GB/T 36861-2018Determination of activity of beta-mannanase as feed additive—Spectrophotometric method (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

1 Scope

This standard specifies the spectrophotometric method for determining the activity of beta-mannanase in feed additives.

This standard applies to the feed additive beta-mannanase and its complex enzyme. The limit of quantitation of this method is 10 U/g.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this document. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 6682 Analytical laboratory water specifications and test methods

3 Terms and definitions

The following terms and definitions apply to this document.

4 Principle

Beta-mannanase degrades mannan into oligosaccharides and monosaccharides. Reducing oligosaccharides and monosaccharides occur in a boiling water bath with DNS reagents Color reaction. The color of the reaction liquid is proportional to the amount of reducing sugar produced by enzymatic hydrolysis, and the amount of reducing sugar is produced in the same amount as beta-mannose in the reaction solution.

The activity of the glycanase is directly proportional. The activity of the beta-mannanase was calculated by measuring the absorbance of the reaction solution by a spectrophotometer.

5 Reagents or materials

The reagents were of analytical grade unless otherwise stated.

5.1 Water. Meet the requirements of the secondary water in GB/T 6682.

5.2 Sodium hydroxide solution (200g/L). Weigh 20.0g of sodium hydroxide, dissolved in water, and dilute to 100mL.

5.3 Acetic acid solution (0.1mol/L). Take 0.60mL of glacial acetic acid, dilute with water, and dilute to 100mL.

5.4 Sodium acetate solution (0.1mol/L). 1.36g of sodium acetate trihydrate was weighed, dissolved in water, and made up to 100mL.

5.5 Acetic acid-sodium acetate buffer solution (0.1mol/L, pH5.5). Weigh 23.14g sodium acetate trihydrate, add 1.70mL glacial acetic acid, add Dissolve in water and dilute to 2000 mL. Determine the pH of the solution. If the pH deviates from 5.5, adjust with acetic acid solution (5.3) or sodium acetate solution (5.4) to 5.5.

5.6 3,5-dinitrosalicylic acid (DNS) reagent. weigh 3,5-dinitrosalicylic acid (chemically pure) 3.15g, add water 500mL, 45 ° C water bath Stir for 5s. Then slowly add 100mL sodium hydroxide solution (5.2), keep stirring until the solution is clear and transparent (adding sodium hydroxide) During the process, the temperature of the solution should not exceed 48 ° C). Then gradually add 91.00g of sodium potassium tartrate tetrahydrate, 2.50g of phenol and 2.50g of anhydrous […]