Preparation method of tamarind polysaccharide

Abstract

The invention discloses a preparation method of tamarind polysaccharide, and belongs to the technical field of food processing. The method mainly comprises the following steps: pretreating, pulping, fermenting, centrifuging, purifying, extracting, centrifuging, concentrating, drying and crushing to finally obtain the refined tamarind polysaccharide. According to the method, a biological fermentation method and a multi-stage water extraction method are combined for extraction, so that the extraction efficiency of the tamarind polysaccharide is improved, and meanwhile, the extraction efficiency is further improved by combining with ultrasonic treatment; non-chemical means are adopted in the preparation process, and the green technology is achieved; and compared with the conventional tamarind polysaccharide, the prepared refined tamarind polysaccharide has better appearance and transparency and higher viscosity.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to a method for preparing tamarind polysaccharide. Background Art

[0002] The tamarind kernel contains rich polysaccharides, proteins, fats and other ingredients, among which the polysaccharide content is as high as more than 60%. Tamarind polysaccharides can be obtained by processing them, which are often used as thickeners, binders, stabilizers, gelling agents, etc. and are widely used in food, medicine, tobacco, batteries and other industries. At present, protein and fat are the components that need to be removed during the extraction process of tamarind polysaccharides. Among them, fat removal is easier, while protein removal is more difficult. Due to the incomplete removal of impurities such as protein, it is easy to cause the product to have quality defects such as yellowish appearance, low solution transparency, low viscosity and gelling properties.

[0003] Traditional tamarind polysaccharide extraction methods include organic acid extraction, water extraction, etc. The traditional organic acid extraction method often has defects such as low extraction efficiency and purity of the target product, high cost or environmental pollution. The traditional water extraction method can only extract part of the polysaccharide components due to the single conditions, resulting in low extraction efficiency. Summary of the invention

[0004] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a method for preparing tamarind polysaccharide, which improves the extraction efficiency of tamarind polysaccharide, improves the appearance, solution transparency and viscosity of tamarind polysaccharide, and the preparation method is green and clean.

[0005] Technical solution: To achieve the above purpose, the present invention adopts the following technical solution:

[0006] A method for preparing tamarind polysaccharide comprises the following steps:

[0007] (1) Pretreatment: processing tamarind kernels to obtain tamarind kernel powder;

[0008] (2) Pulping: Grind the tamarind kernel powder with water to make a slurry;

[0009] (3) fermentation: adding lactic acid bacteria to the tamarind kernel slurry for fermentation;

[0010] (4) Centrifugation: centrifuging the fermented tamarind kernel slurry and collecting the supernatant;

[0011] (5) Purification: purifying the supernatant and collecting the retentate;

[0012] (6) Extraction: The retentate is heated to different temperatures for multi-stage extraction, supplemented by certain physical means;

[0013] (7) Centrifugation: centrifuge the extracted liquid and collect the supernatant;

[0014] (8) Concentration: Concentrating the supernatant;

[0015] (9) Drying: Drying the concentrated liquid;

[0016] (10) Crushing: The dried sample is crushed to obtain refined tamarind polysaccharide.

[0017] In the above steps, the processing steps in step (1) include washing, soaking, drying, shelling, crushing and screening;

[0018] The amount of water required for pulping in step (2) is 10-20 times the mass of the tamarind kernel powder;

[0019] The lactic acid bacteria in step (3) is Lactobacillus delbrueckii subsp. bulgaricus (purchased from Chr. Hansen (Beijing) Trading Co., Ltd.), the addition amount is 0.01-0.05% (w / v), the fermentation temperature is 38-45° C., and the fermentation time is 4-12 h;

[0020] The centrifugal speed in step (4) is 3000-5000 rpm, and the time is 10-30 min;

[0021] In step (5), purification is performed by dialysis, the dialysis time is 24-48 hours, and the molecular weight of the dialysis bag is 8000-10000Da;

[0022] In step (6), the heating temperature is 50-95° C., the heating time is 0.5-1 h, and the physical means is ultrasonic treatment with a power of 1000 W;

[0023] The centrifugal speed in step (7) is 8000-10000 rpm, and the time is 10-30 min;

[0024] The temperature in step (8) is 50-60°C and the time is 1-2h;

[0025] The drying in step (9) is vacuum freeze drying, the drying temperature is -40 to -60°C, and the drying time is 24 to 48 hours;

[0026] The crushing mesh size in step (10) is 100-200 mesh.

[0027] Beneficial effects: The invention provides a method for preparing tamarind polysaccharide, which adopts a biological fermentation method. During the fermentation process, lactic acid bacteria utilize carbon water (mainly glucose) in the slurry to ferment and produce lactic acid, and the pH of the system is continuously reduced. The protein component in the tamarind kernel slurry will approach the isoelectric point and denature and precipitate, and then can be separated in the subsequent process to achieve the purpose of removing the protein, thereby improving the extraction efficiency of tamarind polysaccharide and avoiding the use of a large amount of organic reagents, which is conducive to reducing production costs; at the same time, combined with graded water extraction and ultrasonic treatment, the extraction efficiency of tamarind polysaccharide is further improved; the whole process is carried out by non-chemical means, realizing green production, and the prepared refined tamarind polysaccharide has better appearance and transparency and higher viscosity than conventional tamarind polysaccharide, thereby providing a new method for preparing refined tamarind polysaccharide. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Attached Figure 1 The figure is a schematic diagram of the process for preparing tamarind polysaccharide by biological fermentation, multi-stage water extraction and high pressure treatment in an embodiment of the present invention.

[0029] Attached Figure 2 This is a schematic diagram of the process flow for preparing tamarind polysaccharides using conventional organic acid method and hot water extraction method, from left to right are organic acid method and hot water extraction method. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0031] The Lactobacillus delbrueckii subspecies bulgaricus used below was purchased from Chr. Hansen (Beijing) Trading Co., Ltd. The Lactobacillus delbrueckii subspecies bulgaricus used is one of the species with the strongest acid-producing ability among lactic acid bacteria. It can produce sufficient lactic acid under suitable conditions, accelerate the reduction of the pH of the system, improve production efficiency, and also play a certain role in decomposing protein.

[0032] As attached Figure 1 As shown, a method for preparing refined tamarind polysaccharide comprises the following steps:

[0033] Pretreatment → pulping → fermentation → centrifugation → purification → concentration → drying → crushing

[0034] The specific steps are as follows:

[0035] (1) Pretreatment: washing, soaking, drying, shelling, crushing, and sieving the tamarind kernels to obtain tamarind kernel powder;

[0036] (2) pulping: adding 10-20 times the weight of water to the processed tamarind kernel powder for grinding to prepare tamarind kernel pulp;

[0037] (3) fermentation: adding 0.01% (w / v) Lactobacillus delbrueckii subsp. bulgaricus to the tamarind kernel slurry for fermentation at a temperature of 40-42° C. for 4 h;

[0038] (4) Centrifugation: centrifuge the tamarind kernel slurry at 3000-5000 rpm for 10-30 min, and collect the supernatant;

[0039] (5) Purification: Purify the supernatant using an 8000-10000Da dialysis bag for 24-48 hours and collect the retentate;

[0040] (6) Concentration: Concentrate the retentate at 50-60° C. for 1-2 h using a rotary evaporator;

[0041] (7) Drying: The concentrated liquid is subjected to vacuum freeze drying at -40 to -60°C for 24 to 48 hours.

[0042] (8) Crushing: crush the dried sample into 100-200 meshes to obtain refined tamarind polysaccharide.

[0043] Example 2

[0044] A method for preparing tamarind polysaccharide, comprising the following steps:

[0045] Pretreatment → pulping → fermentation → centrifugation → purification → concentration → drying → crushing

[0046] The specific steps are as follows:

[0047] (1) Pretreatment: washing, soaking, drying, shelling, crushing, and sieving the tamarind kernels to obtain tamarind kernel powder;

[0048] (2) pulping: adding 10-20 times the weight of water to the processed tamarind kernel powder for grinding to prepare tamarind kernel pulp;

[0049] (3) fermentation: adding 0.02% (w / v) Lactobacillus delbrueckii subsp. bulgaricus to the tamarind kernel slurry for fermentation at a temperature of 38-45° C. for 4 h;

[0050] (4) Centrifugation: centrifuge the tamarind kernel slurry at 3000-5000 rpm for 10-30 min, and collect the supernatant;

[0051] (5) Purification: Purify the supernatant using an 8000-10000Da dialysis bag for 24-48 hours and collect the retentate;

[0052] (6) Concentration: Concentrate the retentate at 50-60° C. for 1-2 h using a rotary evaporator;

[0053] (7) Drying: The concentrated liquid is subjected to vacuum freeze drying at -40 to -60°C for 24 to 48 hours.

[0054] (8) Crushing: crush the dried sample into 100-200 meshes to obtain refined tamarind polysaccharide.

[0055] Example 3

[0056] A method for preparing tamarind polysaccharide, comprising the following steps:

[0057] Pretreatment → pulping → fermentation → centrifugation → purification → concentration → drying → crushing

[0058] The specific steps are as follows:

[0059] (1) Pretreatment: washing, soaking, drying, shelling, crushing, and sieving the tamarind kernels to obtain tamarind kernel powder;

[0060] (2) pulping: adding 10-20 times the weight of water to the processed tamarind kernel powder for grinding to prepare tamarind kernel pulp;

[0061] (3) fermentation: adding 0.02% (w / v) Lactobacillus delbrueckii subsp. bulgaricus to the tamarind kernel slurry for fermentation at a temperature of 40-42° C. for 4-12 h;

[0062] (4) Centrifugation: centrifuge the tamarind kernel slurry at 3000-5000 rpm for 10-30 min, and collect the supernatant;

[0063] (5) Purification: Purify the supernatant using an 8000-10000Da dialysis bag for 24-48 hours and collect the retentate;

[0064] (6) Concentration: Concentrate the retentate at 50-60° C. for 1-2 h using a rotary evaporator;

[0065] (7) Drying: The concentrated liquid is subjected to vacuum freeze drying at -40 to -60°C for 24 to 48 hours.

[0066] (8) Crushing: crush the dried sample into 100-200 meshes to obtain refined tamarind polysaccharide.

[0067] The tamarind polysaccharide yields of samples prepared under different fermentation conditions can be seen in Table 1. It can be seen that increasing the amount of lactic acid bacteria added and extending the fermentation time can increase the tamarind polysaccharide yield, while changing the fermentation temperature has little effect on the results. When the amount of lactic acid bacteria added is 0.02-0.05%, the fermentation temperature is 40-42°C, and the fermentation time is 8-12h, the tamarind polysaccharide yield of the prepared samples is significantly improved.

[0068] Table 1 Yield of tamarind polysaccharides under different fermentation conditions

[0069]

[0070]

[0071] Note: Different lowercase letters in the same column indicate significant differences between the corresponding data (P<0.05).

[0072] Example 4

[0073] A method for preparing refined tamarind polysaccharide, comprising the following steps:

[0074] Pretreatment → pulping → fermentation → centrifugation → extraction → centrifugation → purification → concentration → drying → crushing

[0075] The specific steps are as follows:

[0076] (1) Pretreatment: washing, soaking, drying, shelling, crushing, and sieving the tamarind kernels to obtain tamarind kernel powder;

[0077] (2) pulping: adding 10-20 times the weight of water to the processed tamarind kernel powder for grinding to prepare tamarind kernel pulp;

[0078] (3) fermentation: adding 0.02% (w / v) Lactobacillus delbrueckii subsp. bulgaricus to the tamarind seed slurry for fermentation at a temperature of 40-42° C. for 8-12 h;

[0079] (4) Centrifugation: centrifuge the tamarind kernel slurry at 3000-5000 rpm for 10-30 min, and collect the supernatant;

[0080] (5) Purification: Purify the supernatant using an 8000-10000Da dialysis bag for 24-48 hours and collect the retentate;

[0081] (6) Extraction: Heat the retentate to 80-90°C for 0.5-1h;

[0082] (7) Centrifugation: centrifuge the feed solution at 8000-10000 rpm for 10-30 min and collect the supernatant;

[0083] (8) Concentration: Concentrate the supernatant using a rotary evaporator at 50-60° C. for 1-2 h;

[0084] (9) Drying: The concentrated liquid is subjected to vacuum freeze drying at -40 to -60°C for 24 to 48 hours;

[0085] (10) Grinding: Grind the dried sample into 100-200 meshes to obtain refined tamarind polysaccharide.

[0086] Example 5

[0087] A method for preparing refined tamarind polysaccharide, comprising the following steps:

[0088] Pretreatment → pulping → fermentation → centrifugation → extraction → centrifugation → purification → concentration → drying → crushing

[0089] The specific steps are as follows:

[0090] (1) Pretreatment: washing, soaking, drying, shelling, crushing, and sieving the tamarind kernels to obtain tamarind kernel powder;

[0091] (2) pulping: adding 10-20 times the weight of water to the processed tamarind kernel powder for grinding to prepare tamarind kernel pulp;

[0092] (3) fermentation: adding 0.02% (w / v) Lactobacillus delbrueckii subsp. bulgaricus to the tamarind seed slurry for fermentation at a temperature of 40-42° C. for 8-12 h;

[0093] (4) Centrifugation: centrifuge the tamarind kernel slurry at 3000-5000 rpm for 10-30 min, and collect the supernatant;

[0094] (5) Purification: Purify the supernatant using an 8000-10000Da dialysis bag for 24-48 hours and collect the retentate;

[0095] (6) Extraction: Heat the retentate to 75-85°C and 85-95°C, with each heating time being 20-30 min;

[0096] (7) Centrifugation: centrifuge the feed solution at 8000-10000 rpm for 10-30 min and collect the supernatant;

[0097] (8) Concentration: Concentrate the supernatant using a rotary evaporator at 50-60° C. for 1-2 h;

[0098] (9) Drying: The concentrated liquid is subjected to vacuum freeze drying at -40 to -60°C for 24 to 48 hours;

[0099] (10) Grinding: Grind the dried sample into 100-200 meshes to obtain refined tamarind polysaccharide.

[0100] Example 6

[0101] A method for preparing tamarind polysaccharide, comprising the following steps:

[0102] Pretreatment → pulping → fermentation → centrifugation → extraction → centrifugation → purification → concentration → drying → crushing

[0103] The specific steps are as follows:

[0104] (1) Pretreatment: washing, soaking, drying, shelling, crushing, and sieving the tamarind kernels to obtain tamarind kernel powder;

[0105] (2) pulping: adding 10-20 times the weight of water to the processed tamarind kernel powder for grinding to prepare tamarind kernel pulp;

[0106] (3) fermentation: adding 0.02% (w / v) Lactobacillus delbrueckii subsp. bulgaricus to the tamarind seed slurry for fermentation at a temperature of 40-42° C. for 8-12 h;

[0107] (4) Centrifugation: centrifuge the tamarind kernel slurry at 3000-5000 rpm for 10-30 min, and collect the supernatant;

[0108] (5) Purification: Purify the supernatant using an 8000-10000Da dialysis bag for 24-48 hours and collect the retentate;

[0109] (6) Extraction: The retentate was heated to 60-75°C, 75-90°C, and 90-95°C, respectively, with each heating time being 10-20 min;

[0110] (7) Centrifugation: centrifuge the feed solution at 8000-10000 rpm for 10-30 min and collect the supernatant;

[0111] (8) Concentration: Concentrate the supernatant using a rotary evaporator at 50-60° C. for 1-2 h;

[0112] (9) Drying: The concentrated liquid is subjected to vacuum freeze drying at -40 to -60°C for 24 to 48 hours;

[0113] (10) Grinding: Grind the dried sample into 100-200 meshes to obtain refined tamarind polysaccharide.

[0114] Example 7

[0115] A method for preparing refined tamarind polysaccharide, comprising the following steps:

[0116] Pretreatment → pulping → fermentation → centrifugation → extraction → centrifugation → purification → concentration → drying → crushing

[0117] The specific steps are as follows:

[0118] (1) Pretreatment: washing, soaking, drying, shelling, crushing, and sieving the tamarind kernels to obtain tamarind kernel powder;

[0119] (2) pulping: adding 10-20 times the weight of water to the processed tamarind kernel powder for grinding to prepare tamarind kernel pulp;

[0120] (3) fermentation: adding 0.02% (w / v) Lactobacillus delbrueckii subsp. bulgaricus to the tamarind seed slurry for fermentation at a temperature of 40-42° C. for 8-12 h;

[0121] (4) Centrifugation: centrifuge the tamarind kernel slurry at 3000-5000 rpm for 10-30 min, and collect the supernatant;

[0122] (5) Purification: Purify the supernatant using an 8000-10000Da dialysis bag for 24-48 hours and collect the retentate;

[0123] (6) Extraction: The retentate is heated to 50-65°C, 65-80°C, 80-90°C, and 90-95°C, respectively, with each heating time being 5-20 min;

[0124] (7) Centrifugation: centrifuge the feed solution at 8000-10000 rpm for 10-30 min and collect the supernatant;

[0125] (8) Concentration: Concentrate the supernatant using a rotary evaporator at 50-60° C. for 1-2 h;

[0126] (9) Drying: The concentrated liquid is subjected to vacuum freeze drying at -40 to -60°C for 24 to 48 hours;

[0127] (10) Grinding: Grind the dried sample into 100-200 meshes to obtain refined tamarind polysaccharide.

[0128] Example 8

[0129] A method for preparing refined tamarind polysaccharide, comprising the following steps:

[0130] Pretreatment → pulping → fermentation → centrifugation → extraction → centrifugation → purification → concentration → drying → crushing

[0131] The specific steps are as follows:

[0132] (1) Pretreatment: washing, soaking, drying, shelling, crushing, and sieving the tamarind kernels to obtain tamarind kernel powder;

[0133] (2) pulping: adding 10-20 times the weight of water to the processed tamarind kernel powder for grinding to prepare tamarind kernel pulp;

[0134] (3) fermentation: adding 0.02% (w / v) Lactobacillus delbrueckii subsp. bulgaricus to the tamarind seed slurry for fermentation at a temperature of 40-42° C. for 8-12 h;

[0135] (4) Centrifugation: centrifuge the tamarind kernel slurry at 3000-5000 rpm for 10-30 min, and collect the supernatant;

[0136] (5) Purification: Purify the supernatant using an 8000-10000Da dialysis bag for 24-48 hours and collect the retentate;

[0137] (6) Extraction: The retentate was heated to 60-75°C, 75-90°C, and 90-95°C, respectively, with each heating time being 10-20 min, and ultrasonic treatment was performed at a power of 1000 W;

[0138] (7) Centrifugation: centrifuge the feed solution at 8000-10000 rpm for 10-30 min and collect the supernatant;

[0139] (8) Concentration: Concentrate the supernatant using a rotary evaporator at 50-60° C. for 1-2 h;

[0140] (9) Drying: The concentrated liquid is subjected to vacuum freeze drying at -40 to -60°C for 24 to 48 hours;

[0141] (10) Grinding: Grind the dried sample into 100-200 meshes to obtain refined tamarind polysaccharide.

[0142] The yield of tamarind polysaccharide of samples prepared by different extraction conditions can be seen in Table 2. It can be seen that increasing the temperature gradient and ultrasonic treatment can increase the yield of tamarind polysaccharide. When the heating temperature gradient is 60-75℃, 75-90℃, 90-95℃, each heating time is 10-20min, and ultrasonic treatment with a power of 1000W is used, the yield of tamarind polysaccharide of the prepared sample is significantly improved.

[0143] Table 2 Tamarind polysaccharide content of samples prepared under different extraction conditions

[0144]

[0145] Note: Different lowercase letters in the same column indicate significant differences between the corresponding data (P<0.05).

[0146] Comparative Example 1

[0147] A method for preparing tamarind polysaccharide, comprising the following steps:

[0148] Pretreatment → pulping → acid extraction → centrifugation → concentration → alcohol precipitation → drying → crushing

[0149] The specific steps are as follows:

[0150] (1) Pretreatment: washing, soaking, drying, shelling, crushing, and sieving the tamarind kernels to obtain tamarind kernel powder;

[0151] (2) pulping: adding 10-20 times the weight of water to the processed tamarind kernel powder for grinding to prepare tamarind kernel pulp;

[0152] (3) Acid extraction: Add 25-50 times the mass of 50% citric acid solution to the tamarind kernel slurry for extraction;

[0153] (4) Centrifugation: centrifuge the tamarind kernel slurry at 3000-5000 rpm for 10-30 min, and collect the supernatant;

[0154] (5) Concentration: Concentrate the liquid using a rotary evaporator at 50-60° C. for 1-2 h;

[0155] (6) Alcohol precipitation: add the same volume of ethanol to the concentrate for precipitation at a temperature of 2-8°C for 4-8 hours;

[0156] (7) Drying: The precipitate is freeze-dried in a vacuum at -40 to -60°C for 12 to 24 h;

[0157] (8) Crushing: crush the dried sample into 100-200 meshes to obtain tamarind polysaccharide.

[0158] Comparative Example 2

[0159] A method for preparing tamarind polysaccharide, comprising the following steps:

[0160] Pretreatment → pulping → water extraction → concentration → alcohol precipitation → drying → crushing

[0161] The specific steps are as follows:

[0162] (1) Pretreatment: washing, soaking, drying, shelling, crushing, and sieving the tamarind kernels to obtain tamarind kernel powder;

[0163] (2) pulping: adding 10-20 times the weight of water to the processed tamarind kernel powder for grinding to prepare tamarind kernel pulp;

[0164] (3) Water extraction: Heat the tamarind kernel slurry to 80-90°C and extract for 0.5-1h;

[0165] (4) Concentration: Concentrate the liquid using a rotary evaporator at 50-60° C. for 1-2 h;

[0166] (5) Alcohol precipitation: add the same volume of ethanol to the concentrate for precipitation at a temperature of 2-8°C for 4-8 hours;

[0167] (6) Drying: The precipitate is freeze-dried in a vacuum at -40 to -60°C for 12 to 24 hours;

[0168] (7) Crushing: crush the dried sample into 100-200 meshes to obtain tamarind polysaccharide.

[0169] Table 3 Comparison of the quality of tamarind polysaccharide samples prepared under different extraction conditions

[0170]

[0171] Note: Different lowercase letters in the same column indicate significant differences between the corresponding data (P<0.05).

[0172] The quality comparison of tamarind polysaccharide samples prepared by different extraction conditions can be seen in Table 3. It can be seen that the quality of tamarind polysaccharide samples prepared by biological fermentation method and tamarind polysaccharide samples prepared by traditional organic acid extraction method is relatively close. When further combined with graded water extraction and ultrasonic treatment, the yield of tamarind polysaccharide is significantly improved, and the sample appearance, solution appearance and viscosity are also better, and are significantly better than the tamarind polysaccharide samples prepared by traditional extraction methods. This is mainly because after lactic acid bacteria fermentation and separation process, the protein in the tamarind kernel slurry is effectively removed, thereby increasing the content of tamarind polysaccharide, thereby reducing the influence of aggregates formed by protein impurities in tamarind polysaccharide samples and solutions on the appearance. After multi-stage water extraction and ultrasonic treatment, the extraction efficiency of tamarind polysaccharide is further improved, and high-purity tamarind polysaccharide shows better uniformity, and the appearance of the product and solution is further improved. In addition, due to the removal of impurities such as protein, the interaction between tamarind polysaccharides is also enhanced, and the sample also shows higher viscosity. Therefore, when the biological fermentation method and the multi-stage water extraction method are combined with ultrasonic treatment to prepare tamarind polysaccharide, the lactic acid bacteria addition amount can be preferably 0.02-0.05%, the fermentation temperature is 40-42°C, the fermentation time is 8-12h, the heating temperature gradient is preferably 60-75°C, 75-90°C, 90-95°C, the heating time for each stage is 10-20min, and the ultrasonic power is 1000W, thereby preparing tamarind polysaccharide. The tamarind polysaccharide yield of the prepared sample is higher than that of the sample prepared by the traditional organic acid extraction method or the hot water extraction method, and the use of a large amount of organic reagents is avoided, which is beneficial to reducing the production cost. The appearance, solution transparency and viscosity of the prepared sample are improved. At the same time, the whole process is carried out by non-chemical means, realizing a green and clean production process.

[0173] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing tamarind polysaccharide, characterized in that: The following steps are involved: Pulping: Grind the tamarind kernel powder with water to make slurry; Fermentation: adding lactic acid bacteria to the tamarind kernel slurry for fermentation; Centrifugation: centrifuge the fermented tamarind kernel slurry and collect the supernatant; Purification: purify the supernatant and collect the retentate; Extraction: The retentate is heated to different temperatures for multi-stage extraction; Centrifugation: centrifuge the extracted liquid and collect the supernatant; Concentration: Concentrate the supernatant; Drying: The concentrated liquid is dried and crushed to obtain refined tamarind polysaccharide.

2. The method for preparing tamarind polysaccharide according to claim 1, characterized in that: The amount of water required for pulping is 10-20 times the mass of tamarind kernel powder.

3. The method for preparing tamarind polysaccharide according to claim 1, characterized in that: The addition amount of the lactic acid bacteria is 0.01-0.05% w / v, the fermentation temperature is 38-45° C., and the fermentation time is 4-12 hours.

4. The method for preparing tamarind polysaccharide according to claim 1 or 3, characterized in that: The lactic acid bacteria is Lactobacillus delbrueckii subsp. bulgaricus.

5. The method for preparing tamarind polysaccharide according to claim 1, characterized in that: After fermentation, the centrifugal speed is 3000-5000rpm and the time is 10-30min.

6. The method for preparing tamarind polysaccharide according to claim 1, characterized in that: Dialysis is used for purification, the dialysis time is 24-48 hours, and the molecular weight of the dialysis bag is 8000-10000Da.

7. The method for preparing tamarind polysaccharide according to claim 1, characterized in that: The multi-stage extraction heating process was 60-75°C, 75-90°C, and 90-95°C, with each stage lasting 10-20 min, combined with ultrasonic treatment.

8. The method for preparing tamarind polysaccharide according to claim 1, characterized in that: After multi-stage extraction, the centrifugal speed is 8000-10000 rpm and the time is 10-30 min.

9. The method for preparing tamarind polysaccharide according to claim 1, characterized in that: The temperature during the concentration process is 50-60°C and the time is 1-2h.

10. The method for preparing tamarind polysaccharide according to claim 1, characterized in that: The drying is vacuum freeze drying, the drying temperature is -40 to -60°C, and the drying time is 24 to 48 hours.

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