelf life and usage requirements of related products.

[0007] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0008] A method for preparing macadamia nut oil emulsion gel includes the following steps: (1) mixing carrageenan solution and konjac gum solution and adding resveratrol solution to obtain a mixture, and then dispersing the mixture by shearing after an ice bath to obtain a composite polysaccharide particle dispersion; (2) mixing the composite polysaccharide particle dispersion obtained in step (1), macadamia nut oil and water to obtain a mixture, and then dispersing the mixture by shearing after an ice bath to obtain the macadamia nut oil emulsion gel.

[0009] Preferably, in step (1), the carrageenan solution is obtained by mixing κ-carrageenan with water and then heating and dissolving, and the konjac gum solution is obtained by mixing konjac gum with water and then heating and dissolving, and the mass concentration of the carrageenan solution and the konjac gum solution is 1%-3%.

[0010] Preferably, in step (1), the carrageenan solution and the konjac gum solution are mixed at a mass ratio of (0.25-1):(0.25-1).

[0011] Preferably, the heating and dissolving refers to dissolving in a water bath at 70-90°C for 20-50 minutes.

[0012] Preferably, in step (1), the resveratrol solution is obtained by dissolving resveratrol powder in ethanol, and the mass concentration of the resveratrol solution is 0.2%-0.5%.

[0013] Preferably, in step (1), the mass concentration of resveratrol in the mixture is 0.03-0.08%.

[0014] Preferably, in step (1), the ice bath time is 8-15 minutes.

[0015] Preferably, in step (1), the shear dispersion refers to shearing at 5000-10000 rpm for 8-15 minutes.

[0016] Preferably, in step (2), the mass content of the composite polysaccharide particle dispersion in the mixture is 0.05%-0.6%.

[0017] More preferably, in step (2), the mass content of the composite polysaccharide particle dispersion in the mixture is 0.1%-0.4%.

[0018] Preferably, in step (2), the mass content of macadamia nut oil in the mixture is 40%-80%.

[0019] More preferably, in step (2), the mass content of macadamia nut oil in the mixture is 50%-75%.

[0020] Preferably, in step (2), the shear dispersion refers to shearing at 5000-10000 rpm for 8-15 minutes.

[0021] Preferably, in step (2), the ice bath time is 8-15 minutes.

[0022] Preferably, in step (2), the method for preparing the macadamia nut oil includes the following steps:

[0023] (1) Mix macadamia kernels with water, grind them, and filter to obtain macadamia kernel crude emulsion;

[0024] (2) Add sucrose to the macadamia nut crude emulsion at a mass ratio of 1:(0.1-0.3) to obtain the first emulsion. Adjust the pH of the first emulsion to 6-8 and centrifuge to collect the floating matter.

[0025] (3) Disperse the floating matter in water to obtain a dispersion, and then add sucrose to the dispersion at a mass ratio of dispersion to sucrose of 1:(0.1-0.3) to dissolve and obtain a second emulsion. Adjust the pH of the second emulsion to 6-8 and centrifuge to collect the floating emulsion. The floating emulsion is macadamia nut kernel oil.

[0026] The beneficial effects of this invention are: the method for preparing macadamia nut oil emulsion gel of this invention is to add composite polysaccharide particles prepared by κ-carrageenan and konjac gum to macadamia nut oil emulsion, and to combine it with resveratrol loaded with antioxidants, thereby obtaining macadamia nut oil emulsion gel with certain structural strength, strong shear resistance and storage stability, ensuring product quality and extending shelf life. Attached Figure Description

[0027] Figure 1 The graphs show the storage modulus G' and loss modulus G” of the macadamia oil emulsion gels prepared in Examples 3-6 and Comparative Example 1 of this invention as a function of stress.

[0028] Figure 2 The graphs show the viscosity of macadamia oil emulsion gels prepared in Examples 3-6 and Comparative Example 1 of this invention as a function of shear rate.

[0029] Figure 3 The storage modulus G' and loss modulus G” of the macadamia oil emulsion gels prepared in Examples 7, 4, and 8 of this invention and Comparative Examples 2 and 3 are curves showing the change of stress.

[0030] Figure 4 The graphs show the viscosity of macadamia oil emulsion gels prepared in Examples 7, 4, and 8 of this invention as a function of shear rate. Detailed Implementation

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

[0032] Example 1:

[0033] A method for preparing macadamia nut oil emulsion gel includes the following steps:

[0034] (1) Preparation of macadamia nut oil:

[0035] Take 120g of macadamia nuts and weigh 1200g of distilled water. Divide the distilled water into four equal parts (300g / part). Add the first part of distilled water and 120g of macadamia nuts to a mixer and grind at 25000rpm for 2 minutes. Filter the ground slurry through four layers of gauze. Mix the filter residue with the second part of distilled water and stir again in the mixer at the same speed for 2 minutes. Filter the residue again. Repeat the above operation twice more. Mix the four parts of slurry together to obtain macadamia nut crude emulsion.

[0036] Take 500g of macadamia nut kernel crude emulsion and add 100g of sucrose. Stir until completely dissolved to obtain the first emulsion. Adjust the pH of the first emulsion to 6.8 using 0.1mol / L HCl solution and 1mol / L NaOH solution. Transfer the first emulsion after pH adjustment to a centrifuge tube and centrifuge at 10000rpm for 30min at 4℃. Collect the floating emulsion.

[0037] The collected floating matter was dispersed in distilled water at a mass ratio of 1:6, and the dispersion was stirred to obtain a dispersion. Sucrose of 20% of the dispersion mass was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH of the second emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The emulsion was centrifuged at 10,000 rpm for 30 min at 4°C. The final floating emulsion was macadamia nut kernel oil, which was set aside for later use.

[0038] (2) Preparation of resveratrol solution:

[0039] Resveratrol powder was dissolved in ethanol to prepare a 0.2% resveratrol solution for later use.

[0040] (3) Preparation of κ-carrageenan solution and konjac gum solution:

[0041] Dissolve κ-carrageenan and konjac gum powders separately in distilled water, and heat in a water bath at 70°C for 50 minutes to prepare κ-carrageenan and konjac gum solutions with a mass concentration of 1%.

[0042] (4) Mix κ-carrageenan solution and konjac gum solution at a mass ratio of 1:0.25, add resveratrol solution to obtain a mixture with a resveratrol mass concentration of 0.03%. After ice bath for 8 min, shear at 5000 rpm for 15 min in a disperser to obtain a composite polysaccharide particle dispersion.

[0043] (5) The composite polysaccharide particle dispersion, macadamia oil body and water are mixed to obtain a mixture. The mass content of the composite polysaccharide particle dispersion in the mixture is 0.05% and the mass content of the macadamia oil body is 40%. The mixture is sheared at 5000 rpm for 15 min in a disperser and then placed in an ice bath for 8 min to obtain macadamia oil body emulsion gel.

[0044] Example 2:

[0045] A method for preparing macadamia nut oil emulsion gel includes the following steps:

[0046] (1) Preparation of macadamia nut oil:

[0047] Take 120g of macadamia nuts and weigh 1200g of distilled water. Divide the distilled water into four equal parts (300g / part). Add the first part of distilled water and 120g of macadamia nuts to a mixer and grind at 25000rpm for 2 minutes. Filter the ground slurry through four layers of gauze. Mix the filter residue with the second part of distilled water and stir again in the mixer at the same speed for 2 minutes. Filter the residue again. Repeat the above operation twice more. Mix the four parts of slurry together to obtain macadamia nut crude emulsion.

[0048] Take 500g of macadamia nut kernel crude emulsion and add 100g of sucrose. Stir until completely dissolved to obtain the first emulsion. Adjust the pH of the first emulsion to 6.8 using 0.1mol / L HCl solution and 1mol / L NaOH solution. Transfer the first emulsion after pH adjustment to a centrifuge tube and centrifuge at 10000rpm for 30min at 4℃. Collect the floating emulsion.

[0049] The collected floating matter was dispersed in distilled water at a mass ratio of 1:6, and the dispersion was stirred to obtain a dispersion. Sucrose of 20% of the dispersion mass was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH of the second emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The emulsion was centrifuged at 10,000 rpm for 30 min at 4°C. The final floating emulsion was macadamia nut kernel oil, which was set aside for later use.

[0050] (2) Preparation of resveratrol solution:

[0051] Resveratrol powder was dissolved in ethanol to prepare a 0.5% resveratrol solution for later use.

[0052] (3) Preparation of κ-carrageenan solution and konjac gum solution:

[0053] Dissolve κ-carrageenan and konjac gum powders separately in distilled water, and heat in a 90°C water bath for 20 minutes to prepare κ-carrageenan and konjac gum solutions with a mass concentration of 3%.

[0054] (4) Mix κ-carrageenan solution and konjac gum solution at a mass ratio of 1:1, add resveratrol solution to obtain a mixture with a resveratrol mass concentration of 0.08%. After ice bath for 15 min, shear at 10000 rpm for 8 min in a disperser to obtain a composite polysaccharide particle dispersion.

[0055] (5) The composite polysaccharide particle dispersion, macadamia oil body and water were mixed to obtain a mixture. The mass content of the composite polysaccharide particle dispersion in the mixture was 0.6% and the mass content of the macadamia oil body was 80%. The mixture was sheared at 10000 rpm for 8 min in a disperser and then placed in an ice bath for 15 min to obtain macadamia oil body emulsion gel.

[0056] Example 3:

[0057] A method for preparing macadamia nut oil emulsion gel includes the following steps:

[0058] (1) Preparation of macadamia nut oil:

[0059] Take 120g of macadamia nuts and weigh 1200g of distilled water. Divide the distilled water into four equal parts (300g / part). Add the first part of distilled water and 120g of macadamia nuts to a mixer and grind at 25000rpm for 2 minutes. Filter the ground slurry through four layers of gauze. Mix the filter residue with the second part of distilled water and stir again in the mixer at the same speed for 2 minutes. Filter the residue again. Repeat the above operation twice more. Mix the four parts of slurry together to obtain macadamia nut crude emulsion.

[0060] Take 500g of macadamia nut kernel crude emulsion and add 100g of sucrose. Stir until completely dissolved to obtain the first emulsion. Adjust the pH of the first emulsion to 6.8 using 0.1mol / L HCl solution and 1mol / L NaOH solution. Transfer the first emulsion after pH adjustment to a centrifuge tube and centrifuge at 10000rpm for 30min at 4℃. Collect the floating emulsion.

[0061] The collected floating matter was dispersed in distilled water at a mass ratio of 1:6, and the dispersion was stirred to obtain a dispersion. Sucrose of 20% of the dispersion mass was added to the dispersion and stirred thoroughly to break up the aggregates to obtain a second emulsion. The pH of the second emulsion was adjusted to 6.8 with 0.1 mol / L HCl solution and 1 mol / L NaOH solution. The emulsion was centrifuged at 10,000 rpm for 30 min at 4°C. The final floating emulsion was macadamia nut kernel oil, which was set aside for later use.

[0062] (2) Preparation of resveratrol solution:

[0063] Resveratrol powder was dissolved in ethanol to prepare a 0.4% resveratrol solution for later use.

[0064] (3) Preparation of κ-carrageenan solution and konjac gum solution:

[0065] Dissolve κ-carrageenan and konjac gum powders separately in distilled water, and heat in an 80°C water bath for 30 minutes to prepare κ-carrageenan and konjac gum solutions with a mass concentration of 2%.

[0066] (4) Mix κ-carrageenan solution and konjac gum solution at a mass ratio of 1:1, add resveratrol solution to obtain a mixture with a resveratrol mass concentration of 0.05%. After ice bath for 10 min, shear at 8000 rpm for 10 min in a disperser to obtain a composite polysaccharide particle dispersion.

[0067] (5) The mixture of the composite polysaccharide particle dispersion, macadamia oil and water is mixed to obtain a mixture. The mass content of the composite polysaccharide particle dispersion in the mixture is 0.1%, and the mass content of the macadamia oil is 75%. The mixture is sheared at 8000 rpm for 10 min in a disperser and then placed in an ice bath for 10 min to obtain macadamia oil emulsion gel.

[0068] Example 4:

[0069] A method for preparing macadamia nut oil emulsion gel differs from Example 3 only in that the mass content of the composite polysaccharide particle dispersion in the mixture in step (5) is 0.2%, while the other steps and parameters are exactly the same as in Example 3.

[0070] Example 5:

[0071] A method for preparing macadamia nut oil emulsion gel differs from Example 3 only in that the mass content of the composite polysaccharide particle dispersion in the mixture in step (5) is 0.3%, while the other steps and parameters are exactly the same as in Example 3.

[0072] Example 6:

[0073] A method for preparing macadamia nut oil emulsion gel differs from Example 3 only in that the mass content of the composite polysaccharide particle dispersion in the mixture in step (5) is 0.4%, while the other steps and parameters are exactly the same as in Example 3.

[0074] Example 7:

[0075] A method for preparing macadamia nut oil emulsion gel differs from Example 4 only in that in step (4), κ-carrageenan solution and konjac gum solution are mixed at a mass ratio of 1:0.5. All other steps and parameters are exactly the same as in Example 4.

[0076] Example 8:

[0077] A method for preparing macadamia nut oil emulsion gel differs from Example 4 only in that in step (4), κ-carrageenan solution and konjac gum solution are mixed at a mass ratio of 0.5:1. All other steps and parameters are exactly the same as in Example 4.

[0078] Comparative Example 1:

[0079] A method for preparing macadamia nut oil emulsion gel, which differs from Example 3 only in that no complex polysaccharide particle dispersion is added to the mixture in step (5), while the other steps and parameters are exactly the same as in Example 3.

[0080] Comparative Example 2:

[0081] A method for preparing macadamia nut oil emulsion gel differs from Example 4 only in that konjac gum solution is not added in step (4), and only κ-carrageenan solution and resveratrol solution are mixed to obtain a mixture. Other steps and parameters are exactly the same as in Example 4.

[0082] Comparative Example 3:

[0083] A method for preparing macadamia nut oil emulsion gel differs from Example 4 only in that κ-carrageenan solution is not added in step (4), and only konjac gum solution and resveratrol solution are mixed to obtain a mixture. Other steps and parameters are exactly the same as in Example 4.

[0084] Comparative Example 4:

[0085] A method for preparing macadamia nut oil emulsion gel, which differs from Example 4 only in that resveratrol solution is not added in step (4), while the other steps and parameters are exactly the same as in Example 4.

[0086] Experimental example:

[0087] I. Test on the properties of macadamia nut oil emulsion gel.

[0088] 1. Test on the effect of different amounts of compound polysaccharide particle dispersions on the gel properties of macadamia nut oil emulsions.

[0089] The rheological properties of the macadamia nut oil emulsion gels prepared in Examples 3-6 and Comparative Example 1 were tested under stress scanning and shear scanning, respectively. The test results are as follows: Figure 1-2 As shown, the gel-sol transition stress τ of the macadamia oil emulsion gels prepared in Examples 3-6 and Comparative Example 1 of this invention was tested. f and yield stress τ y The results are shown in Table 1 below.

[0090] Table 1: Test Results

[0091] <![CDATA[τ f (Well)]]> <![CDATA[τ y (Well)]]> Comparative Example 1 8.1 3.3 Example 3 46.6 25.6 Example 4 58.6 36.3 Example 5 31.5 19.2 Example 6 31.5 18.3

[0092] Depend on Figure 1 It can be seen that, under different amounts of added composite polysaccharide particle dispersion, the prepared macadamia oil emulsion gel has an obvious linear viscoelastic region, and the storage modulus G' in the linear viscoelastic range is higher than the loss modulus G", indicating that the macadamia oil emulsion forms a solid gel under different concentrations of composite polysaccharide particles.

[0093] Combination Figure 1 As shown in Table 1, the oil emulsion gel without the addition of the complex polysaccharide particle dispersion (Comparative Example 1) has the smallest linear viscoelastic region and its yield stress τ y The modulus and emulsion gel with added composite polysaccharide particle dispersion were significantly lower than those of the emulsion gel, indicating that its internal structure was weaker. Therefore, adding the specific composite polysaccharide particle dispersion of this invention can significantly improve the structural strength of the emulsion gel. When the mass content of the added composite polysaccharide particle dispersion was 0.1% (Example 3), the modulus of the oil emulsion gel was significantly improved. When the mass content of the added composite polysaccharide particle dispersion reached 0.2% (Example 4), the modulus, linear viscoelastic region, and yield stress τ of the emulsion gel were significantly improved. y All values ​​reached their maximum and were much higher than the corresponding values ​​of other concentrations of emulsion gel, indicating that the oil emulsion gel had the greatest structural strength at this concentration. When the mass content of the added composite polysaccharide particle dispersion was 0.3% (Example 5) and 0.4% (Example 6), the modulus curves of the oil emulsion gel at the two concentrations almost overlapped, indicating that when the amount of composite polysaccharide particle dispersion added was higher than 0.3%, the influence of particles on the structure tended to be stable.

[0094] Depend on Figure 2It can be seen that all samples exhibited shear thinning under different amounts of compound polysaccharide particle dispersion. However, the static apparent viscosity and apparent viscosity under shear of the oil emulsion gel with added compound polysaccharide particles were much higher than those of the oil emulsion gel without added compound polysaccharide particles, indicating that the addition of compound polysaccharide particles can greatly improve the shear resistance of the oil emulsion gel. For the oil emulsion gel without the addition of complex polysaccharide particles (Comparative Example 1), its static apparent viscosity was 17.6 Pa·s, which rapidly decreased to below 10 Pa·s after shearing. Under weaker structural strength, the oil emulsion gel exhibited lower static viscosity and became thinner under shearing. After adding the specific complex polysaccharide particles of this invention, the static apparent viscosity of the oil emulsion gel rapidly increased. When the mass content of the added complex polysaccharide particle dispersion was 0.2% (Example 4), the static apparent concentration of the oil emulsion gel was the highest, at 162 Pa·s, which is more than 10 times the static viscosity of the emulsion gel without the addition of microcolloid particles (Comparative Example 1). This is related to the stronger structure constructed by the oil molecules and microcolloid particles. At higher shear rates, the emulsion gels with the addition of complex polysaccharide particle dispersion at 0.2% (Example 4) and 0.4% (Example 6) both exhibited higher apparent viscosity and higher shear resistance at both concentrations.

[0095] 2. Test on the effect of different ratios of κ-carrageenan and konjac gum solutions in the dispersion of composite polysaccharide particles on the emulsion gel properties of macadamia nut oil.

[0096] The rheological properties of the macadamia nut oil emulsion gels prepared in Examples 7, 4, and 8 of this invention, and Comparative Examples 2 and 3, were tested under stress scanning and shear scanning, respectively. The test results are as follows: Figure 3-4 As shown, the gel-sol transition stress τ of the macadamia oil emulsion gels prepared in Examples 7, 4, 8 and Comparative Examples 2 and 3 of this invention was tested. f and yield stress τ y The results are shown in Table 2 below.

[0097] Table 2: Test Results

[0098] <![CDATA[τ f (Well)]]> <![CDATA[τ y (Well)]]> Comparative Example 2 17.2 9.2 Example 7 46.2 32.3 Example 4 58.6 36.3 Example 8 20.5 12.2 Comparative Example 3 39.2 24.5

[0099] Depend on Figure 3 It can be seen that under different ratios of κ-carrageenan solution and konjac gum solution, the prepared macadamia oil emulsion gel has an obvious linear viscoelastic region, and the storage modulus G' in the linear viscoelastic range is higher than the loss modulus G', indicating that the macadamia oil emulsion forms a solid gel under different ratios of κ-carrageenan solution and konjac gum solution.

[0100] Combination Figure 3As shown in Table 2, when the composite polysaccharide particle dispersion does not contain konjac gum (Comparative Example 2), the prepared emulsion has the lowest gel modulus and the lowest yield stress τ. y The modulus of the oil emulsion gel is less than 10 Pa, indicating that the microparticles prepared solely using κ-carrageenan cannot form a high-strength emulsion gel with macadamia nut oil molecules. As the proportion of konjac gum increased with the addition of konjac gum to the composite polysaccharide particle dispersion, the modulus of the oil emulsion gel exhibited a pattern of first increasing and then decreasing. At composite ratios of 1:0.5 (Example 7) and 1:1 (Example 4), the moduli of the emulsion gels were similar, and they also had similar yield stresses τ. y The linear viscoelastic region indicates that the external force resistance of the emulsion gel is similar under the two composite ratios. When the composite ratio of κ-carrageenan solution and konjac gum solution is 0.5:1 (Example 8), the content of konjac gum in the microparticles is higher than that of κ-carrageenan. At this time, the modulus and yield stress τ of the emulsion gel are similar. y Gel-sol transition point stress τ f All showed a significant decline, indicating a weakening ability of the emulsion gel to resist external forces. This suggests that κ-carrageenan played a dominant role in stabilizing the macadamia oil emulsion gel when the microparticles prepared by κ-carrageenan and konjac gum were combined. When the composite ratio of κ-carrageenan solution to konjac gum solution was 0:1 (Comparative Example 3), the modulus of the emulsion gel rebounded, and the yield stress also increased accordingly. This indicates that the emulsion gel prepared by the microparticles under this composite ratio showed a significant rebound in resistance to external forces. At this time, the microparticles were composed solely of konjac gum. The microparticles under this composite ratio may be composed of polysaccharide gel particles and polysaccharide chains. The resulting emulsion gel has a relatively compact spatial structure and can provide a certain degree of resistance to external pressure.

[0101] Depend on Figure 4 It can be seen that macadamia oil emulsion gels with different κ-carrageenan and konjac gum solutions all exhibit shear-thinning pseudoplastic fluid properties. When the κ-carrageenan to konjac gum solution ratio is 1:0 (Comparative Example 2), the emulsion gel has poor shear resistance, and the viscosity of the gel rapidly drops below 10 Pa·s at low shear rates, indicating that κ-carrageenan particles alone are ineffective in maintaining the viscosity stability of the oil emulsion gel. When the κ-carrageenan to konjac gum solution ratio is 1:0.5 to 0:1, the viscosity of the emulsion gel in each ratio is higher than that in the 1:0 ratio, and the viscosity is higher at shear rates above 15 s⁻¹. -1 The similar viscosities indicate that adding a certain amount of konjac gum to the microparticles is beneficial to improving the viscosity of the emulsion gel. However, at higher shear rates, the microparticle composite ratio has little effect on the shear resistance of the macadamia oil emulsion gel.

[0102] II. Antioxidant stability test of macadamia nut oil emulsion gel.

[0103] The oxidative stability of the macadamia oil emulsion gels prepared in Examples 3-8 and Comparative Examples 1-4 of this invention was tested after ultraviolet irradiation. Specifically, the gels were irradiated for 15 hours under a 125W ultraviolet lamp with a wavelength of 365nm. The peroxide value was tested as follows: 0.5g of emulsion gel was vortexed in 1.5mL of a mixture of isooctane and isopropanol (3:1, v / v) for 30s, then centrifuged at 10000rpm for 2min. 200μL of the organic phase was added to 2.8mL of a mixture of methanol and n-butanol (2:1, v / v) and mixed well. 15μL of a pre-prepared 3.94M ammonium thiocyanate solution and 15μL of a 0.132M ferrous solution were added. After reacting in the dark for 20min, the absorbance was measured at 510nm using an ultraviolet spectrophotometer.

[0104] The method for testing malondialdehyde (MDA) content was as follows: 0.1 g of the emulsion was added to 1.9 mL of distilled water and 4 mL of TBA reagent, boiled in boiling water for 15 min, cooled at room temperature, and then centrifuged at 10000 rpm for 15 min. The supernatant was then collected and the absorbance was measured at 532 nm using a UV spectrophotometer. The lipid peroxide content and MDA content in the macadamia nut oil emulsion gel after UV irradiation are shown in Table 3 below.

[0105] Table 3. Results of antioxidant stability test

[0106]

[0107] Table 3 shows that the macadamia nut oil emulsion gel prepared by this invention has a lipid peroxide content of no more than 2762.1 mmol / kg and a malondialdehyde content of no more than 11.5 mmol / kg after UV irradiation testing, exhibiting excellent antioxidant stability. Comparing Example 3 with Comparative Example 1, it can be seen that when no composite polysaccharide particle dispersion is added during the preparation process, the antioxidant stability of the obtained macadamia nut oil emulsion gel decreases significantly. Comparing Example 4 with Comparative Examples 2-3, it can be seen that when either konjac gum solution or κ-carrageenan solution is missing from the composite polysaccharide particle dispersion during the preparation process, the antioxidant stability of the obtained macadamia nut oil emulsion gel decreases significantly. Comparing Example 4 with Comparative Example 4, it can be seen that when no resveratrol solution is added during the preparation process, the antioxidant stability of the obtained macadamia nut oil emulsion gel decreases significantly.

[0108] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing macadamia nut oil emulsion gel, characterized in that: Includes the following steps: (1) After mixing carrageenan solution and konjac gum solution, add resveratrol solution to obtain a mixture. After the mixture is placed in an ice bath, shear and disperse it to obtain a composite polysaccharide particle dispersion. (2) The composite polysaccharide particle dispersion obtained in step (1), macadamia oil body and water are mixed to obtain a mixture. The mixture is sheared and dispersed and then placed in an ice bath to obtain the macadamia oil body emulsion gel. In step (1), the carrageenan solution is obtained by mixing κ-carrageenan with water and then heating and dissolving it. The konjac gum solution is obtained by mixing konjac gum with water and then heating and dissolving it. The mass concentration of the carrageenan solution and the konjac gum solution is 1%-3%. The carrageenan solution and the konjac gum solution are mixed at a mass ratio of (0.25-1):(0.25-1). The mass concentration of resveratrol in the mixture is 0.03-0.08%.

2. The method for preparing macadamia nut oil emulsion gel according to claim 1, characterized in that: The heating and dissolving process refers to dissolving the material in a water bath at 70-90℃ for 20-50 minutes.

3. The method for preparing macadamia nut oil emulsion gel according to claim 1, characterized in that: In step (1), the resveratrol solution is obtained by dissolving resveratrol powder in ethanol, and the mass concentration of the resveratrol solution is 0.2%-0.5%.

4. The method for preparing macadamia nut oil emulsion gel according to claim 1, characterized in that: In step (1), the ice bath time is 8-15 minutes.

5. The method for preparing macadamia nut oil emulsion gel according to claim 1, characterized in that: In step (1), the shear dispersion refers to shearing at 5000-10000 rpm for 8-15 min.

6. The method for preparing macadamia nut oil emulsion gel according to claim 1, characterized in that: In step (2), the mass content of the composite polysaccharide particle dispersion in the mixture is 0.05%-0.6%.

7. The method for preparing macadamia nut oil emulsion gel according to claim 1, characterized in that: In step (2), the mass content of macadamia nut oil in the mixture is 40%-80%.

Images