Special konjak flour as well as preparation method and application thereof

Abstract

The invention discloses special konjak flour as well as a preparation method and application thereof, and belongs to the technical field of food processing. The preparation method comprises the following steps: performing acidolysis on konjaku flour at 55-85 DEG C for 1-2 hours by adopting an inorganic acid solution, when the viscosity value of the konjaku flour is less than 100 mPa.s, adjusting the pH value of the solution to be neutral, and performing freeze drying to obtain the special konjaku flour, the konjaku flour is refined konjaku flour and / or coarse konjaku flour, and the addition amount is 50-80g / L. The special konjak flour obtained by the method can be used for preparing konjak dietary fiber supplement powder, konjak drinks or konjak jelly, is low in cost, controllable in product quality and capable of improving the added value of konjak, has various application values, has wide application prospects in the fields of food, medicine, chemical engineering and the like, and is suitable for industrial production. And technical support is provided for deep development and utilization of the konjak.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to special konjac flour and a preparation method and application thereof. Background Art

[0002] Konjac is a perennial herbaceous rhizome plant of the Araceae family. Konjac flour is a powder made from the tubers of konjac. Konjac flour is rich in glucomannan (KGM), a polysaccharide with a large molecular weight (usually between 200,000 and 2 million) that can form a viscous substance. The outer surface of KGM is wrapped with water molecules. When KGM is exposed to water, it absorbs a large amount of water, expands into elastic particles, and forms a layer of viscous substances. This viscous substance can combine with other ingredients to form a sticky substance, giving konjac flour a very high viscosity. In addition, because konjac flour particles are composed of very long and intertwined linear macromolecules, these macromolecules will form a complex network structure in water. At the same time, KGM can aggregate with water molecules through hydrogen bonds, molecular dipoles, induced dipoles, instantaneous dipoles and other forces into huge and difficult to move freely giant molecules, further increasing the viscosity of konjac flour.

[0003] Since konjac flour itself has extremely high viscosity, it increases the difficulty of handling konjac flour in food processing, such as stirring and mixing, and also reduces the stability of konjac derivatives, limiting their application areas. However, the existing konjac flour degradation process is complicated, and the viscosity of the obtained konjac flour still cannot meet the diverse needs of different fields. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the object of the present invention is to provide special konjac flour and its preparation method and application, so as to solve the technical problem that the existing konjac flour degradation process is complicated and the viscosity of konjac flour cannot meet the diversified needs of different fields.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention discloses a method for preparing konjac flour, comprising the steps of acid-hydrolyzing konjac flour at 55-85° C. for 1-2 hours using an inorganic acid solution, and adjusting the pH of the solution to neutral when the viscosity of the konjac flour is less than 100 mPa·s, and freeze-drying the solution to obtain the konjac flour.

[0007] Wherein, the addition amount of konjac flour is 50-80g / L.

[0008] Preferably, the inorganic acid solution is hydrochloric acid, acetic acid, phosphoric acid or tartaric acid solution.

[0009] Preferably, the concentration of the inorganic acid solution is 0.1 mol / L to 0.3 mol / L.

[0010] Preferably, the konjac flour is konjac refined flour and / or konjac coarse flour.

[0011] More preferably, the particles of konjac flour with a particle size of 0.125 to 0.425 mm account for more than 90%, and the particles of konjac flour with a particle size of ≤0.425 mm account for more than 90%.

[0012] The second aspect of the present invention discloses special konjac flour obtained by the above preparation method.

[0013] The third aspect of the present invention discloses the use of the above-mentioned konjac flour in preparing jelly, beverage or dietary fiber supplement food.

[0014] The fourth aspect of the present invention discloses konjac dietary fiber supplement powder, including konjac special powder. The preparation method of the konjac special powder is as follows: 0.1 mol / L hydrochloric acid solution is mixed with konjac flour at 85°C, acid hydrolyzed for 2 hours, and when the viscosity of the konjac flour is less than 100 mPa·s, the pH value is adjusted to 7.0 to obtain the konjac special powder; wherein the addition amount of the konjac flour is 50 g / L, and the konjac flour is konjac refined flour or konjac coarse flour.

[0015] A fifth aspect of the present invention provides a konjac drink comprising konjac flour. The preparation method of the konjac flour is as follows: mixing a 0.3 mol / L hydrochloric acid solution with konjac flour at 85° C., acid hydrolyzing for 2 hours, and when the viscosity of the konjac flour is less than 100 mPa·s, adjusting the pH value to 7.0 to obtain the konjac flour; wherein the amount of konjac flour added is 50 g / L.

[0016] A sixth aspect of the present invention provides konjac jelly, comprising konjac flour. The preparation method of the konjac flour is as follows: mixing 0.1 mol / L hydrochloric acid solution with konjac flour at 55° C., acid hydrolyzing for 1 hour, and when the viscosity of the konjac flour is less than 100 mPa·s, adjusting the pH value to 7.0 to obtain the konjac flour; wherein the amount of konjac flour added is 50 g / L.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The preparation method of konjac flour provided by the present invention comprises the following steps: 1) acid hydrolyzing konjac flour by adding inorganic acid solution, which has low degradation cost. By placing KGM in konjac flour in acidic conditions, glycosidic bond cleavage is induced, and polysaccharide fragments with smaller relative molecular mass are produced, thereby achieving the purpose of degradation; in addition, inorganic acid has higher degradation efficiency than organic acid, and the relative molecular mass of degradation products is smaller and the degree of polymerization is lower. 2) The added concentration of konjac flour is 50-80 g / L, which can ensure that the viscosity of the prepared konjac flour is maintained in the range of 50-100 mPa·s, and the performance stability, processing performance and taste of konjac derivatives are ensured. 3) The acid hydrolysis temperature is maintained at 55-85° C., and the acid hydrolysis time is maintained at 1-2 hours, which can ensure that the viscosity value of the konjac flour is maintained at the most stable level. Therefore, the method is simple and easy to implement through acid hydrolysis transformation, has low cost, is suitable for large-scale industrial production, can realize the controllable degradation of KGM, and the prepared konjac special flour has stable performance and reliable quality, can be used for preparing konjac dietary fiber supplement powder, konjac beverage or konjac jelly, better meets the diversified needs of different fields, and has good economic and social benefits.

[0019] The konjac dietary fiber supplement powder provided by the invention is prepared from special konjac flour, and can ensure that the prepared taro dietary fiber supplement powder is rich in dietary fiber, can be used as a nutritional supplement, and is helpful to improve intestinal function and increase satiety.

[0020] The konjac drink provided by the invention is prepared from special konjac flour, and can ensure that the obtained drink has good taste and certain health care functions.

[0021] The konjac jelly provided by the invention is prepared from special konjac flour, and can ensure that the obtained konjac jelly has good taste and color. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Be the testing result figure of the viscosity value of the special konjak powder that embodiment 1 makes and the special konjak meal viscosity value that embodiment 2 makes under different acidolysis temperatures;

[0023] Figure 2 Be the testing result figure of the viscosity value of the special konjak powder that embodiment 1 makes and the special konjak meal viscosity value that embodiment 2 makes under different acidolysis times;

[0024] Figure 3 Be the testing result figure of the viscosity value of the special konjak powder that embodiment 1 makes and the special konjak meal viscosity value that embodiment 2 makes under different acid concentrations;

[0025] Figure 4 Be the testing result figure of the viscosity value of the special konjak powder that embodiment 1 makes and the special konjak meal that embodiment 2 makes under different konjak flour additions;

[0026] Figure 5 The TCL analysis results of the konjac powder prepared in Example 1 and the konjac powder prepared in Example 2 at different acid hydrolysis temperatures are shown in Figure 1; wherein A: konjac powder; B: konjac powder; a: undegraded konjac flour; b: glucose; cg represents the acid hydrolysis temperatures of 55, 65, 75, 85, and 95° C., respectively;

[0027] Figure 6 The TCL analysis results of the konjac powder prepared in Example 1 and the konjac powder prepared in Example 2 at different acid hydrolysis times are shown in FIG. 1 ; wherein A: konjac powder; B: konjac powder; a: undegraded konjac flour; b: glucose; cg represents the acid hydrolysis time of 1, 1.5, 2, 2.5, and 3 h, respectively;

[0028] Figure 7 The figures are TCL analysis results of the konjac powder prepared in Example 1 and the konjac powder prepared in Example 2 under different acid concentrations; wherein, A: konjac powder; B: konjac powder; a: undegraded konjac flour; b: glucose; cg represents the concentration of added hydrochloric acid of 0.1, 0.2, 0.3, 0.4, 0.5 mol / L respectively;

[0029] Figure 8 It is a TCL analysis result diagram of the special konjac powder prepared in Example 1 and the special konjac coarse powder prepared in Example 2 under different konjac powder addition amounts; wherein, A: special konjac coarse powder; B: special konjac powder; a: undegraded konjac powder; b: glucose; cg represents that the concentration of added konjac powder is 30, 40, 50, 60, 80 mol / L respectively. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0031] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0032] Herein, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0033] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0034] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0035] The invention provides a method for preparing special konjak flour, comprising the following steps:

[0036] 1, raw material preparation: get konjac flour, described konjac flour is one or both in konjac powder (particles with a particle size of 0.125~0.425mm (120 mesh~40 mesh) account for more than 90%) and konjac meal (particles with a particle size≤0.425mm (40 mesh) account for more than 90%);

[0037] 2. Prepare acid solution: prepare 0.1-0.3 mol / L acid solution for standby use;

[0038] The acid solution is an inorganic acid solution, and the inorganic acid solution is hydrochloric acid, acetic acid, phosphoric acid or tartaric acid solution;

[0039] 3. Acidolysis treatment: the acid solution of 0.1~0.3mol / L prepared in step 2 is put into 55~85 ℃ of water-baths and preheated, then the konjac flour prepared in step 1 is joined in the preheated acid solution, the addition of konjac flour is 50~80g / L, and the konjac flour is fully swollen under stirring, after sealing with plastic wrap, 55~85 ℃ of heating in water bath for 2h is carried out acidolysis.

[0040] 4. Post-treatment: After the acid hydrolysis is completed, the sample is cooled to room temperature, and the viscosity is measured by a rotational viscometer. A suitable rotor is selected, and the machine is kept horizontal. After stabilization, the viscosity value is read and recorded. When the viscosity value is less than 100 mPa·s, the pH value is adjusted to 7.0 with sodium hydroxide, and the sample is frozen on a flat plate, and finally freeze-dried to obtain konjac flour.

[0041] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0042] The following examples use conventional instruments and equipment in this area. The experimental methods in the following examples that do not specify specific conditions are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. The konjac flour and konjac meal used in the following examples are purchased from Hubei Yizhi Konjac Biotechnology Co., Ltd.; other various raw materials, unless otherwise specified, all use conventional commercial products, and their specifications are conventional specifications in this area.

[0043] 1. Preparation of konjac flour

[0044] Embodiment 1: for preparing the konjac special refined flour of konjac dietary fiber supplement powder

[0045] (1) Get a certain amount of konjac flour, standby;

[0046] (2) Prepare 50 mL of 0.1 mol / L hydrochloric acid solution and preheat it in a water bath at 85°C;

[0047] (3) Add 2.5 g of konjac flour to the preheated hydrochloric acid solution at an addition amount of 50 g / L, fully swell under stirring, seal with plastic wrap, and heat in a water bath at 85° C. for 2 h;

[0048] (4) After the acid hydrolysis is completed, cool to room temperature and measure the viscosity with a rotational viscometer. Select a suitable rotor and ensure that the machine is level. After the value stabilizes, read and record the viscosity value;

[0049] (5) When the viscosity of the konjac flour is less than 100 mPa·s, the pH value is adjusted to 7.0 with sodium hydroxide, the flour is frozen in a flat plate, and the flour is placed in a freeze dryer to obtain konjac flour.

[0050] The konjac special refined flour prepared by the method can be used to prepare konjac dietary fiber supplement powder, and the added mass percentage is 0.5% to 5%.

[0051] Embodiment 2: for preparing the konjac special coarse powder of konjac dietary fiber supplement powder

[0052] (1) select appropriate konjac meal, standby;

[0053] (2) Prepare 50 mL of 0.1 mol / L hydrochloric acid solution and preheat it in a water bath at 85°C;

[0054] (3) Add 2.5 g of konjac flour to the preheated hydrochloric acid solution at an addition amount of 50 g / L, fully swell under stirring, seal with plastic wrap, and heat in a water bath at 85° C. for 2 h;

[0055] (4) After the acid hydrolysis is completed, cool to room temperature and measure the viscosity with a rotational viscometer. Select a suitable rotor and ensure that the machine is level. After the value stabilizes, read and record the viscosity value;

[0056] (5) When the viscosity of the konjac flour is less than 100 mPa·s, the pH value is adjusted to 7.0 with sodium hydroxide, the flour is frozen in a flat plate, and the flour is dried in a freeze dryer to obtain a coarse flour for konjac.

[0057] The special konjac coarse flour prepared by the method can be used to prepare konjac dietary fiber supplement powder, and the added mass percentage is 0.5% to 5%.

[0058] Embodiment 3: for preparing konjac beverage special konjac beverage powder

[0059] (1) select appropriate konjac meal, standby;

[0060] (2) Prepare 50 mL of 0.3 mol / L hydrochloric acid solution and preheat it in a water bath at 85°C;

[0061] (3) Add 2.5 g of konjac flour to the preheated hydrochloric acid solution at an addition amount of 50 g / L, fully swell under stirring, seal with plastic wrap, and heat in a water bath at 85° C. for 2 h;

[0062] (4) After the acid hydrolysis is completed, cool to room temperature and measure the viscosity with a rotational viscometer. Select a suitable rotor and ensure that the machine is level. After the value stabilizes, read and record the viscosity value;

[0063] (5) When the viscosity of the konjac flour is less than 100 mPa·s, the pH value is adjusted to 7.0 with sodium hydroxide, the flour is frozen in a flat plate, and the flour is dried in a freeze dryer to obtain a konjac beverage powder.

[0064] The konjac beverage powder prepared by the method can be used to prepare konjac beverages, and the added mass percentage is 0.5% to 5%.

[0065] Embodiment 4: for preparing konjac jelly special jelly powder of konjac

[0066] (1) Get a certain amount of konjac flour, standby;

[0067] (2) Prepare 50 mL of 0.1 mol / L hydrochloric acid solution and preheat it in a 55°C water bath;

[0068] (3) Add 4 g of konjac flour to the preheated hydrochloric acid solution at an addition amount of 80 g / L, fully swell under stirring, seal with plastic wrap, and heat in a 55° C. water bath for 1 h;

[0069] (4) After the acid hydrolysis is completed, cool to room temperature and measure the viscosity with a rotational viscometer. Select a suitable rotor and ensure that the machine is level. After the value stabilizes, read and record the viscosity value;

[0070] (5) When the viscosity of the konjac flour is less than 100 mPa·s, the pH value is adjusted to 7.0 with sodium hydroxide, the flour is frozen in a flat plate, and the flour is placed in a freeze dryer to obtain a jelly powder for konjac.

[0071] The special konjac jelly powder prepared by the method can be used to prepare konjac jelly, and the ratio of the special konjac powder to water is 1: (30-50).

[0072] 2. Detection of konjac flour

[0073] 1, the detection of viscosity value: among embodiment 1~embodiment 4, the viscosity value testing result of each group konjaku special flour is as follows Figure 1 to Figure 4 As shown, it can be seen that:

[0074] For Example 1, Figure 1 It can be seen that at 85°C, the viscosity of konjac flour decreased significantly compared with other temperatures, indicating that acid hydrolysis at this temperature has a significant degradation effect on konjac flour, reducing its viscosity, which meets the viscosity requirements for preparing konjac dietary fiber supplement powder and helps to improve the processing performance and taste of the product; Figure 2 It can be seen that within 1 to 3 hours of acid hydrolysis, the viscosity of konjac flour gradually decreased, with the fastest decrease in 1 to 1.5 hours, and stabilized after 2 hours, indicating that 2 hours is the best acid hydrolysis time; Figure 3 It can be seen that the viscosity of konjac flour is in an appropriate range at an acid concentration of 0.2 mol / L, indicating that this acid concentration can effectively control the degradation degree of konjac flour, ensure the stability of product performance, and meet the requirements of dietary fiber supplement powder. Figure 4 It can be seen that the viscosity of konjac flour increases with the increase of konjac flour concentration. When the sugar concentration is between 50 and 80 g / L, the viscosity of konjac flour increases fastest.

[0075] For Example 2, from Figure 1 It can be seen that the viscosity of konjac flour decreased significantly at 85°C, indicating that this temperature has a significant degradation effect on konjac flour and can effectively improve its processing performance. Figure 2 It can be seen that within 1 to 3 hours of acid hydrolysis, the viscosity of konjac flour gradually decreased, with the fastest decrease in 1 to 1.5 hours, and stabilized after 2 hours, indicating that 2 hours is the best acid hydrolysis time; Figure 3 It can be seen that the viscosity of the konjac powder is in an appropriate range under the acid concentration of 0.1 mol / L, indicating that this acid concentration can effectively control the degradation degree of the konjac powder. Figure 4 It can be seen that the addition of 50 g / L konjac flour keeps the viscosity in an appropriate range during the acid hydrolysis process, ensuring stable product quality and meeting the preparation requirements of konjac dietary fiber supplement powder.

[0076] For Example 3, it was found from the test results that, under the conditions of 85°C and 0.3mol / L, the viscosity of the konjac special beverage powder was greatly reduced to a range suitable for konjac beverages, so that the product had good fluidity and mouthfeel, and met the requirements of konjac beverages for raw material viscosity; its viscosity was lowest when the acid hydrolysis time was 2h, and it tended to be stable after 2h; in addition, the addition of 50g / L of konjac coarse flour made the viscosity in a suitable range during the acid hydrolysis process, ensuring stable product quality.

[0077] For embodiment 4, it is found by testing result that when 55 DEG C, the viscosity of jelly powder for konjak decreases compared to konjak powder, which shows that the degradation effect of acidolysis on konjak powder at this temperature is remarkable, and its viscosity is reduced, but it meets the requirement of preparing konjak jelly to viscosity, and it is helpful to improve the processing performance and mouthfeel of product; In acidolysis 1~3h, its viscosity gradually decreases, and 1~1.5h decreases the most rapidly, and tends to be stable after 2h, but viscosity is relatively low, does not meet the requirement of konjak jelly to viscosity, and illustrates that 1h is the best acidolysis time; Under 0.1mol / L acid concentration, the viscosity of jelly powder for konjak is in suitable range, and it is illustrated that this acid concentration can effectively control the degradation degree of konjak powder, ensures that product performance is stable, and meets the characteristic demand as konjak jelly. The viscosity of jelly powder for konjak is on the rise along with the increase of konjak powder concentration, and sugar concentration is higher in viscosity when 80g / L, and product performance is stable and nutritious.

[0078] 2, total soluble sugar content is measured: the konjac special flour obtained by embodiment 1~embodiment 4 is respectively prepared as 2mg / mL sample solution. The soluble sugar content in the sample is measured by phenol-sulfuric acid method, and the concentration of glucose (Glc) standard solution is 0.2mg / mL. Take 0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0mL Glc standard solution in a test tube respectively, and add distilled water to 2.0mL. Add 50 μL of phenol solution with a concentration of 80%, then add 2.5mL of concentrated sulfuric acid, leave standstill for 10min, leave standstill for 20min after vigorous vibration, and measure the absorbance of sample at 490nm. According to the quality and absorbance of Glc, draw a standard curve. Draw 50 μL of sample to be tested, measure according to the above method, and calculate the soluble sugar content of sample according to the standard curve.

[0079] Table 1 Soluble sugar content of konjac flour at different acid hydrolysis temperatures

[0080]

[0081] Table 2 Soluble sugar content of konjac flour at different acid hydrolysis times

[0082]

[0083] Table 3 Soluble sugar content of konjac flour at different acid concentrations

[0084]

[0085]

[0086] Table 4 Soluble sugar content of konjac flour at different konjac flour addition amounts

[0087]

[0088] The test results of Example 1 and Example 2 are shown in Table 1 to Table 4. For Example 1, it can be seen from Table 1 that at 75 to 95°C, the soluble sugar content of the konjac special powder is at a certain level, indicating that acid hydrolysis at this temperature can achieve a certain degree of degradation, and can ensure that an appropriate amount of nutrients are retained, which is beneficial to the function of the dietary fiber supplement powder. As shown in Table 2, when the acid hydrolysis time is 2h and 3h, the sugar content of the konjac special powder is maintained at an optimal level. As shown in Table 3, under 0.1mol / L acid concentration, the soluble sugar content meets expectations, further proving that the acid concentration can better balance the degradation effect and nutritional retention when degrading konjac powder. As shown in Table 4, when the addition amount of konjac flour is 80g / L, the soluble sugar content is reasonable, further proving that this scheme can prepare a konjac dietary fiber supplement powder with stable performance and suitable nutrition by controlling conditions. For Example 2, as shown in Table 1, the soluble sugar content of the konjac special meal at 65°C to 85°C meets the nutritional requirements of the dietary fiber supplement powder, indicating that the acid hydrolysis conditions at this temperature can both achieve effective degradation of the konjac meal and retain necessary nutrients. As shown in Table 4, the soluble sugar content is reasonable when the addition amount is 50 to 60g / L, further proving that this scheme can prepare a konjac dietary fiber supplement powder with stable performance and suitable nutrition by controlling the conditions.

[0089] For Example 3, the test results show that, at 85 ° C and 0.3 mol / L, the soluble sugar content of the konjac special drink powder is at an appropriate level, which can ensure that the konjac drink has certain nutrients, and can improve its processing performance by degradation, indicating that this solution can effectively control the degradation degree of konjac meal, and prepare a special powder that meets the needs of konjac drink. For Example 4, at 55 ° C, the soluble sugar content of the konjac special jelly powder is at a certain level, indicating that acid hydrolysis at this temperature can achieve a certain degree of degradation, and can ensure that an appropriate amount of nutrients are retained, which is beneficial to the function of konjac jelly. The soluble sugar content is in line with expectations under 0.1 mol / L acid concentration, which further proves that the acid concentration can better balance the degradation effect when degrading konjac powder, so that the performance is stable.

[0090] 3, thin layer chromatography (TLC): get konjac flour addition, hydrochloric acid addition, acidolysis temperature, acidolysis time and be 8 μ L to be measured of the konjac special powder that influence factor makes, take Glc, the konjac flour (2mg / mL) of not acidolysis as standard control, carry out 1h separation analysis on thin layer plate, after separation is completed, spray chromogen, thin layer plate is carried out heating color development, until band color development is complete.Developing agent: n-butyl alcohol: glacial acetic acid: water=4:7:1.

[0091] The color development results of Example 1 and Example 2 are as follows Figures 5 to 8 As shown, for Example 1, from Figure 5 and Figure 7 TLC analysis shows that at 85°C and 0.1 mol / L, the polysaccharides in the konjac flour are degraded, and the richness of the contained sugars is significantly improved, producing a sugar composition suitable for dietary fiber supplement powder, indicating that this solution can accurately control the degradation process of konjac flour, prepare products that meet specific needs, and make up for the lack of specificity in the existing konjac flour preparation. Figure 5 and Figure 8 TLC analysis showed that under the conditions of 85°C and 50g / L, the polysaccharides in the konjac flour were degraded, and the sugar richness of the konjac flour was significantly increased after the acid hydrolysis temperature reached 85°C. The changes in sugars in the konjac flour met the requirements of dietary fiber supplement powder, indicating that this scheme can accurately regulate the degradation process of konjac flour and prepare highly targeted products to meet the market demand for konjac dietary fiber supplement powder.

[0092] For Example 3, it was found from the test results that under the conditions of 85°C and 0.3mol / L, the polysaccharides in the konjac meal were degraded, and the sugar richness of the konjac meal was significantly improved after the acid hydrolysis temperature was 85°C, and the sugar changes in the konjac meal met the requirements of the konjac beverage, indicating that this solution can accurately achieve the controllable degradation of the konjac meal, prepare a special powder that meets the requirements of the konjac beverage production, and improve the application value of konjac in the beverage field, and improve the defects of the prior art. For Example 4, it was found from the test results that under the conditions of 55°C and 0.1mol / L, the polysaccharides in the konjac powder were degraded, indicating that this solution can accurately control the degradation process of the konjac powder, prepare a product that meets specific needs, and make up for the lack of targetedness in the existing konjac special powder preparation.

[0093] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. The preparation method of konjak flour is characterized in that, Acid hydrolyze konjac flour at 55-85° C. for 1-2 hours using an inorganic acid solution, and when the viscosity of the konjac flour is less than 100 mPa·s, adjust the pH of the solution to neutral, freeze-dry, and obtain konjac flour; Wherein, the addition amount of konjac flour is 50-80g / L.

2. the preparation method of konjak special flour according to claim 1, is characterized in that, The inorganic acid solution is hydrochloric acid, acetic acid, phosphoric acid or tartaric acid solution.

3. the preparation method of konjak special flour according to claim 1, is characterized in that, The concentration of the inorganic acid solution is 0.1 mol / L to 0.3 mol / L.

4. The method for preparing the konjak flour according to any one of claims 1 to 3, wherein: The konjac flour is konjac refined flour and / or konjac coarse flour.

5. the preparation method of konjak special flour according to claim 4, is characterized in that, The particle size of konjac refined flour is between 0.125 and 0.425 mm, accounting for more than 90%, and the particle size of konjac coarse flour is less than or equal to 0.425 mm, accounting for more than 90%.

6. The special konjac flour obtained by the preparation method according to any one of claims 1 to 5.

7. Use of the konjac flour according to claim 6 in preparing jelly, beverage or dietary fiber supplementary food.

8. Konjac dietary fiber supplement powder, characterized in that, The invention comprises special konjac flour. The preparation method of the special konjac flour comprises the following steps: mixing 0.1 mol / L hydrochloric acid solution with konjac flour at 85 DEG C, acid hydrolyzing for 2 hours, and adjusting the pH value to 7.0 when the viscosity of the konjac flour is less than 100 mPa·s to obtain the special konjac flour; wherein the addition amount of the konjac flour is 50 g / L, and the konjac flour is konjac refined flour or konjac coarse flour.

9. A konjac beverage, characterized in that: The invention comprises special konjac flour. The preparation method of the special konjac flour comprises the following steps: mixing 0.3 mol / L hydrochloric acid solution with konjac coarse powder at 85 DEG C, acid hydrolyzing for 2 hours, and adjusting the pH value to 7.0 when the viscosity of the coarse konjac powder is less than 100 mPa·s to obtain the special konjac flour; wherein the addition amount of the konjac flour is 50 g / L.

10. Konjac jelly, characterized in that The invention comprises special konjac flour. The preparation method of the special konjac flour comprises the following steps: mixing 0.1 mol / L hydrochloric acid solution with konjac powder at 55 DEG C, acid hydrolyzing for 1 hour, and adjusting the pH value to 7.0 when the viscosity of the konjac powder is less than 100 mPa·s to obtain the special konjac flour; wherein the addition amount of the konjac powder is 50 g / L.

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