CN111349182A

CN111349182A - Preparation process of sodium alginate

Info

Publication number: CN111349182A
Application number: CN201811567029.2A
Authority: CN
Inventors: 王雷; 缪铭; 夏小乐
Original assignee: Ningbo Yingqian Technology Co ltd
Current assignee: Ningbo Yingqian Technology Co ltd
Priority date: 2018-12-20
Filing date: 2018-12-20
Publication date: 2020-06-30

Abstract

The invention discloses a preparation process of sodium alginate, which comprises the following process steps: pretreatment → pulverization, digestion → filtration, washing → acid coagulation → alkali neutralization → ethanol precipitation → filtration and impurity removal → drying → product. The invention adopts formaldehyde to carry out soaking pretreatment on the kelp, is beneficial to the replacement and dissolution of the sodium alginate in the digestion process, and improves the yield of the product. The sodium carbonate is adopted for the digestion process, so that the digestion time is greatly shortened, and the whole process efficiency is improved. The preparation method is simple in preparation process, low in preparation cost and suitable for industrial production.

Description

Preparation process of sodium alginate

Technical Field

The invention relates to the technical field of biochemical engineering, in particular to a preparation process of sodium alginate.

Background

Sodium alginate is a by-product after iodine and mannitol are extracted from kelp or gulfweed of brown algae, molecules of the sodium alginate are formed by connecting β -D-mannuronic acid and α -L-guluronic acid according to a (1 → 4) bond, the aqueous solution of the sodium alginate has high viscosity and is used as a thickener, a stabilizer, an emulsifier and the like of food, the sodium alginate is nontoxic food and is imported into the United states pharmacopoeia as early as 1938, the sodium alginate contains a large amount of-COO-, can show polyanion behavior in the aqueous solution, has certain adhesiveness and can be used as a drug carrier for treating mucosal tissues, the condition for forming gel by the sodium alginate is mild, and the inactivation of active substances such as sensitive drugs, proteins, cells, enzymes and the like can be avoided.

In the existing method, the process flow of sodium alginate is generally as follows: crushing dry or wet seaweed (algae), washing with water to remove impurities, extracting with strong alkaline water, clarifying to obtain crude alginate solution, precipitating with calcium chloride to obtain colored calcium alginate, decolorizing, deodorizing, treating with acid to remove soluble impurities to obtain alginic acid precipitate, reacting with sodium carbonate to obtain sodium alginate, drying, pulverizing, and sieving to obtain sodium alginate powder. However, the existing process has complex steps and high production cost, and the obtained sodium alginate product has serious degradation, low purity and lower average yield.

Disclosure of Invention

The invention aims to solve the technical problem of providing a preparation process of sodium alginate.

The technical scheme adopted by the invention for solving the technical problems is that the preparation process of the sodium alginate comprises the following preparation steps:

pretreatment → pulverization, digestion → filtration, washing → acid coagulation → alkali neutralization → ethanol precipitation → filtration and impurity removal → drying → product.

(1) Pretreatment: taking a certain amount of kelp, adding clear water 10-15 times the weight of the kelp and 1-2% of formaldehyde, and soaking for 2-4h at room temperature. After the soaking, the kelp is taken out and washed by water until the washing liquid is colorless.

(2) Crushing and digesting: cutting the kelp pretreated in the step (1) in a crusher, adding a sodium carbonate solution with a certain proportion and a certain concentration, and digesting under certain conditions;

(3) filtering and washing: adding water with the volume of 1-2 times that of the digested kelp raw material liquid in the step (2) for dilution, and then carrying out suction filtration on the filtrate by using a vacuum pump;

(4) adding acid for coagulation: slowly adding diluted hydrochloric acid with a certain concentration into the feed liquid filtered in the step (3) at normal temperature until flocculent precipitates, standing for 8-12h, continuously slowly adding diluted hydrochloric acid into the standing liquid, adjusting the pH value to 1.5-3, removing the supernatant, and leaving acid clots;

(5) adding alkali for neutralization: adding a sodium carbonate solution with a certain concentration into the acid coagulation block obtained in the step (4) under stirring at normal temperature to dissolve the acid coagulation block until the pH value is 7-8;

(6) ethanol precipitation: adding 4-5 times volume of 95% ethanol into the neutralized solution in the step (5) to separate out white precipitate;

(7) and (3) filtering and drying: and (4) filtering the white precipitate obtained in the step (6) by using a plate frame, and performing spray drying to obtain a sodium alginate finished product.

In a further technical scheme, in the step (2), the amount of the sodium carbonate solution added is 3-6 times of the mass of the kelp, the concentration is 10-20%, and the digestion temperature is 35-40 ℃.

In a further technical scheme, the concentration of the dilute hydrochloric acid in the step (4) is 5-10%.

In a further technical scheme, the concentration of the sodium carbonate solution in the step (5) is 5-10%.

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

(1) the French name adopts formaldehyde to soak the kelp for pretreatment, has a destructive effect on kelp cell wall fiber tissues, is beneficial to replacement and dissolution of sodium alginate in a digestion process, and improves the yield of products.

(2) In the kelp digestion process, sodium carbonate is adopted, so that kelp cells can be more easily permeated, the digestion time is greatly shortened, and the whole process efficiency is improved.

(3) The preparation method is simple in preparation process, low in preparation cost and suitable for industrial production.

Detailed Description

For a better understanding of the present invention, reference is made to the following examples. It is to be understood that these examples are for further illustration of the invention and are not intended to limit the scope of the invention. In addition, it should be understood that the invention is not limited to the above-described embodiments, but is capable of various modifications and changes within the scope of the invention.

Example 1

Taking a certain amount of kelp, adding clear water which is 10 times of the weight of the kelp and 2 percent of formaldehyde, and soaking for 3 hours at room temperature. After the soaking, the kelp is taken out and washed by water until the washing liquid is colorless.

Cutting the pretreated kelp in a grinder, adding a sodium carbonate solution with the mass ratio of 3-6 times that of the kelp and the concentration of 10-20% at the temperature of 37 ℃, and digesting at the temperature of 35-40 ℃;

adding 2 times of water to dilute the kelp raw material solution digested by the sodium carbonate solution, and then carrying out suction filtration on the filtrate by using a vacuum pump; slowly adding diluted hydrochloric acid with a certain concentration of 6% into the filtered feed liquid at normal temperature until flocculent precipitate begins, standing for 8h, continuously slowly adding diluted hydrochloric acid with a concentration of 6% into the standing liquid, adjusting the pH value to 2, discarding the supernatant, and leaving acid clot;

adding 8% sodium carbonate solution into the acid coagulation block under stirring at normal temperature to dissolve the acid coagulation block until the pH value is 7.5;

adding 5 times volume of 95% ethanol into the neutralized solution to precipitate white precipitate; filtering the white precipitate with a plate-and-frame filter, and spray drying to obtain sodium alginate finished product.

As described above, the present invention can be preferably implemented.

Claims

1. The preparation process of sodium alginate is characterized by comprising the following preparation steps:

(4) adding acid for coagulation: slowly adding diluted hydrochloric acid with a certain concentration into the feed liquid filtered in the step (3) at normal temperature until flocculent precipitates, standing for 8-12h, continuously slowly adding diluted hydrochloric acid into the standing liquid to adjust the pH value to 1.5-3, discarding the supernatant, and leaving acid clots;

2. The preparation process of sodium alginate as claimed in claim 1, which is characterized in that: in the step (2), the amount of the added sodium carbonate solution is 3-6 times of the mass of the kelp, the concentration is 10-20%, and the digestion temperature is 35-40 ℃.

3. The preparation process of sodium alginate as claimed in claim 1, which is characterized in that: the concentration of the dilute hydrochloric acid in the step (4) is 5-10%.

4. The method for preparing porphyra polysaccharide according to claim 1, wherein the method comprises the following steps: the concentration of the sodium carbonate solution in the step (5) is 5-10%.