Caramel Chinese chestnut powder and preparation method thereof

Abstract

The invention belongs to the technical field of food processing, and particularly relates to caramel Chinese chestnut powder and a preparation method thereof. The preparation method of the caramel Chinese chestnut powder provided by the invention comprises the following steps: 1) cooking Chinese chestnut pulp with water until the pulp does not have a hard core, so as to obtain cooked Chinese chestnuts; 2) cooling the cooked Chinese chestnuts, adding water, and pulping to obtain Chinese chestnut slurry; (3) carrying out enzymolysis on the Chinese chestnut pulp by using medium-temperature alpha-amylase, and then carrying out enzyme deactivation treatment; and 4) after the enzyme deactivation treatment is finished, concentrating the slurry after the enzyme deactivation into concentrated Chinese chestnut slurry, stir-frying the concentrated Chinese chestnut slurry at 120-130 DEG C to obtain a caramelized material, and then drying and crushing the caramelized material to obtain the caramelized Chinese chestnut powder. According to the preparation method of the caramel Chinese chestnut powder, the nutrition of Chinese chestnuts can be reserved, the digestion and absorption rate can be increased, natural and mellow scorched flavor can be formed, and harmful substances cannot be generated.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, and specifically relates to a caramel chestnut powder and its preparation method. Background Technology

[0002] Chestnuts are rich in starch, protein, dietary fiber, and various minerals, and are a traditional food and medicine ingredient. With the development of the food industry, the variety of processed chestnut products has increased. Among them, chestnut powder is widely used in baking, instant food, and baby food processing because it is convenient to eat and easy to store.

[0003] Current chestnut flour processing technologies mostly employ direct drying and grinding or simple steaming followed by powdering, which have the following drawbacks: First, chestnut starch has a dense structure, making it difficult for the human body to digest and absorb after direct powdering, especially unsuitable for the elderly, children, and those with weak digestive systems. Second, the product flavor is monotonous, mostly consisting of the mild taste of chestnuts themselves, lacking distinctiveness and failing to meet consumers' demands for diverse flavors. Third, some caramelization processes use high-temperature direct roasting, which easily leads to a burnt taste in the chestnut flour, significant loss of nutrients, and the generation of harmful substances. Furthermore, while directly adding powdered sugar during roasting can achieve a caramelized chestnut flavor, it may pose health risks.

[0004] Therefore, developing a caramel chestnut powder preparation technology that can both retain the nutrients of chestnuts and improve their digestibility and absorption rate, while also creating a naturally mellow and caramelized flavor, has become an urgent need in the current field of chestnut deep processing. Summary of the Invention

[0005] The purpose of this invention is to provide a caramel chestnut powder and its preparation method. This method preserves the nutrients of chestnuts, improves digestibility and absorption, and produces a naturally rich and mellow caramel flavor without generating harmful substances. It solves the problems of low digestibility, monotonous flavor, and easy burning during the caramelization process in existing chestnut powders, resulting in a nutritionally balanced and uniquely flavored caramel chestnut powder.

[0006] The first aspect of this invention provides a method for preparing caramel chestnut powder, comprising the following steps: 1) Steam the chestnut flesh in water until the flesh has no hard core, and you will get steamed chestnuts; 2) Cool the steamed chestnuts obtained in step 1), add water and blend into a paste to obtain chestnut paste; 3) The chestnut pulp obtained in step 2) was enzymatically hydrolyzed using medium-temperature α-amylase, and then the enzyme was inactivated. 4) After the enzyme inactivation treatment is completed, the enzyme-inactivated slurry is concentrated into chestnut concentrate. The concentrated slurry is stir-fried at 120-130℃ to obtain caramelized material. Then, the caramelized material is dried and crushed to obtain the caramelized chestnut powder.

[0007] In some embodiments, the drying temperature in step 4) is 40-60°C, and the caramel chestnut powder is dried until the moisture content is ≤6%. In some embodiments, the mass ratio of chestnut pulp to water in step 1) is 1:(1-1.5). And / or, the cooking pressure in step 1) is 0.1-0.12 MPa, and the cooking time is 20-30 min.

[0008] In some embodiments, step 1) involves steaming until the fruit pulp is soft and tender with no hard core.

[0009] In some embodiments, the chestnuts steamed in step 2) are cooled to 40-50°C; And / or, the mass ratio of water in step 2) to chestnut pulp in step 1) is (1-2):1; Optionally, after the water addition and pulping step is completed, a step of passing the pulp through a 100-120 mesh sieve is also included.

[0010] In some embodiments, the enzyme activity of the mesophilic α-amylase described in step 3) is 2000-3000 U / g; The amount of medium-temperature α-amylase added is 0.1%-0.3% of the chestnut pulp mass in step 1).

[0011] In some embodiments, the enzymatic hydrolysis temperature in step 3) is 60-70°C, the enzymatic hydrolysis time is 60-80 min, and the enzymatic hydrolysis stirring rate is 50-80 r / min; Before enzymatic hydrolysis as described in step 3), the pH of the chestnut pulp is adjusted to 6.0-7.0 with citric acid or sodium carbonate.

[0012] In some embodiments, the enzyme inactivation treatment temperature in step 3) is 95-100°C, and the enzyme inactivation treatment time is 10-15 min.

[0013] In some embodiments, the concentration vacuum degree in step 3) is 0.08-0.09 MPa and the concentration temperature is 65-75°C; The solids content of the chestnut concentrate is 60-70%.

[0014] The small molecule sugars produced by enzymatic hydrolysis after concentration in step 3) are fully enriched in the chestnut concentrate.

[0015] In some embodiments, the frying time in step 3) is 20-40 minutes; In some embodiments, after the crushing step described in step 3), a step of passing the material through a 100-120 mesh sieve is also included.

[0016] In some embodiments, the concentrated chestnut slurry is transferred to a double-helix stirring wok and stir-fried continuously at 120-130℃ for 20-40 minutes until the material is uniformly brown and has a distinct caramel flavor, and the moisture content of the chestnut powder is ≤6%, then heating is stopped. A second aspect of the present invention provides a caramel chestnut powder, which is prepared according to the above-described method for preparing caramel chestnut powder.

[0017] In some embodiments, the caramel chestnut powder has a moisture content of ≤6%, a starch hydrolysis degree of ≥25%, and a dietary fiber content of ≥2.5g per 100g of caramel chestnut powder.

[0018] In some embodiments, the acrylamide content in the caramel chestnut powder is less than 0.3 mg / kg.

[0019] In some embodiments, the caramel chestnut powder is uniformly brown and has a unique flavor that blends natural caramel aroma with the fresh aroma of chestnuts.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The method for preparing caramel chestnut powder provided by the present invention includes the following steps: 1) steaming chestnut flesh with water until the flesh has no hard core, to obtain steamed chestnuts; 2) cooling the steamed chestnuts obtained in step 1), adding water and pulping to obtain chestnut slurry; 3) enzymatically hydrolyzing the chestnut slurry obtained in step 2) using medium-temperature α-amylase, and then inactivating the enzyme; 4) after the enzyme inactivation treatment, concentrating the enzyme-inactivated slurry into chestnut concentrate, frying the chestnut concentrate at 120-130℃ to obtain caramelized material, and then drying and crushing the caramelized material to obtain the caramel chestnut powder. This invention utilizes medium-temperature α-amylase for enzymatic hydrolysis, significantly reducing the molecular weight of starch and forming small-molecule sugars that are easily digested by human enzymes. This solves the problem of poor digestibility and absorption of traditional chestnut powder, improving the digestibility and absorption rate of caramel chestnut powder. The enzymatically hydrolyzed chestnut pulp is then concentrated to enrich the small-molecule sugars, which are used as substrates for controlled caramelization. By controlling the temperature at 120-130℃ and the stir-frying time, the burnt flavor and harmful substances caused by direct high-temperature heating are avoided. The small-molecule sugars produced by enzymatic hydrolysis provide ample substrate for the caramelization reaction, promoting the synergistic effect of the Maillard reaction and caramelization, producing flavor compounds such as furans and pyrazines. This results in a unique flavor profile that blends a rich caramel aroma with the delicate fragrance of chestnuts, with the aroma component content increased by 2-3 times compared to traditional processes. The caramel chestnut powder provided by this invention retains the nutrients of chestnuts, improves digestibility and absorption, and produces a naturally rich caramel flavor without generating harmful substances. This invention addresses the problems of low digestibility and absorption rate, monotonous flavor, and easy burning during the caramelization process of existing chestnut flour, resulting in a caramelized chestnut flour with balanced nutrition and unique flavor.

[0021] 2. The method for preparing caramel chestnut powder provided by this invention, wherein the activity of the mesophilic α-amylase in step 3) is 2000-3000 U / g; the amount of mesophilic α-amylase added is 0.1%-0.3% of the chestnut pulp mass in step 1). The enzymatic hydrolysis temperature in step 3) is 60-70℃, the enzymatic hydrolysis time is 60-80 min, and the enzymatic hydrolysis stirring rate is 50-80 r / min; the pH of the chestnut slurry is adjusted to 6.0-7.0 with citric acid or sodium carbonate before enzymatic hydrolysis in step 3). This invention uses mesophilic α-amylase to perform targeted hydrolysis of chestnut starch. By optimizing the enzymatic hydrolysis temperature, pH value, and enzyme dosage, the degree of starch hydrolysis reaches more than 25%, further significantly reducing the molecular weight of starch and forming small molecule sugars that are easily digested by human digestive enzymes. This further solves the problem of poor digestibility and absorption of traditional chestnut powder, improves the digestibility and absorption rate of caramel chestnut powder, and is suitable for all types of people. 3. The method for preparing caramel chestnut powder provided by the present invention, wherein the cooking pressure in step 1) is 0.1-0.12 MPa and the cooking time is 20-30 min; the present invention adopts a vacuum cooking process, which avoids the destruction of vitamins, dietary fiber and other nutrients in chestnuts by high temperature, and at the same time the vacuum environment inhibits the occurrence of oxidation reaction, so that the caramel chestnut powder retains its complete nutrition and ensures the nutritional balance of the product; 4. The method for preparing caramel chestnut powder provided by the present invention, by clearly defining the range of values ​​for each process parameter, especially the precise control of enzymatic hydrolysis conditions and caramelization temperature, makes the production process stable and controllable, and the product quality uniform. It solves the problems of scorching and poor flavor that are easy to occur in traditional caramelization processes, and is suitable for large-scale industrial production.

[0022] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Detailed Implementation

[0023] Exemplary embodiments of the present invention will now be described in more detail. It should be understood that the present invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0024] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0025] In the description of the embodiments of this invention, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this invention, "multiple" means two or more, unless otherwise explicitly defined.

[0026] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0027] In the description of the embodiments of this invention, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0028] In the description of the embodiments of the present invention, the term "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more (including two groups), and "multiple pieces" refers to two or more (including two pieces).

[0029] In the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0030] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or through existing methods; unless otherwise specified, the amounts of experimental reagents used are the amounts used in conventional experimental operations; unless otherwise specified, the experimental methods are conventional methods. It should be further noted that the following descriptions are merely exemplary and not intended to limit the specific scope of the invention. Moreover, the comparative examples below are selected to compare with the technical solutions of the present invention to demonstrate the advancement of the present invention, and do not necessarily represent prior art in this technical field.

[0031] In the embodiments and comparative examples of this invention, the degree of starch hydrolysis was determined according to GB12099-89 "Determination of Reducing Power and Glucose Equivalent of Starch Hydrolyzed Products". The degree of starch hydrolysis = glucose equivalent / theoretical glucose content of complete starch hydrolysis. The theoretical glucose content of complete starch hydrolysis = starch mass * 1.111. Dietary fiber content was determined according to GB5009.88-2023 "National Food Safety Standard - Determination of Dietary Fiber in Food" for the determination of total dietary fiber content. Acrylamide content was determined according to GB5009.204-2025 "National Food Safety Standard - Determination of Acrylamide in Food" for gas chromatography-mass spectrometry.

[0032] Example 1 This embodiment provides a method for preparing caramel chestnut powder, including the following steps: 1) Select fresh chestnuts, manually remove the outer shell and inner skin, weigh 10kg of chestnut meat, rinse the chestnut meat with clean water 4 times, drain the water, then put it into a pressure cooker, add 12kg of purified water, and cook at 0.11MPa pressure for 30 minutes. After taking it out, check that the meat is soft and glutinous without a hard core to obtain the cooked chestnuts. 2) Cool the steamed chestnuts obtained in step 1) to 45°C, add 15kg of deionized water, grind them into a pulp using a colloid mill, and then pass the pulp through a 100-mesh sieve to obtain chestnut pulp. 3) Heat the chestnut pulp obtained in step 2) to 60℃, adjust the pH value to 6.0 with citric acid, add 30g of mesophilic α-amylase with an enzyme activity of 10000U / g, stir at a rate of 60r / min for 70min for enzymatic hydrolysis, and then heat to 98℃ and keep warm for 12min to inactivate the enzyme. 4) After enzyme inactivation, the enzyme-inactivated slurry is transferred to a vacuum concentrator and concentrated at a vacuum of 0.085 MPa and a temperature of 70°C until the solid content is 65%, yielding approximately 12.5 kg of chestnut concentrated slurry. The concentrated slurry is then transferred to a double-helix frying pan and stir-fried at 125°C for 25 minutes until the material is uniformly brown and emits a caramel aroma, thus obtaining caramelized material. The caramelized material is dried at 60°C until the moisture content is ≤6%, then crushed into powder and passed through a 100-mesh sieve to obtain approximately 9.8 kg of caramelized chestnut powder.

[0033] The caramel chestnut powder prepared in this embodiment is uniformly brown, with a starch hydrolysis degree of 31.6%, a dietary fiber content of 2.8g / 100g, and no acrylamide was detected. Sensory evaluation showed that it has a rich caramel aroma and a fresh chestnut fragrance, without any burnt taste, and has a delicate and smooth texture after mixing.

[0034] Example 2 This embodiment provides a method for preparing caramel chestnut powder, including the following steps: 1) Select fresh chestnuts, manually remove the outer shell and inner skin, weigh 5kg of chestnut meat, rinse the chestnut meat with clean water 3 times, drain the water, then put it into a pressure cooker, add 7.5kg of purified water, and cook at 0.1MPa pressure for 35 minutes. After taking it out, check that the meat is soft and glutinous without a hard core to obtain the cooked chestnuts. 2) Cool the steamed chestnuts obtained in step 1) to 40°C, add 6 kg of deionized water, grind them into a slurry using a colloid mill, and then pass the slurry through an 80-mesh sieve to obtain chestnut slurry. 3) Heat the chestnut pulp obtained in step 2) to 70℃, adjust the pH value to 6.0 with citric acid, add 15g of mesophilic α-amylase with an enzyme activity of 10000U / g, stir at a rate of 50r / min for 80min for enzymatic hydrolysis, and then heat to 95℃ and keep warm for 15min to inactivate the enzyme. 4) After enzyme inactivation, the enzyme-inactivated slurry is transferred to a vacuum concentrator and concentrated at a vacuum of 0.08 MPa and a temperature of 65°C until the solid content is 60%, yielding approximately 6.8 kg of chestnut concentrated slurry. The concentrated slurry is then transferred to a double-helix frying pan and stir-fried at 120°C for 32 minutes until the material is uniformly brown and emits a caramel aroma, thus obtaining caramelized material. The caramelized material is dried at 60°C until the moisture content is ≤6%, then crushed into powder and passed through a 100-mesh sieve to obtain approximately 4.7 kg of caramelized chestnut powder.

[0035] The caramel chestnut powder prepared in this embodiment is uniformly brown, with a starch hydrolysis degree of 36.5%, a dietary fiber content of 3.0g / 100g, and no acrylamide was detected. Sensory evaluation showed that it has a rich caramel flavor and can be directly brewed for drinking or used as a baking ingredient.

[0036] Comparative Example 1 This comparative example provides a method for preparing caramel chestnut powder, including the following steps: 1) Select fresh chestnuts, manually remove the outer shell and inner skin, weigh 5kg of chestnut meat, rinse the chestnut meat with clean water 3 times, drain the water, then put it into a pressure cooker, add 7.5kg of purified water, and cook at 0.1MPa pressure for 35 minutes. After taking it out, check that the meat is soft and glutinous without a hard core to obtain the cooked chestnuts. 2) Cool the steamed chestnuts obtained in step 1) to 40°C, add 6 kg of deionized water, grind them into a slurry using a colloid mill, and then pass the slurry through an 80-mesh sieve to obtain chestnut slurry. 3) Transfer the chestnut slurry obtained in step 2) into a vacuum concentrator and concentrate it to a solid content of 60% at a vacuum of 0.08 MPa and a temperature of 65°C to obtain chestnut concentrated slurry; transfer the concentrated slurry into a double spiral frying pan and stir-fry at 120°C for 32 minutes; dry the caramelized material at 60°C until the moisture content is ≤6%, then crush it into powder and pass it through a 100-mesh sieve to obtain 4.6 kg of caramelized chestnut powder.

[0037] The chestnut powder prepared in this comparative example had insufficient caramelization, resulting in a light color, a starch hydrolysis degree of only 3.2%, a dietary fiber content of 3.1 g / 100 g, and no acrylamide detected. Sensory evaluation showed that the taste was rough after reconstitution and lacked caramel flavor.

[0038] Comparative Example 2 This comparative example provides a method for preparing caramel chestnut powder, including the following steps: 1) Select fresh chestnuts, manually remove the outer shell and inner skin, weigh 5kg of chestnut meat, rinse the chestnut meat with clean water 3 times, drain the water, then put it into a pressure cooker, add 7.5kg of purified water, and cook at 0.1MPa pressure for 35 minutes. After taking it out, check that the meat is soft and glutinous without a hard core to obtain the cooked chestnuts. 2) Cool the steamed chestnuts obtained in step 1) to 40°C, add 6 kg of deionized water, grind them into a slurry using a colloid mill, and then pass the slurry through an 80-mesh sieve to obtain chestnut slurry. 3) Heat the chestnut pulp obtained in step 2) to 70℃, adjust the pH value to 6.0 with citric acid, add 15g of mesophilic α-amylase with an enzyme activity of 10000U / g, stir at a rate of 50r / min for 80min for enzymatic hydrolysis, and then heat to 95℃ and keep warm for 15min to inactivate the enzyme. 4) After enzyme inactivation, the enzyme-inactivated slurry is transferred to a vacuum concentrator and concentrated at a vacuum of 0.08 MPa and a temperature of 65°C until the solid content is 60%, yielding approximately 6.7 kg of chestnut concentrate. The concentrate is then transferred to a double-helix frying pan and stir-fried at 150°C for 32 minutes. The caramelized material is dried at 60°C until the moisture content is ≤6%, then crushed into powder and passed through a 100-mesh sieve to obtain approximately 4.6 kg of caramelized chestnut powder.

[0039] The chestnut powder prepared in this comparative example is light brown in color, which is darker than that in Example 1. The caramel chestnut powder has a starch hydrolysis degree of 30.9% and a dietary fiber content of 3.0 g / 100 g. It has a distinct burnt smell and fails the sensory evaluation. Furthermore, a small amount of acrylamide (content 0.3 mg / kg) was detected, while this substance was not detected in the product of Example 1 of this invention.

[0040] Comparative Example 3 This comparative example provides a method for preparing caramel chestnut powder, including the following steps: 1) Select fresh chestnuts, manually remove the outer shell and inner skin, weigh 5kg of chestnut meat, rinse the chestnut meat with clean water 3 times, drain the water, then put it into a pressure cooker, add 7.5kg of purified water, and cook at 0.1MPa pressure for 35 minutes. After taking it out, check that the meat is soft and glutinous without a hard core to obtain the cooked chestnuts. 2) Cool the steamed chestnuts obtained in step 1) to 40°C, add 6 kg of deionized water, grind them into a slurry using a colloid mill, and then pass the slurry through an 80-mesh sieve to obtain chestnut slurry. 3) Heat the chestnut pulp obtained in step 2) to 70℃, adjust the pH value to 6.0 with citric acid, add 15g of mesophilic α-amylase with an enzyme activity of 10000U / g, stir at a rate of 50r / min for 80min for enzymatic hydrolysis, and then heat to 95℃ and keep warm for 15min to inactivate the enzyme. 4) After enzyme inactivation, the enzyme-inactivated slurry is transferred to a vacuum concentration tank and concentrated to a solid content of 60% at a vacuum of 0.08 MPa and a temperature of 65°C. Then it is dried at 60°C until the moisture content is ≤6%, crushed into powder, and passed through a 100-mesh sieve to obtain caramel chestnut powder.

[0041] The caramel chestnut powder prepared in this comparative example has a slightly yellow color, a starch hydrolysis degree of 31.1%, a dietary fiber content of 3.1g / 100g, and does not contain acrylamide. According to sensory evaluation, it tastes sweet after mixing, but has no caramel aroma.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing caramel chestnut powder, characterized in that, Includes the following steps: 1) Steam the chestnut flesh in water until the flesh has no hard core, and you will get steamed chestnuts; 2) Cool the steamed chestnuts obtained in step 1), add water and blend into a paste to obtain chestnut paste; 3) The chestnut pulp obtained in step 2) was enzymatically hydrolyzed using medium-temperature α-amylase, and then the enzyme was inactivated. 4) After the enzyme inactivation treatment is completed, the enzyme-inactivated slurry is concentrated into chestnut concentrate slurry. The chestnut concentrate slurry is then stir-fried at 120-130℃ to obtain caramelized material. The caramelized material is then dried and crushed to obtain the caramelized chestnut powder.

2. The method for preparing caramel chestnut powder according to claim 1, characterized in that, The mass ratio of chestnut pulp to water in step 1) is 1:(1-1.5). And / or, the cooking pressure in step 1) is 0.1-0.12 MPa, and the cooking time is 20-30 min.

3. The method for preparing caramel chestnut powder according to claim 1 or 2, characterized in that, The chestnuts steamed in step 2) should be cooled to 40-50℃. And / or, the mass ratio of water in step 2) to chestnut pulp in step 1) is (1-2):1; Optionally, after the water addition and pulping step is completed, a step of passing the pulp through a 100-120 mesh sieve is also included.

4. The method for preparing caramel chestnut powder according to any one of claims 1-3, characterized in that, The enzyme activity of the mesophilic α-amylase described in step 3) is 2000-3000 U / g; The amount of medium-temperature α-amylase added is 0.1%-0.3% of the chestnut pulp mass in step 1).

5. The method for preparing caramel chestnut powder according to any one of claims 1-4, characterized in that, The enzymatic hydrolysis temperature in step 3) is 60-70℃, the enzymatic hydrolysis time is 60-80 min, and the enzymatic hydrolysis stirring rate is 50-80 r / min; Before enzymatic hydrolysis as described in step 3), the pH of the chestnut pulp is adjusted to 6.0-7.0 with citric acid or sodium carbonate.

6. The method for preparing caramel chestnut powder according to any one of claims 1-5, characterized in that, The enzyme inactivation treatment temperature in step 3) is 95-100℃, and the enzyme inactivation treatment time is 10-15 min.

7. The method for preparing caramel chestnut powder according to any one of claims 1-6, characterized in that, In step 3), the concentration vacuum degree is 0.08-0.09 MPa and the concentration temperature is 65-75℃. The solids content of the chestnut concentrate is 60-70%.

8. The method for preparing caramel chestnut powder according to any one of claims 1-6, characterized in that, The frying time mentioned in step 3) is 20-40 minutes; Optionally, after the crushing step described in step 3) is completed, a step of passing the material through a 100-120 mesh sieve may also be included.

9. A caramel chestnut powder, characterized in that, The caramel chestnut powder is prepared according to any one of claims 1-8.

10. The caramel chestnut powder according to claim 9, characterized in that, The caramel chestnut powder has a moisture content of ≤6%, a starch hydrolysis degree of ≥25%, and a dietary fiber content of ≥2.5g per 100g of caramel chestnut powder; And / or, the acrylamide content in the caramel chestnut powder is less than 0.3 mg / kg.