It’s tomato time for gardeners and cooks. Our efforts to grow this botanical fruit used as a vegetable from seed since January or February have been helped this year by the hot summer, producing earlier and more abundant crops. For the last month we have had the pleasure of eating them and pondering once again why their taste and flavour are so remarkably better than the commercial varieties available in most shops and supermarkets.
It turns out that tomatoes are one of the principal food sources, representing about 25 per cent of the European Union’s fresh vegetable output. Major producer countries are China, the US, India and Turkey and in Europe Spain, Italy, Poland and the Netherlands. World production is put at 170 million tonnes, with exports valued at $88 billion.
Up to 10,000 different varieties of tomato are chronicled. Solanum lycopersicum, to give its Latin name, is a member of the nightshade family along with potatoes, bell peppers, aubergines, petunias and tobacco. The earliest evidence found of the plant is from Antarctic fossils 50 million years ago. Its long-standing culinary use by Aztecs in south and central America was brought to sixteenth Europe along with its name by the Spanish conquistadores. Tomatoes spread gradually among poorer people from the Mediterranean to northern Europe in the following two centuries and went worldwide from the 19th century.
Tomatoes spread among poorer people from the Mediterranean to northern Europe and went worldwide from the 19th century
Tomatoes are one of the most studied fruits, and raise many issues about regulation and ethical practice, according to the Spanish biogeneticist Antonio Granell from the University of Valencia. He and his team have studied the tomato genome and, working with 300 other scientists and taste panels from around the world, have identified the genetic differences between commercial and localised heirloom varieties of the fruit. The tomato is easy to transform genetically by improvement, selection and crossing, which is what growers and seed producers have been doing ever since the tomato became a widely used food.
Granell says much of the producer and seed company effort is directed towards reducing disease in commercial varieties. That ensures they can be transported long distances to markets and can then have a longer shelf life. Other commercial research goes into producing tomatoes that are red, round, firm and reasonably priced. Tomatoes with tougher skins like the aptly named Moneymaker variety travel better without being damaged.
Such uniformity makes for a standardised commodity with more appeal to the eye than the taste. In fact research establishes conclusively that taste and flavour have been sacrificed for year-round availability of commercial tomatoes grown far away from their markets. Granell’s team identifies inactivity of the GLK2 gene as specifically responsible for loss of sugars. It was suppressed because it produces green traces and cracked skins.
Research establishes conclusively that taste and flavour have been sacrificed for year-round availability of commercial tomatoes grown far away from their markets
Other researchers have distinguished between the sweet sugars produced by tomatoes (one of the five tastes encountered by the mouth along with sourness, bitterness, saltiness and umani) and the volatile gases responsible for flavours encountered in the nose (lost if you refrigerate tomatoes). Both are indispensable features of the heirloom tomatoes gardeners grow and appreciate, but have been reduced or lost in commercial varieties.
These researchers say it is possible to identify and restore volatiles to commercial varieties, even though sugars would remain reduced because they take more time to develop than is allowed commercially, in order to maximise yields and shorten expensive picking costs. Granell says “once a series of protocols to ensure there is no risk has been established, genetic modifications are just another way to obtain a product that people like and is beneficial”.
The industry relies on huge numbers of migratory workers to pick the tomatoes. In southern Italy, many of them have been on strike recently against exploitation and low wages. “We are not slaves” is their slogan.
A world record of 252 varieties of heirlooms put on show was established at the Totally Terrific Tomato festival in Dublin’s Botanic Gardens last month. The organisers say it is essential to preserve and celebrate them as a source of generic diversity, taste and flavour. Favourite varieties they recommend are Rosana for all-round use, Blush for its many fruits and Pontane as a large beefsteak one.
I will add these to my favourites grown outdoors this year: Northern Lights as a marvellously intense beefsteak; Latah as an excellent early ripener; and Tangitel as a subtle tangerine cherry. Best eaten in a salad with a little salt, the best olive oil, chives, tarragon or basil, along with some cheese.