Red Seal Cook Practice Exam

What is the method to prevent vegetables from browning after being cut?

1. Applying salt to the cut surfaces

2. Applying an acid like lemon juice to the cut surfaces

3. Applying sugar to the cut surfaces

4. Applying vinegar to the cut surfaces

The correct answer is: Applying an acid like lemon juice to the cut surfaces

Applying an acid like lemon juice to the cut surfaces of vegetables is a well-known and effective method for preventing browning. When vegetables are cut, the cells are damaged, which triggers a reaction with oxygen in the air, leading to enzymatic browning. This process is primarily facilitated by an enzyme called polyphenol oxidase, which reacts with phenolic compounds in the presence of oxygen. Lemon juice, which contains citric acid, lowers the pH on the vegetable's surface. This acidic environment inhibits the activity of the polyphenol oxidase enzyme, thereby slowing down the browning reaction. Additionally, the presence of antioxidants in lemon juice can further help to protect the fresh appearance of the cut vegetables. While applying salt, sugar, or vinegar might have some effects on flavor or texture, they do not effectively inhibit the enzymatic browning process to the same extent as an acid like lemon juice.