GB 5009.303-2025 National food safety standard - Determination of yeast β-glucan in foods
1 Scope
This standard specifies the method for determination of insoluble yeast β-glucan in foods.
This standard is applicable to the determination of insoluble yeast β-glucan in milk and milk products, protein powder, candies, and beverages.
2 Principle
After the specimen is freed of fat and protein by protease and/or lipase, yeast β-glucan is precipitated by centrifugation. The precipitated yeast β-glucan is hydrolyzed into glucose under the action of multiple enzymes. Glucose oxidase (GOD) is used to catalyze the oxidation of glucose under aerobic conditions to generate D-glucuronic acid-d-lactone and hydrogen peroxide, hydrogen peroxide is catalyzed by peroxidase (POD) to react with 4-aminoantipyrine and p-hydroxybenzoic acid to generate red quinone imine (GODPOD method). The absorbance of quinone imine is measured at a wavelength of 510 nm using a spectrophotometer. Finally, the content of yeast β-glucan in the sample is calculated by the conversion factor of yeast β-glucan and glucose (0.9).
3 Reagents and materials
Unless otherwise specified, analytically-pure reagents and Grade III water (defined in GB/T 6682) are adopted for the purpose of this method.
3.1 Reagents
3.1.1 Alkaline protease, liquid, enzyme activity ≥ 240 000 U/mL.
3.1.2 Neutral protease, liquid, enzyme activity ≥ 80 000 U/mL.
3.1.3 Acidic protease, liquid, enzyme activity ≥ 50 000 U/mL.
3.1.4 Lipase, liquid, enzyme activity ≥ 20 000 U/mL.
3.1.5 Tetrasodium ethylenediaminetetraacetic acid dihydrate (C10H12N2Na4O8·2H2O).
3.1.6 Tris(hydroxymethyl)aminomethane (C4H11NO3).
Contents
1 Scope
2 Principle
3 Reagents and materials
4 Apparatus and equipment
5 Preparation of specimens
6 Analysis procedures
7 Expression of analysis results
8 Precision
9 Others
