A method for preparing a cassava whole cell flour special diet ingredient

Abstract

The application discloses a preparation method of cassava whole cell powder special-diet ingredient, and belongs to the field of special-diet food development. The application provides a kind of anti-digestion cassava whole cell powder special-diet food ingredient, which utilizes pectinase to enzymatically hydrolyze and separate cassava tuber tissues, to prepare single complete cassava cells, and utilizes the non-covalent force between cell wall polysaccharides and phenolic substances to promote the cell wall to adsorb phenolic active substances, to enhance the strength of the cell wall and the inhibitory effect on digestive enzymes, and at the same time, the cassava whole cell powder is treated by wet heat, to promote the rearrangement of intracellular starch molecular chains of the cassava whole cell, to further enhance the anti-digestion capacity of the starch.

Description

Technical Field

[0001] This invention relates to a method for preparing a special dietary ingredient from cassava whole cell powder, belonging to the field of special dietary food development. Background Technology

[0002] Type I resistant starch (RS1), also known as physically encapsulated starch, mainly includes starch granules encapsulated in grains, seeds, or tubers by cell walls or proteins. The production of resistant starch primarily involves three mechanisms: First, the entanglement of cell wall polysaccharides forms a physical barrier, and the lack of cell wall-degrading enzymes in the gastrointestinal tract hinders the hydrolysis of intracellular starch by digestive enzymes. Second, the tight encapsulation of starch within the cell wall, along with the dense cytoplasm and surface proteins of the starch granules, reduces the binding of digestive enzymes to starch. Third, cell wall components such as cellulose, hemicellulose, and pectin can specifically bind to amylases, inhibiting their activity.

[0003] Cassava, one of the world's three major tuber crops and known as the "King of Starch," is a staple food for 800 million people worldwide. Currently, my country has cultivated various edible cassava products, which, in addition to starch, are rich in cellulose, protein, and minerals, serving as an important supplement to grains. Cassava, like other legumes, is a dicotyledonous plant. Its starch is encased in cell walls and held together by a pectin-rich interlayer. Compared to monocotyledons like corn, rice, and wheat, it has thicker cell walls, which inhibit the hydrolysis of intracellular starch by digestive enzymes. Cassava starch is easily digestible and has a high digestibility, classifying it as a medium-to-high GI food. Therefore, resistant starch can be prepared by isolating natural cells to reduce its digestibility. Previous reports have indicated that isolating legume cells through acid-base or heat treatment can increase the content of resistant starch. However, prolonged acid-base separation and increased cell wall permeability during heat treatment lead to a decrease in the content of resistant starch.

[0004] Therefore, providing an efficient whole-cell separation method for cassava while further enhancing the intracellular resistant starch content is of great significance for developing cassava-based dietary ingredients and realizing the high-value application of cassava resources. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a special dietary ingredient: cassava whole-cell powder with anti-digestive properties. It utilizes pectinase to enzymatically hydrolyze and separate cassava tuber tissue, preparing individual, intact cassava cells. Furthermore, it leverages the non-covalent interactions between cell wall polysaccharides and phenolic substances to promote the adsorption of phenolic active substances into the cell wall, thereby enhancing cell wall strength and its inhibitory effect on digestive enzymes. Simultaneously, it employs moist heat treatment of the cassava whole-cell powder to induce rearrangement of intracellular starch molecular chains, further enhancing the starch's resistance to digestion.

[0006] The first objective of this invention is to provide a fortified cassava whole-cell powder, the preparation method of which includes:

[0007] (1) Whole cell isolation of cassava: Cassava blocks were enzymatically hydrolyzed using pectinase hydrolysate. The ratio of cassava blocks to pectinase hydrolysate was 1:8-10, and cassava samples after enzymatic hydrolysis were obtained.

[0008] (2) Whole cell sieving: After enzymatic hydrolysis and separation, cassava samples were sieved and whole cell powder with a particle size of 50-250 μm was collected.

[0009] (3) Resuspend the cassava whole cell powder to obtain a whole cell suspension. Mix the whole cell suspension with a polyphenol solution and react to prepare cassava whole cells adsorbed with polyphenols.

[0010] (4) The cassava whole cells adsorbed with polyphenols were subjected to wet heat treatment, dried and prepared to obtain reinforced cassava whole cell powder; the wet heat treatment was as follows: the moisture content of the cassava whole cells adsorbed with polyphenols was adjusted to 15-35% w / w and treated at 90-110℃ for 1-5 h.

[0011] Unless otherwise specified, the unit for the feed-liquid ratio in this application is kg:L; the unit for w / v is kg / L.

[0012] In one embodiment, the pectinase hydrolysate in step (1) is prepared by dissolving pectinase in citrate buffer to a final concentration of 0.5–5 U / mL; adding 3–5% w / v ascorbic acid and activating at 45–50°C for 0.5–1 h to obtain the pectinase hydrolysate; the hydrolysis conditions are 45–50°C for 1–2 h.

[0013] In one embodiment, the citrate buffer solution has a concentration of 0.1 M and a pH of 3.5.

[0014] In one embodiment, the enzymatic hydrolysis reaction is accompanied by stirring at a speed of 80–100 r / min.

[0015] In one embodiment, the sieving in step (2) involves using two layers of sieves to sieve the cells. The first layer of sieve has a mesh size of 200-250 μm, and the second layer of sieve has a mesh size of 50-75 μm. The cassava sample on the second layer of sieve is collected to obtain whole cassava cell powder.

[0016] In one embodiment, the cassava sample after enzymatic hydrolysis and separation is rinsed with running water 5 to 8 times.

[0017] In one embodiment, the preparation method of the polyphenol-ethanol solution in step (3) includes: dissolving the polyphenolic substance in ethanol with a volume fraction of 75-85% to obtain a polyphenol-ethanol solution, wherein the concentration of the polyphenolic substance is 30-40% w / v.

[0018] In one embodiment, the polyphenols in step (3) include one or more of anthocyanins, gallic acid, catechins, chlorogenic acid, ferulic acid, and epicatechin.

[0019] In one embodiment, the concentration of cassava whole cell powder in the whole cell suspension in step (3) is 20-30% w / v; the volume ratio of the whole cell suspension to the polyphenol solution is 10:1-2.

[0020] In one embodiment, in step (3), unbound free polyphenols in cassava whole cells are removed by centrifugation at 5000 rpm for 10-15 min.

[0021] In one embodiment, the moisture content of the fortified cassava whole cell powder in step (4) is ≤14%.

[0022] In one embodiment, in step (4), the moisture content of the whole cassava cells is 20% after wet heat treatment, the wet heat treatment temperature is 90°C, and the treatment time is 3 hours.

[0023] In one embodiment, the drying temperature in step (4) is 40℃~60℃ and the drying time is 12~24h.

[0024] A second objective of this invention is to provide the application of any of the above-mentioned fortified cassava whole cell powder in the preparation of products, characterized in that the products are: food, additives, pharmaceuticals, or health products;

[0025] Optionally, the food is a starch-based food, including but not limited to starch, bread, noodles, steamed buns, dumplings, biscuits, and cakes; optionally, the additives include but are not limited to thickeners, emulsifiers, stabilizers, or preservatives; optionally, the medicine includes but is not limited to fillers, binders, disintegrants, flow aids, or drug carriers; optionally, the health products include but are not limited to resistant starch, pregelatinized starch, slow-digesting starch, and modified starch.

[0026] A third objective of this invention is to provide a product containing any of the aforementioned fortified cassava whole-cell powders; the product is: food, additive, pharmaceutical, or health product;

[0027] Optionally, the food is a starch-based food, including but not limited to starch, bread, noodles, steamed buns, dumplings, biscuits, and cakes; optionally, the additives include but are not limited to thickeners, emulsifiers, stabilizers, or preservatives; optionally, the medicine includes but is not limited to fillers, binders, disintegrants, flow aids, or drug carriers; optionally, the health products include but are not limited to resistant starch, pregelatinized starch, slow-digesting starch, and modified starch.

[0028] The fourth objective of this invention is to provide a method for increasing the resistant starch content in cassava flour products, specifically for preparing whole-cell cassava flour. The method for preparing the whole-cell cassava flour includes:

[0029] (1) Whole cell isolation of cassava: Cassava blocks were enzymatically hydrolyzed using pectinase hydrolysate. The ratio of cassava blocks to pectinase hydrolysate was 1:8-10, and cassava samples after enzymatic hydrolysis were obtained.

[0030] (2) Whole cell sieving: After enzymatic hydrolysis and separation, cassava samples were sieved and whole cell powder with a particle size of 50-250 μm was collected.

[0031] (3) Resuspend the cassava whole cell powder to obtain a whole cell suspension. Mix the whole cell suspension with a polyphenol solution and react to prepare cassava whole cells adsorbed with polyphenols.

[0032] (4) The cassava whole cells adsorbed with polyphenols were subjected to wet heat treatment, dried and prepared to obtain reinforced cassava whole cell powder; the wet heat treatment was as follows: the moisture content of the cassava whole cells adsorbed with polyphenols was adjusted to 20-30%, and treated at 90-110℃ for 1-5 hours.

[0033] In one embodiment, the pectinase hydrolysate in step (1) is prepared by dissolving pectinase in citrate buffer to a final concentration of 0.5–5 U / mL; adding 3–5% w / v ascorbic acid and activating at 45–50°C for 0.5–1 h to obtain the pectinase hydrolysate; the hydrolysis conditions are 45–50°C for 1–2 h.

[0034] In one embodiment, the sieving in step (2) involves using two layers of sieves to sieve the cells. The first layer of sieve has a mesh size of 200-250 μm, and the second layer of sieve has a mesh size of 50-75 μm. The cassava sample on the second layer of sieve is collected to obtain whole cassava cell powder.

[0035] In one embodiment, the preparation method of the polyphenol solution in step (3) includes: dissolving polyphenols in ethanol with a volume fraction of 75-85% to obtain a polyphenol-ethanol solution, wherein the concentration of polyphenols is 30-40% w / v.

[0036] In one embodiment, the polyphenols in step (3) include one or more of anthocyanins, gallic acid, catechins, chlorogenic acid, ferulic acid, and epicatechin.

[0037] In one embodiment, the concentration of cassava whole cell powder in the whole cell suspension in step (3) is 20-30% w / v; the volume ratio of the whole cell suspension to the polyphenol solution is 10:1-2.

[0038] The beneficial effects of this invention are:

[0039] This invention provides a special dietary ingredient: cassava whole-cell powder with anti-digestive properties. It utilizes pectinase to enzymatically hydrolyze and separate cassava tuber tissue, preparing individual, intact cassava cells. Furthermore, it leverages the non-covalent interaction between cell wall polysaccharides and phenolic substances to promote the adsorption of phenolic active substances into the cell wall, thereby enhancing cell wall strength and its inhibitory effect on digestive enzymes. Simultaneously, it employs moist heat treatment of the cassava whole-cell powder to promote the rearrangement of intracellular starch molecular chains, further enhancing the starch's resistance to digestion.

[0040] Specifically:

[0041] (1) The present invention uses enzymatic separation of cassava whole cells. Compared with acid-base separation and hydrothermal separation technology, the separation time is short, the efficiency is high, and it does not affect the intracellular starch structure. Moreover, the separated individual cassava cells have the characteristics of strong uniformity, good dispersibility and strong palatability compared with the unseparated cell cluster particles.

[0042] (2) The resistant cassava whole cell powder prepared by the present invention is made by combining enzymatic method, physical adsorption and wet heat treatment. Compared with chemically modified resistant starch, it is natural, safe and non-toxic, and has significant environmental advantages.

[0043] (3) In this invention, the interaction between cell wall polysaccharides and phenolic substances is utilized to enhance the shear resistance; at the same time, phenolic substances have the effect of inhibiting digestive enzymes, which can further enhance the physical barrier effect of the cell wall on amylase, increase the content of resistant starch, and the resistant starch content in the raw sample of cassava whole cell powder prepared reaches more than 72.7%, with a maximum of 78.7%; the resistant starch content in the cooked sample reaches more than 30.2%, with a maximum of 35.8%.

[0044] (4) The present invention regulates the intracellular starch molecular structure by moist heat treatment. Because moist heat treatment causes the starch molecular chain to rearrange to produce a resistant molecular structure, the intracellular starch has enhanced its resistance to digestion.

[0045] (5) The technical process of this invention is simple, the production efficiency is high, the cost is low, and it is easy to achieve large-scale production. At the same time, it provides a new idea for the high-value processing of cassava resources. Attached Figure Description

[0046] Figure 1Microscopic structures of cassava whole-cells isolated using different methods;

[0047] Figure 2 To enhance the shear resistance of cassava whole cells and strengthen the shear resistance of cassava whole cells. Detailed Implementation

[0048] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0049] Test method:

[0050] 1. Microscopic observation of cassava samples

[0051] The whole-cell structure of cassava was observed under normal light using an optical microscope, and the cell wall integrity was observed by staining the cells with 0.1% Congo red.

[0052] 2. Determination of shear resistance of cassava whole cells and enhanced whole cells

[0053] Add 2g of dried cell sample to 20mL of distilled water, gelatinize in a boiling water bath for 10min, and after cooling, measure the shear resistance of the sample using a rheometer. The test procedure is as follows: within 3min, the rotation speed is increased from 0rad / s to 150rad / s, and then decreased from 150rad / s to 0rad / s at the same rate to form a thixotropic ring. The size of the thixotropic ring represents the shear resistance of the sample and can reflect the strength of the cell wall. The smaller the thixotropic ring area, the less energy is required to return to the original state, that is, the stronger the shear resistance and the greater the cell wall strength.

[0054] 3. Determination of resistant starch content in cooked and uncooked samples

[0055] Uncooked sample: Take 200mg of sample and place it in a 50mL centrifuge tube, add 2mL of water, mix well and place in a 37℃ constant temperature water bath and shake (speed is 160rpm);

[0056] Sample cooking: Take 200 mg of sample and place it in a 50 mL centrifuge tube, add 2 mL of water, mix well and then place it in a boiling water bath for 10 min.

[0057] Add 4 mL of pepsin solution (containing 0.5 g pepsin dispersed in 100 mL of 5 mol / L hydrochloric acid solution) to the above reaction system and react for 30 min. Then add 2 mL of 0.5 mol / L sodium acetate solution (pH = 5.2) to each test centrifuge tube and continue shaking for 30 min. Next, add 0.2 mL of mixed enzyme solution (8 g pancreatin and 1.96 mL of glucoamylase (260 U / mL) dispersed in 44.8 mL of water), hydrolyze for 120 min, take 0.1 mL of sample and add 0.9 mL of 90% ethanol to inactivate the enzyme. After centrifugation at 10000 rpm for 5 min, take the supernatant and determine the glucose content using a glucose oxidase kit (GOD-POD).

[0058] Resistant starch (RS) is starch that is not digested and absorbed by the small intestine within 120 minutes. The specific formula is as follows:

[0059]

[0060] Where: G 120 The glucose released after 120 min of enzymatic hydrolysis is in mg / mL, and TS is the total dry weight of starch in the sample in mg / mL.

[0061] Raw materials used in the examples:

[0062] Cassava was purchased from Guangxi Kangyi Ecological Agriculture Development Co., Ltd.

[0063] Example 1: Preparation method of fortified cassava whole cell powder

[0064] The steps for preparing cassava whole-cell powder are as follows:

[0065] (1) Peel and cut cassava into chunks: Peel and wash fresh cassava, cut it into chunks (3mm×3mm), and soak it in water;

[0066] (2) Whole-cell isolation of cassava: Pectinase was dissolved in citrate buffer (0.1M pH=3.5) to prepare 2U / mL enzymatic hydrolysate, and 5% w / v ascorbic acid was added. The hydrolysate was activated at 50℃ for 0.5h to obtain preheated and activated enzymatic hydrolysate. Cassava pieces were added to the preheated and activated enzymatic hydrolysate at a material-to-liquid ratio of 1:10. The mixture was stirred continuously at 50℃ (100rpm) for 2h to obtain enzymatically isolated cassava samples.

[0067] (3) Whole cell sieving: The cassava sample prepared in step (2) after enzymatic hydrolysis and separation is rinsed with running water and the cells are sieved through a double-layer sieve. The first layer of sieve has a pore size of 250 μm and the second layer of sieve has a pore size of 75 μm. The whole cassava cells separated on the second layer of sieve are collected.

[0068] (4) Cell wall adsorption of polyphenols: The cassava whole cells obtained in step (3) were suspended in 0.05M citrate buffer solution with pH=5 to prepare a 30% w / v cassava whole cell suspension. Quercetin was dissolved in 80% ethanol to prepare a 30% quercetin-ethanol solution. The cassava whole cell suspension and the quercetin-ethanol solution were mixed at a volume ratio of 10:1. The mixture was stirred at 35℃ (100 rpm) for 5 h. The unbound free polyphenols were removed by centrifugation and dehydration to obtain cassava whole cells adsorbed with polyphenols.

[0069] (5) Moist heat treatment: The cassava whole cells with adsorbed polyphenols prepared in step (4) were placed in an oven at 50°C to adjust the moisture content to 20% and then treated at 110°C for 2 hours.

[0070] (6) Cooling and drying: The product obtained in step (4) is dried in an oven at 50°C for 24 hours until the moisture content is ≤14% to prepare fortified cassava whole cell powder.

[0071] Example 2: Preparation method of fortified cassava whole cell powder

[0072] Based on Example 1, quercetin was replaced with anthocyanins, and the remaining steps were the same as in Example 1 to prepare fortified cassava whole cell powder.

[0073] Example 3: Preparation method of fortified cassava whole cell powder

[0074] Based on Example 1, the conditions for cassava whole cell separation in step (2) were changed as follows: pectinase was dissolved in citrate buffer (0.1M pH=3.5) to prepare a 5U / mL enzymatic hydrolysate, and 3% w / v ascorbic acid was added. The hydrolysate was activated at 45℃ for 1h to obtain a preheated and activated enzymatic hydrolysate. Cassava pieces were added to the preheated and activated enzymatic hydrolysate at a material-to-liquid ratio of 1:8. The mixture was stirred continuously at 50℃ (100rpm) for 3h. The remaining steps were the same as in Example 1 to obtain fortified cassava whole cell powder.

[0075] Example 4: Preparation method of fortified cassava whole cell powder

[0076] Based on Example 1, the cell wall adsorption of polyphenols in step (4) was changed as follows: the cassava whole cells obtained in step (3) were suspended in 0.05M, pH=5 citrate buffer solution to prepare a 35% w / v cassava whole cell suspension. Quercetin was dissolved in 80% ethanol to prepare a 20% quercetin-ethanol solution. The cassava whole cell suspension and the quercetin-ethanol solution were mixed at a volume ratio of 10:1. The mixture was stirred at 35°C (100 rpm) for 3 hours. The remaining steps were the same as in Example 1 to prepare the enhanced cassava whole cell powder.

[0077] Example 5: Preparation method of fortified cassava whole cell powder

[0078] Based on Example 1, the wet heat treatment in step (5) was changed as follows: the cassava whole cells with adsorbed polyphenols prepared in step (4) were placed in an oven at 50°C to adjust the moisture content to 30%, and then treated at 110°C for 1 hour. The remaining steps were the same as in Example 1, and the enhanced cassava whole cell powder was prepared.

[0079] Example 6: Preparation method of fortified cassava whole cell powder

[0080] Based on Example 1, the conditions for cell wall adsorption of polyphenols in step (4) were changed, while the remaining steps were the same as in Example 1, and cassava whole cell powder was prepared. The specific conditions are shown in Table 1.

[0081] Table 1 Polyphenol Adsorption Conditions

[0082] Polyphenol concentration Cell suspension concentration reaction time Combination 1 40％ 20％ 1h Combination 2 35％ 35％ 2h

[0083] Comparative Example 1: Preparation of Cassava Starch

[0084] Fresh cassava was peeled and cut into chunks, and twice the amount of distilled water was added. The mixture was then crushed in a high-speed blender for 15 minutes. The cassava starch was then sieved through a 300-mesh screen. The filtrate was collected, vacuum filtered to remove water, washed with ethanol, centrifuged to remove water, and dried in an oven at 50°C for 24 hours. The cassava starch was collected and its RS (resistant starch) content was analyzed.

[0085] Comparative Example 2: Preparation of Cassava Flour

[0086] Fresh cassava was peeled and sliced, dried in an oven at 60℃ for 24 hours, then pulverized using a grinder and passed through an 80-mesh sieve to obtain cassava flour. Its RS (resistant starch) content was analyzed.

[0087] Comparative Example 3: Cassava Starch Treated with Moist Heat

[0088] The cassava starch prepared in Comparative Example 1 was adjusted to a moisture content of 20% in an oven at 50℃ and then treated at 110℃ for 2 hours to obtain wet-heat treated cassava starch.

[0089] Comparative Example 4: Cassava Whole Cell Powder without Polyphenol Enhancement

[0090] Based on Example 1, step (4) is omitted, and the remaining steps are the same as in Example 1, to prepare cassava whole cell powder.

[0091] Comparative Example 5: No damp heat treatment used

[0092] Based on Example 1, step (5) is omitted, and the remaining steps are the same as in Example 1, to prepare cassava whole cell powder.

[0093] Comparative Example 6: No polyphenol enhancement and hydrothermal treatment used

[0094] Based on Example 1, steps (4) and (5) are omitted, and the remaining steps are the same as in Example 1, to prepare cassava whole cell powder.

[0095] Comparative Example 7: Further digestion using cellulase

[0096] Based on Example 1, the whole cell sieving in step (3) was changed as follows: the cassava sample obtained after enzymatic hydrolysis and separation in step (2) was placed in a cellulase solution (10 U / mL) and stirred continuously at 50°C for 2 hours to obtain cassava cells with broken cell walls; the broken cassava cells were then rinsed with running water and sieved through a double-layer sieve, wherein the first sieve has a pore size of 250 μm and the second sieve has a pore size of 75 μm, and the remaining steps are the same as in Example 1 to prepare whole cell powder of broken cassava cells.

[0097] Comparative Example 8: Polyphenols and hydrothermally treated cassava starch

[0098] Take the cassava starch prepared in Comparative Example 1 and subject it to polyphenol and wet heat treatment. The steps are the same as steps (2) to (6) in Example 1 to prepare polyphenol and wet heat treated cassava starch.

[0099] Comparative Example 9: Polyphenols, Wet Heat Treated Cassava Flour

[0100] Take the cassava flour prepared in Comparative Example 2 and subject it to polyphenol and wet heat treatment. The steps are the same as steps (2) to (6) in Example 1 to prepare polyphenol and wet heat treated cassava flour.

[0101] Comparative Example 10: Changing the temperature of the damp heat treatment

[0102] Based on Example 1, the wet heat treatment conditions in step (5) were changed, while the remaining steps were the same as in Example 1, and cassava whole cell powder was prepared. The specific conditions are shown in Table 2.

[0103] Table 2. Conditions for damp heat treatment

[0104] Moisture content temperature Processing time Combination 1 25％ 130℃ 1h Combination 2 30％ 70℃ 2h

[0105] Comparative Example 11: Preparation of whole-cell cassava using conventional methods

[0106] The steps for preparing cassava whole cells using traditional methods are as follows:

[0107] 1. Acid-base separation

[0108] Peel the cassava tubers and cut them into 3×3×3mm cubes. Soak 200g of cassava cubes in a 0.05M HCl solution for 6 hours, then soak them in a 0.025M NaOH solution overnight. Crush the acid- and alkali-soaked cassava cubes into a paste, and then pass the paste through 75μm and 250μm sieves under running water. Collect the cassava cells that remain on the 250μm sieve.

[0109] 2. Hydrothermal separation

[0110] Peel the cassava tubers and cut them into small cubes of 5×5×5cm. Place 200g of cassava cubes in 2L of water and incubate at 80℃ for 3 hours. After hydrothermal treatment, crush the cassava cubes into a paste and then pass them through 75μm and 250μm sieves under running water, collecting the cassava cells that remain on the 250μm sieve.

[0111] The prepared cassava whole cells were subjected to polyphenol and moist heat treatment, with the steps being consistent with steps (2) to (6) in Example 1, to prepare fortified cassava whole cell powder.

[0112] Example 7: Detection of resistant starch content

[0113] The resistant starch content of the powders prepared in Examples 1-6 and Comparative Examples 1-11 was tested, and the results are shown in Table 3.

[0114] Table 3 Results of resistant starch content determination

[0115]

[0116]

[0117] The results showed that, compared with starch (Comparative Example 1), the resistant starch content in raw cassava whole cells isolated by pectinase (Comparative Example 6) increased by about 20%, and the resistant starch content in cooked samples increased by 7%. This was mainly due to the swelling pressure generated by starch absorbing water and swelling during cooking, which increased the cell wall pores, enhanced permeability, and weakened the physical barrier effect against digestive enzymes. The resistant starch content in raw cassava whole cell powder prepared in Examples 1-5 reached over 72.7%, with a maximum of 78.7%; the resistant starch content in cooked samples reached over 30.2%, with a maximum of 35.8%.

[0118] Whole-cell micrographs of cassava prepared by different cassava isolation methods are shown below. Figure 1 As shown, the results indicate that the cassava cell wall is damaged after acid-base separation, while hydrothermal separation leads to the destruction of the intracellular starch structure. Enzymatic separation of cassava cells can maintain the integrity of the cell wall and has no significant effect on the intracellular starch structure.

[0119] Figure 2The area of ​​the thixotropic ring represents the shear resistance of the sample; a smaller area indicates greater shear resistance. The results show that cassava cells enhanced by polyphenol adsorption exhibit increased shear resistance, indicating that polyphenol adsorption strengthens the cell wall. After polyphenol adsorption and appropriate humid heat treatment (Example 1), whole cassava cells showed a 10% increase in resistant starch content compared to untreated cells, further enhancing the anti-digestion properties of intracellular starch and mitigating damage to cell permeability caused by heat treatment. Furthermore, synergistic treatment of cassava starch and cassava flour with polyphenols and humid heat significantly increased the resistant starch content in whole cassava cells, demonstrating the important role of the cell wall in delaying intracellular starch hydrolysis.

[0120] The cassava cell powder prepared by this invention has high separation efficiency and multiple nutritional components, as well as high resistance to digestion. It can also maintain a high resistant starch content after heat processing, and can be used as a special dietary food ingredient for the prevention of diabetes, improvement of intestinal health, and weight control.

[0121] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A fortified cassava whole-cell powder, characterized in that, The preparation method of the fortified cassava whole cell powder includes: (1) Whole cell isolation of cassava: Cassava blocks were enzymatically hydrolyzed using pectinase hydrolysate. The ratio of cassava blocks to pectinase hydrolysate was 1:8~10, and cassava samples after enzymatic hydrolysis were prepared. (2) Whole cell sieving: After enzymatic hydrolysis and separation, cassava samples were sieved and whole cell powder with a particle size of 50~250μm was collected. (3) Resuspend the cassava whole cell powder to obtain a whole cell suspension. Mix the whole cell suspension with a polyphenol solution and react to prepare cassava whole cells adsorbed with polyphenols. (4) The cassava whole cells adsorbed with polyphenols were subjected to wet heat treatment, dried and prepared to obtain reinforced cassava whole cell powder; the wet heat treatment was as follows: the moisture content of the cassava whole cells adsorbed with polyphenols was adjusted to 15~35%w / w and treated at 90~110℃ for 1~5 h. The preparation method of pectinase hydrolysate in step (1) is as follows: dissolve pectinase in citrate buffer to make the final concentration of pectinase 0.5~5U / mL; add 3~5% w / v ascorbic acid, activate at 45~50℃ for 0.5~1h to prepare pectinase hydrolysate; the hydrolysis conditions are 45~50℃ for 1~2h. In step (2), the cells are sieved using two layers of sieves. The first layer of sieves has a pore size of 200-250 μm, and the second layer of sieves has a pore size of 50-75 μm. The cassava sample on the second layer of sieves is collected to obtain whole cassava cell powder. The preparation method of polyphenol-ethanol solution in step (3) includes: dissolving polyphenolic substances in 75-85% ethanol by volume to obtain polyphenol-ethanol solution, wherein the concentration of polyphenolic substances is 30-40% w / v; In step (3), polyphenols include one or more of anthocyanins, gallic acid, catechins, chlorogenic acid, ferulic acid, and epicatechin; The concentration of cassava whole cell powder in the whole cell suspension in step (3) is 20-30% w / v; the volume ratio of whole cell suspension to polyphenol solution is 10:1-2.

2. The application of the fortified cassava whole-cell powder according to claim 1 in the preparation of products, characterized in that, The products mentioned are: food, additives, or pharmaceuticals.

3. The application according to claim 2, characterized in that, The food is a starch-based food, including starch, bread, noodles, steamed buns, dumplings, biscuits, or cakes; the additives include thickeners, emulsifiers, stabilizers, or preservatives.

4. The application according to claim 2, characterized in that, The drug includes fillers, binders, disintegrants, flow aids, or drug carriers.

5. A product characterized in that, The product contains the fortified cassava whole cell powder as described in claim 1; the product is: food, additive, or pharmaceutical.

6. The product according to claim 5, characterized in that, The food is a starch-based food, including starch, bread, noodles, steamed buns, dumplings, biscuits, or cakes; the additives include thickeners, emulsifiers, stabilizers, or preservatives.

7. The product according to claim 5, characterized in that, The drug includes fillers, binders, disintegrants, flow aids, or drug carriers.

8. A method for increasing the resistant starch content in cassava flour products, characterized in that, The method for preparing cassava whole-cell powder includes: (1) Whole cell isolation of cassava: Cassava blocks were enzymatically hydrolyzed using pectinase hydrolysate. The ratio of cassava blocks to pectinase hydrolysate was 1:8~10, and cassava samples after enzymatic hydrolysis were prepared. (2) Whole cell sieving: After enzymatic hydrolysis and separation, cassava samples were sieved and whole cell powder with a particle size of 50~250μm was collected. (3) Resuspend the cassava whole cell powder to obtain a whole cell suspension. Mix the whole cell suspension with a polyphenol solution and react to prepare cassava whole cells adsorbed with polyphenols. (4) The cassava whole cells adsorbed with polyphenols were subjected to wet heat treatment and dried to prepare reinforced cassava whole cell powder; the wet heat treatment was as follows: the moisture content of the cassava whole cells adsorbed with polyphenols was adjusted to 20-30%, and treated at 90-110℃ for 1-5 h. The preparation method of pectinase hydrolysate in step (1) is as follows: dissolve pectinase in citrate buffer to a final concentration of 0.5-5 U / mL; add 3-5% w / v ascorbic acid and activate at 45-50℃ for 0.5-1h to prepare pectinase hydrolysate; the hydrolysis conditions are 45-50℃ for 1-2h. In step (2), the cells are sieved using two layers of sieves. The first layer of sieves has a pore size of 200-250 μm, and the second layer of sieves has a pore size of 50-75 μm. The cassava sample on the second layer of sieves is collected to obtain whole cassava cell powder. The preparation method of polyphenol solution in step (3) includes: dissolving polyphenol in 75-85% ethanol by volume to obtain polyphenol-ethanol solution, wherein the concentration of polyphenol is 30-40% w / v; In step (3), polyphenols include one or more of anthocyanins, gallic acid, catechins, chlorogenic acid, ferulic acid, and epicatechin; The concentration of cassava whole cell powder in the whole cell suspension in step (3) is 20-30% w / v; the volume ratio of whole cell suspension to polyphenol solution is 10:1-2.

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