CN108794776B

CN108794776B - Method for accelerating konjac gelation speed

Info

Publication number: CN108794776B
Application number: CN201810609545.0A
Authority: CN
Inventors: 吴平; 胡美琳; 余春磊; 范春相; 汪兵; 苟春鹏; 兰楚鹏
Original assignee: Hubei Yizhi Konjac Biotechnology Corp
Current assignee: Hubei Yizhi Konjac Biotechnology Corp
Priority date: 2018-06-13
Filing date: 2018-06-13
Publication date: 2020-11-27
Anticipated expiration: 2038-06-13
Also published as: CN108794776A

Abstract

The invention discloses a method for accelerating the gelling speed of konjak, which comprises the following steps: 1) mixing 100-120 parts of konjac flour and 4-6 parts of a cross-linking agent according to the weight part ratio to obtain a mixed material; 2) adding the mixed material obtained in the step 1) into water with the mass 30-50 times of that of the konjac flour for sol; 3) mixing 5-10 parts of gel and 1-3 parts of catalyst according to the weight part ratio, adding into the sol obtained in the step 2), and stirring for 1-2min in vacuum to obtain a jelly; 4) heating the jelly obtained in the step 3) at 90-95 ℃ for 10-15 min; thus obtaining the konjak instant gel. By the treatment, the aim of accelerating the konjac gelation speed is fulfilled. According to the invention, calcium oxide is used as a gelling agent, so that the gelling induction period can be shortened, the gelling rate can be increased, and the formed gel has a more uniform structure; the catalyst is beneficial to rapid deacetylation and accelerating the formation of hydrogen bonds, and the cross-linking agent can increase the network structure of konjac glucomannan, enhance the water retention performance and obtain a gel product with higher strength.

Description

Method for accelerating konjac gelation speed

Technical Field

The invention relates to the technical field of konjak, in particular to a method for accelerating the gelling speed of konjak.

Background

Konjak is the only economic crop which is found at present and can provide glucomannan in a large amount, and the use value of konjak in the field of food and medicine is continuously developed and displayed. Because the konjac glucomannan has various unique physicochemical properties of water solubility, thickening, stability, suspension, gelation, adhesion, film formation and the like, the konjac glucomannan has wide application and development values, wherein a plurality of konjac vegetarians with rich nutrition, convenience for eating, high quality and low price are developed by utilizing the gel property of the konjac glucomannan in a competitive way, and the production efficiency can be improved by increasing the speed of the konjac gel in the production process.

At present, the method or the process for accelerating the konjac gel speed is mainly to raise the temperature, and the common heating mode is external heating at present, so that the condition that the quality and the structure of the gel are not uniform due to nonuniform local heating exists. The invention patent with Chinese patent number CN201410652453.2 discloses a konjak bean curd and a preparation method thereof, the method needs more than 3 hours for thermally irreversible gelation, and the production efficiency is extremely low. The invention patent with Chinese patent number CN201210461261.4 discloses a preparation method of konjak tofu, which is characterized in that the method obtains thermally irreversible gel by heating for 30-50min at 80-90 ℃ under alkaline condition, and the like, and the method has the problems of long heating time and low production efficiency. The invention patent with Chinese patent No. CN201510636835.0 discloses a production method of konjak bean curd powder and a product thereof, the method adopts covering and standing for 5-6 minutes in the process of thermally irreversible gelation, and then boiling for 15-20 minutes with medium and large fire for hardening, although the method shortens the gelation time, the problem of incomplete gelation exists.

Disclosure of Invention

In order to solve the above problems, the present invention provides a method for accelerating the gelling speed of konjak, which can shorten the gelling time of konjak.

The technical scheme adopted by the invention is that the method for accelerating the konjac gelation speed comprises the following steps:

1) adding 100-120 parts by weight of konjac flour into 4-6 parts by weight of a cross-linking agent for mixing, and then adding into water for sol;

2) mixing 5-10 parts of gel and 1-3 parts of catalyst, adding into the sol obtained in the step 1), and stirring in vacuum for 1-2min to obtain a jelly;

3) heating the jelly obtained in the step 2) at 90-95 ℃ for 10-15 min; obtaining the konjak instant gel;

the aim of accelerating the konjac gelation speed is achieved through the treatment of the steps.

Further, the konjac flour is common konjac flour or purified konjac flour or instant konjac flour. The instant konjaku flour can be quickly swelled, the characterization of konjaku flour sol is water absorption swelling, and konjaku gel is formed under the conditions of alkalinity and heating after the konjaku flour is subjected to water absorption swelling, so that the time for forming gel in the whole process is shorter by selecting the instant konjaku flour.

Further, the konjac flour is prepared by taking konjac species as a raw material, the viscosity is greater than 32000mPa, and the swelling speed (1 wt%, 30 ℃) of the konjac flour is greater than 6000 mPa.s/min.

Further, the cross-linking agent is any one or more of chitosan, propylene oxide, carboxymethyl starch and glutaraldehyde.

Further, the catalyst is one or more of calcium phosphate, potassium sulfate and calcium dihydrogen phosphate.

Further, the gel is calcium oxide or a mixture of calcium oxide and calcium chloride.

Further, the heating is water bath heating, steam heating or microwave heating, preferably steam heating.

Further, the gel is prepared from calcium oxide and calcium chloride according to the weight ratio of 3: 1. The konjac flour can form a thermal irreversible gel under an alkaline condition, calcium oxide and calcium chloride are used simultaneously, the calcium ion concentration is increased, the gelling speed is higher, and the gel texture is tighter.

Further, when the sol in water is added in the step 1), the adding amount of the water is 30-50 times of the mass of the konjac flour.

The invention has the following beneficial effects:

1. when the konjak powder forms the thermal irreversible gel, the thermal irreversible gel is generally formed by adding alkali for reaction, calcium oxide or calcium oxide and calcium chloride are adopted as the gel agent in the invention, calcium hydroxide is generated by the reaction of calcium oxide and water and heat is released at the same time, so that not only is an alkaline substance provided for promoting the gel reaction, but also the heat is released from the inside, and the gel formed by external heating has uniform structure, and the required gel time is shortened. However, if calcium oxide is directly added into the sol to react with water, the safety hazard exists, and the addition amount needs to be well controlled.

2. The addition of the cross-linking agent can increase the network structure of the konjac glucomannan, enhance the water retention performance and obtain a gel product with compact texture and higher strength.

3. The addition of the catalyst is beneficial to rapid deacetylation and the formation of hydrogen bonds between glucomannan molecular chains is accelerated.

4. After the mixed material of the gel and the catalyst is added into the sol, vacuum stirring is carried out, so that bubbles can be prevented from being generated, and the gel structure is more compact.

Drawings

FIG. 1 is a graph showing the relationship between the gel strength and time of konjac flour treated in comparative example 1 and example 1 of the prior art.

Fig. 2 is a graph showing the gel strength of the konjac flour of comparative example 2 and that of the konjac flour treated in example 4 as a function of time.

Detailed Description

The invention is further described with reference to the following examples and the accompanying drawings, but the scope of the invention as claimed is not limited to the examples.

Comparative example 1:

adding common rhizoma Amorphophalli powder into water 30 times of its mass at normal temperature under stirring for 60min, adding calcium hydroxide or calcium carbonate as gelling agent after rhizoma Amorphophalli powder is fully swelled, and heating with steam for 30min for gel forming.

Example 1:

the method for accelerating the gelation speed of the konjak comprises the following steps:

1) taking 100 parts by weight of common konjac flour, adding 5 parts by weight of chitosan, mixing, and then adding 300 parts by weight of normal-temperature water for sol for 40 min;

2) uniformly mixing 5 parts of calcium oxide and 1 part of monocalcium phosphate, adding into the sol, and stirring for 2min in vacuum; heating with steam for 15min at 90-95 deg.C to obtain instant gel.

The relationship between the gel strength and time of the konjac flour after the treatment of the comparative example 1 and the example 1 is shown in fig. 1, the gel strength of the konjac flour in the example 1 can be stabilized at 15min, the gel strength of the konjac flour in the comparative example 1 can be stabilized at 32min, and the gel strength of the konjac flour in the example 1 is slightly larger than that of the konjac flour in the comparative example 1.

Example 2:

1) mixing 120 parts of instant konjac flour, 4 parts of cross-linking agent chitosan and carboxymethyl starch according to the weight part ratio to obtain a mixed material;

2) adding the mixed material obtained in the step 1) into water with the mass 30 times that of the konjac powder, and carrying out sol for 15 min;

3) mixing 8 parts of gel, including 6 parts of calcium oxide and 2 parts of calcium chloride, with 1 part of catalyst calcium phosphate according to the weight part ratio to obtain a mixed material, adding the mixed material into the sol obtained in the step 2), and stirring for 1min in vacuum to obtain a jelly;

4) rapidly heating the jelly obtained in the step 3) for 10min by steam; thus obtaining the konjak instant gel.

Example 3:

1) mixing 110 parts of purified konjac flour and 5 parts of cross-linking agent propylene oxide according to the weight part ratio to obtain a mixed material;

2) adding the mixed material obtained in the step 1) into water with the mass 30 times that of the konjac powder, and carrying out sol for 30 min;

3) mixing 7 parts of gel calcium oxide and 2 parts of catalyst calcium phosphate according to the weight part ratio to obtain a mixed material, adding the mixed material into the sol obtained in the step 2), and stirring for 2min in vacuum to obtain a jelly;

4) rapidly heating the jelly obtained in the step 3) for 13min by steam; thus obtaining the konjak instant gel.

Comparative example 2:

1) mixing 120 parts of konjac powder and 6 parts of cross-linking agent glutaraldehyde according to the weight part ratio to obtain a mixed material;

2) adding the mixed material obtained in the step 1) into water with the mass 30 times that of the konjac powder, and carrying out sol for 60 min;

3) taking 8 parts of gel comprising 7 parts of calcium oxide and 1 part of calcium chloride according to the weight part ratio, adding the gel into the sol obtained in the step 2), and stirring for 2min in vacuum to obtain a jelly;

4) rapidly heating the jelly obtained in the step 3) for 20min by steam; thus obtaining the konjak instant gel.

Example 4:

3) taking 8 parts of gel comprising 7 parts of calcium oxide and 1 part of calcium chloride according to the weight part ratio, mixing with 2 parts of catalyst potassium sulfate to obtain a mixed material, adding the mixed material into the sol obtained in the step 2), and stirring for 2min in vacuum to obtain a jelly;

4) rapidly heating the jelly obtained in the step 3) for 12min by steam; thus obtaining the konjak instant gel.

The gel strength of the konjac flour treated in the comparative example 2 and the konjac flour treated in the example 4 is shown in a time-dependent graph in fig. 2, the gel strength of the konjac flour treated in the example 4 is stable within 12min, and the gel strength of the konjac flour treated in the comparative example 2 is stable within 20 min.

The above-described embodiments are merely preferred embodiments of the present invention, and should not be construed as limiting the present invention, and the scope of the present invention is defined by the claims, and equivalents including technical features described in the claims. I.e., equivalent alterations and modifications within the scope hereof, are also intended to be within the scope of the invention.

Claims

1. The method for accelerating the gel speed of the konjak is characterized by comprising the following steps of:

1) adding 100-120 parts by weight of konjac flour into 4-6 parts by weight of a cross-linking agent for mixing, and then adding into water for sol; wherein the cross-linking agent is any one or more of chitosan, propylene oxide, carboxymethyl starch and glutaraldehyde;

2) mixing 5-10 parts of gel and 1-3 parts of catalyst, adding into the sol obtained in the step 1), and stirring in vacuum for 1-2min to obtain a jelly; wherein the catalyst is one or more of calcium phosphate, potassium sulfate and calcium dihydrogen phosphate; the gel is prepared from calcium oxide and calcium chloride according to the weight ratio of 3: 1;

2. The method of claim 1, wherein: the konjak powder is common konjak powder or purified konjak powder or instant konjak powder.

3. The method of claim 1, wherein: the konjac flour is prepared by taking konjac species as a raw material, the viscosity is greater than 32000mPa, the addition amount is 1wt%, the temperature is 30 ℃, and the swelling speed of the konjac flour is greater than 6000 mPa.s/min.

4. The method of claim 1, wherein: the heating mode is water bath heating, steam heating or microwave heating.

5. The method of claim 1, wherein: when the sol in water is added in the step 1), the adding amount of the water is 30-50 times of the mass of the konjac flour.