Preparation method and application of Chinese chestnut powder with low glycemic index

Abstract

The invention discloses a preparation method and application of Chinese chestnut powder with a low glycemic index, and belongs to the technical field of Chinese chestnut powder processing.The preparation method comprises the following steps that fresh raw Chinese chestnuts are subjected to shelling, dehulling and crushing treatment, and Chinese chestnut thick slurry precipitates are extracted through alkaline treatment; putting the chestnut thick slurry precipitate into a drying oven for drying treatment, and then grinding and screening to obtain chestnut starch; adding pure water into the obtained Chinese chestnut starch to prepare starch milk; adding lipase with a specific concentration into the starch milk in a coupling manner, and treating under a plasma micro-jet working condition to obtain Chinese chestnut starch milk; and performing ultrasonic treatment on the prepared Chinese chestnut starch milk, and then performing drying, grinding and screening treatment to obtain the finished product Chinese chestnut powder with the low glycemic index. The prepared Chinese chestnut powder has a low glycemic index, and meets the requirements of diabetic patients, obese people and people with special requirements.

Description

Technical Field

[0001] The invention relates to the technical field of chestnut powder processing, and in particular to a preparation method and application of low-glycemic index chestnut powder. Background Art

[0002] The glycemic index (GI) is an indicator used to express the extent to which food affects the rise in blood sugar. Foods with a low glycemic index mean that their carbohydrates will enter the blood at a slower rate, causing blood sugar levels to rise more slowly and steadily; it helps to maintain blood sugar stability and prevent diseases such as diabetes; it also helps to increase satiety, control weight and lose weight.

[0003] The shell of chestnut is hard and thorny. It is usually eaten after peeling the shell. It is rich in nutritional value. Chestnuts are usually eaten raw, fried, ground into flour, made into steamed buns, etc., and can also be used as a dish. The current problems with chestnut processing are: (1) Chestnuts contain a high content of carbohydrates, especially starch. Excessive consumption will increase the burden on the gastrointestinal tract; (2) For diabetic patients, excessive consumption of chestnuts may cause large fluctuations in blood sugar, which is not conducive to the control of the disease. Summary of the invention

[0004] Technical problems to be solved: In response to the technical problems existing in the use of chestnut powder in the background technology, the present invention provides a preparation method and application of low glycemic index chestnut powder. Chestnut powder with high resistant starch content and low glycemic index is beneficial to diabetic patients, obese people and people with special needs, avoiding rapid increase in blood sugar and fat accumulation caused by eating chestnut powder, and also helps to increase the application scope of chestnut powder and the proportion of its diversified audience.

[0005] Technical solution: The method for preparing a low glycemic index chestnut powder according to the present invention comprises the following steps: Step 1: shelling and peeling fresh raw chestnuts, crushing them, and extracting chestnut pulp precipitate by alkaline treatment; Step 2: placing the chestnut concentrated pulp precipitate in an oven for drying, and then grinding and screening to obtain chestnut starch; Step 3: Add the obtained chestnut starch into pure water to prepare starch milk; Step 4: adding lipase of a specific concentration into the starch milk, treating it under plasma microfluidics conditions, and obtaining chestnut starch milk; Step 5: The prepared chestnut starch milk is subjected to ultrasonic treatment, and then dried, ground and sifted to obtain finished chestnut powder with a low glycemic index.

[0006] Preferably, in step 1, 0.2% NaOH solution is added to the crushed slurry and the mixture is immersed for 12 hours.

[0007] Preferably, the chestnut pulp treated with alkali in step 1 is filtered, the filtrate is centrifuged at 4000 r / min for 5 min, the centrifugation is repeated twice, and the concentrated pulp obtained by centrifugation is merged into the chestnut concentrated pulp precipitate.

[0008] Preferably, in step 2, the chestnut concentrated pulp precipitate is centrifuged at a speed of 4000 r / min for 20 min, then dried in an oven at 45° C.; and then ground through an 80-mesh sieve to obtain chestnut starch.

[0009] Preferably, the mass fraction of the starch milk concentration in step 3 is 10%.

[0010] Preferably, the amount of the coupled lipase in step 4 is 0.2-0.6% of the mass of chestnut starch; the coupled lipase is Candida rugosa lipase CRL.

[0011] Preferably, in step 4, the jet power is 400-700w and the jet treatment time is 30-120s.

[0012] Preferably, in step 5, ultrasonic treatment is performed for 20 to 60 minutes at an ultrasonic power of 200 to 600 W and a temperature of 45° C.

[0013] Preferably, the starch slurry after ultrasonic treatment in step 5 is centrifuged at a speed of 4000 r / min for 5 min, and the centrifugation is repeated twice. The starch precipitate is dried in an oven at 45° C. for 12 h, and then ground through an 80-mesh sieve to obtain a finished chestnut powder.

[0014] The invention also discloses a low-glycemic index chestnut powder and application thereof as an auxiliary material in preparing food, medicine or health care product.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The chestnut powder with high resistant starch content and low glycemic index prepared by the present invention is beneficial to diabetic patients, obese people and people with special needs, avoiding rapid increase in blood sugar and fat accumulation caused by eating chestnut powder, and also helps to increase the application scope of chestnut powder and the proportion of its diversified audience; 2. The preparation method uses microfluidization coupled with lipase to modify chestnut powder, improve its digestibility and low glycemic index, slow down the glucose release rate of chestnut powder after human ingestion, and is suitable for consumption by diabetic patients, people who lose weight and people with special needs; 3. The preparation method utilizes coupled lipase to modify starch. Lipase can help decompose the fat or oil components in starch, thereby improving the purity or properties of starch. The addition of lipase may produce a synergistic effect with microfluidization and ultrasonic treatment to further promote the modification of starch. 4. Compared with the original chestnut starch, the chestnut powder prepared by the present invention may improve certain properties, such as solubility, stability, rheology, etc., thereby enhancing its application value in the fields of food, medicine, industry, etc.; and in some cases, it may also have more functionality, such as antioxidant, antibacterial, etc., to meet the needs of specific fields; the chestnut powder prepared by the present invention can also be used as an auxiliary material to be processed into other products to meet the needs of special groups of people. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the chestnut flour processing process according to an embodiment of the present invention; Figure 2 The figure is a bar graph showing the contents of fast-digestible starch, slow-digestible starch and resistant starch before and after the modification of the chestnut starch of the present invention; Figure 3 It is a line graph of the hydrolysis rate of chestnut starch before and after modification treatment of the present invention. DETAILED DESCRIPTION

[0017] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the following will be combined with the attached Figures 1 to 3 The technical solutions of the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0018] like Figure 1 As shown, a method for preparing low glycemic index chestnut powder of the present invention comprises the following steps: Step 1: shell and peel fresh raw chestnuts, crush them, add 0.2% NaOH solution to the crushed pulp, soak for 12 hours, and extract the chestnut concentrated pulp precipitate; Step 2: The chestnut pulp treated by the alkaline method is filtered, the filtrate is centrifuged at a speed of 4000r / min for 5min, the centrifugation is repeated twice, and the concentrated pulp obtained by the centrifugation is merged into the chestnut concentrated pulp precipitate; the chestnut concentrated pulp precipitate is centrifuged at a speed of 4000r / min for 20min, and then dried in an oven at 45°C; and then ground through an 80-mesh sieve to obtain chestnut starch; Step 3: adding the obtained chestnut starch to pure water to prepare a starch milk with a mass fraction of 10%; Step 4: adding lipase in an amount of 0.2-0.6% of the weight of chestnut starch to the starch milk, wherein the coupled lipase is Candida rugosa lipase CRL; treating the mixture under a plasma microjet condition with a power of 400-700 W for 30-120 s to obtain chestnut starch milk; Step 5: Ultrasonic treatment of the prepared chestnut starch milk at an ultrasonic power of 200-600w and a temperature of 45°C for 20-60min; the starch slurry after ultrasonic treatment is centrifuged at a speed of 4000r / min for 5min, and the cycle is centrifuged twice. The starch precipitate is dried in an oven at 45°C for 12h, and then ground through an 80-mesh sieve to obtain a finished chestnut powder with a low glycemic index.

[0019] The chestnut powder with high resistant starch content and low glycemic index prepared by the present invention is beneficial to diabetic patients, obese people and people with special needs, avoiding rapid increase in blood sugar and fat accumulation caused by eating chestnut powder, and also helps to increase the application scope of chestnut powder and the proportion of its diversified audience; the chestnut powder is modified by microjet coupling lipase to improve its digestibility resistance and low glycemic index, slow down the glucose release rate of chestnut powder after human body ingestion, and is suitable for consumption by diabetic patients, people who lose weight and people with special needs; starch is modified by coupling lipase, and lipase can help decompose fat or oil components in starch, thereby improving the purity or properties of starch; and the addition of lipase may produce a synergistic effect with microjet treatment and ultrasonic treatment, further promoting the modification of starch.

[0020] The present invention also discloses a low-glycemic index chestnut powder and its application as an auxiliary material in the preparation of food, medicine or health products. Compared with the original chestnut starch, the chestnut powder prepared by the present invention may improve certain properties, such as solubility, stability, rheology, etc., thereby enhancing its application value in the fields of food, medicine, industry, etc.; and in some cases, it may also have more functionality, such as anti-oxidation and antibacterial, etc., to meet the needs of specific fields; the chestnut powder prepared by the present invention can also be used as an auxiliary material to be processed into other products to meet the needs of special groups of people.

[0021] Example 1: Figure 1 As shown, a method for preparing low glycemic index chestnut powder of the present invention comprises the following steps: Step 1: Shell and peel fresh raw chestnuts and crush them, add 0.2% NaOH solution to the crushed pulp and soak for 12 hours to extract the chestnut concentrated pulp precipitate.

[0022] Step 2: The chestnut pulp treated by the alkali method is filtered, the filtrate is centrifuged at 4000r / min for 5min, the centrifugation is repeated twice, and the concentrated pulp obtained by the centrifugation is merged into the chestnut concentrated pulp precipitate; the chestnut concentrated pulp precipitate is centrifuged at 4000r / min for 20min, and then dried in an oven at 45°C; and then ground through an 80-mesh sieve to obtain chestnut starch.

[0023] Step 3: Add the obtained chestnut starch into pure water to prepare a starch milk with a mass fraction of 10%.

[0024] Step 4: adding lipase in an amount of 0.6% of the weight of chestnut starch to the starch milk, wherein the coupled lipase is Candida rugosa lipase CRL; treating for 60 seconds under a plasma microjet condition with a power of 600 W to obtain chestnut starch milk; Step 5: Ultrasonic treatment of the prepared chestnut starch milk at an ultrasonic power of 500w and a temperature of 45°C for 60min; the starch slurry after ultrasonic treatment is centrifuged at a speed of 4000r / min for 5min, and the cycle is centrifuged twice. The starch precipitate is dried in an oven at 45°C for 12h, and then ground through an 80-mesh sieve to obtain a finished chestnut powder with a low glycemic index.

[0025] The same batch of fresh raw chestnuts were selected to prepare chestnut powder using the preparation method of Example 1 and a conventional method, respectively. The glycemic index of the chestnut powder prepared by the method of Example 1 was 27, and the glycemic index of the chestnut powder prepared by the conventional method was 68.

[0026] Example 2: Figure 1 As shown, a method for preparing low glycemic index chestnut powder of the present invention comprises the following steps: Step 1: shell and peel fresh raw chestnuts, crush them, add 0.2% NaOH solution to the crushed pulp, soak for 12 hours, and extract the chestnut concentrated pulp precipitate; Step 2: The chestnut pulp treated by the alkali method is filtered, the filtrate is centrifuged at 4000r / min for 5min, the centrifugation is repeated twice, and the concentrated pulp obtained by the centrifugation is merged into the chestnut concentrated pulp precipitate; the chestnut concentrated pulp precipitate is centrifuged at 4000r / min for 20min, and then dried in an oven at 45°C; and then ground through an 80-mesh sieve to obtain chestnut starch.

[0027] Step 3: Add the obtained chestnut starch into pure water to prepare a starch milk with a mass fraction of 10%.

[0028] Step 4: 0.5% of the weight of chestnut starch lipase is coupled to the starch milk, wherein the coupled lipase is Candida rugosa lipase CRL; the mixture is treated for 60 seconds under a plasma microjet condition with a power of 700 W to obtain chestnut starch milk.

[0029] Step 5: Ultrasonicate the prepared chestnut starch milk at an ultrasonic power of 400w and a temperature of 45°C for 50min; centrifuge the starch slurry after ultrasonic treatment at a speed of 4000r / min for 5min, cycle the centrifugation twice, dry the starch precipitate in an oven at 45°C for 12h, and then grind through an 80-mesh sieve to obtain a finished chestnut powder with a low glycemic index.

[0030] The same batch of fresh raw chestnuts were selected to prepare chestnut powder using the method of Example 2 and the conventional method respectively. The glycemic index of the chestnut powder prepared by the method of Example 2 was 32, and the glycemic index of the chestnut powder prepared by the conventional method was 65.

[0031] Embodiment 3: A method for preparing low glycemic index chestnut flour according to the present invention, the preparation method comprising the following steps: Step 1: shell and peel fresh raw chestnuts, crush them, add 0.2% NaOH solution to the crushed pulp, soak for 12 hours, and extract the chestnut concentrated pulp precipitate; Step 2: The chestnut pulp treated by the alkaline method is filtered, the filtrate is centrifuged at a speed of 4000r / min for 5min, the centrifugation is repeated twice, and the concentrated pulp obtained by the centrifugation is merged into the chestnut concentrated pulp precipitate; the chestnut concentrated pulp precipitate is centrifuged at a speed of 4000r / min for 20min, and then dried in an oven at 45°C; and then ground through an 80-mesh sieve to obtain chestnut starch; Step 3: adding the obtained chestnut starch to pure water to prepare a starch milk with a mass fraction of 10%; Step 4: adding lipase in an amount of 0.4% of the weight of chestnut starch to the starch milk, wherein the coupled lipase is Candida rugosa lipase CRL; treating the mixture under a plasma microjet condition with a power of 500 W for 30 s to obtain chestnut starch milk; Step 5: Ultrasonic treatment of the prepared chestnut starch milk at an ultrasonic power of 300w and a temperature of 45°C for 40min; the starch slurry after ultrasonic treatment is centrifuged at a speed of 4000r / min for 5min, and the cycle is centrifuged twice. The starch precipitate is dried in an oven at 45°C for 12h, and then ground through an 80-mesh sieve to obtain a finished chestnut powder with a low glycemic index.

[0032] The same batch of fresh raw chestnuts were selected to prepare chestnut powder using the method of Example 3 and a conventional method respectively. The glycemic index of the chestnut powder prepared by the method of Example 3 was 30, and the glycemic index of the chestnut powder prepared by the conventional method was 60.

[0033] The chestnut powder products obtained in Examples 1 to 3 were subjected to fast digestion, slow digestion and resistant starch content determination and in vitro digestion simulation experiments. The experimental results are as follows: Figure 2, Figure 3 The chestnut flour prepared by the present invention has an increased content of resistant starch (RS), enhanced digestion resistance, and a reduced glycemic index in the experimental body.

[0034] Take an appropriate amount of chestnut powder sample prepared by the present invention, add sodium acetate solution for gelatinization, adjust the pH, add mixed enzyme solution and shake at 37°C for reaction, add anhydrous ethanol to kill the enzyme after completion, centrifuge and take the supernatant to determine the glucose content, and calculate the fast digestible, slow digestible and resistant starch contents of the sample according to the glucose content. Figure 2 As shown, the content of resistant starch (RS) in the modified chestnut flour is significantly higher than that in the gelatinized starch, indicating that the digestion resistance of the chestnut flour of the present invention is enhanced.

[0035] Take an appropriate amount of chestnut starch prepared by the present invention, conduct in vitro simulation experiments of the oral cavity, stomach and intestine, and calculate the in vitro hydrolysis rate of chestnut powder according to the glucose content, such as Figure 3 As shown. The hydrolysis index of chestnut powder can be obtained according to the hydrolysis rate, and the estimated glycemic index of chestnut powder can be calculated. Figure 3 This indicates that the chestnut flour of the present invention has the ability to reduce the glycemic index.

[0036] The above are preferred embodiments 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 principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing low glycemic index chestnut powder, characterized in that: The preparation method comprises the following steps: Step 1: shelling and peeling fresh raw chestnuts, crushing them, and extracting chestnut pulp precipitate by alkaline treatment; Step 2: placing the chestnut concentrated pulp precipitate in an oven for drying, and then grinding and sieving to obtain chestnut starch; Step 3: Add the obtained chestnut starch into pure water to prepare starch milk; Step 4: adding lipase of a specific concentration into the starch milk, treating it under plasma microfluidics conditions, and obtaining chestnut starch milk; Step 5: The obtained chestnut starch milk is subjected to ultrasonic treatment, and then dried, ground and sifted to obtain finished chestnut powder with a low glycemic index.

2. The method for preparing low glycemic index chestnut powder according to claim 1, characterized in that: In step 1, 0.2% NaOH solution is added to the crushed slurry and soaked for 12 hours.

3. The method for preparing low glycemic index chestnut powder according to claim 2, characterized in that: The chestnut pulp treated with the alkali method in step 1 is filtered, and the filtrate is centrifuged at a speed of 4000r / min for 5min, and the centrifugation is repeated twice, and the concentrated pulp obtained by centrifugation is merged into the chestnut concentrated pulp precipitate.

4. The method for preparing low glycemic index chestnut powder according to claim 1, characterized in that: In step 2, the chestnut concentrated pulp precipitate is centrifuged at a speed of 4000 r / min for 20 minutes, and then dried in an oven at 45° C.; and then ground through an 80-mesh sieve to obtain chestnut starch.

5. The method for preparing low glycemic index chestnut powder according to claim 1, characterized in that: The mass fraction of starch milk concentration in step 3 is 10%.

6. The method for preparing low glycemic index chestnut powder according to claim 1, characterized in that: In step 4, the amount of coupled lipase used is 0.2-0.6% of the weight of chestnut starch; the coupled lipase is Candida rugosa lipase CRL.

7. The method for preparing low glycemic index chestnut powder according to claim 1, characterized in that: In step 4, the jet power is 400~700w and the jet treatment time is 30~120s.

8. The preparation method and application of low glycemic index chestnut powder according to claim 1, characterized in that: Step 5: Ultrasonic treatment is performed at an ultrasonic power of 200-600 W and a temperature of 45° C. for 20-60 min.

9. The preparation method and application of low glycemic index chestnut powder according to claim 8, characterized in that: The starch slurry after ultrasonic treatment in step 5 is centrifuged at a speed of 4000 r / min for 5 minutes, and the cycle is centrifuged twice. The starch precipitate is dried in an oven at 45° C. for 12 hours, and then ground through an 80-mesh sieve to obtain the finished chestnut powder.

10. The low glycemic index chestnut powder prepared according to the preparation method according to any one of claims 1 to 9, and its use as an auxiliary material in the preparation of food, medicine or health care products.

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