阅读说明：本技术 一种魔芋葡苷聚糖的制备方法 (Preparation method of konjac glucomannan ) 是由 杨大伟 邓云辉 钟果林 张飞燕 李铁园 唐邦寿 田力华 于 2019-11-15 设计创作，主要内容包括：本发明属于食品加工技术领域,具体涉及一种魔芋葡苷聚糖的制备方法,包括S1清洗去皮,S2切片,S3灭酶,S4粉碎并研磨,S5制备魔芋葡苷聚糖溶液,S6离心和沉淀,S7酶解,S8离心、冷冻和干燥。本发明的目的是,提供一种魔芋葡苷聚糖的制备方法,以魔芋为原料,通过特定的加工方法,得到一种无化学添加,没有鱼腥气味,而且得到纯度和得率均很高的魔芋葡苷聚糖。(The invention belongs to the technical field of food processing, and particularly relates to a preparation method of konjac glucomannan, which comprises the steps of S1 cleaning and peeling, S2 slicing, S3 enzyme deactivation, S4 crushing and grinding, S5 preparation of konjac glucomannan solution, S6 centrifugation and precipitation, S7 enzymolysis, S8 centrifugation, freezing and drying. The invention aims to provide a preparation method of konjac glucomannan, which takes konjac as a raw material and obtains the konjac glucomannan which has no chemical addition, no fish smell and high purity and yield by a specific processing method.)

1. The preparation method of the konjac glucomannan is characterized by comprising the following steps:

s1, cleaning and peeling: cleaning fresh and non-rotten konjak bulbs, and removing the epidermis of the konjak bulbs during cleaning;

s2, slicing: slicing the cleaned konjak corm by a slicing machine, wherein the slicing thickness is 1-8 mm;

s3, enzyme deactivation: flatly paving the konjac slices in a microwave device in a single layer, and carrying out microwave irradiation treatment on the konjac slices for 60-100 seconds to inhibit the activity of polyphenol oxidase and prevent browning in the subsequent drying process;

s4, crushing and grinding: smashing and uniformly stirring the konjac pieces in the step S4, continuously spraying an acetic acid solution in the process, and grinding the uniformly stirred konjac to obtain ground konjac coarse powder;

s5, preparing a konjac glucomannan solution: dissolving the ground konjac flour in water, wherein the mass ratio of the water to the konjac coarse powder is 20-45:3-5, soaking for 4-6 hours at room temperature, stirring and washing for 20-60 minutes at the stirring speed of 100-200 revolutions per minute, and filtering to obtain filter residues;

s6, centrifugation and precipitation: adding acetic acid solution into the precipitate or filter residue, and stirring to obtain uniform colloidal solution; centrifuging the uniform colloidal solution, separating the supernatant from the precipitate, and collecting the precipitate respectively, wherein the precipitate is glucan and starch;

s7, enzymolysis: repeating S7 for many times, collecting the precipitate, adding acetic acid solution, stirring to obtain uniform colloidal solution, dissolving the collected precipitate with the colloidal solution for the last time, adding amylase to convert the starch into glucose, and fully stirring for enzymolysis, wherein the enzymolysis conditions are as follows: the enzymolysis temperature is 65-80 ℃, the enzymolysis pH is 5.0-6.0, and the enzymolysis time is 70-80 minutes;

s8, centrifugation, freezing and drying: centrifuging for 30 minutes after enzymolysis, separating and collecting the supernatant and the precipitate respectively; the precipitate is high-purity glucan, and the glucan powder is obtained after freeze drying.

2. The method of claim 1, wherein in S3, the konjac glucomannan is prepared by subjecting the konjac pieces of the core layer and the subcutaneous layer to microwave inactivation treatment with microwave equipment to inhibit polyphenol oxidase activity, respectively, wherein the microwave inactivation treatment of the konjac pieces of the core layer is performed by: laying the konjac pieces in a single layer, wherein each layer is at least one piece, the microwave power is 200-; the microwave enzyme deactivation mode of the konjac pieces of the core layer is as follows: the konjac pieces are laid in a single layer, each layer is at least one piece, and the microwave power is 500-.

3. The method for preparing konjac glucomannan according to claim 1, wherein after the enzyme deactivation in S3, drying: paving the konjac pieces in a microwave device in a single layer, drying the konjac pieces subjected to enzyme deactivation treatment by microwave irradiation, wherein the microwave power is 500-2000W, the drying time is 5-10 minutes, and the water content of the konjac pieces is not lower than 20%.

4. The method as claimed in claim 2, wherein the konjac glucomannan is obtained by grinding and milling the konjac pieces in S4 with 4-8 grinding wheel sets, wherein the grinding wheel sets are tight and loose to achieve a particle size of 100-180 meshes.

5. The method for producing konjac glucomannan according to any one of claims 1-2, wherein the amylase is α -amylase.

6. The method for preparing konjac glucomannan according to claim 1, wherein the pH during the enzymatic hydrolysis is adjusted with an acetic acid solution having a concentration of 0.2% to 0.3%.

7. The method for preparing konjac glucomannan according to claim 1, wherein the centrifugation condition in S6 is 800-.

8. The method for preparing konjac glucomannan according to claim 1, wherein the enzymolysis conditions in S7 are: the enzyme activity of the amylase is 400023U/g at 60-70 ℃, the addition amount is 15-20g of amylase added in every 100g of konjak precipitate, the enzymolysis temperature is 70-75 ℃, the enzymolysis pH is 5.5-6.0, and the enzymolysis time is 70-80 minutes.

Technical Field

The invention belongs to the technical field of food processing, and particularly relates to a preparation method of konjac glucomannan.

Background

Konjak, also called konjac and coprinus comatus, is a perennial herb of angiosperma, monocotyledons, Araceae, Thalictrum subfamily and Thalictrum tuberosum, and is the only economic plant for producing glucomannan. Konjak grows in sparse forests, is beneficial alkaline food, and can achieve balance of acid and alkali of food for people eating too many animal acidic foods by matching with konjak. Because of lack of biological enzyme for decomposing the glucan in the heat body, the glucan ingested by the human body can not provide heat, is healthy dietary fiber beneficial to losing weight, and has the effects of reducing blood fat, regulating endocrine, improving the gastrointestinal ecological environment and the like.

The industrial development of konjak in China starts late, the processing technology of purified konjak powder has no great breakthrough all the time, and particularly browning, gelatinization and adhesion are easily generated in the baking and dehydrating process to influence the product quality. At present, the konjak processing production in China is simple and rough, some simple processing factories are usually established on a konjak planting base, soil pit baking or mechanical drying is adopted, and the intensively harvested fresh konjak which is easy to damage and difficult to store is dried into dried konjak slices which are easy to store and transport, but the problems of blackening, browning and mildewing of the fresh konjak are all faced in the drying process, and the method for solving the blackening and browning of the konjak in the drying process is to fumigate the konjak with sulfur dioxide gas generated by burning sulfur in the drying process. The method for preventing konjac browning causes the product to contain a large amount of sulfur dioxide, and the content of the sulfur dioxide is more than 3 percent generally. Because the produced konjak contains sulfur dioxide, food pollution and hidden danger of food safety are caused. At present, the konjak is made into dry konjak pieces, the dry konjak pieces are made into fine konjak powder, and the fine konjak powder is purified and prepared into high-end product konjak micro powder in the konjak powder industry, so that the production process is complex, the production cost is high, the yield is low, and the product price is high. At present, extensive research is carried out to solve the technical and safety problems in the purification and use processes of the konjac flour.

At present, the materials are processed by a cyclone separation method in most markets. This production method has three disadvantages: (1) the yield of the glucan is lower, a large amount of the glucan is lost in the flying powder in the cyclone separation process, and the loss is larger and the yield is lower along with the improvement of the purity of the glucan. (2) Slight fishy smell appears due to the small amount of dimethylamine mixed in the glucan, affecting the mouthfeel. (3) The fly powder produced in the production process can not be well utilized, and the added value of the product is very low.

In order to solve a plurality of problems in the prior art, the invention provides a preparation method of konjac glucomannan.

Disclosure of Invention

In view of the above problems, the present invention provides a method for preparing konjac glucomannan, which uses konjac as a raw material and adopts a specific processing method to obtain konjac glucomannan which has no chemical additives, no fish smell and high purity and yield.

In order to realize the purpose, the invention adopts the technical scheme that:

a preparation method of konjac glucomannan comprises the following steps:

s1, cleaning and peeling: cleaning fresh and non-rotten konjak bulbs, and removing the epidermis of the konjak bulbs during cleaning;

s2, slicing: slicing the cleaned konjak corm by a slicing machine, wherein the slicing thickness is 1-8 mm;

s3, enzyme deactivation: flatly paving the konjac slices in a microwave device in a single layer, and carrying out microwave irradiation treatment on the konjac slices for 60-100 seconds to inhibit the activity of polyphenol oxidase and prevent browning in the subsequent drying process;

s4, crushing and grinding: smashing and uniformly stirring the konjac pieces in the step S4, continuously spraying an acetic acid solution in the process, and grinding the uniformly stirred konjac to obtain ground konjac coarse powder;

s5, preparing a konjac glucomannan solution: dissolving the ground konjac flour in water, wherein the mass ratio of the water to the konjac coarse powder is 20-45:3-5, soaking for 4-6 hours at room temperature, stirring and washing for 20-60 minutes at the stirring speed of 100-200 revolutions per minute, and filtering to obtain filter residues;

s6, centrifugation and precipitation: adding acetic acid solution into the precipitate or filter residue, and stirring to obtain uniform colloidal solution; centrifuging the uniform colloidal solution, separating the supernatant from the precipitate, and collecting the precipitate respectively, wherein the precipitate is glucan and starch;

s7, enzymolysis: repeating S7 for many times, collecting the precipitate, adding acetic acid solution, stirring to obtain uniform colloidal solution, dissolving the collected precipitate with the colloidal solution for the last time, adding amylase to convert the starch into glucose, and fully stirring for enzymolysis, wherein the enzymolysis conditions are as follows: the enzymolysis temperature is 65-80 ℃, the enzymolysis pH is 5.0-6.0, and the enzymolysis time is 70-80 minutes;

s8, centrifugation, freezing and drying: centrifuging for 30 minutes after enzymolysis, separating and collecting the supernatant and the precipitate respectively; the precipitate is high-purity glucan, and the glucan powder is obtained after freeze drying.

Further, in S3, microwave equipment is used to perform microwave enzyme deactivation treatment on the konjac pieces of the subcutaneous layer and the core layer respectively to inhibit polyphenol oxidase activity, and the microwave enzyme deactivation mode of the konjac pieces of the subcutaneous layer is as follows: laying the konjac pieces in a single layer, wherein each layer is at least one piece, the microwave power is 200-; the microwave enzyme deactivation mode of the konjac pieces of the core layer is as follows: the konjac pieces are laid in a single layer, each layer is at least one piece, and the microwave power is 500-.

Further, after the enzyme deactivation in S3, drying is performed: paving the konjac pieces in a microwave device in a single layer, drying the konjac pieces subjected to enzyme deactivation treatment by microwave irradiation, wherein the microwave power is 500-2000W, the drying time is 5-10 minutes, and the water content of the konjac pieces is not lower than 20%.

Further, the konjac pieces in the S4 are ground and ground by 4-8 grinding wheel sets, and the tightness of the grinding wheel sets is based on the fact that the granularity of the konjac is 100-180 meshes.

Further, the amylase is an alpha-amylase.

Further, the pH value in the enzymolysis is adjusted by using an acetic acid solution with the concentration of 0.2-0.3%.

Further, the centrifugation condition in S6 is 800-1500r/min, and the centrifugation time is 10-30 min.

Further, the enzymolysis conditions in the step S7 are as follows: the enzyme activity of the amylase is 400023U/g at 60-70 ℃, the addition amount is 15-20g of amylase added in every 100g of konjak precipitate, the enzymolysis temperature is 70-75 ℃, the enzymolysis pH is 5.5-6.0, and the enzymolysis time is 70-80 minutes.

The invention has the beneficial effects that:

1) the invention provides a processing method of konjac glucomannan, which ensures that the purity and the yield of the konjac glucomannan are high, no chemical additive is added, no fish smell exists, and the additional value of konjac is increased.

2) In the invention, microwave enzyme deactivation is respectively carried out on the subcutaneous layer and the core layer of the konjak to different degrees, so that the activity of polyphenol oxidase is thoroughly destroyed, partial burn or scorch of the konjak pieces is avoided, and the yield of konjak glucomannan is ensured to the maximum extent.

3) According to the invention, after the enzyme is inactivated in S2, drying treatment is carried out, so that uniform enzyme inactivation treatment on the konjac pieces is ensured, moisture in the material can be rapidly vaporized and migrated by the drying treatment, a micropore channel is formed, the grinding efficiency is ensured, non-enzymatic browning in the grinding process is inhibited, and the convenience for cleaning the grinding device after grinding is improved.

4) In the invention, microwave enzyme deactivation is carried out in S1, acetic acid solution is added in S4 and S6, and enzymolysis is carried out in S7, so that the activity of polyphenol oxidase is inhibited and eliminated, and browning is prevented; the product is dissolved in the solution and separated after the acetic acid solution reacts with the alkaloid, thereby eliminating the astringent taste of the konjac glucomannan; and after full enzymolysis in S7, centrifuging and precipitating for many times, reacting acetic acid solution with alkaloid, decomposing starch into monosaccharide dissolved in water, reducing the content of alkaloid and starch in konjac glucomannan, effectively improving the purity and yield of konjac glucomannan in konjac, and improving the quality of konjac glucomannan without introducing additional chemical substances.

Detailed Description

The present invention is described in detail below with reference to specific embodiments for better understanding of technical solutions of the present invention, and the description of the present invention is only exemplary and explanatory and should not be construed as limiting the scope of the present invention in any way.

A preparation method of konjac glucomannan comprises the following steps:

s1, cleaning and peeling: cleaning fresh and non-rotten konjak bulbs, and removing the epidermis of the konjak bulbs during cleaning;

s2, slicing: slicing the cleaned konjak corm by a slicing machine, wherein the slicing thickness is 1-8 mm;

s3, enzyme deactivation: flatly paving the konjac slices in a microwave device in a single layer, and carrying out microwave irradiation treatment on the konjac slices for 60-100 seconds to inhibit the activity of polyphenol oxidase and prevent browning in the subsequent drying process;

s4, crushing and grinding: smashing and uniformly stirring the konjac pieces in the step S4, continuously spraying an acetic acid solution in the process, and grinding the uniformly stirred konjac to obtain ground konjac coarse powder;

s5, preparing a konjac glucomannan solution: dissolving the ground konjac flour in water, wherein the mass ratio of the water to the konjac coarse powder is 20-45:3-5, soaking for 4-6 hours at room temperature, stirring and washing for 20-60 minutes at the stirring speed of 100-200 revolutions per minute, and filtering to obtain filter residues;

s6, centrifugation and precipitation: adding acetic acid solution into the precipitate or filter residue, and stirring to obtain uniform colloidal solution; centrifuging the uniform colloidal solution, separating the supernatant from the precipitate, and collecting the precipitate respectively, wherein the precipitate is glucan and starch;

s7, enzymolysis: repeating S7 for many times, collecting the precipitate, adding acetic acid solution, stirring to obtain uniform colloidal solution, dissolving the collected precipitate with the colloidal solution for the last time, adding amylase to convert the starch into glucose, and fully stirring for enzymolysis, wherein the enzymolysis conditions are as follows: the enzymolysis temperature is 65-80 ℃, the enzymolysis pH is 5.0-6.0, and the enzymolysis time is 70-80 minutes;

s8, centrifugation, freezing and drying: centrifuging for 30 minutes after enzymolysis, separating and collecting the supernatant and the precipitate respectively; the precipitate is high-purity glucan, and the glucan powder is obtained after freeze drying.

Preferably, in S3, microwave equipment is used to perform microwave enzyme deactivation treatment on the konjac pieces of the subcutaneous layer and the core layer respectively to inhibit polyphenol oxidase activity, and the microwave enzyme deactivation mode of the konjac pieces of the subcutaneous layer is as follows: laying the konjac pieces in a single layer, wherein each layer is at least one piece, the microwave power is 200-; the microwave enzyme deactivation mode of the konjac pieces of the core layer is as follows: the konjac pieces are laid in a single layer, each layer is at least one piece, and the microwave power is 500-.

Preferably, after the enzyme deactivation in S3, drying is performed: paving the konjac pieces in a microwave device in a single layer, drying the konjac pieces subjected to enzyme deactivation treatment by microwave irradiation, wherein the microwave power is 500-2000W, the drying time is 5-10 minutes, and the water content of the konjac pieces is not lower than 20%.

Preferably, the konjac pieces in the S4 are ground and ground by 4-8 grinding wheel sets, and the tightness of the grinding wheel sets is based on the fact that the granularity of the konjac is 100-180 meshes.

Preferably, the amylase is an alpha-amylase.

Preferably, the pH value in the enzymolysis is adjusted by using an acetic acid solution with the concentration of 0.2-0.3%.

Preferably, the centrifugation condition in S6 is 800-1500r/min, and the centrifugation time is 10-30 min.

Preferably, the enzymolysis conditions in the step S7 are as follows: the enzyme activity of the amylase is 400023U/g at 60-70 ℃, the addition amount is 15-20g of amylase added in every 100g of konjak precipitate, the enzymolysis temperature is 70-75 ℃, the enzymolysis pH is 5.5-6.0, and the enzymolysis time is 70-80 minutes.