National food safety standard- Determination of phytic acid in foods
1 Scope
This standard specifies the method for determination of phytic acid in foods.
This standard is applicable to the determination of phytic acid in edible greases, processed fruits, meat products, fresh shrimps, candies, and fruit and vegetable drinks.
2 Principle
The specimen is extracted with acidic solution, adsorbed and desorbed by anion exchange resin, and the phytic acid in the eluate undergoes a fading reaction with the mixed solution of ferric chloride-sulfosalicylic acid. The absorbance is measured at a wavelength of 500nm with a spectrophotometer to calculate the phytic acid content in the specimen.
3 Reagents and materials
Unless otherwise specified, only analytically pure reagents and Grade 3 water specified in GB/T 6682 are used for the purpose of this method.
3.1 Reagents
3.1.1 Sodium hydroxide.
3.1.2 Sodium chloride.
3.1.3 Ferric chloride.
3.1.4 Hydrochloric acid.
3.1.5 Sulfosalicylic acid.
3.2 Preparation of reagents
3.2.1 30g/L sodium hydroxide solution: Weigh 30g sodium hydroxide, dissolve it with water, and then dilute with water to 1,000mL.
3.2.2 0.7mol/L sodium chloride solution: Weigh 40.91g sodium chloride, dissolve it with water, and then dilute with water to 1,000mL.
3.2.3 0.05mol/L sodium chloride solution: Weigh 2.92g sodium chloride, dissolve it with water, and then dilute with water to 1,000mL.
3.2.4 1.2% hydrochloric acid solution: Measure 33.3mL hydrochloric acid, and dissolve it with 966.7mL water.
3.2.5 Sodium sulfate-hydrochloric acid extraction solution: Weigh 100g anhydrous sodium sulfate, dissolve it with 1.2% hydrochloric acid solution, and then dilute with 1.2% hydrochloric acid solution to 1,000mL.
3.2.6 Ferric chloride-sulfosalicylic acid reaction solution: Weigh 1.5g ferric chloride and 15g sulfosalicylic acid, dissolve it with water, and then dilute with water to 500mL. Before use, dilute it with water by a multiple of 15.
Foreword i
1 Scope
2 Principle
3 Reagents and materials
4 Instruments and apparatus
5 Preparation and preservation of specimen
6 Analytical procedures
7 Analytical procedures
8 Expression of analysis results
9 Precision
10 Others
