Preparation process and application of lipophilic composite modified starch

Abstract

The invention belongs to the field of food additives and specifically discloses a preparation process and application of lipophilic composite modified starch; the preparation process comprises the following steps: 1) using cassava starch as a raw material, and after mechanical activation, phosphorylating and cross-linking the cassava starch to obtain phosphate-modified starch; 2) pretreating the phosphate-modified starch to obtain a pretreatment liquid, and performing three-enzyme continuous modification and denaturation on the pretreatment liquid, wherein the three-enzyme continuous modification and denaturation comprises the following steps: 21) starch branching enzyme modification and denaturation, 22) beta-amylase modification and denaturation, and 23) pullulanase modification and denaturation; the starch of the invention is modified by sodium trimetaphosphate and subjected to three-enzyme continuous modification and denaturation at the same time, thereby compensating for the defects of single enzyme modification, and the obtained product has the dual properties of cross-linked starch and esterified starch, has the advantages of good hydrophilic and lipophilic properties, high viscosity, freeze-thaw resistance, dehydration (aging) resistance, and the like, thereby making the product have better practicality.

Description

Technical Field

[0001] The invention belongs to the field of food additives and specifically discloses a preparation process of lipophilic composite modified starch and application thereof. Background Art

[0002] Starch is renewable, pollution-free, diverse, and abundant, and its physical and chemical properties vary considerably from source to source, making it widely used in industrial production. However, due to the high number of hydroxyl groups in natural starch and its high hydrophilicity, its compatibility with other lipophilic polyester polymers is generally poor, resulting in less than ideal performance in blends. Modified starch, however, has become a research focus due to its unique properties not found in natural starch.

[0003] Porous starch is a porous adsorption-rich granular material formed by treating raw starch granules with amylase. Due to its porosity and large specific surface area, porous starch can be directly prepared into a powder by adsorbing liquid or solid substances in its dry state. This process is simple and effective. Modification of porous starch primarily involves modifying the raw starch with a crosslinker followed by enzymatic degradation to produce porous starch, or esterifying and crosslinking the enzymatically degraded porous starch.

[0004] Chinese patent CN201110240157.8 discloses a method for preparing porous starch with emulsifying properties. The method uses starch as the raw material, degrades it with amylase, then crosslinks it, modifies it with hydrophobic groups, and finally degrades it with acid to synthesize a composite modified starch with both adsorption and embedding properties and emulsifying properties. The starch, after crosslinking and esterification, is washed and filtered to remove residues. After drying at room temperature, it is pulverized and sieved, and the moisture content and pH are adjusted with acid. The starch is then reacted at high temperature, maintaining its intact granular state and porous properties while undergoing a certain degree of degradation to become cold-water soluble.

[0005] However, when used in low-temperature meat products, starch is also required to have the following characteristics: the starch paste can be stored stably, the paste is resistant to high temperature and shear force, has high viscosity and good viscosity stability, and should also have high freeze-thaw stability and freezing stability, and poor paste sedimentation. The porous starch prepared by the above method has weak lipophilicity and poor freeze-thaw resistance, and cannot meet the conditions for storage, transportation, and reprocessing of low-temperature meat products, as well as the requirements for withstanding repeated freeze-thaw without changing its properties. Summary of the Invention

[0006] The present invention aims to provide a preparation process and application of lipophilic composite modified starch to solve the problems raised in the above background technology, which has good low-temperature lipophilicity and can withstand repeated freezing and thawing while still maintaining its performance.

[0007] The present invention adopts the following technical solutions:

[0008] A preparation process of lipophilic composite modified starch comprises the following steps:

[0009] 1) Using cassava starch as raw material, after mechanical activation, it is subjected to phosphorylation, cross-linking and denaturation to obtain phosphoric acid modified starch;

[0010] 2) Pre-treating the phosphate-modified starch to obtain a pre-treated liquid, and subjecting the pre-treated liquid to a three-enzyme continuous modification and denaturation process, wherein the three-enzyme continuous modification and denaturation process comprises the following steps: 21) modification and denaturation by starch branching enzyme, 22) modification and denaturation by β-amylase, and 23) modification and denaturation by pullulanase.

[0011] Furthermore, in the above-mentioned process for preparing the lipophilic composite modified starch, the mechanical activation in step 1) comprises the following steps: placing the cassava starch in an oven for drying, taking it out when the moisture content is less than 5%, and placing it in a planetary ball mill for ball milling at a ball-to-material ratio of 2-4:1, rotating at 400-600 rpm, and grinding time of 30-120 minutes; and immediately performing phosphorylation and cross-linking denaturation after taking it out.

[0012] Furthermore, in the preparation process of the above-mentioned lipophilic composite modified starch, in the step 1), a sodium trimetaphosphate aqueous solution with a sodium trimetaphosphate ratio of 4% to 10% is selected, and the mechanically activated cassava starch is added to the sodium trimetaphosphate solution with a liquid-to-solid ratio of 1:1 to 4:1, stirred and mixed, and the pH is adjusted to 10 to 12 using sodium hydroxide. The stirring is continued for 60 to 120 minutes, and the temperature is controlled at 42 to 60°C to obtain a phosphorylated cross-linked modified starch suspension. The suspension is placed in a centrifuge and centrifuged at 3000g for 10-20 minutes. The precipitate is taken, dried, and then passed through a 100-200 mesh sieve.

[0013] Furthermore, in the above-mentioned process for preparing the lipophilic composite modified starch, the pretreatment in step 2) comprises the following steps:

[0014] a. Add water to the phosphoric acid modified starch to prepare starch emulsion with a liquid-to-solid ratio of 3:1-4:1, then heat to 45-55°C and stir for 10-20 minutes;

[0015] b. High-pressure homogenization of the starch emulsion at 300-500 bar for 1-5 minutes;

[0016] c. Slowly add 10%-30% vegetable oil to the homogenized starch solution and stir evenly;

[0017] d. Perform low-frequency ultrasound on the starch solution using an intermittent ultrasonic device at 20 kHz for 30-60 seconds each time, repeating 3-6 times to obtain a pretreated solution.

[0018] Furthermore, in the preparation process of the above-mentioned lipophilic composite modified starch, the 21) starch branching enzyme modification and denaturation includes the following steps: adjusting the pH value of the pretreatment liquid to 7.0-8.0, maintaining the temperature at 47-53°C, and then adding starch branching enzyme for preliminary directional enzymatic hydrolysis for 1-2 hours, inactivating the enzyme to obtain a primary enzymatic hydrolysis solution, and the amount of starch branching enzyme added is 10-20U / mL pretreatment liquid.

[0019] Furthermore, in the preparation process of the above-mentioned lipophilic composite modified starch, the 22) β-amylase modification and denaturation includes the following steps: adjusting the pH value of the primary enzymatic hydrolysate to 5.0-7.0, maintaining the temperature at 55-60°C, and then adding β-amylase for secondary enzymatic hydrolysis for 2-3 hours, inactivating the enzyme to obtain a secondary enzymatic hydrolysate; the amount of the β-amylase added is 15-30U / mL of the primary enzymatic hydrolysate.

[0020] Furthermore, in the preparation process of the above-mentioned lipophilic composite modified starch, the pullulanase modification and denaturation comprises the following steps: adjusting the pH of the secondary enzymatic hydrolysate to 4.0-6.0 and the temperature to 60-65°C, then adding pullulanase for tertiary enzymatic hydrolysis for 2-3h, inactivating the enzyme to obtain a tertiary enzymatic hydrolysate; the amount of the pullulanase added is 10-20U / mL of the secondary enzymatic hydrolysate.

[0021] Furthermore, the preparation process of the above-mentioned lipophilic composite modified starch further includes step 3) post-treatment, comprising the following steps: centrifuging the tertiary enzymatic hydrolysate, repeatedly washing the precipitate, filtering and vacuum drying to obtain the lipophilic composite modified starch.

[0022] Furthermore, the present invention discloses a lipophilic composite modified starch, which is prepared by the above preparation process.

[0023] Furthermore, the present invention also discloses the use of the lipophilic composite modified starch in the food industry.

[0024] The present invention has the following beneficial effects:

[0025] The invention discloses a preparation process and application of lipophilic composite modified starch. Cassava starch is used as raw material, and after mechanical activation, it is subjected to phosphorylation and cross-linking denaturation to obtain phosphoric acid-modified starch. Subsequently, three enzymes are synergistically hydrolyzed and denatured, and the degree of denaturation is controlled by controlling the enzymatic hydrolysis concentration and enzymatic hydrolysis time. First, the starch branching enzyme part catalyzes the conversion of amylose into amylopectin, and then the β-amylase part is used to continuously cut off maltose from the non-reducing end of the starch, thereby reducing the length of the starch outer chain and producing β-glucan. Finally, pullulanase is used to hydrolyze the starch. The α-1,6 glycosidic bonds of β-glucan are cut in one step to form linear chains of appropriate length. The final modified starch obtained has the dual properties of cross-linked starch and esterified starch. It has the advantages of high viscosity, sol stability, and resistance to dehydration (aging), making it more practical. Especially after further mixing with chitosan and sodium alginate, its lipophilic properties at low temperatures are further enhanced, and it has good freeze-thaw resistance, making it very suitable for use in the food processing industry, especially in the field of low-temperature meat processing and transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Test Example 1: Comparison of freeze-thaw performance;

[0027] Figure 2 Test Example 1: Comparison of viscosity;

[0028] Figure 3 Test Example 1: Starch amphiphilic properties test at room temperature;

[0029] Figure 4 Test Example 1: Test of starch amphiphilic properties at low temperature;

[0030] Figure 5 Test Example 1: Aging recovery value (setback);

[0031] Figure 6 Test Example 2: Comparison of freeze-thaw performance;

[0032] Figure 7 Test Example 2: Comparison of viscosity;

[0033] Figure 8 Test Example 2: Amphiphilic properties test of starch at room temperature;

[0034] Figure 9 Test Example 2: Starch amphiphilic properties test at low temperature;

[0035] Figure 10 Test Example 2: Aging recovery value (setback). DETAILED DESCRIPTION

[0036] A preparation process of lipophilic composite modified starch comprises the following steps:

[0037] 1) Using cassava starch as raw material, after mechanical activation, it is subjected to phosphorylation, cross-linking and denaturation to obtain phosphoric acid modified starch;

[0038] 2) Pre-treating the phosphate-modified starch to obtain a pre-treated liquid, and subjecting the pre-treated liquid to a three-enzyme continuous modification and denaturation process, wherein the three-enzyme continuous modification and denaturation process comprises the following steps: 21) modification and denaturation by starch branching enzyme, 22) modification and denaturation by β-amylase, and 23) modification and denaturation by pullulanase.

[0039] The mechanical activation in step 1) comprises the following steps: placing the cassava starch in an oven for drying, taking it out when the moisture content is less than 5%, and placing it in a planetary ball mill for ball milling at a ball-to-material ratio of 2-4:1, rotating at 400-600 rpm, and grinding time of 30-120 minutes; and immediately performing phosphorylation, cross-linking and denaturation after taking it out.

[0040] In the step 1), a sodium trimetaphosphate aqueous solution containing 4% to 10% sodium trimetaphosphate is selected, and mechanically activated cassava starch is added to the sodium trimetaphosphate solution at a liquid-to-solid ratio of 1:1 to 4:1. The mixture is stirred and mixed, and the pH is adjusted to 10 to 12 using sodium hydroxide. The stirring is continued for 60 to 120 minutes, and the temperature is controlled at 42 to 60° C. to obtain a phosphorylated cross-linked modified starch suspension. The suspension is placed in a centrifuge and centrifuged at 3000 g for 10 to 20 minutes. The precipitate is collected, dried, and passed through a 100-200 mesh sieve.

[0041] The pre-treatment in the step 2) comprises the following steps:

[0042] a. Add water to the phosphoric acid modified starch to prepare starch emulsion with a liquid-to-solid ratio of 3:1-4:1, then heat to 45-55°C and stir for 10-20 minutes;

[0043] b. High-pressure homogenization of the starch emulsion at 300-500 bar for 1-5 minutes;

[0044] c. Slowly add the vegetable oil with a final mass fraction of 3%-6% into the homogenized starch solution and stir evenly;

[0045] d. Perform low-frequency ultrasound on the starch solution using an intermittent ultrasonic device at 20 kHz for 30-60 seconds each time, repeating 3-6 times to obtain a pretreated solution.

[0046] The 21) starch branching enzyme modification and denaturation comprises the following steps: adjusting the pH value of the pretreatment liquid to 7.0-8.0, maintaining the temperature at 47-53° C., then adding starch branching enzyme for preliminary directional enzymatic hydrolysis for 1-2 hours, inactivating the enzyme to obtain a primary enzymatic hydrolysis solution, and adding the starch branching enzyme in an amount of 10-20 U / mL of the pretreatment liquid.

[0047] The 22) β-amylase modification and denaturation comprises the following steps: adjusting the pH value of the primary enzymatic hydrolysis solution to 5.0-7.0 and maintaining the temperature at 55-60° C., then adding β-amylase for secondary enzymatic hydrolysis for 2-3 hours, and inactivating the enzyme to obtain a secondary enzymatic hydrolysis solution; the amount of the β-amylase added is 15-30 U / mL of the primary enzymatic hydrolysis solution.

[0048] The pullulanase modification and denaturation step 23) comprises the following steps: adjusting the pH of the secondary enzymatic hydrolysis solution to 4.0-6.0 and the temperature to 60-65° C., then adding pullulanase for tertiary enzymatic hydrolysis for 2-3 hours, and inactivating the enzyme to obtain a tertiary enzymatic hydrolysis solution; the pullulanase is added in an amount of 10-20 U / mL of the secondary enzymatic hydrolysis solution.

[0049] The method further comprises step 3) post-treatment, which comprises the following steps: centrifuging the tertiary enzymatic hydrolysate, repeatedly washing the precipitate, filtering it, and vacuum drying it to obtain lipophilic composite modified starch.

[0050] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0051] The reagents in the present invention were all purchased from the open market.

[0052] Chitosan was purchased from Guangzhou Hewei Pharmaceutical Technology Co., Ltd. with the product number CD107335, and the degree of deacetylation was >90%.

[0053] The starch branching enzyme is commercially purchased or produced from the starch branching enzyme mutant described in CN202110887864.X.

[0054] Example 1

[0055] A preparation process of lipophilic composite modified starch comprises the following steps:

[0056] 1) Using cassava starch as raw material, after mechanical activation, it is subjected to phosphorylation, cross-linking and denaturation to obtain phosphoric acid modified starch;

[0057] 2) Pre-treating the phosphate-modified starch to obtain a pre-treated liquid, and subjecting the pre-treated liquid to a three-enzyme continuous modification and denaturation process, wherein the three-enzyme continuous modification and denaturation process comprises the following steps: 21) modification and denaturation by starch branching enzyme, 22) modification and denaturation by β-amylase, and 23) modification and denaturation by pullulanase.

[0058] The mechanical activation in step 1) comprises the following steps: placing the cassava starch in an oven for drying, taking it out when the moisture content is less than 5%, and placing it in a planetary ball mill for ball milling at a ball-to-material ratio of 2:1, rotating at 400 rpm, and grinding for 30 minutes; and immediately performing phosphorylation and cross-linking denaturation after taking it out.

[0059] In the step 1), a sodium trimetaphosphate aqueous solution containing 4% sodium trimetaphosphate is selected, and mechanically activated cassava starch is added to the sodium trimetaphosphate solution at a liquid-to-solid ratio of 1:1. The mixture is stirred and mixed, and the pH is adjusted to 10 using sodium hydroxide. The stirring is continued for 60 minutes, and the temperature is controlled at 42° C. to obtain a phosphorylated cross-linked modified starch suspension. The suspension is placed in a centrifuge and centrifuged at 3000 g for 10 minutes. The precipitate is taken, dried, and passed through a 100-200 mesh sieve;

[0060] The pre-treatment in the step 2) comprises the following steps:

[0061] a. Add water to the phosphoric acid-modified starch to prepare a starch emulsion with a liquid-to-solid ratio of 3:1, then heat to 45°C and stir for 10 minutes;

[0062] b. The starch emulsion was subjected to high pressure homogenization at 300 bar for 1 min;

[0063] c. Slowly add corn oil with a final mass fraction of 3% into the homogenized starch solution and stir evenly;

[0064] d. The starch solution was subjected to low-frequency ultrasound using an intermittent ultrasonic device at 20 kHz for 30 seconds each time, repeated three times to obtain a pretreated solution.

[0065] The 21) starch branching enzyme modification and denaturation comprises the following steps: adjusting the pH value of the pretreatment liquid to 7.0, maintaining the temperature at 47° C., then adding starch branching enzyme for preliminary directional enzymatic hydrolysis for 1 hour, inactivating the enzyme to obtain a primary enzymatic hydrolysis solution, and adding the starch branching enzyme in an amount of 10 U / mL pretreatment liquid.

[0066] The 22) β-amylase modification and denaturation comprises the following steps: adjusting the pH value of the primary enzymatic hydrolysis solution to 5.0 and maintaining the temperature at 55° C., then adding β-amylase for secondary enzymatic hydrolysis for 2 hours, and inactivating the enzyme to obtain a secondary enzymatic hydrolysis solution; the amount of the β-amylase added is 15 U / mL of the primary enzymatic hydrolysis solution.

[0067] The pullulanase modification and denaturation step 23) comprises the following steps: adjusting the pH of the secondary enzymatic hydrolysis solution to 4.0 and the temperature to 60° C., then adding pullulanase for tertiary enzymatic hydrolysis for 2 h, and inactivating the enzyme to obtain a tertiary enzymatic hydrolysis solution; the pullulanase is added in an amount of 10 U / mL of the secondary enzymatic hydrolysis solution.

[0068] The method further comprises step 3) post-treatment, which comprises the following steps: centrifuging the tertiary enzymatic hydrolysate, washing the precipitate to neutrality, filtering it, and vacuum drying it to obtain lipophilic composite modified starch.

[0069] Example 2

[0070] A preparation process of lipophilic composite modified starch comprises the following steps:

[0071] 1) Using cassava starch as raw material, after mechanical activation, it is subjected to phosphorylation, cross-linking and denaturation to obtain phosphoric acid modified starch;

[0072] 2) Pre-treating the phosphate-modified starch to obtain a pre-treated liquid, and subjecting the pre-treated liquid to a three-enzyme continuous modification and denaturation process, wherein the three-enzyme continuous modification and denaturation process comprises the following steps: 21) modification and denaturation by starch branching enzyme, 22) modification and denaturation by β-amylase, and 23) modification and denaturation by pullulanase.

[0073] The mechanical activation in step 1) comprises the following steps: placing the cassava starch in an oven for drying, taking it out when the moisture content is less than 5%, and placing it in a planetary ball mill for ball milling at a ball-to-material ratio of 3:1, rotating at 500 rpm, and grinding for 60 minutes; and immediately performing phosphorylation and cross-linking denaturation after taking it out.

[0074] In the step 1), a sodium trimetaphosphate aqueous solution containing 8% sodium trimetaphosphate is selected, and mechanically activated cassava starch is added to the sodium trimetaphosphate solution at a liquid-to-solid ratio of 2:1. The mixture is stirred and mixed, and the pH is adjusted to 11 using sodium hydroxide. The stirring is continued for 90 minutes, and the temperature is controlled at 50° C. to obtain a phosphorylated cross-linked modified starch suspension. The suspension is placed in a centrifuge and centrifuged at 3000 g for 15 minutes. The precipitate is collected, dried, and passed through a 100-200 mesh sieve.

[0075] The pre-treatment in the step 2) comprises the following steps:

[0076] a. Add water to the phosphoric acid-modified starch to prepare a starch emulsion with a liquid-to-solid ratio of 3.5:1, then heat to 50°C and stir for 15 minutes;

[0077] b. The starch emulsion was subjected to high pressure homogenization at 400 bar for 3 min;

[0078] c. Slowly add peanut oil with a final mass fraction of 5% into the homogenized starch solution and stir evenly;

[0079] d. The starch solution was subjected to low-frequency ultrasound using an intermittent ultrasonic device at 20 kHz for 45 seconds each time, repeated 4 times to obtain a pretreated solution.

[0080] The 21) starch branching enzyme modification and denaturation comprises the following steps: adjusting the pH value of the pretreatment liquid to 7.5, maintaining the temperature at 50°C, then adding starch branching enzyme for preliminary directional enzymatic hydrolysis for 1.5 hours, inactivating the enzyme to obtain a primary enzymatic hydrolysis solution, and adding the starch branching enzyme in an amount of 15 U / mL pretreatment liquid.

[0081] The 22) β-amylase modification and denaturation comprises the following steps: adjusting the pH value of the primary enzymatic hydrolysis solution to 6.0 and maintaining the temperature at 57° C., then adding β-amylase for secondary enzymatic hydrolysis for 2.5 hours, and inactivating the enzyme to obtain a secondary enzymatic hydrolysis solution; the amount of the β-amylase added is 20 U / mL of the primary enzymatic hydrolysis solution.

[0082] The pullulanase modification and denaturation step 23) comprises the following steps: adjusting the pH of the secondary enzymatic hydrolysis solution to 5.0 and the temperature to 63° C., then adding pullulanase for tertiary enzymatic hydrolysis for 2.5 h, and inactivating the enzyme to obtain a tertiary enzymatic hydrolysis solution; the pullulanase is added in an amount of 15 U / mL of the secondary enzymatic hydrolysis solution.

[0083] The method further comprises step 3) post-treatment, which comprises the following steps: centrifuging the tertiary enzymatic hydrolysate, washing the precipitate to neutrality, filtering it, and vacuum drying it to obtain lipophilic composite modified starch.

[0084] Example 3

[0085] A preparation process of lipophilic composite modified starch comprises the following steps:

[0086] 1) Using cassava starch as raw material, after mechanical activation, it is subjected to phosphorylation, cross-linking and denaturation to obtain phosphoric acid modified starch;

[0087] 2) Pre-treating the phosphate-modified starch to obtain a pre-treated liquid, and subjecting the pre-treated liquid to a three-enzyme continuous modification and denaturation process, wherein the three-enzyme continuous modification and denaturation process comprises the following steps: 21) modification and denaturation by starch branching enzyme, 22) modification and denaturation by β-amylase, and 23) modification and denaturation by pullulanase.

[0088] The mechanical activation in step 1) comprises the following steps: placing the cassava starch in an oven for drying, taking it out when the moisture content is less than 5%, and placing it in a planetary ball mill for ball milling at a ball-to-material ratio of 4:1, rotating at 600 rpm, and grinding for 120 minutes; and immediately performing phosphorylation and cross-linking denaturation after taking it out.

[0089] In the step 1), a sodium trimetaphosphate aqueous solution containing 10% sodium trimetaphosphate is selected, and mechanically activated cassava starch is added to the sodium trimetaphosphate solution at a liquid-to-solid ratio of 4:1. The mixture is stirred and mixed, and the pH is adjusted to 12 using sodium hydroxide. The stirring is continued for 120 minutes, and the temperature is controlled at 60° C. to obtain a phosphorylated cross-linked modified starch suspension. The suspension is placed in a centrifuge and centrifuged at 3000 g for 20 minutes. The precipitate is collected, dried, and passed through a 100-200 mesh sieve.

[0090] The pre-treatment in the step 2) comprises the following steps:

[0091] a. Add water to the phosphoric acid-modified starch to prepare a starch emulsion with a liquid-to-solid ratio of 4:1, then heat to 55°C and stir for 20 minutes;

[0092] b. High-pressure homogenization of the starch emulsion at 300-500 bar for 5 minutes;

[0093] c. Slowly add sunflower oil with a final mass fraction of 6% into the homogenized starch solution and stir evenly;

[0094] d. The starch solution was subjected to low-frequency ultrasound using an intermittent ultrasonic device at 20 kHz for 60 seconds each time, repeated 6 times to obtain a pretreated solution.

[0095] The 21) starch branching enzyme modification and denaturation comprises the following steps: adjusting the pH value of the pretreatment liquid to 8.0, maintaining the temperature at 53° C., then adding starch branching enzyme for preliminary directional enzymatic hydrolysis for 2 hours, inactivating the enzyme to obtain a primary enzymatic hydrolysis solution, and adding the starch branching enzyme in an amount of 20 U / mL of the pretreatment liquid.

[0096] The 22) β-amylase modification and denaturation comprises the following steps: adjusting the pH value of the primary enzymatic hydrolysis solution to 7.0 and maintaining the temperature at 60° C., then adding β-amylase for secondary enzymatic hydrolysis for 3 hours, and inactivating the enzyme to obtain a secondary enzymatic hydrolysis solution; the amount of the β-amylase added is 30 U / mL of the primary enzymatic hydrolysis solution.

[0097] The pullulanase modification and denaturation step 23) comprises the following steps: adjusting the pH of the secondary enzymatic hydrolysis solution to 6.0 and the temperature to 65° C., then adding pullulanase for tertiary enzymatic hydrolysis for 3 hours, and inactivating the enzyme to obtain a tertiary enzymatic hydrolysis solution; the pullulanase is added in an amount of 20 U / mL of the secondary enzymatic hydrolysis solution.

[0098] The method further comprises step 3) post-treatment, which comprises the following steps: centrifuging the tertiary enzymatic hydrolysate, washing the precipitate to neutrality, filtering it, and vacuum drying it to obtain lipophilic composite modified starch.

[0099] Example 4

[0100] A preparation process of lipophilic composite modified starch comprises the following steps:

[0101] 1) Using cassava starch as raw material, after mechanical activation, it is subjected to phosphorylation, cross-linking and denaturation to obtain phosphoric acid modified starch;

[0102] 2) Pre-treating the phosphate-modified starch to obtain a pre-treated liquid, and subjecting the pre-treated liquid to a three-enzyme continuous modification and denaturation process, wherein the three-enzyme continuous modification and denaturation process comprises the following steps: 21) modification and denaturation by starch branching enzyme, 22) modification and denaturation by β-amylase, and 23) modification and denaturation by pullulanase.

[0103] The mechanical activation in step 1) comprises the following steps: placing the cassava starch in an oven for drying, taking it out when the moisture content is less than 5%, and placing it in a planetary ball mill for ball milling at a ball-to-material ratio of 3:1, rotating at 500 rpm, and grinding for 60 minutes; and immediately performing phosphorylation and cross-linking denaturation after taking it out.

[0104] In the step 1), a sodium trimetaphosphate aqueous solution containing 8% sodium trimetaphosphate is selected, and mechanically activated cassava starch is added to the sodium trimetaphosphate solution at a liquid-to-solid ratio of 2:1. The mixture is stirred and mixed, and the pH is adjusted to 11 using sodium hydroxide. The stirring is continued for 90 minutes, and the temperature is controlled at 50° C. to obtain a phosphorylated cross-linked modified starch suspension. The suspension is placed in a centrifuge and centrifuged at 3000 g for 15 minutes. The precipitate is collected, dried, and passed through a 100-200 mesh sieve.

[0105] The pre-treatment in the step 2) comprises the following steps:

[0106] a. Add water to the phosphoric acid-modified starch to prepare a starch emulsion with a liquid-to-solid ratio of 3.5:1, then heat to 50°C and stir for 15 minutes;

[0107] b. The starch emulsion was subjected to high pressure homogenization at 400 bar for 3 min;

[0108] c. Slowly add peanut oil with a final mass fraction of 5% into the homogenized starch solution and stir evenly;

[0109] d. The starch solution was subjected to low-frequency ultrasound using an intermittent ultrasonic device at 20 kHz for 45 seconds each time, repeated 4 times to obtain a pretreated solution.

[0110] The 21) starch branching enzyme modification and denaturation comprises the following steps: adjusting the pH value of the pretreatment liquid to 7.5, maintaining the temperature at 50°C, then adding starch branching enzyme for preliminary directional enzymatic hydrolysis for 1.5 hours, inactivating the enzyme to obtain a primary enzymatic hydrolysis solution, and adding the starch branching enzyme in an amount of 15 U / mL pretreatment liquid.

[0111] The 22) β-amylase modification and denaturation comprises the following steps: adjusting the pH value of the primary enzymatic hydrolysis solution to 6.0 and maintaining the temperature at 57° C., then adding β-amylase for secondary enzymatic hydrolysis for 2.5 hours, and inactivating the enzyme to obtain a secondary enzymatic hydrolysis solution; the amount of the β-amylase added is 20 U / mL of the primary enzymatic hydrolysis solution.

[0112] The pullulanase modification and denaturation step 23) comprises the following steps: adjusting the pH of the secondary enzymatic hydrolysis solution to 5.0 and the temperature to 63° C., then adding pullulanase for tertiary enzymatic hydrolysis for 2.5 h, and inactivating the enzyme to obtain a tertiary enzymatic hydrolysis solution; the pullulanase is added in an amount of 15 U / mL of the secondary enzymatic hydrolysis solution.

[0113] The method further includes step 3) post-processing, comprising the following steps: adding a final mass fraction of 3% dry powder of a mixture of chitosan and sodium alginate to the third-stage enzymatic hydrolysate, stirring the solution, centrifuging the solution, washing the precipitate to neutrality, filtering, and vacuum drying to obtain a lipophilic composite modified starch;

[0114] The mass ratio of the chitosan to sodium alginate is 2:1.

[0115] Example 5

[0116] A preparation process of lipophilic composite modified starch comprises the following steps:

[0117] 1) Using cassava starch as raw material, after mechanical activation, it is subjected to phosphorylation, cross-linking and denaturation to obtain phosphoric acid modified starch;

[0118] 2) Pre-treating the phosphate-modified starch to obtain a pre-treated liquid, and subjecting the pre-treated liquid to a three-enzyme continuous modification and denaturation process, wherein the three-enzyme continuous modification and denaturation process comprises the following steps: 21) modification and denaturation by starch branching enzyme, 22) modification and denaturation by β-amylase, and 23) modification and denaturation by pullulanase.

[0119] The mechanical activation in step 1) comprises the following steps: placing the cassava starch in an oven for drying, taking it out when the moisture content is less than 5%, and placing it in a planetary ball mill for ball milling at a ball-to-material ratio of 3:1, rotating at 500 rpm, and grinding for 60 minutes; and immediately performing phosphorylation and cross-linking denaturation after taking it out.

[0120] In the step 1), a sodium trimetaphosphate aqueous solution containing 8% sodium trimetaphosphate is selected, and mechanically activated cassava starch is added to the sodium trimetaphosphate solution at a liquid-to-solid ratio of 2:1. The mixture is stirred and mixed, and the pH is adjusted to 11 using sodium hydroxide. The stirring is continued for 90 minutes, and the temperature is controlled at 50° C. to obtain a phosphorylated cross-linked modified starch suspension. The suspension is placed in a centrifuge and centrifuged at 3000 g for 15 minutes. The precipitate is collected, dried, and passed through a 100-200 mesh sieve.

[0121] The pre-treatment in the step 2) comprises the following steps:

[0122] a. Add water to the phosphoric acid-modified starch to prepare a starch emulsion with a liquid-to-solid ratio of 3.5:1, then heat to 50°C and stir for 15 minutes;

[0123] b. The starch emulsion was subjected to high pressure homogenization at 400 bar for 3 min;

[0124] c. Slowly add peanut oil with a final mass fraction of 5% into the homogenized starch solution and stir evenly;

[0125] d. The starch solution was subjected to low-frequency ultrasound using an intermittent ultrasonic device at 20 kHz for 45 seconds each time, repeated 4 times to obtain a pretreated solution.

[0126] The 21) starch branching enzyme modification and denaturation comprises the following steps: adjusting the pH value of the pretreatment liquid to 7.5, maintaining the temperature at 50°C, then adding starch branching enzyme for preliminary directional enzymatic hydrolysis for 1.5 hours, inactivating the enzyme to obtain a primary enzymatic hydrolysis solution, and adding the starch branching enzyme in an amount of 15 U / mL pretreatment liquid.

[0127] The 22) β-amylase modification and denaturation comprises the following steps: adjusting the pH value of the primary enzymatic hydrolysis solution to 6.0 and maintaining the temperature at 57° C., then adding β-amylase for secondary enzymatic hydrolysis for 2.5 hours, and inactivating the enzyme to obtain a secondary enzymatic hydrolysis solution; the amount of the β-amylase added is 20 U / mL of the primary enzymatic hydrolysis solution.

[0128] The pullulanase modification and denaturation step 23) comprises the following steps: adjusting the pH of the secondary enzymatic hydrolysis solution to 5.0 and the temperature to 63° C., then adding pullulanase for tertiary enzymatic hydrolysis for 2.5 h, and inactivating the enzyme to obtain a tertiary enzymatic hydrolysis solution; the pullulanase is added in an amount of 15 U / mL of the secondary enzymatic hydrolysis solution.

[0129] The method further includes step 3) post-processing, comprising the following steps: adding a final mass fraction of 3% dry powder of a mixture of chitosan and sodium alginate to the third-stage enzymatic hydrolysate, stirring the solution, centrifuging the solution, washing the precipitate to neutrality, filtering, and vacuum drying to obtain a lipophilic composite modified starch;

[0130] The mass ratio of the chitosan to sodium alginate is 1:1.

[0131] Test Example 1

[0132] Performance test of the lipophilic composite modified starch prepared in Examples 1-5

[0133] 1) Freeze-thaw test

[0134] The starch paste used in frozen foods needs to be frozen at low temperatures, or the food can still maintain its original texture after multiple freezing and thawing. The more times the starch paste is frozen and thawed, the better its freeze-thaw stability, and the more suitable it is for low-temperature thickening. Freeze-thaw stability test: Add water to the sample to make a 3% (mass percentage) starch milk, heat it in boiling water for 20 minutes, fully gelatinize it, cool it, take 30 ml of it and add it to a plastic cup, cover it, and freeze it in a -18°C refrigerator for 24 hours. Take it out and thaw it naturally at room temperature, observe the condition of the paste, and then repeat several times until the colloidal structure of the paste is destroyed, clear water precipitates and it becomes spongy, and record the number of thawing times. The more freeze-thaw stability the product has, the better its application performance as a food additive. The results are shown in Tables 1 and Figure 1 .

[0135] Table 1 Test Example 1: Freeze-thaw performance

[0136] Freeze-thaw stability times Example 1 18 Example 2 21 Example 3 20 Example 4 27 Example 5 24

[0137] As can be seen from Table 1, the starch prepared using the technical solution of the present invention has good freeze-thaw resistance, especially after adding a final mass fraction of 3% of chitosan and sodium alginate mixture powder after the three enzymatic hydrolysis solutions, its freeze-thaw resistance is improved by more than 20%.

[0138] 2) Viscosity

[0139] Starch and water were mixed at a starch:water ratio of 1:5 (mass ratio), stirred at a speed of 1400 rpm for 1 h, 80 ml of the sample was taken out and placed in a 100 ml beaker, and the temperature was lowered to 25°C; the viscosity was measured using a DV digital viscometer, with rotor No. 3 selected and a speed of 12 r / min to measure the viscosity of the starch adhesive after dissolution.

[0140] The results are shown in Table 2 and Figure 2

[0141] Table 2 Test Example 1: Viscosity

[0142] Viscosity (mPa.s) Example 1 230 Example 2 235 Example 3 245 Example 4 252 Example 5 255

[0143] As can be seen from Table 2, the starch prepared using the technical solution of the present invention has good viscosity. After adding the dry powder of the chitosan and sodium alginate mixture after the three enzymatic hydrolysis solutions, the viscosity is further improved.

[0144] 3) Amphiphilicity test

[0145] Determination of water absorption and oil absorption at room temperature: 10.0 g (absolutely dry) of the final product prepared in Examples 1 to 5 was accurately weighed and placed in a 250 ml beaker. 50 ml of distilled water or salad oil was added and mixed in a 25°C water bath for 30 min. The mixture was filtered using a constant weight G4 sand core funnel until no water or oil drops were left. The water absorption and oil absorption were then weighed and calculated. The results are shown in Tables 3 and Figure 3 .

[0146] Table 3 Test Example 1: Starch amphiphilic properties test at room temperature

[0147] Water absorption (%) Oil absorption rate (%) Example 1 122 128 Example 2 115 131 Example 3 121 125 Example 4 125 134 Example 5 126 129

[0148] It can be seen from the data in Table 3 that the starch prepared by the technical solution of the present invention has good amphiphilic properties at room temperature.

[0149] Determination of water absorption and oil absorption at low temperature: 10.0 g (absolutely dry) of the final product prepared in Examples 1 to 5 was accurately weighed and placed in a 250 ml beaker. 50 ml of distilled water or salad oil was added and mixed in a 4°C water bath for 30 min. The mixture was filtered using a constant weight G4 sand core funnel until no water or oil drops were left. The water absorption and oil absorption were then weighed and calculated. The results are shown in Tables 4 and Figure 4 .

[0150] Table 4 Test Example 1: Test of starch amphiphilic properties at low temperature

[0151] Water absorption (%) Oil absorption rate (%) Example 1 112 118 Example 2 114 114 Example 3 110 115 Example 4 114 123 Example 5 116 118

[0152] From the data in Table 4, it can be seen that the starch prepared by the technical solution of the present invention has good amphiphilic properties even at low temperatures, which is only slightly lower than that at room temperature. In particular, after adding the dry powder of the chitosan and sodium alginate mixture after the three enzymatic hydrolysis solutions, the amphiphilic properties are further improved.

[0153] 4) During the storage process of gelatinized starch, the hardening phenomenon caused by the continuous association of hydrogen bonds between molecular chains is called starch aging or retrogradation. The determination of the aging recovery value index is completed by a rapid viscosity tester (RVA). The specific process is as follows: the sample is placed in the rapid viscosity tester, heated from the initial temperature to 50°C, kept for 60 seconds, then heated from 50°C to 95°C (heating rate of 0.22°C per second), kept at 95°C for 150 seconds, and finally cooled to the final temperature and kept for 120 seconds. After the measurement, the corresponding experimental data are obtained, including the peak viscosity, final viscosity, breakdown value and aging recovery value. The higher the aging recovery value, the less aging resistance it has. The results are shown in Tables 5 and Figure 5 .

[0154] Table 5 Test Example 1: Aging recovery value (setback)

[0155] Aging recovery value (setback) Example 1 32 Example 2 28 Example 3 25 Example 4 20 Example 5 18

[0156] From the data in Table 5, it can be seen that the starch prepared by the technical solution of the present invention has good anti-aging performance, and after adding the dry powder of the mixture of chitosan and sodium alginate, it has even better anti-aging ability.

[0157] Comparative Example 1

[0158] Tapioca starch

[0159] Comparative Example 2

[0160] Cassava starch was used for enzymatic hydrolysis without modification, and the rest was the same as in Example 4.

[0161] Comparative Example 3

[0162] The modification and enzymatic hydrolysis of cassava starch were carried out without mechanical activation, and the rest was the same as in Example 4.

[0163] Comparative Example 4

[0164] The modification steps were the same as those in Example 4, except for one enzymatic hydrolysis step, excluding the second and third enzymatic hydrolysis steps. The rest were the same as those in Example 4.

[0165] Comparative Example 5

[0166] The modification steps were the same as those in Example 4, using a two-step enzymatic hydrolysis process, excluding the third step enzymatic hydrolysis, and the rest were the same as those in Example 4.

[0167] Test Example 2

[0168] The starches prepared in Example 4 and Comparative Examples 1-5 were subjected to performance tests.

[0169] 1) Freeze-thaw test

[0170] The starch paste used in frozen food needs to be frozen at low temperature, or frozen and thawed multiple times.

[0171] The more times the starch paste is frozen and thawed, the better its freeze-thaw stability is, and the more suitable it is for low-temperature thickening.

[0172] Freeze-thaw stability test: Add water to the sample to make 3% (mass percentage) starch milk, heat in boiling water for 20 minutes, fully gelatinize, cool, take 30ml of it and add it to a plastic cup, cover it, and freeze it in a -18℃ refrigerator for 24 hours. Take it out and thaw it naturally at room temperature, observe the paste, and then repeat several times until the colloidal structure of the paste is destroyed and clear water precipitates and becomes spongy. Record the number of thawing times. The more freeze-thaw stability times the product has, the better its application performance as a food additive. The results are shown in Table 6 and Figure 6 .

[0173] Table 6 Test Example 2: Freeze-thaw performance

[0174] Freeze-thaw stability times Example 4 27 Comparative Example 1 9 Comparative Example 2 15 Comparative Example 3 23 Comparative Example 4 20 Comparative Example 5 17

[0175] As can be seen from Table 6, the starch prepared using the technical solution of the present invention (Example 4) has good freeze-thaw performance, which is more than 3 times higher than the 9 times of the original cassava starch. From Comparative Examples 2 and 3, modification before enzymatic hydrolysis, especially mechanical activation, is beneficial to the enzymatic hydrolysis. From Comparative Examples 4 and 5, it can be seen that the three-step enzymatic hydrolysis has better anti-freeze-thaw performance than the 1- and 2-step enzymatic hydrolysis, indicating that the starch disclosed in the present invention is more suitable for use in low-temperature food processing and transportation.

[0176] 2) Viscosity

[0177] Starch and water were mixed at a starch:water ratio of 1:5 (mass ratio), stirred at a speed of 1400 rpm for 1 h, 80 ml of the sample was taken out and placed in a 100 ml beaker, and the temperature was lowered to 25°C; the viscosity was measured using a DV digital viscometer, with rotor No. 3 selected and a speed of 12 r / min to measure the viscosity of the starch adhesive after dissolution.

[0178] The results are shown in Table 7 and Figure 7

[0179] Table 7 Test Example 2: Viscosity

[0180] Viscosity (mPa.s) Example 4 252 Comparative Example 1 200 Comparative Example 2 220 Comparative Example 3 233 Comparative Example 4 212 Comparative Example 5 214

[0181] As can be seen from Table 7, the starch prepared using the technical solution of the present invention (Example 4) has good viscosity. After the original cassava starch (Comparative Example 1) is modified and enzymatically hydrolyzed and the dry powder of the chitosan and sodium alginate mixture is added, the viscosity increases by more than 20%.

[0182] 3) Amphiphilicity test

[0183] Determination of water absorption and oil absorption at room temperature: 10.0 g (absolutely dry) of the final product prepared in Examples 1 to 5 was accurately weighed and placed in a 250 ml beaker. 50 ml of distilled water or salad oil was added and mixed in a 25°C water bath for 30 min. The mixture was filtered using a constant weight G4 sand core funnel until no water or oil drops were left. The water absorption and oil absorption were then weighed and calculated. The results are shown in Tables 8 and Figure 8 .

[0184] Table 8 Test Example 2: Starch amphiphilic properties test at room temperature

[0185] Water absorption (%) Oil absorption rate (%) Example 4 125 134 Comparative Example 1 128 65 Comparative Example 2 121 89 Comparative Example 3 127 124 Comparative Example 4 119 104 Comparative Example 5 112 110

[0186] From the data in Table 8, it can be seen that the starch prepared by the technical solution of the present invention (Example 4) has good amphiphilic properties at room temperature. After modification and enzymatic hydrolysis and the addition of chitosan and sodium alginate mixture powder, the lipophilicity of the original cassava starch (Comparative Example 1) increases by more than 100%.

[0187] Determination of water absorption and oil absorption at low temperature: 10.0 g (absolutely dry) of the final product prepared in Examples 1 to 5 was accurately weighed and placed in a 250 ml beaker. 50 ml of distilled water or salad oil was added and mixed in a 4°C water bath for 30 min. The mixture was filtered using a constant weight G4 sand core funnel until no water or oil drops were left. The water absorption and oil absorption were then weighed and calculated. The results are shown in Tables 9 and Figure 9 .

[0188] Table 9 Test Example 2: Test of starch amphiphilic properties at low temperature

[0189] Water absorption (%) Oil absorption rate (%) Example 4 114 123 Comparative Example 1 99 33 Comparative Example 2 102 88 Comparative Example 3 112 110 Comparative Example 4 89 85 Comparative Example 5 95 92

[0190] As can be seen from the data in Table 9, the starch prepared by the technical solution of the present invention (Example 4) also has good amphiphilic properties at low temperatures. After the original cassava starch (Comparative Example 1) is modified and enzymatically hydrolyzed and the dry powder of the chitosan and sodium alginate mixture is added, the low-temperature lipophilicity increases by more than 200%, indicating that the starch disclosed in the present invention is more suitable for addition to meat products at low temperatures.

[0191] 4) During the storage process of gelatinized starch, the hardening phenomenon caused by the continuous association of hydrogen bonds between molecular chains is called starch aging or retrogradation. The determination of the aging recovery value index is completed by a rapid viscosity tester (RVA). The specific process is as follows: the sample is placed in the rapid viscosity tester, heated from the initial temperature to 50°C, kept for 60 seconds, then heated from 50°C to 95°C (heating rate of 0.22°C per second), kept at 95°C for 150 seconds, and finally cooled to the final temperature and kept for 120 seconds. After the determination, the corresponding experimental data are obtained, including the peak viscosity, final viscosity, breakdown value and aging recovery value. The higher the aging recovery value, the less resistant it is to aging. The results are shown in Tables 10 and Figure 10 .

[0192] Table 10 Test Example 2: Aging recovery value (setback)

[0193] Aging recovery value (setback) Example 4 20 Comparative Example 1 180 Comparative Example 2 75 Comparative Example 3 47 Comparative Example 4 62 Comparative Example 5 51

[0194] From the data in Table 10, it can be seen that the starch prepared by the technical solution of the present invention (Example 4) has good anti-aging performance. After the original cassava starch (Comparative Example 1) is modified and enzymatically hydrolyzed and a dry powder of a mixture of chitosan and sodium alginate is added, the anti-aging performance is improved several times.

[0195] From the above embodiments, comparative examples and test examples, it can be seen that the present invention discloses a preparation process and application of a lipophilic composite modified starch, which uses cassava starch as raw material, undergoes mechanical activation, and then undergoes phosphorylation and cross-linking denaturation to obtain phosphate-modified starch, which is then subjected to a three-enzyme synergistic hydrolysis denaturation, and the degree of denaturation is controlled by controlling the enzymatic hydrolysis concentration and enzymatic hydrolysis time. First, the starch branching enzyme part catalyzes the conversion of amylose into amylopectin, and then the β-amylase part is used to continuously cut off maltose from the non-reducing end of the starch, thereby reducing the length of the starch outer chain and producing β-glucan. Finally, Pullulanase is used to further cut the α-1,6 glycosidic bonds of β-glucan to form linear chains of appropriate length. The final modified starch produced has the dual properties of cross-linked starch and esterified starch. It has good amphiphilic properties, high viscosity, and resistance to dehydration (aging), making it more practical. Especially after further mixing with chitosan and sodium alginate, its lipophilic properties at low temperatures are further enhanced, and it has good freeze-thaw resistance, making it very suitable for use in the food processing industry, especially in the field of low-temperature meat processing and transportation.

[0196] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. Application of a lipophilic composite modified starch in low-temperature meat processing and transportation, characterized in that: The lipophilic composite modified starch is prepared by the following steps: 1) Using cassava starch as raw material, after mechanical activation, it is subjected to phosphorylation, cross-linking and denaturation to obtain phosphoric acid modified starch; 2) pre-treating the phosphoric acid-modified starch to obtain a pre-treated solution, and subjecting the pre-treated solution to continuous three-enzyme modification and denaturation to obtain the lipophilic composite modified starch; The pretreatment described in step 2) comprises the following steps: a. Add water to the phosphoric acid modified starch to prepare starch emulsion with a liquid-to-solid ratio of 3:1-4:1, then heat to 45-55°C and stir for 10-20 minutes; b. High-pressure homogenization of the starch emulsion at 300-500 bar for 1-5 minutes; c. Slowly add the vegetable oil with a final mass fraction of 3%-6% into the homogenized starch solution and stir evenly; d. Perform low-frequency ultrasound on the starch solution using an intermittent ultrasonic device at 20 kHz for 30-60 seconds each time, repeating 3-6 times to obtain a pretreated solution; The three-enzyme continuous modification and denaturation in step 2) comprises the following steps: 21) Modification and denaturation of starch branching enzyme: The pH value of the pretreatment solution is adjusted to 7.0-8.0, and the temperature is maintained at 47-53° C., and then starch branching enzyme is added for preliminary directional enzymatic hydrolysis for 1-2 hours. The enzyme is inactivated to obtain a primary enzymatic hydrolyzate. The amount of starch branching enzyme added is 100-200 U / mL of pretreatment solution; 22) Modification and denaturation of β-amylase: The pH of the primary enzymatic hydrolysate was adjusted to 5.0-7.0 and the temperature was maintained at 55-60°C. β-amylase was then added for secondary enzymatic hydrolysis for 2-3 hours, and the enzyme was inactivated to obtain a secondary enzymatic hydrolysate. The β-amylase was added at a concentration of 150-300 U / mL of the primary enzymatic hydrolysate. 23) Pullulanase modification and denaturation: The pH of the secondary enzymatic hydrolysate was adjusted to 4.0-6.0 and the temperature was 60-65° C., and then pullulanase was added to perform tertiary enzymatic hydrolysis for 2-3 hours, and the enzyme was inactivated to obtain a tertiary enzymatic hydrolysate; the pullulanase was added in an amount of 100-200 U / mL of the secondary enzymatic hydrolysate; The mechanical activation in step 1) comprises the following steps: placing the cassava starch in an oven for drying, taking it out when the moisture content is less than 5%, and placing it in a planetary ball mill for ball milling at a ball-to-material ratio of 2-4:1, rotating at 400-600 rpm, and grinding for 30-120 minutes; and immediately performing phosphorylation and cross-linking denaturation after taking it out; In the step 1), a sodium trimetaphosphate aqueous solution containing 4% to 10% sodium trimetaphosphate is selected, and mechanically activated cassava starch is added to the sodium trimetaphosphate solution at a liquid-to-solid ratio of 1:1 to 4:

1. The mixture is stirred and mixed, and the pH is adjusted to 10 to 12 using sodium hydroxide. The stirring is continued for 60 to 120 minutes, and the temperature is controlled at 42 to 60° C. to obtain a phosphorylated cross-linked modified starch suspension. The suspension is placed in a centrifuge and centrifuged at 3000 g for 10 to 20 minutes. The precipitate is collected, dried, and passed through a 100-200 mesh sieve; The method further includes step 3) post-processing, comprising the following steps: adding a dry powder of a mixture of chitosan and sodium alginate at a final mass fraction of 2-5% to the third-stage enzymatic hydrolysate, stirring the mixture evenly, centrifuging the solution, washing the precipitate to neutrality, filtering the precipitate, and vacuum drying the precipitate to obtain a lipophilic composite modified starch; The mass ratio of the chitosan to sodium alginate is 2:1-1:1.

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