Authorization for Use as Food Additive ( trans -2-Pentenal and Magnesium 
Monohydrogen Phosphate)  
 
The government of Japan is to designate trans -2-Pentenal and Magnesium 
Monohydrogen Phosphate as authorized food additive.  
 
Summary  
Under Article 10 of the Food Sanitation Law, food additives shall not be used marketed 
without the authorization by the Minister of Health, Labour and Welfare. Where 
standards for use of additives and/or their compositional specifications are established 
based on Article 11 of the law, those additives that do not compliant with these 
standards and/or specifications shall not be used or marketed.   
 
In response to a request from the Minister of Health, Labour and Welfare, the 
Committee on Food Additives of the Food Sanitation Council which is established under 
the Pharmaceutical Affairs and Food Sanitation Council has discussed the adequacy of 
the designation of trans -2-Pentenal and Magnesium Monohydrogen Phosphate as food 
additive. The conclusion of the committee is outlined below.  
 
 
 
Outline of conclusion  
The Minister of Health, Labour and Welfare, based on Article 10 of the Food Sanitation 
Law, should designate trans -2-Pentenal and Magnesium Monohydrogen Phosphate, as 
food additive unlikely to harm human health, and establish compositional specifications 
and other necessary standards for these substances, based on Article 11 of the law (see 
Attachments 1 and 2).  
 
  Attachment 1 
 
trans -2-Pentenal 
(E )-2-Pentenal 
 
Standard for use  
It shall not be used for purposes other than flavoring.   
 
Compositional specifications  
Substance name   
trans -2-Pentenal 
Structural formula 
 H3C CHO
 
                      
Molecular formula   C 5H8O 
Mol. Weight   84.12 
Chemical name [CAS number]   (2E )-Pent-2-enal [1576-87-0] 
Content  trans -2-Pentenal contains not less than 95.0% of trans -2-pentenal (C 5H8O).  
Description   trans -2-Pentenal occurs as a colorless to light yellow, transparent liquid 
having a characteristic odor.     
Identification Determine the infrared absorption spectrum of trans -2-Pentenal as 
directed in the Liquid Film Method under Infrared Spectrophotometry, and compare it 
with the Reference Spectrum. Both spectra exhibit absorptions having about the same 
intensity at the same wavenumbers.   
Purity   (1) Refractive index   n21
D: 1.440–1.457. 
(2) Specific gravity   d21
21: 0.850–0.858. 
(3) Acid value   Not more than 6.0 (Flavor Substance Tests).  
Assay  Proceed as directed in the Peak Area Percentage Method in the Gas 
Chromatographic Assay under the Flavor Substance Tests. Use operating conditions (2). 
Determine the peak area percentage of the component to be determined by normalizing 
the sum of the peak areas of all components that appear within 60 minutes after 
injection as 100. Use the following operating conditions.  Column: Use a silicate-glass capillary tube (0.25–0.53 mm in internal diameter and 
50–60 m in length) coated with a 0.25–1 mm thick layer of polyethylene glycol for gas 
chromatography.   
Column temperature: Maintain the temperature for 5 minutes at 50 °C, raise to 
230°C at a rate of 5 °C/minute, and maintain for 19 minutes.  
Flow rate: Adjust so that the peak of the component to be determined appears between 
5–20 minutes after injection.  
 
 
  IR Spectrum  
  
trans -2-Pentenal Attachment 2 
 
 
Magnesium Monohydrogen Phosphate 
 
 
Compositional specifications  
Substance name   Magnesium Monohydrogen Phosphate       
Molecular formula   MgHPO 4・3H 2O    
Mol. Weight   174.33 
Chemical name [CAS number]    
Magnesium monohydroge n phosphate trihydrate [7782-75-4] 
Content  Magnesium Monohydrogen Phosphate, when ignited, contains not less than 
96.0% of magnesium monohydrogen phosphate (Mg 2P2O7). 
Description   Magnesium Monohydrogen Phosphate occurs as a white crystallized 
powder.     
Identification    
(1) To 0.1 g of Magnesium Monohydrogen Phosphate, add 0.5ml of dilute acetic acid 
and 20 ml of water, and then add 1 ml of iron(III) chloride TS. Allow to stand for 5 
minutes, and filter. The filtrate responds to all tests for Magnesium Salt in the 
Qualitative Tests.    
(2) A solution of 0.2 g of Magnesium Monohydrogen Phosphate in 10 ml of dilute 
nitric acid produces a yellow precipitate, when ammonium molybdate TS is added 
dropwise. The resulting precipitate dissolves on the addition of ammonia TS.    
Purity   (1) Fluoride   Not more than 25 mg/g as F. 
Test Solution  Weigh 0.20 g of Magnesium Monohydrogen Phosphate, transfer into 
a beaker, and dissolve in 10 ml of diluted hydrochloric acid (1 in 10). Boil the resulting 
solution for 1 minute, transfer into a polyethylene beaker, and immediately cool with ice. 
Add 15 ml of sodium citrate (1 in 4) and 10 ml of a solution of disodium 
ethylenediaminetetraacetic acid (1 in 40), and mix. Adjust the pH of the solution to 
5.4–5.6 with diluted hydrochloric acid (1 in 10) or sodium hydroxide solution (2 in 5). 
Transfer this solution into a 100 ­ml volumetric flask, and dilute with water to volume. 
Place about 50 ml of this solution in a polyethylene beaker. Use as the test solution.             
Control Stock Solution  Weigh 2.210 g of sodium fluoride, previously dried at 110 ˚C 
for 2 hours, transfer into a polyethylene beaker, add 200 ml of water, and dissolve while stirring. Transfer this solution into a 1000-ml volumetric flask, dilute with water to 
volume, and then transfer into a polyethylene container.  
Control Solution   Transfer exactly 5 ml of the control stock solution into a 1000-ml 
volumetric flask, and add water to volume. Transfer exactly 1 ml of this solution into a 
polyethylene beaker, add 15 ml of sodium citrate solution (1 in 4) and 10 ml of a solution 
of disodium ethylenediaminetetraacetate (1 in 40), and mix. Adjust the pH of the 
resulting solution to 5.4–5.6 with diluted hydrochloric acid (1 in 10) or sodium 
hydroxide solution (2 in 5). Transfer this solution into a 100-ml volumetric flask, and 
add water to volume. Place about 50 ml of the solution into a polyethylene beaker. Use 
this solution as the control solution.  
Procedure  Measure the electric potentials of both solutions, using a potentiometer 
connected to a reference electrode and a fluorine ion electrode. The electric potential of 
the test solution is not lower than that of the control solution.  
(2) Lead   Not more than 4.0 mg/g as Pb. 
Test Solution  Weigh 2.5 g of Magnesium Monohydrogen Phosphate, and transfer 
into a 200-ml beaker. Add 40 ml of diluted hydrochloric acid (12 in 25) to dissolve it, 
cover the beaker with a watch glass, boil for 5 minutes, and cool. Use the resulting 
solution as the sample solution. To the sample solution, add 10 ml of a solution of 
diammonium hydrogen citrate (1 in 2), and make weakly alkaline with ammonia 
solution using thymol blue TS as the indicator. The precipitate is formed. After cooling, 
transfer the solution into a 200-ml separating funnel, wash the precipitate in the beaker 
with water, and add the washings to the funnel to make about 100 ml. Add 5 ml of a 
solution of ammonium pyrrolidine dithiocarbamate (3 in 100), and allow to stand for 5 
minutes. Shake for 5 minutes with 10 ml of butyl acetate, and allow to stand. Use the 
butyl acetate layer as the test solution.  
Control Solution   Measure exactly 1 ml of Lead Standard Solution, and add water 
to make exactly 100 ml. Measure exactly 10 ml of this solution, and proceed as directed 
for the sample solution.  
Procedure   Proceed as directed in Method 1 in the Lead Limit Test. 
(3) Arsenic   Not more than 4.0 mg/g as As 2O3. 
Test Solution   Dissolve 0.50 g of Magnesium Monohydrogen Phosphate in 5 ml of 
dilute hydrochloric acid.  
Apparatus    Use Apparatus B.  
Loss on Ignition  29−36% (800 ± 25ºC, 3 hours). 
Assay   Weigh accurately about 0.5 g of Magnesium Monohydrogen Phosphate, 
previously ignited, add 50 ml of water and 2 ml of hydrochloric acid, and dissolve by heating. After cooling, make exactly 100 ml with water. Transfer 50 ml of this solution 
into a beaker, add 100 ml of water, and heat to 55 −60ºC. Add 15 ml of 0.1 mol/L EDTA 
using a buret, and adjust its pH to 10 with sodium hydroxide TS while agitating using a 
magnetic stirrer. Add 10 ml of ammonium chloride buffer solution, and titrate with 0.1 
mol/L EDTA (indicator: eriochrome black T TS). The endpoint is when the color of the 
solution changes to blue.  
Each ml of 0.1 mol/L EDTA = 22.26 mg Mg 2P2O7