JPS6176502A - Production of partially amidated pectin - Google Patents

Abstract

PURPOSE:To produce an amidated pectin having high quality, without lowering, molecular weight, in high efficiency, by treating a pectin-containing vegetable with an acid to effect the partial demethoxylation, separating the pectin, and treating the separated pectin with ammonia. CONSTITUTION:A dried pectin-containing vegetable (e.g. peel of citrus fruit) is swollen with an acid (usually an >=0.1N aqueous solution of an inorganic acid such as hydrochloric acid, sulfuric acid, etc. in an amount of 0.5-2.0g- equivalent % based on 1kg of the dry vegetable) to effect the partial de methoxylation of pectin. If necessary, the system is added with additional acid, and water is added thereto to effect the dissolution of pectin. After separating the insoluble component, the pectin is precipitated, the precipitate is treated with ammonia water under the condition to keep the precipitate essentially from dissolution, and the product is subjected to the simultaneous demethoxylation and amidation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing pectin. More specifically, when pectin is extracted from pectin-containing plants such as citrus peel, amide-type pectin is produced by partially demethoxylating and partially amidating the ester part of D-galacturonic acid, which is partially methyl esterified in pectin. Relating to a manufacturing method.

The properties of pectin vary depending on the degree of methoxylation of D-galacturonic acid in the pectin molecule.
% or more is methoxyl (HM) pectin, 5
Those with 0% or less are classified as loume h+sil (LM) pectin. Roughly speaking, the gelation rate of HM pectin varies depending on its degree of methoxylation, so it can be used as rapid set, medium set, or
It is divided into slow cents. LM pectin,
Even with N, properties such as gel hardness and elasticity vary depending on the degree of methoxylation, so adjusting the degree of methoxylation is important in producing pectin.

In addition, there are two types of LM pectin: LM pectin extracted with acid, etc., and partially amidated LM pectin. Partially amidated pectin has a wide range of optimal calcium concentration for gelation with calcium, and produces good gelation. can be easily obtained, and furthermore, it has the characteristics that it is easy to obtain a gel with relatively high strength.

[Prior art] If pectin is produced without demethoxylation of pectin, for example, pectin from squeezed lemon peel will yield 70%
The so-called Lapindose hH has a high degree of methoxylation, ~75%, and about 67-72% from orange juice peel.
Only M pectin can be obtained. In order to obtain pectin with a desired degree of methoxylation, it is necessary to demethoxylate it with an acid, an alkali, or an enzyme. At this time, ammonia is used as the alkali, and at the same time, partial amidation occurs to obtain a partially amidated pectin.

Partially amidated LM pectin can be produced by treating crude pectin obtained by extraction and precipitation in a normal pectin production process with a mixture of ammonia and alcohol, or by treating crude pectin with an acid-containing alcohol and then treating it with ammonia and alcohol. There is a method of treating with 62 compounds.

[Problems to be Solved by the Invention] Among these methods, the former method performs demethoxylation and partial amidation in one step, so demethoxylation must be carried out to the necessary extent, so the ammonia concentration must be increased.
It is necessary to increase the response time or increase the reaction time. When demethoxylation is carried out under such harsh conditions, especially in the presence of an alkali such as ammonia, a decrease in the molecular weight of pectin, that is, a decrease in quality, due to cleavage of glycosidic bonds is unavoidable, and in some cases, the yield of ti products also decreases. .

In the latter case, the first stage treatment method is to adjust the volume ratio of acid aqueous solution/alcohol to the obtained dehydrated precipitate from 1/1 to 1/1.
2, the weight/volume ratio of the precipitate/acid-containing alcohol is 1
/1 to 1/3 and the concentration of acid to the entire system is 1 to 1/3.
The reaction is carried out for several tens of hours at about 3N. To terminate this reaction, there is a method of neutralizing the system by adding alkali to it, but since the acid concentration is high when using this method, a large amount of alkali is required for neutralization, and the precipitate must be squeezed and dried. However, a large amount of salt (approximately 20%) remains in the product, reducing the quality of the product. To avoid this, a method is usually used in which excess acid is removed by repeatedly washing with water-containing alcohol when the reaction is terminated.

The precipitate thus obtained needs to be treated with a mixture of ammonia and alcohol and then washed again in the same manner, which creates problems such as complicated operations, complicated equipment, increased amount of alcohol used, and high costs. be.

The object of the present invention is to provide an efficient method for producing partially amidated pectin without such problems.

[Means for Solving the Problems] The gist of the present invention is to partially demethoxylate pectin by swelling a dry pectin-containing plant with acid, then dissolve the pectin, separate the undissolved components, and then dissolve the pectin. is precipitated, and the resulting precipitate is partially demethoxylated by acting on aqueous ammonia in a state in which the precipitate is not substantially dissolved.
The present invention relates to a method for producing partially amidated pectin. That is, the method involves treating a pectin-containing plant with an acid to lower the degree of methoxylation, separating the pectin, and then further demethoxylating the pectin with ammonia and simultaneously amidating it.

Acids used in the present invention include salts, ##, sulfuric acid,
Inorganic acids such as nitric acid are preferably used. Organic acids such as acetic acid and citric acid can also be used, but they have the disadvantage of low yields.・Demethoxylation with acid is carried out by adding acid to dry pectin-containing plants, but it is preferable that the concentration of the added acid is 0.1 N or more. If it is lower than this, the reaction will take a long time. It becomes necessary. The acid can be added by any method such as spraying or blending using a blender, but it is particularly preferable to take care to uniformly mix the acid and the plant.

Since the acid acts as a catalyst in demethoxylation, the amount of acid is not particularly limited, but the dry weight of the plant is 1 kg.
It is preferable to use about 0.5 to 2.0 gram equivalent % with respect to g. The acid used in demethoxylation can be used for both demethoxylation and extraction by adding more acid if necessary without removing it as is, and by adding water to adjust the concentration and extraction. Preferably, the amount of vinegar used for demethoxylation may be greater than the amount of acid used for extraction;
If the sample amount is exceeded, partial cleaning or neutralization will be required before extraction. Therefore, it is preferable that the amount of acid used for demethoxylation is equal to or less than the amount of acid required for extraction.

Further, it is preferable to use an amount of the aqueous acid solution for demethoxylation that is equal to or less than the weight of the plant in a dry state. This is because if there is an unnecessary amount of water compared to the required acid, the concentration of the acid will decrease and the reaction time will become longer, so the amount of aqueous solution is determined by the weight of the dry plant due to the balance between the ease of uniform mixing and the reaction time. This is due to the discovery that it is preferable that the amount is as follows. Even if a concentrated acid is used, there is no particular problem as long as it can be blended uniformly, so there is no upper limit on the acid concentration. For example, when using a spray method, a relatively thick layer of acid can be used. After the plant is impregnated with acid, it is preferable to keep the plant sealed during the demethoxylation reaction to prevent changes in concentration due to evaporation of water, etc. Adjust the degree of methoxylation of pectin to the desired value in the first stage.
To achieve this, the demethoxylation reaction time, acid concentration, amount of oxidation, reaction temperature, etc. may be adjusted as appropriate.

In the treatment with aqueous ammonia, it is necessary to perform the treatment in a state in which the precipitate is not substantially dissolved.

That is, it is preferable to perform the treatment using a mixed solution of an aqueous ammonia solution and a water-miscible organic solvent. The volume ratio of the ammonia aqueous solution and the water-miscible organic solvent is preferably 171 to 1/2, and the weight/volume ratio of the precipitate and the mixed solution is preferably 1/1 to 1/3. The concentration of ammonia in the entire system is preferably about 0.5 to 1.5 normal, and under these conditions, the required reaction time at room temperature may be about 30 minutes to several hours. If the ammonia concentration in the system is too low, the reaction will take a long time, which is undesirable; if it is too high, the reaction rate will be too fast, making control difficult.

[Example] The present invention will be explained in more detail below using Examples.

In the examples, the degree of methoxylation and the degree of amidation are determined from the Fundo Chemicals Codex (FoodC: hem.
icals Codex) 3rd edition. Further, the gel strength was measured using a neocadmeter after preparing a gel having a composition of 31% sugar content, PH 3.0, 1% pectin, and 250 mg/kg calcium.

Example One liter of 3N hydrochloric acid aqueous solution was added and mixed to 3.0 kg of dried squeezed fruit peel of Lumon. The peel became swollen with this aqueous solution. This was placed in a polyethylene bag, sealed, and left at 25°C for 72 hours. The sample peel was placed in an extraction tank, water was added to make the total amount 1,001, and the temperature was raised to 90°C for 30 minutes with stirring for extraction. The pH of the extract was 2.0. Next, undissolved matter was removed by centrifugation.

400g of diatomaceous earth filter aid was added to the obtained supernatant liquid, and filtered under pressure to obtain a clarification of 11! 7.8 kg was obtained. Isopropyl alcohol was added to the filtrate to give a volume concentration of 60%, and the precipitated pectin was separated.

By squeezing, 2.4 kg of precipitate with a solid content of 1 degree and 25% was obtained.

Add to this precipitate 60% volume concentration of isopropyl alcohol 4
．． 400mM of 25% ammonia water was added, stirred and mixed, and reacted for 3 hours.
0, and the precipitate was separated and squeezed. After adding twice the amount of isopropyl alcohol to this precipitate to dissolve the salts contained in the precipitate, the precipitate was separated and pressed again, then dried and crushed to obtain 58 g of powdered pectin. The degree of xylation (d) of the obtained pectin was 30.0%, and the degree of amidation was 16.3%. Also, the gel strength is 163g/cm
'Met.

The degree of methoxylation of pectin before ammonia treatment was 57.1%.

Example? 1550 mL of a 2.3N hydrochloric acid aqueous solution was added to 3.0 kg of dried squeezed orange peel and mixed. The peel became swollen with this aqueous solution. This was placed in a polyethylene bag, sealed, and left at 30°C for 20 hours. Below, as ammonia water treatment, 60% volume 8 concentration isopropyl alcohol 4-prong and 25% ammonia water 270mfL
Powdered pectin was obtained in the same manner as in Example 1 except that . Note that the pH at the time of extraction was 2.1. The degree of methoxylation of the obtained pectin was 36.4%, and the degree of amidation was 12.0%. Also, the gel strength is 148g/cr
The degree of methoxylation of pectin before ammonia treatment was 52.3%.

Comparative Example 1 The dry fruit peel was not swollen with an acid aqueous solution before being left sealed, and the conditions after extraction were as follows: 4 volumes of isopropyl alcohol with a volume concentration of 60% and 450 ml of 25% ammonia water were used as the ammonia water treatment. Dried lemon juice peel was prepared in the same manner as in Example 1 except that 3.0 k
Pectin was produced from g. The degree of methoxylation of the obtained pectin was 28.6%, and the degree of amidation was 20.3. Also, the gel strength is 124 g/c rrr'
Met. Pectin is usually used as a compound with the addition of an inexpensive diluent such as sugar or glucose, but adding a diluent reduces the gel strength. This compound requires a certain gel strength depending on its use, but with pectin having a gel strength of 124 g/ctn', it may not be possible to obtain a powder with the required gel strength, or even if it is obtained, it must be diluted. Since almost no agent can be added, the cost of the compound increases, which is economically disadvantageous.

[Effects of the Invention] As is clear from the above examples, the present invention, in which pectin-containing plants are treated with acid in advance and then treated with ammonia after separating the pectin, can obtain high-quality pectin, and is not as effective as in the prior art. It has the excellent effect that it does not cause an excessive decrease in the molecular weight of pectin, and that it is relatively easy to wash away salts generated by subsequent neutralization. In addition, it is economical because methoxylation can be controlled by the acid used for extraction.

Claims (1)

[Claims] 1. A precipitate obtained by swelling a dry pectin-containing plant with acid to partially demethoxylate the pectin, then dissolving the pectin to separate the undissolved components, and precipitating the pectin. A method for producing partially amidated pectin, which involves partially demethoxylating and partially amidating pectin by applying aqueous ammonia to the product in a state in which the precipitate is not substantially dissolved. 2. The method for producing pectin according to claim 1, wherein the amount of acid used for demethoxylation is equal to or less than the amount of acid required for extraction. 3. The acid used for demethoxylation is an aqueous solution, the concentration of the solution is 0.1N or more, and the amount of the solution is less than or equal to the weight of the plant in a dry state. A method for producing pectin according to claim 1.