High-temperature sterilized modified milk and preparation process thereof

Abstract

The invention relates to the technical field of dairy product processing, and particularly discloses high-temperature sterilized modified milk and a preparation process thereof. The high-temperature sterilized modified milk is prepared from the following components in percentage by mass: 0.21 to 0.57 percent of phytosterol ester, 0.05 to 0.35 percent of DHA algal oil, 1 to 2.5 percent of a protective agent, 0.05 to 0.1 percent of a compound stabilizer, 3 to 7 percent of carbohydrates, 0.5 to 1.5 percent of inulin and the balance of raw milk, the protective agent is prepared from yeast beta-glucan, beta-cyclodextrin, lecithin and tea polyphenol. According to the preparation process disclosed by the invention, the high-temperature retention rate and bioavailability of the phytosterol ester and the DHA algal oil are effectively improved, meanwhile, the problems of product layering and non-uniform texture caused by floating of fat and sterol ester in the storage period of the modified milk are reduced, and the shelf life of the product is effectively prolonged.

Description

Technical Field

[0001] This application relates to the technical field of dairy product processing, and more specifically, it relates to a high-temperature sterilized formulated milk and its preparation process. Background Art

[0002] Cholesterol level has become one of the important indicators for modern people to pay attention to health. Its abnormal metabolism is the core inducement for hyperlipidemia, atherosclerosis and cardiovascular and cerebrovascular diseases. According to the statistical data of the World Health Organization (WHO) on the global health status, the total cholesterol levels of more than 1 / 3 of the adults in the world are above the standard level. Affected by diet and living habits, the cholesterol level of the Chinese population has become one of the highest in the world. At present, clinically, statins are mainly relied on to reduce cholesterol, but long-term use of drugs may be accompanied by side effects such as elevated liver enzymes and muscle pain. People hope to achieve the goal of reducing cholesterol levels from the perspective of dietary intervention through non-drug cholesterol management approaches.

[0003] With the increasing attention of consumers to healthy foods, the functional dairy product market has grown rapidly. Ultra-high temperature (UHT) sterilized formulated milk can maximize the sensory quality and nutritional components in dairy products, and is convenient to eat, has a long shelf life, and is suitable for long-distance transportation. Therefore, high-temperature sterilized functional formulated milk occupies an increasingly important market share in the dairy product market.

[0004] Related research has confirmed that phytosterol components can competitively hinder the absorption of cholesterol by the digestive system, thus significantly reducing the levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL) absorbed by the human body in the blood, effectively reducing the incidence of coronary heart disease and hyperlipidemia in the population, and becoming an important functional raw material for formulated milk.

[0005] However, for the above related technologies, the inventor found that in liquid dairy products, phytosterols with extremely strong hydrophobicity are very difficult to be evenly dispersed in the dairy product system, and will agglomerate and float up in a very short time after processing, with obvious stratification. Although the solubility and dispersibility of esterified phytosterol esters are better than those of free sterols, when applied to the preparation of liquid dairy products, their stability is still not ideal. Especially when preparing high-temperature sterilized formulated milk, phytosterol esters are prone to oxidation and isomerization and loss under high-temperature sterilization conditions, resulting in a decrease in the retention rate, reducing their competitive binding ability with cholesterol. At the same time, phytosterol esters are prone to oxidation at high temperatures and produce oxidized off-flavors, affecting the product flavor. In addition, high-temperature sterilized formulated milk is a complex multi-component system of proteins, fats and functional additives, and is prone to problems such as the floating of sterol esters and fats and the precipitation of protein denaturation during high-temperature sterilization and storage, directly affecting the nutritional value, taste flavor and shelf life of the product. Summary of the Invention

[0006] In order to improve the stability of high-temperature sterilized formula milk containing plant sterol esters, thereby ensuring the cholesterol-lowering ability, taste and flavor, and nutritional value of the high-temperature sterilized formula milk and extending the shelf life of the product, the present application provides a high-temperature sterilized formula milk and a preparation process thereof.

[0007] In a first aspect, the present application provides a high temperature sterilized modulated milk, which adopts the following technical solution: A high-temperature sterilized modulated milk, comprising, by mass percentage, 0.21-0.57% of phytosterol ester, 0.05-0.35% of DHA algae oil, 1-2.5% of a protective agent, 0.05-0.1% of a composite stabilizer, 3-7% of a carbohydrate substance and 0.5-1.5% of inulin, with the remainder being raw milk; The protective agent comprises yeast beta-glucan, beta-cyclodextrin, lecithin and tea polyphenols.

[0008] By adopting the above technical scheme, plant sterol esters, DHA algae oil and inulin are quantitatively combined as functional ingredients. The synergy of DHA and sterol esters achieves a dual-effect lipid-lowering effect, giving the formula milk of the present application the function of lowering cholesterol and regulating blood lipids, which helps to promote cardiovascular health. Inulin, as an aqueous dietary fiber component, synergizes with plant sterol esters to effectively promote the metabolism of intestinal cholesterol, further enhances the cholesterol-lowering effect, and maintains intestinal health.

[0009] Further, the present application uses yeast β-glucan, β-cyclodextrin, lecithin and tea polyphenols as protective agents to form a physical barrier in the outer layer of plant sterol esters and DHA algae oil for protection, effectively reducing the isomerization caused by sterol esters during the high temperature sterilization process, improving the retention rate of sterol esters in high temperature sterilization modulated milk, and reducing the oxidation problem of DHA algae oil during the preparation process. The trace use of tea polyphenols enhances the antioxidant properties of the system, inhibits the oxidative decomposition of plant sterol esters and DHA algae oil during high temperature sterilization, and reduces the bitter taste that may be brought by plant sterol esters, improves the taste and flavor of modulated milk, and significantly improves the stability and effectiveness of plant sterol esters and DHA algae oil in high temperature sterilization modulated milk. In addition, yeast β-glucan has a significant effect in lowering blood sugar, reducing fat and improving immunity, and the combined use with plant sterol esters achieves a double-effect cholesterol-lowering effect.

[0010] Optionally, the protective agent includes yeast β-glucan, β-cyclodextrin, lecithin and tea polyphenols in a mass ratio of (10-15):(7-10):(2-4):(0.1-0.5).

[0011] Optionally, the composite stabilizer includes gellan gum, xanthan gum and light calcium in a mass ratio of (2-3):(1-2):(3-6).

[0012] By adopting the above technical solution, using gellan gum and xanthan gum as stabilizers can effectively improve the interfacial stability of the modulated milk system. Experiments show that the addition of light calcium carbonate further extends the shelf life of the high-temperature sterilized modulated milk and reduces the layering problem caused by the floating of fat and sterol esters. This is because light calcium carbonate can bind to milk proteins to form a dense micelle network, inhibiting the migration of hydrophobic substances such as milk fat in the modulated milk through physical barrier methods, overcoming the problem of product layering caused by uneven texture such as fat floating during the storage of the modulated milk.

[0013] Optionally, the raw milk is selected from any one of cow milk or goat milk.

[0014] Optionally, the saccharide substance is selected from any one or a combination of sucralose, stevioside, mogroside, and galactooligosaccharide.

[0015] In a second aspect, the present application provides a preparation process for high-temperature sterilized modulated milk, adopting the following technical solution: A preparation process for high-temperature sterilized modulated milk includes the following steps: S1: Dissolve yeast β-glucan in water and stir until completely dissolved to obtain a first solution. Dissolve β-cyclodextrin in water and stir until completely dissolved to obtain a second solution. Mix the first solution and the second solution, add lecithin and tea polyphenols, and stir evenly to obtain a wall material solution; Heat and melt plant sterol ester and DHA algal oil and stir evenly to obtain a core material solution. Add the core material solution to the wall material solution, stir, shear, and homogenize to obtain a microcapsule emulsion, and then perform spray drying to obtain microcapsules of plant sterol ester and DHA algal oil; S2: Heat and stir the raw milk, add microcapsules of plant sterol ester and DHA algal oil, a composite stabilizer, a saccharide substance, and inulin, and then perform a homogenization treatment to obtain a homogenized liquid; S3: Perform high-temperature sterilization on the homogenized liquid at (137 ± 2) °C for 4 - 6 s, and can it after cooling.

[0016] By adopting the above technical solution, in the present application, yeast β-glucan, β-cyclodextrin, lecithin, and tea polyphenols are used as wall materials, and plant sterol ester and DHA algal oil are used as core materials to prepare microcapsules, effectively encapsulating and protecting the functional components of the core materials, significantly inhibiting the denaturation and loss that plant sterol ester and DHA algal oil may suffer during high-temperature sterilization.

[0017] When yeast β-glucan is used as the main wall material to form a heat-resistant barrier to protect phytosterol esters and DHA algal oil, on the one hand, the polysaccharide molecular chain structure forms a three-dimensional structural framework through hydrogen bonding and hydrophobic interactions. On the other hand, the thickening effect of yeast β-glucan helps to form a viscoelastic gel network in the modulated milk system, effectively inhibiting the floating of fat globules and the aggregation and sedimentation of other component particles through viscous resistance, achieving long-term uniform suspension of the core material, and effectively alleviating the problem of easy stratification of traditional modulated milk. As an auxiliary wall material, β-cyclodextrin can adsorb on the surface of the core material particles, reduce the interfacial tension, and effectively improve the dispersion uniformity of the hydrophobic core material and yeast β-glucan in the modulated milk.

[0018] The thickening property of yeast β-glucan and the solubilizing property of β-cyclodextrin work together as wall material protectants, effectively improving the retention rate of phytosterol ester and DHA algal oil core materials in the high-temperature sterilization process flow. At the same time, it ensures the suspension stability of phytosterol ester and DHA algal oil core materials during storage, extends the shelf life of high-temperature sterilized modulated milk, and ensures the taste and flavor of the modulated milk.

[0019] Optionally, the conditions for spray drying the microcapsule emulsion in step S1 are: the feed temperature is 60 - 70 °C, the inlet air temperature is 120 - 140 °C, the hot air flow rate is 0.5 m 3 / min, and the average feed rate is 4 mL / min.

[0020] By adopting the above technical solution, through the method of low-temperature spray drying and optimizing the relationship among the feed temperature, inlet air temperature, hot air flow rate, and feed rate, it is possible to further reduce the loss of phytosterol esters caused by high temperature during spray drying, protect the activity of tea polyphenols, ensure their stability in the microcapsules, and improve the bioavailability.

[0021] Optionally, the conditions for the homogenization treatment in step S3 are: the homogenization pressure is 150 - 280 bar, and the homogenization temperature is 60 - 80 °C.

[0022] In summary, the present application has the following beneficial effects: 1. The present application uses the quantitative combination of phytosterol esters, DHA algal oil, and inulin as functional ingredients to prepare high-temperature sterilized modulated milk, endowing the modulated milk with the dual functions of reducing cholesterol and regulating blood lipids, which is beneficial to protecting cardiovascular health. At the same time, inulin, as a water-soluble dietary fiber component, can effectively promote the metabolism of intestinal cholesterol, further enhancing the effects of the modulated milk in reducing cholesterol and regulating blood lipids and maintaining intestinal health.

[0023] 2. In this application, phytosterol esters and DHA algal oil are used as the core materials, yeast β-glucan is used as the main wall material, and β-cyclodextrin is used as the auxiliary wall material. Through the physical barrier effect, the isomerization or activity loss of the core materials caused by high temperature in the high-temperature sterilization preparation process is effectively reduced, the high-temperature retention rate and suspension stability of phytosterol esters and DHA algal oil are improved, and the trace use of tea polyphenols enhances the antioxidant performance of the microcapsule structure, inhibits the oxidative decomposition of the core materials during high-temperature sterilization, reduces the bitter and strange smell caused by the possible oxidation or isomerization of phytosterol esters, improves the taste and flavor of the formulated milk, effectively ensures the bioavailability of the core materials, and extends the shelf life of the high-temperature sterilized formulated milk.

[0024] 3. In this application, gellan gum and xanthan gum are used as stabilizers, and light calcium is added as a composite stabilizer. Light calcium can combine with milk proteins in the formulated milk system to form a dense micelle network, and at the same time, as physical cross-linking points, it is embedded in the viscoelastic gel network formed by phytosterol esters and DHA algal oil microcapsules with yeast β-glucan and β-cyclodextrin as wall materials, enhancing the interfacial binding strength between various raw material components, inhibiting the free migration of hydrophobic substances such as sterol esters and milk fat, and reducing the product stratification problem caused by uneven texture such as the floating of fat and sterol esters during the storage of the formulated milk. Detailed implementation mode

[0025] The following examples further illustrate this application in detail.

[0026] Raw materials Unless otherwise specified, the raw materials used in the examples and comparative examples of this application are all commercially available food-grade products that can be used for food additives. Specifically: Cow's milk, selected from pastures around Hohhot, is regular milk that meets the requirements of China's fresh cow's milk purchase standard GB6914; Phytosterol esters, selected from Xi'an Highsun Biotech Co., Ltd., are 97% soy phytosterol esters; DHA algal oil, selected from Cabiotec (Wuhan) Co., Ltd., DHA algal oil; Yeast β-glucan, selected from Xi'an Purelife Bioengineering Co., Ltd., PRS-0417; β-Cyclodextrin, selected from Shaanxi Ranken Biotech Co., Ltd., is β-cyclodextrin; Lecithin, selected from Shanxi Qingye Biotech Co., Ltd., QYSW-1024-154; Sodium carboxymethyl cellulose, selected from Eagle Chemical Industry (Shijiazhuang) Co., Ltd., CMC FL100; Tea polyphenols, selected from Shanxi Qingye Biotech Co., Ltd., QYSW-1023-115; Inulin, CAS: 9005-80-5; Gellan gum, selected from Xinjiang Fufeng Biotechnology Co., Ltd., high acyl gellan gum, effective content ≥ 99%; Xanthan gum, selected from Shandong CP Kelco, CAS: 11138-66-2; Light calcium carbonate, selected from Jiangxi Chuangxian Fine Calcium Co., Ltd., 1250 mesh food grade light calcium carbonate; Stevioside, selected from Shanxi Qingye Biotechnology Co., Ltd., QYSW-1024-349; Momordica grosvenori sweet glycoside, selected from Jianchen Ketian Food, 8462. Examples

[0027] Example 1 A high-temperature sterilized modulated milk, the raw materials and their dosages are shown in Table 1. Among them, the protective agent is yeast β-glucan, β-cyclodextrin, lecithin, carboxymethyl cellulose sodium and tea polyphenol with a mass ratio of 13:7:3:1:0.3, the composite stabilizer is gellan gum, xanthan gum and light calcium carbonate with a mass ratio of 2:1:3, and the saccharide substances are sucralose and galactooligosaccharide with a mass ratio of 1:1.2.

[0028] Table 1 Component / % Example 1 Example 2 Example 3 Example 4 Phytosterol ester 0.35 0.42 0.21 0.57 DHA algal oil 0.25 0.35 0.05 0.2 Protectant 1.6 2 1 2.5 Compound stabilizer 0.07 0.06 0.05 0.1 Saccharide substance 5.5 5 3 7 Inulin 0.85 1 0.5 1.5 Milk Up to 100 Up to 100 Up to 100 Up to 100 The preparation method of the above high-temperature sterilized modulated milk includes the following steps: S1: Preparation of microcapsules of phytosterol esters and DHA algal oil (1) Dissolve yeast β-glucan in water at (80 ± 2) °C, stir until completely dissolved to obtain a first solution with a concentration of 8%; (2) Dissolve β-cyclodextrin in water at (65 ± 2) °C, stir until completely dissolved to obtain a second solution with a concentration of 10%; (3) Mix the first solution and the second solution, add lecithin, carboxymethyl cellulose sodium and tea polyphenol, and stir evenly to obtain a wall material solution; (4) Heat and melt phytosterol esters and DHA algal oil at (55 ± 2) °C and stir evenly to obtain a core material solution; (5) Add the core material solution to the wall material solution and stir evenly. After shearing at 10000 rpm for 2 min, first perform homogenization treatment at 25 MPa, then at 45 MPa. The homogenization temperature is 60 °C, and then adjust the pH to 3.5 ± 0.5 to obtain a microcapsule emulsion; (6) Perform spray drying on the microcapsule emulsion. The conditions for spray drying are: the feeding temperature is 60 °C, the inlet air temperature is 120 °C, and the hot air flow rate is 0.5 m 3 / min, the average feeding rate is 4 mL / min, and microcapsules of phytosterol esters and DHA algal oil are obtained; S2: Heat the milk to (45 ± 5) °C, and while stirring, add the microcapsules of phytosterol esters and DHA algal oil, the compound stabilizer, the saccharide substance and inulin. Then, homogenize at 20 MPa first and then at 40 MPa, and the homogenization temperature is 80 °C for both times to obtain the homogenized liquid; S3: Sterilize the homogenized liquid at a high temperature of (137 ± 2) °C for 6 s, and after cooling, can it to obtain the product.

[0029] Example 2 A high-temperature sterilized modified milk, which is different from Example 1 in that the raw materials and their dosages are shown in Table 1. Among them, the protective agent is yeast β-glucan, β-cyclodextrin, lecithin, carboxymethyl cellulose sodium and tea polyphenol with a mass ratio of 10:7:2:1:0.1, the compound stabilizer is gellan gum, xanthan gum and light calcium carbonate with a mass ratio of 3:1:4, and the saccharide substance is stevioside and mogroside with a mass ratio of 1:1; The preparation method of the above high-temperature sterilized modified milk includes the following steps: S1: Preparation of microcapsules of phytosterol esters and DHA algal oil (1) Dissolve yeast β-glucan in water at (80 ± 2) °C and stir until completely dissolved to obtain a first solution with a concentration of 8%; (2) Dissolve β-cyclodextrin in water at (65 ± 2) °C and stir until completely dissolved to obtain a second solution with a concentration of 10%; (3) Mix the first solution and the second solution, add lecithin, carboxymethyl cellulose sodium and tea polyphenol, and stir evenly to obtain the wall material solution; (4) Heat and melt phytosterol esters and DHA algal oil at (55 ± 2) °C and stir evenly to obtain the core material solution; (5) Add the core material solution to the wall material solution and stir evenly. Shear at 10000 rpm for 2 min, then homogenize at 25 MPa first and then at 45 MPa, and the homogenization temperature is 60 °C for both times. Then adjust the pH to 3.5 ± 0.5 to obtain the microcapsule emulsion; (6) Spray-dry the microcapsule emulsion. The conditions for spray drying are: the feeding temperature is 70 °C, the inlet air temperature is 140 °C, and the hot air flow rate is 0.5 m 3 / min, the average feeding rate is 4 mL / min, and microcapsules of phytosterol esters and DHA algal oil are obtained; S2: Heat the milk to (45 ± 5) °C, and while stirring, add the microcapsules of phytosterol esters and DHA algal oil, the compound stabilizer, the saccharide substance and inulin. Then, homogenize at 30 MPa first and then at 40 MPa, and the homogenization temperature is 60 °C for both times to obtain the homogenized liquid; S3: High-temperature sterilize the homogenized liquid for 4 s at (137 ± 2) °C, and then can it after cooling to obtain the product.

[0030] Example 3 A high-temperature sterilized formulated milk, different from Example 1 in that the raw materials and their dosages are shown in Table 1. Among them, the protective agent is yeast β-glucan, β-cyclodextrin, lecithin, carboxymethyl cellulose sodium and tea polyphenol with a mass ratio of 15:10:4:1:0.5, the composite stabilizer is gellan gum, xanthan gum and light calcium with a mass ratio of 3:2:6, the saccharide substance is sucralose, and the other steps are the same as those in Example 1.

[0031] Example 4 A high-temperature sterilized formulated milk, different from Example 1 in that the raw materials and their dosages are shown in Table 1. Among them, the protective agent is yeast β-glucan, β-cyclodextrin, lecithin, carboxymethyl cellulose sodium and tea polyphenol with a mass ratio of 14:9:3:1:0.2, the composite stabilizer is gellan gum, xanthan gum and light calcium with a mass ratio of 2:1:5, and the other steps are the same as those in Example 1.

[0032] Example 5 A high-temperature sterilized formulated milk, different from Example 1 in that the protective agent in the raw materials is yeast β-glucan, β-cyclodextrin, lecithin, carboxymethyl cellulose sodium and tea polyphenol with a mass ratio of 7:13:3:1:0.3, and the other steps are the same as those in Example 1.

[0033] Example 6 A high-temperature sterilized formulated milk, different from Example 1 in that light calcium is not added, and light calcium in the raw material composite stabilizer is replaced with an equal mass of cow milk, and the other steps are the same as those in Example 1.

[0034] Comparative Example Comparative Example 1 A high-temperature sterilized formulated milk, different from Example 1 in that yeast β-glucan is not added, and yeast β-glucan in the raw material protective agent is replaced with an equal mass of β-cyclodextrin, and the other steps are the same as those in Example 1.

[0035] Comparative Example 2 A high-temperature sterilized formulated milk, different from Example 1 in that β-cyclodextrin is not added, and β-cyclodextrin in the raw material protective agent is replaced with an equal mass of yeast β-glucan, and the other steps are the same as those in Example 1.

[0036] Comparative Example 3 A high-temperature sterilized formulated milk, different from Example 1 in that tea polyphenol is not added, and tea polyphenol in the raw material protective agent is replaced with an equal mass of cow milk, and the other steps are the same as those in Example 1.

[0037] Comparative Example 4 A high-temperature sterilized formulated milk, which is different from that of Example 1 in that no protective agent is added, and the protective agent in the raw materials is replaced with the same mass of cow milk. Its preparation method includes the following steps: S1: Heat the cow milk to (45±5)°C, add phytosterol esters, DHA algal oil, compound stabilizer, saccharide substances and inulin while stirring, then perform homogenization treatment at 20 MPa first, and then at 40 MPa. The homogenization temperature is 80°C for both times to obtain a homogenized liquid; S2: Perform high-temperature sterilization on the homogenized liquid at (137±2)°C for 6 s, and can it after cooling.

[0038] Comparative Example 5 A high-temperature sterilized formulated milk, which is different from that of Example 1 in that its preparation method includes the following steps: S1: Heat the cow milk to (45±5)°C, add phytosterol esters, DHA algal oil, protective agent, compound stabilizer, saccharide substances and inulin while stirring, then perform homogenization treatment at 20 MPa first, and then at 40 MPa. The homogenization temperature is 80°C for both times to obtain a homogenized liquid; S2: Perform high-temperature sterilization on the homogenized liquid at (137±2)°C for 6 s, and can it after cooling.

[0039] Comparative Example 6 A high-temperature sterilized formulated milk, which is different from that of Example 1 in that no compound stabilizer is added, and the compound stabilizer in the raw materials is replaced with the same mass of cow milk, and other steps are the same as those of Example 1.

[0040] Performance detection test Perform performance detection tests on the stability and taste and flavor of a high-temperature sterilized formulated milk obtained in Examples 1-6 and Comparative Examples 1-6.

[0041] 1. Stability detection: Place the high-temperature sterilized formulated milk obtained in Examples 1-6 and Comparative Examples 1-6 in transparent glass bottles respectively, and place them at room temperature for 1-6 months. Each month, detect the floating situation of fat and sterol ester components, the precipitation situation of substances such as protein, and the water separation situation of the formulated milk to be tested. Without shaking, use a vernier caliper to measure the floating thickness of the fat and sterol ester components on the upper layer of the formulated milk, observe whether there is a water separation phenomenon, and then centrifuge the formulated milk to be tested to calculate the precipitation rate of protein. Each group of tests is carried out 3 times, and the average value of the 3 test results is taken as the final result and the final result is recorded in Table 2; 2. Taste and flavor detection: Select 10 evaluators in the food industry and evaluate and score the taste and flavor of a high-temperature sterilized modulated milk obtained in Examples 1-6 and Comparative Examples 1-6 through sensory evaluation. The score range is 1-10 points, with a minimum interval of 0.5. Take the average value of the scores of the 10 evaluators as the final value of each group of test results and record the final value in Table 2. The scoring criteria are as follows: 8 < score ≤ 10, the taste is sweet and smooth, has a good flavor of modulated milk, and has no other bad tastes; 5 < score ≤ 8, the taste is relatively sweet and smooth, has a good flavor of modulated milk, but has a slight bitter taste and other strange tastes, which can be accepted; 1 ≤ score ≤ 5, the taste is smooth, still has the flavor of modulated milk, but has an obvious bitter taste and other strange tastes.

[0042] Table 2 It can be seen from the performance test results in Table 2 that a high-temperature sterilized modulated milk of the present application has excellent stability. Each raw material component can be evenly dispersed in the dairy product system, and there is almost no phenomenon of uneven stratification of product components caused by the floating of hydrophobic fat-like and sterol ester components or protein precipitation within half a year, and it has a long shelf life.

[0043] It can be seen from the performance test results of Examples 1-4 and Comparative Examples 4-5 that the present application uses phytosterol esters and DHA algal oil as core materials, yeast β-glucan as the main wall material, and β-cyclodextrin as the auxiliary wall material to prepare microcapsule-embedded particles and then carry out a high-temperature sterilization process to prepare modulated milk, effectively reducing the isomerization or activity loss of the core materials caused by high temperature in the high-temperature sterilization preparation process, improving the high-temperature retention rate and suspension stability of phytosterol esters and DHA algal oil, reducing obvious bitter tastes and other strange tastes generated by the high-temperature isomerization of sterol esters, and effectively extending the shelf life of the product.

[0044] However, directly using yeast β-glucan and β-cyclodextrin as raw materials and mixing them with phytosterol esters and DHA algal oil for preparing high-temperature sterilized modulated milk can, to a certain extent, improve the stability of the system, but the heat-resistant protection effect of yeast β-glucan and β-cyclodextrin on phytosterol esters and DHA algal oil at high temperature is far less than that of the microcapsule-structured embedded particles.

[0045] According to the performance test results of Example 1, Example 5 and Comparative Examples 1-2, it can be seen that when yeast β-glucan and β-cyclodextrin are used as wall materials to prepare microcapsule-encapsulated particles of plant sterol esters and DHA algae oil, when β-cyclodextrin is used as the main wall material raw material, the protection effect on the core material is not as significant as that of yeast β-glucan. This is because for the modulated milk prepared by high-temperature sterilization process, yeast β-glucan plays a major role in high-temperature protection of the core material, and β-cyclodextrin assists in promoting the suspension stability of the microcapsules in the emulsion system. The decreased stability of the group system without adding β-cyclodextrin is caused by the poor compatibility between the microcapsules and the modulated milk system.

[0046] Only when yeast β-glucan is used as the main wall material, the microcapsule can achieve the best high-temperature protection effect on the core material, reduce the loss of nutritional value and the impact on taste and flavor caused by the destruction or isomerization of the core material during the high-temperature sterilization process, ensure the stability and efficacy of the formula milk system, and extend the shelf life.

[0047] According to the performance test results of Example 1 and Comparative Example 3, it can be seen that the trace use of tea polyphenols can not only improve the long-term stability of the formula milk system, but also help to improve the taste and flavor. This is because tea polyphenols, as an antioxidant, further enhance the antioxidant properties of the microcapsule structure under high-temperature sterilization conditions, inhibit the oxidative decomposition of the core material during the high-temperature sterilization process, reduce the bitter taste caused by the possible oxidation or isomerization of plant sterol esters, improve the taste and flavor of the formula milk, effectively ensure the bioavailability of the core material, and at the same time extend the shelf life of the high-temperature sterilized formula milk.

[0048] According to the performance test results of Examples 1-4 and Comparative Example 6, it can be seen that the composite stabilizer can not only promote the stability of protein and fat in cow's milk, but also further promote the stability of microcapsules in the formula milk system, effectively reduce the problems of sterol esters and fat components floating up, protein denaturation and precipitation of other components that are prone to occur during the high-temperature sterilization and storage process of high-temperature sterilized formula milk, thereby ensuring the nutritional value, taste and flavor of the product and extending the shelf life.

[0049] According to the performance test results of Example 1 and Example 6, it can be seen that the high-temperature sterilized formula milk prepared in combination with a composite stabilizer containing light calcium further alleviates the problems of product stratification and uneven texture compared to the system without adding light calcium. This is because light calcium can combine with milk protein in the formula milk to form a denser micellar network, and further inhibit the migration of hydrophobic substances such as milk fat in the formula milk through physical barrier methods, thereby overcoming the problems of product stratification and uneven texture caused by the floating of hydrophobic or fat components or protein precipitation in the formula milk during storage, effectively extending the shelf life of the product, and ensuring the cholesterol-lowering ability, taste, flavor and nutrition of the high-temperature sterilized formula milk.

[0050] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment that do not contribute creatively as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A high temperature sterilized formulated milk, characterized in that: According to the percentage by mass, it includes 0.21-0.57% of phytosterol ester, 0.05-0.35% of DHA algae oil, 1-2.5% of protective agent, 0.05-0.1% of composite stabilizer, 3-7% of sugar substance and 0.5-1.5% of inulin, and the balance is raw milk; The protective agent comprises yeast beta-glucan, beta-cyclodextrin, lecithin and tea polyphenols.

2. The high temperature sterilized formula milk according to claim 1, characterized in that: The protective agent comprises yeast beta-glucan, beta-cyclodextrin, lecithin and tea polyphenols in a mass ratio of (10-15):(7-10):(2-4):(0.1-0.5).

3. The high temperature sterilized formula milk according to claim 1, characterized in that: The composite stabilizer comprises gellan gum, xanthan gum and light calcium in a mass ratio of (2-3):(1-2):(3-6).

4. The high temperature sterilized formula milk according to claim 1, characterized in that: The raw milk is selected from any one of cow's milk or goat's milk.

5. The high temperature sterilized formula milk according to claim 1, characterized in that: The sugar substance is selected from any one or more combinations of sucralose, steviol glycosides, mogrosides and galacto-oligosaccharides.

6. The process for preparing a high temperature sterilized modulated milk according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1: dissolving yeast β-glucan in water and stirring until completely dissolved to obtain a first solution, dissolving β-cyclodextrin in water and stirring until completely dissolved to obtain a second solution, mixing the first solution with the second solution, adding lecithin and tea polyphenols, and stirring evenly to obtain a wall material liquid; The phytosterol ester and DHA algae oil are heated, melted and stirred evenly to obtain a core material liquid, the core material liquid is added to the wall material liquid, stirred, sheared and homogenized to obtain a microcapsule emulsion, and then spray-dried to obtain microcapsules of the phytosterol ester and DHA algae oil; S2: heating and stirring the raw milk, adding microcapsules of phytosterol esters and DHA algae oil, a composite stabilizer, a carbohydrate and inulin, and then homogenizing to obtain a homogenous liquid; S3: sterilize the homogenized liquid at (137±2)°C for 4-6s, and then can it after cooling.

7. The process for preparing high temperature sterilized modulated milk according to claim 6, characterized in that: The conditions for spray drying the microcapsule emulsion in step S1 are: feed temperature of 60-70°C, air inlet temperature of 120-140°C, hot air flow rate of 0.5m 3 / min, and the average feed rate is 4mL / min.

8. The process for preparing high temperature sterilized modulated milk according to claim 6, characterized in that: The conditions for the homogenization treatment in step S3 are: a homogenization pressure of 20-40 MPa and a homogenization temperature of 60-80°C.

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