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National Food Safety Standard
Food Additive – Disodium 5’-guanylate
1 Scope
This standard is applicable to the food additive, disodium 5’-guanylate, obtained by fermentation method or enzyme hydrolysis method with starch and saccharide as raw materials.
2 Chemical Name, Structural Formula, Molecular Formula and Relative Molecular Mass
2.1 Chemical name
Disodium 5’-guanylate
2.2 Structural formula
2.3 Structural formula
C10H12N5Na2O8P·nH2O
2.4 Relative molecular mass
407.18 (as per 2011 international relative atomic mass, calculated as water-free)
3 Technical Requirements
3.1 Sensory requirements
Sensory requirements shall be in accordance with those specified in Table 1.
Table 1 Sensory Requirements
Item Requirement Inspection method
Color and lustre Colorless or white Put a proper amount of specimen into a clean and dry white porcelain dish, and observe its color and lustre as well as state under natural light.
State Crystal or crystalline powder
3.2 Physical and chemical indexes
Physical and chemical indexes shall be in accordance with those specified in Table 2.
Table 2 Physical and Chemical Indexes
Item Index Inspection method
Content of disodium 5’-guanylate (calculated by dry basis), ω/% 97.0~102.0 A.2 of Annex A
Ultraviolet absorbance ratio (250/260) 0.95~1.03 A.2 of Annex A
(280/260) 0.63~0.71
Loss on drying, ω/% ≤ 25.0 Direct drying method in GB 5009.3 a
Luminous transmittance (5% aqueous solution)/% ≥ 95.0 A.3 of Annex A
pH(5% aqueous solution) 7.0~8.5 A.4 of Annex A
Other nucleotides Pass the test A.5 of Annex A
Amino acid Pass the test A.6 of Annex A
Ammonium salt Pass the test A.7 of Annex A
Arsenic (As)/(mg/kg) ≤ 2.0 GB 5009.76
Heavy metal (calculated by Pb)/(mg/kg) ≤ 20 GB 5009.74
a Weigh 1g (to the nearest 0.000 1g) of specimen at drying temperature 120℃ and drying duration of 4h.
Annex A
Inspection Methods
A.1 General requirements
Unless otherwise specified, analytically pure reagents and Grade 3 water (specified in GB/T 6682) shall be used in this standard; if there is no requirement, standard solution, standard solution for impurity determination, preparations and products used in test shall be prepared according to those specified in GB/T 601, GB/T 602 and GB/T 603. Solutions used in the test are all aqueous solution, unless other solvents are indicated to be used for preparation.
A.2 Determination of disodium 5’-guanylate content (calculated by dry basis) and ultraviolet absorbance ratio
A.2.1 Reagent
Hydrochloric acid solution: measure 0.9mL of hydrochloric acid and slowly inject it into 1 000mL of water.
A.2.2 Apparatus
Ultraviolet spectrophotometer.
A.2.3 Analytical procedures
A.2.3.1 Preparation of specimen solution
Weigh 0.5g (to the nearest 0.000 1g) of specimen, dissolve it with a proper amount of hydrochloric acid solution to 1 000mL and shake well. Pipet 10mL of the above solution, dilute it with hydrochloric acid solution to 250mL and shake well to serve as specimen solution for future use.
A.2.3.2 Determination
Inject the specimen solution into 1cm quartz cuvette, measure the absorbance at 250nm, 260nm, and 280nm with ultraviolet spectrophotometer by taking hydrochloric acid solution as reference solution.
A.2.4 Result calculation
A.2.4.1 Calculation of disodium 5’-guanylate content (calculated by dry basis)
The mass fraction ω1 of disodium 5’-guanylate content (calculated by dry basis) is calculated according to Formula (A.1):
1 Scope
2 Chemical Name, Structural Formula, Molecular Formula and Relative Molecular Mass
3 Technical Requirements
Annex A Inspection Methods
