HOW CHLOROPHYLL KEEPS FOOD GREEN
The look of lush, green leafy vegetables automatically makes one think of freshness while a tinge of yellow on the same leaves reminds you of food that is past its shelf date. That is the kind of influence the colour green has on our minds, especially when it comes to plants. That green colour is due to the presence of chlorophyll in the leaves. As we know, plants make their own food and produce energy and convert carbon dioxide into oxygen during the time. This process is known as photosynthesis. In addition to sunlight, carbon dioxide and water, plants require an important ingredient for photosynthesis. And that is chlorophyll which gives plants a natural colour of green.
WHAT IS CHLOROPHYLL?
Chlorophyll is a group of molecules that regulate the capture of sunlight in a regulated fashion so that the plants can process it and produce their food and energy. In addition to contributing to the process of photosynthesis, chlorophyll also gives plants the colour green because that is the part of the colour of sunlight that it filters into the plants. This green colour can be seen on the leaves, the stalk, the sepal of flowers, and on the grass growing on the ground. Depending on the amount of chlorophyll present in the plant, the shade of green seen on it will vary.
DO FOOD PLANTS LOSE CHLOROPHYLL ON PROCESSING?
Chlorophyll does not have a unique molecular configuration. Since it is not very stable, the molecules can break or change configuration quickly even if there is a slight change or impact. In the case of food, the chlorophyll food colouring is impacted by acidity, heat or damage. This is why green leafy vegetables can quickly enhance their green food colouring on being blanched or immersed in hot water while leaves like spinach can turn yellow when kept in the fridge.
Instead of blanching, if the green food is left in hot water for a longer period, it will lose its green colour. This is because the food is impacted as much by the acidic nature of water as by the heat of boiling water. The colour then leaches out when the chlorophyll molecules break apart and the vegetable turns much paler in colour.
Also, chlorophyll is of two types – Chlorophyll A and Chlorophyll B – which differ in stability and heat sensitivity. Most plants contain both types of chlorophyll but in different proportions. Plants that contain more of chlorophyll a are likely to be more stable in colour than those which contain more of chlorophyll b.
CAN GREEN FOODS RETAIN THEIR COLOURING?
Foods that are naturally green due to the presence of chlorophyll can be kept green by following a few simple steps:
- Foods will retain their green colour if the cooking time is kept short and too much heat is not applied on them for long periods of time.
- Acids act against the chlorophyll. Using alkaline ingredients like baking soda can counteract the impact of acidity and keep the food green. If you do need to add acidic substances (like salad dressings), add them only at the last minute before serving.
- Keeping the green foods in areas that have a higher concentration of carbon dioxide and lower presence of oxygen can be beneficial for retaining the green colour.
- The best way to retain the colour of fresh, green vegetables is, of course, to eat it quickly. This is also a healthier way to eat vegetables.
