A process for the preparation of a fat-flavored starch milk carbohydrate-based gel

Abstract

The application discloses a preparation method of a fat-flavor starch milk carbohydrate-based gel and relates to the technical field of starch lipid-structured gel processing. The method comprises the following steps: S1, taking rice protein in rice milk powder as raw material, adding deionized water according to a material-liquid ratio of 1:5-10, adjusting pH to 6.5-8.0, adding a compound protease, the enzyme addition amount being 0.5%-2.0% of the mass of the protein, carrying out enzymolysis at 50-55 DEG C for 4-8 hours, raising the temperature to 90 DEG C to inactivate the enzyme for 15 minutes after the enzymolysis is completed, and centrifuging to obtain an enzymolysis peptide mixture by taking the supernatant; the method is characterized in that the specific proportion of alkaline protease and flavor protease is adopted to compoundly hydrolyze the rice protein, the enzymolysis liquid rich in hydrophobic amino acid residue exposed peptide segments is obtained, the rice starch is hydrolyzed by steps to obtain a sugar syrup with moderate viscosity and a reducing end group, the precise matching of the peptide segments and sugar molecules is realized, and a short-time flash evaporation process is adopted.

Description

Technical Field

[0001] This invention relates to the field of starch lipid esterification gel processing technology, specifically to a method for preparing a fatty-flavored starch milk carbohydrate-based gel. Background Technology

[0002] Fat flavor is a core component of food sensory quality, encompassing not only the olfactory characteristics of the fat itself, such as volatile buttery and nutty aromas, but also the smoothness, richness, and oiliness of the mouth, as well as the persistence of flavor release. With increasing consumer health awareness, the market demand for low-fat and reduced-fat foods is experiencing rapid and sustained growth. However, removing or reducing fat directly leads to bland flavor, coarse texture, and insufficient aftertaste, severely impacting the sensory quality and market competitiveness of products. Therefore, developing alternative technologies that can efficiently simulate fat flavor and texture has become a critical technical problem urgently needing to be solved in the current food processing industry. Fat-flavored starch, as an important branch of carbohydrate-based fat substitutes, has become a research hotspot in this field due to its significant advantages, including wide availability of raw materials, low production costs, high food safety, and good compatibility with food systems.

[0003] The Maillard reaction is a complex cascade reaction between amino and carbonyl compounds in food, and is a major pathway for the formation of food aroma and color. Current research indicates that oligopeptides, compared to free amino acids, participate more effectively in the formation of flavor compounds such as pyrazines in the Maillard reaction system, and can produce unique peptide-specific volatile substances. Food-derived peptide mixtures, due to their diverse nitrogen source composition, are widely used as aroma precursors or functional components. The enzymatic hydrolysis of natural proteins to generate peptide-rich substrates, followed by Maillard reactions to prepare aroma-enhancing compounds with ideal sensory properties, has become a common technical strategy for food flavor regulation. Peptides with different amino acid compositions, sequences, and chain lengths can produce diverse and unique aromatic characteristics, enabling the controlled formation and stable release of aromas from peptide-derived Maillard reaction products during heat treatment.

[0004] In existing technologies, protein hydrolysates are mostly used to provide umami or meaty flavor characteristics, while starch syrups are mainly used as sweeteners or texture fillers. Although a simple combination of the two can produce some lipid aromas after conventional thermal reaction treatment, it is difficult to form a molecular structure that can simulate the oral tactile sensation of fat, and thus cannot achieve a true enhancement of the fat sensation. Although traditional carbohydrate-based or protein-based microparticle fat substitutes can simulate some texture characteristics, they have obvious shortcomings in terms of flavor richness and aftertaste fullness. Moreover, conventional heating concentration or vacuum concentration processes tend to retain undesirable flavors such as bitterness and rancidity produced by enzymatic hydrolysis, or excessively destroy flavor precursors, resulting in unnatural product flavors and poor thermal stability, making it difficult to meet the needs of high-temperature processing scenarios such as baking and UHT sterilization. Therefore, developing a method for preparing a fat-flavored starch milk carbohydrate-based gel is of great significance. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a fatty-flavored starch milk carbohydrate-based gel. This method can prepare peptides with fatty-feel binding ability and suitable starch hydrolysate through a specific enzymatic hydrolysis process. Combined with a flash evaporation process, it can achieve precise control of flavor substances and directional formation of peptide-glycan complexes. Finally, a carbohydrate-based gel that can significantly improve the fatty feel of food, has a natural flavor, good thermal stability, and meets the requirements of clean labeling is obtained.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a fat-flavored starch milk carbohydrate-based gel, the method comprising the following steps:

[0007] S1. Using rice protein from rice milk powder as raw material, add deionized water at a material-to-liquid ratio of 1:5-10, adjust the pH to 6.5-8.0, add a complex protease, with the enzyme addition amount being 0.5%-2.0% of the protein mass, and enzymatically hydrolyze at 50-55℃ for 4-8 hours. After enzymatic hydrolysis, raise the temperature to 90℃ to inactivate the enzyme for 15 minutes, centrifuge and take the supernatant to obtain the enzymatically hydrolyzed peptide mixture. This complex enzymatic hydrolysis system can accurately cut the peptide bonds of rice protein, avoid excessive enzymatic hydrolysis to produce small free amino acids, and maximize the exposure of hydrophobic amino acid residues such as leucine, phenylalanine, and valine in the peptide chain. These hydrophobic peptide segments can simulate the hydrophobic interaction between fat molecules and salivary proteins in the oral cavity, laying the core molecular basis for the subsequent formation of a fatty sensation.

[0008] S2. Using rice starch from rice milk powder as raw material, adjust the slurry to 15-25°Bé, adjust the pH to 5.5-6.5, add heat-resistant α-amylase at a concentration of 0.1%-0.3% of the dry starch, liquefy at 90-95°C for 30-60 minutes, cool to 55-60°C, add a mixture of glucoamylase and pullulanase at a concentration of 0.2%-0.5% of the dry starch, and saccharify for 12-24 hours to obtain starch hydrolysate. This stepwise enzymatic hydrolysis process can precisely control the degree of starch hydrolysis, avoid generating a large amount of monosaccharides that would cause the product to be too sweet and mask the fat flavor, and at the same time make the syrup have a molecular weight distribution and reducing terminal group that match the enzymatically hydrolyzed peptides, providing sufficient and suitable reaction sites for the formation of peptide-glycan complexes, and ensuring the stability of the subsequent compounding system.

[0009] S3. Mix the enzymatically hydrolyzed peptide mixture with the starch hydrolyzed syrup at a solid mass ratio of 1:1.5-3, adjust the pH to 6.0-7.5, pump the mixture into the flash evaporation equipment, control the feed temperature to 85-95℃, the absolute pressure of the flash evaporation chamber to 10-50kPa, and the flash evaporation time to 3-10 seconds, and collect the flash evaporation concentrate. This short-time flash evaporation process is different from the traditional long-time vacuum concentration. Its instantaneous decompression vaporization process can efficiently remove short-chain fatty acids, primary amines and other low-boiling-point bitter and rancid undesirable flavor substances generated during enzymatic hydrolysis without destroying the heat-sensitive medium and long-chain flavor precursors. At the same time, the energy released by the rapid phase change of the system promotes the formation of stable covalent bonds and hydrophobic interactions between peptides and sugar molecules, and directionally generates peptide-sugar complexes that can form a lubricating film structure at oral temperature.

[0010] S4. Mix rice milk powder with deionized water and perform high-speed shearing and stirring to form a rice milk system. Add 10-100 ppm flash evaporation concentrate to the rice milk system, stir evenly, and then sterilize. Cool and keep warm to form a fat-flavored starch milk carbohydrate-based gel. The high-speed shearing process allows the starch particles in the rice milk powder to fully absorb water, gelatinize, and break down to form a uniform continuous phase. The subsequent slow cooling and keeping process allows the peptide-sugar complex to be evenly embedded in the three-dimensional network structure of the starch gel, forming a gel system with a structure similar to the thermal phase change of natural fats. This ensures that the gel can slowly melt in the mouth with body temperature and continuously release a creamy flavor, producing a lasting smooth and rich feeling.

[0011] Furthermore, the rice milk powder used in S1 is first passed through an 80-100 mesh standard sieve to remove impurities. After adding deionized water according to the material-to-liquid ratio, the mixture is stirred at 300-500 r / min for 10-15 minutes until the system is homogeneous. The complex protease is composed of alkaline protease and flavor protease mixed at a mass ratio of 2:1. During the enzymatic hydrolysis process, the pH of the system is checked every 2 hours and maintained at 6.5-8.0. After enzyme inactivation, the system is centrifuged at 3000-5000 r / min for 10-15 minutes. The molecular weight of the peptides in the resulting enzymatically hydrolyzed peptide mixture is mainly distributed between 500-3000 Da. The enzymatically hydrolyzed peptide mixture contains peptides with exposed leucine, phenylalanine, and valine residues. Checking and maintaining the pH of the system every 2 hours ensures that the alkaline protease and flavor protease are always in the optimal catalytic activity range, avoiding uneven molecular weight distribution of the enzymatic hydrolysis products due to enzyme activity fluctuations, and ensuring the generation and activity of hydrophobic peptides.

[0012] Furthermore, when adding deionized water to the slurry in step S2, a stirrer is used to stir at a speed of 400-600 r / min for 15-20 minutes until the starch granules are completely dispersed. Then, heat-resistant α-amylase is added for liquefaction treatment. The liquefaction endpoint is determined using the iodine solution test method; at the liquefaction endpoint, the iodine solution turns brownish-red. The DE value of the liquefied liquid is controlled to be 8-12. The mixed enzymes of glucoamylase and pullulanase are mixed at a mass ratio of 3:1. The DE value is measured every 4 hours during saccharification. After saccharification, the DE value of the resulting starch hydrolysate is 25-35. The starch hydrolysate is composed of maltodextrin and oligosaccharides. The iodine solution test method is used to determine the liquefaction endpoint, which allows for direct and accurate control of the degree of starch liquefaction, avoiding incomplete liquefaction leading to insufficient subsequent saccharification or excessive liquefaction resulting in excessively low syrup viscosity, ensuring that the final syrup viscosity and reducing sugar content meet the requirements.

[0013] Furthermore, before mixing the enzymatically hydrolyzed peptide mixture and the starch hydrolyzed syrup in S3, the solid content of each is measured separately, and the feeding amount is calculated according to the solid mass ratio. During mixing, a stirrer is used to stir at a speed of 500-700 r / min for 20-30 minutes until the system is completely homogeneous. After the material enters the flash chamber, it vaporizes instantly, and the material temperature drops rapidly to 50-60℃. The vapor generated by vaporization is condensed and recovered by a condenser. During the flash evaporation process, the material is continuously fed and the flash concentrate is continuously collected. The solid content of the flash concentrate is controlled at 40%-50%. Pre-measuring the solid content and feeding according to the ratio can ensure that the reaction molar ratio of peptides and sugar molecules is accurately controllable, avoiding insufficient peptide-sugar complex formation due to imbalance of ratio. At the same time, controlling the solid content of the flash concentrate at 40%-50% can ensure the optimal concentration conditions required for subsequent gel formation.

[0014] Furthermore, the rice milk powder used in S4 is first passed through an 80-100 mesh standard sieve. The rice milk powder and deionized water are mixed at a mass ratio of 1:8-12. The mixture is then sheared and stirred at a high-speed shear machine at a speed of 8000-12000 r / min for 5-10 minutes. During the shearing process, the system temperature is controlled at 20-30℃ to form a uniform and stable rice milk system. After adding the flash evaporation concentrate to the rice milk system, the mixture is stirred at a speed of 200-400 r / min for 10-15 minutes until the flash evaporation concentrate is completely dispersed. Subsequently, a vacuum degassing treatment is performed for 5-10 minutes. During the shearing process, the system temperature is controlled at 20-30℃ to avoid premature gelatinization of starch particles, which would lead to uneven shearing. The vacuum degassing treatment can remove tiny air bubbles in the system and prevent the formation of pores inside the gel, which would affect the uniformity of its texture and taste.

[0015] Furthermore, after the flash concentrate in step S4 is completely dispersed and degassed, the system is dispensed into sterile food-grade polypropylene containers and subjected to high-temperature and high-pressure rotary sterilization at 121°C for 15 minutes. After sterilization, the system is naturally cooled to 25°C, avoiding violent vibration during the cooling process. The system is kept at 25°C for 2 hours, and a gel-like fatty-flavored starch milk carbohydrate-based gel is naturally formed. The rotary high-temperature and high-pressure sterilization process ensures uniform heating of all parts of the system and avoids local overheating that could damage flavor substances. Avoiding violent vibration during the cooling process can prevent the starch gel network structure from breaking, ensuring that the gel forms a uniform and dense gel-like structure.

[0016] Furthermore, in step S1, the pH of the system is adjusted to 6.5-8.0 using a 0.1 mol / L sodium hydroxide solution. During enzymatic hydrolysis, a constant temperature water bath is used to maintain the system temperature. During enzyme inactivation, the system is continuously stirred at a speed of 100-200 r / min. After enzyme inactivation, plate and frame filtration is used to remove large molecular protein precipitates, followed by centrifugation. The precipitate after centrifugation is washed once with an equal volume of deionized water, and the supernatants are combined. Using plate and frame filtration to remove large molecular protein precipitates before centrifugation can improve centrifugation efficiency and reduce the impurity content in the supernatant. Washing the precipitate and combining the supernatants can improve the recovery rate of enzymatically hydrolyzed peptides and reduce raw material loss.

[0017] Furthermore, in step S2, the pH of the system is adjusted to 5.5-6.5 using a 0.1 mol / L hydrochloric acid solution. During liquefaction, a constant temperature water bath is used to maintain the system temperature at 90-95℃, while the system is continuously stirred at a speed of 200-300 r / min. After liquefaction, the temperature is first raised to 100℃ and held for 5 minutes to inactivate the thermoresistant α-amylase, and then lowered to 55-60℃ for saccharification. During saccharification, the same stirring speed is maintained. After saccharification, the temperature is raised to 90℃ and held for 10 minutes to inactivate the saccharifying enzyme. Inactivating the thermoresistant α-amylase before saccharification after liquefaction avoids the thermoresistant α-amylase from continuing to hydrolyze starch, which could lead to uncontrolled saccharification. Inactivating the enzyme again after saccharification terminates the enzymatic reaction and ensures the stability of the syrup quality.

[0018] Furthermore, in step S3, a 0.1 mol / L sodium hydroxide solution or a 0.1 mol / L hydrochloric acid solution is used to adjust the pH of the mixture to 6.0-7.5. The mixture is pumped into the flash evaporation equipment via a diaphragm metering pump. The feed flow rate is precisely adjusted by a frequency converter to a range of 50-150 L / h. The interior of the flash evaporation chamber is made of smooth 304 stainless steel, and the inner wall temperature is maintained within a range not exceeding 5°C from the feed temperature. The vacuum degree of the flash evaporation chamber is kept stable by a vacuum pump and a regulating valve linkage control. The use of a diaphragm metering pump in conjunction with a frequency converter to adjust the feed flow rate enables precise and stable control of the feed amount. The use of smooth 304 stainless steel for the inner wall of the flash evaporation chamber and the control of the inner wall temperature prevent the material from sticking to the wall and charring, resulting in unpleasant flavors. The vacuum degree linkage control ensures the stability and consistency of the flash evaporation process.

[0019] Furthermore, the fat-flavored starch milk carbohydrate-based gel prepared by this method has a pale yellow to milky white gel-like appearance, and the gel exhibits a shear rate of 10-100 s⁻¹. -1 It exhibits shear-thinning behavior within a certain range and can withstand high-temperature treatment at 120°C for 20 minutes. The gel is added to low-fat milk and dairy products, sauces, soups, and baking fillings at a ratio of 3%-10% by mass. During the addition process, a low-speed stirring method is used to ensure that the gel is completely mixed with the food system.

[0020] Compared with existing technologies, this method for preparing fat-flavored starch milk carbohydrate-based gel has the following advantages:

[0021] This invention utilizes a specific ratio of alkaline protease and flavor protease to enzymatically hydrolyze rice protein, obtaining an enzymatic hydrolysate rich in exposed peptides with hydrophobic amino acid residues. Further enzymatic hydrolysis of rice starch yields a syrup with appropriate viscosity and reducing end groups, achieving precise matching between peptides and sugar molecules. A short-time flash evaporation process, applied at 10-50 kPa absolute pressure for 3-10 seconds, rapidly removes undesirable low-boiling-point flavor substances such as bitterness and rancidity produced during enzymatic hydrolysis. Simultaneously, it promotes the formation of a complex with a fat-lubricating membrane structure between peptides and sugars. The resulting gel significantly enhances the fatty, smooth texture and creamy flavor of the food, while exhibiting excellent thermal stability, withstanding high-temperature treatment at 120°C for 20 minutes, retaining over 85% of its fatty flavor. Furthermore, it requires no artificial emulsifiers and meets clean label requirements.

[0022] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0024] Figure 1 A flowchart illustrating a method for preparing a fatty-flavored starch milk carbohydrate-based gel;

[0025] Figure 2 A flowchart illustrating the steps involved in preparing a fat-flavored starch milk carbohydrate-based gel.

[0026] Figure 3 This is a schematic diagram of HPLC analysis and structural characterization of the glycopeptide complex. Detailed Implementation

[0027] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0028] This invention addresses the problems of bland flavor and coarse texture in existing low-fat foods due to reduced fat content, as well as the shortcomings of traditional fat substitutes such as insufficient flavor complexity and poor thermal stability. It proposes a method for preparing a fat-flavored starch milk carbohydrate-based gel, the complete technical solution of which is as follows.

[0029] First, rice protein complex enzymatic hydrolysis is performed. Rice milk powder is passed through an 80-100 mesh standard sieve. Rice protein is taken and added to deionized water at a material-to-liquid ratio of 1:5-10. The mixture is stirred at 300-500 rpm for 10-15 minutes until the system is homogeneous. The pH is adjusted to 6.5-8.0. A complex protease, consisting of alkaline protease and flavor protease mixed at a mass ratio of 2:1, is added. The amount of enzyme added is 0.5%-2.0% of the protein mass. Enzymatic hydrolysis is carried out at 50-55℃ for 4-8 hours. During the enzymatic hydrolysis process, the pH is monitored every 2 hours and maintained to ensure stability. The temperature is raised to 90℃ to inactivate the enzyme for 15 minutes. Large molecular weight protein precipitates are removed by plate and frame filtration. Then, the mixture is centrifuged at 3000-5000 rpm for 10-15 minutes. The precipitate is washed with an equal volume of deionized water, and the supernatants are combined to obtain a mixed solution of enzymatically hydrolyzed peptides with molecular weights mainly distributed in the range of 500-3000 Da.

[0030] Next, the rice starch was subjected to stepwise enzymatic hydrolysis. Rice starch from rice milk powder was slurried to 15-25°Bé and stirred at 400-600 r / min for 15-20 minutes until the starch granules were completely dispersed. The pH was adjusted to 5.5-6.5, and 0.1%-0.3% of heat-resistant α-amylase (based on dry starch) was added. The mixture was liquefied at 90-95°C for 30-60 minutes until the iodine solution turned brownish-red and the DE value was 8-12. The temperature was raised to 100°C and kept at that temperature for 5 minutes to inactivate the enzyme. The temperature was lowered to 55-60°C, and 0.2%-0.5% of a mixture of glucoamylase and pullulanase (based on dry starch) with a mass ratio of 3:1 was added. The mixture was saccharified for 12-24 hours until the DE value was 25-35. The temperature was raised to 90°C and kept at that temperature for 10 minutes to inactivate the enzyme and obtain the starch hydrolysate syrup.

[0031] Next, flash evaporation is performed. The enzymatically hydrolyzed peptide mixture and starch hydrolyzed syrup are mixed at a solids mass ratio of 1:1.5-3. The pH is adjusted to 6.0-7.5. The mixture is pumped into the flash evaporation equipment at a feed flow rate of 50-150 L / h. The feed temperature is controlled at 85-95℃, the absolute pressure in the flash chamber is 10-50 kPa, and the treatment time is 3-10 seconds. The flash concentrate with a solids content of 40%-50% is collected.

[0032] Finally, to prepare the finished gel, rice milk powder that has passed through an 80-100 mesh sieve is mixed with deionized water at a mass ratio of 1:8-12. The mixture is then sheared at a high speed of 8000-12000 rpm for 5-10 minutes, maintaining the system temperature at 20-30℃ to form a rice milk system. 10-100 ppm of flash-evaporated concentrate is added, and the mixture is stirred at 200-400 rpm for 10-15 minutes, followed by vacuum degassing for 5-10 minutes. The mixture is then sterilized at 121℃ under high pressure for 15 minutes, naturally cooled to 25℃, and held at that temperature for 2 hours, ultimately forming a gel-like, fat-flavored starch milk carbohydrate-based gel. This gel exhibits shear-thinning properties, can withstand high-temperature treatment at 120℃ for 20 minutes, and can be added to various low-fat foods at a ratio of 3%-10%, requiring no artificial emulsifiers and meeting clean label requirements.

[0033] Example 1

[0034] This embodiment uses the optimal intermediate process parameters described in the patent to prepare a fat-flavored starch milk carbohydrate-based gel. By precisely controlling the degree of complex enzymatic hydrolysis and the stepwise enzymatic hydrolysis conditions, combined with a short-time flash evaporation process, a peptide-glycoside complex is formed in a directional manner. The aim is to obtain a gel product with the best overall performance, which is suitable for fat substitution applications in most low-fat foods.

[0035] See Figure 1 and Figure 2 The specific implementation process of this embodiment is as follows:

[0036] S1. Enzymatic hydrolysis of rice protein complex: Rice milk powder was passed through an 80-mesh standard sieve. Rice protein was added to deionized water at a material-to-liquid ratio of 1:7. The mixture was stirred at 400 rpm for 12 minutes until homogeneous. The pH was adjusted to 7.2 using 0.1 mol / L sodium hydroxide solution. A complex protease, consisting of alkaline protease and flavor protease mixed at a mass ratio of 2:1, was added at a concentration of 1.2% of the protein mass. Enzymatic hydrolysis was carried out in a constant temperature water bath at 52℃ for 6 hours. The pH of the system was checked every 2 hours during the hydrolysis process and maintained at 7.2, while stirring continuously at 150 rpm. After hydrolysis, the temperature was raised to 90℃ for 15 minutes to inactivate the enzyme, while maintaining stirring during the inactivation process. The mixture was first filtered through a plate and frame filter to remove large molecular weight protein precipitates, and then centrifuged at 4000 rpm for 12 minutes. The precipitate was washed once with an equal volume of deionized water, and the supernatants were combined to obtain a mixed solution of enzymatically hydrolyzed peptides with molecular weights mainly distributed in the range of 500-3000 Da.

[0037] S2. Stepwise enzymatic hydrolysis of rice starch: Rice starch from rice milk powder was slurried to 20°Bé and stirred at 500 rpm for 18 minutes until the starch granules were completely dispersed. The pH was adjusted to 6.0 using 0.1 mol / L hydrochloric acid solution. 0.2% of thermoresistant α-amylase (based on dry starch) was added, and the mixture was liquefied in a 92°C constant temperature water bath for 45 minutes. The liquefaction endpoint was determined using the iodine test method; at this point, the iodine solution was brownish-red, and the DE value of the liquefied solution was 10. The temperature was raised to 100°C and held for 5 minutes to inactivate the thermoresistant α-amylase. The temperature was then lowered to 58°C, and 0.35% of a mixed enzyme of glucoamylase and pullulanase (based on dry starch) at a mass ratio of 3:1 was added. Saccharification was carried out for 18 hours, with the DE value measured every 4 hours during the saccharification process. The final DE value was 30. The temperature was raised to 90°C and held for 10 minutes to inactivate the saccharifying enzyme, yielding an enzymatically hydrolyzed syrup composed of maltodextrin and oligosaccharides.

[0038] S3. Flash evaporation is used to prepare a concentrated solution. The solid content of the enzymatically hydrolyzed peptide mixture and the starch hydrolyzed syrup are determined separately. They are mixed at a solid mass ratio of 1:2. The pH of the mixture is adjusted to 6.8 using 0.1 mol / L sodium hydroxide solution. The mixture is pumped into the flash evaporator at a feed rate of 100 L / h using a diaphragm metering pump. The feed temperature is controlled at 90℃, the absolute pressure in the flash chamber is 30 kPa, and the flash evaporation time is 6 seconds. The flash chamber is made of smooth 304 stainless steel, and the inner wall temperature is maintained at 88℃. The vacuum degree is maintained stable by a vacuum pump and a regulating valve. Upon entering the flash chamber, the material instantly vaporizes, and the temperature rapidly drops to 55℃. The vaporized steam is condensed and recovered, and the flash concentrate is continuously collected, with its solid content controlled at 45%. (See also...) Figure 3 HPLC analysis and structural characterization clearly revealed the characteristic peaks of the peptide-glycoside complex, confirming that the flash evaporation process effectively promoted the covalent bonding and hydrophobic interaction between peptides and sugar molecules.

[0039] S4. Construction and gel formation of the rice milk system: Rice milk powder passing through an 80-mesh standard sieve was mixed with deionized water at a mass ratio of 1:10. The mixture was then sheared and stirred at 10,000 rpm for 7 minutes using a high-speed shear mill, maintaining the system temperature at 25°C during the shearing process to form a homogeneous and stable rice milk system. 50 ppm of flash-evaporated concentrate was added to the rice milk system, and the mixture was stirred at 300 rpm for 12 minutes until the flash-evaporated concentrate was completely dispersed. Subsequently, vacuum degassing was performed for 7 minutes. The system was dispensed into sterile food-grade polypropylene containers and sterilized using a high-temperature, high-pressure rotary sterilizer at 121°C for 15 minutes. After sterilization, the mixture was allowed to cool naturally to 25°C, avoiding violent vibration during the cooling process. The mixture was then kept at 25°C for 2 hours, allowing the system to naturally form a gel-like, fat-flavored starch milk carbohydrate-based gel.

[0040] In summary, the gel prepared in this embodiment has a uniform, milky-white, gel-like appearance and exhibits good performance at shear rates of 10-100 s. -1It exhibits typical shear-thinning behavior within the specified range, can withstand high-temperature treatment at 120℃ for 20 minutes, and retains 92% of its fat content. The gel has a natural creamy aroma and a smooth mouthfeel, without any unpleasant flavors such as bitterness or rancidity. When added to low-fat yogurt at a ratio of 6%, the product has a rich and full-bodied taste, a long-lasting flavor release, and an overall sensory score significantly higher than similar commercially available fat substitutes, fully meeting clean label requirements.

[0041] Example 2

[0042] This embodiment uses process parameters with a low degree of enzymatic hydrolysis and short flash evaporation to prepare a fat-flavored starch milk carbohydrate-based gel. By controlling the enzymatic hydrolysis time and flash evaporation intensity, a gel product with a light flavor and delicate texture is obtained, which is suitable for food systems that require a refreshing flavor, such as low-fat milk beverages and light seasoning sauces.

[0043] See Figure 1 and Figure 2 The specific implementation process of this embodiment is as follows:

[0044] S1. Enzymatic hydrolysis of rice protein complex: Rice milk powder is passed through a 90-mesh standard sieve. Rice protein is added to deionized water at a material-to-liquid ratio of 1:5. The mixture is stirred at 300 rpm for 10 minutes until homogeneous. The pH is adjusted to 6.5 using 0.1 mol / L sodium hydroxide solution. A complex protease, consisting of alkaline protease and flavor protease mixed at a mass ratio of 2:1, is added at a concentration of 0.5% of the protein mass. Enzymatic hydrolysis is carried out in a 50°C constant temperature water bath for 4 hours. The pH of the system is checked every 2 hours during the hydrolysis process and maintained at 6.5, while continuous stirring at 100 rpm. After hydrolysis, the temperature is raised to 90°C for 15 minutes to inactivate the enzyme. The mixture is first filtered through a plate and frame filter to remove large protein precipitates, then centrifuged at 3000 rpm for 10 minutes. The precipitate is washed with an equal volume of deionized water, and the supernatants are combined to obtain a hydrolyzed peptide mixture.

[0045] S2. Stepwise enzymatic hydrolysis of rice starch: Rice starch from rice milk powder was slurried to 15°Bé and stirred at 400 rpm for 15 minutes until the starch granules were completely dispersed. The pH was adjusted to 5.5 using 0.1 mol / L hydrochloric acid solution. 0.1% (by dry starch) of thermostable α-amylase was added, and the mixture was liquefied in a 90°C water bath for 30 minutes. The solution turned brownish-red when tested with iodine solution, and the DE value of the liquefied solution was 8. The temperature was raised to 100°C and held for 5 minutes to inactivate the enzyme. The temperature was lowered to 55°C, and 0.2% (by dry starch) of a mixture of glucoamylase and pullulanase (mass ratio 3:1) was added. Saccharification was carried out for 12 hours, resulting in a final DE value of 25. The temperature was raised to 90°C and held for 10 minutes to inactivate the enzyme, yielding the starch hydrolysate syrup.

[0046] S3. Flash evaporation to prepare concentrate: Mix enzymatically hydrolyzed peptide mixture and starch hydrolyzed syrup at a solids mass ratio of 1:1.5, adjust pH to 6.0, pump into flash evaporation equipment at a feed flow rate of 50 L / h, control feed temperature at 85℃, absolute pressure in flash chamber at 10 kPa, flash evaporation time at 3 seconds, and collect flash concentrate with a solids content of 40%.

[0047] S4. Construction and gel formation of the rice milk system: Rice milk powder passing through a 90-mesh standard sieve was mixed with deionized water at a mass ratio of 1:8. The mixture was sheared and stirred at 8000 rpm for 5 minutes, with the system temperature controlled at 20°C to form the rice milk system. 10 ppm of flash-distilled concentrate was added, and the mixture was stirred at 200 rpm for 10 minutes, followed by vacuum degassing for 5 minutes. The mixture was then sterilized at 121°C under high pressure for 15 minutes, naturally cooled to 25°C, and kept at that temperature for 2 hours to obtain a fat-flavored starch milk carbohydrate-based gel.

[0048] In summary, the gel prepared in this embodiment has a light milky white, gel-like appearance, a delicate and smooth texture, a mild and mellow flavor, and no obvious heaviness. The product exhibits good thermal stability; after treatment at 120℃ for 20 minutes, the fat content is retained at 86%. Adding 3% to low-fat milk beverages significantly enhances the smoothness of the drink without masking the original flavor of the raw materials. The product demonstrates excellent stability, showing no stratification or sedimentation after 30 days of storage, making it suitable for low-fat food systems that prioritize a refreshing taste.

[0049] Example 3

[0050] This embodiment uses process parameters with a high degree of enzymatic hydrolysis and a long flash evaporation time to prepare a fat-flavored starch milk carbohydrate-based gel. By increasing the amount of enzyme added and extending the flash evaporation time, the formation of peptide-glycoside complexes and the enrichment of flavor substances are enhanced, resulting in a gel product with a rich flavor and thick texture, which is suitable for food systems that require a strong fat feel, such as baking fillings, thick soups, and high-fat sauces.

[0051] See Figure 1 and Figure 2 The specific implementation process of this embodiment is as follows:

[0052] S1. Enzymatic hydrolysis of rice protein complex: Rice milk powder is passed through a 100-mesh standard sieve. Rice protein is added to deionized water at a material-to-liquid ratio of 1:10. The mixture is stirred at 500 rpm for 15 minutes until homogeneous. The pH is adjusted to 8.0 using 0.1 mol / L sodium hydroxide solution. A complex protease, consisting of alkaline protease and flavor protease mixed at a mass ratio of 2:1, is added at a concentration of 2.0% of the protein mass. Enzymatic hydrolysis is carried out in a constant temperature water bath at 55℃ for 8 hours. The pH of the system is checked every 2 hours during the hydrolysis process and maintained at 8.0, while stirring continuously at 200 rpm. After the hydrolysis is completed, the temperature is raised to 90℃ for 15 minutes to inactivate the enzyme. The mixture is first filtered through a plate and frame filter to remove large protein precipitates, then centrifuged at 5000 rpm for 15 minutes. The precipitate is washed with an equal volume of deionized water, and the supernatants are combined to obtain a hydrolyzed peptide mixture.

[0053] S2. Stepwise enzymatic hydrolysis of rice starch: Rice starch from rice milk powder was slurried to 25°Bé and stirred at 600 rpm for 20 minutes until the starch granules were completely dispersed. The pH was adjusted to 6.5 using 0.1 mol / L hydrochloric acid solution. 0.3% (by dry starch) of thermostable α-amylase was added, and the mixture was liquefied in a 95°C water bath for 60 minutes. The solution turned brownish-red when tested with iodine solution, and the DE value of the liquefied solution was 12. The temperature was raised to 100°C and held for 5 minutes to inactivate the enzyme. The temperature was lowered to 60°C, and 0.5% (by dry starch) of a mixture of glucoamylase and pullulanase (mass ratio 3:1) was added. Saccharification was carried out for 24 hours, resulting in a final DE value of 35. The temperature was raised to 90°C and held for 10 minutes to inactivate the enzyme, yielding the starch hydrolysate syrup.

[0054] S3. Flash evaporation to prepare concentrate: Mix enzymatically hydrolyzed peptide mixture and starch hydrolyzed syrup at a solids mass ratio of 1:3, adjust pH to 7.5, pump into flash evaporation equipment at a feed flow rate of 150 L / h, control feed temperature at 95℃, absolute pressure in flash chamber at 50 kPa, flash evaporation time at 10 seconds, and collect flash concentrate with a solids content of 50%.

[0055] S4. Construction and gel formation of the rice milk system: Rice milk powder passing through a 100-mesh standard sieve was mixed with deionized water at a mass ratio of 1:12. The mixture was sheared and stirred at 12000 rpm for 10 minutes, with the system temperature controlled at 30°C to form the rice milk system. 100 ppm of flash-distilled concentrate was added, and the mixture was stirred at 400 rpm for 15 minutes, followed by vacuum degassing for 10 minutes. The mixture was then sterilized at 121°C under high pressure for 15 minutes, naturally cooled to 25°C, and kept at that temperature for 2 hours to obtain a fatty-flavored starch milk carbohydrate-based gel.

[0056] In summary, the gel prepared in this embodiment has a light yellow, gel-like appearance, a thick and full texture, a rich creamy and nutty aroma, and outstanding fat simulation effect. The product exhibits excellent thermal stability; after treatment at 120℃ for 20 minutes, the fat content is retained at 89%. Adding 10% to baking fillings can completely replace 50% of the animal fat in the formula. After baking, the product retains a good oily texture and flavor profile, without drying out or becoming tough, significantly improving the sensory quality of low-fat baked goods.

[0057] Comparative Example

[0058] This comparative example uses existing conventional processes to prepare carbohydrate-based fat-substitute gels, without using a complex protease system or stepwise enzymatic hydrolysis process, and employs traditional vacuum concentration instead of short-time flash evaporation process. It is used to compare and verify the superiority of the technical solution of this invention. The specific implementation process of this comparative example is as follows:

[0059] S1. Rice protein hydrolysis: Rice milk powder is passed through an 80-mesh standard sieve. Rice protein is taken and added to deionized water at a material-to-liquid ratio of 1:7. The mixture is stirred at 400 rpm for 12 minutes until the system is homogeneous. The pH is adjusted to 7.2. Only alkaline protease is added, with the amount of enzyme added being 1.2% of the protein mass. The mixture is hydrolyzed at 52°C for 6 hours. The temperature is then raised to 90°C to inactivate the enzyme for 15 minutes. The mixture is centrifuged at 4000 rpm for 12 minutes, and the supernatant is collected to obtain the hydrolysate.

[0060] S2. Enzymatic hydrolysis of rice starch: Take rice starch from rice milk powder and adjust it to 20°Bé. Stir at 500 r / min for 18 minutes until the starch granules are completely dispersed. Adjust the pH to 6.0, add 0.2% of heat-resistant α-amylase (based on dry starch), liquefy at 92°C for 45 minutes, heat to 100°C and keep warm for 5 minutes to inactivate the enzyme, cool to 58°C, add only glucoamylase (based on dry starch) at 0.35%, saccharify for 18 hours, heat to 90°C and keep warm for 10 minutes to inactivate the enzyme, and obtain the starch hydrolysate.

[0061] S3. Vacuum concentration to prepare concentrated solution: Mix the enzymatic hydrolysate and starch hydrolysate at a solid mass ratio of 1:2, adjust the pH to 6.8, and treat with vacuum concentration at 60℃ for 30 minutes to obtain a concentrated solution with a solid content of 45%.

[0062] S4. Construction and gel formation of the rice milk system: Rice milk powder passing through an 80-mesh standard sieve was mixed with deionized water at a mass ratio of 1:10. The mixture was sheared and stirred at 10,000 rpm for 7 minutes, with the system temperature controlled at 25°C to form the rice milk system. 50 ppm of the above concentrate was added, and the mixture was stirred at 300 rpm for 12 minutes, followed by vacuum degassing for 7 minutes. The mixture was then sterilized at 121°C under high pressure for 15 minutes, naturally cooled to 25°C, and kept at that temperature for 2 hours to obtain the control gel.

[0063] In summary, the gel prepared in this comparative example has an uneven milky white appearance, contains a small amount of fine particles, has a rough and dry texture, lacks a smooth fatty feel, and has a distinct enzymatic bitterness and rancidity. The product exhibits poor thermal stability; after treatment at 120℃ for 20 minutes, the fatty feel retention rate is only 42%. When added to low-fat yogurt at a ratio of 6%, the product has a bland taste and unbalanced flavor, and its overall sensory quality is far inferior to the gel product prepared in the embodiments of this invention.

[0064] Comparison Projects Example 1 Example 2 Example 3 Comparative Example protease system Alkaline protease + flavor protease Alkaline protease + flavor protease Alkaline protease + flavor protease Alkaline protease only amylase system Thermoresistant α-amylase + glucoamylase + pullulanase Thermoresistant α-amylase + glucoamylase + pullulanase Thermoresistant α-amylase + glucoamylase + pullulanase Thermoresistant α-amylase + glucoamylase only Concentration process Short-time flash evaporation at 30 kPa for 6 seconds Short-time flash evaporation at 10 kPa for 3 seconds Short-time flash evaporation at 50 kPa for 10 seconds Vacuum concentration at 60℃ for 30 minutes Solid content of flash concentrate 45% 40% 50% 45% Fat simulates taste excellent good excellent Difference Flavor layers excellent good excellent Difference Unpleasant flavor residue none none none A distinctly bitter and rancid taste Fat retention rate at 120℃ for 20 minutes 92% 86% 89% 42% Overall sensory quality excellent good excellent Difference

[0065] The above comparisons show that the fat-flavored starch milk carbohydrate-based gels prepared in the three embodiments of this invention are significantly superior to the comparative examples in terms of product appearance, fat-simulated texture, flavor profile, and thermal stability. Example 1 uses intermediate process parameters, resulting in the best overall performance and the widest applicability; Example 2 has a light and delicate flavor, suitable for refreshing low-fat foods; Example 3 has a rich and full-bodied flavor, suitable for food systems requiring high-fat flavor. The comparative examples, due to the lack of a combined enzymatic hydrolysis and stepwise enzymatic hydrolysis process, could not generate sufficient amounts of hydrophobic peptides and compatible sugar molecules with fat-binding capabilities. Furthermore, the traditional vacuum concentration process not only retained undesirable flavors but also destroyed heat-sensitive flavor precursors, leading to a significant decline in the overall product quality. This invention, through a combination of specific enzymatic hydrolysis and short-time flash evaporation technology, effectively solves the technical defects of existing fat substitutes. The prepared gel meets clean label requirements and has broad market application prospects.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a fat-flavored starch milk carbohydrate-based gel, characterized in that, The method includes the following steps: S1. Using rice protein from rice milk powder as raw material, add deionized water at a material-to-liquid ratio of 1:5-10, adjust the pH to 6.5-8.0, add compound protease, the amount of enzyme added is 0.5%-2.0% of the protein mass, and enzymatically hydrolyze at 50-55℃ for 4-8 hours. After enzymatic hydrolysis, raise the temperature to 90℃ to inactivate the enzyme for 15 minutes, centrifuge and take the supernatant to obtain the enzymatically hydrolyzed peptide mixture. S2. Using rice starch from rice milk powder as raw material, adjust the slurry to 15-25°Bé, adjust the pH to 5.5-6.5, add heat-resistant α-amylase at a rate of 0.1%-0.3% of the dry starch, liquefy at 90-95°C for 30-60 minutes, cool to 55-60°C, add a mixed enzyme of glucoamylase and pullulanase at a rate of 0.2%-0.5% of the dry starch, and saccharify for 12-24 hours to obtain starch hydrolysate syrup. S3. Mix the enzymatically hydrolyzed peptide mixture with the starch hydrolyzed syrup at a solid mass ratio of 1:1.5-3, adjust the pH to 6.0-7.5, pump the mixture into the flash evaporator, control the feed temperature to 85-95℃, the absolute pressure of the flash evaporator to 10-50kPa, the flash evaporation time to 3-10 seconds, and collect the flash evaporation concentrate. S4. Mix rice milk powder with deionized water, and stir at high speed to form a rice milk system. Add 10-100ppm flash evaporation concentrate to the rice milk system, stir evenly, sterilize, and cool and keep warm to form a fat-flavored starch milk carbohydrate-based gel.

2. The method for preparing a fat-flavored starch milk carbohydrate-based gel according to claim 1, characterized in that, The rice milk powder used in S1 is first passed through an 80-100 mesh standard sieve to remove impurities. After adding deionized water according to the material-to-liquid ratio, the mixture is stirred at 300-500 r / min for 10-15 minutes until the system is homogeneous. The complex protease is a mixture of alkaline protease and flavor protease at a mass ratio of 2:

1. During the enzymatic hydrolysis process, the pH of the system is checked every 2 hours and maintained at 6.5-8.

0. After enzyme inactivation, the mixture is centrifuged at 3000-5000 r / min for 10-15 minutes. The molecular weight of the peptides in the resulting enzymatically hydrolyzed peptide mixture is mainly distributed between 500-3000 Da. The enzymatically hydrolyzed peptide mixture contains peptides with exposed leucine, phenylalanine, and valine residues.

3. The method for preparing a fat-flavored starch milk carbohydrate-based gel according to claim 1, characterized in that, When adding deionized water to S2 for slurry preparation, stir at 400-600 r / min for 15-20 minutes until the starch granules are completely dispersed. Add heat-resistant α-amylase for liquefaction treatment. Use the iodine test to determine the liquefaction endpoint. At the liquefaction endpoint, the iodine solution is brownish-red. Control the DE value of the liquefied solution to be 8-12. The mixed enzyme of glucoamylase and pullulanase is mixed at a mass ratio of 3:

1. The DE value is detected every 4 hours during saccharification. After the saccharification treatment, the DE value of the obtained starch hydrolysate is 25-35. The starch hydrolysate is composed of maltodextrin and oligosaccharides.

4. The method for preparing a fat-flavored starch milk carbohydrate-based gel according to claim 1, characterized in that, Before mixing the enzymatically hydrolyzed peptide mixture and the starch hydrolyzed syrup in S3, the solid content of each is measured. The amount of material to be fed is calculated according to the solid mass ratio. During mixing, the mixture is stirred at a speed of 500-700 r / min for 20-30 minutes until the system is completely homogeneous. After the material enters the flash chamber, it vaporizes instantly and the material temperature drops rapidly to 50-60℃. The vapor generated by vaporization is condensed and recovered by a condenser. During the flash evaporation process, the material is continuously fed and the flash concentrate is continuously collected. The solid content of the flash concentrate is controlled at 40%-50%.

5. The method for preparing a fat-flavored starch milk carbohydrate-based gel according to claim 1, characterized in that, The rice milk powder used in step S4 is first passed through an 80-100 mesh standard sieve. The rice milk powder and deionized water are mixed at a mass ratio of 1:8-12. The mixture is then sheared and stirred at a high speed of 8000-12000 r / min for 5-10 minutes. During the shearing process, the system temperature is controlled at 20-30℃ to form a uniform and stable rice milk system. After adding the flash evaporation concentrate to the rice milk system, the mixture is stirred at a speed of 200-400 r / min for 10-15 minutes until the flash evaporation concentrate is completely dispersed. Subsequently, vacuum degassing is performed for 5-10 minutes.

6. The method for preparing a fat-flavored starch milk carbohydrate-based gel according to claim 1, characterized in that, After the flash concentrate in S4 is completely dispersed and degassed, the system is dispensed into sterile food-grade polypropylene containers and sterilized at 121°C using a high-temperature, high-pressure rotary sterilization process for 15 minutes. After sterilization, the system is naturally cooled to 25°C and kept at 25°C for 2 hours, whereupon the system naturally forms a gel-like, fat-flavored starch milk carbohydrate-based gel.

7. The method for preparing a fat-flavored starch milk carbohydrate-based gel according to claim 1, characterized in that, In step S1, the pH of the system is adjusted to 6.5-8.0 using a 0.1 mol / L sodium hydroxide solution. During the enzymatic hydrolysis, a constant temperature water bath is used to maintain the system temperature. During the enzyme inactivation process, the system is continuously stirred at a speed of 100-200 r / min. After enzyme inactivation, the system is first filtered using a plate and frame filter to remove large molecular protein precipitates, and then centrifuged. The precipitate after centrifugation is washed once with an equal volume of deionized water and the supernatants are combined.

8. The method for preparing a fat-flavored starch milk carbohydrate-based gel according to claim 1, characterized in that, In step S2, the pH of the system is adjusted to 5.5-6.5 using a 0.1 mol / L hydrochloric acid solution. During liquefaction, the system temperature is maintained at 90-95℃ using a constant temperature water bath heating method, while the system is continuously stirred at a speed of 200-300 r / min. After liquefaction, the temperature is first raised to 100℃ and held for 5 minutes to inactivate thermoresistant α-amylase, and then lowered to 55-60℃ for saccharification. During saccharification, the same speed is maintained for continuous stirring. After saccharification, the temperature is raised to 90℃ and held for 10 minutes to inactivate saccharifying enzymes.

9. The method for preparing a fat-flavored starch milk carbohydrate-based gel according to claim 1, characterized in that, In step S3, the pH of the mixture is adjusted to 6.0-7.5 using a 0.1 mol / L sodium hydroxide solution or a 0.1 mol / L hydrochloric acid solution. The mixture is then pumped into the flash evaporator, and the feed flow rate is controlled at 50-150 L / h. The inner wall temperature is maintained within a range that does not differ from the feed temperature by more than 5°C. The vacuum degree of the flash evaporator is kept stable by a vacuum pump and a regulating valve working together.

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