WO2003072587A1

WO2003072587A1 - Process for producing nonvolatile thiazolidine compound

Info

Publication number: WO2003072587A1
Application number: PCT/JP2003/001362
Authority: WO
Inventors: Hirokazu Kawaguchi; Masanori Kohmura
Original assignee: Ajinomoto Co., Inc.
Priority date: 2002-02-28
Filing date: 2003-02-10
Publication date: 2003-09-04
Also published as: TW200303172A; JPWO2003072587A1; AU2003207194A1; MY139293A

Abstract

A novel process for producing a nonvolatile thiazolidine compound, characterized by holding a reducing sugar together with cysteine or/and cysteinyl-glycine or cystine in an aqueous medium with heating. By the process, a nonvolatile thiazolidine compound satisfactorily applicable to foods can be produced in a short time in a high yield.

Description

Method for producing nonvolatile thiazolidine compound

(Technical field)

The present invention relates to a novel method for producing a non-volatile thiazolidine compound which can be produced in a short time and at a high yield and has no problem for food use.

(Background technology)

The present applicant has found that a non-volatile thiazolidine compound is useful for enhancing the flavor or improving the flavor of foods and drinks by enhancing the flavor and masking of unpleasant odors, and based on such findings, `` Enhancing the flavor of foods and beverages '' Or a method for enhancing or improving the flavor of foods and beverages using the composition and the method for improving or improving the flavor of the food and drink using the composition (International Application No. PCT / JP01 / 077769 (WO 02/2)). 1 9 3 8 A 1)

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However, for non-volatile thiazolidine compounds having such usefulness, no excellent production method has been developed, and only a chemical synthesis method by Schubert et al. Has been reported (J. Biol. Chem., 130, 601 (1939)). In this method, cysteine hydrochloride (Cys · HC1) is dissolved in water, xylose is added thereto, left at room temperature for several days, pyridine is further added, left at room temperature for several days, and ethanol is added. And then purified by recrystallization from ethanol.

However, this method requires a long time of about one week to prepare the target compound, and the target compound obtained due to the use of a large amount of pyridine is not suitable for use in foods. There is.

(Disclosure of the Invention) [Problems to be solved by the invention]

An object of the present invention is to provide a production method capable of obtaining a non-volatile thiazolidine conjugate having utility as described in the preceding section in a short time and with a high yield.

[Means for solving the problem]

As a result of intensive studies to achieve the above object, the present inventors have found that cysteine hydrochloride and reducing sugars are dissolved in an aqueous solvent, neutralized with sodium hydroxide or the like, and heated to obtain a non-volatile compound. The present inventors have found that a thiazolidine compound can be obtained in a short time and at a high yield of about 80% with respect to cysteine, and based on such findings, the present invention has been completed.

That is, the present invention firstly relates to a method for producing a non-volatile thiazolidine compound, which comprises maintaining cysteine or Z and cystinyl glycine and a reducing sugar in an aqueous solvent under heating. The present inventor has further conducted intensive studies to achieve the above object, and found that cystine and reducing sugars were dissolved in an aqueous solvent instead of cysteine and / or cystinylglycine in an aqueous solvent, and the solution was alkalized with sodium hydroxide or the like. It was found that a non-volatile thiazolidine compound can be obtained in a short time and with a high yield of about 80% with respect to cysteine by heating, and the present invention was completed based on such findings.

That is, the present invention secondly relates to a method for producing a non-volatile thiazolidine compound, which comprises maintaining cystine and a reducing sugar in an aqueous solvent while heating.

[Embodiment of the invention]

Hereinafter, the present invention will be described in detail. When a non-volatile thiazolidine compound is produced by the production method of the present invention, the production conditions are almost the same when cysteine and / or cystinyldaricin are selected as the raw material and when cystine is selected, but there are still slight differences. . Therefore, hereinafter, first, the case where cysteine and / or cystinylglycine is selected as a raw material will be described, and then the case where cystine is selected as a raw material will be described. First, when cysteine and / or cystinyl glycine are used as a raw material, the non-volatile thiazolidine compound to be produced by the method of the present invention refers to a non-volatile derivative of thiazolidine having one or more substituents on a thiazolidine skeleton. Oproline and its derivatives and 2- (polyhydroxyalkyl) thiazolidine-4-carboxylic acids, specifically, 2- (1,2,3-trihydroxypropyl) thiazolidine-4-carboxylic acid, 2- (1,2 , 3,4-Tetrahydroxybutyl) thiazolidine-4-carboxylic acid, 2- (1,2,3,4,5-pentylhydroxypentyl) thiazolidine-4-carboxylic acid, 2-hydroxymethyl-2- (1 , 2,3,4-Tetrahydroxybutyl) thiazolidine-4-carboxylic acid, 2- (1,2,4,5-tetrahydroxy-3-darcoviranosyloxypentyl) thiazolidine-4-ca Bonic acid, 2- (1,2,3,4-tetrahydroxybutyl) thiazolidine-4-force Luponyl-N-glycine, 2- (1,2,3,4,5-penoxyhydroxypentyl) thiazolidine-4 -Carbonyl-N-glycine and the like.

According to the present invention, such a non-volatile thiazolidine compound may be a saccharide having a reducing group such as cysteine cis-tinylglycine and a monosaccharide such as xylose or glucose, or a disaccharide such as maltose or lactose. The sugar can be easily obtained by holding the composition in an aqueous solvent under heating, for example, under neutral to neutral conditions. To be more specific, it goes without saying that cysteine is preferably an integral L when the target non-volatile thiazolidine compound is used for food. Cysteine is usually used in the form of a hydrochloride salt, because its solubility is better in the form of a salt such as a hydrochloride salt than in the free form. By the way, cysteine hydrochloride is usually distributed in the form of monohydrate. In addition, cysteine (hydrochloride) must be used as long as the effects of the present invention are achieved. It does not need to be pure, and may be, for example, a yeast extract containing cysteine (hydrochloride). Cystinylglycine has a common chemical structure with cysteine, and exhibits the same chemical behavior as cysteine in the production method of the present invention. For these reasons, cysteine and cystinildaricin can be used alone or as a mixture of both as raw materials for the method for producing a nonvolatile thiazolidine compound of the present invention.

There is no particular limitation on the reducing sugar, and pentoses such as D-xylose, hexoses such as D-darcose, and disaccharides such as maltose can be used. In the method for producing a non-volatile thiazolidine of the present invention, cysteine or / and cystinyl glycine and reducing sugars react in equimolar amounts to give the target compound. It is preferable that the content is slightly excessive in view of the yield of cysteine or Z and cysteinylglycine of the objective compound.

The temperature to be kept under heating is 40 to 100 ° C, preferably 60 to 80 ° C. At low temperatures, it takes a long time to produce the target substance, while at high temperatures, the target substance can be produced in a short time, but it is not preferable because side reactions such as heating browning reaction easily occur. It is needless to say that cysteine and / or cysteinylglycine and reducing sugar are preferably kept under the above conditions until the production rate of the target compound is maximized. May be around 20 minutes (See Figure 1 below)

There are no particular restrictions on the pH when cysteine or cystinylglycine and reducing sugars are kept under the above conditions, but the stability of the target compound, a non-volatile thiazolidine compound, is better when the pH is higher. Is preferred. However, alkaline foods are rare, and from the viewpoint of using non-volatile thiazolidine compounds in foods, the pH at the start of maintaining the above conditions, that is, at the start of the reaction to produce the target compound, is, for example, pH About 8 to weakly alkaline to neutral are preferable. However, even if the reaction is started from weakly alkaline to neutral, non-volatile thiazolyz The pH gradually decreases with the generation of the compound, and the acid changes to slightly acidic. In this case, it is preferable to adjust the pH during the reaction to keep the pH in a preferable range. The target compound thus produced can be separated from the reaction mixture and used for food, but may be used as a reaction mixture (solution) as it is, or may be appropriately dried and powdered for distribution. Sodium chloride produced by the neutralization operation accompanies the reaction mixture and its dry powdered product, but it is clear that it does not particularly hinder its use in foods.

There are no particular restrictions on the pulverization method or the drying method. After completion of the reaction, the reaction mixture may be added with a solvent such as ethanol, crystallized, filtered and dried, or the reaction solution may be directly subjected to spray drying or freeze drying. It may be dried and powdered. The form of application of the nonvolatile thiazolidine compound thus obtained to foods can be appropriately determined by mixing powders and solutions. Next, the present invention when cystine is selected as a raw material will be described in detail.

When cystine is used as a raw material, the non-volatile thiazolidine compound to be produced by the method of the present invention refers to a non-volatile derivative of thiazolidine having one or more substituents on the thiazolidine skeleton, such as thioproline and its derivatives or 2- ( Polyhydroxyalkyl) thiazolidine-4-carboxylic acids, specifically, 2- (1,2,3-trihydroxypropyl) thiazolidine-4-carboxylic acid, 2- (1,2,3,4-tetrahydroxybutyl) Thiazolidine-4-carboxylic acid, 2- (1,2,3,4,5-pentanohydroxypentyl) thiazolidine-4-carboxylic acid, 2-hydroxymethyl-2- (1,2,3,4-tetra (Hydroxybutyl) thiazolidine-4-carboxylic acid, 2- (1,2,4,5-tetrahydroxy-3-darcopyranosyloxypentyl) thiazolidine-4-carboxylic acid, etc.

According to the present invention, such a non-volatile thiazolidine compound includes cystine and a sugar having a reducing group (reducing sugar) such as monosaccharides such as xylose and glucose, and disaccharides such as maltose and lactose. Initial pH in aqueous medium under alkaline conditions And can be easily obtained by holding under heating.

More specifically, it is needless to say that cystine is preferably integrated with L when the non-volatile thiazolidine compound of the target compound is used for food. Cystine may be in the form of free acid or in the form of hydrochloride, and is not necessarily a pure product as long as the effects of the present invention can be obtained. For example, cystine (eg, yeast extract containing cystine (hydrochloride)) may be used. It may be in a form.

There is no particular limitation on the reducing sugar, and pentoses such as D-xylose, hexoses such as D-darcose, and disaccharides such as maltose can be used.

In the method for producing a non-volatile thiazolidine compound of the present invention, first, cystine is cleaved at its SS bond by a reducing sugar, and then the resulting cysteine reacts with the reducing sugar in equimolar amounts to give the target compound. Conceivable. Therefore, the required amount of sugar is considered to be 3 moles per 1 mole of cystine. However, in practice, as shown in Example 3 below, not much is required. This is thought to be due to the fact that the reducing sugars are decomposed (under alkaline conditions) to produce new reducing substances, which are also involved in the cleavage of the SS bond. According to the present invention, the reducing sugar is at least 2 moles per mole of cystine, and the use of 2.2 moles can maximize the yield of cystine.

The temperature to be kept under heating is 25-100 ° C., preferably 60-90. C. At low temperatures, it takes a long time to produce the target substance, while at high temperatures, the target substance can be produced in a short time, but it is not preferable because side reactions such as heating browning reaction easily occur. Needless to say, it is preferable to maintain cystine and reducing sugar under the above conditions until the production rate of the target compound is maximized, but such a time is, for example, within about 15 minutes from the start of the retention. Sometimes (see Figure 2 below).

Regarding the pH when cystine and reducing sugars are maintained under the above conditions, reducing sugars show reducing properties when they are active, and those which are non-volatile thiazolidine compounds. Because of good stability, pH New However, even if the initial pH starts the reaction from an alkali such as pH 11, the pH rapidly drops at first to about pH 8, for example, and then the non-volatile thiazolidine compound As pH is generated, the pH gradually decreases and changes to a neutral range or a weakly acidic range (eg, pH 6.5).

The target compound thus formed can be separated from the reaction mixture and used for food as described above, but it may be used as a reaction mixture (solution) as it is, or may be appropriately dried and powdered. Can be put into circulation.

There are no particular restrictions on the pulverization method or the drying method. After completion of the reaction, a solvent such as ethanol is added to the reaction mixture, and the crystallized product may be filtered and dried, or the reaction solution may be directly subjected to spray drying or freeze drying. It may be dried and powdered. The form of application of the nonvolatile thiazolidine compound thus obtained to foods can be appropriately determined by mixing powders and solutions. These are the same as described above.

(Brief description of drawings)

FIG. 1 shows the effect of the heating temperature on the production rate of the nonvolatile thiazolidine compound (see Examples 1 and 2).

FIG. 2 shows the effect of the amount of added sugar on the production rate of the non-volatile thiazolidine compound (see Example 3).

FIG. 3 shows the effect of the type and amount of sugar on the production rate of the nonvolatile thiazolidine compound (see Examples 4, 1 and 3).

FIG. 4 shows the effect of the heating temperature on the rate of formation of the nonvolatile thiazolidine compound (see Examples 5 and 6).

FIG. 5 shows the effect of the amount of added sugar on the production rate of the non-volatile thiazolidine compound (see Example 7).

FIG. 6 shows the effect of the type of sugar on the production rate of the non-volatile thiazolidine compound (see Examples 8 and 6). (Best mode for carrying out the invention)

Hereinafter, the present invention will be described in more detail by reference examples and examples. Reference Example 1 (Conventional method): Synthesis of 2- (1,2,3,4-Tetrahydroxybutyl) thiazolidine-4-carboxylic acid:

A non-volatile thiazolidine compound was chemically synthesized by the method of Schubert et al. (J. Biol. Chem., 130, 601 (1939)). That is, 17.56 g (10 Ommo 1) of cysteine hydrochloride (monohydrate) and 15.01 (10 Ommo 1) of D-xylose were dissolved in 35 ml of pure water, and 8.36 ml of pyridine (10 Ommo 1) was added. After the addition, the mixture was stirred at room temperature for 72 hours. Then, 300 ml of ethanol was added and the mixture was allowed to stand in a refrigerator, whereupon a paste-like precipitate was formed. The solvent was removed by decantation, and the precipitate was dissolved in 100 ml of water. Then, the impurities were removed by filtration and concentrated to about 30 ml. Ethanol was added to the concentrate until just before precipitation occurred, and the mixture was allowed to stand in a refrigerator. The resulting crystals were collected by filtration and dried under reduced pressure. The dried crystals were dissolved again in water, the impurities were removed by filtration, concentrated, re-crystallized by adding ethanol again, and the resulting crystals were collected by filtration and dried under reduced pressure to obtain 10.8 g of a white powder. (42.7% yield to cysteine mol). First, examples of the present invention in which cysteine or cystinylglycine is used as a raw material will be described. Example 1

1.75 g (10. Ommo 1) of cysteine hydrochloride (monohydrate) was dissolved in 3.6 ml of distilled water, 1.58 g (10.5 mmol) of D-xylose was added, and the mixture was stirred and completely dissolved. . 2.3 g of a 27% sodium hydroxide solution was gradually added to this solution. At this time, the pH was about 8. Heat this solution to 60 ° C and keep it at the same temperature It was kept every time. During this time, the reaction solution was sampled appropriately, diluted 1000 times with distilled water, and the yield of the target compound was analyzed by HPLC under the conditions shown in Table 1 below.

HPLC system Waters “aliiance”

Column rCAPCELL PAK NH ₂ "(0.20 inner diameter x 250 customers)

Solvents Acetonitrile (Α) and 50 η »acid ammonium aqueous solution (Β)

Mixed solvent (mixing ratio: Α / Β = 50/50)

Flow m 0.2 ml / min.

Detection wavelength UV (210 dishes) Example 2

Example 1 was repeated in exactly the same manner, except that the temperature was changed to 40 ° C or 80 ° C instead of the temperature of 60 ° C. The results of Examples 1 and 2 are summarized in FIG. From FIG. 1, it can be seen that the retention time under heating at various temperatures and the fate of the formation of the target compound. As can be understood from FIG. 1, the production rate reaches 80% or more at 60 to 80 ° C. As used herein, the yield refers to the molar yield of the non-volatile thiazolidine compound from cysteine (hydrochloride) or / and cystinyl glycine. In addition, even if the holding time under heating is within 20 minutes, the generation rate is maximized and does not change thereafter. Example 3: Effect of amount of reducing sugar used on formation of target compound

Example 1 was repeated exactly the same except that the amount of xylose was changed to 12.5 mmol or 14.0 mmol instead of 10.5 mmol. Figure 2 summarizes the evolution of the production rate of the target compound at the three amounts of xylose used.

From FIG. 2, it can be seen that the xylose gives a production rate of the target compound of 80% or more with respect to cysteine hydrochloride at any of 1.05, 1.2 and 1.4 times the molar amount. In other words, if the amount of xylose is a small excess with respect to cysteine hydrochloride, Is sufficient for the maximum production of Example 4: Effect of sugar type on production of target compound

Dissolve 1.75 g (10. Omol) of cysteine hydrochloride (1.Omol) in 3.6 ml of distilled water, add 1.89 g (10.5 mmo 1) of D-glucose, stir and dissolve completely I let it. 2.3 g of a 27% sodium hydroxide solution was gradually added to the solution. At this time, the pH was about 8. This solution was heated at 60 ° C. and kept at the same temperature. During this time, the reaction solution was appropriately sampled, and the production rate of the target compound was analyzed in the same manner as in Example 1.

The same operation was performed by changing glucose 10.5 mmo 1 to 12.0 mmo 1. In order to examine the effect of the type of sugar on the production of the target compound, relevant data from the above Examples 4, 1, 1 and 3 are collected and summarized in FIG. This indicates that the production rate of the target compound is not significantly affected by the type of sugar. Next, examples of the present invention in which cystine is used as a raw material will be described. Example 5

1.0 g (4.2 mmo 1) of cystine is dissolved in 1.27 g of 27% aqueous sodium hydroxide solution, and D-xylose 1.75 g (l l. 7 mmo 1. 1 mol of cystine is equivalent to 2 mol of cysteine) Therefore, it becomes 1.4 times as much as that of cysteine.) And stirred to dissolve completely. Further, 1.Og of water was added, and the mixture was heated to 60 ° C and maintained at the same temperature. During this period, the reaction solution was appropriately sampled, diluted 1000 times with distilled water, and the yield of the target compound was analyzed by HPLC under the conditions shown in Table 1 above. Example 6

Example 5 is replaced with a temperature of 60 ° C. instead of 60 ° C. 98 ° C., 90 ° C., 70 ° C. or 50. The procedure was repeated in exactly the same manner except that C was used. The results of Examples 5 and 6 are summarized in FIG. In FIG. 4, the vertical axis indicates the yield obtained by converting the molar yield for cystine to the molar yield for cysteine (relative to the molar yield of Cys). The horizontal axis indicates the heating and holding time.

Figure 4 shows the retention time under heating at various temperatures and the fate of the formation of the target compound. As can be understood from Fig. 4, at 60 to 90 ° C, the production rate reaches 80% or more in the heating and holding time of 30 minutes to 2 hours. Example 7: Effect of amount of reducing sugar used on production of target compound

Example 5 was the same as Example 5 except that the temperature was changed to 90 ° C or 50 ° C instead of 60 ° C, and the amount of xylose was changed to 1.1 times or 1.4 times as much as cysteine at each temperature. Exactly the same was repeated. Figure 5 summarizes the evolution of the yield of the target compound for the two amounts of xylose used at each temperature.

Figure 5 shows that xylose was 1.1 times higher and 1

It can be seen that the production rate of the target compound is about 80% or more with any of the 4-fold molar amount.

. In other words, a small excess of xylose relative to cystine is sufficient for maximal production of the desired compound. Example 8: Effect of sugar type on production of target compound

In Example 5, the heating and holding temperature was 60. The procedure was exactly the same except that C was replaced by 70 ° C. and 1.75 g of D-xylose was replaced by 2.10 g (11.7 mmol) of D-glucose. In order to examine the effect of the type of sugar on the production of the target compound, relevant data from the above Examples 8 and 6 are collected and summarized in FIG. This indicates that xylose has a slightly higher production rate of the target compound than glucose. Example 9

Chicken consommé (Knol) Commercially available chicken consommé soup prepared by adding 600 ml of hot water to two cubes (14 g) The above is described above 3 The nonvolatile thiazolidine obtained in Example 1 A reaction mixture of the compound was added so that the concentration at the time of eating was 5 ppm in terms of the non-volatile compound, and the non-added compound was used as a control. An evaluation was performed. As a result, as shown in the table, the preference of the additive was significantly higher than that of the additive-free product. Table 2 Sensory evaluation of chicken consommé soup

* Significant difference with a risk factor of 5% or less

** Significantly different with a risk factor of 1% or less

Rating +2: Strong or favorable

+1: somewhat strong or slightly favorable

0: Same as additive-free product

One: slightly weak or slightly unfavorable

One-two: weak or unfavorable

(Industrial applicability).

According to the present invention, a non-volatile thiazolidine compound having no problem for food And can be produced in high yield <

Claims

The scope of the claims

1. A method for producing a non-volatile thiazolidine compound, comprising maintaining cysteine and / or cystinylglycine or cystine and a reducing sugar in an aqueous solvent under heating.

2. The method for producing a non-volatile thiazolidine compound according to claim 1, wherein the holding temperature of the cysteine and / or cystinylglycine under heating is 40 to 100 ° C.

3. The method for producing a nonvolatile thiazolidine compound according to claim 2, wherein the holding temperature under heating is 60 to 80 ° C.

4. The process for producing a non-volatile thiazolidine compound according to claim 2, wherein the holding under heating is performed under a weak to neutral condition.

5. The method for producing a nonvolatile thiazolidine compound according to any one of claims 2 to 4, wherein the reducing sugar is xylose or Z and glucose.

6. The method for producing a non-volatile thiazolidine compound according to claim 1, wherein the holding temperature of the cystine under heating is 25-100 ° C.

7. The method for producing a nonvolatile thiazolidine compound according to claim 6, wherein the holding temperature under heating is 60 to 90 ° C.

8. The method for producing a non-volatile thiazolidine compound according to claim 6 or 7, wherein the initial pH is carried out with a strong force.

9. The method for producing a nonvolatile thiazolidine compound according to any one of claims 6 to 8, wherein the reducing sugar is xylose or / and glucose.