Novel nanobubble technology and application of nanobubble technology in ice cream product

Abstract

The invention belongs to the technical field of food, and particularly relates to application of a novel nanobubble technology in ice cream products. The nanobubble technology comprises the step of adding nanobubble water produced by a micro-nanobubble generator; the ice cream contains an added fat substitute. The invention provides zero-trans low-saturation ice cream with excellent melting performance and mouthfeel prepared by a nano-bubble technology, which comprises the following steps: adding a fat substitute containing oleogel and having an oil-water ratio of 7: 3 into an ice cream mixed solution, replacing first-grade water with nano-bubble water, emulsifying by high-speed shearing in a water bath, cooling overnight, and adding the nano-bubble water into the ice cream mixed solution to obtain the nano-bubble ice cream. And preparing the ice cream in an ice cream machine. The prepared ice cream contains zero-trans low-saturated fatty acid, and has the advantages of strong melting resistance, high sensory evaluation, simple preparation process, easy realization of industrialization, and green, healthy and economic raw materials. The method can be used for large-scale industrial production of ice cream, ice crystal coarsening, ice cream deformation and the like in the transportation process are avoided, and meanwhile higher sensory evaluation is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of food technology, and more specifically, relates to a novel nano bubble technology and its application in ice cream products. Background Art

[0002] As the quality of human life improves, society pays more and more attention to health, and the nutritional value and flavor of food are of great concern to the market. Today, industrial scientists and researchers are working hard to develop healthy food. Ice cream is a frozen food with expanded volume, made from drinking water, milk, milk powder (or vegetable oil), sugar, etc. as the main raw materials, with appropriate amount of food additives added, and made through mixing, sterilization, homogenization, aging and hardening processes. Ice cream is a product that provides nutritional value and clears away heat and relieves summer heat, which is very popular among consumers. However, the high sugar and high fat content of ice cream on the market will bring health risks such as obesity; the product will melt and deform during the transportation of ice cream products; the re-growth of ice crystals inside the ice cream during storage will cause a rough taste and the growth of microorganisms. Therefore, the production of low-fat, healthy, anti-melting and good-tasting ice cream products has become a research trend.

[0003] In the preparation of ice cream, a series of processes are required to form an emulsion, which is then frozen, stirred, and aerated to form frozen foam. It is composed of bubbles dispersed in a water matrix and contains a complex colloid of gas-liquid-solid phases. The three main structural components of ice cream are bubbles, ice crystals, and fat globules. The bubbles stabilized by partially aggregated fat crystals play a vital role in the organizational structure of ice cream.

[0004] The current research status of ice cream mainly focuses on the following three aspects: fat substitutes, types of stabilizers and preparation methods. Liyang Du, ZO NG Meng and others used monoglyceride-based oil gel and oil foam as fat substitutes in ice cream production. Ice cream containing 50% oil gel has an appropriate partial aggregation degree (PCD is 44.17%), and the complete network structure gives it an ideal quality and produces a perceptible frankincense. Adding candelilla wax to hemp seed oil and palm oil is beneficial to the general stability of frozen desserts, and increases viscosity and elasticity, resulting in higher sensory evaluation. Adding stabilizers to ice cream can effectively increase the viscosity of the slurry, inhibit the growth of ice crystals, and improve the taste of ice cream. Milk protein is a natural animal protein that can be used as an emulsifier and stabilizer in the ice cream system. It increases the viscosity of the adsorption film, electrostatic repulsion and steric hindrance by generating intermolecular interactions with oils, polysaccharides, etc., thereby preventing droplet aggregation and achieving the purpose of improving ice cream stability. Relevant researchers use a combination of different types of stabilizers to greatly improve the physical quality and sensory properties of ice cream. The use of ultrasound in the production process reduces the total energy required to freeze ice cream. The effect of ultrasound-assisted freezing on its crystal structure results in a product with smaller, more evenly distributed, and more regular crystals. This improves the quality of the product and shortens its freezing time. For large-scale ice cream production, ultrasound equipment is expensive and will increase production costs.

[0005] As a new field, nanobubbles have low production equipment costs and are suitable for large-scale production. Studies have shown that the introduction of nanobubbles into anhydrous milk fat can provide heterogeneous nucleation sites for the system, which helps to shorten the freezing time and form small and numerous crystals. At present, there are no reports on the application of nanobubbles in ice cream. This study aims to explore the application potential of nanobubble technology in ice cream food and develop a low-fat healthy ice cream product with a dense and smooth taste, high stability and storage performance. Summary of the invention

[0006] In order to overcome the above-mentioned deficiencies of the prior art, the primary purpose of the present invention is to provide a novel method for preparing nanobubbles.

[0007] The second object of the present invention is to provide the above-mentioned water-in-oil gel fat substitute.

[0008] The third object of the present invention is to provide the above-mentioned nanobubbles and application thereof in ice cream.

[0009] In order to achieve the purpose of the present invention, the following technical solutions are used: A novel method for preparing nanobubbles comprises taking 600 ml of first-grade water, using a micro-nano bubble generator with an air flow rate set to 80 ml / min and a time set to 15 min, to produce nanobubble-rich water.

[0010] A water-in-oil gel cream substitute comprises an oil phase and a water phase prepared as a water-in-oil cream; the oil phase comprises edible oil added with an oil gelling agent; the water phase comprises a water solvent added with xanthan gum; the oil gelling agent can be one or more of beeswax, rice bran wax, candelilla wax, monoglyceride, sunflower wax and palm wax.

[0011] As a preferred technical solution, the edible oil can be one or more of rice bran oil, rapeseed oil, soybean oil, sunflower seed oil, peanut oil, olive oil, and corn oil.

[0012] As a preferred technical solution, the concentration of the oil gel in the edible oil is 0.1% wt~10% wt.

[0013] As a more preferred technical solution, the oil gel concentration in the edible oil is 5% wt~10% wt.

[0014] As a preferred technical solution, the concentration of xanthan gum in water is 0.1% wt~8% wt.

[0015] As a more preferred technical solution, the water-oil volume ratio is 3:7.

[0016] As a preferred technical solution, the water bath temperature is 85-90°C, and the shear emulsification condition is high-speed homogenization at 14000 r / min for 1 min.

[0017] A nano bubble and its application in ice cream, comprising a fat substitute and water to prepare an ice cream emulsion; the water contains a water solvent added with milk powder, sucrose, guar gum, carrageenan and lecithin.

[0018] As a preferred technical solution, the water bath temperature is 85°C, and the shear emulsification conditions are high-speed homogenization at 8000 r / min for 4 min.

[0019] The present invention uses a water-in-oil gel fat substitute, which is a semi-solid structure. The supramolecular gel technology is used to confine liquid vegetable oil in the gel network, thereby constructing a stable structure that reduces the body's fat intake in ice cream. More importantly, this study introduces nanobubble technology to achieve rapid freezing, regulate the size of ice cream crystals, form many small crystals, improve the ice cream's anti-melting performance, and overcome the problem of rough taste caused by coarse ice crystals.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: The water-in-oil gel fat substitute used in the present invention reduces the content of saturated fat and trans fatty acids in ice cream, can significantly improve the health of consumers, and reduce the risks of cardiovascular and metabolic diseases; the present invention uses nanobubble technology as a means of regulating ice cream crystallization, the preparation method is simple and fast, the cost is low, and it is easy to mass produce. The prepared ice cream has a dense and smooth taste, is green, healthy and cost-effective preparation process technology, and provides a new direction for improving the processing technology of frozen products. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 These are the appearance pictures of different ice cream emulsions. From left to right, they are ice cream emulsion containing butter, ice cream emulsion containing only fat substitute, ice cream emulsion containing fat substitute and introducing nanobubble technology. Figure 2 The microscopic results of different ice cream emulsions are shown in Figure 1. From left to right, they are ice cream emulsion containing butter, ice cream emulsion containing only fat substitute, ice cream emulsion containing fat substitute and introducing nanobubble technology. Figure 3 This is the particle size analysis result of ice cream emulsion; Figure 4 This is the effect diagram of the viscosity test of ice cream emulsion; Figure 5 This is the appearance of the final ice cream, from left to right: ice cream containing butter, ice cream containing only fat substitute, ice cream containing fat substitute and introducing nanobubble technology; Figure 6 , 7 is a graph showing the melting results of ice cream embodiments 1, 2 and 3 over time; DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Unless otherwise specified, the experimental methods used in the examples of the present invention are all conventional methods; the materials and reagents used are all reagents and materials that can be obtained from commercial channels unless otherwise specified. Example 1

[0024] Preparation of a butter commercial ice cream: A certain amount of butter, skim milk powder, sucrose, corn syrup, guar gum, carrageenan and lecithin were accurately weighed and dissolved in primary water to prepare a mixed solution with a mass concentration of 10% for butter and skim milk powder, a mass concentration of 12% for sucrose, a mass concentration of 4% for corn syrup, a mass concentration of 0.1% for guar gum, a mass concentration of 0.015% for carrageenan and a mass concentration of 0.4% for lecithin. Then, the mixture was heated and stirred in a water bath at 85°C until the sample was completely mixed. The mixed sample was sheared at a shear rate of 8000 rpm for 4 min to completely emulsify the system. Then, the sample was placed at 4°C and stored overnight to obtain an ice cream emulsion. The ice cream slurry after aging overnight was placed in an ice cream machine and frozen and whipped for 2 h. The whipped ice cream was divided into round containers and placed in a -18°C refrigerator for 24 h to obtain butter commercial ice cream. Example 2

[0025] Accurately weigh a certain amount of stearic acid and myristic acid, where the total mass concentration of the composite gel factor is 10%: the mass concentration of stearic acid is 2%, and the mass concentration of myristic acid is 8%, and dissolve them in 100g of sunflower oil to obtain the oil phase of the fat substitute; weigh 1% of xanthan gum by mass and dissolve it in a certain amount of primary water to obtain the water phase. With an oil-water ratio of 7:3, shear the system at a shear rate of 14000rpm for 1min in a shear emulsifier to completely emulsify the system to obtain a fat substitute. Then, according to the mass concentrations of fat and butter of 10%, the mass concentration of sucrose of 12%, the mass concentration of corn syrup of 4%, the mass concentration of guar gum of 0.1%, the mass concentration of carrageenan of 0.015%, and the mass concentration of lecithin of 0.4%, heat and dissolve them in primary water at 85℃. After the system is uniform, shear the system at a shear rate of 8000 rpm for 4 min using a shearing machine to completely emulsify the system. Then, the sample is stored at 4℃ overnight to obtain an ice cream emulsion. The ice cream slurry after aging overnight was placed in an ice cream machine and frozen and whipped for 2 h. The whipped ice cream was divided into round containers and placed in a -18°C refrigerator for 24 h to obtain ice cream. Example 3

[0026] A micro-nano bubble generator was used to prepare 600 ml of nanobubble-rich water at an air flow rate of 80 ml / min for 15 min. A certain amount of stearic acid and myristic acid was accurately weighed, wherein the total mass concentration of the composite gel factor was 10%: the mass concentration of stearic acid was 2%, and the mass concentration of myristic acid was 8%, and dissolved in 100 g of sunflower oil to obtain the oil phase of the fat substitute; 1% of xanthan gum was weighed and dissolved in a certain amount of nanobubble water to obtain the water phase. The system was completely emulsified at an oil-water ratio of 7:3 in a shear emulsifier at a shear rate of 14000 rpm for 1 min to obtain a fat substitute. Then, the mass concentrations of fat and butter were 10%, the mass concentration of sucrose was 12%, the mass concentration of corn syrup was 4%, the mass concentration of guar gum was 0.1%, the mass concentration of carrageenan was 0.015%, and the mass concentration of lecithin was 0.4%. They were heated and dissolved in nanobubble water at 85°C. After the system was uniform, a shearing machine was used to shear at a shear rate of 8000 rpm for 4 min to completely emulsify the system. Then, the sample was placed at 4°C and stored overnight to obtain an ice cream emulsion. The ice cream slurry after aging overnight was placed in an ice cream machine and frozen and whipped for 2 h. The whipped ice cream was divided into round containers and placed in a -18°C refrigerator for 24 h to obtain ice cream.

[0027] The difference between Examples 1, 2 and 3 is that the water-in-oil gel emulsion is used instead of butter, and nanobubbles are added to prepare ice cream.

[0028] In order to further illustrate the technical effect of the scheme of the present invention, the macro and micro structures of the ice cream emulsion prepared in the example and the performance of the ice cream are experimentally analyzed below.

[0029] Test Example 1 Appearance Test The ice cream emulsions prepared in Example 1, Example 2, and Example 3 were used as test samples for macroscopic and microstructural observations. The structure and crystal distribution of the ice cream were observed under polarized light using an Olympus microscope. The test results are shown in FIG. Figure 1 , 2 .

[0030] Figure 1 The macroscopic images of the ice cream emulsions of Example 1, Example 2, and Example 3 show that Example 1 is obviously light yellow, while the other two groups are whitish. After inversion, there is no obvious stratification or flow phenomenon in Examples 2 and 3. Figure 2The microstructure of the ice cream emulsions of Example 1, Example 2, and Example 3 shows that the crystal particles of Example 1 are typically spherical in shape and are larger in size, which is a unique crystal morphology of butter; the crystals of Example 2 and Example 3 are needle-shaped, with smaller bubble groups and uniform distribution. Studies have shown that smaller crystal particles can give products a better taste.

[0031] Test Example 2 Particle size distribution test The Malvern laser particle size analyzer was used to measure the particle size of the sample. During the test, water was used as the dispersion medium with a refractive index of 1.33. Table 1 shows the numerical values ​​of the ice cream emulsion particle size.

[0032] Table 1 Example 1 Example 2 Example 3 <![CDATA[D 4,3 (μm)]]> <![CDATA[16.6±0.40 a ]]> <![CDATA[9.34±0.52 b ]]> <![CDATA[8.59±0.08 b ]]> pass Figure 3 It can be seen from Table 1 that the particle size of each group of experiments presents a relatively large single peak distribution. Compared with Example 1, the particle size distribution of Examples 2 and 3 is smaller, concentrated below 10 μm. This may be due to the low melting points of stearic acid and myristic acid in Examples 2 and 3, which are in liquid form during the homogenization process and are prepared after shear homogenization, resulting in a better emulsification effect. In addition, there is another peak at around 100 μm, which may be partially aggregated fat globules. Among them, the peak area of ​​Example 1 is the largest, reaching nearly 2%. Therefore, it can be seen that fat globules are prone to aggregation in samples using butter as the fat phase.

[0033] Test Example 3 Viscosity Test The viscosity of the emulsion sample was tested using a HAAKE rheometer. A flat probe with a diameter of 20 mm and a gap of 0.5 mm was selected, and an appropriate amount of sample was placed on the sample test table. The shear rate was set to 0.1-100 1 / s and the temperature was set to 4°C for measurement.

[0034] Figure 4 The results of viscosity analysis of ice cream slurry are shown. When the shear rate increases, the viscosity of all samples decreases, showing a shear thinning phenomenon, which is a typical non-Newtonian fluid.

[0035] The viscosity of Example 3 is the highest. This may be because in a system containing oil, the viscosity of the system is mainly dominated by the crystal network of the fat phase. Combining the macroscopic and microscopic results, it can be seen that the addition of gelling factor in the oil phase will increase the viscosity of the ice cream emulsion. At the same time, it is found that the crystal size of Example 3 is the smallest, so its cross-linking forms a tighter network, which enhances the viscosity of the system.

[0036] Test Example 4: Full Texture Analysis The textural properties of ice cream were obtained by texture profile analysis. For the double cycle compression test, a sample (40 mm in diameter; 60 mm in height) with an attached probe (P / 5; φ5 mm) was used to measure the force-time curve of the soft serve. The sample was stably fixed in the center of the platform using a sterile container during the test. The test was performed as follows: pre-test speed was 5.0 mm / s, post-test speed was 2.0 mm / s, and the compressive strain was 45%. Table 2 shows the results of the full texture analysis of the ice cream.

[0037] Table 2 Analysis of the overall texture of ice cream hardness brittleness Adhesion Chewability Stickiness Example 1 <![CDATA[96.922±6.44 c ]]> <![CDATA[53.4±8.23 c ]]> <![CDATA[224.79±4.61 c ]]> <![CDATA[5.84±1.50 b ]]> <![CDATA[11.64±0.96 b ]]> Example 2 <![CDATA[120.424±6.45 b ]]> <![CDATA[102.856±11.12 b ]]> <![CDATA[333.065±7.36 b ]]> <![CDATA[8.04±2.83 b ]]> <![CDATA[14.661±1.90 b ]]> Example 3 <![CDATA[433.56±2.35 a ]]> <![CDATA[289.62±38.96 a ]]> <![CDATA[523.12±20.67 a ]]> <![CDATA[52.07±5.37 a ]]> <![CDATA[72.616±7.27 a ]]> In the results of the full texture analysis shown in Table 2, all indicators of Example 3 are significantly higher than those of Example 1 and Example 2, because the fine lactose crystals after freezing form a dense space, which enhances the hardness of the system. At the same time, the bubble group after freezing and whipping still has strong viscosity. The chewiness is significantly higher than the other two groups, which enhances the rebound ability of ice cream after force extrusion, increases the number of chewing times of ice cream in the mouth, prolongs the perception time of ice cream in the mouth, is conducive to improving the oral perception of ice cream, and also gives the ice cream a smoother taste.

[0038] Test Example 5 Melting Rate Test The original shape (40 mL) of the frozen ice cream sample was placed on a stainless steel mesh with a pore size of 2 mm (10 holes / 2.54 cm), and placed on a sample box to melt it in a 20°C incubator. The melted ice cream that passed through the stainless steel mesh was collected and weighed once per second for a total of 60 min. The melting rate of the ice cream was calculated based on the weight percentage of the melted ice cream, and photos were taken every 10 minutes to record the test results. Figure 6 , 7 .

[0039] The melting characteristics of ice cream are one of the important factors in evaluating its quality. Ice cream with a slower melting rate will have a relatively harder texture and will not be too sticky when eaten. If the ice cream melts quickly, it will affect the quality of the ice cream during transportation. Figure 6 From the results of Experimental Example 3, it can be seen that each group melted completely in about 1 hour. At the first melting point, Example 1 was the fastest at about 8 minutes, and Example 3 was the slowest at 18 minutes. Studies have shown that the melting rate of ice cream is mainly affected by viscosity and the aggregation of the fat part. The higher the viscosity, the more flow obstacles the slurry produced by melting ice cream will face. The results of Experimental Example 3 show that the ice cream slurry of Example 4 has the highest viscosity. The results of Experimental Example 2 show that the fat globule aggregation of Example 1 is the highest, and too high an aggregation will make the ice cream easily unstable and cause rapid separation of oil and water. Therefore, Example 1 melts faster, and the melting process of Example 3 is longer.

[0040] Based on the experimental results of the embodiments, it can be obtained that compared with the ice cream containing butter, the ice cream containing only fat substitutes, and the ice cream containing fat substitutes and introducing nanobubble technology, the ice cream sample containing fat substitutes and introducing nanobubble technology can achieve lipid reduction while having better stability and anti-melting performance.

[0041] The above embodiments of the present invention are merely examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation methods of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A novel nanobubble and its application in ice cream products, characterized in that: The invention comprises an oil phase and an aqueous phase prepared into an oil-gel-in-water emulsion; the oil phase comprises edible oil added with an oleogel; the aqueous phase comprises an aqueous solution added with xanthan gum and nanobubbles; the edible oil can be one or more of soybean oil, corn oil, sunflower seed oil, peanut oil, coconut oil, camellia oil, etc.; the oleogel can be one or more of stearic acid, myristic acid, beeswax, rice bran wax, candelilla wax, monoglyceride, sunflower wax, palm wax.

2. The ice cream prepared by nanobubble technology according to claim 1, characterized in that: The edible oil can be one or more of rice bran oil, rapeseed oil, soybean oil, sunflower seed oil, peanut oil, olive oil, and corn oil.

3. A method for producing ice cream using nanobubble technology as claimed in claim 1, characterized in that: The method comprises adding nanobubbles into an ice cream mixed solution, then adding an oil gel-in-water emulsion containing the nanobubbles, emulsifying the emulsion by shearing in a water bath, cooling the emulsion at 4°C overnight to fully age the emulsion, and obtaining an ice cream solution; placing the aged ice cream emulsion in an ice cream machine and stirring it for 2 hours, and cooling it at -18°C for 24 hours to obtain ice cream.

4. The method for preparing the water-in-oil gel emulsion according to claim 3, characterized in that: The concentration of gelling factor in sunflower oil was 10%, and the concentration of xanthan gum in aqueous solution was 1%.

5. The method for preparing the water-in-oil gel emulsion according to claim 3, characterized in that: The concentration of the oil phase in the water-in-oil gel emulsion is 60%~80%.

6. The method for preparing the water-in-oil gel emulsion according to claim 3, characterized in that: The concentration of water phase in the water-in-oil gel emulsion is 20%~40%.

7. The method for preparing the water-in-oil gel emulsion according to claim 3, characterized in that: The water bath temperature was 85-90°C, and the shear emulsification condition was high-speed homogenization at 14,000 r / min for 1 min.

8. The method for preparing nanobubbles according to claim 3, characterized in that: The concentration of nanobubbles in ice cream is 100%.

9. The method for preparing ice cream produced by nanobubble technology according to claim 3, characterized in that: The water bath temperature was 85-90°C, and the shear emulsification condition was high-speed homogenization at 8000 r / min for 4 min.

10. The method for preparing ice cream produced by nanobubble technology according to claim 3, characterized in that: The mass concentration of fat in the ice cream is 10%wt, the mass concentration of sucrose is 12%wt, the mass concentration of corn syrup is 4%wt, the mass concentration of guar gum is 0.1%wt, the mass concentration of carrageenan is 0.015%wt, and the mass concentration of lecithin is 0.4%wt.

11. The nanobubble technology of claim 1 and its application in ice cream products.

12. The use according to claim 9, characterized in that: The fat part in the ice cream is an emulsion of water in oil gel.

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