Green beans, snow beans, peas, asparagus: all these vegetables can lose their beautiful green colour when cooking, yet this natural phenomenon is avoidable by respecting a few simple instructions. And as Bonduelle knows a thing or two about cooking vegetables, here are our tricks to keep them dashing
A history of chlorophyll
These vegetables colour – and others – come from natural molecules called pigments, among which chlorophyll is responsible for the green colour. To keep it, beware of over-cooking: an over-stay in boiling water turns vegetables yellow which a rather sad-looking result in your plate.
To preserve, the ideal is to have a thermal shock. Indeed, plunging cooked vegetables in ice water allows to stop the cooking and “fix” chlorophyll’s properties. In the kitchen of professionals, this technique is called “British cooking”. This technique is the one used on a wider scale at Bonduelle for frozen vegetable production such as green beans.
In practice
For cooking green vegetables ideally (fresh or frozen):
- For a few minutes plunge them in a large uncovered pot of salted water. Follow the cooking time: for instance, asparagus and green are more enjoyable al dente!
- While they are cooking, prepare a salad bowl of cold water filled with ice – don’t skimp on the quantity: the greater the thermal shock the more preserved will be the colour.
- Drain the vegetables and plunge them immediately in iced water. Once they have cooled down, drain them again.
- The only thing left is to cook them, reheat them in a bit of butter or the oil of your choice, or add them in a salad. Be careful to pour the sauce at the last moment to avoid the vinegar or lemon juice "attacking" the chlorophyll and cancelling out all the British cooking effects.
What about bicarbonate?
Adding bicarbonate of soda in water also allows vegetables to keep their green colour. However, it has the inconvenient to makes them go a bit soft which is less enjoyable when eating.