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    Tomatoes: GM, Aroma And Tradition
    By Enrico Uva | April 25th 2012 08:30 AM | 15 comments | Print | E-mail | Track Comments
    About Enrico

    I majored in chemistry, worked briefly in the food industry and at Fisheries and Oceans. I then obtained a degree in education. Since then I have...

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    For our frugal parents in the late 1960's, pressure cookers and mason jars were not an option. In fact, since our tomato-dominated gardens couldn't provide the needed volume, our extended family drove to farms to pick more tomatoes, often overfilling allotted baskets.

    Then back home, not for ecological reasons but strictly to lower costs, any glass container in sight was recycled, filled with crushed tomatoes and topped with a basil leaf. Jars and bottles were placed in big oil drums, and fires were lit in the fields behind our suburban homes so we could preserve sauce for the long, upcoming winter.


    When we carry out traditions, we are under the illusion that we are repeating acts dating back to the dawn of our culture. But a few years later, as an adolescent, a plaque at Montreal's Botanical Gardens made me aware that tomatoes are not indigenous to the Old World, let alone Italy. Pasta can be traced to the Roman Empire or at least to Marco Polo, but it was eaten without tomato sauce.

    Even after tomatoes were brought in from South America or Mexico (there are two competing hypotheses with not enough evidence to declare a winner) they were assumed to be poisonous because of their similarities to mandrake and belladonna. Finally, at some point between the 1600's and 1700's, tomatoes were used for culinary purposes in southern Europe, but the custom did not become widespread until the 1860's when they were first mass-produced.

    When it comes to classifying the tomato, many have experienced confusion, regardless of their knowledge of botany. Aside from the Nix versus Hedden issue, people forget or ignore that the seeded berry grows from a flower; they persist in calling it a vegetable because it is not as sweet as a pear or a cantaloupe, and it's not tossed into a fruit salad. The same applies to other fruits such as peppers, cucumbers and squash. But for a long time, botanists incorrectly classified the domestic tomato as Lycopersicon esculentum, even though Linnaeus in 1753 along with prior taxonomists realized merely from morphological features that it belonged to the same genus as that of wild tomatoes and potatoes. The current classification of Solanum lycoserpicum is based on comparative chloroplast DNA analyses and other molecular studies.

    Constant artificial selection, the first form of genetic modification of tomatoes, probably took place in Mexico and Western South America, where the tomato was first domesticated, and it continued later and more intensely in Europe. One of the many resulting changes involved flower structure. The female part, the stigma, has become less protruding and, in the case of commercial varieties, completely surrounded by the fused anthers. This has increased fruit yield, but by preventing cross-pollination, it has reduced genetic variation.

    For a while, only the odd spontaneous mutation would cause change. Then in the 1990's transgenic tomatoes appeared and some failed even before the irrational EU ban of GM foods came into effect. The single-gene approach had been oversimplistic. The Flavr Savr tomato was given a gene that interfered with the production of an enzyme that would normally soften the fruit. The shelf life was indeed extended, but the firmness was not really improved, and the GM fruit could not be harvested when ripe.

    Tomato researchers realized that the genetics of a quantitative trait is hard to investigate. The effect of one gene is small and often influenced by environment or by the interaction with other genes. Many tomato traits are genetically controlled by a combined action of quantitative trait loci(QTLs) with favorable allelic genes found in wild species grown in Ecuador, Peru, Chile and even in the Galapagos.

    Having spent many hours of my youth picking tomatoes, I've always been fascinated by the aroma of tomatoes and by the smell exuded by stems alone. Here are some examples of volatiles found in fresh tomatoes, which some have been investigating not for my nostalgic reasons but with the hope of accentuating aroma through genetic modification.

    COMPOUND
    CONCENTRATION in tomato
    in
    ppb(parts per billion= mg per 1000 L)`

    Human threshold in ppb
    Other notes
     Structure
     cis-3-hexenal  12000  0.25 fresh green aroma; increases  in conc.after tissue disruption  
     b-ionone   4  0.007    
     hexanal  3100  4.5 suppressed by alcohol in tomato; increases after tissue disruption  
     b-damascenone  1  0.002    
     1-penten-3-one  520  1.0 increases after tissue disruption  
     cis-3-hexenol 
     150  70.0    
     6-methyl-5-hepten-2-one  130  50.0 fruity aroma  

    Annually 100 million metric tons of tomatoes are produced worldwide. The leading consumers are Mediterranean countries with 60-100 kg eaten per capita per year. The combination of poverty and lower popularity of the tomato elsewhere in the world creates an overall global annual consumption of only 14 kg/cap/y. The leading producers are China, US, India, Turkey, Egypt, Italy and Spain. Ironically, Italy has become China's largest customer for the type of tomato used to make tomato paste.

    Paste, which has a lower water content than fresh tomatoes, is understandably more concentrated in vitamins A, C and the reddish compound lycopene.
    In test tube studies, lycopene is the best antioxidant among carotenoids. But the same was said of anthocyanins, and then evidence for the in vivo effect turned out to be scant. With lycopene, however, some supportive epidemiological studies have also been done. While the Mayo Clinic maintains that the cancer-preventive action of lycopene is still controversial, many researchers nevertheless believe that increasing the content of lycopenes and other phytochemicals is a worthwhile pursuit, but that it won't be successful without an interdisciplinary approach.

    ** in tomato photo: my daughter, about 14 years ago.

    SOURCES:

    Genetic Improvement of Solanaceous Crops
    Autar K. Mattoo. Maharaj K. Razdan


    First Fruit: The Creation of the Flavr Savr Tomato and the Birth of Biotech Foods
    Belinda Martineau

    The Chemistry of Fresh Tomato Flavor
    Emin YILMAZ
    TURKEY Turk J Agric For25 (2001) 149-155


    Volume 29, Number 3 (2010), 553-568, DOI: 10.1007/s10555-010-9246-z
     


    Comments

    Hank
    they were assumed to be poisonous because of their similarities to mandrake and belladonna.
    And if people eat them the way they eat a lot of fruits, they are poisonous - though it takes quite a few to get enough arsenic to be deadly.
    UvaE
    And if people eat them the way they eat a lot of fruits, they are poisonous - though it takes quite a few to get enough arsenic to be deadly
    Relative to tomatoes, there's at least twice the amount of arsenic (Bangladesh J Pharmacol 2007; 2: 88-94) in  papaya and beans and over 50% more in pumpkins. With an average of 0.71 X10-6 g of arsenic per gram of tomato and a lethal dose of 1 mg/kg/day, a 75 kg adult would have to eat 105 kg of tomatoes in 1 day to die from arsenic poisoning!
    Hank
    Well, smart assassins just crush up the leaves and distill it.
    UvaE
    Yes, but they would have to hoard even more tomatoes than we did as children :)
    UvaE
    I just remembered a study done by Stillwell in Connecticut at the time when arsenic was still used in treated wood. If tomatoes or other vegetables were grown in the vicinity of decks made with such wood, they would end up with abnormally high concentrations of the poison. But the greatest concentration would occur in roots, then stems and the lowest in fruits, so the consumption of things like carrots and potatoes was riskier than that of tomatoes.

    Another fascinating thing was that when treated wood was first approved, it seemed safe because very little arsenic was leeched out during lab tests. But in the field, more dissolved because treated wood was subjected to the lower pH's of acid rain.

    To test that explanation, I got hold of arsenic test strips and subjected chromated copper arsenate (CCA)treated wood to varying pH's and a higher concentration of arsenic was indeed released when the water was more acidic. 
    rholley
    When I was young, lead arsenate was still used on lawns to kill earthworms, since worm-casts were considered unsightly and messy.
     
    This may have been a particularly British use, because it is not mentioned in the Wikipedia article on this compound, although many different insecticidal applications are.
     
     
    Robert H. Olley / Quondam Physics Department / University of Reading / England
    How come the tomatoes in the supermarket look great and taste like cardboard? The ones in Mexico don't look as great but taste GREAT!

    UvaE
    Different priorities. Too many consumers don't buy tomatoes if they don't look great, placing pressure on growers to develop varieties that are tough towards transportation but which are not too aromatic or tasty.

    It reminds me of Big Island(Hawaii) oranges when I lived in Hawaii. They look like mutants but are delicious.
    rholley
    I have not had much success in growing tomatoes.  One year I only harvested five fruits before the plants succumbed to blight.
     
    This is a Black Russian (heritage) tomato from 2010.



    It is not the only food that we Old Worlders get from the Americas.  Here is the text of a small online article I wrote, for a Far Eastern readership, roughly 15 years ago.  Most of the information in it will be old hat to our regulars, but might it inspire a few more Enrico articles?
     
    Food from the Americas

    After Columbus reached the Americas in 1492, this not only changed the map of the world politically, but also changed the kitchens of Europe and Asia. Several new foods were brought back to Europe, of which I will discuss the major ones below.

    The TURKEY. This North American bird is, of course, primarily associated with the Thanksgiving festival in the USA. It has become standard in Britain for Christmas dinner, but only in this century, because being more amenable to factory farming, it is easier and cheaper to raise than the traditional goose. The name "turkey" arises because people here originally thought it came from the country of that name.

    MAIZE. This cereal was domesticated by the Pre-Columbian Indians. (They get this name because Columbus was actually trying to find a passage westward round the world to trade with India, and thought he had discovered it). Besides the basic cereal, it has been developed into several distinct varieties such as sweet corn and popcorn.

    The following four plants belong to the one plant family, called the Solanaceae after the botanical name for the potato.

    The POTATO. This plant was widely cultivated in Peru, but was introduced to Europe from North America. For many years, people treated it as a garden curiosity, and did not know that the underground tubers were edible. The King of France wanted his people to grow it, but the suspicious peasants would not accept it. So he grew some in a walled garden guarded by soldiers, and the peasants came by night to steal this special royal vegetable, and so it gained acceptance. Because of its ease of cultivation and productivity, it tended to displace cereal crops in many parts of Europe. In 1845 and 1846, a fungus disease called blight struck the potato crop and caused famine in several countries in Europe. Because of social conditions, this was particularly disastrous in Ireland (which was then ruled by Britain). The British government tried to send some aid, but just like aid to famine-stricken countries in the third world today, it was hampered by inefficiency, and opposed by vested interests in Britain and in Ireland itself. Many Irish people died, many more emigrated to America. The descendants of some of these people are still very bitter against Britain.

    Many members of the potato family are poisonous. Even potatoes themselves should not be left in the light, or they will turn green and accumulate a poisonous substance called solanine. The fruits of the potato (red berries like small tomatoes) are poisonous also.

    The TOMATO. This plant is closely related to the Potato, in fact you can graft a tomato stem onto a potato root to produce both vegetables from one composite plant, but this is not a very efficient way of growing either. When this plant was first introduced, people thought their fruits were poisonous, because of their similar appearance to potato fruits. They were given the name "love apples". After they were found to be harmless and edible, they very rapidly became popular, especially in Italy where they form a basic item in the national cuisine. (The art of making spaghetti is thought to have been brought back from China by Marco Polo, so that famous dish containing both items, Spaghetti Bolognese, was quite unknown to the ancient Romans).

    The CAPSICUM. This plant occurs in two major species, the chilli (
    辣椒) and the SWEET PEPPER (甜椒). A slightly hot version of the sweet pepper called paprika is very much used in Hungarian cooking. But it is the much hotter chilli which has really conquered the world, largely displacing the totally unrelated black pepper in India and Indonesia, besides dominating cooking in its home in Mexico, and in Sichuan. From the plant's point of view the hot principle is not, surprisingly, a chemical defence against insects, but a means of seed dispersal. The parrots which eat the fruits get a "kick" out of the capsicain, and come back for more, in the meantime depositing the seeds far away from the parent plant. We human beings also find that this substance gives us a feeling of well being, and in Britain some people have become mildly addicted to curry as a result.

    So in Ireland, Italy, Hungary and Sichuan, the characteristic "national" or "regional" food is really a recent introduction from the Americas. Cook turkey with potatoes, sweet corn, tomatoes and chilli, and you have an all-New-World dish!

    TOBACCO. This is not a vegetable, but it belongs to the same plant family. Its use was discovered by the Red Indians, and brought back to England by that famous explorer, Sir Walter Raleigh.
    Robert H. Olley / Quondam Physics Department / University of Reading / England
    UvaE
    It's just too damp in England, Robert. You have to move to Northern Italy! :)

    With regard to the origin of pasta, I may have been influenced by Italian museums because I too originally believed it was from China. But according to this article from the Atlantic, you are probably correct.

    Italians insist as a point of national pride that they invented pasta in their part of the world, despite considerable evidence that they did not. They cite as proof a set of reliefs on an Etruscan tomb dating from the fourth century BC, which depict a knife, a board with a raised edge that resembles a modern pasta board, a flour sack, and a pin that they say was made of iron and used for shaping tubular pasta. The Museum of the History of Spaghetti, owned by Agnesi, a pasta manufacturer near Turin, makes much of these reliefs, as do most histories of pasta—including the standard one, Anna del Conte's Portrait of Pasta. The reliefs do not persuade the American historian Charles Perry, who has written several articles on the origins of pasta. "There are plenty of things to do with a pin besides shape pasta," he says. In fact, Perry says, no sure Roman reference to a noodle of any kind, tubular or flat, has turned up, and that makes the Etruscan theory even more unlikely, given that the Romans dominated Italy soon after the Etruscans did.
    Thanks for this post -- I loved reading it! Just this morning I picked my first homegrown tomatoes of the season.
    I am trying a "black cherry" variety for the first time in addition to the old standby's I'm already harvesting... they are later bloomers so it will be a bit longer before I get to taste them.

    Re: blight, etc. I have learned through trial and error that the best way by far to deal with tomato pests of all types is to seek out a varietal which is resistant to those present in your area. Google for "tomato disease resistance codes" to learn more, here is one university site that has a table of them:
    http://vegetablemdonline.ppath.cornell.edu/Tables/TomatoTable.html

    You can even find particular "heirloom" varieties that will work well for you; you just may not be able to grow every one of them that strikes your fancy without a fierce battle. Why fight though when there are so many yummy ones to choose from? :)
    Also this way you don't have to worry about potential collateral harm to your pollinators as you might with any treatment you apply.

    UvaE
    Last year I had tomato plants that grew from seed on their own from my compost. They actually produced fruit! Normally, in our climate here in Montreal, plants have to started indoors. I kept the seeds and will toss them into the garden soon to see if the feat can be repeated.
    I enjoyed the article but i do have one minor bone of contention with it. You state (and probably in your mind rightfully so) that:
    ' Constant artificial selection, the first form of genetic modification of tomatoes, probably took place in Mexico and Western South America,.....'
    however I would take exception to the suggestion that natural selection and some minor crossing of varieties is 'Genetic Modification' in any way shape or form. My argument to this effect is that it is crossing varieties under the scrutiny of natural selection (which is something we have no control over whether financial or otherwise) and if it is permitted then we get another variety. If it is not then it fails to mature into anything other than either of its parents.
    GM on the other hand (also correctly referred to as transgenic modification as inferred in your article, genetically engineered and genetically modified, depending upon your particular source of educational material and field of research) is something altogether unnatural. We have interfered with natures natural process of selection by inserting genes from totally disparate sources into plants, and in more recent years animals, to introduce traits that are thought to be beneficial to the host in ways that will induce greater productivity or resistance to certain pathogens etc. Sadly the experimnent has not been an overwhelming success. We still know so little about the impacts of messing with evolutionary processes. We are fast approaching a time when we will either unleash something deadly onto the planet or create something that simply kills us. In fact it is anything but safe as far as a commercial proposition goes. The future of GM crops is now under serious pressure because of the inherent increases in use of chemicals needed to insure its success in the fields as well as increasingly obvious adverse side effects which hadn't even been considered before despite some of them being on the list of 'things to consider' before releasing GM organisms into the great outdoors. Human ailments from GM crops and the process of growing them are becoming increasingly common especially where heavy quantities of Glyphosate are used (RR soy) which have caused all sorts of health problems especially in South America. There is also growing evidence of cover ups of laboratory findings that would suggest that GM food is anything but safe to eat. However as with all things commercial the manufacturers will protest until the cows come home that its all okay (but only until they have as suitably profitable replacement to take its place) just as they did with DDT. It being the replacement for Arsenic and Lead based dressings in agricultural settings, particularly the fruit industry. There were others of even greater toxicity.
    Anyway I digress.
    For the record I grow all my own food that it is possible for me to grow as well as heirloom tomatoes. I utilise the permaculture techniques I learned from reading about and watching people like Bill Mollison and Sepp Holzer. I don't use chemicals and rely totally upon natural predators and complementary crop growing to keep the threats at bay. I find that this method of grwowing food is totally sustainable and very successful giving me plenty of food for myself and enough to share with friends and neighbours too.
    I live not much further North than Robert Olley. Just outside Banbury in North Oxfordshire to be precise. Weather at the moment is dire. Very wet and not very warm either. Hoping it will improve soon as it is the damp conditions that lead to blights and other fungal nasties.

    All- New Infographic & Analysis About Genetic Engineering Of Crops & GMO http://www.mapsofworld.com/poll/should-genetically-modified-foods-be-ban...

    All- New Infographic & Analysis About Genetic Engineering Of Crops & GMO http://www.mapsofworld.com/poll/should-genetically-modified-foods-be-ban...