Mr VegHead says...

Vegetable musings from Sea Spring Seeds
8
Nov

A Splash of colour in vegetables

Though I usually choose the fruit and vegetable varieties I grow for their yield and flavour, colour is gradually becoming a more important consideration. This shift in attitude is due in part to aesthetics as I start to appreciate the role that colour plays in the enjoyment of food. It is also partly due to the seed catalogues, which are offering an ever-increasing range of eccentrically-coloured vegetables and fruits. The carnival of colours is easily explained by the presence of pigments manufactured by the plants, and if it weren’t for these naturally-occurring chemicals, gardening would be dull and lifeless.

 

Chlorophylls

The soothing chlorophylls are present in almost all plants, imparting a green colour to leaves, stems and unripe fruit. These pigments are nature’s solar-powered batteries, capturing the energy from sunlight and helping to convert it into a form that the plants can use for growth and reproduction.

 

 

 

Nitrogen plays a key part of the make-up of chlorophyll, which explains why plants grown on soil low in this nutrient are not only stunted but don’t develop a lively green colour. The addition of a high nitrogen fertilizer will correct the problem, and the plants will quickly go green and start growing with renewed vigour.

Carotenoids

The extroverted carotenoids are a big and varied family responsible for most of the yellows and oranges as well as some of the reds found in fruit and vegetables. They give a warm yellow glow to sweet corn, a distinctive red to ripe tomatoes, and a sparkling yellow, orange and red to peppers.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Perhaps the best-known carotenoids are the carotenes found in carrots. Not only are they responsible for the characteristic yellow and orange colour of the roots, but they are the raw materials that our bodies use to manufacture Vitamin A.

To grow the healthiest carrots, you should delay the first harvests to give the roots time to develop. Your patience will pay dividends because carotene production lags behind root growth, and roots harvested too small will be pale and lacking in pigmentation. By waiting until the roots are bigger, you will give carotene a chance to accumulate and allow the crop to reach its full, health-giving potential.

Lycopene is another carotenoid that has life-enhancing qualities – it is an antioxidant that has received good press for the role it may play in reducing prostate cancer. The red colour of tomatoes is due to lycopene, which increases in quantity as the fruit ripen.

As with carotenes in carrots, gardeners can exercise some control over the manufacture of lycopene in their own-grown tomatoes. For example, temperatures above 30º C significantly reduce lycopene production, and venting tunnels and greenhouses during hot weather will help bring down the heat to reasonable levels.

Anthocyanins

The dynamic anthocyanins account for most of the reds, purples and blues in our fruits and vegetables. Without them, red currants and blue berries would be misnamed, and black currants – really a dark purple – wouldn’t exist.

 

Anthocyanins are water soluble, and in the kitchen, they don’t always live up to the promise they showed in the garden. This becomes clear when purple French beans and spouting broccoli are cooked in boiling water – the colour is washed out, transforming the vegetables to a rather ordinary green and changing the water to an uncharacteristic purple.

 

 

Cooking red cabbage can also be irksome, mostly because the colour is so fickle. Boiled in ordinary tap water, the cabbage turns out bluish or purple, a particularly unappetizing prospect for traditional chefs and diners. Fortunately, the situation is easily remedied by the use of something acidic such as vinegar – the colour then becomes the bright red commonly associated with pickled cabbage.

Betalains

Yet another group of pigments, namely the betalains, are responsible for the flamboyant colours of beetroot. They come in two versions, one producing the typical deep reds of most varieties, and the other responsible for the less common yellow of varieties such as Burpee’s Golden.

After they are ingested, red betalains are broken down and loose their colour. However, the extent of their breakdown varies from person to person, and to check where you stand, eat some red beetroot and wait for it to be digested. If the liquid you emanate at toilet time is red, then it is a sure sign that a high proportion of the pigment has passed through your body intact. This affliction, called beeturia, is harmless, though children might be frightened by the experience.

A Splash of Colour

Pigments are essential for our enjoyment of food. Some are necessary for plant growth, and their health-giving properties are responsible for our well-being. Their presence is often taken for granted, but without them, gardens and kitchens wouldn’t be the same.