Identification test
UV absorbance: A 1/50000 sample solution was prepared with 0.01 mol/L hydrochloric acid solution, which had a maximum absorbance at a wavelength of 256 nm ± 2 nm. A250/A260 ratio is at the range of 0.95 to 1.03, and A280/A260 ratio is at the range of 0.63 to 0.71.
Ribose test exhibits positive result. Take 3 mL of 0.03% sample solution, add 0.2 mL of the ethanol solution of 10% dihydroxy toluene, and 3 mL 0.1% ammonium ferric sulfate hydrochloric acid (TS-100), heat in water bath for 10 min, the color of the solution should be green.
Organic phosphate test is positive. Take 5 mL of 1% sample solution plus 2 mL of magnesium oxide mixture solution (TS-133), there should be no precipitation occurred. Further add 7 mL of nitric acid and boil for 10min, neutralize with sodium hydroxide solution (TS-224) and should exhibit phosphate reaction (IT-26).
The sodium salt test was positive (IT-28).
Solubility: it is soluble in water, slightly soluble in ethanol but almost insoluble in acetone and ether (OT-42).
Content analysis
Accurately weigh 500 mg of sample and dissolve with 0.01 mol/L hydrochloric acid, and add the volume up to 1000 ml. Take 10 mL of this solution, and then add 0.01mol/L hydrochloric acid to a final volume of 250 ml and mix. Use 0.01mol/L hydrochloric acid as a control, place it in 1 cm cuvette and measure the absorbance A under the wavelength of 260nm and then calculated as follows:
Amount (%) = A/289.8 × 250,000/Sample amount (mg) × 100/(100-Moisture (%)) × 100
Toxicity
ADI is not subject to special provision (FAO/WHO, 2001).
LD50:10 mg/kg (rat, oral). After chronic test feeding of 0.1% to 1% feed for 6 months, weight and tissue get no abnormal changes.
It can be safely used in food products (FDA, §172.530, 2000).
EEC-HACSG provides that it should not be used for infant food.
Usage limit
GB 2760-96: all kinds of food, take GMP limit.
FAO WHO: luncheon meat, ham, bacon, etc., 500 mg kg (in guanosine), broth and soup, GMP.
Standard for Maximum Allowable amount and maximal allowable residue of Food Additives
Name of additive Food allowed to use it as additive Function of additive Maximal allowable amount（g/kg） Maximal allowable amount（g/kg）
5'-guanylate disodium Food Food purpose flavor The perfume ingredients used in formulating fragrances shall not exceed the maximal allowable amount documented in GB 2760
5'-guanylate disodium Food Flavoring agent Apply appropriate amount based on the demand of production except in cases where there is specific rule
Chemical properties
It appears as colorless to white crystalline or crystalline powder, usually containing 7 molecules of crystal water, being odorless, having unique flavor similar to mushrooms. Melting point is not obvious. It undergoes browning under 240 ℃ and decomposition under 250 ℃. It is stable against acid, alkali, salt and heat. It has strong moisture absorption property and is easily soluble in water (25 ℃, 25%). The pH value of its 5% aqueous solution is 7.0 to 8.5, being slightly soluble in ethanol, acetone and ether. Mouse: oral LD50: 10g/kg, ADI does not require special rule(FAO/WHO, 1994).
Uses
Guanylate sodium is allowed flavoring agent allowed at home and abroad, often used together with MSG and sodium inosinate. When mixed for usage, it has multiplication effect on the taste. It can be used for all types of food and should be subject to appropriate use according to production needs.
It is mainly used as condiments, being a new generation food by freshener.
It is a kind of flavor agent with mushrooms flavor. It is often used in conjunction with sodium glutamate (adding amount is 1%~5%), there is a very significant increase in freshener effect.
Preparation
The production methods of guanylic acid mainly include enzymatic hydrolysis and fermentation method. In the fermentation method, there are two-step method and combination method with biosynthesis and chemical synthesis, two kinds which are of industrial significance.
(1) Ribonucleic acid (RNA) hydrolysis method. See the production method of 5'-inosinic acid disodium.
(2) Two-step method. Take glucose as the carbon source and ferment with the Bacillus subtilis mutant to obtain the guanosine. The production level was 10.5 g/L. Then guanosine, in pyridine solution, is acidified with phosphorus oxychloride phosphate to obtain guanylate.
(3) Biosynthesis and chemical synthesis.
At pH=7, apply Bacillus megaterium (No. 336) for fermentation of glucose (8%) for 90 h at pH = 7, producing 15 g/L 5-amino-4-carboxamide nucleoside (AICAr); then extract by ion exchange, followed by concentration and drying to be dissolved in methanol containing NaOH. Add carbon disulfide for co-heating so that it is converted into 2-thioglycoside; It is finally oxidized with hydrogen peroxide; add excess ammonia and heat to obtain guanosine which is further converted to guanylate through phosphorylation.
Chemical Properties
Disodium guanylate contains approximately seven molecules of water of crystallization. It has a characteristic taste.
Disodium guanylate (GMP) is often used in combination with disodium inosinate (IMP) and monosodium glutamate (MSG). These
substances are some of the taste principle components in both animal and vegetable foods, and they contribute to a?fundamental?taste?sensation?called?“savory.” The taste intensity differs with the concentration. Although taste quality of IMP or GMP in the
presence of MSG is almost similar, GMP provides smoother “fullness” and “thickness” than IMP.
The synergistic effect between nucleotides and MSG in cooking has long been empirically established. For example, in traditional
Japanese cooking, soup stocks are made by simmering dried tangle (kombu), rich in glutamate (2.26 to 5.73 g/100 g), along with
dried bonito (katsuobishi), rich in IMP (0.63 to 1.31 g/100 g) or with a type of dried mushroom, (shiitake) rich in GMP (0.21 g/100 g).
Europeans make soup stocks by cooking animal meats rich in IMP or several kinds of mushrooms rich in GMP, along with vegetables
containing glutamate (Burdock, 1997)
Chemical Properties
White crystalline powder
Occurrence
Reported found in mushroom (shiitake, enokidake, matsutake, syoro, hatsutake), pork, chicken and whale
Uses
These Secondary Standards are qualified as Certified Reference Materials. These are suitable for use in several analytical applications including but not limited to pharma release testing, pharma method development for qualitative and quantitative analyses, food and beverage quality control testing, and other calibration requirements.
Uses
Guanosine 5'-monophosphate disodium salt is a flavor enhancer which is a crystalline powder, colorless or white, and has characteristic taste. It is soluble in water, sparingly soluble in alcohol, and practically insoluble in ether. It is obtained by chemical synthesis. It is also termed sodium 5-guanylate and disodium guanosine-5-monophosphate.
Uses
Flavor potentiator in foods.Sodium Guanylate is a salt replacement flavor enhancer. Food additive.
Definition
ChEBI: An organic sodium salt that is the disodium salt of GMP.
Preparation
This flavor enhancer is derived from fungal sources.
Taste threshold values
0.0125 g/dL (in water)
General Description
Pharmaceutical secondary standards for application in quality control, provide pharma laboratories and manufacturers with a convenient and cost-effective alternative to the preparation of in-house working standards. Disodium Guanylate is a flavor enhancer, obtained via chemical synthesis. It is used in combination with monosodium glutamate and disodium inosinate and helps in contributing to a fundamental taste sensation called savory in both animal and vegetable foods.
Biochem/physiol Actions
Guanosine 5′-monophosphate (GMP) is a ribonucleoside monophospate which upon phosphorylation to GTP becomes incorporated into ribonucleic acids (RNAs) by various RNA polymerase(s). Guanosine-5′-monophosphate (GMP) can be used to study modulation of glutamatergic neurotransmission.
