High-protein high-energy nutrient solution and preparation method and application thereof

Abstract

This invention discloses a high-protein, high-energy nutrient solution, its preparation method, and its application, belonging to the field of nutritional food processing technology. Its raw materials include: concentrated milk protein, concentrated whey protein, casein, rapeseed oil, coconut oil, collagen peptides, fish oil extract, flaxseed oil, medium-chain triglycerides, maltodextrin, polydextrose, sodium caseinate, phospholipids, complex vitamins, complex minerals, taurine, carrageenan, gellan gum, sweeteners, pH adjusters, edible flavorings, and water. This invention, through fermentation and microencapsulation, significantly improves the physical and oxidative stability of the multi-protein, multi-oil system, effectively masks fishy odor, and solves the problems of product stability, flavor, and nutrient retention.

Description

Technical Field

[0001] This invention belongs to the field of nutritional food processing technology, specifically relating to a high-protein, high-energy nutrient solution, its preparation method, and its application. Background Technology

[0002] High-protein, high-energy nutritional liquids are a type of special dietary product designed for individuals with restricted food intake, digestive and absorption disorders, metabolic disorders, or specific disease states, as well as those engaged in high-intensity exercise or recovering from surgery, who require high-protein, high-energy nutrition. These products must provide sufficient high-quality protein, a combination of fats that provide rapid and sustained energy within a limited volume, and a comprehensive and balanced intake of vitamins and minerals.

[0003] There are already various high-protein nutrient solutions available in the current technology, but they generally suffer from the following problems: First, the coexistence of high-content, multi-source proteins and various types of oils in a single system makes them prone to stability issues such as precipitation, stratification, and lipid oxidation, resulting in a short shelf life. Second, in order to mask undesirable flavors (such as fish oil, mineral, or hydrolyzed protein flavors) or achieve emulsification stability, it is often necessary to add a large amount of stabilizers, emulsifiers, or flavoring agents, resulting in a heavy, powdery, or off-flavor taste. Third, traditional heat treatment sterilization processes (such as pasteurization) severely damage heat-sensitive nutrients (such as vitamins and polyunsaturated fatty acids), while ultra-high temperature (UHT) sterilization, although able to preserve nutrients, requires extremely high emulsification stability of the system.

[0004] Therefore, developing a high-protein, high-energy nutrient solution that combines excellent physical stability, good flavor and taste, high nutrient density, and minimal nutrient loss remains a technical challenge that urgently needs to be addressed in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-protein, high-energy nutrient solution, its preparation method, and its applications. This invention retains the flavor substances and metabolites produced during fermentation in the final product. Furthermore, by combining post-fermentation microencapsulation, colloidal network regulation, and UHT sterilization, it solves the challenges of stability, mouthfeel, nutrient retention, and flavor quality in complex systems with multiple proteins, fats, and functional components.

[0006] Terminology Explanation: Unless otherwise defined, all technical terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this subject matter pertains. Unless otherwise stated, all patents, patent inventions, and disclosures cited throughout this document are incorporated herein by reference in their entirety. Where multiple definitions exist for terms herein, the definitions provided in this chapter shall prevail.

[0007] It should be understood that the above brief description and the following detailed description are exemplary and for illustrative purposes only, and do not limit the subject matter of the invention in any way. In this invention, the singular is used in conjunction with the plural unless otherwise specifically stated. It should also be noted that, unless otherwise stated, the use of “or” or “or” means “and / or”. Furthermore, the use of the term “comprising” and other forms such as “including,” “containing,” and “contains” are not limiting.

[0008] Unless specifically defined herein, the use of all commercially available products herein employs standard techniques. For example, it may be carried out using the manufacturer's instructions for use with the kit, or in accordance with methods known in the art or the description of this invention. The techniques and methods described herein can generally be implemented according to conventional methods well known in the art, based on the descriptions in the various summary and more specific documents cited and discussed in this specification.

[0009] The terms “optional / arbitrary” or “optionally / arbitrarily” mean that the event or situation described below may or may not occur, including both the occurrence and non-occurrence of the event or situation.

[0010] In a first aspect, the present invention provides a method for preparing a high-protein, high-energy nutrient solution, comprising the following steps: (1) Mix a portion of concentrated milk protein, a portion of concentrated whey protein and a portion of casein with maltodextrin, polydextrose, sodium caseinate and water, sterilize and cool to obtain a protein-carbohydrate matrix solution. (2) Inoculate the protein-carbohydrate matrix liquid with a compound fermentation agent, ferment, sterilize, and cool to obtain a fermentation base liquid; the compound fermentation agent is composed of Lactobacillus plantarum, Streptococcus thermophilus and Saccharomyces boulardii in a mass ratio of 2-5:1-3:0.5-2; (3) Mix low-erucic acid rapeseed oil, coconut oil, flaxseed oil and a portion of medium-chain triglycerides to obtain a mixed vegetable oil; mix fish oil extract with phospholipids and then add it to the mixed vegetable oil to obtain a composite oil phase; dissolve fat-soluble complex vitamins in the remaining medium-chain triglycerides and add them to the composite oil phase to obtain a fat-soluble premix; (4) Mix the remaining concentrated milk protein, concentrated whey protein and casein with collagen peptides, taurine, water-soluble complex vitamins, complex minerals and water to obtain a water-soluble functional premix. (5) Mix carrageenan and gellan gum with water to obtain a colloidal solution; (6) Add the colloidal solution to the fermentation base liquid, then add the fat-soluble premix and the water-soluble functional premix in sequence, mix, then add sweetener, pH adjuster, edible flavor and water, deaerate, homogenize, sterilize, and fill to obtain the product.

[0011] The three microorganisms, *Lactobacillus plantarum*, *Streptococcus thermophilus*, and *Saccharomyces boulardii*, exhibit synergistic effects: *Lactobacillus plantarum* primarily produces lactic acid and bacteriocins, imparting a mellow sour taste and natural preservative properties to the product; *Streptococcus thermophilus* produces characteristic fermentation flavor compounds such as acetaldehyde and diacetyl, enhancing the product's milky aroma and richness; and *Saccharomyces boulardii* produces aromatic alcohols and esters, further improving the complexity and smoothness of the flavor. The complex flavor profile produced by these three synergistically effectively masks any unpleasant odors from subsequently added fish oil, minerals, and proteins.

[0012] In addition, during fermentation, lactic acid bacteria metabolize carbohydrates to produce extracellular polysaccharides (EPS). These EPS form a complex colloidal network with added carrageenan and gellan gum in subsequent steps, enhancing the system's suspension stability and smoothness. Because EPS is generated in a pure matrix, it is protected from adsorption / destruction by minerals or oils, ensuring both its yield and molecular weight.

[0013] Preferably, the raw materials of the high-protein, high-energy nutrient solution, by weight, include: 30-60 parts concentrated milk protein, 10-30 parts concentrated whey protein, 5-15 parts casein, 15-30 parts rapeseed oil, 5-15 parts coconut oil, 5-20 parts collagen peptides, 0.05-0.3 parts fish oil extract, 2-8 parts flaxseed oil, 5-20 parts medium-chain triglycerides, 50-100 parts maltodextrin, and 10- 30 parts, sodium caseinate 2-8 parts, phospholipids 1-5 parts, fat-soluble vitamins 0.3-1.2 parts, water-soluble complex vitamins 0.2-0.8 parts, complex minerals 1-5 parts, taurine 0.1-0.8 parts, carrageenan 0.2-1.0 parts, gellan gum 0.1-0.5 parts, sweetener 0.01-0.2 parts, pH adjuster 0.1-0.5 parts, edible flavoring 0.5-2 parts, and water 700-850 parts.

[0014] More preferably, in step (1), the partial concentrated milk protein, partial concentrated whey protein, and partial casein constitute 50%-70%, 50%-70%, and 50%-70% of the total formula amount, respectively; the amount of water used is 40%-50% of the total water amount of the formula; the sterilization temperature is 90-95℃, the sterilization time is 10-15 min; and the temperature is cooled to 35-38℃. The mixing conditions are: stirring at 600-800 r / min for 20-30 min, and the water temperature is 45-55℃.

[0015] More preferably, in step (2), the inoculation amount of the compound fermentation agent is 0.1%-0.5% of the mass of the protein-carbohydrate matrix liquid, the fermentation temperature is 35-38℃, the fermentation time is 6-16h, the sterilization temperature is 85-90℃, the sterilization time is 5-10 min, and the temperature is cooled to 45-50℃.

[0016] More preferably, the temperature of the mixed vegetable oil in step (3) is 40-50°C; the portion of medium-chain triglycerides accounts for 70%-90% of the total amount of the formula, and the remaining medium-chain triglycerides account for 10%-30% of the total amount of the formula.

[0017] More preferably, in step (4), the remaining concentrated milk protein, concentrated whey protein and casein account for 30%-50%, 30%-50% and 30%-50% of the total amount of the formula, respectively, and the amount of water used is 15%-20% of the total amount of water in the formula, and the temperature is 45-55℃; in step (5), the amount of water used is 5%-8% of the total amount of water in the formula, the temperature is 75-85℃, and the mixture is cooled to 45-55℃.

[0018] Preferably, in step (6), the degassing vacuum degree is -0.06~-0.09MPa and the time is 10-15min; the homogenization pressure is 20-30MPa; and the sterilization temperature is 135-140℃ and the time is 3-8s.

[0019] Preferably, the fat-soluble complex vitamin is selected from one or more of vitamin A, vitamin D, and vitamin E; the water-soluble complex vitamin is selected from one or more of vitamin B1, vitamin B2, vitamin B6, vitamin B12, niacin, folic acid, and pantothenic acid; the complex mineral is selected from one or more of magnesium oxide, ferric pyrophosphate, zinc sulfate, and sodium selenite; the sweetener is sucralose and / or steviol glycosides; and the pH adjuster is sodium carbonate and / or sodium citrate.

[0020] Secondly, the present invention provides a high-protein, high-energy nutrient solution prepared by the above-mentioned preparation method.

[0021] Thirdly, the present invention provides the application of the high-protein, high-energy nutrient solution prepared by the above-described method in the preparation of products that provide nutritional support.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) In this invention, some proteins and carbohydrates are subjected to compound fermentation treatment with lactic acid bacteria and yeast. Fermentation not only gives the product a natural, mild and pure fermented flavor, but also effectively masks the unpleasant odors brought by fish oil, minerals and proteins themselves, significantly improving the product's taste acceptance; at the same time, the organic acids and bacteriocins produced by fermentation have natural preservative and synergistic effects, and can partially degrade large protein molecules into small peptides and amino acids, making them easier to digest and absorb.

[0023] (2) This invention employs a "segmented emulsification and microencapsulation" technology: phospholipids and sodium caseinate are used to pre-emulsify the highly oxidizable fish oil extract and disperse it in a stable composite vegetable oil phase; simultaneously, fat-soluble vitamins are dissolved in medium-chain triglycerides (MCT) to form an oil core. This multi-layered microencapsulation structure significantly improves the oxidative stability of EPA / DHA and fat-soluble vitamins in fish oil during subsequent UHT sterilization and shelf life. Detailed Implementation

[0024] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection claimed by the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and such changes should also fall within the scope of protection claimed by the present invention.

[0025] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all instruments, devices, equipment, reagents, products, etc., used in the embodiments of the present invention are obtained through conventional commercial means.

[0026] Lactobacillus plantarum (10 billion CFU / g, catalog number PG-LPZ131), Streptococcus thermophilus (10 billion CFU / g, catalog number PG-STS302), and Saccharomyces boulardii (10 billion CFU / g, catalog number PG-SBB19) were all purchased from Shandong Pingao Pharmaceutical Co., Ltd.

[0027] Concentrated milk protein (model MPC80), concentrated whey protein (model WPC80), and sodium caseinate were purchased from Fonterra, New Zealand; casein (model MCI) was purchased from Leitup, Spain; collagen peptides (model XB) were purchased from Jialida; low-erucic acid rapeseed oil (refined), coconut oil (Jinli brand), and medium-chain triglycerides were purchased from Yihai Kerry Arawana Food Group Co., Ltd.; fish oil extract (DHA≥12.5%) and flaxseed oil were purchased from Zhonghe Jianyuan Biotechnology Co., Ltd.; maltodextrin (model MD19) was purchased from Roquette (China) Nutritional Food Co., Ltd.; polydextrose was purchased from Litesse, UK; phospholipids were purchased from Cargill; carrageenan and gellan gum were purchased from Spico; and edible flavoring (fruit juice flavoring) was purchased from Firmenich Flavors (China) Co., Ltd.

[0028] Example 1 A high-protein, high-energy nutrient solution, by weight, comprises the following ingredients: 45 parts concentrated milk protein, 20 parts concentrated whey protein, 10 parts casein, 20 parts low-erucic acid rapeseed oil, 10 parts coconut oil, 12 parts collagen peptides, 0.2 parts fish oil extract, 5 parts flaxseed oil, 12 parts medium-chain triglycerides, 80 parts maltodextrin, 20 parts polydextrose, 5 parts sodium caseinate, 3 parts phospholipids, and 1 part complex vitamin (fat-soluble vitamins: vitamin A 0.1 part, vitamin D 0.01 part, vitamin E 0.49 part; water-soluble vitamins: vitamin B1 0.02 part, vitamin B2 0.02 part, vitamin B6 0.02 part, vitamin B12 0.005 part, niacin 0.2 part, folic acid 0.005 part, pantothenic acid 0.1 part, vitamin C). 0.8 parts of biotin, 2.5 parts of compound minerals (1.2 parts of magnesium oxide, 0.5 parts of ferric pyrophosphate, 0.3 parts of zinc sulfate, 0.001 parts of sodium selenite), 0.5 parts of taurine, 0.5 parts of carrageenan, 0.2 parts of gellan gum, 0.05 parts of sucralose, 0.02 parts of steviol glycosides, 0.3 parts of sodium carbonate, 1.0 part of edible flavoring, and 800 parts of water.

[0029] The preparation method is as follows: (1) Take 50% water and heat it to 50°C. Then add 60% concentrated milk protein, 60% concentrated whey protein, 60% casein, maltodextrin, polydextrose and sodium caseinate in sequence. Stir at 700 r / min for 25 min, sterilize at 92°C for 12 min, and cool to 37°C to obtain protein-carbohydrate matrix solution. (2) Inoculate the protein-carbohydrate matrix liquid with 0.3% of the compound fermentation agent (Lactobacillus plantarum: Streptococcus thermophilus: Saccharomyces boulardii = 3:2:1), ferment at 37℃ for 12h, then sterilize at 88℃ for 8min, and cool to 48℃ to obtain the fermentation base liquid; (3) Low erucic acid rapeseed oil, coconut oil, flaxseed oil and 80% medium chain triglycerides are mixed at 45°C to obtain a mixed vegetable oil; fish oil extract and phospholipids are mixed under nitrogen protection and then added to the mixed vegetable oil to obtain a composite oil phase; fat-soluble complex vitamins are dissolved in 20% medium chain triglycerides and added to the composite oil phase to obtain a fat-soluble premix; (4) Take 20% water and heat it to 50°C. Add the remaining concentrated milk protein, concentrated whey protein and casein, as well as collagen peptides, taurine, water-soluble complex vitamins and complex minerals. Stir to dissolve and obtain water-soluble functional premix. (5) Take 10% water and heat it to 80°C to dissolve carrageenan and gellan gum, then cool it to 50°C to obtain a colloidal solution; (6) Add the colloidal solution to the fermentation base liquid, stir, add the fat-soluble premix and the water-soluble functional premix in sequence, and mix evenly; finally add sucralose, steviol glycosides, sodium carbonate, edible flavor and the remaining water, degas at -0.08MPa for 12min, then homogenize at 25MPa pressure, and then sterilize at 137℃ for 5s, and fill to obtain the product.

[0030] Example 2 A high-protein, high-energy nutrient solution, by weight, comprises the following ingredients: 30 parts concentrated milk protein, 30 parts concentrated whey protein, 5 parts casein, 15 parts low-erucic acid rapeseed oil, 15 parts coconut oil, 5 parts collagen peptides, 0.3 parts fish oil extract, 2 parts flaxseed oil, 20 parts medium-chain triglycerides, 50 parts maltodextrin, 30 parts polydextrose, 2 parts sodium caseinate, 5 parts phospholipids, and 1 part complex vitamin (fat-soluble vitamins: vitamin A 0.1 part, vitamin D 0.01 part, vitamin E 0.49 part; water-soluble vitamins: vitamin B1 0.02 part, vitamin B2 0.02 part, vitamin B6 0.02 part, vitamin B12 0.005 part, niacin 0.2 part, folic acid 0.005 part, pantothenic acid 0.1 part, vitamin C). 0.8 parts of biotin, 2.5 parts of compound minerals (1.2 parts of magnesium oxide, 0.5 parts of ferric pyrophosphate, 0.3 parts of zinc sulfate, 0.001 parts of sodium selenite), 0.1 parts of taurine, 1.0 part of carrageenan, 0.1 part of gellan gum, 0.01 parts of sucralose, 0.5 parts of sodium carbonate, 0.5 parts of edible flavoring, and 850 parts of water.

[0031] The preparation method is as follows: (1) Take 45% water and heat it to 45°C. Then add 50% concentrated milk protein, 50% concentrated whey protein, 50% casein, maltodextrin, polydextrose and sodium caseinate in sequence. Stir at 600r / min for 30 min, sterilize at 90°C for 15 min, and cool to 35°C to obtain protein-carbohydrate matrix solution. (2) Inoculate the protein-carbohydrate matrix liquid with 0.2% of the compound fermentation agent (Lactobacillus plantarum: Streptococcus thermophilus: Saccharomyces boulardii = 3:2:1), ferment at 35℃ for 15h, then sterilize at 85℃ for 10min, cool to 45℃ to obtain the fermentation base liquid; (3) Low erucic acid rapeseed oil, coconut oil, flaxseed oil and 70% medium chain triglycerides are mixed at 40°C to obtain a mixed vegetable oil; fish oil extract and phospholipids are mixed under nitrogen protection and then added to the mixed vegetable oil to obtain a composite oil phase; fat-soluble complex vitamins are dissolved in 30% medium chain triglycerides and added to the composite oil phase to obtain a fat-soluble premix; (4) Take 15% water and heat it to 45°C. Add the remaining concentrated milk protein, concentrated whey protein and casein, as well as collagen peptides, taurine, water-soluble complex vitamins and complex minerals. Stir to dissolve and obtain water-soluble functional premix. (5) Take 10% water and heat it to 75°C to dissolve carrageenan and gellan gum, then cool it to 45°C to obtain a colloidal solution; (6) Add the colloidal solution to the fermentation base liquid, stir, add the fat-soluble premix and the water-soluble functional premix in sequence, mix evenly; finally add sucralose, sodium carbonate, edible flavor and the remaining water, degas at -0.06MPa for 15 min, then homogenize at 20MPa pressure, then sterilize at 135℃ for 5s, and fill to obtain the product.

[0032] Example 3 A high-protein, high-energy nutrient solution, by weight, comprises the following ingredients: 60 parts concentrated milk protein, 10 parts concentrated whey protein, 15 parts casein, 30 parts low-erucic acid rapeseed oil, 5 parts coconut oil, 20 parts collagen peptides, 0.05 parts fish oil extract, 8 parts flaxseed oil, 5 parts medium-chain triglycerides, 100 parts maltodextrin, 10 parts polydextrose, 8 parts sodium caseinate, 1 part phospholipid, and 1 part complex vitamins (fat-soluble vitamins: vitamin A 0.1 part, vitamin D 0.01 part, vitamin E 0.49 part; water-soluble vitamins: vitamin B1 0.02 part, vitamin B2 0.02 part, vitamin B6 0.02 part, vitamin B12 0.005 part, niacin 0.2 part, folic acid 0.005 part, pantothenic acid 0.1 part, vitamin C). 0.8 parts of taurine, 0.005 parts of biotin, 2.5 parts of compound minerals (1.2 parts of magnesium oxide, 0.5 parts of ferric pyrophosphate, 0.3 parts of zinc sulfate, 0.001 parts of sodium selenite), 0.8 parts of taurine, 0.2 parts of carrageenan, 0.5 parts of gellan gum, 0.1 parts of steviol glycosides, 0.1 parts of sodium citrate, 2 parts of edible flavoring, and 700 parts of water.

[0033] The preparation method is as follows: (1) Take 50% water and heat it to 55°C. Then add 70% concentrated milk protein, 70% concentrated whey protein, 70% casein, maltodextrin, polydextrose and sodium caseinate in sequence. Stir at 800 r / min for 20 min, sterilize at 95°C for 10 min, and cool to 38°C to obtain protein-carbohydrate matrix solution. (2) Inoculate the protein-carbohydrate matrix liquid with a compound fermentation agent (Lactobacillus plantarum: Streptococcus thermophilus: Saccharomyces boulardii = 3:2:1) at 0.4% of its mass, ferment at 38℃ for 7h, then sterilize at 90℃ for 5min, cool to 50℃ to obtain the fermentation base liquid; (3) Low erucic acid rapeseed oil, coconut oil, flaxseed oil and 90% medium chain triglycerides are mixed at 50°C to obtain a mixed vegetable oil; fish oil extract and phospholipids are mixed under nitrogen protection and then added to the mixed vegetable oil to obtain a composite oil phase; fat-soluble complex vitamins are dissolved in 10% medium chain triglycerides and added to the composite oil phase to obtain a fat-soluble premix; (4) Take 20% water and heat it to 55°C. Add the remaining concentrated milk protein, concentrated whey protein and casein, as well as collagen peptides, taurine, water-soluble complex vitamins and complex minerals. Stir to dissolve and obtain water-soluble functional premix. (5) Take 5% water and heat it to 85°C to dissolve carrageenan and gellan gum, then cool it to 55°C to obtain a colloidal solution; (6) Add the colloidal solution to the fermentation base liquid, stir, add the fat-soluble premix and the water-soluble functional premix in sequence, mix evenly; finally add steviol glycosides, sodium citrate, edible flavor and the remaining water, degas at -0.09MPa for 10min, then homogenize at 30MPa pressure, then sterilize at 140℃ for 5s, and fill to obtain the product.

[0034] Comparative Example 1 The only difference between this comparative example and Example 1 is that the fermentation process in step (2) is omitted. Step (6) is as follows: the colloidal solution is added to the protein-carbohydrate matrix solution and stirred. Then, the fat-soluble premix and the water-soluble functional premix are added in sequence and mixed evenly. Finally, sucralose, steviol glycosides, sodium carbonate, edible flavoring and the remaining water are added. The mixture is degassed at -0.08 MPa for 12 min, then homogenized at 25 MPa pressure, and then sterilized at 137°C for 5 s. The mixture is then filled into containers to obtain the final product.

[0035] The other raw materials and steps are the same as in Example 1.

[0036] Comparative Example 2 The only difference between this comparative example and Example 1 is step (3), in which microencapsulation pretreatment was not used. Specifically, low-erucic acid rapeseed oil, coconut oil, flaxseed oil, medium-chain triglycerides, fish oil extract, phospholipids, and fat-soluble vitamins were directly mixed to obtain a fat-soluble premix. Other raw materials and steps were the same as in Example 1.

[0037] Comparative Example 3 The only difference between this comparative example and Example 1 is the preparation method: the microencapsulation step is moved before the fermentation step. The specific steps are as follows: (1) Take 50% water and heat it to 50°C. Then add 60% concentrated milk protein, 60% concentrated whey protein, 60% casein, maltodextrin, polydextrose and sodium caseinate in sequence. Stir at 700r / min for 25 min, sterilize at 92°C for 12 min, and cool to 45°C to obtain protein-carbohydrate matrix solution. (2) Low erucic acid rapeseed oil, coconut oil, flaxseed oil and 80% medium chain triglycerides are mixed at 45°C to obtain mixed vegetable oil; fish oil extract and phospholipids are mixed under nitrogen protection and added to the mixed vegetable oil to obtain a composite oil phase; fat-soluble complex vitamins are dissolved in 20% medium chain triglycerides and added to the composite oil phase to obtain a fat-soluble premix; (3) Add the fat-soluble premix to the protein-carbohydrate matrix solution and stir at 700 r / min for 15 min to obtain the fermentation matrix; inoculate the fermentation matrix with 0.3% of the compound fermentation agent (Lactobacillus plantarum: Streptococcus thermophilus: Saccharomyces boulardii = 3:2:1) and ferment at 37℃ for 12 h. After fermentation, sterilize at 88℃ for 8 min and cool to 48℃ to obtain the fermentation liquid; (4) Take 20% water and heat it to 50°C. Add the remaining concentrated milk protein, concentrated whey protein and casein, as well as collagen peptides, taurine, water-soluble complex vitamins and complex minerals. Stir to dissolve and obtain water-soluble functional premix. (5) Take 10% water and heat it to 80°C to dissolve carrageenan and gellan gum, then cool it to 50°C to obtain a colloidal solution; (6) Add the colloidal solution to the fermentation broth, stir, add the water-soluble functional premix, mix evenly, and finally add sucralose, sodium carbonate, edible flavoring and the remaining water. Degas at -0.06MPa for 15 min, then homogenize at 20MPa pressure, and then sterilize at 135℃ for 5 s. Fill into the container to obtain the product.

[0038] Comparative Example 4 The difference between this comparative example and Example 1 is that all raw materials are mixed, fermented, homogenized, and sterilized at once. The specific steps are as follows: (1) Heat the total amount of water in the formula to 50°C. Under stirring conditions, add concentrated milk protein, concentrated whey protein, casein, collagen peptides, maltodextrin, polydextrose, sodium caseinate, taurine, compound vitamins, compound minerals, carrageenan, gellan gum, sucralose, steviol glycosides, sodium carbonate and edible flavoring in sequence, stir and dissolve evenly to obtain the initial mixture.

[0039] (2) Mix low erucic acid rapeseed oil, coconut oil, flaxseed oil, medium chain triglycerides, fish oil extract and phospholipids, and then add them to the above initial mixture. Stir at 700 r / min for 25 min to obtain a mixture of all materials.

[0040] (3) Inoculate the above-mentioned mixture of all materials with a compound fermentation agent (Lactobacillus plantarum: Streptococcus thermophilus: Saccharomyces boulardii = 3:2:1) at 0.3% of its total mass, and ferment at 37°C for 12 hours. After fermentation, sterilize at 88°C for 8 minutes and cool to 50°C.

[0041] (4) Degas the above fermented mixture under a vacuum of -0.08MPa for 12 min, then homogenize it under a pressure of 25MPa, and then sterilize it at 137℃ for 5s before filling it.

[0042] Comparative Examples 5-8 The only difference between Comparative Examples 5-8 and Example 1 is the composition of the compound fermentation agent in step (3), as shown in Table 1.

[0043] Table 1. Composition and mass ratio of fermentation bacteria

[0044] Effect test Test Example 1: Stability Test Samples from Examples 1-3 were placed in a constant temperature and humidity chamber (37℃±2℃, relative humidity 75%±5%) for accelerated storage testing. Samples were taken at 1, 3, and 6 months, and quantitative analysis was performed according to the following standard method: Centrifugal sedimentation rate: Accurately weigh each sample (9-9.5g, accuracy 0.1mg) into a centrifuge tube (10mL), centrifuge at 3000 r / min for 30 min, record the height of the fat float, discard the supernatant, and weigh the precipitate. Centrifugal sedimentation rate (%) = (precipitate weight / total sample weight) × 100%. The lower the centrifugal sedimentation rate, the better the suspension stability of the system.

[0045] Average particle size: The volume average particle size (D[4,3]) of the sample was determined using a Malvern laser particle size analyzer (Zetasizer Nano ZS90). The smaller the particle size and the narrower the distribution, the more stable the system.

[0046] Fat buoyancy: After centrifugation, remove the centrifuge tube, place it vertically upright, and observe and measure the height (mm) of the upper fat layer. A fat buoyancy height ≤2 mm is considered "small / slight buoyancy," while the opposite is "large buoyancy." The height of the fat layer reflects the fat emulsification effect; the lower the height, the better the emulsification effect.

[0047] Viscosity: The apparent viscosity (mPa·s) of the samples was measured using a Borelfeld rotational viscometer (DV2T, rotor S63, rotation speed 20 rpm, 25℃). During continuous testing, the more stable the viscosity value, the better the product stability; the greater the viscosity value fluctuation, the worse the product stability.

[0048] The results are shown in Table 2.

[0049] Table 2 Stability Test Results

[0050] As shown in Table 1, after accelerated storage at 37°C for 6 months, the centrifugal sedimentation rate of Examples 1-3 was less than 0.35%, the particle size remained below 300 nm, the fat float height was 0 mm, and the viscosity remained within the suitable range of 25.3-28.5 mPa·s. This indicates that the present invention, through a specific stepwise preparation process, constructs a highly stable complex emulsion system with excellent performance in all stability indicators.

[0051] The samples from Comparative Examples 1-8 were subjected to accelerated storage tests using the same method, and samples were taken for testing in the 6th month. The test results are shown in Table 3.

[0052] Table 3 Stability Test Results

[0053] Comparing Example 1 with Comparative Examples 1-4, it can be seen that while microencapsulation (Comparative Example 1) or fermentation (Comparative Example 2) alone can partially improve stability, significant precipitation, increased particle size, and fat buoyancy occur after 6 months. Comparative Examples 3 and 4 exhibit the worst stability. Only by combining fermentation and microencapsulation can all indicators remain excellent after 6 months, demonstrating a significant synergistic effect between the extracellular polysaccharides produced by fermentation and the stable oil droplets constructed by microencapsulation, jointly constructing a highly stable complex emulsion system.

[0054] The results of Comparative Examples 5-8 showed that the long-term stability of single-strain or dual-strain fermentation (even with microencapsulation) was significantly worse than that of the three-strain combination in Example 1, exhibiting higher precipitation rates and larger particle sizes. This indicates that the extracellular polysaccharides and other metabolites produced synergistically by *Lactobacillus plantarum*, *Streptococcus thermophilus*, and *Saccharomyces boulardii* are important for stability.

[0055] Test Example 2: Taste Test Thirty sensory evaluators (aged 25-55, half male and half female) were selected to conduct blind tests on the high-protein, high-energy nutrient solutions prepared in Examples 1-3 and Comparative Examples 1-8. Evaluation indicators included: Smoothness of texture (1-10 points, the higher the score, the smoother the texture and the less powdery or grainy it is); Odor intensity (1-10 points, the higher the score, the stronger the unpleasant odors such as fishy, ​​metallic, and protein smells); Flavor acceptability (1-10 points, the higher the score, the easier the overall flavor is to accept); Overall preference (1-10 points, the higher the score, the higher the overall preference for the product).

[0056] Rinse your mouth with water before evaluating each sample, and wait 3 minutes between samples.

[0057] The test results are shown in Table 4.

[0058] Table 4. Taste Test Results

[0059] As shown in Table 3, the smoothness of the taste of Examples 1-3 is above 8.8, the odor intensity is below 2.1, and the flavor acceptance and overall preference are both around 9.0, showing excellent sensory quality.

[0060] The significantly increased odor intensity in Comparative Examples 1-4 indicates that fermentation and microencapsulation treatments play a crucial role in masking the unpleasant odors of fish oil, minerals, and proteins. The odor masking effects of Comparative Examples 5-8 were all inferior to the three-bacterial compound fermentation in Example 1, suggesting a synergistic effect among *Lactobacillus plantarum*, *Streptococcus thermophilus*, and *Saccharomyces boulardii*, resulting in a richer and milder fermentation flavor profile.

[0061] Test Example 3: Oxidative Stability Test of Fish Oil The samples from Example 1 and Comparative Examples 1-4 were stored under accelerated conditions (37℃±2℃, relative humidity 75%±5%) for 6 months. Samples were taken at the 6th month to determine their peroxide value (POV, referring to GB 5009.227-2016) and anisidine value (p-AV, referring to GB / T 24304-2024) to assess the degree of oxidation of the fish oil. The results are shown in Table 5.

[0062] Table 5 Results of fish oil oxidative stability test

[0063] The peroxide value and anisidine value of Example 1 were 2.8 meq / kg and 6.5, respectively, indicating that the product of this invention has excellent oxidative stability during long-term storage. The peroxide value and anisidine value of Comparative Examples 1-4 all increased to varying degrees, indicating that fish oil oxidation is accelerated without microencapsulation protection. Fermentation treatment can further reduce oxidation indicators, demonstrating the synergistic effect between fermentation and microencapsulation.

[0064] Test Example 4: In Vitro Digestion and Absorption Rate Test Using the INFOGEST 2.0 in vitro digestion model, simulated gastrointestinal digestion experiments were conducted on the samples prepared in Example 1 and Comparative Examples 1-4. The protein digestibility (measured by the o-phthalaldehyde method to determine the increase rate of free amino groups) after the gastric digestion stage (2 hours) and the fat digestibility (measured by the pH-stat method to determine the release rate of free fatty acids) after the intestinal digestion stage (2 hours) were measured. The results are shown in Table 6.

[0065] Table 6 Results of in vitro digestibility test

[0066] Example 1 showed significantly higher protein and fat digestibility than the comparative examples. Comparative Example 2 had higher protein digestibility due to pre-degradation of the protein during fermentation; however, its fat digestibility was lower because of insufficient fat emulsification due to the lack of microencapsulation. Comparative Example 1 had better fat digestibility than Comparative Example 2, but lower protein digestibility. Only Example 1 combined both, achieving high protein and high fat digestibility simultaneously.

[0067] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a high-protein high-energy nutritional liquid, characterized by, Includes the following steps: (1) Mix a portion of concentrated milk protein, a portion of concentrated whey protein and a portion of casein with maltodextrin, polydextrose, sodium caseinate and water, sterilize and cool to obtain a protein-carbohydrate matrix solution. (2) Inoculate the protein-carbohydrate matrix liquid with a compound fermentation agent, ferment, sterilize, and cool to obtain a fermentation base liquid; the compound fermentation agent is composed of Lactobacillus plantarum, Streptococcus thermophilus and Saccharomyces boulardii in a mass ratio of 2-5:1-3:0.5-2. (3) Mix low-erucic acid rapeseed oil, coconut oil, flaxseed oil and a portion of medium-chain triglycerides to obtain a mixed vegetable oil; mix fish oil extract with phospholipids and then add it to the mixed vegetable oil to obtain a composite oil phase; dissolve fat-soluble complex vitamins in the remaining medium-chain triglycerides and add them to the composite oil phase to obtain a fat-soluble premix; (4) Mix the remaining concentrated milk protein, concentrated whey protein and casein with collagen peptides, taurine, water-soluble complex vitamins, complex minerals and water to obtain a water-soluble functional premix. (5) Mix carrageenan and gellan gum with water to obtain a colloidal solution; (6) Add the colloidal solution to the fermentation base liquid, then add the fat-soluble premix and the water-soluble functional premix in sequence, mix, then add sweetener, pH adjuster, edible flavor and water, deaerate, homogenize, sterilize, and fill to obtain the product.

2. The production method according to claim 1, characterized by, The high-protein, high-energy nutrient solution comprises, by weight, 30-60 parts concentrated milk protein, 10-30 parts concentrated whey protein, 5-15 parts casein, 15-30 parts rapeseed oil, 5-15 parts coconut oil, 5-20 parts collagen peptides, 0.05-0.3 parts fish oil extract, 2-8 parts flaxseed oil, 5-20 parts medium-chain triglycerides, 50-100 parts maltodextrin, and 10-30 parts polydextrose. 1 part, sodium caseinate 2-8 parts, phospholipids 1-5 parts, fat-soluble vitamins 0.3-1.2 parts, water-soluble complex vitamins 0.2-0.8 parts, complex minerals 1-5 parts, taurine 0.1-0.8 parts, carrageenan 0.2-1.0 parts, gellan gum 0.1-0.5 parts, sweetener 0.01-0.2 parts, pH adjuster 0.1-0.5 parts, edible flavoring 0.5-2 parts, and water 700-850 parts.

3. The preparation method according to claim 2, characterized in that, In step (1), the partial concentrated milk protein, partial concentrated whey protein, and partial casein constitute 50%-70%, 50%-70%, and 50%-70% of the total formula amount, respectively, and the amount of water used is 40%-50% of the total water amount of the formula; the sterilization temperature is 90-95℃, the sterilization time is 10-15 min, and the temperature is cooled to 35-38℃; the mixing conditions are: stirring at 600-800 r / min for 20-30 min, and the water temperature is 45-55℃.

4. The preparation method according to claim 2, characterized in that, The inoculation amount of the compound fermentation agent in step (2) is 0.1%-0.5% of the mass of the protein-carbohydrate matrix liquid. The fermentation temperature is 35-38℃, the fermentation time is 6-16h, the sterilization temperature is 85-90℃, the sterilization time is 5-10 min, and the temperature is cooled to 45-50℃.

5. The preparation method according to claim 2, characterized in that, The temperature of the mixed vegetable oil in step (3) is 40-50℃; the medium-chain triglycerides account for 70%-90% of the total amount of the formula, and the remaining medium-chain triglycerides account for 10%-30% of the total amount of the formula.

6. The preparation method according to claim 2, characterized in that, In step (4), the remaining concentrated milk protein, concentrated whey protein and casein are 30%-50%, 30%-50% and 30%-50% of the total amount of the formula, respectively. The amount of water used is 15%-20% of the total amount of water in the formula, and the temperature is 45-55℃. In step (5), the amount of water used is 5%-8% of the total amount of water in the formula, and the temperature is 75-85℃. After mixing, the temperature is lowered to 45-55℃.

7. The preparation method according to claim 2, characterized in that, In step (6), the degassing vacuum degree is -0.06 to -0.09 MPa and the time is 10-15 min; the homogenization pressure is 20-30 MPa; and the sterilization temperature is 135-140℃ and the time is 3-8 s.

8. The preparation method according to claim 1, characterized in that, The fat-soluble complex vitamin is selected from one or more of vitamin A, vitamin D, and vitamin E; the water-soluble complex vitamin is selected from one or more of vitamin B1, vitamin B2, vitamin B6, vitamin B12, niacin, folic acid, and pantothenic acid; the complex mineral is selected from one or more of magnesium oxide, ferric pyrophosphate, zinc sulfate, and sodium selenite; the sweetener is sucralose and / or steviol glycosides; and the pH adjuster is sodium carbonate and / or sodium citrate.

9. A high-protein, high-energy nutrient solution prepared by the preparation method according to any one of claims 1-8.

10. The use of a high-protein, high-energy nutrient solution prepared by the preparation method according to any one of claims 1-8 in the preparation of products that provide nutritional support.

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