Chinese prickly ash seed oil emulsion for low-fat food as well as preparation method and application of Chinese prickly ash seed oil emulsion

Abstract

The invention relates to a Chinese prickly ash seed oil emulsion for low-fat food and a preparation method and application thereof, and the preparation method comprises the following steps: 1) ethanol extraction of Chinese prickly ash seed oil: drying Chinese prickly ash seeds until the moisture content is below 10%, crushing, sieving, degreasing and drying; taking absolute ethyl alcohol as a solvent, performing constant-temperature extraction and filtration to obtain a mixed solution of crude Chinese prickly ash seed oil and ethyl alcohol, and performing rotary evaporation to remove ethyl alcohol to obtain Chinese prickly ash seed oil; 2) preparation of a chickpea protein solution: preparing a 10 mg / mL chickpea protein solution by using deionized water, and stirring to obtain the chickpea protein solution; 3) ultrasonic emulsification: mixing the Chinese prickly ash seed oil with the chickpea protein solution; an ultrasonic probe is immersed in a position 1.5 cm away from the upper surface of the emulsion for ultrasonic treatment, ice-water bath temperature control is performed in the whole emulsification process, protein denaturation caused by local overheating is avoided, and the treated product is stored at 4 DEG C; according to the preparation method, the emulsification efficiency is remarkably improved, the emulsification time is shortened to 15 min through the ultrasonic cavitation effect, and particle size distribution is uniform.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of food technology, and in particular to a Zanthoxylum bungeanum seed oil emulsion for low-fat food, a preparation method and application thereof. BACKGROUND

[0002] With the increasing demand for the development of functional oil and plant protein composite system in the food industry, emulsification technology has become the key to achieving stable dispersion of oil and improving bioavailability. Currently, ultrasonic emulsification is the mainstream of high-efficiency emulsification. Ultrasonic emulsification technology generates shear force through cavitation effect, which can quickly break up oil phase particles.

[0003] Non-meat proteins as emulsifiers for stable pre-emulsified oils can enhance the strength of protein matrices and improve product quality during production. Chickpea protein solution, as a plant protein emulsifier, has good emulsification properties and stability. As a high-quality plant protein source, the emulsification performance of chickpea protein is significantly affected by concentration and preparation process. Traditional emulsification processes (such as high-speed shearing) are difficult to balance particle size control and stability, while ultrasonic enhanced emulsification effect, but process parameters need to be optimized to balance efficiency and cost.

[0004] Zanthoxylum bungeanum seeds are the main by-products of Zanthoxylum bungeanum seasoning, accounting for about 60% of the whole Zanthoxylum bungeanum. A large amount of them are discarded and not fully utilized, causing resource waste and environmental pollution. Given the high oil content of Zanthoxylum bungeanum seeds, they are gradually being developed for the production of edible oil in order to alleviate the above problems. Zanthoxylum bungeanum seed oil is a natural oil rich in unsaturated fatty acids (such as alpha-linolenic acid) and bioactive ingredients (such as zanthoxylum oil), which has important application value in the fields of food, medicine and cosmetics. However, its high unsaturation characteristics are prone to oxidation and deterioration, and it needs to be converted into oil-in-water (O / W) emulsion through emulsification technology to improve its stability and bioavailability.

[0005] The extraction methods of Zanthoxylum bungeanum seed oil include pressing, solvent extraction (such as anhydrous ethanol extraction), supercritical CO2 extraction and aqueous enzymatic extraction. Among them, the ethanol extraction method is the mainstream process due to its simple operation and low solvent residue, but the traditional process has problems such as high extraction temperature (such as 59 ℃) and long extraction time (2.7 h).

[0006] (1) Ethanol extraction combined with mechanical emulsification method Currently, in the prior art, Zanthoxylum bungeanum seed oil is extracted by anhydrous ethanol extraction (solid-liquid ratio 1:5, 59 ℃), and then emulsified by mechanical stirring method, the oil phase ratio is usually less than 30%, and the emulsion stability depends on chemical emulsifiers (such as Tween 80), which limits the control of interfacial activity. Mechanical stirring method needs a long time (> 30 min) and the emulsion particle size distribution is uneven (> 2000 nm), which leads to poor storage stability, and additional chemical emulsifiers (such as Tween 80) need to be added, affecting the naturalness of the product.

[0007] (2) Ultrasonic-assisted Pickering emulsion technology Pickering emulsion relies on complex additives, such as solid nanoparticles (e.g., zein-pectin composite), which requires a complicated preparation process and high cost. Moreover, the interface properties are not optimized by ultrasonic parameters (e.g., 450 W, 15 min), resulting in limited emulsification efficiency.

[0008] Zein-pectin composite nanoparticles are used to stabilize emulsions, and ultrasonic-assisted dispersion (power 200-600 W, time 10-20 min) is used to optimize the solid particle concentration to 35 g / L. However, the influence of oil phase ratio on the interfacial potential and microstructure has not been systematically studied.

[0009] (3) Supercritical CO2 extraction combined with microfluidic emulsification Supercritical CO2 extraction of Zanthoxylum bungeanum seed oil (yield 12.7%) combined with microfluidic technology to prepare core-shell microcapsules, but the process is complex, the equipment cost is high, and the emulsion loading efficiency is not optimized for high oil phase ratio (e.g., 50%).

[0010] (4) Ionic liquid ultrasonic emulsification microextraction technology In the field of cosmetic detection, ionic liquid-ultrasonic emulsification method (power 300-500 W, time 5-10 min) is used to achieve micron-level dispersion, but it does not involve natural proteins (e.g., chickpea protein) as emulsifiers, and the oil phase ratio adjustment range is limited.

[0011] In summary, traditional mechanical stirring or high-speed shearing methods have the disadvantages of high energy consumption, large emulsion particle size, and excessive dispersion coefficient, which can easily separate into layers. Pickering emulsion relies on solid particle stabilizers (e.g., zein-pectin composite), which requires complex process control and is relatively expensive. In addition, existing research focuses on low oil phase ratio (<40%) systems, and the synergistic effects of high oil phase ratio (50%) on emulsification activity, Zeta potential, and microstructure have not been systematically evaluated, resulting in low emulsion loading efficiency. Moreover, existing ultrasonic emulsification techniques mostly use synthetic emulsifiers or ionic liquids, and do not fully utilize the interfacial stability of natural proteins (e.g., chickpea protein), resulting in insufficient biocompatibility of the emulsion. Ultrasonic emulsification method achieves micron-level dispersion through cavitation effect, but existing research mostly focuses on single parameter optimization (e.g., power or time), and lacks the synergistic effect of oil phase ratio and ultrasonic parameters. SUMMARY

[0012] To address the problems of traditional mechanical stirring or high-speed shearing methods, which require long processing times, result in large emulsion particle sizes leading to high energy consumption and poor stability, rely on complex additives (such as solid particles or chemical emulsifiers), lack systematic research on emulsifying activity, zeta potential, and microstructure at high oil ratios (e.g., 50%), and the insufficient biocompatibility of emulsions due to the lack of full utilization of the interfacial stabilizing effect of natural proteins (such as chickpea protein) in existing ultrasonic emulsification technology, the present invention aims to provide a Sichuan pepper seed oil emulsion for low-fat foods, its preparation method, and its application.

[0013] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a Sichuan pepper seed oil emulsion for use in low-fat foods includes the following steps: (1) Ethanol extraction of Sichuan pepper seed oil Raw material pretreatment: After drying the peppercorns to a moisture content of less than 10%, they are crushed, sieved, degreased, and then dried. Extraction: Using anhydrous ethanol as solvent, the mixture was extracted at a constant temperature. After filtration, a mixed solution of crude pepper seed oil and ethanol was obtained. The ethanol was removed by rotary evaporation to obtain pepper seed oil. (2) Preparation of chickpea protein solution Prepare a 10 mg / mL chickpea protein solution using deionized water by stirring. (3) Ultrasonic emulsification Oil-water mixture: Mix Sichuan pepper seed oil with chickpea protein solution; Ultrasound: The ultrasonic probe is immersed 1.5 cm from the surface of the emulsion for ultrasonic treatment. The temperature is controlled by an ice water bath throughout the emulsification process to avoid local overheating that could lead to protein denaturation. The treated product is stored at 4°C.

[0014] Furthermore, in step (1), the drying temperature of the pepper seeds is 75℃ and the time is 4 h; the drying temperature after defatting is 60℃ and the time is 4 h.

[0015] Furthermore, in step (1), the ratio of material to liquid for extraction is 1g:3mL; the extraction temperature is 60℃ and the extraction time is 50min.

[0016] Furthermore, in step (1), the rotary evaporation temperature is 46°C and the speed is 55 r / min. The rotation speed and temperature can be adjusted according to the ethanol distillation situation.

[0017] Furthermore, in step (2), magnetic stirring is used at a temperature of 25°C for 2 hours.

[0018] Furthermore, in step (3), the oil content is 50%.

[0019] Furthermore, in step (3), the ultrasonic emulsification operating parameters are 20 kHz, 450 W, and 15 min.

[0020] Furthermore, in step (3), the ultrasonic emulsification working mode is 2 seconds of operation followed by 4 seconds of intermittent operation.

[0021] The pepper seed oil emulsion obtained by this invention can be used to prepare low-fat foods.

[0022] Compared with the prior art, the beneficial effects of the present invention are: (1) The preparation method of the present invention significantly improves the emulsification efficiency: the ultrasonic cavitation effect shortens the emulsification time to 15 min (the traditional method requires more than 30 min), and the particle size distribution is uniform (PDI < 0.2).

[0023] (2) The preparation method of the present invention avoids dependence on chemical additives: chickpea protein forms a stable film layer through interfacial adsorption (CLSM confirms the continuous protein encapsulation structure), with an absolute value of Zeta potential > 30 mV, and no need to add stable particles.

[0024] (3) The preparation method of the present invention reduces the preparation cost: the ethanol extraction method and ultrasonic emulsification method are used. Compared with the traditional method, the equipment cost is reduced and the energy consumption is reduced, which is suitable for large-scale production.

[0025] (4) The preparation method of the present invention optimizes the emulsion formulation: by systematically studying the effect of different oil ratios on the emulsion performance, the optimal oil ratio was determined to be 50%, thus optimizing the emulsion formulation and improving the performance and stability of the emulsion. Attached Figure Description

[0026] Figure 1 This is a process flow diagram for preparing Sichuan pepper seed oil emulsion.

[0027] Figure 2 The effect of different oil phase volume fractions on the emulsifying activity and stability of the emulsion.

[0028] Figure 3 The effect of different oil phase volume fractions on emulsion potential.

[0029] Figure 4 The effect of different oil phase volume fractions on emulsion particle size distribution.

[0030] Figure 5 The effect of different oil phase volume fractions on the microstructure of the emulsion.

[0031] Figure 6 The effect of different oil phase volume fractions on the appearance of the emulsion.

[0032] Figure 7 This is a laser confocal image of the emulsion. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] like Figure 1 As shown, a method for preparing a Sichuan pepper seed oil emulsion for low-fat foods includes the following steps: 1. Preparation of oil and aqueous phases (1) Ethanol extraction method for Sichuan pepper seed oil: Raw material pretreatment: Sichuan pepper seeds are dried (75℃, 4 h) until the moisture content is below 10%, then crushed and passed through a 60-mesh sieve, defatted and dried (60℃, 4 h).

[0035] Extraction process: The material-to-liquid ratio is 1:3 (g / mL). Anhydrous ethanol is used as the solvent. The extraction is carried out at a constant temperature (60 ℃, 50 min). The crude pepper seed oil and ethanol mixture is obtained by filtration. The ethanol is removed by rotary evaporation (46 ℃, 55 r / min, the speed and temperature are adjusted according to the ethanol evaporation) to obtain pepper seed oil.

[0036] (2) Preparation of chickpea protein solution: Prepare a 10 mg / mL chickpea protein solution using deionized water and stir magnetically (25℃, 2h).

[0037] 2. Ultrasonic emulsification process (ultrasonic-assisted high-pressure microjet method) (1) Oil-water mixture: Sichuan pepper seed oil and chickpea protein solution were mixed according to the oil ratio (10%, 20%, 30%, 40%, 50%, 60%), with a total system volume of 50 mL.

[0038] (2) Ultrasound parameters: The ultrasonic probe was immersed 1.5 cm from the surface of the emulsion for ultrasonic treatment (20 kHz, 450 W, 15 min), with a working mode of 2 seconds on, followed by a 4-second interval. The treated sample was stored at 4°C.

[0039] (3) Temperature control measures: The entire emulsification process is controlled by an ice-water bath to prevent localized overheating that could lead to protein denaturation.

[0040] The properties of the prepared Sichuan pepper seed oil emulsion were characterized as follows: (1) Emulsifying activity and stability: Immediately sample the prepared emulsion, fixing the sampling point 0.5 cm from the bottom of the beaker. Take 10 μL of the emulsion and mix it evenly with 10 mL of 0.1% (w / v) SDS solution. Measure its absorbance (A0) at 500 nm. After the emulsion has stood for 10 min, measure its absorbance (A0) again using the same method. 10 A blank control was prepared using 0.1% SDS. The emulsifying activity (EAI) and emulsifying stability (ESI) were calculated according to the formulas: ; ; In the formula: T = 2.303; N represents the dilution factor, 1000; C represents the protein concentration in the protein aqueous solution before emulsion formation, g·mL; The value in the figure represents the volume fraction of oil in the emulsion.

[0041] (2) Zeta potential and particle size distribution: The potential value of the protein emulsion was measured using a Zetasizer Nano Zs90 laser particle size analyzer. The measurement temperature was set to 25 ℃, and three parallel measurements were performed. The average value was taken.

[0042] The emulsion was diluted 1000 times with deionized water, sonicated for 30 min, and then slowly added to a quartz cuvette. The particle size was then analyzed by a Malvern laser particle size analyzer.

[0043] (3) Microstructure analysis: Take 10 μL of emulsion and drop it into the center of a glass slide. Gently touch the edge of the drop with one side of a coverslip and slowly cover it to prevent air bubbles from forming. Observe the distribution of the droplet in the emulsion under an optical microscope.

[0044] (4) Appearance of the emulsion: The emulsion was placed in a 10 ml glass bottle and left to stand at room temperature for 28 days. The appearance of the emulsion was photographed at 0 days and 28 days.

[0045] (5) Laser confocal scanning image: CPI-Sichuan pepper seed oil emulsion was observed using a laser confocal scanning microscope. 40 μL of a 0.1% Nile blue and Nile red mixture was added to 1 mL of the emulsion, and the mixture was vortexed to stain the emulsion. 10 μL of the stained emulsion was then dropped onto a glass slide, and the emulsion was observed under a 40x microscope with excitation wavelengths of 488 and 633 nm.

[0046] (6) Determination of the optimal oil phase volume fraction: The effects of different oil phase volume fractions on the emulsifying activity and stability of the emulsion are as follows: Figure 2As shown, the effect of different oil phase volume fractions on emulsion potential is as follows: Figure 3 As shown in the figure, the effect of different oil phase volume fractions on emulsion particle size distribution is as follows: Figure 4 As shown, the effects of different oil phase volume fractions on the microstructure of the emulsion are as follows: Figure 5 As shown, the effect of different oil phase volume fractions on the appearance of the emulsion is as follows: Figure 6 As shown, the laser confocal image results of the emulsion are as follows: Figure 7 As shown.

[0047] Based on a comprehensive analysis of EAI, ESI, Zeta potential (absolute value > 30 mV), particle size distribution, microstructure, emulsion appearance, and laser confocal images, a 50% oil-to-emulsion ratio was selected as the optimal parameter.

[0048] In summary, this invention achieves a synergistic design of the oil and aqueous phases: ethanol extraction preserves the active components of Sichuan pepper seed oil, while chickpea protein provides natural interfacial stabilization. Furthermore, the ultrasonic parameters were optimized to match the oil content: a combination of 450 W power, 15 min ultrasonic time, and a 50% oil content yielded a highly stable nanoemulsion. The product's microstructure is controllable: the integrity of the protein interfacial adsorption layer was verified using CLSM, ensuring the long-term stability of the emulsion.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A process for the preparation of Zanthoxylum bungeanum seed oil emulsion for low fat food characterized in that, Comprising the following steps: (1) Zanthoxylum bungeanum seed oil ethanol extraction Raw material pretreatment: Zanthoxylum bungeanum seed is dried to a moisture content of less than 10%, then crushed and sieved, defatted and dried; Extraction: using anhydrous ethanol as the solvent, constant temperature extraction, filtration to obtain a crude Zanthoxylum bungeanum seed oil and ethanol mixed solution, rotary evaporation to remove ethanol, and Zanthoxylum bungeanum seed oil is obtained; (2) Chickpea protein solution preparation Prepare a 10 mg / mL chickpea protein solution using deionized water, and stir to obtain; (3) Ultrasonic emulsification Oil and water mixing: mix Zanthoxylum bungeanum seed oil and chickpea protein solution; Ultrasonic: immerse the ultrasonic probe into the emulsion solution 1.5 cm above the surface for ultrasonic treatment, and control the temperature with an ice water bath throughout the emulsification process to avoid local overheating causing protein denaturation. The product is stored at 4°C after treatment.

2. The method of preparing Zanthoxylum seed oil emulsion according to claim 1, characterized by: In step (1), the Zanthoxylum bungeanum seed is dried at a temperature of 75°C for 4 h; and after defatting and drying, the temperature is 60°C for 4 h.

3. The method of preparing Zanthoxylum seed oil emulsion according to claim 2, characterized by: In step (1), the solid-liquid ratio for extraction is 1g:3mL; the extraction temperature is 60°C for 50 min.

4. The method for preparing the Sichuan pepper seed oil emulsion according to claim 3, characterized in that: In step (1), the rotary evaporation temperature is 46°C, and the speed is 55 r / min, which can be adjusted according to the ethanol evaporation conditions.

5. The method for preparing the Sichuan pepper seed oil emulsion according to claim 4, characterized in that: In step (2), magnetic stirring is used at a temperature of 25°C for 2 h.

6. The method of preparing Zanthoxylum bungeanum seed oil emulsion according to claim 5, characterized in that: In step (3), the oil phase ratio is 10-60%.

7. The method for preparing the Sichuan pepper seed oil emulsion according to claim 6, characterized in that: In step (3), the ultrasonic emulsification working parameters are 20 kHz, 450 W, and 15 min.

8. The method for preparing the Sichuan pepper seed oil emulsion according to claim 7, characterized in that: In step (3), the ultrasonic emulsification working mode is 2s working and 4s intermittent.

9. Zanthoxylum bungeanum seed oil emulsion prepared by the preparation method of any one of claims 1-8.

10. Use of the Zanthoxylum bungeanum seed oil emulsion of claim 9 in the preparation of low-fat food.

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