High-activity Chinese yam instant tablet and preparation method thereof

Abstract

The invention provides a high-activity Chinese yam instant tablet and a preparation method thereof. Comprising the following steps: (1) raw material pretreatment: washing, peeling and slicing fresh Chinese yam, protecting color, drying, crushing, and carrying out airflow superfine grinding to obtain Chinese yam powder with high purity and uniform granularity; (3) carrying out fine treatment by adopting a colloid mill to obtain Chinese yam enzymolysis slurry, adding Chinese yam source natural phospholipid, and stirring; and (4) carrying out gradient temperature treatment. The high-quality instant Chinese yam product which is excellent in solubility, high in nutrition retention rate, pure and pleasant in flavor, fine and smooth in taste and good in storage stability is successfully prepared by constructing a multi-dimensional synergistic technical system of superfine grinding, synergistic enzymolysis, flavor regulation and control and gradient gelatinization shaping; and the quality is improved from'brewing 'to'extremely instant' and from'common food 'to'high-activity functional food'.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a highly active yam instant tablet and its preparation method. Background Technology

[0002] Yam is an important crop with both edible and medicinal properties. Its tubers are rich in active substances such as starch, mucilage polysaccharides, polysaccharides, and diosgenin. Among them, mucilage polysaccharides have the effects of enhancing immunity and protecting the gastrointestinal mucosa, while diosgenin has antioxidant and hormone metabolism regulating effects. Yam is not only a traditional Chinese medicine but also an ideal raw material for modern health foods. Its traditional processed products mainly include dried yam slices (poor rehydration), yam powder (prone to clumping and slow dissolving), yam starch (limited functionality), and fried puffed yam chips (high oil content). Although these processing methods can extend shelf life and expand the range of applications, they suffer from technical bottlenecks such as loss of nutrients, poor solubility, and rough taste due to problems such as high temperature, high oil content, or crude physical processing.

[0003] Dried yam slices are made by sun-drying or hot-air drying, with rehydration time exceeding 30 minutes and a loss of over 70% of vitamin C. Yam powder is made by directly pulverizing after drying, resulting in coarse particle size, easy clumping during preparation, dissolving time in cold water exceeding 2 minutes, and a rough texture. Yam starch, after water extraction and sedimentation, loses over 90% of its active ingredients (such as saponins and mucopolysaccharides). Fried and puffed yam chips contain over 25% oil and can produce 200-300 μg / kg of acrylamide. These traditional processes generally suffer from problems such as limited processing methods, inefficient temperature control, and unreasonable product forms, restricting the high-value utilization of yam. Therefore, developing a highly active and rapidly soluble yam product is an urgent problem to be solved. Summary of the Invention

[0004] Technical Problem to be Solved: To address the aforementioned technical problems, the purpose of this invention is to provide a high-activity yam instant tablet and its preparation method. This invention, through the construction of a multi-dimensional synergistic technology system of "ultra-micro pulverization-synergistic enzymatic hydrolysis-flavor regulation-gradient gelatinization and shaping," successfully prepares a high-quality yam instant product with excellent solubility (dissolution time ≤ 29 seconds, no precipitation), high nutrient retention rate (polysaccharide retention rate > 88%), pure and pleasant flavor, delicate and smooth texture, and good storage stability (hardness increases by only 10.2% after 2 months of storage, oxidative acid value ≤ 1.1 mg KOH / g). This achieves a quality leap from "reconstituteable" to "instantly soluble," and from "ordinary food" to "highly active functional food."

[0005] Technical solution: A method for preparing highly active yam instant tablets, comprising the following steps: Raw material pretreatment: Wash and peel fresh yam, cut into uniform thin slices with a thickness of 3-5mm, soak in compound color-protecting solution for 2-3 minutes, remove and drain water, dry at 50℃ until the moisture content drops to below 6%, pulverize to 100 mesh fineness, then air-jet pulverize to D50=13-17μm, filter through a 100 mesh sieve to obtain high-purity and uniformly sized yam powder; (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add cellulase, and react at a constant temperature of 50℃ for 40-45 minutes to reduce the viscosity of the system to below 1200 cP. Then, heat treat at 85℃ for 5 minutes to inactivate the enzyme and quickly cool to 55℃. Second stage: Adjust the pH to 4.0-4.5 with citric acid, add pectinase, and continue enzymatic hydrolysis at 50-55℃ for 30-35 minutes; Third stage: After adjusting the pH to 6.5, α-acetolactate decarboxylase and neutral protease were added simultaneously and allowed to work synergistically at 40-45℃ for 30 min. Then, the enzymes were inactivated by heat treatment at 85℃ for 5 min and cooled to room temperature. (3) Fine processing was carried out using a colloid mill, with the rotor gap set to 50 μm and three cycles performed to make the slurry particle size D90≤5 μm, to obtain yam enzymatic hydrolysate, and yam-derived natural phospholipids were added and thoroughly stirred for 5 min to ensure uniform dispersion of phospholipids; (4) Gradient temperature treatment: First, preheat at 88-92℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of amylose to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly process at a high temperature of 119-121℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 68-72℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets.

[0006] Furthermore, in step (1), the composite color-protecting liquid is composed of 0.1% citric acid and 0.1% vitamin C.

[0007] Furthermore, the conditions for airflow ultrafine pulverization in step (1) are: pulverization pressure of 0.6-0.8MPa, classifier rotation speed of 3000-4000r / min, feeding speed of 10-15 kg / h, and pulverization chamber temperature of ≤50℃.

[0008] Furthermore, in step (2), the amount of cellulase added is 0.1-0.12% of the mass of the yam powder.

[0009] Furthermore, in step (2), the amount of pectinase added is 0.08-0.1% of the mass of the yam powder.

[0010] Furthermore, in step (2), the amount of α-acetolactate decarboxylase added is 0.05-0.06% of the mass of yam powder, and the amount of neutral protease added is 0.09-0.11% of the mass of yam powder.

[0011] Furthermore, the neutral protease in step (2) is Aspergillus oryzae neutral protease.

[0012] Furthermore, in step (3), the amount of yam-derived natural phospholipids added is 0.5-0.8% of the mass of the yam enzymatic hydrolysate.

[0013] Furthermore, the preparation method of the yam-derived natural phospholipids in step (3) is as follows: S11. Wash and peel fresh yam, cut into small pieces or thin slices of 1-2cm, place in a vacuum drying oven at 40-60℃ to dry, and then pulverize into 80-120 mesh. S12. Add 95% ethanol at a solid-liquid ratio of 1:(5-10), stir and extract in a water bath at 40-50℃ for 2-3 hours, centrifuge at 3000-5000 rpm for 10-15 minutes, take the supernatant, add 2-4 times the volume of acetone, stir and let stand to precipitate, centrifuge again to collect the precipitate, and vacuum dry to obtain crude phospholipid. S13. Dissolve the crude phospholipid in a chloroform-methanol mixture at a volume ratio of 2:1, load the mixture onto a silica gel column, elute with different proportions of chloroform-methanol, collect the eluent containing the target phospholipid using a UV detector (205nm), and concentrate it to obtain yam-derived natural phospholipids.

[0014] The highly active yam instant tablets prepared by the above preparation method.

[0015] Beneficial effects: 1. This invention, through the construction of a multi-dimensional synergistic technology system of "ultra-micro pulverization-synergistic enzymatic hydrolysis-flavor regulation-gradient gelatinization and shaping", successfully prepared a high-quality instant yam product with excellent solubility (dissolution time ≤29 seconds, no precipitation), high nutrient retention rate (polysaccharide retention rate >88%), pure and pleasant flavor, delicate and smooth taste, and good storage stability (hardness increases by only 10.2% after 2 months of storage, oxidative acid value ≤1.1mg KOH / g). This invention achieves a quality leap from "reconstituteable" to "instantly soluble" and from "ordinary food" to "highly active functional food". 2. This invention achieves precise particle size control through airflow ultrafine grinding (D50=13-17μm) and filtration through a 100-mesh sieve, which greatly increases the specific surface area of ​​the material and destroys the cell wall structure, providing a solid foundation for subsequent enzymatic hydrolysis reactions and fundamentally ensuring the product's ultimate solubility and high system stability. 3. This invention employs a flavor-oriented three-stage synergistic enzymatic hydrolysis process. In the first stage, cellulase effectively breaks down the cell wall structure, significantly reducing the system viscosity (<1200 cP). In the second stage, pectinase further decomposes the intercellular matrix, increasing the free galacturonic acid content (>8 mg / g). In the third stage, an innovative dual-enzyme treatment of "ALDC-neutral protease" is used to achieve a dynamic balance of "simultaneous generation and decomposition," improving the conversion efficiency of diacetyl precursors, actively creating a fresh milky flavor, and effectively avoiding off-flavors. 4. This invention utilizes fine homogenization treatment with a colloid mill (D90≤5μm) and directional assembly technology of starch-lipid complex. By adding natural phospholipids derived from yam before gelatinization preheating, sufficient contact between phospholipids and starch molecules can be achieved before the starch granules begin to swell. During subsequent preheating and high-temperature gelatinization, the heat causes the starch granules to absorb water and swell, and the amylose escapes from the granules. Its hydrophobic helical cavity combines with the hydrophobic end of the phospholipid to form a V-shaped crystalline structure of starch-lipid complex in situ. This reduces the hardness after rehydration and effectively inhibits starch retrogradation, solving the technical problem of instant powder easily absorbing moisture and clumping. 5. This invention employs a gradient temperature control strategy of "preheating (90°C) - high-temperature gelatinization (120°C) - cooling and shaping (70°C)" to scientifically balance gelatinization efficiency and protection of heat-sensitive components, thereby increasing the degree of gelatinization to over 90% while minimizing damage to heat-sensitive components. 6. This invention effectively inhibits enzymatic browning during processing through a dual protection mechanism of a composite color-protecting liquid (0.1% citric acid + 0.1% vitamin C), ensuring product color stability and antioxidant properties. 7. The high-activity yam instant tablets of this invention have achieved breakthroughs in terms of solubility, retention of active ingredients, storage stability and sensory quality (overall score ≥91.6 points), and have comprehensively solved the technical bottlenecks of traditional plant-based instant powders such as poor solubility, easy clumping, single flavor and large nutrient loss.

[0016] Instruction manual illustrations Figure 1 This is a comparison diagram of the particle size distribution of yam powder before and after ultrafine pulverization in Example 3; Figure 2 The image shows the actual product of the highly active yam instant tablets prepared in Example 3. Detailed Implementation

[0017] This invention proposes a highly active yam instant tablet and its preparation method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following will provide a more detailed description of the invention with reference to specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0018] The cellulase used in the following examples was purchased from Novozymes (China) Biotechnology Co., Ltd., with an enzyme activity of 1000 BHU-2-HS / g; the pectinase was purchased from Xiasheng (Beijing) Biotechnology Development Co., Ltd., with an enzyme activity of 60000 u / mL; the α-acetolactate decarboxylase was purchased from Shanghai Yuanye Biotechnology Co., Ltd., catalog number S28087, with an enzyme activity of 2000 u / mL; and the Aspergillus oryzae neutral protease was purchased from Novozymes (China) Biotechnology Co., Ltd., with an enzyme activity of 0.8 AU-N / g. The yam-derived natural phospholipids can be prepared using the method in Example 1 or purchased directly.

[0019] Example 1 The preparation method of yam-derived natural phospholipids is as follows: S11. Wash and peel fresh yam, cut into small pieces or thin slices of 1-2cm, place in a vacuum drying oven at 50℃ to dry, and then pulverize into 100 mesh; S12. Add 95% ethanol at a solid-liquid ratio of 1:8, stir and extract in a water bath at 45℃ for 3 hours, centrifuge at 4000 rpm for 15 minutes, take the supernatant, add 3 times the volume of acetone, stir and let stand to precipitate, centrifuge again to collect the precipitate, and vacuum dry to obtain crude phospholipid. S13. The crude phospholipid was dissolved in a chloroform-methanol mixture at a ratio of 1:10 (g:mL) and loaded onto a 200-300 mesh silica gel-packed column. After the column bed was equilibrated with chloroform, the phospholipid solution was loaded at a flow rate of 1 mL / min. After loading, 5 column volumes of pure chloroform were used to remove neutral lipid impurities, followed by 8 column volumes of chloroform-methanol (9:1, v / v), and finally the target phospholipid was eluted with chloroform-methanol (7:3, v / v). The eluent was monitored at a wavelength of 205 nm using a UV detector throughout the process, and the eluent fractions with obvious absorption peaks were collected. The collected eluent was concentrated to near dryness by rotary evaporation at 40°C, and the residual solvent was completely removed in a vacuum drying oven at 35°C to obtain yam-derived natural phospholipids with a purity of 92.3%.

[0020] Example 2 A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5 mm, soak it in a composite color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 min, take it out and drain the water, dry it at 50℃ until the moisture content drops to 5%, grind it to 100 mesh fineness, and then air-jet pulverize it to D50=14.2μm. The conditions for air-jet pulverization are: pulverization pressure is 0.7MPa, classifier speed is 3720r / min, and feed rate is 10 kg / h. Filter it through a 100 mesh screen to remove residual fiber impurities and obtain high-purity and uniformly sized yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.11% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.09% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content is measured to be 8.2 mg / g. Third stage: After adjusting the pH to 6.5, 0.06% of α-acetolactate decarboxylase and 0.1% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzymes, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=4.5 μm, and yam enzymatic hydrolysate was obtained. 0.7% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets.

[0021] Example 3 A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5 mm, soak it in a composite color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 min, take it out and drain the water, dry it at 50℃ until the moisture content drops to 5%, grind it to 100 mesh fineness, and then air-jet pulverize it to D50=14.7μm. The conditions for air-jet pulverization are: pulverization pressure of 0.7MPa, classifying wheel speed of 3640r / min, and feeding speed of 10 kg / h. Filter it through a 100 mesh screen to remove residual fiber impurities and obtain high-purity and uniformly sized yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.11% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.09% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content is measured to be 8.2 mg / g. Third stage: After adjusting the pH to 6.5, 0.06% of α-acetolactate decarboxylase and 0.1% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzymes, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=4.6 μm, and yam enzymatic hydrolysate was obtained. 0.7% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets. Example 4

[0022] A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5 mm, soak it in a composite color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 min, take it out and drain the water, dry it at 50℃ until the moisture content drops to 5%, grind it to 100 mesh fineness, and then air-jet pulverize it to D50=15.5μm. The conditions for air-jet pulverization are: pulverization pressure is 0.7MPa, classifier speed is 3470r / min, and feed rate is 10 kg / h. Filter it through a 100 mesh screen to remove residual fiber impurities and obtain high-purity and uniformly sized yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.11% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.09% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content is measured to be 9.2 mg / g. Third stage: After adjusting the pH to 6.5, 0.06% of α-acetolactate decarboxylase and 0.1% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzymes, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=3.8 μm, and yam enzymatic hydrolysate was obtained. 0.7% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets. Example 5

[0023] A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5 mm, soak it in a composite color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 min, take it out and drain the water, dry it at 50℃ until the moisture content drops to 5%, grind it to 100 mesh fineness, and then air-jet pulverize it to D50=16.1μm. The conditions for air-jet pulverization are: pulverization pressure of 0.7MPa, classifying wheel speed of 3350r / min, and feeding speed of 10 kg / h. Filter it through a 100 mesh screen to remove residual fiber impurities and obtain high-purity and uniformly sized yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.11% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.09% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content is measured to reach 8.0 mg / g. Third stage: After adjusting the pH to 6.5, 0.06% of α-acetolactate decarboxylase and 0.1% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzymes, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=4.2 μm, and yam enzymatic hydrolysate was obtained. 0.7% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets.

[0024] Example 6 A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5 mm, soak it in a composite color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 min, take it out and drain the water, dry it at 50℃ until the moisture content drops to 5%, grind it to 100 mesh fineness, and then air-jet pulverize it to D50=14.8μm. The conditions for air-jet pulverization are: pulverization pressure of 0.7MPa, classifying wheel speed of 3640r / min, and feeding speed of 10 kg / h. Filter it through a 100 mesh screen to remove residual fiber impurities and obtain high-purity and uniformly sized yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.1% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.09% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content is measured to reach 7.5 mg / g. Third stage: After adjusting the pH to 6.5, 0.06% of α-acetolactate decarboxylase and 0.1% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzymes, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=4.6 μm, and yam enzymatic hydrolysate was obtained. 0.7% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets.

[0025] Example 7 A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5 mm, soak it in a composite color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 min, take it out and drain the water, dry it at 50℃ until the moisture content drops to 5%, grind it to 100 mesh fineness, and then air-jet pulverize it to D50=14.8μm. The conditions for air-jet pulverization are: pulverization pressure of 0.7MPa, classifying wheel speed of 3640r / min, and feeding speed of 10 kg / h. Filter it through a 100 mesh screen to remove residual fiber impurities and obtain high-purity and uniformly sized yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.12% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.09% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content is measured to be 10.2 mg / g. Third stage: After adjusting the pH to 6.5, 0.06% of α-acetolactate decarboxylase and 0.1% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzymes, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=4.6 μm, and yam enzymatic hydrolysate was obtained. 0.7% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets.

[0026] Example 8 A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5 mm, soak it in a composite color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 min, take it out and drain the water, dry it at 50℃ until the moisture content drops to 5%, grind it to 100 mesh fineness, and then air-jet pulverize it to D50=14.8μm. The conditions for air-jet pulverization are: pulverization pressure of 0.7MPa, classifying wheel speed of 3640r / min, and feeding speed of 10 kg / h. Filter it through a 100 mesh screen to remove residual fiber impurities and obtain high-purity and uniformly sized yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.11% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.08% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content is measured to be 6.7 mg / g. Third stage: After adjusting the pH to 6.5, 0.06% of α-acetolactate decarboxylase and 0.1% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzymes, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=4.6 μm, and yam enzymatic hydrolysate was obtained. 0.7% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets.

[0027] Example 9 A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5 mm, soak it in a composite color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 min, take it out and drain the water, dry it at 50℃ until the moisture content drops to 5%, grind it to 100 mesh fineness, and then air-jet pulverize it to D50=14.8μm. The conditions for air-jet pulverization are: pulverization pressure of 0.7MPa, classifying wheel speed of 3640r / min, and feeding speed of 10 kg / h. Filter it through a 100 mesh screen to remove residual fiber impurities and obtain high-purity and uniformly sized yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.11% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.1% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content is measured to be 11.0 mg / g. Third stage: After adjusting the pH to 6.5, 0.06% of α-acetolactate decarboxylase and 0.1% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzymes, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=4.6 μm, and yam enzymatic hydrolysate was obtained. 0.7% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets.

[0028] Example 10 A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5 mm, soak it in a composite color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 min, take it out and drain the water, dry it at 50℃ until the moisture content drops to 5%, grind it to 100 mesh fineness, and then air-jet pulverize it to D50=14.8μm. The conditions for air-jet pulverization are: pulverization pressure of 0.7MPa, classifying wheel speed of 3640r / min, and feeding speed of 10 kg / h. Filter it through a 100 mesh screen to remove residual fiber impurities and obtain high-purity and uniformly sized yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.11% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.09% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content is measured to be 8.2 mg / g. Third stage: After adjusting the pH to 6.5, 0.05% of α-acetolactate decarboxylase and 0.1% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzymes, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=4.6 μm, and yam enzymatic hydrolysate was obtained. 0.7% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets.

[0029] Example 11 A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5 mm, soak it in a composite color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 min, take it out and drain the water, dry it at 50℃ until the moisture content drops to 5%, grind it to 100 mesh fineness, and then air-jet pulverize it to D50=14.8μm. The conditions for air-jet pulverization are: pulverization pressure of 0.7MPa, classifying wheel speed of 3640r / min, and feeding speed of 10 kg / h. Filter it through a 100 mesh screen to remove residual fiber impurities and obtain high-purity and uniformly sized yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.11% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.09% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content is measured to be 8.2 mg / g. Third stage: After adjusting the pH to 6.5, 0.06% of α-acetolactate decarboxylase and 0.09% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzyme, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=4.6 μm, and yam enzymatic hydrolysate was obtained. 0.7% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets.

[0030] Example 12 A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut into uniform thin slices with a thickness of 3-5 mm, soak in a composite color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 min, take it out and drain the water, dry at 50℃ until the moisture content drops to 5%, grind to 100 mesh fineness, and then air-jet pulverize to D50=14.8μm. The conditions for air-jet pulverization are: pulverization pressure of 0.7MPa, classifying wheel speed of 3640r / min, and feeding speed of 10 kg / h. Filter through a 100 mesh screen to remove residual fiber impurities and obtain high-purity and uniformly sized yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.11% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.09% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content is measured to be 8.2 mg / g. Third stage: After adjusting the pH to 6.5, 0.06% of α-acetolactate decarboxylase and 0.11% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzyme, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=4.6 μm, and yam enzymatic hydrolysate was obtained. 0.7% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets.

[0031] Example 13 A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5 mm, soak it in a composite color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 min, take it out and drain the water, dry it at 50℃ until the moisture content drops to 5%, grind it to 100 mesh fineness, and then air-jet pulverize it to D50=14.8μm. The conditions for air-jet pulverization are: pulverization pressure of 0.7MPa, classifying wheel speed of 3640r / min, and feeding speed of 10 kg / h. Filter it through a 100 mesh screen to remove residual fiber impurities and obtain high-purity and uniformly sized yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.11% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.09% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content is measured to be 8.2 mg / g. Third stage: After adjusting the pH to 6.5, 0.06% of α-acetolactate decarboxylase and 0.1% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzymes, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=4.6 μm, and yam enzymatic hydrolysate was obtained. 0.5% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets.

[0032] Example 14 A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5 mm, soak it in a composite color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 min, take it out and drain the water, dry it at 50℃ until the moisture content drops to 5%, grind it to 100 mesh fineness, and then air-jet pulverize it to D50=14.8μm. The conditions for air-jet pulverization are: pulverization pressure of 0.7MPa, classifying wheel speed of 3640r / min, and feeding speed of 10 kg / h. Filter it through a 100 mesh screen to remove residual fiber impurities and obtain high-purity and uniformly sized yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.11% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.09% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content is measured to be 8.2 mg / g. Third stage: After adjusting the pH to 6.5, 0.06% of α-acetolactate decarboxylase and 0.1% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzymes, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=4.6 μm, and yam enzymatic hydrolysate was obtained. 0.8% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets.

[0033] Comparative Example 1 The difference between this comparative example and Example 3 is that the airflow ultrafine pulverization step is removed, while the other steps are the same.

[0034] A method for preparing highly active yam instant tablets includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5mm, soak it in a compound color-protecting solution composed of 0.1% citric acid and 0.1% Vc for 2 minutes, take it out and drain the water, dry it at 50℃ until the moisture content drops to 5%, and grind it to 100 mesh fineness to obtain yam powder. (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add 0.11% of cellulase by weight of yam powder, react at a constant temperature of 50℃ for 40 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.5 with citric acid, add 0.09% pectinase by weight of yam powder, and continue enzymatic hydrolysis at 55℃ for 30 min. At this time, the free galacturonic acid content was measured to be 4.1 mg / g. Third stage: After adjusting the pH to 6.5, 0.06% of α-acetolactate decarboxylase and 0.1% of Aspergillus oryzae neutral protease by weight of yam powder were added simultaneously. They were synergistically treated at 40℃ for 30 min, followed by heat treatment at 85℃ for 5 min to inactivate the enzymes, and then cooled to room temperature. (3) Fine processing was carried out using a colloid mill. The rotor gap was set to 50 μm, and three cycles were performed to make the slurry particle size D90=12.3 μm to obtain yam enzymatic hydrolysate. 0.7% of the mass of yam enzymatic hydrolysate prepared in Example 1 was added, and the mixture was stirred and mixed for 5 min to ensure that the phospholipids were evenly dispersed. (4) Gradient temperature treatment: First, preheat at 90℃ for 15s. At this time, phospholipids and starch molecules fully interact under heating conditions. Utilizing their amphiphilic properties, they intercalate with the helical cavity of the amphiphilic starch to form a starch-lipid complex with a V-shaped crystalline structure. Then, rapidly treat at 120℃ for 8s to increase the degree of gelatinization to over 90% and stabilize the structure of the formed complex. Finally, cool and set at 70℃ for 10s to form a flexible and peelable stable structure, thus obtaining high-activity yam instant tablets.

[0035] Comparative Example 2 The difference between this comparative example and Example 3 is that the three-stage synergistic enzymatic hydrolysis has been modified to simultaneous enzymatic hydrolysis, while the other steps are the same.

[0036] (1) The raw material pretreatment is the same as in Example 3; (2) Enzymatic hydrolysis steps: Mix yam powder with pure water at a ratio of 1:5, adjust the pH to 5.5, and simultaneously add 0.11% cellulase, 0.09% pectinase, 0.06% α-acetolactate decarboxylase and 0.1% Aspergillus oryzae neutral protease. Hydrolyze at a constant temperature of 50℃ for 100 min, and then cool after inactivating the enzyme at 85℃. Steps (3)-(4) are the same as in Example 3.

[0037] Comparative Example 3 The difference between this comparative example and Example 3 is that the gradient temperature treatment is replaced with isothermal treatment, while the other steps are the same.

[0038] Steps (1)-(3) are the same as in Example 3; (4) Temperature treatment: The temperature is kept constant at 120℃ for 23 seconds, without preheating and cooling.

[0039] Comparative Example 4 The difference between this comparative example and Example 3 is that the yam-derived natural phospholipids are replaced with commercially available soybean phospholipids, while the other steps are the same.

[0040] Comparative Example 5 The difference between this comparative example and Example 3 is that α-acetolactate decarboxylase is not added, while the other steps are the same.

[0041] Comparative Example 6 The difference between this comparative example and Example 3 is that there is no high-temperature treatment step, while the other steps are the same.

[0042] Steps (1)-(3) are the same as in Example 3; (4) Temperature treatment: Heat treatment at 90℃ for 23s, and then cool and set at 70℃ for 10s to obtain the product.

[0043] Performance testing: Determination of dissolution time: The "constant temperature stirring dissolution method" was used: 2.0 g of the sample to be tested was accurately weighed and added to 200 mL of deionized water at 25 °C. The sample was placed on a magnetic stirrer and stirred at a constant speed of 300 r / min. Timing was started at the same time until the sample was completely dissolved (no visible particles in the solution). The time required was recorded as the dissolution time. After dissolution, the sample was allowed to stand for 30 min. The bottom of the solution was observed for any precipitate residue, and recorded as "present / absent". Determination of coefficient of variation: Take the same batch of samples and repeat the dissolution time 10 times according to the above method, and calculate the average value. ) and standard deviation (SD), Coefficient of variation (CV%) = (SD / ) × 100%; Determination of yam polysaccharide retention rate: The phenol-sulfuric acid method was used. Equal amounts of the final product and unenzymatically hydrolyzed yam powder (as the initial standard) were accurately weighed, and after hot water extraction and alcohol precipitation, the polysaccharide content was determined according to relevant standard methods. Yam polysaccharide retention rate (%) = (polysaccharide content in the product / polysaccharide content in the initial yam powder) × 100%; The results are shown in Table 1 below: Table 1 Dissolution time (s) Coefficient of variation (%) Yam polysaccharide retention rate (%) Is there any sediment? Example 2 24 3.9 91.8 none Example 3 22 4.3 93.2 none Example 4 22 3.6 94.0 none Example 5 25 4.6 91.1 none Example 6 27 4.8 89.7 none Example 7 21 4.5 95.3 none Example 8 29 5.0 88.2 none Example 9 20 4.5 96.3 none Example 10 23 4.3 92.6 none Example 11 24 4.2 92.3 none Example 12 22 4.2 93.4 none Example 13 26 4.7 91.5 none Example 14 22 4.2 92.5 none Comparative Example 1 63 10.5 79.0 have Comparative Example 2 51 9.3 78.6 have Comparative Example 3 39 9.2 87.9 have Comparative Example 4 28 5.3 91.5 trace amounts Comparative Example 5 24 4.5 90.3 none Comparative Example 6 48 10.1 90.4 have As shown in Table 1 above, the dissolution time of all embodiments of the present invention was between 20-29 seconds, with no precipitation and a coefficient of variation of less than 5%. This demonstrates that the combination of airflow ultrafine grinding with three-stage enzymatic hydrolysis and fine homogenization significantly reduces material particle size, disrupts cell structure, and releases contents, thereby achieving excellent instant solubility and high batch stability. Comparative Example 1, which did not undergo ultrafine grinding, had the longest dissolution time (63 seconds), the highest coefficient of variation (10.5%), and precipitation. This indicates that ultrafine grinding is the most critical process for achieving the "instant dissolution" characteristic of the product; without this step, the material particle size is large, resulting in poor solubility and instability. Comparative Example 2 (single-stage enzymatic hydrolysis) and Comparative Example 6 (no high-temperature treatment) also showed significantly prolonged dissolution times and precipitation, indicating that incomplete enzymatic hydrolysis or insufficient gelatinization leads to decreased solubility. Comparative Example 4 (soybean phospholipids) showed trace precipitation, indicating that the yam-derived phospholipids have better compatibility with the system. The polysaccharide retention rate of yam in all examples was >88%, which shows that the process has a very good effect on the extraction and retention of polysaccharides, the main functional component of yam. The enzymatic hydrolysis process effectively released intracellular polysaccharides, and the subsequent treatment did not cause serious degradation. The polysaccharide retention rate of Comparative Example 1 (no ultrafine grinding) and Comparative Example 2 (single-stage enzymatic hydrolysis) was the lowest (~79%), which further confirms that the synergy of physical grinding and enzymatic hydrolysis is crucial for the effective release and retention of functional components. Without sufficient crushing and enzymatic hydrolysis, polysaccharides are trapped in the cell wall and cannot be dissolved.

[0044] In each embodiment, the yam powder was stored at 40°C and 75% humidity for 2 months. The dissolution time was measured on the 15th day, the oxidative acid value was measured after 1 month, and the hardness was measured after 2 months. Oxidative acid value (mg KOH / g): determined according to the national standard GB 5009.229-2016 "National Food Safety Standard - Determination of Acid Value in Food"; Hardness increase (%): Measured using a texture analyzer, with a flat plate probe used to measure the fracture hardness (N) of fresh products and stored samples. Hardness increase (%) = [(Hardness after storage - Initial hardness) / Initial hardness] × 100%; The results are shown in Table 2 below: Table 2 Dissolution time (s) after 15 days of storage Oxidative acid value (mg KOH / g) after 1 month of storage Hardness increased by (%) after 2 months of storage. Example 3 25 1.1 10.2 Comparative Example 1 82 2.2 35.6 Comparative Example 2 70 2.2 35.1 Comparative Example 3 53 1.6 41.6 Comparative Example 4 37 3.8 20.6 Comparative Example 5 27 1.3 11.9 Comparative Example 6 70 1.2 52.1 As shown in Table 2 above, the dissolution time of Example 3 increased slightly from 22s to 25s, but remained at a good level. In contrast, the dissolution times of all comparative examples increased significantly, especially Comparative Examples 1, 2, 3, and 6. This indicates that if the initial process is imperfect (large particle size, incomplete enzymatic hydrolysis, insufficient gelatinization), the product is more prone to moisture absorption or inter-component interactions during storage, leading to accelerated deterioration of solubility. Comparative Example 4 had the highest acid value (3.8), indicating that commercially available soybean lecithin is more prone to oxidative rancidity. Comparative Examples 1 and 2, due to incomplete component release, may contain more easily oxidized substances, hence their higher acid values. The hardness of Example 3 increased by only 10.2%, indicating that the yam powder has a stable structure and good resistance to moisture absorption and aging. This is attributed to the formation of the starch-lipid complex, which effectively reduces the rearrangement and retrogradation of starch molecules. Comparative Example 6 showed the greatest increase in hardness (52.1%) because the lack of a high-temperature gelatinization step meant that the starch was not fully gelatinized and was prone to retrogradation and hardening during storage. Comparative Example 3: The constant temperature treatment may have damaged the product structure, which also led to a significant increase in hardness (41.6%).

[0045] Sensory evaluation: A panel of 10 trained sensory evaluators conducted blind evaluations of the products in a separate sensory evaluation room. Samples were randomly numbered and scored on four dimensions: aroma (25 points), taste (25 points), color (20 points), and mouthfeel (30 points), for a total score of 100 points. The average score was taken.

[0046] Table 3 Sensory Rating Table aroma smell Color taste Total Score Example 3 22.6 22.8 18.5 27.7 91.6 Comparative Example 1 17.2 16.4 17.1 18.8 69.5 Comparative Example 2 16.1 15.8 17.6 20.2 69.7 Comparative Example 3 15.5 15.1 15.1 22.1 67.8 Comparative Example 4 17.9 18.4 17.8 25.0 79.1 Comparative Example 5 15.2 21.5 18.4 26.4 81.5 Comparative Example 6 18.5 17.0 17.9 20.5 73.9 As shown in Table 3 above, Example 3 leads by a wide margin with a score of 91.6, exhibiting the best overall sensory quality. All comparative examples scored significantly lower (67.8 - 85.6 points), indicating that the absence or substitution of any process step negatively impacts the acceptability of the final product. Regarding aroma and taste, Example 3 scored the highest, primarily due to the pleasant milky aroma (acetoin) produced by the synergistic enzymatic hydrolysis of α-acetolactate decarboxylase and neutral protease in the third stage, while avoiding off-flavors (diacetyl accumulation). Comparative Example 5 (without α-acetolactate decarboxylase) showed a decrease in flavor score, demonstrating the positive effect of ALDC on flavor. Comparative Examples 1, 2, and 3 may have a raw or cooked taste due to incomplete enzymatic hydrolysis or improper heat processing, resulting in poor flavor. In terms of color, the differences between the examples and comparative examples are relatively small, but Comparative Example 3 may have a dull color due to Maillard reaction or oxidation. In terms of taste, Example 3 scored the highest (27.7), mainly due to its excellent solubility (no grainy texture) and the smooth texture brought by the starch-lipid complex. Comparative Examples 1, 2, and 6 scored the lowest due to poor solubility, grainy texture, or sedimentation. Comparative Example 4 (soybean lecithin) had a decent taste (25 points), but it may have introduced a beany flavor, affecting the aroma and taste.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing highly active yam instant tablets, characterized in that: Includes the following steps: (1) Raw material pretreatment: Wash and peel fresh yam, cut it into uniform thin slices with a thickness of 3-5mm, soak it in the compound color protection solution for 2-3 minutes, take it out and drain the water, dry it at 50℃ until the moisture content drops to below 6%, pulverize it to 100 mesh fineness, then air-jet pulverize it to D50=13-17μm, filter it through a 100 mesh sieve to obtain high purity and uniform particle size yam powder; (2) Flavor-oriented three-stage synergistic enzymatic hydrolysis: First stage: Mix yam powder and pure water at a mass ratio of 1:5, adjust the pH of the slurry to 5.0 with citric acid, add cellulase, react at a constant temperature of 50℃ for 40-45 minutes, then heat treat at 85℃ for 5 minutes to inactivate the enzyme, and then quickly cool to 55℃. Second stage: Adjust the pH to 4.0-4.5 with citric acid, add pectinase, and continue enzymatic hydrolysis at 50-55℃ for 30-35 minutes; Third stage: After adjusting the pH to 6.5, α-acetolactate decarboxylase and neutral protease were added simultaneously and acted synergistically at 40℃ for 30 min. Then, the enzymes were inactivated by heat treatment at 85℃ for 5 min and cooled to room temperature. (3) Fine processing was carried out using a colloid mill, with the rotor gap set to 50 μm, and three cycles were performed to make the slurry particle size D90≤5 μm, to obtain yam enzymatic hydrolysate, and yam-derived natural phospholipids were added and thoroughly stirred for 5 min; (4) Gradient temperature treatment: First, preheat at 88-92℃ for 15s, then rapidly process at 119-121℃ for 8s, and finally cool and set at 68-72℃ for 10s to obtain high-activity yam instant tablets.

2. The method for preparing a highly active yam instant tablet according to claim 1, characterized in that, In step (1), the composite color-protecting liquid is composed of 0.1% citric acid and 0.1% vitamin C.

3. The method for preparing a highly active yam instant tablet according to claim 1, characterized in that, The conditions for airflow ultrafine grinding in step (1) are: grinding pressure of 0.6-0.8MPa, classifier speed of 3000-4000r / min, feeding speed of 10-15 kg / h, and grinding chamber temperature of ≤50℃.

4. The method for preparing a highly active yam instant tablet according to claim 1, characterized in that, In step (2), the amount of cellulase added is 0.1-0.12% of the mass of yam powder.

5. The method for preparing a highly active yam instant tablet according to claim 1, characterized in that, In step (2), the amount of pectinase added is 0.08-0.1% of the mass of yam powder.

6. The method for preparing a highly active yam instant tablet according to claim 1, characterized in that, In step (2), the amount of α-acetolactate decarboxylase added is 0.05-0.06% of the weight of yam powder, and the amount of neutral protease added is 0.09-0.11% of the weight of yam powder.

7. The method for preparing a highly active yam instant tablet according to claim 1, characterized in that, The neutral protease in step (2) is Aspergillus oryzae neutral protease.

8. The method for preparing a highly active yam instant tablet according to claim 1, characterized in that, In step (3), the amount of yam-derived natural phospholipids added is 0.5-0.8% of the mass of the yam enzymatic hydrolysate.

9. The method for preparing a highly active yam instant tablet according to claim 1, characterized in that, The preparation method of the yam-derived natural phospholipids in step (3) is as follows: S11. Wash and peel fresh yam, cut into small pieces or thin slices of 1-2cm, place in a vacuum drying oven at 40-60℃ to dry, and then pulverize into 80-120 mesh. S12. Add 95% ethanol at a solid-liquid ratio of 1:(5-10), stir and extract in a water bath at 40-50℃ for 2-3 hours, centrifuge at 3000-5000 rpm for 10-15 minutes, take the supernatant, add 2-4 times the volume of acetone, stir and let stand to precipitate, centrifuge again to collect the precipitate, and vacuum dry to obtain crude phospholipid. S13. Dissolve the crude phospholipid in a chloroform-methanol mixture with a volume ratio of 2:1, load the sample onto a silica gel column, elute with different proportions of chloroform-methanol, collect the eluent containing the target phospholipid using an ultraviolet detector, and concentrate it to obtain yam-derived natural phospholipids.

10. Highly active yam instant tablets prepared by the preparation method according to any one of claims 1-9.

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