Impurity removal production process of sweet potato starch

Abstract

The invention discloses an impurity removal production process of sweet potato starch. The impurity removal production process comprises the following steps: S1, pretreatment; s2, crushing and screening; s3, centrifugal separation and impurity removal; s4, blending the pulp; s5, standing and precipitating; s6, precipitating and fermenting; s7, cyclone desanding and refining; and S8, drying. A three-stage countercurrent cleaning and water circulation system is adopted, water is saved by 30%, and the discharge amount of waste water is reduced. According to the method, multi-stage screening and centrifugation synergic impurity removal are adopted, the starch extraction rate is larger than or equal to 92%, and protein residues are smaller than or equal to 0.3%. The number of rotational flow stages (6-10 stages) is automatically adjusted according to the silt content, and the sand removal efficiency is larger than or equal to 99.5%.

Description

Technical Field

[0001] The invention relates to the technical field of sweet potato starch processing, and more particularly to a production process for removing impurities from sweet potato starch. Background Art

[0002] Sweet potatoes are rich in nutrients. They contain large amounts of starch, vitamin C, vitamin B1, vitamin B2, vitamin E, carotene, dietary fiber, and various amino acids (especially lysine, which is rare in rice and flour). They also contain minerals such as calcium, phosphorus, iron, and potassium, as well as substances such as mucin, dehydroepiandrosterone, a quasi-female hormone, and selenium, which have anti-cancer and anti-cancer properties. Sweet potatoes offer a balanced and comprehensive nutritional profile, with nutritional value comparable to that of rice and flour. Fresh potatoes are gaining renewed attention in the human diet. In recent years, sweet potato starch has been in short supply.

[0003] At present, most of the impurity removal processes of domestic sweet potato deep processing enterprises use a single sweet potato starch desander or a desander plus a cyclone to remove impurities from crude sweet potato starch milk. This process is simple and has a poor impurity removal effect. The ash, protein, and pectin content of the filtered sweet potato starch is still high, and the fineness cannot be further improved, affecting the quality of the sweet potato starch and its products.

[0004] The existing sweet potato starch extraction process is to wash, crush, filter and dry the sweet potatoes to obtain sweet potato starch. However, the sweet potato starch produced through the above process steps contains many impurities, such as high crude fiber and protein content, which reduces the purity of the sweet potato starch, affects the grade of the obtained sweet potato starch, and reduces the economic benefits of the sweet potato starch. Summary of the Invention

[0005] In view of this, the present invention provides a production process for removing impurities from sweet potato starch to solve the technical problems encountered in the background technology.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A production process for removing impurities from sweet potato starch comprises the following steps:

[0008] S1 preprocessing

[0009] Fresh sweet potatoes are selected, and the sweet potatoes are selected from high-starch varieties. The sweet potatoes undergo three-stage countercurrent washing to remove surface sediment; the washing water is recycled, and the end-of-line discharge water is used for the initial rinse of the raw materials; the sweet potato skin is removed through a peeling device and cut into small pieces;

[0010] S2 Crushing and Screening

[0011] A sawtooth crusher is used to crush the sweet potato pieces into 1-3mm particles to release the starch; the crushed pulp is subjected to three-stage vibration screening to separate the crude fiber;

[0012] S3 centrifugal separation and impurity removal

[0013] The slurry after screening enters the horizontal centrifuge, where it is centrifuged to separate protein and fine fibers, and the supernatant is collected for reuse;

[0014] S4 pulping

[0015] Add acid pulp and water to the supernatant to control the concentration and acidity of the pulp water and further separate starch and protein;

[0016] S5 static sedimentation

[0017] The slurry solution is allowed to settle for a period of time, and the mixed solution on the upper layer is discharged;

[0018] S6 precipitation fermentation

[0019] Add water to the lower layer of precipitate remaining in step S5, and ferment it at a certain temperature. After fermentation, let it stand for a period of time, drain the upper layer of the sour pulp solution and save it for future use, drain the starch precipitate, and filter it using a filter screen;

[0020] S7 cyclone sand removal and refining

[0021] The filtered starch is passed through a multi-stage cyclone group to remove fine impurities to obtain refined starch milk;

[0022] S8 Drying

[0023] The refined starch milk is vacuum dehydrated and then dried with low-temperature air flow to obtain the finished starch.

[0024] Preferably, the three-stage vibration screening in step S2 is to crush the slurry through three-stage vibration screening of 80 mesh, 120 mesh and 200 mesh.

[0025] Preferably, the centrifugal separation speed in step S3 is 2000-3000 rpm.

[0026] Preferably, the pH of the sour pulp in step S4 is 3.5-4.0.

[0027] Preferably, the concentration of the starch solution in step S4 is 4.1-4.5 degrees Baume, and the content of the added Physalis solution is 1.6-2.0% of the starch solution.

[0028] Preferably, the time for static precipitation in step S5 is 40-50 minutes.

[0029] Preferably, the fermentation treatment in step S6 is stirring at 20-25° C. for 24 hours, and the standing time is 30-40 minutes.

[0030] Preferably, the cyclone sand removal in step S7 uses a 6-10 stage cyclone group with an operating pressure of 0.4-0.6 MPa.

[0031] Preferably, the vacuum dehydration in step S8 controls the moisture content to ≤40%, and the temperature of the low-temperature airflow drying is ≤60°C.

[0032] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following technical effects:

[0033] 1. The present invention adopts a three-stage countercurrent cleaning + water circulation system: saving 30% of water and reducing wastewater discharge.

[0034] 2. The present invention adopts multi-stage screening + centrifugal synergistic impurity removal: starch extraction rate ≥ 92%, protein residue ≤ 0.3%.

[0035] 3. Dynamic adjustment of cyclone group: automatically adjust the cyclone level (6-10 levels) according to the sediment content, and the sand removal efficiency is ≥99.5%. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments 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.

[0037] Example 1

[0038] The present embodiment provides a production process for removing impurities from sweet potato starch, comprising the following steps:

[0039] S1 preprocessing

[0040] Fresh sweet potatoes are selected, and the sweet potatoes are selected from high-starch varieties. The sweet potatoes undergo three-stage countercurrent washing to remove surface sediment; the washing water is recycled, and the end-of-line discharge water is used for the initial rinse of the raw materials; the sweet potato skin is removed through a peeling device and cut into small pieces;

[0041] S2 Crushing and Screening

[0042] A sawtooth crusher is used to crush the sweet potato pieces into 3mm particles to release the starch; the crushed pulp is screened through three levels of vibration with 80 mesh, 120 mesh, and 200 mesh to separate the crude fiber;

[0043] S3 centrifugal separation and impurity removal

[0044] The slurry after screening enters the horizontal centrifuge, and is centrifuged at 2000rpm to separate the protein and fine fibers, and the supernatant is collected for reuse;

[0045] S4 pulping

[0046] Adding physalis and water to the supernatant to control the concentration and acidity of the slurry to further separate starch and protein; the pH of the physalis is 3.5, the concentration of the starch solution is 4.5 degrees Baume, and the content of the added physalis solution is 2.0% of the starch solution content;

[0047] S5 static sedimentation

[0048] The slurry solution was allowed to settle for 50 minutes, and the upper mixed solution was discharged;

[0049] S6 precipitation fermentation

[0050] Add water to the lower layer of precipitate remaining in step S5, and stir at 20°C for 24 hours. 30 minutes after fermentation, drain the upper layer of the sour pulp solution and save it for future use. Then drain the starch precipitate and filter it using a filter sieve.

[0051] S7 cyclone sand removal and refining

[0052] The filtered starch is passed through a 6-10 stage cyclone group (pressure 0.4 MPa) to remove fine impurities to obtain refined starch milk;

[0053] S8 Drying

[0054] The refined starch milk is vacuum dehydrated to a moisture content of ≤40%, and then dried with a low-temperature air flow to a temperature of ≤60°C to obtain finished starch.

[0055] Example 2

[0056] The present embodiment provides a production process for removing impurities from sweet potato starch, comprising the following steps:

[0057] S1 preprocessing

[0058] Fresh sweet potatoes are selected, and the sweet potatoes are selected from high-starch varieties. The sweet potatoes undergo three-stage countercurrent washing to remove surface sediment; the washing water is recycled, and the end-of-line discharge water is used for the initial rinse of the raw materials; the sweet potato skin is removed through a peeling device and cut into small pieces;

[0059] S2 Crushing and Screening

[0060] A sawtooth crusher is used to crush the sweet potato pieces into 1mm particles to release the starch; the crushed pulp is screened through three levels of vibration with 80 mesh, 120 mesh, and 200 mesh to separate the crude fiber;

[0061] S3 centrifugal separation and impurity removal

[0062] The slurry after screening enters the horizontal centrifuge, and is centrifuged at 3000rpm to separate the protein and fine fibers, and the supernatant is collected for reuse;

[0063] S4 pulping

[0064] Adding physalis and water to the supernatant to control the concentration and acidity of the slurry to further separate starch and protein; the pH of the physalis is 4.0, the concentration of the starch solution is 4.1 degrees Baume, and the content of the added physalis solution is 1.6% of the starch solution content;

[0065] S5 static sedimentation

[0066] The slurry solution was allowed to settle for 40 minutes, and the mixed solution on the upper layer was discharged;

[0067] S6 precipitation fermentation

[0068] Add water to the lower layer of precipitate remaining in step S5, and stir at 25°C for 24 hours. 30-40 minutes after fermentation, drain the upper layer of the sour pulp solution and save it for future use. Then drain the starch precipitate and filter it using a filter sieve.

[0069] S7 cyclone sand removal and refining

[0070] The filtered starch is passed through a 6-10 stage cyclone group (pressure 0.6 MPa) to remove fine impurities to obtain refined starch milk;

[0071] S8 Drying

[0072] The refined starch milk is vacuum dehydrated to a moisture content of ≤40%, and then dried with a low-temperature air flow to a temperature of ≤60°C to obtain finished starch.

[0073] Example 3

[0074] The present embodiment provides a production process for removing impurities from sweet potato starch, comprising the following steps:

[0075] S1 preprocessing

[0076] Fresh sweet potatoes are selected, and the sweet potatoes are selected from high-starch varieties. The sweet potatoes undergo three-stage countercurrent washing to remove surface sediment; the washing water is recycled, and the end-of-line discharge water is used for the initial rinse of the raw materials; the sweet potato skin is removed through a peeling device and cut into small pieces;

[0077] S2 Crushing and Screening

[0078] A sawtooth crusher is used to crush the sweet potato pieces into 2mm particles to release the starch; the crushed pulp is screened through three levels of vibration with 80 mesh, 120 mesh, and 200 mesh to separate the crude fiber;

[0079] S3 centrifugal separation and impurity removal

[0080] The slurry after screening enters the horizontal centrifuge, and is centrifuged at 2500rpm to separate the protein and fine fibers, and the supernatant is collected for reuse;

[0081] S4 pulping

[0082] Adding physalis and water to the supernatant to control the concentration and acidity of the slurry to further separate starch and protein; the pH of the physalis is 3.7, the concentration of the starch solution is 4.3 degrees Baume, and the content of the added physalis solution is 1.8% of the starch solution content;

[0083] S5 static sedimentation

[0084] The slurry solution was allowed to settle for 45 minutes, and the mixed solution on the upper layer was discharged;

[0085] S6 precipitation fermentation

[0086] Add water to the lower layer of precipitate remaining in step S5, and stir at 23°C for 24 hours. 35 minutes after fermentation, drain the upper layer of the sour pulp solution and save it for future use. Then drain the starch precipitate and filter it using a filter sieve.

[0087] S7 cyclone sand removal and refining

[0088] The filtered starch is passed through a 6-10 stage cyclone group (pressure 0.5 MPa) to remove fine impurities to obtain refined starch milk;

[0089] S8 Drying

[0090] The refined starch milk is vacuum dehydrated to a moisture content of ≤40%, and then dried with a low-temperature air flow to a temperature of ≤60°C to obtain finished starch.

[0091] Comparative Example 1

[0092] The production process is the same as that of Example 3, except that the screening and centrifugation steps are not performed.

[0093] Comparative Example 2

[0094] The production process is the same as that of Example 3, except that the cyclone desanding and refining step is not performed.

[0095] The moisture, ash, protein and whiteness of the sweet potato starch in Examples 1-3 and Comparative Examples 1-2 were measured using the method in GB / T 34321-2017. The results are shown in Table 1.

[0096] Moisture ash content protein Whiteness Example 1 12.1 0.15 0.12 92.1 Example 2 12.8 0.14 0.15 92.5 Example 3 11.5 0.11 0.11 93.2 Comparative Example 1 13.1 0.22 0.33 81.2 Comparative Example 2 12.9 0.25 0.22 82.3

[0097] As can be seen from the table above, the technical solution of the present invention can increase the starch whiteness to over 92%, the ash content to ≤0.15%, and the protein residue to ≤0.3%. The resulting sweet potato starch has high purity.

[0098] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0099] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A sweet potato starch impurity removal production process, characterized in that, The following steps are involved: S1 preprocessing Fresh sweet potatoes are selected, and the sweet potatoes are selected from high-starch varieties. The sweet potatoes undergo three-stage countercurrent washing to remove surface sediment; the washing water is recycled, and the end-of-line discharge water is used for the initial rinse of the raw materials; the sweet potato skin is removed through a peeling device and cut into small pieces; S2 Crushing and Screening A sawtooth crusher is used to crush the sweet potato pieces into 1-3mm particles to release the starch; the crushed pulp is subjected to three-stage vibration screening to separate the crude fiber; S3 centrifugal separation and impurity removal The slurry after screening enters the horizontal centrifuge, where it is centrifuged to separate protein and fine fibers, and the supernatant is collected for reuse; S4 pulping Add acid pulp and water to the supernatant to control the concentration and acidity of the pulp water and further separate starch and protein; S5 static sedimentation The slurry solution is allowed to settle for a period of time, and the mixed solution on the upper layer is discharged; S6 precipitation fermentation Add water to the lower layer of precipitate remaining in step S5, and ferment it at a certain temperature. After fermentation, let it stand for a period of time, drain the upper layer of the sour pulp solution and save it for future use, drain the starch precipitate, and filter it using a filter screen; S7 cyclone sand removal and refining The filtered starch is passed through a multi-stage cyclone group to remove fine impurities to obtain refined starch milk; S8 Drying The refined starch milk is vacuum dehydrated and then dried with low-temperature air flow to obtain the finished starch.

2. A sweet potato starch impurity removal production process according to claim 1, characterized in that, The three-stage vibration screening in step S2 is to crush the slurry through three-stage vibration screening of 80 mesh, 120 mesh and 200 mesh.

3. A process for removing impurities from sweet potato starch according to claim 1, characterized in that: The centrifugal separation speed in step S3 is 2000-3000 rpm.

4. A process for removing impurities from sweet potato starch according to claim 1, characterized in that: The pH of the syrup in step S4 is 3.5-4.

0.

5. A process for removing impurities from sweet potato starch according to claim 4, characterized in that: The concentration of the starch solution in step S4 is 4.1-4.5 degrees Baume, and the content of the added Physalis solution is 1.6-2.0% of the starch solution.

6. A sweet potato starch impurity removal production process according to claim 1, characterized in that, The time for static precipitation in step S5 is 40-50 minutes.

7. A sweet potato starch impurity removal production process according to claim 1, characterized in that, The fermentation treatment in step S6 is stirring at 20-25° C. for 24 hours, and the standing time is 30-40 minutes.

8. A process for removing impurities from sweet potato starch according to claim 1, characterized in that: The cyclone sand removal in step S7 uses a 6-10 stage cyclone group with an operating pressure of 0.4-0.6 MPa.

9. A process for removing impurities from sweet potato starch according to claim 1, characterized in that: The vacuum dehydration in step S8 controls the moisture content to ≤40%, and the temperature of the low-temperature airflow drying is ≤60°C.