Novel vegetable protein-polysaccharide composite nanoparticle-stabilized powdered oil and preparation method thereof

Abstract

The invention discloses novel vegetable protein-polysaccharide composite nanoparticle stable powdered oil and a preparation method thereof, and belongs to the technical field of powdered oil preparation. The preparation method of the novel vegetable protein-polysaccharide powdered oil comprises the following steps: adding water into vegetable protein, dispersing, stirring overnight, and hydrating to obtain vegetable protein dispersion liquid; adding water to disperse polysaccharide, stirring overnight and hydrating to obtain a polysaccharide dispersion liquid; mixing the vegetable protein dispersion liquid with the polysaccharide dispersion liquid, adjusting the pH value to be alkaline, heating, stirring, cooling, and adjusting the pH value to be neutral, so as to obtain vegetable protein-polysaccharide composite nanoparticle dispersion liquid; and adding an oil phase, shearing and emulsifying, homogenizing at high pressure, and finally spray-drying. According to the method, the vegetable protein-polysaccharide composite nanoparticles are prepared through the pH shift vegetable protein-polysaccharide mixture, the grease is encapsulated through spray drying, the stability of the grease is improved, the method can also be used for embedding curcumin and other active substances, and a new thought is provided for improving the stability of the active substances.

Description

Technical Field

[0001] The invention relates to the technical field of powdered oil preparation, and in particular to a novel powdered oil stabilized by plant protein-polysaccharide composite nanoparticles and a preparation method thereof. Background Art

[0002] Liquid oils are easily oxidized and deteriorate, and have poor fluidity, which limits their application in the food industry. One of the important technologies to extend the shelf life of oils is to use microencapsulation technology for spray drying. The two-step microencapsulation process, namely the emulsification of the core material and the drying of the emulsion, converts the liquid oil into a powdered solid. Microencapsulated powdered oils not only retain the characteristics of the oil itself, but also give the oil good water dispersibility, improve its thermal stability and oxidative stability, and are easy to transport and store.

[0003] However, lipid microencapsulation remains a challenge due to its high sensitivity to oxidation. To address this issue, a common strategy is to reduce the surface oil content of microcapsules by optimizing process conditions or adding additional synthetic or natural antioxidants to the aqueous or oil phase. The emergence of Pickering emulsions provides another solution to the oxidative instability of lipid microcapsules by manipulating the interfacial layer. Pickering emulsions are stabilized by solid particles instead of traditional amphiphilic surfactants. However, emulsions stabilized by single protein particles are often unstable and may undergo flocculation, aggregation, and even oil precipitation. Proteins and polysaccharides can interact to form composite nanoparticles with designable wettability, which is considered to be one of the most promising methods for preparing food-grade Pickering emulsion stabilizers from the bottom up. So far, a variety of protein-polysaccharide complexes have been used to prepare Pickering emulsions, but there are few reports on their application as spray drying raw materials for the production of powdered lipids. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a novel plant protein-polysaccharide composite nanoparticle-stabilized powdered oil and a preparation method thereof. The present invention prepares plant protein-polysaccharide composite nanoparticles by pH shifting the plant protein-polysaccharide mixture, and encapsulates the oil by spray drying, thereby improving the stability of the oil. The method can also be used to embed active substances such as curcumin, providing a new idea for improving the stability of active substances.

[0005] The technical solution of the present invention is as follows:

[0006] The first aspect of the present invention provides a method for preparing a novel powdered oil stabilized by plant protein-polysaccharide composite nanoparticles, the preparation method comprising the following steps:

[0007] S1: After the vegetable protein is dispersed in water, it is stirred overnight for hydration to obtain a vegetable protein dispersion.

[0008] S2: After dispersing the polysaccharide in water, stir overnight for hydration to obtain a polysaccharide dispersion.

[0009] S3: The plant protein dispersion of S1 and the polysaccharide dispersion of S2 are mixed to obtain a mixed solution, the pH is adjusted to alkaline, heated and stirred, cooled to room temperature, and then the pH is adjusted to neutral to obtain a plant protein-polysaccharide composite nanoparticle dispersion.

[0010] S4: Add the oil phase to the dispersion of plant protein-polysaccharide composite nanoparticles, shear emulsify to obtain a coarse emulsion, and then homogenize under high pressure to obtain a fine emulsion, spray dry the fine emulsion to obtain a powdered oil that is stable with plant protein-polysaccharide composite nanoparticles.

[0011] Preferably, in S1, the plant protein includes one or more of pea protein, peanut protein, soy protein, chickpea protein, oat protein, quinoa protein, potato protein, zein, and wheat prolamin; and the concentration of the plant protein dispersion is 1-5% (w / v).

[0012] Preferably, in S2, the polysaccharide comprises one or more of propylene glycol alginate, gum arabic, pectin, xanthan gum, konjac gum and sodium alginate; and the concentration of the polysaccharide dispersion is 1-5% (w / v).

[0013] Preferably, in S3, in the mixed solution, the mass ratio of plant protein to polysaccharide is 3-20:1.

[0014] Preferably, in S3, the step of adjusting the pH to alkaline is adjusting the pH to 9-12 using alkaline solution.

[0015] Preferably, the temperature of the heating and stirring is 70-90° C., and the time is 0.5-1.5 h; and the pH adjustment to neutral refers to adjusting the pH to 7.0 with an acid solution.

[0016] Preferably, in S4, the oil phase includes one or more of linseed oil, corn oil, soybean oil, peanut oil, rapeseed oil, olive oil, sesame oil, camellia oil, walnut oil, and fish oil; the mass ratio of the oil phase to the plant protein-polysaccharide composite nanoparticles is 1:5-3:1.

[0017] Preferably, in S4, the shear emulsification speed is 12000-15000 r / min, and the time is 4-8 min; the pressure of the high-pressure homogenization is 600-800 bar, and the number of cycles of the high-pressure homogenization is 2-4 times.

[0018] Preferably, in S4, the inlet air temperature of the spray drying is 140-170°C, the feed flow rate is 4-8 mL / min, and the air flow rate is 400-800 L / h.

[0019] The second aspect of the present invention provides a novel plant protein-polysaccharide composite nanoparticle-stabilized powdered oil prepared by the preparation method described in the first aspect.

[0020] The beneficial technical effects of the present invention are:

[0021] The present invention prepares protein-polysaccharide composite nanoparticle Pickering emulsion by pH shift, and combines it with spray drying to prepare powdered oil, thereby improving the stability of the oil and reducing the surface oil content of the powdered oil. At the same time, the method of the present invention can also be used to embed active substances such as curcumin, providing a new idea for improving the stability of active substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The particle sizes of the PPI-PGA composite nanoparticles and the emulsion after high pressure homogenization in the examples and comparative examples.

[0023] In the figure: A, particle size of PPI-PGA composite nanoparticles of Example and Comparative Example 1; B, particle size of the emulsion after high pressure homogenization of Example and Comparative Example 1.

[0024] Figure 2 The particle size distribution of the powdered fats prepared in Example 3 and Comparative Example 1.

[0025] In the figure: A, particle size distribution of powdered oil stabilized by plant protein nanoparticles in comparative example 1; B, particle size distribution of powdered oil stabilized by protein-polysaccharide composite nanoparticles in example 3.

[0026] Figure 3 The following are photos of the powdered fats of Example 3 and Comparative Example 2.

[0027] In the figure: A, sample picture of powdered grease of Comparative Example 2; B, sample picture of powdered grease of Example 3. DETAILED DESCRIPTION

[0028] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0029] The first aspect of the present invention provides a method for preparing a novel powdered oil stabilized by plant protein-polysaccharide composite nanoparticles, the preparation method comprising the following steps:

[0030] S1: After the vegetable protein is dispersed in water, it is stirred overnight for hydration to obtain a vegetable protein dispersion.

[0031] S2: After dispersing the polysaccharide in water, stir overnight for hydration to obtain a polysaccharide dispersion.

[0032] S3: The plant protein dispersion of S1 and the polysaccharide dispersion of S2 are mixed to obtain a mixed solution, the pH is adjusted to alkaline, heated and stirred, cooled to room temperature, and then the pH is adjusted to neutral to obtain a plant protein-polysaccharide composite nanoparticle dispersion.

[0033] S4: Add the oil phase to the dispersion of plant protein-polysaccharide composite nanoparticles, shear emulsify to obtain a coarse emulsion, and then homogenize under high pressure to obtain a fine emulsion, spray dry the fine emulsion to obtain a powdered oil that is stable with plant protein-polysaccharide composite nanoparticles.

[0034] It is understandable that the present invention, through pH shift, makes the protein first highly soluble under pH 12 conditions, the highly alkaline environment destroys the structural part of the protein molecule and unfolds, exposing the internal water group and active site, and then when the pH is adjusted back from alkaline to neutral, the protein gradually renatures and re-forms part of the secondary and tertiary structures. Intermolecular interactions may occur between the hydrophobic group and the exposed active group in this process, resulting in partial aggregation of the protein. Under neutral conditions, the exposure of the hydrophobic group and the formation of hydrogen bonds further enhance the interaction between the protein and the polysaccharide, thereby forming stable composite nanoparticles. The protein-polysaccharide composite nanoparticles prepared by pH shift are further prepared by Pickering emulsion combined with spray drying to obtain powdered oil, which improves the stability of the oil and reduces the surface oil content of the powdered oil. At the same time, the method of the present invention can also be used to embed active substances such as curcumin, providing a new idea for improving the stability of active substances.

[0035] In some embodiments, in S1, the plant protein includes one or more of pea protein, peanut protein, soy protein, chickpea protein, oat protein, quinoa protein, potato protein, zein, and wheat alcohol-soluble protein; the concentration of the plant protein dispersion is 1-5% (w / v), including but not limited to 1% (w / v), 1.5% (w / v), 2% (w / v), 2.5% (w / v), 3% (w / v), 3.5% (w / v), 4% (w / v), 4.5% (w / v), and 5% (w / v).

[0036] In some embodiments, in S2, the polysaccharide includes one or more of propylene glycol alginate, gum arabic, pectin, xanthan gum, konjac gum and sodium alginate; the concentration of the polysaccharide dispersion is 1-5% (w / v), including but not limited to 1% (w / v), 1.5% (w / v), 2% (w / v), 2.5% (w / v), 3% (w / v), 3.5% (w / v), 4% (w / v), 4.5% (w / v), and 5% (w / v).

[0037] In some embodiments, in S3, in the mixed solution, the mass ratio of plant protein to polysaccharide is 3-20:1, including but not limited to 3:1, 5:1, 10:1, 15:1, and 20:1.

[0038] In some embodiments, in S3, adjusting the pH to alkaline is to adjust the pH to 9-12 with alkaline solution, including but not limited to 9, 10, 11, and 12.

[0039] In some embodiments, the temperature of the heating and stirring is 70-90°C, including but not limited to 70°C, 75°C, 80°C, 85°C, 90°C, and the time is 0.5-1.5h, including but not limited to 0.5h, 1h, 1.5h; and adjusting the pH to neutral means adjusting the pH to 7.0 with an acid solution.

[0040] It is understandable that the present invention prepares protein-polysaccharide composite nanoparticles by pH offset to prepare Pickering emulsion, and the protein and polysaccharide mixed solution is subjected to alkaline heat treatment, and the protein molecules are partially dissociated, and the secondary and tertiary structures are destroyed, exposing more hydrophobic regions and active groups. Heating further promotes protein deconstruction and interaction between molecules. Under alkaline conditions, polysaccharide molecules usually remain stable, but their interaction with protein molecules will be enhanced due to changes in protein charge. When the system is cooled and adjusted back to pH 7, the protein is positively charged or close to the equilibrium point, and many polysaccharides (such as anionic polysaccharides) are negatively charged, which promotes electrostatic interaction and the formation of complexes. During heating and cooling, protein and polysaccharide molecules may separate or aggregate together, resulting in microscale or nanoscale particle formation.

[0041] In some embodiments, in S4, the oil phase includes one or more of linseed oil, corn oil, soybean oil, peanut oil, rapeseed oil, olive oil, sesame oil, camellia oil, walnut oil, and fish oil; the mass ratio of the oil phase to the plant protein-polysaccharide composite nanoparticles is 1:5-3:1, including but not limited to 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, wherein the mass of the plant protein-polysaccharide composite nanoparticles is the sum of the masses of the plant protein and the polysaccharide.

[0042] In some embodiments, in S4, the shear emulsification speed is 12000-15000 r / min, including but not limited to 12000 r / min, 13000 r / min, 14000 r / min, 15000 r / min, and the time is 4-8 min, including but not limited to 4 min, 5 min, 6 min, 7 min, 8 min; the pressure of the high-pressure homogenization is 600-800 bar, including but not limited to 600 bar, 700 bar, 800 bar, and the number of cycles of high-pressure homogenization is 2-4 times, including but not limited to 2 times, 3 times, and 4 times.

[0043] In some embodiments, in S4, the inlet air temperature of the spray drying is 140-170°C, including but not limited to 140°C, 150°C, 160°C, and 170°C; the feed flow rate is 4-8mL / min, including but not limited to 4mL / min, 5mL / min, 6mL / min, 7mL / min, and 8mL / min; the air flow rate is 400-800L / h, including but not limited to 400L / h, 500L / h, 600L / h, 700L / h, and 800L / h.

[0044] It is understood that the present invention can prepare powdered oil by spray drying Pickering emulsion to isolate internal oil from air, slow down the oxidation rate of oil, and facilitate transportation and storage. The powdered oil prepared by this method can be used to control the release of core material and cover the odor of core material (such as fish oil). It can also be used for embedding and delivery of oil-soluble active substances, which can effectively inhibit the volatilization and oxidation deterioration of active substances and prolong the storage period.

[0045] The second aspect of the present invention provides a novel plant protein-polysaccharide composite nanoparticle-stabilized powdered oil prepared by the preparation method described in the first aspect.

[0046] In the present invention, the theoretical oil loading is the actual added oil phase (core material) mass: wall material (i.e. composite nanoparticle mass). For example, when the core-to-wall ratio is 1:1, the theoretical oil loading is 50%.

[0047] The following are specific embodiments.

[0048] Example 1

[0049] Powdered fat, the preparation method is as follows:

[0050] (1) Preparation of composite nanoparticle dispersion

[0051] The pea protein isolate (PPI) was dispersed in deionized water to obtain a 2% (w / v) pea protein isolate solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0052] Propylene glycol alginate (PGA) was dispersed in deionized water to obtain a 2% (w / v) PGA solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0053] Then, the mixture was mixed at a mass ratio of PPI:PGA of 20:1 and stirred at room temperature for 1 hour. The mixed solution was adjusted to pH 12 with 6M NaOH solution, stirred at 85°C for 1 hour, cooled to room temperature, and then adjusted to pH 7 with HCL, stirred for 1 hour to obtain a protein-polysaccharide composite nanoparticle dispersion.

[0054] (2) Preparation of Pickering emulsion and powdered oil

[0055] Linseed oil was used as the emulsion oil phase, and the linseed oil and protein-polysaccharide composite nanoparticle dispersion were mixed at a mass ratio of 1:1, and high-speed shearing was performed at 14000 rpm for 5 minutes to obtain a crude emulsion.

[0056] The obtained crude emulsion was circulated and homogenized under high pressure for 3 times at 700 bar.

[0057] Use a spray dryer, set the inlet air temperature of the spray drying process to 150°C, the feed flow rate to 6mL / min, and the air flow rate to 600L / h, spray dry the liquid feed after high-pressure homogenization to obtain powdered oil.

[0058] Example 2

[0059] Powdered fat, the preparation method is as follows:

[0060] (1) Preparation of composite nanoparticle dispersion

[0061] The pea protein isolate (PPI) was dispersed in deionized water to obtain a 2% (w / v) pea protein isolate solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0062] Propylene glycol alginate (PGA) was dispersed in deionized water to obtain a 2% (w / v) PGA solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0063] Then, the mixture was mixed at a mass ratio of PPI:PGA of 15:1 and stirred at room temperature for 1 hour. The mixed solution was adjusted to pH 12 with 6M NaOH solution, stirred at 85°C for 1 hour, cooled to room temperature, and then adjusted to pH 7 with HCL, stirred for 1 hour to obtain a protein-polysaccharide composite nanoparticle dispersion.

[0064] (2) Preparation of Pickering emulsion and powdered oil

[0065] Linseed oil was used as the emulsion oil phase, and the mass ratio of linseed oil to protein-polysaccharide composite nanoparticles was 1:1. The linseed oil and protein-polysaccharide composite nanoparticles dispersion were mixed and high-speed sheared at 14000 rpm for 5 minutes to obtain a crude emulsion.

[0066] The obtained crude emulsion was subjected to a high pressure homogenization process at 700 bar for 3 cycles.

[0067] Use a spray dryer, set the inlet air temperature of the spray drying process to 150°C, the feed flow rate to 6mL / min, and the air flow rate to 600L / h, spray dry the liquid feed after high-pressure homogenization to obtain powdered oil.

[0068] Example 3

[0069] Powdered fat, the preparation method is as follows:

[0070] (1) Preparation of composite nanoparticle dispersion

[0071] The pea protein isolate (PPI) was dispersed in deionized water to obtain a 2% (w / v) pea protein isolate solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0072] Propylene glycol alginate (PGA) was dispersed in deionized water to obtain a 2% (w / v) PGA solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0073] Then, the mixture was mixed at a mass ratio of PPI:PGA of 10:1 and stirred at room temperature for 1 hour. The mixed solution was adjusted to pH 12 with 6M NaOH solution, stirred at 85°C for 1 hour, cooled to room temperature, and then adjusted to pH 7 with HCL, stirred for 1 hour to obtain a protein-polysaccharide composite nanoparticle dispersion.

[0074] (2) Preparation of Pickering emulsion and powdered oil

[0075] Linseed oil was used as the emulsion oil phase, and the mass ratio of linseed oil to protein-polysaccharide composite nanoparticles was 1:1. The linseed oil and protein-polysaccharide composite nanoparticles dispersion were mixed and high-speed sheared at 14000 rpm for 5 minutes to obtain a crude emulsion.

[0076] The obtained crude emulsion was subjected to a high pressure homogenization process at 700 bar for 3 cycles.

[0077] Use a spray dryer, set the inlet air temperature of the spray drying process to 150°C, the feed flow rate to 6mL / min, and the air flow rate to 600L / h, spray dry the liquid feed after high-pressure homogenization to obtain powdered oil.

[0078] Example 4

[0079] Powdered fat, the preparation method is as follows:

[0080] (1) Preparation of composite nanoparticle dispersion

[0081] The pea protein isolate (PPI) was dispersed in deionized water to obtain a 2% (w / v) pea protein isolate solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0082] Propylene glycol alginate (PGA) was dispersed in deionized water to obtain a 2% (w / v) PGA solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0083] Then, the mixture was mixed at a mass ratio of PPI:PGA of 5:1 and stirred at room temperature for 1 hour. The mixed solution was adjusted to pH 12 with 6M NaOH solution, stirred at 85°C for 1 hour, cooled to room temperature, and then adjusted to pH 7 with HCL and stirred for 1 hour to obtain a protein-polysaccharide composite nanoparticle dispersion.

[0084] (2) Preparation of Pickering emulsion and powdered oil

[0085] Linseed oil was used as the emulsion oil phase, and the mass ratio of linseed oil to protein-polysaccharide composite nanoparticles was 1:1. The linseed oil and protein-polysaccharide composite nanoparticles dispersion were mixed and high-speed sheared at 14000 rpm for 5 minutes to obtain a crude emulsion.

[0086] The obtained crude emulsion was subjected to a high pressure homogenization process at 700 bar for 3 cycles.

[0087] Use a spray dryer, set the inlet air temperature of the spray drying process to 150°C, the feed flow rate to 6mL / min, and the air flow rate to 600L / h, spray dry the liquid feed after high-pressure homogenization to obtain powdered oil.

[0088] Example 5

[0089] Powdered fat, the preparation method is as follows:

[0090] (1) Preparation of composite nanoparticle dispersion

[0091] The pea protein isolate (PPI) was dispersed in deionized water to obtain a 2% (w / v) pea protein isolate solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0092] Propylene glycol alginate (PGA) was dispersed in deionized water to obtain a 2% (w / v) PGA solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0093] Then, the mixture was mixed at a mass ratio of PPI:PGA of 3:1 and stirred at room temperature for 1 hour. The mixed solution was adjusted to pH 12 with 6M NaOH solution, stirred at 85°C for 1 hour, cooled to room temperature, and then adjusted to pH 7 with HCL, stirred for 1 hour to obtain a protein-polysaccharide composite nanoparticle dispersion.

[0094] (2) Preparation of Pickering emulsion and powdered oil

[0095] Linseed oil was used as the emulsion oil phase, and the mass ratio of linseed oil to protein-polysaccharide composite nanoparticles was 1:1. The linseed oil and protein-polysaccharide composite nanoparticle dispersion were mixed and sheared at 14000 rpm for 5 minutes to obtain a crude emulsion.

[0096] The obtained crude emulsion was subjected to a high pressure homogenization process at 700 bar for 3 cycles.

[0097] Use a spray dryer, set the inlet air temperature of the spray drying process to 150°C, the feed flow rate to 6mL / min, and the air flow rate to 600L / h, spray dry the liquid feed after high-pressure homogenization to obtain powdered oil.

[0098] Example 6

[0099] Powdered fat, the preparation method is as follows:

[0100] (1) Preparation of composite nanoparticle dispersion

[0101] The pea protein isolate (PPI) was dispersed in deionized water to obtain a 2% (w / v) pea protein isolate solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0102] Propylene glycol alginate (PGA) was dispersed in deionized water to obtain a 2% (w / v) PGA solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0103] Then, the mixture was mixed at a mass ratio of PPI:PGA of 10:1 and stirred at room temperature for 1 hour. The mixed solution was adjusted to pH 12 with 6M NaOH solution, stirred at 85°C for 1 hour, cooled to room temperature, and then adjusted to pH 7 with HCL, stirred for 1 hour to obtain a protein-polysaccharide composite nanoparticle dispersion.

[0104] (2) Preparation of Pickering emulsion and powdered oil

[0105] Corn oil was used as the emulsion oil phase, and the mass ratio of corn oil to protein-polysaccharide composite nanoparticles was 1:1. Corn oil and protein-polysaccharide composite nanoparticle dispersion were mixed and high-speed sheared at 14000 rpm for 5 min to obtain a crude emulsion.

[0106] The obtained crude emulsion was subjected to a high pressure homogenization process at 700 bar for 3 cycles.

[0107] Use a spray dryer, set the inlet air temperature of the spray drying process to 150°C, the feed flow rate to 6mL / min, and the air flow rate to 600L / h, spray dry the liquid feed after high-pressure homogenization to obtain powdered oil.

[0108] Example 7

[0109] Powdered fat, the preparation method is as follows:

[0110] (1) Preparation of composite nanoparticle dispersion

[0111] Peanut protein was dispersed in deionized water to obtain a 1% (w / v) peanut protein solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure adequate hydration.

[0112] Gum arabic was dispersed in deionized water to obtain a 1% (w / v) solution of gum arabic, which was stirred at room temperature for 2 h and at 4°C overnight to ensure adequate hydration.

[0113] Then, peanut protein and gum arabic were mixed at a mass ratio of 15:1 and stirred at room temperature for 1 hour. The mixed solution was adjusted to pH 10 with 6M NaOH solution, stirred at 70°C for 0.5 hour, cooled to room temperature, and then adjusted to pH 7 with HCL and stirred for 1 hour to obtain a protein-polysaccharide composite nanoparticle dispersion.

[0114] (2) Preparation of Pickering emulsion and powdered oil

[0115] Soybean oil was used as the emulsion oil phase, and the mass ratio of soybean oil to protein-polysaccharide composite nanoparticles was 1:5. The soybean oil and protein-polysaccharide composite nanoparticles dispersion were mixed and sheared at 12000 rpm for 4 minutes to obtain a crude emulsion.

[0116] The obtained crude emulsion was circulated and homogenized twice at 600 bar.

[0117] Use a spray dryer, set the inlet air temperature of the spray drying process to 140°C, the feed flow rate to 4mL / min, and the air flow rate to 400L / h, spray dry the liquid feed after high-pressure homogenization to obtain powdered oil.

[0118] Example 8

[0119] Powdered fat, the preparation method is as follows:

[0120] (1) Preparation of composite nanoparticle dispersion

[0121] Oat protein was dispersed in deionized water to obtain a 3% (w / v) oat protein solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0122] Pectin was dispersed in deionized water to obtain a 3% (w / v) pectin solution, which was stirred at room temperature for 2 h and at 4°C overnight to ensure full hydration.

[0123] Then, oat protein and pectin were mixed at a mass ratio of 8:1 and stirred at room temperature for 1 hour. The mixed solution was adjusted to pH 9 with 6M NaOH solution, stirred at 90°C for 1.5 hours, cooled to room temperature, and then adjusted to pH 7 with HCL, stirred for 1 hour to obtain a protein-polysaccharide composite nanoparticle dispersion.

[0124] (2) Preparation of Pickering emulsion and powdered oil

[0125] With camellia oil as the emulsion oil phase, camellia oil and protein-polysaccharide composite nanoparticle dispersion were mixed at a mass ratio of 3:1 and high-speed sheared at 15000 rpm for 8 minutes to obtain a crude emulsion.

[0126] The obtained crude emulsion was circulated and homogenized under high pressure at 800 bar for 4 times.

[0127] Use a spray dryer, set the inlet air temperature of the spray drying process to 170°C, the feed flow rate to 8mL / min, and the air flow rate to 800L / h, spray dry the liquid feed after high-pressure homogenization to obtain powdered oil.

[0128] Comparative Example 1

[0129] Powdered fat, the preparation method is as follows:

[0130] (1) Preparation of protein solution

[0131] The pea protein isolate (PPI) was dispersed in deionized water to obtain a 2% (w / v) pea protein isolate solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0132] The mixed solution was adjusted to pH 12 with 6M NaOH solution, stirred at 85°C for 1 h, cooled to room temperature, and then adjusted to pH 7 with HCL and stirred for 1 h to obtain a protein solution.

[0133] (2) Preparation of Pickering emulsion and powdered oil

[0134] Linseed oil was used as the emulsion oil phase, and the linseed oil and protein solution were mixed at a linseed oil to protein ratio of 1:1, and high-speed shearing was performed at 14000 rpm for 5 minutes to obtain a crude emulsion.

[0135] The obtained crude emulsion was subjected to a high pressure homogenization process at 700 bar for 3 cycles.

[0136] Use a spray dryer, set the inlet air temperature of the spray drying process to 150°C, the feed flow rate to 6mL / min, and the air flow rate to 600L / h, spray dry the liquid feed after high-pressure homogenization to obtain powdered oil.

[0137] Comparative Example 2

[0138] The method is basically the same as Example 3, except that the inlet air temperature of the spray drying is changed. The inlet air temperature of this comparative example is 180°C. The spray drying is specifically as follows:

[0139] With linseed oil as the emulsion oil phase, the mass ratio of linseed oil to protein-polysaccharide composite nanoparticles was 1:1, and the linseed oil and protein-polysaccharide composite nanoparticle dispersion was high-speed sheared at 14000 rpm for 5 minutes to obtain a crude emulsion. The obtained crude emulsion was circulated under 700 bar for 3 times.

[0140] Use a spray dryer, set the inlet air temperature of the spray drying process to 180°C, the feed flow rate to 6mL / min, and the air flow rate to 600L / h, spray dry the liquid feed after high-pressure homogenization to obtain powdered oil.

[0141] Comparative Example 3

[0142] The method is basically the same as Example 3, except that the pH value is controlled in the preparation of step (1). The specific steps of step (1) are as follows:

[0143] The pea protein isolate (PPI) was dispersed in deionized water to obtain a 2% (w / v) pea protein isolate solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0144] Propylene glycol alginate (PGA) was dispersed in deionized water to obtain a 2% (w / v) sodium alginate propylene glycol ester solution, which was stirred at room temperature for 2 h and kept at 4°C overnight to ensure full hydration. Then, PPI:PGA was mixed at a mass ratio of 10:1 and stirred at room temperature for 1 h.

[0145] The mixed solution was adjusted to pH 12 with 6 M NaOH solution, stirred at 85° C. for 1 h, and cooled to room temperature to obtain a protein-polysaccharide composite nanoparticle solution.

[0146] This comparative example adjusts the pH control process, and the protein-polysaccharide composite nanoparticles in the obtained protein-polysaccharide composite nanoparticle solution are larger and have a wider particle size distribution, and the powdered fat is larger and has a lower oil loading rate.

[0147] Comparative Example 4

[0148] The method is basically the same as Example 3, except that no heating is performed during the pH shift in the preparation of step (1). Step (1) is specifically as follows:

[0149] The pea protein isolate (PPI) was dispersed in deionized water to obtain a 2% (w / v) pea protein isolate solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0150] Propylene glycol alginate (PGA) was dispersed in deionized water to obtain a 2% (w / v) PGA solution, which was stirred at room temperature for 2 h and at 4° C. overnight to ensure sufficient hydration.

[0151] Then, the mixture was mixed at a mass ratio of PPI:PGA of 10:1 and stirred at room temperature for 1 hour. The mixed solution was adjusted to pH 12 with 6M NaOH solution, stirred at room temperature for 1 hour, and then adjusted to pH 7 with HCL and stirred for 1 hour to obtain a protein-polysaccharide composite particle solution.

[0152] In this comparative example, the pH was adjusted to 12 without heating and was directly stirred at room temperature. The particle size of the protein-polysaccharide composite nanoparticles in the obtained protein-polysaccharide composite nanoparticle solution was larger, and the particle size of the powdered oil was larger, which was more prone to oil leakage and agglomeration.

[0153] Test example:

[0154] 1. Particle size analysis

[0155] The particle size distribution of the PPI-PGA composite nanoparticles (A) and the emulsion (B) after high pressure homogenization in the embodiment and the comparative example, as well as the particle size of the powdered oil were measured using a nanometer particle size analyzer, a zeta potential analyzer and a particle size analyzer. The results are as follows: Figure 1 And as shown in Table 1.

[0156] in, Figure 1 The particle size distribution of the PPI-PGA composite nanoparticles (Figure A) and the emulsion after high pressure homogenization (Figure B) of Example and Comparative Example 1. The ratio in the figure represents the mass ratio of PPI to PGA. As can be seen from the figure, the PPI-PGA composite nanoparticles after pH shift (see Figure A) have a smaller particle size. The particle size of the composite nanoparticles gradually increases with the addition of PGA, and the polysaccharide is embedded in the system. Figure 1 As shown in Figure B, with the increase of PGA, the particle size of the emulsion after high-pressure homogenization first decreases and then increases. When the PPI:PGA ratio is 10:1, the emulsion particle size is the smallest. Figure 1 It can be seen that a certain ratio of protein to polysaccharide can reduce the particle size of the homogenized emulsion, and the reduction in the particle size ensures the reduction in the final powder oil particle size. The smaller the powder oil particle size, the lower the adhesion between the powder oils, the higher the stability of the powder oils, and the better the oil embedding effect.

[0157] The particle sizes of the powdered fats and oils prepared in the examples and comparative examples are shown in the following table:

[0158] Table 1 Particle size of powdered fats prepared in Examples and Comparative Examples

[0159] Examples Particle size (μm) Example 1 11.73±0.17 Example 2 11.15±0.18 Example 3 9.47±0.11 Example 4 10.85±0.43 Example 5 11.43±0.39 Example 6 9.53±0.11 Comparative Example 1 27.69±4.41

[0160] It can be seen from the above table that the particle size of the powdered oil stabilized by PPI-PGA composite nanoparticles is relatively small. With the increase of PGA, the particle size of the emulsion first decreases and then increases. When the PPI:PGA ratio is 10:1, the particle size of the powdered oil is the smallest.

[0161] Figure 2 The particle size distribution of the powdered fats prepared in Example 3 and Comparative Example 1. Figure A shows the powdered fat stabilized by plant protein nanoparticles in Comparative Example 1, and Figure B shows the powdered fat stabilized by protein-polysaccharide composite nanoparticles in Example 3. As shown in the figure, after the introduction of polysaccharides, the powder changes from bimodal to unimodal, the particle size distribution becomes narrower, and the particle size becomes smaller, indicating that the polysaccharides in the examples are successfully embedded in the system, the protein and polysaccharides form composite nanoparticles, and the size of the obtained powdered fat is more uniform.

[0162] (2) The oil loading, surface oil and water content of the powdered fats prepared in Example and Comparative Example 1 were measured. The results are shown in the following table.

[0163] in,

[0164] Oil loading (%) = weight of oil loaded by powdered oil / total weight of powdered oil × 100% (1) Surface oil (%) = surface oil weight of powdered grease / total weight of powdered grease × 100% (2)

[0165] Water content (%) = [1-(weight of powdered fat after drying / weight of powdered fat before drying)] × 100% (3) Encapsulation rate (%) = (loaded oil - surface oil) / loaded oil × 100% (4) Oil loading rate (%) = oil loading / theoretical oil loading × 100% (5) Table 2: Performance test of powdered fats prepared in Examples and Comparative Examples

[0166]

[0167] As can be seen from the table, the total oil content of the powdered fats prepared in the embodiments of the present invention is close to the theoretical value of 50%, indicating that although some oil is lost during the drying process, the powdered fats prepared by the method of the present invention have a higher oil loading rate. As the proportion of polysaccharides increases, the oil loading increases first and then decreases. When the PPI:PGA ratio is 10:1, the oil loading of the powdered fat is the highest, which is 49.03%. And when the PPI:PGA ratio is 10:1, the powdered fat has the lowest surface oil and moisture content, indicating that the powdered fat of the embodiment of the present invention has a high embedding rate, is more stable, and has a better drying effect.

[0168] Figure 3 The following are photos of powdered greases of Example 3 and Comparative Example 2 of the present invention. Figure A is a sample of powdered grease of Comparative Example 2; Figure B is a sample of powdered grease of Example 3. As shown in the figure, the powdered grease sprayed at 180°C is yellower in color and has obvious lumps, indicating that the inlet air temperature is too high. Figure B is whiter in color and has fewer lumps. The powdered grease sprayed at an inlet air temperature of 150°C is better than that at 180°C.

[0169] The present invention uses plant protein-polysaccharide composite nanoparticles as wall materials to prepare powdered grease with low surface oil content, and can load active substances such as curcumin to improve its bioaccessibility.

[0170] The present invention adopts a novel method for preparing plant protein-polysaccharide composite nanoparticles, and the pH shift is used to jointly treat the protein-polysaccharide mixed solution to simply prepare stable composite nanoparticles. The stable powder of plant protein-polysaccharide composite nanoparticles has a high oil loading rate and a low surface oil content.

[0171] The above is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A method for preparing a novel powdered oil stabilized by plant protein-polysaccharide composite nanoparticles, characterized in that: The preparation method comprises the following steps: S1: After the vegetable protein is dispersed in water, it is stirred overnight for hydration to obtain a vegetable protein dispersion; S2: After the polysaccharide is dispersed in water, it is stirred overnight for hydration to obtain a polysaccharide dispersion; S3: mixing the plant protein dispersion of S1 with the polysaccharide dispersion of S2 to obtain a mixed solution, adjusting the pH to alkaline, heating and stirring, cooling to room temperature, and then adjusting the pH to neutral to obtain a plant protein-polysaccharide composite nanoparticle dispersion; S4: Add the oil phase to the dispersion of plant protein-polysaccharide composite nanoparticles, shear emulsify to obtain a coarse emulsion, and then homogenize under high pressure to obtain a fine emulsion, spray dry the fine emulsion to obtain a powdered oil that is stable with plant protein-polysaccharide composite nanoparticles.

2. The preparation method according to claim 1, characterized in that: In S1, the plant protein includes one or more of pea protein, peanut protein, soy protein, chickpea protein, oat protein, quinoa protein, potato protein, zein, and wheat prolamin; The concentration of the vegetable protein dispersion is 1-5% (w / v).

3. The preparation method according to claim 1, characterized in that: In S2, the polysaccharide includes one or more of propylene glycol alginate, gum arabic, pectin, xanthan gum, konjac gum and sodium alginate; The concentration of the polysaccharide dispersion is 1-5% (w / v).

4. The preparation method according to claim 1, characterized in that: In S3, in the mixed solution, the mass ratio of the plant protein to the polysaccharide is 3-20:

1.

5. The preparation method according to claim 1, characterized in that: In S3, the pH is adjusted to alkaline by using alkaline solution to adjust the pH to 9-12.

6. The preparation method according to claim 1, characterized in that: The heating and stirring temperature is 70-90°C and the time is 0.5-1.5h; The pH adjustment to neutral refers to adjusting the pH to 7.0 with an acid solution.

7. The preparation method according to claim 1, characterized in that: In S4, the oil phase includes one or more of linseed oil, corn oil, soybean oil, peanut oil, rapeseed oil, olive oil, sesame oil, camellia oil, walnut oil, and fish oil; The mass ratio of the oil phase to the plant protein-polysaccharide composite nanoparticles is 1:5-3:

1.

8. The preparation method according to claim 1, characterized in that: In S4, the shear emulsification speed is 12000-15000 r / min, and the time is 4-8 min; the pressure of the high-pressure homogenization is 600-800 bar, and the number of cycles of the high-pressure homogenization is 2-4 times.

9. The preparation method according to claim 1, characterized in that: In S4, the inlet air temperature of the spray drying is 140-170°C, the feed flow rate is 4-8 mL / min, and the air flow rate is 400-800 L / h.

10. A novel plant protein-polysaccharide composite nanoparticle-stabilized powdered oil prepared by the preparation method according to any one of claims 1 to 9.

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