Diglyceride Pickering emulsion

Abstract

The invention provides a diglyceride Pickering emulsion and a preparation method thereof. The diglyceride Pickering emulsion contains lotus seed protein, diglyceride and water according to the mass ratio of (0.25-0.75): (70-85): (20-25), a specific fixing agent (lotus seed protein) is selected, the dosage ratio of the fixing agent to the diglyceride and other components is regulated and controlled, the fixing agent, the diglyceride and other components serve as a carrier of volatile substances, and the diglyceride Pickering emulsion can be used for preparing the volatile substances under the condition that triglyceride is not used; the slow-release effect on volatile substances is obviously improved, and the slow-release film also has relatively good stability and is suitable for being applied to foods containing volatile substances, such as baked products and meat products.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology. More specifically, it relates to a diglyceride Pickering emulsion. Background Technology

[0002] Volatile substances are key components of food aroma and flavor, and have a crucial impact on food quality and consumer acceptance. Due to their volatile nature, these substances impart unique aromas and flavors to food, thereby enhancing its overall quality. However, if these substances evaporate too quickly, the aroma and flavor of food can be rapidly lost during processing and storage, leading to a rapid decline in food quality.

[0003] To achieve the slow release of volatile substances, the food industry often uses triglycerides and other oils as carriers. Their unique physical and chemical properties, such as melting point and viscosity, are used to regulate the release rate of volatile substances, thereby extending the retention time of food aroma and flavor, and prolonging the shelf life. However, as a major component of fat, excessive long-term intake of triglycerides can lead to excessive fat accumulation and energy surplus in the body, subsequently causing health problems such as obesity and cardiovascular disease.

[0004] To avoid the health problems caused by excessive triglyceride intake, researchers have begun exploring the use of healthier fats such as diglycerides as alternatives. Diglycerides are fats with a unique structure and a different metabolic pathway than triglycerides, making them less likely to be stored as fat in the body, thus considered a healthier fat option. However, as a carrier, diglycerides have limited effectiveness in the sustained release of volatile substances. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a diglyceride Pickering emulsion. By selecting a specific fixative (lotus seed protein) and adjusting the ratio of the fixative to components such as diglyceride, it serves as a carrier for volatile substances. This not only significantly improves the sustained-release effect of volatile substances without the use of triglycerides, but also exhibits better stability, making it suitable for use in baked goods, meat products, and other foods containing volatile substances.

[0006] The first objective of this invention is to provide a diglyceride Pickering emulsion.

[0007] A second objective of this invention is to provide a method for preparing the above-mentioned diglyceride Pickering emulsion.

[0008] A third objective of this invention is to provide the application of the above-mentioned diglyceride Pickering emulsion in the slow-release of volatile substances.

[0009] A fourth objective of this invention is to provide a Pickering emulsion containing volatile substances.

[0010] The fifth objective of this invention is to provide a method for preparing the Pickering emulsion containing the above-mentioned volatile substances.

[0011] The sixth object of the present invention is to provide the application of the above-mentioned diglyceride Pickering emulsion or the above-mentioned Pickering emulsion containing volatile substances in the preparation of food.

[0012] The above-mentioned objective of this invention is achieved through the following technical solution: This invention provides a diglyceride Pickering emulsion containing lotus seed protein, diglyceride, and water in a mass ratio of 0.25–0.75:70–85:20–25.

[0013] Preferably, the mass ratio of lotus seed protein, diglyceride, and water is 0.5:78:22.

[0014] Based on this, the present invention also provides a method for preparing the above-mentioned diglyceride Pickering emulsion, specifically: mixing lotus seed protein, diglyceride, and water, and then homogenizing to obtain the emulsion.

[0015] Preferably, the rotational speed for homogenization is 16,000 to 20,000 rpm. Most preferably, it is 18,000 rpm.

[0016] Preferably, the homogenization time is 3 to 5 minutes. Most preferably, it is 3 minutes.

[0017] The lotus seed protein of the present invention can be extracted using conventional methods in the art, for example, a method including the following steps: S1. Add lotus seed extract to water and mix well, then adjust the pH to 11.5-12.5, extract for 11-13 h, and then separate the solid and liquid components. S2. Adjust the pH of the liquid obtained from the solid-liquid separation in S1 to 4.8–5.0, extract at 3–5 ℃ for 11–13 h, then separate the solid and liquid. The obtained solid is lotus seed protein.

[0018] As an optional implementation, the ratio of lotus seed extract to water in S1 is 0.8–1.2 g: 98–102 mL. The most preferred ratio is 1 g: 100 mL.

[0019] As an optional implementation, the pH in S1 is adjusted using sodium hydroxide.

[0020] As an optional implementation, the extraction temperature described in S1 is 20–30 °C.

[0021] As an optional implementation, the extraction in S1 is performed simultaneously with stirring, such as stirring at 180–220 rpm.

[0022] As an optional implementation, the solid-liquid separation described in S1 is achieved by centrifugation, such as centrifugation at 3500–4500 rpm for 6–10 min.

[0023] As an optional implementation, the pH in S2 is adjusted by hydrochloric acid.

[0024] As an optional implementation, the solid-liquid separation described in S2 is achieved by centrifugation, such as centrifugation at 3200–4000 rpm for 6–10 min.

[0025] As an optional implementation, after the solid-liquid separation described in S2, post-processing is performed, such as washing and drying in sequence.

[0026] Furthermore, the cleaning is performed with water until the system pH is neutral.

[0027] Furthermore, the drying is achieved by vacuum freeze drying.

[0028] The aforementioned diglyceride Pickering emulsion, by selecting a specific fixative (lotus seed protein) and adjusting the ratio of the fixative to components such as diglyceride, serves as a carrier for volatile substances. This significantly enhances the sustained-release effect of volatile substances without the use of triglycerides. Therefore, the application of the aforementioned diglyceride Pickering emulsion in the sustained release of volatile substances should also fall within the scope of protection of this invention.

[0029] Preferably, the volatile substance is one or more of 2,6-dimethylpyrazine, trans-2,4-decadienal, and 3-methylbenzaldehyde.

[0030] Based on this, the present invention also provides a Pickering emulsion containing volatile substances, which contains lotus seed protein, diglycerides, volatile substances, and water in a mass ratio of 0.25-0.75:70-85:0.006-0.01:20-25.

[0031] The preparation method of the above-mentioned Pickering emulsion containing volatile substances is also very simple: mix lotus seed protein, diglyceride, volatile substances and water, and then homogenize.

[0032] Preferably, the rotational speed for homogenization is 16,000 to 20,000 rpm. Most preferably, it is 18,000 rpm.

[0033] Preferably, the homogenization time is 3 to 5 minutes. Most preferably, it is 3 minutes.

[0034] The aforementioned diglyceride Pickering emulsion, by selecting a specific fixative (lotus seed protein) and adjusting the ratio of the fixative to components such as diglyceride, serves as a carrier for volatile substances. This not only significantly enhances the sustained-release effect of volatile substances without the use of triglycerides but also exhibits superior stability, making it suitable for use in baked goods, meat products, and other foods containing volatile substances. Therefore, this invention also provides the application of the aforementioned diglyceride Pickering emulsion or the aforementioned Pickering emulsion containing volatile substances in food preparation.

[0035] The present invention has the following beneficial effects: The diglyceride Pickering emulsion of the present invention, by selecting a specific fixative (lotus seed protein) and adjusting the ratio of the fixative to components such as diglyceride, serves as a carrier for volatile substances. It not only significantly improves the sustained-release effect of volatile substances without the use of triglycerides, but also has better stability, making it suitable for use in baked goods, meat products, and other foods containing volatile substances. Detailed Implementation

[0036] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0037] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0038] Lotus seed protein: 1 g of lotus seed extract (purchased from Shaanxi Shengtai Biotechnology Co., Ltd.) was added to 100 mL of water and mixed well to form a uniform suspension. The pH was then adjusted to 12 with 0.5 mol / L sodium hydroxide solution, and extracted by stirring continuously at 25 ℃ and 200 rpm for 12 h. After centrifugation at 4000 rpm for 8 min, the pH of the supernatant obtained by centrifugation was adjusted to 4.9 with 0.5 mol / L hydrochloric acid solution, and extracted at 4 ℃ for 12 h. After centrifugation at 3600 rpm for 8 min, the precipitate obtained by centrifugation was washed with water until the pH of the system was neutral, and finally freeze-dried under vacuum to obtain the final product.

[0039] Diglycerides: Purchased from Guangdong Yueshan Special Medical Nutrition Technology Co., Ltd.

[0040] 2,6-Dimethylpyrazine: purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0041] Triglycerides: Purchased from Guangdong Yueshan Special Medical Nutrition Technology Co., Ltd.

[0042] Whey protein isolate: purchased from Shanghai Maclean Biotechnology Co., Ltd.

[0043] Soy protein isolate: purchased from Shanghai Maclean Biotechnology Co., Ltd.

[0044] Example 1: Preparation of Diglyceride Pickering Emulsion Mix lotus seed protein, diglyceride, and water in a mass ratio of 0.5:78:22, and then homogenize at 18000 rpm for 3 minutes to obtain the final product.

[0045] Example 2: Preparation of Diglyceride Pickering Emulsion Mix lotus seed protein, diglyceride, and water in a mass ratio of 0.75:85:20, and then homogenize at 16000 rpm for 5 min to obtain the final product.

[0046] Example 3: Preparation of Diglyceride Pickering Emulsion Mix lotus seed protein, diglyceride, and water in a mass ratio of 0.25:70:25, and then homogenize at 20,000 rpm for 3 minutes to obtain the final product.

[0047] Example 4: Preparation of Pickering emulsion containing volatile substances Mix lotus seed protein, diglyceride, 2,6-dimethylpyrazine, and water in a mass ratio of 0.5:78:0.008:22, and then homogenize at 18,000 rpm for 3 min to obtain the final product.

[0048] Example 5: Preparation of Pickering emulsion containing volatile substances Mix lotus seed protein, diglyceride, 2,6-dimethylpyrazine, and water in a mass ratio of 0.75:85:0.006:20, and then homogenize at 16,000 rpm for 5 min to obtain the final product.

[0049] Example 6: Preparation of Pickering emulsion containing volatile substances Mix lotus seed protein, diglyceride, 2,6-dimethylpyrazine, and water in a mass ratio of 0.25:70:0.01:25, and then homogenize at 20,000 rpm for 3 min to obtain the final product.

[0050] Comparative Example 1 Same as Example 1, except that diglycerides are replaced with triglycerides.

[0051] Comparative Example 2 Same as Example 1, except that lotus seed protein is replaced with whey protein isolate.

[0052] Comparative Example 3 Same as Example 1, except that lotus seed protein is replaced with soy protein isolate.

[0053] Comparative Example 4 Same as Example 1, except that the mass ratio of lotus seed protein, diglyceride, and water is 1:70:22.

[0054] Comparative Example 5 Same as Example 4, except that lotus seed protein is replaced with soy protein isolate.

[0055] Comparative Example 6 Same as Example 4, except that the mass ratio of lotus seed protein, diglyceride, 2,6-dimethylpyrazine, and water is 1:70:0.008:22.

[0056] Test Example 1: Stability Test of Diglyceride Pickering Emulsion Take 40 mL of the Pickering emulsions obtained in Examples 1-3 and Comparative Examples 1-4, and place them in 50 mL centrifuge tubes respectively. Let them stand at room temperature (25 ℃) for 8 h, and observe the layering at 0, 2, 4, 6, and 8 h. The emulsification index (CI) of the Pickering emulsion is calculated according to "CI = volume of supernatant / total volume of Pickering emulsion × 100%". The results are shown in Table 1.

[0057] Table 1

[0058] In Table 1, " / " indicates no obvious stratification.

[0059] It can be seen that the Pickering emulsions obtained in Examples 1-3 and Comparative Examples 3-4 can still maintain good stability after standing for 8 hours, while the Pickering emulsions obtained in Comparative Examples 1-2 showed obvious stratification at 2 hours and 4 hours, respectively.

[0060] Test Example 2: The sustained-release effect of diglyceride Pickering emulsion on volatile substances. In this test, the flavor retention rate of volatile substances in Examples 4-6 and Comparative Examples 5-6 was used as an indicator to characterize the sustained-release effect of Pickering emulsions obtained in Examples 1-3 and Comparative Examples 3-4 on volatile substances.

[0061] I. Determination of 2,6-dimethylpyrazine content The content of volatile substances (2,6-dimethylpyrazine) in the sample was determined by gas chromatography-mass spectrometry.

[0062] The chromatographic conditions were as follows: Agilent 19091S-431UI (HP-5ms Ultra Inert) column (1 m × 250 μm × 0.25 μm), injection port temperature 250 ℃, detection port temperature 280 ℃, pressure 45.6 kPa, total flow rate 50 mL / min, split ratio 3:1, PAL injector, helium (99.99%) as carrier gas at a flow rate of 2.25 mL / min. The temperature program was: hold at 60 ℃ for 1 min, then increase to 250 ℃ at a rate of 10 ℃ / min and hold for 5 min.

[0063] Mass spectrometry conditions: EI ionization mode, interface temperature 300 ℃, ion source temperature 250 ℃, collision gas nitrogen, flow rate 1.5 mL / min, full scan mode for data acquisition, scan range m / z 40~450.

[0064] II. Standard Curve of 2,6-Dimethylpyrazine 2,6-Dimethylpyrazine was dissolved in water to obtain 2,6-dimethylpyrazine solutions with concentrations of 20, 40, 60, 80, and 100 μg / mL. The peak area of ​​2,6-dimethylpyrazine was detected by gas chromatography-mass spectrometry, and a standard curve of 2,6-dimethylpyrazine was plotted with concentration as the abscissa and peak area as the ordinate.

[0065] III. Test Method for the Sustained Release Effect of Diglyceride Pickering Emulsion on Volatile Substances Take 1 g of the Pickering emulsion containing volatile substances obtained in Examples 4-6 and Comparative Examples 5-6, and place them in 20 mL screw headspace vials. Let them stand for 8 h. At 0, 2, 4, 6, and 8 h, the content of 2,6-dimethylpyrazine in the sample is determined by gas chromatography-mass spectrometry and the standard curve of 2,6-dimethylpyrazine. The retention rate of 2,6-dimethylpyrazine in the sample at the test time is calculated according to "flavor retention rate (%) = (initial content - test content) / initial content × 100%". This characterizes the sustained-release effect of the Pickering emulsions obtained in Examples 1-3 and Comparative Examples 3-4 on volatile substances.

[0066] IV. Test Results of the Sustained-Release Effect of Diglyceride Pickering Emulsion on Volatile Substances The results are shown in Table 2.

[0067] Table 2

[0068] In Table 2, the superscript letters indicate significant differences between individual columns of data.

[0069] As can be seen, with the extension of time, the flavor retention rate of the Pickering emulsions containing volatile substances obtained in Examples 4-6 and Comparative Examples 5-6 all showed a decreasing trend. Obviously, the flavor retention rate of the Pickering emulsions containing volatile substances obtained in Comparative Examples 5-6 decreased faster, indicating that the diglyceride Pickering emulsion of the present invention, by selecting a specific fixative (lotus seed protein) and controlling the ratio of the fixative to components such as diglyceride, can better delay the release of volatile substances as a carrier.

[0070] 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 diglyceride Pickering emulsion, characterized in that, It contains lotus seed protein, diglycerides, and water in a mass ratio of 0.25–0.75:70–85:20–25.

2. The diglyceride Pickering emulsion according to claim 1, characterized in that, The mass ratio of lotus seed protein, diglyceride, and water is 0.5:78:

22.

3. The method for preparing the diglyceride Pickering emulsion according to any one of claims 1 to 2, characterized in that, The lotus seed protein, diglyceride, and water are mixed and homogenized to obtain the final product.

4. The preparation method according to claim 3, characterized in that, The rotational speed of the homogenizer is 16,000 to 20,000 rpm.

5. The preparation method according to claim 3, characterized in that, The homogenization time is 3 to 5 minutes.

6. The use of the diglyceride Pickering emulsion according to any one of claims 1 to 2 in the slow-release volatile substances.

7. The application according to claim 6, characterized in that, The volatile substance is one or more of 2,6-dimethylpyrazine, trans-2,4-decadienal, and 3-methylbenzaldehyde.

8. A Pickering emulsion containing volatile substances, characterized in that, It contains lotus seed protein, diglycerides, volatile substances, and water in a mass ratio of 0.25–0.75:70–85:0.006–0.01:20–25.

9. The method for preparing the Pickering emulsion containing volatile substances as described in claim 8, characterized in that, The lotus seed protein, diglyceride, volatile substances, and water are mixed and homogenized to obtain the final product.

10. The use of the diglyceride Pickering emulsion of any one of claims 1 to 2 or the Pickering emulsion containing volatile substances of claim 8 in the preparation of food.

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