GB/T 44738-2024 in English

1. Standard Overview

This standard GB/T 44738-2024 "Determination of Pectinase Activity for Feed" specifies the spectrophotometric determination method for pectinase activity in feed additives, which is applicable to the quantitative analysis of pectinase activity in solid and liquid samples. Its quantitative limit is 10 U/g (or U/mL), which is not applicable to alkaline pectinase.

2. Determination Principle

Pectinase catalyzes the decomposition of pectin to produce reducing sugars. After color development using 3,5-dinitrosalicylic acid (DNS) reagent, the color is compared by spectrophotometer at a wavelength of 540 nm, and the concentration of D-galacturonic acid is calculated to obtain the enzyme activity. This method is based on the linear relationship between the rate of enzymatic reaction and the amount of product generated.

3. Standard curve drawing

4. Reagents and instruments

5. Experimental steps

Preparation of sample solution: According to the sample type (solid or liquid), dilute to a concentration range suitable for colorimetric determination to ensure that the pectinase activity is between 1.29-1.94 U/mL.

Test blank determination: No sample solution is added, and the remaining steps are the same as the formal determination, which is used to correct the background absorbance.

Sample determination: Add appropriately diluted enzyme solution, keep warm at 37°C for 30 minutes, then color will develop, and the actual amount of reducing sugar produced can be obtained by colorimetry.