Chlorophyll Fixation

Chlorophyll is the green pigment found in plants. In cooking, chefs try to preserve the bright green colour of vegetables and herbs by controlling heat, time and acidity. The term “chlorophyll fixation” is sometimes used informally, but chlorophyll cannot be permanently fixed by blanching; the goal is to limit colour degradation during preparation and service.

Why green vegetables change colour

Chlorophyll can be altered by prolonged heating and acidic conditions, producing dull olive-green pigments such as pheophytin. Long cooking, acidic cooking liquids and extended hot holding can therefore make green vegetables lose their bright appearance.

How to preserve bright green colour

1. Use fresh, properly stored vegetables.
2. Bring a large volume of water to a vigorous boil.
3. Blanch vegetables in manageable batches for the shortest time needed to achieve the desired tenderness.
4. Transfer to an ice bath when rapid cooling is required.
5. Drain and dry thoroughly, then reheat or finish quickly for service.
6. Add acidic ingredients such as lemon juice or vinaigrette near the end when a bright green appearance is desired.

Why baking soda is not a good routine solution

Alkaline conditions can make green vegetables appear brighter by changing pigment chemistry, but baking soda can damage texture, flavour and some nutrients. It should not be used as a routine substitute for correct blanching and cooking control.

Chef’s tip: Blanching and shocking help preserve colour for later finishing, but the best result comes from using fresh vegetables and avoiding prolonged cooking or hot holding.

Key distinction: Chlorophyll preservation is about limiting pigment degradation; blanching does not permanently lock the green colour into a vegetable.