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Standard Solution Appendix
Name
Content
Definition
Description
Identification
Purity
Assay
Permitted Use Level
All
A. Synthetic Additives
B. Natural Additives
C. Mixture Additives
Standard and Specification > Synthetic Additives > Propylene Glycol Alginate
157. Propylene Glycol Alginate  
[Compositional Specifications of Propylene Glycol Alginate]
Description Propylene Glycol Alginate occurs as a white to yellowish~white coarse or fine powder. It is almost odorless. 
Identification To 1 g of Propylene Glycol Alginate. add 100 ml of water to produce a pasty solution. Use this solution as the test solution.

(1) To 5 ml of the test solution, add 5 ml of lead acetate solution. It immediately solidifies into a gelatinous state.

(2) To 10 ml of the test solution, add 1 ml of sodium hydroxide solution, heat in a water bath for 5~6 minutes, cool, and add I ml of diluted sulfuric acid. It immediately solidifies to a gelatinous state.

(3) To 1ml of the test solution, add 4 ml of water, and shake vigorously. Effervescence persists. 
Purity (1) Arsenic and Heavy Metals : Should follow the procedures in Purity (3) and (4) for [Sodium Alginate].

(2) Degree of Esterification : Esterification of Propylene Glycol Alginate is calculated by the following equation and its value should not  less than 75%.
    
               Degree of Esterification (%) = 100 - (a+b+c)
                      
   a, b, and c are obtained from (1), (2), and (3).
   A : content of free alginic acid (%)
   b : content of sodium alginate (%)
   c : content of insoluble ash (%)

(A) Free alginic acid : Weigh accurately about 0.5 g of Propylene Glycol Alginate (dried for 4 hours at 105°), dissolve in 200 ml of freshly boiled and cooled water, add 2 drops of phenolphthalein solution, and titrate with 0.02 N sodium hydroxide until the pink color persists for about 20 seconds. Calculate the content by the following formula. Perform a blank test in the same manner, and make any necessary correction.

  Content of free alginic acid (%)

         Volume of 0.02N sodium hydroxide consumed(ml)×0.00352
  = ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ x 100
                                Weight of the sample(g)

(B) Sodium alginate : Weigh accurately about 1 g of Propylene Glycol Alginate Alginate (dried for 4 hours at 105°) and follow the Procedure in Assay for alkaline salt of organic acid. I N this case, 20 ml of 0.1 N sulfuric acid and 0.1 N sodium hydroxide solution are used instead of 50 ml of 0.5 N sulfuric acid and 0.5 N sodium hydroxide solution. The content of sodium alginate is calculated by the following equation (indicator : 3 drops of methyl red solution).

Content of sodium alginate (%)
      
         Volume of 0.1N sulfuric acid consumed(ml)×0.0198
  =  ━━━━━━━━━━━━━━━━━━━━━━━━━━━ x 100
                              Weight of the sample(g)                  

(3) Insoluble ash : Dry the residue on the filter paper obtained in (B) of (1). ignite to constant weight, cool, and weigh accurately. Not more than 1.5%. 
Loss on Drying When Propylene Glycol Alginate is dried for 4 hours at 105°, the loss should not be more than 20%. 
Permitted Use Level of Propylene Glycol Alginate and Ingredients Containing it Usage should not be more than 1% of the food item as Propylene Glycol Alginate.