JPS5932468B2 - Stabilizer for L-ascorbic acid - Google Patents

Description

[Detailed description of the invention] The present invention relates to a stabilizer for L-ascorbic acid.

L-ascorbic acid, or vitamin C, is one of the essential vitamins for living organisms, and is widely used in various foods and medicines primarily for the purpose of vitamin fortification, as well as as an antioxidant, freshness preservation agent, and coloring aid for meat. has been done.

Furthermore, it has recently been announced that ascorbic acid is effective in preventing colds and influenza, inhibiting the production of carcinogenic N-nitroso compounds, and treating cancer, and its usefulness is being reconsidered. On the other hand, the above-mentioned L-ascorbic acid is unstable in air and aqueous liquid, and especially in aqueous solution, it is destroyed extremely quickly (oxidative decomposition, etc.) by light, heat, or mixed heavy metal ions, so that its original effectiveness cannot be improved. It has a fatal flaw that cannot be expected. Conventionally, various stabilizers for stably preserving this L-ascorbic acid have been researched and developed, and metaphosphoric acid is known as one of the most excellent ones. However, the metaphosphoric acid
Phosphoric acids of various degrees of polymerization represented by the general formula (HP03)n, that is, ortho (P1), pyro (P2), tri (P3),
Tetra (P4), Penta (P5), Hexa (P6), Hepta (P7), Octane (P8), etc.
It is a mixture of long-chain (Pn) phosphoric acids, and according to the research of the present inventors, the mixing ratio of each phosphoric acid (P1 to Pn) component has a significant effect on the stabilizing effect of L-ascorbic acid. I found out that I can give it. However, the above-mentioned mixing ratio varies greatly due to slight changes in manufacturing conditions as well as the manufacturing method, and it is difficult to always obtain metaphosphoric acid with the same composition and with good reproducibility that can exhibit the desired stabilizing effect. It is extremely difficult. As described above, metaphosphoric acid has a variable effect on stabilizing ascorbic acid, is itself relatively unstable, is easily hydrolyzed in aqueous solution, and has a short chain length, ortho(P).
1) It has the disadvantage that it becomes phosphoric acid or pyro(P2) phosphoric acid, and the stabilizing effect of L-ascorbic acid decreases over time. In addition, condensed phosphates with excellent metal sequestering ability, such as sodium ultraphosphate and sodium hexametaphosphate, have been proposed as stabilizing agents other than the above-mentioned metaphosphoric acid; It is still low and there is room for practical improvement. The inventors
In view of the above-mentioned current situation, it is possible to exhibit a much superior L-ascorbic acid stabilizing effect compared to known stabilizers, and the effect is always constant and stable regardless of manufacturing conditions, and furthermore, Various studies have been conducted with the aim of providing a new stabilizer that can be guaranteed to be safe enough to be used as a food additive.

As a result, cyclic trimetaphosphate, which exhibits almost no metal sequestering ability, can surprisingly exhibit an extremely excellent stabilizing effect on L-ascorbic acid, becoming a stabilizer that meets the above objectives. I found out. The present invention was completed based on this knowledge. That is, the present invention relates to a stabilizer for L-ascorbic acid characterized by containing a cyclic trimetaphosphate as an active ingredient.

The stabilizer of the present invention has an extremely excellent stabilizing effect on L-ascorbic acid, which has not been found in conventional stabilizers of this kind, and can be used stably at high temperatures and under heavy metals, where L-ascorbic acid is most likely to be decomposed. It is characterized by its ability to exhibit its properties even in the presence of ions.

The reason why the stabilizer of the present invention can exhibit such excellent effects is currently not clear, but unlike other phosphates, cyclic trimetaphosphate, which is an active ingredient, usually contains L-ascorbic acid. Under acidic conditions such as those found in food products, L-ascorbic acid easily opens its ring and becomes a highly active radical, which reacts with L-ascorbic acid in some way to maintain the ascorbic acid in a stable state. It is thought that this is because of this. In any case, the above-mentioned cyclic trimetaphosphate has almost no metal ion sequestration effect (masking effect) as seen in condensed phosphates that have been proposed as this type of stabilizer, and therefore It is thought that L-ascorbic acid is stabilized by a completely different mechanism of action that cannot be expected from known stabilizers such as L-ascorbic acid. A typical example of the cyclic trimetaphosphate used as an active ingredient in the stabilizer of the present invention is cyclic sodium trimetaphosphate (Na3P3O9).

The compound has three forms namely type I (Na3P3O, -1
), types, and molds, and any of these forms can be equally effectively used in the present invention. In addition, the above Na3p3O
The anhydride represented by 9 can be dissolved in water and then recrystallized to form various hydrate crystals such as 1, 1.5, 3 and hexahydrates. For example, the above Na3p3O9
Form I, type or mold is dissolved in distilled water kept at about 60-70°C to make a saturated solution, filtered, and a small amount of alcohol is added to the distilled solution and left overnight in the refrigerator (below about 10°C). In particular, as a result of X-ray analysis, Na3p3O,.6H20
A white crystal that can be obtained can be obtained. These hydrates can also exhibit the stabilizing effect desired by the present invention, and can be used advantageously as well. Furthermore, the active ingredient compounds of the present invention include other alkali metal salts such as potassium salts in addition to the above-mentioned sodium salts of cyclic trimetaphosphoric acid. The above active ingredient compounds can be easily produced according to various methods. A typical manufacturing method for the above Na3p3O9 is as follows. That is, monosodium phosphate (NaH2PO4.2H
20, crystal) in a porcelain evaporating dish or crucible, about 50
It can be obtained as a white powder by heating at 0 to 530°C for about 3 hours, slowly cooling it, and then pulverizing it.
The heating time will vary depending on the amount of monosodium phosphate used, and the yield of Na3p3O9 will vary slightly depending on the atmosphere during heating (water vapor pressure), but under normal heating atmosphere there will be almost no change. It is not allowed. The above-mentioned Na3p3O9 can be obtained by pouring a phosphate such as NaH2PO4, sodium hexametaphosphate, or long-chain sodium phosphate into a platinum crucible, slowly melting it over a weak flame, and then heating the melt to about 1000°C. Form I can also be obtained by continuing melting in an electric furnace for about 3 to 5 hours and then cooling very slowly (usually taking about 20 hours to lower the temperature to about 50°C). In the above case, if the cooling rate is fast, an amorphous insoluble long-chain condensed phosphate is produced, making it difficult to obtain the target Na3p3O9. The fact that Na3p3O9 can be obtained as a single compound as described above is confirmed by X-ray analysis. Further, all of the cyclic trimetaphosphates used in the present invention are soluble in water,
Na3P3O9 (anhydride) has a melting point of 627.6°C, a density (d) of 2.476, a refractive index (n) of 1.478, and a solubility of 2.
17/Water 1007 properties are shown. The stabilizer for L-ascorbic acid of the present invention is basically prepared by using the above-mentioned cyclic trimetaphosphate alone or by blending it with appropriate additives as necessary in the form of a powder or an aqueous solution. Ru.

The additives that may be added as necessary include condensed phosphates and orthophosphates such as tripolyphosphate, pyrophosphate, hexaphosphate, and ultraphosphate, and organic acids such as citric acid, tartaric acid, and malic acid. Examples include acids and salts thereof. When using the stabilizer of the present invention, it is necessary to
- It may be added and mixed to ascorbic acid itself or products containing the ascorbic acid, such as foods such as fruit juices and canned fruits, medicines, etc.

The amount of stabilizer to be used can be determined as appropriate depending on the type of product to which it is added and mixed, but usually in fruit juices, L-ascorbic acid is up to about 0.1%, that is, 1f/
The active ingredient compound is about 0.08 to 107/f in terms of concentration of phosphorus! It is preferable to set it as the range of. In this way, the L-ascorbic acid stabilized by the stabilizer of the present invention retains its original vitamin-enhancing effects over a long period of time, and is therefore suitable for its usual uses, such as fruit juices, canned fruits, jams, etc. It can be used extremely effectively in confectionery such as drops and powdered juices, dairy products, soft drinks, beer, marcarin, etc., and pharmaceuticals, as well as foods that are subject to heating, etc., for which the use of L-ascorbic acid was traditionally inappropriate. It will also be available for use. Experimental examples for clarifying the effects of the stabilizer of the present invention are listed below.

Experimental Example 1 Ascorbic acid was determined as follows in accordance with the Japanese Pharmacopoeia (9th edition), and the stability test over time of the aqueous solution was conducted.

(1) Ascorbic acid Commercially available special grade L-ascorbic acid is used.

(2) Preparation of 2,6-dichlorophenol indophenol sodium reagent for titration NaHCO3O. Add 50 ml of water to O42y and dissolve, further dissolve 0.057 ml of 2,6-dichlorophenol indophenol sodium, add water to make a total volume of 200 ml, and filter.

Prepare immediately before use. (3) Standardized ascorbic acid standard product in a silica gel desiccator,
Dry for 4 hours, then accurately weigh out about 0.05y, add metaphosphoric acid/acetic acid test solution and dissolve it to make exactly 100ml, then accurately weigh out 2d, and add metaphosphoric acid/acetic acid test solution 8T1.
1, shake, and titrate with phenol sodium reagent under 2,6-dichlorophenol for titration until it exhibits a pale pink color that lasts for 5 seconds.

Perform a blank test in the same way, correct the above titration value, and use 1 m of this reagent.
Amount A of L-ascorbic acid (C6H8O6) per 1
Calculate 7rl9. 1 ml of 2,6-dichlorophenol indophenol sodium reagent used in this experiment was
It was 0.1ηC6H8O6.

) Preparation of metaphosphoric acid/acetic acid test solution Add water to 157 metaphosphoric acid and 40 ml of glacial acetic acid and dissolve to make 500 ml.

Store in a cool place. Use the test solution within 2 days of preparation. The phosphorus concentration in this test solution is 4.7t/500WLI as the result P of the colorimetric analysis described in (6) below. )) Preparation of test solution Accurately weigh 0.25 to 0.57 of commercially available special grade L-ascorbic acid, add it to the following aqueous solutions of phosphates or metaphosphoric acid/acetic acid solutions, dissolve, and add distilled water. Add
The total volume is 500ml.

The phosphorus concentration (P) in each sample solution is 4.77/500ml
and keep it constant. As a control, a solution of L-ascorbic acid dissolved in distilled water was prepared. Test solution> (T) Additive solution of cyclic sodium trimetaphosphate (Na3P3O9, product of the present invention) Na3p3O9 obtained in Production Example 1 described later was used.

([[) Cyclic sodium tetrametaphosphate (Na4P4
OL2) Additive solution Hydrolyze diphosphorus pentoxide (P2O5) 507 in 300111 ice water, neutralize this hydrolysis product to pH 7 using concentrated caustic soda solution, and precipitate by adding a small amount of ethanol to this. Na4p4Ol2・4H2
Uses 0 crystals.

Ultra Sodium Phosphate Additive Liquid Food additive "Ultrapolis" (manufactured by Mihejima Chemical Industry Co., Ltd., white powder,
PHL of 1% solution. 7-1.9, P2O5 content 76-8
0%) is used.

(IV) Sodium hexametaphosphate (Graham salt) additive liquid Food additive "Sodium metaphosphate" (manufactured by Dodosha,
White powder, 1% solution pH 642-6.8, P2O5 content 66-70%) was used.

V Sodium tripolyphosphate (Na5P3OlO) additive liquid Food additive "sodium polyphosphate" (manufactured by Rin Kagaku Kogyo Co., Ltd., white powder, 1% solution, pH 9.2-9.8
, P2O5 content 56-58%).

(V[) Sodium monohydrogen phosphate (Na2HPO4・1
2H20) Additive liquid food additive "disodium phosphate (crystal)" (manufactured by Miheijima Chemical Industry Co., Ltd., colorless to white crystal, PH of 1% solution
9. 0~9.4, purity 98.0~100%).

(MI) Sodium acid pyrophosphate (Na2H2P2O7) additive liquid Food additive "Sodium acid pyrophosphate" (manufactured by Rin Kagaku Kogyo Co., Ltd., white crystalline powder, 1% solution pH 4.5 ~
5.0, P2O5 content 60-65%).

() Metaphosphoric acid/acetic acid solution Use the same solution as the metaphosphoric acid/acetic acid test solution prepared in (4) above.

Control solution (using distilled water) (6) Determination of phosphorus Absorption photometry with phosphomolybdenum blue is used.

The molybdenum test solution used was prepared by dissolving special grade ammonium molybdate [(NH4)6M07024.4H20] 357 in 200111 distilled water, and adding 200ml of concentrated hydrochloric acid to it.
As 1 is added, a white precipitate initially forms, but gradually dissolves. Add 3y of metallic zinc to this, and then, while stirring well, add 200ml of concentrated hydrochloric acid and 40ml of concentrated sulfuric acid cooled in advance on ice.
Add 0ml and make the total volume to 1000ml with distilled water. The test solution thus obtained is a clear blue-green solution. Add 2 ml of this test solution to the sample solution containing phosphorus, and add about 5 ml of distilled water.
After stirring thoroughly, the mixture was heated in a 95°C delta bath for 1 hour, and after cooling, the total volume was made up to 25 ml with distilled water. Absorbance is 83
Measurement was performed using a Hitachi spectrophotometer model 100-20 using a wavelength of 0 nm. (7) L-ascorbic acid stability test Each test solution prepared according to (5) above was left at room temperature,
After a predetermined number of days have elapsed since the test solution preparation, take 2 ml of each solution and measure the residual amount of L-ascorbic acid (t) according to (3) above.
) is determined, and the stability of L-ascorbic acid over time is examined as a percentage of the initial amount of L-ascorbic acid ('Ii).

The results are shown in Figure 1. In FIG. 1, the vertical axis shows the L-ascorbic acid residual rate (%), and the horizontal axis shows the number of elapsed days (days).

1 to 1 in the figure represent each sample solution (1) to (e) described in (6) above.
corresponds to As is clear from Figure 1, in the solution using the stabilizer of the present invention (test solution 1), the L-ascorbic acid residual rate remained at approximately 80% even after 28 days (4 weeks). , it can be seen that the stabilizer significantly improves the stability of L-ascorbic acid.

On the other hand, the solution using metaphosphoric acid (test solution), which is known as the best so far, only had a residual rate of about 60% after 28 days, and the residual rate was only about 60% after 28 days. It can be seen that the residual rate of the sample solution after 28 days was less than 50%. Next, using each of the above test solutions and various other commercially available phosphates, X. The solution prepared by Mr. Ishikawa (both have a phosphorus concentration of P-4.77/500m)
1) was subjected to the same test, and the ascorbic acid residual rate (%) after 21 days (3 weeks) was determined in the same manner. The results are shown in Table 1 below.

It is clear from Table 1 above that the stabilizer of the present invention can exhibit an excellent stabilizing effect on L-ascorbic acid, unlike other phosphates and phosphoric acid.

Experimental Example 2 The same procedure as in Experimental Example 1 was carried out except that each test solution was left under a high temperature condition of 70° C. after preparation.

The results are shown in Figure 2. As is clear from FIG. 2, the stabilizer of the present invention using cyclic sodium trimetaphosphate has a greater stabilizing effect on L-ascorbic acid even at high temperatures than metaphosphoric acid.

Experimental Example 3 In Experimental Example 1, 100p of Sn2+ ions were added to each sample solution.
A similar test was conducted in the presence of pm.

The results are shown in Figure 3. Figure 3 shows that ascorbic acid is rapidly decomposed in distilled water due to the presence of Sn2+ ions, but when the stabilizer of the present invention is used, the above decomposition is extremely suppressed and the stability is significantly improved. I understand.

Such an effect cannot be expected with metaphosphoric acid or sodium acid pyrophosphate. Examples of the production of cyclic trimetaphosphate, which is the active ingredient compound of the stabilizer of the present invention, will be given below.

Production Example 1 Anhydrous monosodium phosphate (special grade reagent) 10007 is weighed in a crucible (evaporating dish) and heated in an electric furnace at a temperature of 530±5°C (mercury thermometer) for 3 hours.

It is slowly cooled and then crushed to obtain cyclic sodium trimetaphosphate (Na3P3O9) 9007. X-ray analysis shows that the obtained Na3p3O9 has a type I crystal structure. The X-ray diffraction diagram is shown in FIG. In the figure, the vertical axis shows the X-ray diffraction intensity, and the horizontal axis shows the diffraction angle (2θ).
The measurement conditions in this figure are as follows. Production Example 2 90y of the white powder of Na3P3O9 (Type I) produced in Production Example 1 above was added to 500ml of distilled water heated to about 60°C, dissolved, and filtered to remove undissolved residue. 1 liquid
Cool to below 0°C, add 200 ml of ethanol little by little to precipitate crystals, and filter by absorption.

The white crystals thus obtained were prepared using the same X as in Production Example 1 above.
As a result of the ray analysis, the X-ray diffraction diagram shown in FIG. 5 was obtained, and it was recognized from this diagram that it was Na3p3O9.6H20.

[Brief explanation of the drawing]

Figures 1 to 3 are graphs showing changes over time in the residual rate (%) of L-ascorbic acid in various solutions.
The figure shows the results under room temperature, FIG. 2 shows the results under a temperature condition of 70° C., and FIG. 3 shows the results under the coexistence of Sn2+ ions.

Claims (1)

[Claims] 1. A stabilizer for L-ascorbic acid, characterized by containing cyclic trimetaphosphate as an active ingredient.