Pickering high internal phase emulsion-carrot juice compound beverage and preparation process thereof

Abstract

The invention discloses a Pickering high internal phase emulsion-carrot juice compound beverage and a preparation technology thereof, and relates to the technical field of food processing. The formula of the compound beverage comprises Pickering high internal phase emulsion, carrot juice, white granulated sugar, white granulated sugar and xanthan gum. The preparation method comprises the following steps: S1, preparing a whey protein isolate-Arabic gum nano-composite; s2, preparing a Pickering high internal phase emulsion; s3, preparing carrot juice; s4, the carrot juice is slowly added into the Pickering high internal phase emulsion, the mixture is stirred to be uniform, xanthan gum, white granulated sugar and citric acid are added for blending, the Pickering high internal phase emulsion-carrot juice compound beverage is obtained, the addition amount of the emulsion accounts for 5%-15% of the total mass of the compound beverage, the addition amount of the xanthan gum accounts for 0.01%-0.05% of the total mass of the compound beverage, and the addition amount of the carrot juice accounts for 0.01%-0.05% of the total mass of the compound beverage. The addition amount of the white granulated sugar is 4%-8% of the total mass of the compound beverage, and the addition amount of the citric acid is 0.04%-0.08% of the total mass of the compound beverage. The invention provides a preparation process of a stable Pickering high internal phase emulsion-carrot juice compound beverage based on whey protein isolate and Arabic gum.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, and particularly relates to a Pickering high internal phase emulsion-carrot juice compound beverage and a preparation process thereof. Background Art

[0002] With the increasing demand of consumers for healthy foods, the functional beverage market has developed rapidly. Carrot juice has become a popular functional drink because it is rich in nutrients such as carotenoids, vitamins and minerals. Carotenoids are the precursor substances of vitamin A, which are widely present in plants, fungi and algae, and have the functions of protecting eyesight and reducing the risk of cancer and chronic diseases. However, the carotenoids in carrot juice are extremely unstable during processing, transportation and metabolism, and will degrade under various physical and chemical actions, resulting in low bioavailability of carotenoids and restricting the full play of its nutritional value. Therefore, it is very necessary to improve the bioavailability of carotenoids in carrot juice.

[0003] Carotenoids need to form mixed micelles with bile salts and dietary fats in the intestine to be absorbed, and the absorption efficiency can be significantly improved by combining with oils. In order to improve the stability of oils in fruit juices, emulsion technology has been widely used in the development of functional beverages. When the volume fraction of the dispersed phase is greater than 74.05%, it can be called a high internal phase emulsion, and its rheological properties show a solid-like plastic behavior. Such a structure has unique application values in fields such as the food industry (such as low-fat sauces) and drug sustained-release carriers. The traditional high internal phase emulsion system has long relied on small molecule surfactants to achieve stability. However, such emulsifiers show low adsorption ability at the oil-water interface. To maintain the stability of the system, usually a very high addition amount is required, and there is even a risk of biosafety, which seriously restricts its application in the food and pharmaceutical fields. In recent years, Pickering emulsions have become a research hotspot because they use solid particles (such as proteins, polysaccharides, etc.) as stabilizers, and have the advantages of non-toxicity, environmental protection and high stability.

[0004] Therefore, to solve the above technical problems, a new technical solution is needed, especially a Pickering high internal phase emulsion-carrot juice compound beverage and a preparation process thereof. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of insufficient stability of traditional emulsions and low bioavailability of fat-soluble nutrients (carotenoids) in carrot juice, and provides a Pickering high internal phase emulsion-carrot juice compound beverage and a preparation process thereof.

[0006] To achieve the above object, the present invention provides the following technical solution: A Pickering high internal phase emulsion - carrot juice compound beverage, comprising Pickering high internal phase emulsion, carrot juice, granulated sugar, citric acid and xanthan gum. The proportion of the Pickering high internal phase emulsion is: 5 - 15% (w / w); the proportion of the carrot juice is: 76.87 - 90.95% (w / w); the proportion of the granulated sugar is: 4 - 8% (w / w); the proportion of the citric acid is: 0.04 - 0.08% (w / w); the proportion of the xanthan gum is: 0.01 - 0.05% (w / w);

[0007] The Pickering high internal phase emulsion comprises edible oil, whey protein isolate, gum arabic and water. The proportion of the edible oil is: 75% (v / v); the proportion of the whey protein isolate is: 1 - 3% (w / v); the proportion of the gum arabic is: 1 - 3% (w / v); the remaining component is water.

[0008] Preferably, the edible oil is one or a mixture of safflower oil, walnut oil, linseed oil, grape seed oil, perilla oil, olive oil.

[0009] Preferably, the proportion of the Pickering high internal phase emulsion is 10% (w / w), the proportion of the carrot juice is 81.89% (w / w), the proportion of the granulated sugar is 8% (w / w), the proportion of the citric acid is 0.08% (w / w), and the proportion of the xanthan gum is 0.03% (w / w);

[0010] The proportion of the edible oil in the Pickering high internal phase emulsion is 75% (v / v), the proportion of the whey protein isolate is 1% (w / v), the proportion of the gum arabic is 2% (w / v), and the remaining components are water.

[0011] The present invention also provides a preparation process of a Pickering high internal phase emulsion - carrot juice compound beverage, comprising the following steps:

[0012] S1: Prepare a whey protein isolate - gum arabic nanocomposite

[0013] Dissolve whey protein isolate and gum arabic at room temperature, pH = 10.0 ± 0.5, with stirring for 3 - 4 h until completely dissolved, adjust the pH to 7.0 ± 0.5, and stir for 1 - 2 h; the added mass ratio of whey protein isolate to gum arabic is 3:1 - 1:3, to obtain a whey protein isolate - gum arabic nanocomposite with a solids content of 3%.

[0014] Since whey protein isolate can dissolve in a highly alkaline environment, but its solubility will decrease after being adjusted back to a neutral environment, combined with its self-assembly behavior, whey protein isolate-gum arabic composite nanoparticles are formed. Therefore, the experimental pH is adjusted.

[0015] S2: Preparation of Pickering high internal phase emulsion

[0016] One or a mixture of safflower oil, walnut oil, and linseed oil is slowly added to the whey protein isolate-gum arabic nano-composite emulsion, and shear homogenization is carried out at a rotation speed of 14,000 rpm. The volume fraction of the oil phase is 75%, and a Pickering high internal phase emulsion is obtained.

[0017] S3: Preparation of carrot juice

[0018] Carrots are washed, boiled in water, and then pulped with pure water, and the carrot juice is obtained by filtration.

[0019] S4: The carrot juice is slowly added to the Pickering high internal phase emulsion, stirred evenly, and xanthan gum, granulated sugar, and citric acid are added for formulation to obtain a Pickering high internal phase emulsion-carrot juice compound beverage. The addition amount of the emulsion is 5%-15% of the total mass of the compound beverage, the addition amount of xanthan gum is 0.01%-0.05% of the total mass of the compound beverage, the addition amount of the granulated sugar is 4%-8% of the total mass of the compound beverage, and the addition amount of the citric acid is 0.04%-0.08% of the total mass of the compound beverage.

[0020] Preferably, in step S1, the added mass ratio of whey protein isolate to gum arabic is 1:2.

[0021] Preferably, in step S3, the boiling in water before the preparation of carrot juice is boiling water for 4 min, and the mass ratio of the carrot to pure water during pulping is 1:1.

[0022] Preferably, in step S4, the addition amount of the emulsion is 10% of the total mass of the compound beverage.

[0023] Preferably, in step S4, the addition amount of xanthan gum is 0.03% of the total mass of the compound beverage.

[0024] Preferably, in step S4, the addition amount of the granulated sugar is 8% of the total mass of the compound beverage.

[0025] Preferably, in step S4, the addition amount of the citric acid is 0.06% of the total mass of the compound beverage.

[0026] The beneficial effects of the present invention are as follows:

[0027] (1) The present invention selects one or more vegetable oils rich in a large amount of unsaturated fatty acids from all edible oils such as safflower oil, walnut oil, linseed oil, grape seed oil, sea buckthorn oil, pumpkin seed oil, perilla oil, olive oil, etc., and prepares an oil-in-water Pickering high internal phase emulsion therefrom, which broadens the application scope of oils and solves the problem that traditional oils are insoluble in water. When compounded with carrot juice, the bioavailability of carotenoids is significantly improved, increasing from 57.12% to 79.20%, and the nutritional value of carrot juice is enhanced.

[0028] (2) The whey protein-arabic gum nanocomposite obtained in step S1 of the present invention has an average particle size between 214.52 - 336.14 nm. The whey protein and arabic gum are complexed through electrostatic interaction, having excellent emulsifying activity and emulsifying stability, and is an excellent Pickering emulsion stabilizer.

[0029] (3) The Pickering high internal phase emulsion obtained in step S2 of the present invention has an average emulsion particle size of 5.41 - 15.78 μm, has a relatively large viscosity and certain gel properties, has good salt ion stability, has good stability under the conditions of 4°C - 25°C, and the oxidative stability of the oil is significantly improved.

[0030] (4) The carrot juice compound beverage prepared in step S4 of the present invention has a uniform and natural color, no oil droplets floating, a mellow and delicate taste, and is sweet and sour. Compared with traditional carrot juice, the bioavailability of carotenoids is significantly improved, the absorption rate of carotenoids is significantly increased, and the nutritional value is significantly enhanced. Description of the Drawings

[0031] Figure 1 is a schematic structural diagram of the specific operation process of the present invention.

[0032] Figure 2 is an external view of the compound beverage prepared by the present invention (A: freshly prepared, B: after standing, C: shaken well before drinking).

[0033] Figure 3 is the average particle size and polydispersity index (PDI) of the whey protein-arabic gum nanocomposite (WPI-GA composite) with different ratios of the present invention.

[0034] Figure 4 is the zeta potential of WPI:GA nanoparticles with different ratios of the present invention.

[0035] Figure 5 is the SEM image of WPI:GA nanoparticles with different ratios of the present invention.

[0036] Figure 6These are the EAI and ESI diagrams of WPI:GA nanoparticles with different ratios of the present invention.

[0037] Figure 7 These are the FTIR infrared spectra diagrams of WPI:GA nanoparticles with different ratios of the present invention.

[0038] Figure 8 These are the secondary structure diagrams of WPI:GA nanoparticles with different ratios of the present invention.

[0039] Figure 9 These are the optical microscope and confocal laser scanning microscopy (CLSM) images of emulsions with different WPI:GA ratios of the present invention.

[0040] Figure 10 These are the particle size diagrams of emulsions with different WPI:GA ratios of the present invention.

[0041] Figure 11 These are the diagrams of the apparent viscosity changes of emulsions with different WPI:GA ratios of the present invention.

[0042] Figure 12 These are the diagrams of the changes in storage modulus (G') and loss modulus (G'') of emulsions with different WPI:GA ratios of the present invention.

[0043] Figure 13 These are the diagrams of the influence of different factors of the present invention on the sensory scores of the products. Detailed implementation manners

[0044] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following specific embodiments are used to describe the detailed implementation manners of the present invention in detail.

[0045] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0046] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that can be included in at least one implementation manner of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that excludes other embodiments.

[0047] I. Compound beverage and its preparation method

[0048] The present invention provides a Pickering high internal phase emulsion - carrot juice compound beverage, which includes Pickering high internal phase emulsion, carrot juice, granulated sugar, citric acid and xanthan gum. The proportion of the Pickering high internal phase emulsion is 10% (w / w), the proportion of carrot juice is 81.89% (w / w), the proportion of granulated sugar is 8% (w / w), the proportion of citric acid is 0.08% (w / w), and the proportion of xanthan gum is 0.03% (w / w); in the Pickering high internal phase emulsion, the proportion of edible oil is 75% (v / v), the proportion of whey protein isolate is 1% (w / v), the proportion of gum arabic is 2% (w / v), and the remaining component is water. The edible oil is one or more of all edible oils such as safflower oil, walnut oil, linseed oil, grape seed oil, sea buckthorn oil, pumpkin seed oil, perilla oil, olive oil, etc.

[0049] The preparation method is as follows:

[0050] Example 1: As Figure 1 shown, a preparation process of a Pickering high internal phase emulsion - carrot juice compound beverage includes the following steps:

[0051] S1. Stir the whey protein isolate and gum arabic at room temperature and pH = 10.0 for 3 h until completely dissolved, adjust the pH to 7.0, and stir for 1 h. The added mass ratio of the whey protein isolate to gum arabic is 1:2 to obtain a whey protein isolate - gum arabic nanocomposite with a solids content of 3%.

[0052] S2. Slowly add safflower oil to the whey protein isolate - gum arabic nanocomposite emulsion, and shear and homogenize at a rotation speed of 14000 rpm. The volume fraction of the edible oil is 75% to obtain a Pickering high internal phase emulsion.

[0053] The oil in the present invention is selected as vegetable oils rich in unsaturated fatty acids such as safflower oil, walnut oil, pumpkin seed oil, linseed oil, and sea buckthorn fruit oil. In this example, safflower oil is preferably used.

[0054] S3. Wash and cut the carrots, put them into boiling purified water, boil vigorously for 4 min, drain the water and take them out, then beat them with purified water. The mass ratio of the carrots to the purified water is 1:1, and use a filter screen to filter out the residues to obtain carrot juice.

[0055] S4. Slowly add carrot juice to the Pickering high internal phase emulsion, stir evenly, and add xanthan gum, granulated sugar, and citric acid for formulation to obtain a Pickering high internal phase emulsion-carrot juice compound beverage. The addition amount of the emulsion is 10% of the total mass of the compound beverage, the addition amount of xanthan gum is 0.03% of the total mass of the compound beverage, the addition amount of granulated sugar is 8% of the total mass of the compound beverage, and the addition amount of citric acid is 0.06% of the total mass of the compound beverage. The obtained product is as Figure 2 shown.

[0056] In the above steps, except for the steps involving the process product and the subsequent product having a sequential order, there is no mandatory sequential order among the remaining steps.

[0057] Example 2: A preparation process of a Pickering high internal phase emulsion-carrot juice compound beverage, comprising the following steps:

[0058] S1. Dissolve whey protein isolate and gum arabic at room temperature and pH = 10.0 by stirring for 3 h until completely dissolved, adjust the pH to 7.0, and stir for 1 h. The added mass ratio of whey protein isolate to gum arabic is 1:2 to obtain a whey protein isolate-gum arabic nanocomposite with a solids content of 3%.

[0059] S2. Slowly add safflower oil to the whey protein isolate-gum arabic nanocomposite emulsion, and shear and homogenize at a rotation speed of 14000 rpm. The volume fraction of the edible oil is 75% to obtain a Pickering high internal phase emulsion.

[0060] S3. Wash and cut carrots, put them into boiling purified water, boil vigorously for 4 min, drain the water and take them out, and make a pulp together with the purified water. The mass ratio of carrots to purified water is 1:1, and use a filter screen to filter out the residue to obtain carrot juice.

[0061] S4. Slowly add carrot juice to the Pickering high internal phase emulsion, stir evenly, and add xanthan gum, granulated sugar, and citric acid for formulation to obtain a Pickering high internal phase emulsion-carrot juice compound beverage. The addition amount of the emulsion is 10% of the total mass of the compound beverage, the addition amount of xanthan gum is 0.03% of the total mass of the compound beverage, the addition amount of granulated sugar is 6% of the total mass of the compound beverage, and the addition amount of citric acid is 0.8% of the total mass of the compound beverage.

[0062] Example 3: A preparation process of a Pickering high internal phase emulsion-carrot juice compound beverage, comprising the following steps:

[0063] S1. Dissolve whey protein isolate and gum arabic at room temperature with pH = 10.0 by stirring for 3 h until completely dissolved, adjust the pH to 7.0, and stir for 1 h. The added mass ratio of the whey protein isolate to the gum arabic is 1:2 to obtain a whey protein isolate - gum arabic nano - composite with a solids content of 3%.

[0064] S2. Slowly add safflower seed oil to the whey protein isolate - gum arabic nano - composite emulsion and shear - homogenize it at a rotational speed of 14000 rpm. The volume fraction of the edible oil is 75% to obtain a Pickering high - internal - phase emulsion.

[0065] S3. Wash and cut carrots, put them into boiling pure water, boil vigorously for 4 min, drain the water and take them out, then beat them into a pulp together with the pure water. The mass ratio of the carrots to the pure water is 1:1. Use a filter screen to filter out the residue to obtain carrot juice.

[0066] S4. Slowly add the carrot juice to the Pickering high - internal - phase emulsion, stir evenly, and add xanthan gum, granulated sugar, and citric acid for formulation to obtain a Pickering high - internal - phase emulsion - carrot juice compound beverage. The addition amount of the emulsion is 15% of the total mass of the compound beverage, the addition amount of xanthan gum is 0.05% of the total mass of the compound beverage, the addition amount of granulated sugar is 8% of the total mass of the compound beverage, and the addition amount of citric acid is 0.08% of the total mass of the compound beverage.

[0067] II. Basic properties of different - proportion whey protein isolate - gum arabic composites and their emulsions

[0068] On the basis of Example 1, a comparative experiment was carried out on the addition ratio in step S1 of Example 1. Change the composite ratio of whey protein isolate (WPI) and gum arabic (GA) to prepare safflower seed oil Pickering high - internal - phase emulsions. The added mass ratios of whey protein isolate to gum arabic are: 3:1, 2:1, 1:1, 1:2, 1:3. Measure the particle size, zeta potential, protein secondary structure, emulsifying properties of the nano - composites; the particle size, microstructure, rheological properties, thermal stability, and salt - ion stability of the emulsions, etc., to determine the optimal added mass ratio.

[0069] 1. Particle size and zeta potential of whey protein isolate - gum arabic composites with different ratios

[0070] Use a Zetasizer Nano ZS nano - particle size and zeta potential analyzer to measure its particle size and polydispersity index (PDI), and use a zeta potential analyzer to measure the zeta potential of the composite. The results are as Figure 3 、 Figure 4 shown. As Figure 3As shown, the average particle size of WPI without GA addition was the largest (336.14 ± 5.45 nm). As the proportion of GA increased, the average particle size of the WPI-GA complex gradually decreased. When WPI:GA = 1:2, the particle size of the complex was the smallest, at 214.52 ± 7.65 nm. WPI and GA formed a soluble intramolecular complex through electrostatic interaction. Then, when the GA addition continued to increase, the average particle size at WPI:GA = 3:1 increased significantly (p < 0.05). The reason may be that the steric hindrance of macromolecules resulted in fewer binding sites between polysaccharides and proteins, and the excess GA was coated on the surface of WPI, leading to a loose WPI-GA structure and adhesion between particles, thus increasing the particle size. As the GA addition increased, the WPI-GA nanoparticle solution showed a trend of first decreasing and then increasing. When WPI:GA = 1:2, the PDI value of the complex was the smallest, indicating that the WPI-GA composite nanoparticle solution prepared under this condition had better homogeneity and a more stable system. The decrease in the PDI value of the solution indicates a decrease in its aggregation degree, which may be because the electrostatic repulsion between WPI and GA molecules is enhanced. An excessive GA proportion caused the excess GA to be coated on the surface of WPI-GA, increasing the solution viscosity and causing adhesion between particles, resulting in poor solution homogeneity and an increase in the PDI value. As Figure 4 shown, the absolute value of the potential of pure WPI was the smallest, and the absolute value of the potential of all WPI-GA complexes increased with the increase in GA concentration. This phenomenon may be due to the addition of GA increasing the negative charge on the surface of the complex, thereby enhancing the electrostatic repulsion between ions. The higher the absolute value of the zeta potential, the more stable the WPI-GA nanoparticle solution. As the GA proportion increased, the absolute value of the potential of the complex gradually increased, and the stability of its solution was enhanced. Combining the analysis results of the average particle size of the complex, when WPI:GA = 1:2, the absolute value of the zeta potential of the solution was relatively large (62.52 ± 7.45 mV), and the particle size was relatively small (214.52 ± 7.65 nm), indicating better stability.

[0071] 2. SEM images of complexes with different ratios

[0072] As Figure 5 shown, Figure 5Shows the scanning electron microscope images of WPI and WPI-GA at a magnification of 1000 times. It can be seen from the figure that the surface structures of individual WPI and WPI-GA complexes are different. The scanning electron microscope of individual WPI shows that its surface is regular spherical. With the increase of the GA ratio, when WPI:GA = 3:1 and WPI:GA = 2:1, the regular spherical shape on the surface of the WPI-GA complex gradually becomes disordered. When WPI:GA = 1:1 and WPI:GA = 1:2, it is observed that the surface of the complex gradually becomes regular and flat; this indicates that with the increase of the GA ratio, more GA combines with WPI, affecting the composite structure of the WPI-GA complex. And with the continuous increase of the GA content, compared with WPI:GA = 1:2, the surface of the complex in the image of WPI:GA = 1:3 is no longer flat. At this time, the surface of the image is different from the spherical shape of the protein surface, which may be due to the excessive GA attaching and aggregating on the surface of the WPI-GA complex. Different ratios of WPI and GA will significantly affect the surface structure of the complex. Among the surface images of the WPI-GA complexes with different ratios observed, the WPI-GA complex with WPI:GA = 1:2 is superior to other samples.

[0073] 3. Emulsifying properties of complexes with different ratios

[0074] As Figure 6 shown, with the increase of the GA ratio, the emulsifying activity of the WPI-GA complex shows a trend of first increasing and then decreasing. This may be because the addition of the anionic polysaccharide GA breaks the aggregation between WPI particles, resulting in more hydrophobic groups being exposed and enhancing the binding ability with oil droplets. With the increase of the GA ratio, when the ratio of WPI:GA is 1:2, the emulsifying activity index (EAI) of the WPI-GA complex reaches the maximum value (37.34 m 2 / g), while when the ratio of WPI:GA is 1:3, the EAI of the complex decreases significantly (p < 0.05). The emulsifying stability index (ESI) of the WPI-GA complex increases with the increase of the GA content, while when the ratio of WPI to GA changes from 1:2 to 1:3, the change of the ESI value of the complex is not significant (p > 0.05). This may be because when an excessive amount of polysaccharide is added, the high viscosity of the polysaccharide will cause an increase in the solution viscosity. When GA is excessive, the polysaccharide molecules are prone to aggregation, thus forming larger aggregates, resulting in an increase in the particle size of the complex. The adsorption ability of these aggregates at the oil-water interface is weak and cannot effectively reduce the interfacial tension, thus affecting the emulsifying effect.

[0075] 4. Fourier transform infrared spectroscopy and protein secondary structure of complexes with different ratios

[0076] Figure 7The infrared spectra of WPI, GA, and the WPI-GA complex are shown. The main spectral features of WPI are the stretching vibrations of O-H and N-H at 3296.78 cm-1 in the amide A band, the stretching vibration of C=O at 1651.16 cm-1 in the amide I band, the bending vibration of N-H at 1540.51 cm-1 in the amide II band, the stretching vibration of C-N at 1240.65 cm-1 in the amide III band, and the stretching vibration of C-O at 1074.67 cm-1. The main spectral features of GA are the stretching vibrations of O-H and N-H at 3346.75 cm-1 in the amide A band, the stretching vibration of C=O at 1613.68 cm-1 in the amide I band, the stretching vibration of C-N at 1228.16 cm-1 in the amide III band, and the stretching vibration of C-O at 1040.79 cm-1. Compared with WPI (3296.78 cm-1), the peak position of WPI-GA shows a red shift, indicating the formation of a hydrogen bond between WPI and GA. Compared with WPI, the amide I band and amide II band of the WPI-GA complex also show a red shift, indicating that the addition of GA causes a change in the conformation of the amide bond and the formation of intramolecular hydrogen bonds.

[0077] Figure 8 Provides relevant information on the various secondary structures of WPI and the WPI-GA complex. With the increase in the content of GA, the proportions of α-helix and β-sheet decrease significantly (p<0.05), while the proportions of β-turn and random coil increase. These results indicate that the addition of GA changes the secondary structure of WPI. The addition of GA leads to the unfolding of the protein structure, and this change is highly correlated with the addition amount of GA. However, when the content of GA is too high and the ratio of WPI to GA changes from 1:2 to 1:3, the change in the protein secondary structure is not significant. This is consistent with the results of the emulsifying properties of WPI-GA analyzed previously. An appropriate ratio of WPI to GA (1:2) can change the secondary structure of the protein, significantly increase the proportions of β-turn and random coil, and significantly improve the emulsifying properties of the WPI-GA complex.

[0078] 5. Microstructure and particle size of Pickering high internal phase emulsions prepared with complexes of different ratios

[0079] As Figure 9As shown, images of Pickering high internal phase emulsions were taken under an optical microscope and a confocal laser scanning microscope (CLSM). Under the optical microscope, the structure of the droplets of the Pickering high internal phase emulsion could be seen, and the droplets were closely arranged. In the CLSM images, WPI-GA and edible oil were stained green and red, respectively, and the stained WPI-GA wrapped the red oil droplets. It can be seen that as the proportion of GA increased, the distribution of the emulsion droplets gradually became more uniform. When the ratio of WPI:GA was 1:2, the droplet size was the smallest and the distribution was the most uniform. When the ratio of WPI:GA reached 1:3, the emulsion droplets increased and the distribution of droplet sizes was uneven.

[0080] Figure 10 The average particle size of Pickering high internal phase emulsions prepared with WPI-GA nanoparticle solutions at different ratios is shown. It can be more intuitively shown that as the proportion of GA gradually increased, the average particle size of the emulsion droplets decreased from 15.78 ± 1.15 μm to 5.41 ± 0.69 μm when the ratio of WPI:GA was 1:2. The reason for the decrease in particle size may be that GA can reduce the interfacial tension of the Pickering high internal phase emulsion and form an electric double layer on the droplet surface, thereby inhibiting droplet aggregation and maintaining uniformity. When the ratio of WPI to GA was 1:3, the average particle size of the emulsion increased, which was consistent with the observation results of the microstructure of the emulsion droplets.

[0081] 6. Rheological properties of Pickering high internal phase emulsions prepared with different ratios of the composite

[0082] Figure 11 The figure shows the change in the apparent viscosity of the emulsion at different shear rates for different WPI:GA ratios. As shown in the figure, as the shear rate increased, the apparent viscosity of the Pickering high internal phase emulsion decreased, showing obvious shear thinning behavior. Under the action of shear force, the aggregated fat globules in the Pickering high internal phase emulsion system were broken, the resistance to the directional arrangement of the droplets decreased, and the viscosity decreased. The apparent viscosity of the Pickering high internal phase emulsion increased with the increase in the proportion of GA in the composite. When the ratio of WPI-GA was 1:2, the apparent viscosity of the emulsion reached the maximum value. When the proportion of GA further increased, the viscosity no longer increased. According to Stokes' law, when the viscosity of the system increases, the floating rate of the droplets in the emulsion will decrease, which helps the emulsion maintain higher stability. This again shows that the presence of polysaccharides improves the stability of the Pickering high internal phase emulsion. The presence of an appropriate proportion of polysaccharides can significantly increase the viscosity of the emulsion and play a key bridging role at the oil-water interface, effectively enhancing the stability of the interface.

[0083] As Figure 12As shown, within the entire frequency range, the G' of Pickering high internal phase emulsions is always greater than the corresponding G", indicating that the degree of reversible deformation of Pickering high internal phase emulsions is greater than that of irreversible deformation, and they possess certain gel properties. The dependence of both moduli on frequency is weak, which is a typical characteristic of the elastic structure formed by a highly dense particle layer. Compared with WPI, the G' and G" of the prepared Pickering high internal phase emulsions with WPI-GA are significantly increased. When the ratio of WPI-GA is 1:2, the modulus of the emulsion reaches the maximum value. The added GA adsorbs at the oil-water interface and wraps the oil droplets, thereby increasing the G' and G" values of the emulsion, which helps to improve its stability. When the ratio of WPI-GA is 1:2, the droplet size of the Pickering high internal phase emulsion is smaller, and smaller droplets may lead to closer packing and less fluidity, thus having a higher modulus and stronger anti-deformation ability. All in all, when the ratio of WPI-GA is 1:2, the prepared Pickering high internal phase emulsion has more excellent rheological properties.

[0084] From the above experimental studies, it can be seen that the Pickering high internal phase emulsion prepared with a mass ratio of whey protein isolate to gum arabic of 1:2 has a smaller particle size, a more uniform microstructure distribution, and more excellent rheological properties. Therefore, when the mass ratio of whey protein isolate to gum arabic is 1:2, it is selected as the optimal ratio of this technical solution, and the prepared Pickering high internal phase emulsion is used for further blending with carrot juice subsequently.

[0085] III. Analysis of the addition ratios of each component in step S4 on the experimental results

[0086] 1. Sensory evaluation criteria

[0087] The following table's indicators are used to analyze the experimental results.

[0088] Table 1 Sensory scoring table

[0089]

[0090] 2. Influence of the emulsion addition amount on the sensory quality of the beverage

[0091] Based on Example 1, the emulsion addition amount in step S4 is experimentally analyzed at 5%-25% respectively, and the remaining steps are the same as in Example 1.

[0092] As Figure 13 (A), as the emulsion addition amount increases, the sensory score first rises and then falls. The orange-yellow color of the compound beverage gradually fades, and the taste gradually becomes mellow. When the emulsion addition amount reaches 10%, the aroma and taste of the compound beverage are the best, delicate and smooth. When the addition amount exceeds 20%, the compound beverage becomes thicker and has a heavier greasy feeling, and the sensory score decreases.

[0093] 3. Influence of stabilizer addition amount on sensory quality

[0094] On the basis of Example 1, the addition amount of stabilizer in step S4 was experimentally analyzed at 0.01%-0.1% respectively, and the other steps were the same as those in Example 1.

[0095] As Figure 13 (B), as the addition amount of stabilizer increases, the sensory score first rises and then falls. The texture of the freshly prepared beverage gradually becomes uniform, and the layering phenomenon improves. When the addition amount of the emulsion reaches 0.03%, the compound beverage has no obvious layering. When the addition amount exceeds 0.05%, the texture of the compound beverage is uniform, but the taste is too viscous and the sensory score decreases.

[0096] 4. Influence of white granulated sugar addition amount on sensory quality

[0097] On the basis of Example 1, the addition amount of white granulated sugar in step S4 was experimentally analyzed at 4%-12% respectively, and the other steps were the same as those in Example 1.

[0098] As Figure 13 (C), as the amount of white granulated sugar increases, the taste of the compound beverage first increases and then decreases. When the addition amount of white granulated sugar is less than 4%, the taste of the compound beverage is too light. When the addition amount is 6%, the taste is moderate. As the addition amount increases, the taste improves and the sensory score gradually increases. However, when the addition amount is too high, the sweetness of the compound beverage is too high and the taste is too sweet and greasy, and the sensory score will decrease.

[0099] 5. Influence of citric acid addition amount on sensory quality

[0100] On the basis of Example 1, the addition amount of citric acid in step S4 was experimentally analyzed at 0.04%-0.12% respectively, and the other steps were the same as those in Example 1.

[0101] As Figure 13 (D), as the addition amount of citric acid increases, the sensory score of the compound beverage first increases and then decreases. When the addition amount of citric acid is less than 0.06%, the taste of the compound beverage is too sweet. When the addition amount is 0.08%, the taste is the best, sweet and sour. As the addition amount gradually increases, the taste of the compound beverage becomes sour and astringent, the taste is not good, and the sensory score is low.

[0102] 6. Analysis of orthogonal test results

[0103] Table 2 Orthogonal test result table

[0104]

[0105] The best combination obtained by orthogonal analysis is A1B1C3D1, while the combination with the highest score in the orthogonal experiment is A2B2C3D1, and the results of the two are inconsistent. To determine the optimal formula, A1B1C3D1 and A2B2C3D1 were verified, and each combination was replicated three times. As can be seen from Table 4, the best formula combination is A2B2C3D1, that is, the emulsion addition amount is 10%, the stabilizer addition amount is 0.03%, the white granulated sugar addition amount is 8%, and the anhydrous citric acid addition amount is 0.06%.

[0106] Table 3 Verification experiment

[0107]

[0108] 7. Bioaccessibility analysis

[0109] The bioaccessibility of carotenoids after digestion was studied through an in vitro digestion model, and a comparative analysis was carried out with carrot juice. According to the changes in carotenoid content at each digestion stage, the changes of the safflower oil emulsion-carrot juice compound beverage in the human body were preliminarily explored, and the bioaccessibility of carotenoids was calculated.

[0110] As shown in Table 4, after gastric simulated digestion and intestinal simulated digestion, the carotenoid contents of the Pickering high internal phase emulsion-carrot juice compound beverage and carrot juice decreased by 2.12 mg / kg and 5.10 mg / kg respectively, and the bioaccessibilities were 79.20% and 57.12% respectively. Compared with carrot juice, the bioaccessibility of the compound beverage increased by 22.08%, and the compound beverage has higher nutritional value.

[0111] Table 4 Carotenoid content during in vitro digestion simulation

[0112]

[0113] The present invention selects vegetable oils rich in a large amount of unsaturated fatty acids such as safflower oil, walnut oil, pumpkin seed oil, linseed oil, seabuckthorn fruit oil, etc., develops an oil-in-water (O / W) Pickering high internal phase emulsion stabilized by natural components, and applies it to the preparation of carrot juice compound beverage, and obtains a compound carrot juice with good stability and high carotenoid bioavailability and its preparation process, which has important significance for the food processing industry and meeting the nutritional needs of consumers.

[0114] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those of ordinary skill in the relevant technical field can also make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention, and the patent protection scope of the present invention should be defined by the claims.

Claims

1. A Pickering high internal phase emulsion - carrot juice compound beverage, characterized in that: It includes Pickering high internal phase emulsion, carrot juice, granulated sugar, citric acid and xanthan gum. The proportion of the Pickering high internal phase emulsion is: 5 - 15% (w / w); the proportion of the carrot juice is: 76.87 - 90.95% (w / w); the proportion of the granulated sugar is: 4 - 8% (w / w); the proportion of the citric acid is: 0.04 - 0.08% (w / w); the proportion of the xanthan gum is: 0.01 - 0.05% (w / w); The Pickering high internal phase emulsion includes edible oil, whey protein isolate, gum arabic and water. The proportion of the edible oil is: 75% (v / v); the proportion of the whey protein isolate is: 1 - 3% (w / v); the proportion of the gum arabic is: 1 - 3% (w / v); the remaining component is water.

2. The Pickering high internal phase emulsion-carrot juice compound beverage according to claim 1, characterized in that: The edible oil is one or a mixture of safflower oil, walnut oil, linseed oil, grape seed oil, perilla oil, olive oil.

3. A Pickering high internal phase emulsion - carrot juice compound beverage according to claim 1, characterized in that: The proportion of the Pickering high internal phase emulsion is 10% (w / w), the proportion of the carrot juice is 81.89% (w / w), the proportion of the granulated sugar is 8% (w / w), the proportion of the citric acid is 0.08% (w / w), the proportion of the xanthan gum is 0.03% (w / w); In the Pickering high internal phase emulsion, the proportion of the edible oil is 75% (v / v), the proportion of the whey protein isolate is 1% (w / v), the proportion of the gum arabic is 2% (w / v), and the remaining components are water.

4. A preparation process of Pickering high internal phase emulsion - carrot juice compound beverage, characterized in that, It includes the following steps: S1: Prepare whey protein isolate - gum arabic nanocomposite Dissolve whey protein isolate and gum arabic at room temperature, pH = 10.0 ± 0.5, stir for 3 - 4 h until completely dissolved, adjust the pH to 7.0 ± 0.5, and stir for 1 - 2 h; the added mass ratio of whey protein isolate to gum arabic is 3:1 - 1:3 to obtain a whey protein isolate - gum arabic nanocomposite with a solids content of 3%. S2: Prepare Pickering high internal phase emulsion Slowly add one or a mixture of safflower oil, walnut oil, linseed oil, grape seed oil, perilla oil, olive oil to the whey protein isolate - gum arabic nanocomposite emulsion, and perform high - speed shear homogenization. The oil - phase volume fraction is 75% to obtain a Pickering high internal phase emulsion; S3: Prepare carrot juice Wash and boil carrots, then make a pulp with pure water, and filter to obtain carrot juice; S4: Slowly add the carrot juice to the Pickering high internal phase emulsion, stir evenly, and add xanthan gum, granulated sugar, and citric acid for blending to obtain a Pickering high internal phase emulsion - carrot juice compound beverage. The addition amount of the emulsion is 5% - 15% of the total mass of the compound beverage, the addition amount of xanthan gum is 0.01% - 0.05% of the total mass of the compound beverage, the addition amount of granulated sugar is 4% - 8% of the total mass of the compound beverage, and the addition amount of citric acid is 0.04% - 0.08% of the total mass of the compound beverage.

5. The preparation process of a Pickering high internal phase emulsion - carrot juice compound beverage according to claim 4, characterized in that: In step S1, the added mass ratio of whey protein isolate to gum arabic is 1:

2.

6. The preparation process of a Pickering high internal phase emulsion - carrot juice compound beverage according to claim 4, characterized in that: In the step S3, the boiling water cooking before the carrot juice preparation is boiling water cooking for 4 minutes, and the mass ratio of the carrot to the purified water during pulping is 1:

1.

7. The preparation process of a Pickering high internal phase emulsion - carrot juice compound beverage according to claim 4, characterized in that: In the step S4, the addition amount of the emulsion is 10% of the total mass of the compound beverage.

8. A preparation process of a Pickering high internal phase emulsion - carrot juice compound beverage according to claim 4, characterized in that: In the step S4, the addition amount of xanthan gum is 0.03% of the total mass of the compound beverage.

9. The preparation process of a Pickering high internal phase emulsion - carrot juice compound beverage according to claim 4, characterized in that: In the step S4, the addition amount of the granulated sugar is 8% of the total mass of the compound beverage.

10. A preparation process of a Pickering high internal phase emulsion - carrot juice compound beverage according to claim 4, characterized in that: In the step S4, the addition amount of the citric acid is 0.06% of the total mass of the compound beverage.

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