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SOP: Catalase Test for Enzyme Activity in Dehydrated Vegetables

GIFSQ — Global Institute for Food Safety & Quality

Principle

Residual catalase in the dehydrated vegetable decomposes added hydrogen peroxide and liberates oxygen. Visible evolution of oxygen after the peroxide is added shows that the enzyme is still active — a positive test.

Apparatus required

  • Test tube (about 1 inch in diameter and 6 inches deep)

Reagents

a. Hydrogen peroxide solution, 3%.

Sample preparation

Break the dehydrated vegetable into small pieces. Do not use the ground sample-preparation procedure for this test.

Procedure

Fill the test tube to a depth of about 1 inch with small broken pieces of the dehydrated vegetable

↓

Cover the pieces with water and allow to stand for 10 min

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Add an equal volume of 3% hydrogen peroxide

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Mix the contents by shaking gently, and watch for evolution of oxygen

Interpretation

The test is positive if there is an evolution of oxygen.

Precautions

  • Add a volume of the peroxide equal to the volume of water covering the pieces.
  • Shake only gently; then look for gas evolution as the sign of a positive test.

References

Ranganna, S., Handbook of Analysis and Quality Control for Fruit and Vegetable Products, 2nd edition.

Standard Method for the Analysis and Examination of Foodstuffs, Commonwealth Food Specifications Committee, Department of Primary Industry, Canberra, 5th edn., p. 205, 1969 — cited in the book.