阅读说明：本技术 一种从鲜龙须菜中提取琼胶的方法 (Method for extracting agar from fresh asparagus ) 是由 崔荣箱 吴仕鹏 程跃谟 于云霞 于 2021-01-13 设计创作，主要内容包括：本发明公开了一种从鲜龙须菜中提取琼胶的方法,属于琼胶的提取技术领域。该方法以鲜龙须菜为原料,经过水洗、切菜、脱水步骤后,再对其进行碱处理、水洗步骤,将水洗至中性的龙须菜进行酸处理、水洗；然后向水洗后的龙须菜加入次氯酸钠进行漂白之后水洗；向水洗后的龙须菜中加入有机酸,调节其pH至5.5,酸洗处理55min,酸洗脱色后进行水洗,水洗至中性后,再将龙须菜进行泡水漂洗；之后依次经提取、粗滤、精滤、冷却、隔膜板框脱水、破碎造粒、杀菌、烘干、粉碎磨粉,检测计量后得到琼胶。本发明方法可显著提高琼胶的提取率,且产品白度达到70°以上,纯度83％以上,该方法绿色无污染,可推广应用。(The invention discloses a method for extracting agar from fresh asparagus, belonging to the technical field of extraction of agar. The method takes fresh asparagus as raw material, and carries out alkali treatment and water washing after the steps of water washing, vegetable cutting and dehydration, and the asparagus washed to be neutral is carried out acid treatment and water washing; adding sodium hypochlorite into the washed asparagus for bleaching and then washing; adding organic acid into the washed asparagus, adjusting the pH value of the asparagus to 5.5, carrying out acid washing treatment for 55min, washing the asparagus after acid washing and decoloration, and then rinsing the asparagus by soaking water after the asparagus is washed to be neutral; and then sequentially carrying out extraction, rough filtration, fine filtration, cooling, diaphragm plate-and-frame dehydration, crushing granulation, sterilization, drying, crushing and grinding, and detecting and metering to obtain the agar. The method can obviously improve the extraction rate of the agar, the whiteness of the product reaches more than 70 degrees, the purity is more than 83 percent, and the method is green and pollution-free and can be popularized and applied.)

1. A method for extracting agar from fresh asparagus is characterized by sequentially comprising the following steps:

s1, washing, cutting vegetables and dehydrating

Washing fresh asparagus serving as a raw material with water, cutting into small sections, and dehydrating;

s2, alkali treatment and water washing

Adding 8-10% by mass of sodium hydroxide solution into the fresh asparagus dehydrated in the step S1, and heating for alkali treatment; after the alkali treatment is finished, adding water into the mixture for washing until the mixture is neutral;

s3, acid treatment and water washing

Adding concentrated sulfuric acid into the asparagus washed to be neutral in the step S2 for acid treatment, and adding water for water washing after the acid treatment;

s4 bleaching and washing with water

Adding sodium hypochlorite into the asparagus washed in the step S3 for bleaching, and then washing with water;

s5, acid washing treatment, water washing and water soaking rinsing

Adding organic acid into the asparagus washed by the water in the step S4, adjusting the pH value of the asparagus to 5.5, carrying out acid washing treatment for 55min, washing the asparagus after acid washing and decoloring, and then rinsing the asparagus by soaking water after the asparagus is washed to be neutral;

s6, extraction

Dewatering the asparagus rinsed by the water in the step S5, putting the asparagus into an extraction tank, adding a certain amount of tap water, adding more than 98% of oxidant sodium chlorite, heating to 100 ℃, extracting for 2 hours, and removing ferromanganese ions;

s7, coarse filtration

Rough filtering the glue solution extracted in the step S6, and adding a mixed filter aid in the rough filtering process, wherein the mixed filter aid is a mixture of a slow filter aid perlite and diatomite;

s8, fine filtering, cooling and diaphragm plate frame dewatering

Filtering the coarse filtered glue solution obtained by the coarse filtration in the step S7 through a plate frame to obtain a fine filtered glue solution; cooling the fine filtering glue solution, and then dehydrating the fine filtering glue solution in a diaphragm plate frame;

s9, crushing, granulating, sterilizing and drying

Crushing the rubber sheet obtained after the water treatment of the diaphragm plate frame in the step S8, granulating, sterilizing, and then drying in a drying system;

s10, grinding, detecting and metering

And (5) crushing the agar particles dried in the step (S9) to 80-120 meshes to obtain ground agar, detecting the ground agar, and metering, detecting and packaging the qualified agar to obtain the agar.

2. The method of claim 1, wherein the agar is extracted from fresh Gracilaria lemaneiformis, and the method comprises the following steps: in the step S1, water with the weight 6 times that of the fresh asparagus is added in the water washing process, and the washed fresh asparagus is cut into small sections of 20-30 cm.

3. The method of claim 1, wherein the agar is extracted from fresh Gracilaria lemaneiformis, and the method comprises the following steps: in step S2, the temperature is raised to 70 ℃ and alkali treatment is carried out, and the treatment time is 3 h.

4. The method of claim 1, wherein the agar is extracted from fresh Gracilaria lemaneiformis, and the method comprises the following steps: in step S3, the pH was adjusted to 2 by acid treatment for 50 min.

5. The method of claim 1, wherein the agar is extracted from fresh Gracilaria lemaneiformis, and the method comprises the following steps: in step S5, the organic acid is oxalic acid with the concentration of more than 95%, and the fresh asparagus is washed by acid and decolored until the fresh asparagus is uniformly white.

6. The method of claim 1, wherein the agar is extracted from fresh Gracilaria lemaneiformis, and the method comprises the following steps: in step S7, the weight ratio of the perlite to the diatomite is 6: 4-8: 2.

7. The method of claim 1, wherein the agar is extracted from fresh Gracilaria lemaneiformis, and the method comprises the following steps: in step S8, the fine filtrate is cooled to 40 ℃.

8. The method of claim 1, wherein the agar is extracted from fresh Gracilaria lemaneiformis, and the method comprises the following steps: in the step S9, sterilizing by adopting a steam heating mode, wherein the sterilizing temperature is 90 ℃, and the sterilizing time is 45-75 min; the drying temperature is 50 ℃, and the drying is carried out until the water content is not more than 15%.

9. The method of claim 6, wherein the agar is extracted from fresh Gracilaria lemaneiformis, and the method comprises the following steps: the weight ratio of the perlite to the diatomite of the slow filter aid is 7: 3.

Technical Field

The invention belongs to the technical field of extraction of agar, and particularly relates to a method for extracting agar from fresh asparagus.

Background

The asparagus is mainly distributed in Shandong, Fujian, Jiangsu, Guangdong, Zhejiang and other provinces in China, and the algae grows faster, especially in spring and autumn, so that the asparagus is suitable for large-scale cultivation. At present, the asparagus is mainly used as a raw material for producing agar and agarose or a feed for feeding abalone, and can be directly eaten.

Agar is used as the most main carbohydrate, and related research reports in the prior art use asparagus to extract agar, for example, application number 200710059966.2 discloses a method for simultaneously extracting phycoerythrin and agar from colloid-containing seaweed such as asparagus, which comprises the following specific steps: and extracting agar from residues of the crude extract, putting the residues obtained after the crude extract of phycoerythrin is extracted into a conical flask, adding distilled water, boiling for 1-3 hours at the temperature of 120-125 ℃, filtering by using gauze, adding distilled water into the filter residues again, boiling for 1-1.5 hours at the same temperature, filtering, combining the two filtrates, standing for 16-20 hours at normal temperature, and freezing overnight to obtain the agar.

Although agar is extracted from asparagus in the prior art, the prior art has the defects of low extraction rate and the like. Therefore, the research on the method for improving the extraction rate of the agar by using the asparagus as the raw material has certain theoretical and practical significance.

Disclosure of Invention

The invention aims to provide a method for extracting agar from fresh asparagus, which takes the fresh asparagus as a raw material, determines the optimal process condition for extracting the agar by improving the process condition, and ensures that the whiteness of the agar extracted by the method meets the requirement.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for extracting agar from fresh asparagus is characterized by sequentially comprising the following steps:

s1, washing, cutting vegetables and dehydrating

Washing fresh asparagus serving as a raw material with water, cutting into small sections, and dehydrating;

s2, alkali treatment and water washing

Adding 8-10% by mass of sodium hydroxide solution into the fresh asparagus dehydrated in the step S1, and heating for alkali treatment; after the alkali treatment is finished, adding water into the mixture for washing until the mixture is neutral;

s3, acid treatment and water washing

Step S2, adding concentrated sulfuric acid into the neutral asparagus for acid treatment, and adding water for water washing after the acid treatment;

s4 bleaching and washing with water

Adding sodium hypochlorite into the asparagus washed in the step S3 for bleaching, and then washing with water;

s5, acid washing treatment, water washing and water soaking rinsing

Step S4, adding organic acid into the washed asparagus, adjusting the pH value to 5.5, carrying out acid washing treatment for 55min, washing with water after acid washing and decoloration, and rinsing the asparagus after washing with water to be neutral;

s6, extraction

Dewatering the asparagus rinsed by the water in the step S5, putting the asparagus into an extraction tank, adding a certain amount of tap water, adding more than 98% of oxidant sodium chlorite, heating to 100 ℃, extracting for 2 hours, and removing ferromanganese ions;

s7, coarse filtration

S6, coarsely filtering the obtained glue solution, and adding a mixed filter aid in the coarse filtering process, wherein the mixed filter aid is a mixture of perlite and diatomite;

s8, fine filtering, cooling and diaphragm plate frame dewatering

S7, filtering the coarse filtered glue solution obtained by coarse filtration by a plate frame to obtain a fine filtered glue solution; cooling the fine filtering glue solution, and then dehydrating the fine filtering glue solution in a diaphragm plate frame;

s9, crushing, granulating, sterilizing and drying

Crushing the rubber sheet obtained after the water treatment of the diaphragm plate frame in the step S8, granulating, sterilizing, and then drying in a drying system;

s10, grinding, detecting and metering

And S9, crushing the dried agar particles to 80-120 meshes to obtain ground agar, detecting the ground agar, and metering, detecting and packaging the qualified agar to obtain the agar.

As a preferable scheme of the present invention, in step S1, water 6 times the weight of the fresh asparagus is added in the water washing process, and the washed fresh asparagus is cut into 20-30 cm small segments.

In another preferred embodiment of the present invention, in step S2, the temperature is raised to 70 ℃ and the alkali treatment is carried out for 3 hours.

More preferably, in step S3, the pH is adjusted to 2 by acid treatment and the treatment is carried out for 50 min.

More preferably, in step S5, the organic acid is oxalic acid with concentration of 95% or more, and the solution is acid-washed and decolorized until the fresh asparagus is uniformly white.

Preferably, in the step S7, the weight ratio of the perlite used as the slow filter aid to the diatomite is 6: 4-8: 2.

Preferably, in step S8, the fine filtrate is cooled to 40 ℃.

Preferably, in step S9, steam heating is used for sterilization, the sterilization temperature is 90 ℃, and the sterilization time is 45-75 min; the drying temperature is 50 ℃, and the drying is carried out until the water content is not more than 15%.

Preferably, the weight ratio of the perlite to the diatomite is 7: 3.

Compared with the prior art, the invention has the following beneficial technical effects:

the invention provides a method for extracting agar from fresh asparagus, which is characterized in that organic acid oxalic acid is added for acid treatment in the whole process step, and the oxalic acid can effectively remove algae pigment in the asparagus, so that the algae is uniformly white and the whiteness of the product is improved. Meanwhile, the oxalic acid has weak acidity, so that the strength of the agar is not damaged while the whiteness of the product is improved by 15% -20%; compared with the extraction process adopting a strong oxidant in the prior art, the method adopts the organic acid oxalic acid for treatment, so that the strength of the agar cannot be damaged.

More than 98 percent of sodium chlorite is added as an oxidant in the extraction step to remove the iron and manganese ions. Because sodium chlorite is a strong oxidant, soluble low-valence iron and manganese ions can be oxidized into insoluble high-valence iron and manganese ions, and then the insoluble high-valence iron and manganese ions are removed from the algae body by filtration, and the whiteness and the purity of the product can be improved by using the sodium chlorite as the oxidant; yet another factor is that: the oxidation of sodium chlorite is larger than that of sodium hypochlorite, and tests prove that if the operation is not carried out, part of soluble low-valence iron and manganese ions still remain in the asparagus body and are oxidized into reddish brown high-valence insoluble iron ions after drying, so that the color and luster of the product are influenced.

The invention adopts the mixture of the perlite and the diatomite as the mixed filter aid during rough filtration, the mixed filter aid has good filtration effect, the whiteness of the product reaches more than 70 degrees, and the purity is more than 83 percent. Tests prove that the filtering effect is best when the weight ratio of the perlite to the diatomite is 6:4 to 8: 2. The large particles of insoluble vegetable particles, coarse fibers, suspended matter, etc. are removed by filtration.

Compared with the prior art, the method for extracting the agar from the fresh asparagus provided by the invention can obviously improve the extraction rate of the agar, the whiteness of the product reaches more than 70 degrees, the purity is more than 83 percent, and the method is green and pollution-free and can be popularized and applied.

According to the method for extracting the agar from the fresh asparagus provided by the invention, in the whole method steps, the fresh asparagus is used as a raw material, the cost for drying the fresh asparagus in the sun and the storage cost are saved, and in addition, the average strength of the agar produced by using the fresh asparagus is higher than that of the agar produced by using the dry asparagus as the raw material in the prior art; because impurities such as silt and the like in the fresh asparagus are removed before the alkali treatment step, the alkali liquor in the alkali treatment step can be recycled. The method of the invention is taken as a whole, which saves cost and has obvious economic benefit.

Drawings

The invention is further described below with reference to the accompanying drawings:

FIG. 1 is a process flow chart of the present invention for extracting agar from fresh Gracilaria lemaneiformis.

Detailed Description

The invention provides a method for extracting agar from fresh asparagus, and in order to make the advantages and technical scheme of the invention clearer and clearer, the invention is described in detail with reference to specific embodiments.

The raw materials selected by the invention can be purchased from commercial sources.

As shown in fig. 1, the method for extracting agar from fresh asparagus of the invention comprises the following steps:

step one, washing and cutting vegetables: adding tap water 6 times of the amount of fresh thallus Gracilariae, washing with water to remove sand and other impurities, and cutting into 20-30 cm pieces.

Step two, dehydration: pumping the vegetable washing tank with water pump into a twisting cage net for dewatering, and feeding into an alkali treatment tank.

Step three, alkali treatment: adding tap water 6 times the amount of the dehydrated fresh asparagus into the dehydrated fresh asparagus as a solvent to prepare a sodium hydroxide solution with the mass concentration of 8-10%, heating to 70 ℃, treating for 3h, and removing SO₄ ^2-Pigments, proteins, etc. And recycling the waste alkali liquor.

Step four, washing: adding tap water with 6 times of vegetable amount to soak the thallus Gracilariae after alkali washing treatment for 5-6 times, each time for about 2 hr, until the pH is neutral after leaching water for 2 hr, performing acid treatment to destroy the cell wall structure of thallus Gracilariae.

Step five, acid treatment: adding 75Kg concentrated sulfuric acid into thallus Gracilariae washed to neutrality in each tank, adjusting pH to 2, treating for 50min, immediately adding water, and washing for 1 time.

Step six, washing: washing the pickled thallus Gracilariae with tap water 6 times of the amount of thallus Gracilariae for 20min, and adding water.

Step seven, bleaching: adding 50Kg of sodium hypochlorite with the available chlorine of about 8-12% into the washed asparagus, bleaching for 45min, immediately adding water, and washing for 1 time.

Step eight, washing: rinsing the bleached thallus Gracilariae with tap water 6 times of the amount of thallus Gracilariae for 10min, and adding water.

Step nine, acid washing treatment: adding organic acid (oxalic acid) 15Kg and 95% above into each tank of washed thallus Gracilariae, adjusting pH to 5.5, acid washing for 55min, decolorizing until fresh thallus Gracilariae appears white, adding water, and washing with water for 1 time.

Step ten, water washing and soaking: soaking and washing the pickled asparagus with tap water of which the amount is 6 times that of the pickled asparagus to be neutral.

Step eleven, soaking in water and rinsing: rinsing the asparagus soaked in the water which is washed to be neutral by tap water with the amount of 6 times of the amount of the asparagus for 4 to 6 hours.

Step twelve, extraction: dewatering the rinsed asparagus, putting the asparagus into an extraction tank, adding tap water with the amount 5 times that of the asparagus, adding more than 98% of oxidant sodium chlorite, heating to 100 ℃, extracting for 2 hours, and removing ferromanganese ions.

Step thirteen, rough filtration: and (3) roughly filtering the extracted glue solution, and adding a filter aid prepared by mixing perlite and diatomite according to a certain ratio into the filter aid in the process.

Step fourteen, fine filtration: and filtering the coarse filtered glue solution by a plate frame to obtain a fine filtered glue solution.

Step fifteen, cooling: and (4) passing the fine filtration glue solution through a heat exchanger, and cooling to 40 ℃. And (4) recycling the hot water. And (4) allowing the glue solution to enter a natural cooling system, cooling to normal temperature until uniform dehydrated gel is formed, and allowing the gel solution to enter a dehydration system.

Sixthly, dehydrating a diaphragm plate frame: the gel enters a full-automatic diaphragm plate frame squeezing and dehydrating system, is dehydrated until the water content of the rubber sheet is about 65-75%, and enters a crushing and granulating process.

Seventhly, crushing and granulating: and (4) crushing the dehydrated rubber and granulating.

Eighteen, sterilization: and (3) sterilizing the granulated agar particles for 45-75 min under the condition of heating the agar particles to 90 ℃ by steam. Discharging and feeding into a drying system.

Nineteen steps of drying: drying at 50 deg.C until the water content is not more than 15%. And entering a milling system.

Twenty, crushing and grinding: and (3) crushing the dried agar particles to 80-120 meshes according to the requirements of customers, sieving and removing iron.

Twenty one, detecting and metering: and detecting the milled agar, and measuring, probing and packaging after the milled agar is qualified to obtain an agar product.

The present invention will be described in detail with reference to specific examples.

Example 1:

a method for extracting agar from fresh asparagus sequentially comprises the following steps:

s1, washing, cutting vegetables and dehydrating

Taking fresh asparagus as a raw material, washing the fresh asparagus with water, cutting the fresh asparagus into small sections of 20-30 cm by using the water in an amount which is 6 times of the amount of the fresh asparagus, dehydrating the small sections, and pumping the small sections into a stranding cage net from a vegetable washing tank by using a water pump for dehydration;

s2, alkali treatment and water washing

Pumping the fresh asparagus dehydrated in the step S1 into an alkali treatment tank, adding a sodium hydroxide solution with the mass fraction of 8% into the alkali treatment tank, heating to 70 ℃ for alkali treatment for 3 hours; the purpose of the alkali treatment is to remove SO₄ ^2-Adding tap water with the amount of 6 times of the vegetable amount into the mixture after the alkali treatment is finished, and washing the mixture for 5-6 times, wherein the washing time is about 2 hours each time, and the pH value is neutral after the leaching water is leached for 2 hours;

s3, acid treatment and water washing

S2, adding 75Kg of concentrated sulfuric acid into the asparagus washed to be neutral for acid treatment, adding water for water washing after acid treatment, washing the asparagus after acid treatment with tap water 6 times of the amount of the asparagus, and adding water for 20 min;

s4 bleaching and washing with water

Adding 50Kg of sodium hypochlorite with about 8-12% of available chlorine into the asparagus washed in the step S3, bleaching for 45min, immediately discharging water, and washing for 1 time;

s5, acid washing treatment, water washing and water soaking rinsing

S4, adding 15Kg of organic acid with the concentration of more than 95% into the water-washed asparagus, adjusting the pH value to 5.5, carrying out acid washing treatment for 55min, carrying out acid washing and decoloring until the asparagus is white, then carrying out water washing, washing until the asparagus is neutral, and then rinsing the asparagus by soaking water;

s6, extraction

Dewatering the asparagus rinsed by the water in the step S5, putting the asparagus into an extraction tank, adding a certain amount of tap water, adding more than 98% of oxidant sodium chlorite, heating to 100 ℃, extracting for 2 hours, and removing ferromanganese ions;

s7, coarse filtration

S6, coarsely filtering the obtained glue solution, and adding a mixed filter aid in the coarse filtering process, wherein the mixed filter aid is a mixture of a slow filter aid perlite and diatomite, and the weight ratio of the perlite to the diatomite is 6: 4;

s8, fine filtering, cooling and diaphragm plate frame dewatering

S7, filtering the coarse filtered glue solution obtained by coarse filtration by a plate frame to obtain a fine filtered glue solution; cooling the fine filtering glue solution to 40 ℃, then, entering a diaphragm plate frame for dehydration until the water content of the rubber is about 65-75%, and entering the next crushing and granulating process;

s9, crushing, granulating, sterilizing and drying

Crushing the rubber sheet obtained by the step S8 after being washed by water through a diaphragm plate frame, granulating, heating to 90 ℃ through steam, sterilizing for 45-75 min, and then drying in a drying system at the temperature of 50 ℃ until the water content is not more than 15%;

s10, grinding, detecting and metering

And S9, crushing the dried agar particles to 80-120 meshes to obtain ground agar, detecting the ground agar, and metering, detecting and packaging the qualified agar to obtain the agar.

Example 2:

the difference from the embodiment 1 is that: in the step S7 of coarse filtration, the weight ratio of the perlite and the diatomite of the slow filter aid is 7: 3.

Example 3:

the difference from the embodiment 1 is that: in the step S7 of coarse filtration, the weight ratio of the perlite and the diatomite of the slow filter aid is 8: 2.

The results of the correlation tests on the agaragar obtained in examples 1 to 3 are shown in table 1.

TABLE 1

The parts which are not described in the invention can be realized by taking the prior art as reference.

It should be noted that: any equivalents or obvious modifications thereof which may occur to persons skilled in the art and which are given the benefit of this description are deemed to be within the scope of the invention.