Preparation method of lotus root whole powder-based high internal phase emulsion

Abstract

The invention provides a preparation method of a lotus root whole powder-based high internal phase emulsion, and relates to the technical field of emulsion preparation. The lotus root whole powder based high internal phase emulsion is prepared by compounding gelatinized lotus root whole powder suspension and whey protein suspension in a water bath, then mixing with soybean oil according to an oil-water ratio of 4: 1, and then shearing and homogenizing. According to the preparation method, the defects in the prior art are overcome, the high-internal-phase Pickering emulsion can be prepared, the oil content of the emulsion can reach 85%, and the emulsion has higher stability.

Description

Technical Field

[0001] The invention relates to the technical field of emulsion preparation, and in particular to a method for preparing a lotus root whole-powder-based high internal phase emulsion. Background Art

[0002] High internal phase emulsions (HIPEs), with internal phase volume fractions exceeding 74.05%, have shown significant application potential in food texture design, active ingredient encapsulation, and fat replacement. However, conventional HIPE preparation relies heavily on synthetic surfactants or polymer stabilizers, posing potential health risks and environmental burdens. Pickering emulsions, based on particle stabilization mechanisms, have become a research hotspot in recent years due to their high stability, low toxicity, and environmental friendliness. Starch-based granules are particularly attractive due to their widespread availability, renewable nature, and biodegradability. Currently, research on starch-based Pickering emulsions has primarily focused on the modification of single starches, such as corn and potato. While physical or chemical modification can enhance starch's hydrophobicity and interfacial adsorption capacity, the complex modification processes and the potential introduction of chemical residues limit their potential for food applications. Furthermore, the interfacial stabilization efficiency of single starch granules is limited, making it difficult to form a stable structure under high internal phase conditions. Therefore, developing natural, unmodified, multicomponent starch-based granules to enhance emulsion performance through synergistic interactions between components has become an important approach to overcome current technological bottlenecks.

[0003] Whole lotus root flour (whole lotus root starch) is made from lotus roots through a simple process involving washing and drying. It retains all nutritional components, including protein and dietary fiber, and offers the advantages of low water consumption and high resource efficiency. However, its composition is complex, its particles are irregular in morphology, and its hydrophilicity is relatively strong, making its solubility and hydration capacity weaker than those of traditional lotus root starch. Currently, the interfacial behavior, structure-activity relationship, and stabilization mechanism of whole lotus root flour as a natural Pickering stabilizer in high internal phase emulsions remain unclear, and its potential for green preparation and functional applications is urgently needed. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a method for preparing a lotus root whole powder-based high internal phase emulsion, which can be used to prepare a high internal phase Pickering emulsion, and the emulsion can reach an oil content of 85% and has higher stability.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for preparing a lotus root whole-powder-based high internal phase emulsion, comprising the following steps: S1. Prepare a 5%-8% w / v lotus root powder suspension and a whey protein suspension for later use; S2, gelatinizing the lotus root powder suspension to obtain a gelatinized lotus root powder material for later use; S3, mixing the gelatinized lotus root powder and the whey protein suspension, and then compounding them in a water bath to obtain a composite solution for standby use; S4. The composite liquid is mixed with soybean oil at an oil-water ratio of 4:1, and then sheared and homogenized to obtain a lotus root whole powder-based high internal phase emulsion.

[0006] Preferably, the lotus root powder in step S1 is prepared from fresh lotus root (lotus root) which is washed and sliced, dried with hot air at 65° C. for 12 h, ground in a high-speed universal grinder for 2-4 minutes, and passed through a 100-mesh sieve to obtain the powder.

[0007] Preferably, the gelatinization temperature in step S2 is 90° C., and the gelatinization time is 20 min.

[0008] Preferably, in step S3, the gelatinized lotus root powder is completely cooled to room temperature before being mixed with the whey protein suspension.

[0009] Preferably, in step S3, the volume ratio of the gelatinized lotus root powder and the whey protein suspension is 10:1.

[0010] Preferably, the temperature of the water bath compounding in step S3 is 45-55° C., and the compounding time is 1 hour.

[0011] Preferably, the shear homogenization speed in step S4 is 12000 r / min and the time is 2 min.

[0012] The present invention provides a method for preparing a lotus root whole-powder-based high internal phase emulsion, which has the following advantages over the prior art: (1) The present invention is green and environmentally friendly. No chemical modification reagents are required throughout the process. The natural dietary fiber, polyphenols and whey protein in the lotus root powder are used synergistically to give the emulsion antioxidant activity and nutritional enhancement function. It can replace hydrogenated oil or solid fat, meets the requirements of clean label and green processing, and is suitable for the fields of healthy food, cosmetics and pharmaceutical carriers.

[0013] (2) The present invention has the characteristics of efficient interfacial adsorption and high oil phase stability. The starch structure is destroyed by pre-gelatinizing the whole lotus root powder to release amylopectin, and then compounded with whey protein to significantly improve the hydrophobicity and interfacial activity of the composite particles. Combined with high-speed shear homogenization to construct a three-dimensional network structure, the long-term stability and high thermal stability of the emulsion with an oil content of 85% are achieved.

[0014] (3) The present invention overcomes the defects of strong hydrophilicity of lotus root powder and insufficient interfacial stability of a single component through a step-by-step compounding process (pre-gelatinization-protein compounding) and an efficient shear homogenization strategy. The process flow is simple and adaptable to high-temperature food processing (such as baking and sterilization) and industrial continuous production requirements, providing a reliable technical path for the large-scale preparation of high internal phase emulsions based on natural components. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 1 and 30 days after the appearance of lotus root powder-based high internal phase emulsions with different oil-water ratios in the examples of the present invention; Figure 2 Graph showing the average particle size of lotus root powder-based high internal phase emulsions with different oil-water ratios at 1 day and 30 days in the examples of the present invention; Figure 3 Schematic diagram of optical microscopy of lotus root whole powder-based high internal phase emulsions with different oil-water ratios at 1 day and 30 days in an embodiment of the present invention; Figure 4 2 are the zeta potential diagrams of lotus root powder-based high internal phase emulsions with different oil-water ratios at 1 day and 30 days in the examples of the present invention; Figure 5 CLSM images of lotus root powder-based high internal phase emulsions with different oil-water ratios in the examples of the present invention. DETAILED DESCRIPTION

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0016] In the following examples, the lotus root powder is prepared from fresh lotus root (Lotus lily) which is washed and sliced, dried with hot air at 65° C. for 12 h, ground in a high-speed universal grinder for 2-4 minutes, and passed through a 100-mesh sieve.

[0017] Example: Preparation of lotus root powder-based high internal phase emulsion: (1) A 6% lotus root powder suspension and a whey protein suspension were prepared according to the w / v ratio. The lotus root powder suspension was gelatinized in a 90°C water bath for 20 min, and then rapidly cooled to room temperature to obtain gelatinized lotus root powder. (2) The gelatinized lotus root powder and whey protein suspension were mixed at a ratio of 10:1 (v / v) and compounded in a 50°C water bath for 1 h to obtain the compound solution for later use; (3) The above composite liquid was added with soybean oil according to the oil-water ratio of 1:2, 1:1, 2:1, 4:1, and 6:1, and sheared and homogenized at 12000 r / min for 2 min to obtain lotus root whole powder-based high internal phase emulsions with different oil-water ratios.

[0018] Detection: 1. Detection of the static stratification of lotus root powder-based high internal phase emulsions with different oil-water ratios: The prepared emulsion samples were placed at room temperature for 1 day, and then photographed with a digital camera. After 30 days of standing, the samples were photographed again to observe the stratification of each group of emulsions. Specific results such as Figure 1 As shown, the emulsions with oil-water ratios of 1:2, 1:1, and 6:1 showed obvious stratification after 30 days of standing, while the emulsions with oil-water ratios of 2:1 and 4:1 showed no obvious stratification after 30 days of standing.

[0019] 2. Particle size determination: Mastersizer 3000 equipment was used to determine the average particle size of emulsions with different oil-water ratios at 1 day and 30 days after preparation. The specific results are as follows: Figure 2 As shown in the figure, the emulsions were stable for 30 days at oil-water ratios of 4:1 and 2:1, and the particle size did not change much; 3. Microscopic examination: The microstructure of each emulsion at 1 day and 30 days after preparation was observed using an optical microscope. A 10 μL droplet of the emulsion was deposited onto a microscope slide, which was then covered with a cover glass. The sample was observed at a magnification of 10 × 2. See Figure 3 As shown, the microstructure of emulsion 30d with an oil-water ratio of 4:1 changes little.

[0020] 4. Zeta potential detection: A Zetasizer Nano ZS90 instrument was used to measure the zeta potential of the emulsion samples. To mitigate the occurrence of multiple scattering, the zeta potential of the sample was evaluated by diluting the emulsion with ultrapure water at a ratio of 1:100 after preparation. Specific results such as Figure 4 As shown in the figure, the absolute value of the zeta potential of the lotus root powder-based emulsion exceeds 40 mV when the oil-water ratio is 4:1, indicating that its interfacial particles produce strong electrostatic repulsion due to the high surface charge, and the synergistic three-dimensional network structure gives the emulsion excellent long-term stability.

[0021] 5. Confocal laser scanning microscopy (CLSM) detection: LSM880 high-resolution laser confocal microscopy (CLSM) was used to observe the microstructure of the emulsion; Nile red in anhydrous ethanol (30 μL, 0.1 wt%), rhodamine B in water (30 μL, 0.1 wt%), and Nile blue in water (30 μL, 0.1 wt%) were added to an emulsion (1 mL) and stored at room temperature in the dark. Before preparing each emulsion, soybean oil was labeled with Nile red, whey protein with rhodamine B, and lotus root powder with Nile blue A. After preparation, a small amount was dropped onto a glass slide and a coverslip was pressed firmly against it. To prevent evaporation of the emulsion and dye extinction, a thin layer of nail polish was applied around the coverslip to seal it and the slide was wrapped with tin foil. Gels were then prepared according to the above method and observed under laser confocal microscopy at excitation wavelengths of 488 nm, 546 nm, and 633 nm.

[0022] Specific results can be found in Figure 5 As can be seen from the figure, the CLSM image clearly shows that the lotus root whole powder-whey protein complex forms a dense interface layer (O / W type) at an oil-water ratio of 4:1, and the oil droplets are wrapped inside the water phase droplets (W / O / W double emulsion structure), which significantly improves the stability; while at an oil-water ratio of 6:1, the interface particles are sparsely adsorbed, resulting in large oil droplet aggregation and demulsification. In the range of 1:2-4:1, the droplet gap shrinks and the network density increases, verifying the structure-activity relationship between interface particle distribution and emulsion stability.

[0023] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a lotus root whole powder-based high internal phase emulsion, characterized in that: The preparation method comprises the following steps: S1. Prepare a 5%-8% w / v lotus root powder suspension and a whey protein suspension for later use; S2, gelatinizing the lotus root powder suspension to obtain a gelatinized lotus root powder material for later use; S3, mixing the gelatinized lotus root powder and the whey protein suspension, and then compounding them in a water bath to obtain a composite solution for standby use; S4. The composite liquid is mixed with soybean oil at an oil-water ratio of 4:1, and then sheared and homogenized to obtain a lotus root whole powder-based high internal phase emulsion.

2. The preparation method according to claim 1, wherein: The lotus root powder in step S1 is prepared by washing and slicing fresh lotus roots, drying them with hot air at 65° C. for 12 hours, grinding them in a high-speed universal grinder for 2-4 minutes, and passing them through a 100-mesh sieve to obtain the powder.

3. The preparation method according to claim 1, wherein: The gelatinization temperature in step S2 is 90° C., and the gelatinization time is 20 min.

4. The preparation method according to claim 1, wherein: In step S3, the gelatinized lotus root powder is completely cooled to room temperature and then mixed with the whey protein suspension.

5. The preparation method according to claim 1, wherein: In step S3, the volume ratio of the gelatinized lotus root powder and the whey protein suspension is 10:

1.

6. The preparation method according to claim 1, wherein: The temperature of the water bath compounding in step S3 is 45-55° C., and the compounding time is 1 hour.

7. The preparation method according to claim 1, wherein: The shearing and homogenizing process in step S4 was performed at a speed of 12000 r / min and for a time of 2 min.

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