A cassava whole cell powder preparation and method for its use as a staple food replacement

Abstract

The application discloses a cassava whole cell powder preparation and main food replacement method, and belongs to the field of special diet food development. 2+ The intermediate thin layer adhered between cell clusters is decomposed by pectinase to prepare single and complete cassava cells, and Ca The solution is used for impregnating cells to improve the binding capacity between cell wall polysaccharide components, strengthen the cell wall, and then the cell wall is used as a main raw material to be compounded with rice protein powder and crushed rice powder, so that a cassava whole cell powder recombined rice is prepared by extrusion technology.

Description

Technical Field

[0001] This invention relates to a method for preparing cassava whole-cell powder and its staple food substitution, belonging to the field of special dietary food development. Background Technology

[0002] Cassava, a plant belonging to the genus *Cassava* in the family Euphorbiaceae, is one of the world's three major tuber crops and is known as the "King of Starch" and "Underground Granary." Cassava is an important food and economic crop, widely cultivated as a staple food in Asia, Africa, and Latin America due to its drought and poor soil tolerance. In my country, however, cassava is defined as a non-food energy crop, mainly grown in Guangxi, Guangdong, Hainan, and Yunnan. With the continuous reduction of arable land, increasing water scarcity, and abnormal climate conditions, utilizing non-traditional food crops like cassava can diversify consumer demand for traditional staple foods, potentially altering the food supply and demand situation and holding significant strategic importance for addressing food security issues.

[0003] Whole cells are the smallest unit of plant tissue. Cassava tuber tissue is composed of multiple parenchyma cells, which are held together by a pectin-rich intercellular layer. A large amount of nutrients (starch, protein, lipids, and trace elements) are surrounded by the cell wall. The cell wall is composed of a rigid, rod-shaped cellulose network and a sticky pectin cross-linking network. Based on this characteristic, the cell wall acts as a natural physical barrier to prevent the loss of nutrients during processing. It also resists the action of digestive enzymes on intracellular starch in the gastrointestinal tract, thereby reducing the postprandial glycemic response. Furthermore, the natural dietary fiber in the cell wall can regulate the intestinal flora, playing a beneficial role in human health.

[0004] Cassava starch has high viscosity and is prone to binding, resulting in high energy consumption during processing, poor product stability, and a relatively high glycemic index. Therefore, from the perspective of taste quality and nutritional health, a special dietary recombinant rice with slow glycemic index and high taste quality is being developed using nutrient-rich cassava whole cell powder as raw material. This rice can be used as a meal replacement food or a sustained energy source for people who are trying to lose weight or have abnormal glucose metabolism. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for preparing cassava whole-cell powder, fortified cassava whole-cell powder, and recombinant rice. This invention utilizes pectinase to enzymatically hydrolyze the thin intermediate layer binding between cells to prepare single, intact cassava whole cells, while simultaneously using Ca... 2+ Solution impregnation of cells enhances the binding capacity between polysaccharide components in the cell wall, strengthening the cell wall. Using these cells as the main raw material, a recombinant rice made from whole cassava cells is prepared via extrusion technology. The method of this invention yields intact whole cassava cells with high separation efficiency. The resulting recombinant rice effectively improves the high viscosity characteristics of cassava starch and exhibits high resistance to digestion.

[0006] The first objective of this invention is to provide a 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 (kg:L) was 1:8-10, and cassava samples after enzymatic hydrolysis were prepared.

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

[0010] In one embodiment, the cassava chunks are prepared by peeling and washing cassava, cutting it into chunks (3mm×3mm), and soaking it in a liquid-to-material ratio of 1:(5~7) for 20~24h.

[0011] In one embodiment, the enzymatic hydrolysis conditions in step (1) are 45-50°C for 1-2 hours; alternatively, the enzymatic hydrolysis is carried out under stirring conditions of 80-100 r / min and reaction at 50°C for 1.5 hours.

[0012] In one embodiment, the preparation method of the pectinase hydrolysate in step (1) is as follows:

[0013] 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°C for 0.5–1 h to prepare pectinase hydrolysate; optionally, activate at 50°C for 0.5 h.

[0014] In one embodiment, the citrate buffer solution has a concentration of 0.1 M and a pH of 3.5.

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

[0016] The second objective of this invention is to provide a fortified cassava whole cell powder, wherein the preparation method of the fortified cassava whole cell powder includes: soaking any of the above-mentioned cassava whole cell powders in a calcium ion solution for 15 to 40 minutes; wherein the concentration of the cassava whole cell powder is 10 to 15% w / v.

[0017] In one embodiment, the calcium ion solution may be one of calcium chloride solution, calcium citrate, calcium phosphate, calcium carbonate, and calcium gluconate. 2+The concentration is 2% to 5%; optionally, after soaking, the fortified cassava whole cell powder is prepared by centrifugation, wherein the centrifugation speed for dehydration is 5000 rpm and the centrifugation time is 10 to 15 min.

[0018] A third objective of this invention is to provide a recombinant rice, the preparation method of which includes:

[0019] (1) Cassava whole cell powder, rice protein powder, and broken rice powder are mixed evenly at a mass ratio (dry basis) of 5-7:0.5-1:3-5 to obtain a powder mixture. Water is added to make the moisture content of the powder mixture reach 30%-40% w / w. After mixing evenly, the mixture is fed into a twin-screw extruder to prepare the extruded product. The moisture content is 30%-40% w / w of the total dry matter of the extruded material.

[0020] (2) The extrusion product obtained in step (1) is dried to prepare cassava whole cell powder recombinant rice, wherein the moisture content of the cassava whole cell powder recombinant rice is ≤10%;

[0021] The cassava whole cell powder is any of the above-mentioned cassava whole cell powders or the above-mentioned fortified cassava whole cell powders.

[0022] In one embodiment, the parameters of the twin-screw extruder in step (1) are set as follows: the feeding speed is 3-5 kg / h, the screw rotation speed is 80-120 r / min, the die diameter is 5-7 mm, and the cutting blade rotation speed is 100-200 r / min; the four temperature ranges of the twin-screw extruder are 45-50℃, 55-60℃, 60-65℃, and 70-75℃, respectively.

[0023] In one embodiment, the mass ratio of cassava whole cell powder, rice protein powder, and rice flour is 7:1:3 (sample calculated by dry weight), the feeding speed is 5 kg / h, the screw speed is 100 r / min, the die orifice diameter is 4 mm, the cutting blade speed is 250 r / min, and the four temperature sections of the twin-screw extruder are 45℃, 50℃, 60℃, and 70℃, respectively.

[0024] In one embodiment, the drying conditions are 90–100°C for 10–15 minutes.

[0025] A fourth object of the present invention is to provide the application of any of the above-mentioned whole cassava cell powders or the above-mentioned fortified whole cassava cell powders or any of the above-mentioned recombinant rice in the preparation of products, said products being: additives, food, pharmaceuticals or health products.

[0026] In one embodiment, the food is a starchy food, including but not limited to starch, bread, noodles, steamed buns, dumplings, biscuits, and cakes.

[0027] In one embodiment, the additives include, but are not limited to, thickeners, emulsifiers, stabilizers, or preservatives.

[0028] In one embodiment, the drug includes, but is not limited to, fillers, binders, disintegrants, flow aids, or drug carriers.

[0029] In one embodiment, the health product includes, but is not limited to, resistant starch, pregelatinized starch, slow-digesting starch, and modified starch.

[0030] A fifth object of the present invention is to provide a product containing one or more of the above-mentioned whole cassava powder, fortified whole cassava powder, or recombinant rice; the product is: food, medicine, or health product.

[0031] In one embodiment, the food is a starchy food, including but not limited to starch, bread, noodles, steamed buns, dumplings, biscuits, and cakes.

[0032] In one embodiment, the additives include, but are not limited to, thickeners, emulsifiers, stabilizers, or preservatives.

[0033] In one embodiment, the drug includes, but is not limited to, fillers, binders, disintegrants, flow aids, or drug carriers.

[0034] In one embodiment, the health product includes, but is not limited to, resistant starch, pregelatinized starch, slow-digesting starch, and modified starch.

[0035] The sixth objective of this invention is to provide a method for reducing the viscosity of cassava flour products by preparing whole-cell cassava flour. The method for preparing the whole-cell cassava flour includes:

[0036] (1) Whole-cell isolation of cassava: Cassava blocks were enzymatically hydrolyzed using pectinase hydrolysate at a ratio of 1:8–10 to obtain enzymatically hydrolyzed cassava samples; among which,

[0037] The preparation method of pectinase hydrolysate 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 0.5-1 h to obtain pectinase hydrolysate.

[0038] The enzymatic hydrolysis conditions are 45–50℃ for 1–2 hours; alternatively, the enzymatic hydrolysis is carried out under stirring conditions of 80–100 r / min and reaction at 50℃ for 1.5 hours.

[0039] (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.

[0040] Optionally, cells are sieved using two layers of sieves. The first layer of sieves has an aperture of 200–250 μm, and the second layer of sieves has an aperture of 50–75 μm. Cassava samples on the second layer of sieves are collected to obtain whole cassava cell powder.

[0041] Further, optionally, a fortified cassava whole-cell powder with lower viscosity can be prepared from cassava whole-cell powder, wherein the preparation method of the fortified cassava whole-cell powder is as follows:

[0042] Fortified cassava whole cell powder is prepared by soaking cassava whole cell powder in calcium ion solution for 20-30 minutes.

[0043] In one embodiment, the calcium ion solution may be one of calcium chloride solution, calcium citrate, calcium phosphate, calcium carbonate, and calcium gluconate. 2+ The concentration is 2% to 5%; optionally, after soaking, the fortified cassava whole cell powder is prepared by centrifugation, wherein the centrifugation speed for dehydration is 5000 rpm and the centrifugation time is 10 to 15 min.

[0044] The beneficial effects of this invention are:

[0045] This invention utilizes pectinase to enzymatically dissolve the thin intermediate layer binding cells together, preparing single, complete cassava whole cells, while simultaneously using Ca... 2+ Solution impregnation of cells enhances the binding capacity between polysaccharide components in the cell wall, strengthening the cell wall. Using these cells as the main raw material, a recombinant rice made from whole cassava cells is prepared via extrusion technology. The method of this invention yields intact whole cassava cells with high separation efficiency. The resulting recombinant rice effectively improves the high viscosity characteristics of cassava starch and exhibits high resistance to digestion.

[0046] Specifically:

[0047] (1) This invention utilizes pectinase to separate cassava whole cells, and the cassava cells prepared have complete cell structure and a high separation rate (70-80%), which is an efficient method for preparing cassava cell powder.

[0048] (2) The cassava cell powder separated by the present invention can effectively retain the nutrients of cassava, and the physical barrier effect of the intact cell wall and the dense cell matrix enhance the starch’s resistance to digestion. At the same time, the viscosity of the separated whole cassava cell powder is significantly reduced compared to cassava starch, which solves the problem of cassava starch being sticky and easy to stick together.

[0049] (3) The cassava whole-cell powder prepared in this invention utilizes Ca 2+Strengthening the cell wall, increasing its strength, and reducing its permeability can improve the cell wall's shear resistance and its physical barrier effect against amylase.

[0050] (4) The recombinant rice prepared by using cassava whole cell powder to replace rice flour has the advantages of good taste, bright color, rich dietary fiber, high nutritional value and resistance to digestion. Moreover, the preparation method is simple to operate, the steps are closely connected, it is green and environmentally friendly, easy to form industrialization, and suitable for widespread application, providing a new idea for the edible processing of cassava resources. Attached Figure Description

[0051] Figure 1 Example 1 is a micrograph of whole-cell cassava powder.

[0052] Figure 2 The viscosity curves are those of whole cassava cell powder, cassava flour, and starch.

[0053] Figure 3 The release curve of recombinant rice glucose.

[0054] Figure 4 Shear resistance of cassava whole-cell powder in Examples 1 and 2. Detailed Implementation

[0055] 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.

[0056] Test method:

[0057] 1. Microscopic observation of cassava samples

[0058] The whole-cell structure of cassava was observed using an optical microscope under normal and polarized light, and the cell wall integrity was observed by staining the cells with 0.1% Congo red.

[0059] 2. Determination of viscosity characteristics of cassava samples

[0060] Cassava cell samples were dried in a 60℃ oven for 24 hours to obtain cassava whole cell powder. The viscosity characteristics of cassava starch, whole powder, and cassava cells were analyzed using a rapid viscosity analyzer. 2g of sample was mixed with 25mL of distilled water in a sample testing aluminum can. The test procedure was as follows: 50℃ for 1min, then the temperature was increased to 95℃ at a rate of 12℃ / min and held for 2.5min. Subsequently, the temperature was decreased to 50℃ at a rate of 12℃ / min and held for 2min. The stirring speed was 960r / min for the first 10s and then maintained at 160r / min until the end of the experiment.

[0061] 3. Determination of the in vitro digestibility of recombinant rice

[0062] The in vitro digestibility of recombinant rice was determined using the Englyst method. 200 mg of sample was weighed and placed in a 50 mL centrifuge tube. 2 mL of distilled water was added and the mixture was shaken and incubated in a boiling water bath for 10 min. After cooling, 4 mL of pepsin solution (20 mg porcine pepsin dissolved in 4 mL of 0.02 M hydrochloric acid solution) was added and the mixture was incubated at 37°C with shaking (150 rpm) for 30 min. 4 mL of acetate buffer (0.5 M, pH 5.2) and 5 glass beads were added and the mixture was incubated at 37°C with shaking for 10 min. Then, 2 mL of mixed enzyme solution (8 g trypsin and 1.96 mL glucoamylase (260 U / mL) dispersed in 44.8 mL of water) was added. At 0, 0.5, 1, 1.5, 2, 2.5, 3, 6, 9, and 12 h, 0.1 mL of the sample was taken and 0.9 mL of 90% ethanol was added to inactivate the enzyme. After centrifugation at 10000 rpm for 5 min, the supernatant was collected, and the glucose content was determined using a glucose oxidase kit (GOD-POD).

[0063] 4. Analysis of the textural properties of recombinant rice

[0064] The textural properties of rice were analyzed using a texture analyzer. The speeds before, during, and after the test were set to 1, 0.5, and 0.5 mm / s, respectively. The compression distance was 75%, the trigger type was set to "Auto", the trigger force was 0.05 N, and the holding time was 5 s. The test results were automatically analyzed and output by the instrument's accompanying software, TE32.

[0065] 5. Determination of cassava cell shear resistance

[0066] 2g of dried cell sample was added to 20mL of distilled water and gelatinized in a boiling water bath for 10min. After cooling, the shear resistance of the sample was measured using a rheometer. The test procedure was as follows: the rotation speed was increased from 0rad / s to 150rad / s within 3min, and then decreased from 150rad / s to 0rad / s at the same rate, forming a thixotropic ring. The size of the thixotropic ring represents the shear resistance of the sample, which reflects the strength of the cell wall. The smaller the thixotropic ring area, the less energy is required to return to the original state, i.e., the stronger the shear resistance. Raw materials used in the examples:

[0067] Fresh cassava was purchased from: Guangxi Kangyi Ecological Agriculture Development Co., Ltd.

[0068] Cassava flour: Fresh cassava is peeled and sliced, dried in an oven at 60℃ for 24 hours, then pulverized using a grinder and collected through an 80-mesh sieve to obtain cassava flour;

[0069] Cassava starch: Peel and cut fresh cassava into chunks, add twice the weight of distilled water, crush in a blender for 15 minutes, sieve the cassava starch through a 300-mesh screen, collect the filtrate, vacuum filter to dehydrate, wash with ethanol, centrifuge to dehydrate, and dry in an oven at 50℃ for 24 hours to obtain cassava starch.

[0070] High amylose corn starch was purchased from Xiangyu 1945, which was purchased from Quanyin Xiangyu (Beijing) Biotechnology Co., Ltd.

[0071] The rice protein powder was purchased from Jiangxi Jinong Biotechnology Co., Ltd.

[0072] The broken rice flour was purchased from Jiangxi Jinong Biotechnology Co., Ltd.

[0073] Pectinase was purchased from Shanghai Yuanye Biotechnology Co., Ltd. (S10007 50000U / g).

[0074] Example 1: Preparation method of cassava whole cell powder

[0075] The steps for preparing cassava whole-cell powder are as follows:

[0076] (1) Peel and cut cassava into chunks: Peel and wash fresh cassava, cut it into chunks (3mm×3mm), and soak it in water;

[0077] (2) Whole-cell isolation of cassava: Pectinase was dissolved in citrate buffer (0.1M pH=3.5) to prepare 1U / 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 1kg:8L. The mixture was stirred continuously at 50℃ (100rpm) for 2h to obtain enzymatically isolated cassava samples.

[0078] (3) Whole cell sieving: The cassava sample prepared in step (2) after enzymatic hydrolysis and separation is rinsed with running water and sieved through a double-layer sieve to separate the cells. 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 unseparated cell clusters on the first layer of sieve are enzymatically hydrolyzed and separated in step (2) until there are no obvious large cassava particles remaining. The whole cassava cells separated on the second layer of sieve are collected and dried to obtain whole cassava cell powder.

[0079] The whole-cell isolation rate of cassava was 75% (isolation rate = dry weight of isolated cells / total dry weight of sample × 100%). A micrograph of the whole-cell powder is shown below. Figure 1 As shown.

[0080] Comparative Example 1: Preparation conditions

[0081] 1. Different enzymatic hydrolysis conditions

[0082] Based on Example 1, the enzymatic hydrolysis conditions in step (2) were changed, while the remaining steps were the same as in Example 1. Whole cassava cells were prepared, and the separation rate was detected, as shown in Table 1.

[0083] Table 1 Different enzymatic hydrolysis conditions

[0084] Enzyme concentration U / mL Material-to-liquid ratio (kg:L) Enzymatic hydrolysis time h Separation rate Combination 1 0.01 1:10 3 46.2％ Combination 2 1 1:2 2 50.1％ Combination 3 10 1:10 2 45％ Combination 4 1 1:15 0.5 35％ Example 1 1 1：8 2 75％

[0085] The results showed that too low an enzyme concentration would lead to incomplete cassava cell separation, leaving a large number of cell clusters remaining; while too high an enzyme concentration would cause cell wall damage, increase cell breakage, and reduce the separation rate; too short an enzymatic hydrolysis time or too low a material-to-liquid ratio would lead to incomplete pectin hydrolysis, resulting in poor cell separation and a reduced separation rate.

[0086] 2. Different screen mesh sizes

[0087] Based on Example 1, the mesh size of the sieve in step (3) of whole cell sieving was changed, and the remaining steps were the same as in Example (1) to prepare cassava whole cells. The viscosity of the sample was tested, as shown in Table 2.

[0088] Table 2. Effect of sieve size on sample viscosity

[0089] First layer of screen (μm) Second layer sieve (μm) Sample viscosity (cP) Separation rate Combination 1 400 250 1060 45％ Combination 2 250 150 1459 52％ Combination 3 150 75 1720 47％ Example 1 250 75 1627 75％

[0090] The results showed that if the sieve aperture is too large, smaller cells will be filtered out, and unseparated cells will be contained, resulting in a lower sample viscosity. If the sieve aperture is too small, larger intact cells will be trapped by the upper sieve, leading to an increase in sample viscosity. At the same time, an unsuitable sieve aperture will reduce the cell separation rate.

[0091] The viscosity of the cassava whole cells, cassava starch, and cassava flour prepared in Example 1 was measured as follows: Figure 2 As shown, the results indicate that the viscosity value of cassava whole cell powder is significantly lower than that of cassava starch and cassava flour, suggesting that the presence of cell walls can inhibit starch swelling, thus the addition of cassava cell powder can reduce the stickiness of reconstituted rice.

[0092] Example 2: Preparation method of fortified cassava whole cell powder

[0093] The steps for preparing whole cassava cells are as follows:

[0094] (1) Peel and cut cassava into chunks: Peel and wash fresh cassava, cut it into chunks (3mm×3mm), and soak it in water;

[0095] (2) Whole-cell isolation of cassava: Pectinase was dissolved in citrate buffer (0.1M pH=3.5) to prepare 1U / 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 1:8. The mixture was stirred continuously at 50℃ (100rpm) for 2h to obtain enzymatically isolated cassava samples.

[0096] (3) Whole cell sieving: The cassava sample prepared in step (2) after enzymatic hydrolysis and separation is rinsed with running water and sieved through a double-layer sieve to separate the cells. 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 unseparated cell clusters on the first layer of sieve are enzymatically hydrolyzed and separated in step (2) until there are no obvious large cassava particles left. The cassava sample on the second layer of sieve is collected to obtain the whole cell sample of cassava.

[0097] (4)Ca 2+ Immersion: The cassava whole cell samples collected in step (3) were immersed in a 5% CaCl2 solution (the concentration of the cassava whole cell samples was 10% w / v) for 30 min, centrifuged to remove excess Ca. 2+ The sediment was collected to obtain fortified cassava whole-cell powder.

[0098] The shear resistance of the cassava cell powder prepared in Example 1 and the enhanced cassava cell powder prepared in Example 2 was tested, and the results are as follows: Figure 4 As shown.

[0099] The results showed that cassava cells were affected by Ca 2+ After strengthening, the thixotropic ring area decreased, indicating that the cell's shear resistance increased and the cell wall strength was enhanced. This can reduce cell wall damage during the extrusion of cassava cell powder and improve the texture and digestibility of recombinant cassava rice.

[0100] Example 3: Preparation of Cassava Whole Cell Powder Recombinant Rice

[0101] The steps for preparing recombinant rice from cassava whole-cell powder are as follows:

[0102] (1) Peel and cut cassava into chunks: Peel and wash fresh cassava, cut it into chunks (3mm×3mm), and soak it in water;

[0103] (2) Whole-cell isolation of cassava: Pectinase was dissolved in citrate buffer (0.1M pH=3.5) to prepare 1U / 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 1:8. The mixture was stirred continuously at 50℃ (100rpm) for 2h to obtain enzymatically isolated cassava samples.

[0104] (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 unseparated cell clusters on the first layer of sieve are enzymatically hydrolyzed and separated in step (2) until there are no obvious large cassava particles remaining. The whole cell sample of cassava is then collected.

[0105] (4)Ca 2+ Immersion: The cassava whole-cell sample (10%) collected in step (3) was immersed in 5% w / v CaCl2 solution for 30 min, centrifuged to remove excess Ca. 2+ The precipitate was collected to obtain fortified cassava whole cells.

[0106] (5) Preparation of recombinant rice: Fortified cassava whole cells, rice protein powder and broken rice powder are mixed evenly at a mass ratio (dry basis) of 7:1:3 to obtain a powder mixture. Distilled water is added to adjust the moisture content of the powder mixture to 30%. After mixing evenly, the mixture is fed into a twin screw extruder. The feeding speed is 3 kg / h, the screw speed is 100 r / min, the die orifice diameter is 5 mm, and the cutting blade speed is 200 r / min. The four temperature sections of the twin screw extruder are set to 45℃, 50℃, 60℃ and 70℃ respectively to prepare the extruded product.

[0107] (6) Fluidized bed drying: The extruded product obtained in step (5) is dried in a hot air fluidized bed until the moisture content is ≤10%, the drying temperature is 100℃ and the drying time is 10min, and cassava whole cell powder recombinant rice is prepared.

[0108] Example 4: Preparation of Cassava Whole Cell Powder Recombinant Rice

[0109] Based on Example 3, step (2) of cassava whole cell separation was changed as follows: pectinase was dissolved in citrate buffer (0.1M pH=3.5) to prepare 5U / mL enzymatic hydrolysate, and 5% w / v ascorbic acid was added. The hydrolysate was activated at 50℃ for 1h 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. The remaining steps were the same as in Example 3 to obtain cassava whole cell powder recombinant rice.

[0110] Example 5: Preparation of Cassava Whole Cell Powder Recombinant Rice

[0111] Based on Example 3, step (4) Ca is modified. 2+ The soaking process was as follows: the cassava whole cell sample (10%) collected in step (3) was soaked in 2% CaCl2 solution for 20 min, and the remaining steps were the same as in Example 3, to prepare cassava whole cell powder recombinant rice.

[0112] Example 6: Preparation of Cassava Whole Cell Powder Recombinant Rice

[0113] Based on Example 3, step (5) of preparing recombinant rice was modified as follows: Fortified cassava whole cells, rice protein powder, and broken rice powder were mixed evenly at a mass ratio (dry basis) of 6:0.5:4 to obtain a powder mixture. Distilled water was added to adjust the moisture content of the powder mixture to 35%. After mixing evenly, the mixture was fed into a twin-screw extruder with a feeding speed of 3 kg / h, a screw rotation speed of 90 r / min, a die orifice diameter of 5 mm, a cutting blade rotation speed of 200 r / min, and the temperature control was set to 45℃, 55℃, 65℃, and 70℃ for the four sections of the twin-screw extruder. The remaining steps were the same as in Example 3, and cassava whole cell powder recombinant rice was prepared.

[0114] Example 7: Preparation of Cassava Whole Cell Powder Recombinant Rice

[0115] Based on Example 3, step (5) of preparing recombinant rice was changed as follows: Fortified cassava whole cells, rice protein powder, and broken rice powder were mixed evenly at a mass ratio (dry basis) of 5:1:5 to obtain a powder mixture. Distilled water was added to adjust the moisture content of the powder mixture to 40%. After mixing evenly, the mixture was fed into a twin-screw extruder with a feeding speed of 3 kg / h, a screw rotation speed of 100 r / min, a die orifice diameter of 5 mm, a cutting blade rotation speed of 200 r / min, and the temperature control was set to 50℃, 60℃, 65℃, and 75℃ for the four sections of the twin-screw extruder. The remaining steps were the same as in Example 3, and cassava whole cell powder recombinant rice was prepared.

[0116] Comparative Example 2: Calcium ion treatment omitted

[0117] Based on Example 3, step (4) was omitted, and the cassava whole cell sample obtained in step (3) was directly mixed with rice protein powder and broken rice. The rest was the same as in Example 3, and cassava whole cell powder recombinant rice was prepared.

[0118] Comparative Example 3: Preparation of Recombinant Rice Using Cassava Starch

[0119] The steps for preparing reconstituted rice by extrusion of cassava flour are as follows:

[0120] (1) Cassava starch, rice protein powder and broken rice flour are mixed evenly in a mass ratio (dry basis) of 7:1:3 to obtain a powder mixture. Distilled water is added to adjust the moisture content of the powder mixture to 30% w / w. After mixing evenly, the mixture is fed into a twin screw extruder. The feeding speed is 3 kg / h, the screw speed is 100 r / min, the die orifice diameter is 5 mm, the cutting blade speed is 200 r / min, and the temperature is controlled by setting the four temperature sections of the twin screw extruder to 45℃, 50℃, 60℃ and 70℃ respectively to obtain the extruded product.

[0121] (2) Fluidized bed drying: The extruded product obtained in step (1) is dried in a hot air fluidized bed until the moisture content is ≤10%, the drying temperature is 100℃ and the drying time is 10min, and cassava starch recombinant rice is prepared.

[0122] Comparative Example 4: Preparation of Recombinant Rice Using Cassava Flour

[0123] Based on Comparative Example 3, the cassava starch was replaced with cassava flour to prepare recombinant rice made from cassava flour.

[0124] Comparative Example 5: Preparation of Recombinant Rice Using High-Amylose Corn Starch

[0125] Based on Comparative Example 3, the cassava starch was replaced with high amylose corn starch to prepare high amylose corn starch recombinant rice.

[0126] Comparative Example 6: Changing the preparation conditions of recombinant rice

[0127] Based on Example 3, step (5) is modified as follows: the reinforced cassava whole cell, rice protein powder, and broken rice powder are mixed evenly at a mass ratio (dry basis) of 7:1:3 to obtain a powder mixture. Distilled water is added to adjust the moisture content of the powder mixture to 45%. After mixing evenly, the mixture is fed into a twin-screw extruder with a feeding speed of 3 kg / h, a screw rotation speed of 200 r / min, a die orifice diameter of 5 mm, a cutting blade rotation speed of 200 r / min, and a temperature control of 60℃, 65℃, 75℃, and 90℃ for the four sections of the twin-screw extruder. The cassava whole cell powder recombinant rice is then prepared.

[0128] Example 8: Testing the performance of recombinant rice

[0129] Examples 3-7, Comparative Examples 2-6, and commercially available rice (Comparative Example 7) were used to analyze the characteristics of reconstituted rice and commercially available rice.

[0130] 1. In vitro digestion characteristics

[0131] The in vitro digestibility characteristics of recombinant rice and commercially available rice were tested, and the results are as follows: Figure 3 As shown.

[0132] The results showed that the addition of cassava cell powder could significantly delay the release of glucose from recombinant rice, and Ca 2+ Strengthening the cell wall can further enable the slow release of glucose, indicating that the presence of the cell wall and the dense cell matrix in cassava cells can hinder the hydrolysis of starch by digestive enzymes, which is of positive significance for the preparation of low glycemic index foods.

[0133] 2. Texture analysis

[0134] The textural properties of recombinant rice and commercially available rice were tested, and the results are shown in Table 3. The results indicate that cassava whole-cell powder recombinant rice has similar textural properties to rice flour and can be used as an excellent substitute for rice.

[0135] Table 3. Texture Analysis Results

[0136]

[0137]

[0138] 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 recombinant rice, characterized in that, The preparation method is as follows: Fortified cassava whole-cell powder, rice protein powder, and broken rice powder are mixed evenly at a mass ratio (dry basis) of 5~7:0.5~1:3~5 to obtain a powder mixture. Water is added to make the moisture content of the powder mixture reach 30%~40% w / w. After mixing evenly, the mixture is fed into a twin-screw extruder to prepare an extruded product. The extruded product is dried to prepare recombinant cassava whole-cell powder rice, wherein the moisture content of the recombinant cassava whole-cell powder rice is ≤10%. The preparation methods for fortified cassava whole-cell powder include: (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 to prepare enzymatically hydrolyzed cassava samples. The preparation method of pectinase hydrolysate was as follows: pectinase was dissolved in citrate buffer to make the final concentration of pectinase 0.5~5U / mL; 3~5% w / v ascorbic acid was added, and the mixture was activated at 45~50℃ for 0.5~1h to prepare pectinase hydrolysate; the hydrolysis conditions were 45~50℃ for 1~2h. (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. Two layers of sieves were used to sieve the cells. The first layer of sieve had a pore size of 200~250μm and the second layer of sieve had a pore size of 50~75μm. The cassava samples on the second layer of sieve were collected to obtain whole cell powder. (3) Strengthening cassava whole cell powder: Soak cassava whole cell powder in calcium ion solution for 20-30 minutes; wherein the concentration of cassava whole cell powder in calcium ion solution is 10-15% w / v.

2. The recombinant rice according to claim 1, characterized in that, The parameters of the twin-screw extruder are set as follows: feeding speed is 5~8 kg / h, screw speed is 90~100 r / min, die diameter is 4~8 mm, and cutting blade speed is 200~250 r / min; the four temperature ranges of the twin-screw extruder are 45~50℃, 55~60℃, 60~65℃, and 70~75℃, respectively.

3. The recombinant rice according to claim 1, characterized in that, The drying conditions are 90~100℃ and the drying time is 10~15min.

4. The application of the recombinant rice according to claim 1 in the preparation of the product, characterized in that, The product in question is a food product.

5. The application according to claim 4, characterized in that, The food in question is a starch-based food, including: starch, bread, noodles, steamed buns, dumplings, biscuits, or cakes.

6. A product characterized in that, The product contains one or more of the recombinant rice as described in any one of claims 1 to 3; the product is a food product.

7. The product according to claim 6, characterized in that, The food in question is a starch-based food, including: starch, bread, noodles, steamed buns, dumplings, biscuits, or cakes.

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