Tomatoes

Tomatoes
© Denzil Green

Tomatoes were brought over to Europe by the Spanish in the 1500s, and took off right away.

The varieties brought over were small, tart, and often shades of yellow. There was some suspicion that they might be poisonous. Still, Italians took to them right away, but outside Italy people continued to regard them with suspicion until the 1800s.

Aside from the glorious few summer months when local field tomatoes flood the stores and the markets, we have gotten used to tasteless tomatoes in our shops. Tomatoes are harvested green, hard and unripe because they ship better that way, suffering less damage from handling and jostling during transport. When they arrive, they are “ripened” artificially using ethylene gas, which unfortunately only ripens the colour, not the flavour. The gas doesn’t cause the banal flavour; that is the result of the tomatoes being plucked prematurely away from the nutrients that they would have gotten on the plant’s stem, and no amount of gas or time in a window sill can make up for that.

If you are cooking with tomatoes out of season, in fact, you are far better off to use canned tomatoes. They will have been harvested and canned when naturally ripe, and so have better flavour — plus they will be cheaper and easier to use in cooked sauces, with a lot of the work having been done for you.

When buying tomatoes in season, resist the instinct to judge them on how pretty they look. Smell the stem end of the tomato, and check for the scent of the plant itself. A good plant scent is a pretty good indication of a very flavourful tomato. Sometimes the less-pretty ones will be the far wiser choice.

There are two types of tomato plants: determinate, and indeterminate:

• Determinate ones set flowers at the top, causing the plant to stop growing in height.
• Indeterminate ones produce flowers elsewhere instead, and keeping growing in height.

Determinate ones tend to set their fruit all at once, and ripen earlier. Indeterminate ones tend to be older, heritage varieties, and are often considered to produce more flavourful tomatoes. The fruit will ripen at various times, though, and possible very late into the season.

Tomato plants tend to grow true to seed.

Europeans have always treated tomatoes as a vegetable, even though technically they are a fruit.

Peeling Tomatoes

Tomato skins do tend to toughen during cooking, which is why many recipes have you peel them. Peeling them, unfortunately, can be quite fiddly.

Fill a sink or large bowl with very cold water, and bring to the boil a large pot of water. Meanwhile, cut an each on the bottom of each Tomato. Drop a few tomatoes at a time into the boiling water, leave them there for a minute or two, then remove from the water with tongs or a slotted spoon and place them in the cold water (some varieties may need 3 to 5 minutes.) When cool, use a paring knife to help coax the skins off.

If you have any amount of tomato skins to speak of, you can make a tomato peel powder which you can use to jazz up salads, pastas or devilled eggs. Lightly oil a sheet of waxed (or parchment paper), place it on a baking sheet, distribute the tomato skins on it and bake for about 45 minutes at 110 C ( 225 F). Pulverize the dried skins in a blender, coffee or spice mill, etc, till they are a fine powder, and store refrigerated in a sealed container for up to a month, or freeze for up to 6 months.

Cooking Tips

To seed tomatoes, cut in half cross-wise. Squeeze each half over a bowl, saving the seeds and pulp for sauces. Suggestion: only do this for baked, stuffed Tomato recipes.

A pinch of sugar, stevia, etc enhances the sweetness of tomatoes, whether you are cooking them or serving them fresh sliced or chopped.

Baked stuffed tomatoes sometimes collapse outward while cooking; cooking them in greased muffins tins will give them support.

Substitutes

There isn’t really a substitute for tomatoes, but with their being so readily available, and affordable, there is no real need for a substitute.

Nutrition

The highest concentration of Vitamin C in Tomatoes is found is the jellylike material at the middle surrounding the seeds.

Overall, an excellent source of vitamin C, and a good source of vitamin A.

Tomatoes contain antioxidants called flavenols (which are what make tomatoes red). There are two bits of good news about this: the first is that such antioxidants may help to reduce aging effects and risks of heart disease and cancer; the second is that these antioxidants in tomatoes aren’t affected by cooking or processing.

It’s a health myth that acidic fruits and vegetables, such as tomatoes, can worsen the condition of an arthritis sufferer. The acidity level is nothing compared to the acidity already in our body — in our stomachs.

Tomato leaves

Because tomatoes belong to the Nightshade family, or to put more fine a point on it, the deadly Nightshade family, some Europeans felt that tomatoes were poisonous. It took several centuries for tomatoes to become the pervasive staple that they are.

Tomato leaves have long been suspected of being poisonous. Tomato leaves contain “tomatine”, equivalent to the “solanine” in green potatoes. Tomatine is also present in green tomatoes, though it is concentrated in the leaves and flowers. Some people report that skin contact with tomato leaves can cause rashes, hives and other forms of contact dermatitis. The “Poisonous Plants of North Carolina” database lists leaves and stems as toxic. [1] In Latin America, where tomatoes originated, there don’t appear to be any instances of the leaves being used as food for humans or animals.

Harold McGee, the food researcher, takes issue though with the notion that tomato leaves are toxic when ingested. [2] He cites George E. Burrows and Ronald J. Tyrl writing in “Toxic Plants of North America” (Iowa State University Press, 2001) that a toxic dose of tomatine for humans would requiring eating a pound (450g) of tomato leaves. He also cites research done in the year 2000 by a Dr Mendel Friedman of the American Department of Agriculture, who had some preliminary findings that might indicate that almost all tomatine passes through the body, binding with undesirable LDL cholesterol and taking it out with it. [3]

Paul Bertolli, the California chef and author, calls for tomato leaves in a sauce in his 2003 cookbook, “Cooking by Hand.”

Nevertheless, many people are holding out on eating tomato leaves until more conclusive studies are available.

Equivalents

1 pound (450g) tomatoes = 3 medium round = 8 plum = 2 cups chopped

1 medium round tomato (about 3 plum tomatoes) = 150 g (5 oz) = ¾ cup to 1 cup, chopped
2 ½ pounds (1.1 kg) tomatoes = 3 cups chopped and drained fresh tomatoes = 2 ½ cups chopped and cooked tomatoes = 2 ½ cups canned tomatoes in puree or juice
25 to 30 cherry tomatoes = 1 pint/punnet = 2 cups chopped tomatoes
1 medium tomato = ¾ – 1 cup of chopped tomato
1 bushel of tomatoes = 50 to 55 pounds = 22 ½ to 25 kg = approx 70 cups / 550 oz / 17ish litres of simmered-down sauce
1 kg chopped = 1 litre in volume
2 ¼ pounds, chopped = 1 US quart in volume
11 kg (25 lbs) roma-style tomatoes yield approximately 600 to 700 g (4 cups / 21 to 25 oz) of fresh, undried tomato peel
½ cup (125 ml / 4 oz) tomato purée = 1 tablespoon powdered tomato (Source: So Easy to Preserve, 2014, page 364.)
1 medium tomato = 1 tablespoon powdered tomato (Source: So Easy to Preserve, 2014, page 364.)
20 pounds (9 kg) tomatoes = 18 oz (500 g) dried sliced tomato (Source: So Easy to Preserve, 2014, page 364.)
3 medium round or globe tomatoes = 500 g / 1 lb = 2 ½ to 3 cups chopped = 350 ml (1 ½ cups) crushed tomatoes (Source: Ball / Bernardin Complete. 2015. Page 247)
5 medium plum or Roma tomatoes = 500 g / 1 lb = 2 cups chopped = 350 ml (1 ½ cups) crushed tomatoes (Source: Ball / Bernardin Complete. 2015. Page 247)

Storage Hints

Store cut tomatoes in the fridge. Wrap them in cling film or put in a sealed plastic container.

Don’t refrigerate fresh, uncut tomatoes. Cold temperatures damage the membranes inside the walls of a tomato, making the tomato flesh mealy, and affecting the flavour. Store at room temperature. When cut into, then store in refrigerator. The exception is when they are extremely ripe: then, you should store in fridge to delay spoilage for a few more days (or wash, core and freeze for future cooking uses.)

If you have unripe tomatoes, place them in a dark spot for a few days. This works far better than placing them in the sun, as placing them in the sun can often soften them.

Some suggest placing them in a paper bag as well.

The Ball / Bernardin Complete Book of Home Canning agrees with “out of sun” aspect, but seems to want more ventilation:

“To ripen tomatoes for canning, empty them from the basket or box onto a single layer of newspaper or a large mesh rack. Store in a cool (but not cold), dry place, out of direct sun. Turn tomatoes daily to prevent spoilage and soft spots. As the tomatoes ripen, sort into different stages of ripeness and use the ripest ones first.” ^[1]Kingry, Judi and Lauren Devine. Ball / Bernardin Complete Book of Home Preserving. Toronto: Robert Rose. 2015. Page 371.

But before you serve a fresh tomato, consider placing it in a sunny spot for a few hours. It helps to wake up the taste.

Freezing Tomatoes

To peel: Boil for about 60 seconds, plunge into cold water.

Gradual heating process: Chop a few prepared tomatoes, put in pot over high heat, mash them a bit, heat until juice is released. Chop and add a few more, waiting for pot to return to a boil afterwards. Repeat process until all are in pot. The gradual chopping and heating inactivates an enzyme that otherwise causes separation of tomato liquids and solids.

As stewed tomatoes: Wash. Peel. Core. Use gradual process above, and when all are in pot, simmer for 15 more minutes. Let stand to cool. Pack and freeze, leaving space for expansion.

As juice: Wash. Use gradual process above, and when all are in pot, simmer for 5 to 10 more minutes. Pass through sieve or mill. (Or, peel and core first, then cook using gradual process, then put through blender, then strain to remove seeds and any remaining solids.) Let cool. Pack and freeze, leaving space for expansion.

Raw: Wash. Peel. Core. Cut into chunks. Pack, squeezing them to release juice to help cover them. Freeze, leaving space for expansion. Use for cooking.

Whole: Wash, put on a baking sheet, place in freezer overnight. In the morning, bag them and return to freezer. To use, thaw, and use as directed in your recipes that involve cooking tomatoes. When thawed, the skin will pop off easily. You may experience separation of tomato liquids and solids as the tomatoes thaw.

Puréed: Wash. Peel. Core. Purée in a blender, strain excess liquid off, pack in freezer bags and freeze.

On the whole, though, some feel stewed tomatoes are the best way to freeze tomatoes. That way, with the tomatoes being stewed, they are ready to go as the base for quick sauces. And, if you used the gradual heating process, you won’t experience the separation of tomato liquids and solids after thawing that requires long simmering time to drive off the excess liquid.

History Notes

The Franciscan priest Bernardino de Sahagún (1499 – 1590), in his book “Historia General De Las Cosas De La Nueva España”, records seeing tomatoes of all shapes, sizes and colours for sale in 1519 at the Tlateloco market in Tenochtitlan, Mexico.

The Spanish brought some tomatoes back to Europe as early as 1523 for use as a garden ornamental. These were nothing like ours today, though. They were very hairy plants that had a green powder all over them that brushed off on you, and the fruit itself was lumpy and yellowy. They weren’t exactly photogenic. And, gardeners recognized them as belonging to the deadly nightshade family of plants.

In 1544, Italian botanist Pietro Andrea Mattioli (1501-1577) recorded tomatoes in the Mediterranean in his book, “Di Pedacio Dioscoride Anazarbeo”, describing them as yellow and referring to them with the Latin phrase of “mala aurea” (“golden apple”, or in Italian — “pomo doro”, which is still the name in Italian today for apples.) He mentions his belief that they were unwholesome to eat, though he did say he saw them being eaten, fried in olive oil and seasoned with salt and pepper. He records red as well as yellow tomatoes. [4]

Acceptance was slow. Bartolomeo Scappi, who cooked for six Popes and so had access to any ingredient he wished, did not even mention tomatoes in his 1570 cookbook, “Opera di Bartolomeo Scappi.”

Slowly, over the decades and centuries, Italian gardeners bred away the lumps on tomatoes, the thick skins, increased their plumpness, and bred in the gorgeous red colours.

At first, the Italians largely used tomatoes in salads. One of the first recipes to use tomatoes for a sauce was “Salsa di pomodoro, alla spagnuola” in the book “Lo scalco alla moderna” by Antonio Latini in 1692. But frequent mentions of tomato sauces on pasta didn’t start happening until the 1800s.

Elsewhere in Europe and in North America, tomatoes were grown as a non-edible garden curiosity up until the end of the 1700s. By 1812, they were being used as food in New Orleans; by the mid-1830s, people in the North Eastern States were also growing them as food (though some cooking instructions specified cooking tomatoes for at least three hours to ensure they lost their “raw” taste.) In England, the adoption of tomatoes as a food item roughly kept the same pace as in America, but also mostly just for sauces and some soups. By the 1900s, the tomato had pretty much gained international acceptance for eating both cooked and raw.

Prior to the 1940s most commercially-grown tomatoes would start to ripen with dark shades of green around the top stem end, and lighter shades at the bottom. Then, tomato plant breeders happened upon a variety of tomato with a gene mutation that would ripen uniformly all at once, going from a uniform light green to a uniform red. The breeders were interested in this not just for the look of a tomato, but also for ease of harvesting in huge, industrial-size fields. It let growers look at a field of tomatoes and know that the entire field would be ready for harvest in a few days. But in selecting this variety and breeding out from it, they had accidentally selected a tomato with a disabled protein vital for regulating the SlGLK2 gene in tomatoes. This gene previously optimized photosynthesis in the tomato.

“To test their discovery, the researchers used genetic engineering to turn on the disabled genes while leaving the uniform ripening trait alone. The fruit was evenly dark green and then red and had 20 percent more sugar and 20 to 30 percent more carotenoids when ripe. But were the genetically engineered tomatoes more flavorful? Because Department of Agriculture regulations forbid the consumption of experimental produce, no one tasted them.” [5]

Upping the amount of GLK protein in tomatoes might also be useful in the tomato processing industry, which requires processed tomato products to have high sugar content. “If you start off with tomatoes that have more sugars to begin with, then these companies have to do less cooking, less handling. It’s cheaper… [6]

Consumers would currently likely rejected genetically modified tomatoes, but the lead researcher, Dr Ann Powell, says there’s another answer — “Heirloom tomatoes and many wild species do not have the uniform ripening mutation. The idea is to get the vegetable seed industry interested.” [5]

Literature & Lore

The word tomato comes from an Aztec or Nahuatl word, “tomatl.”

“Knowledge is knowing that a tomato is a fruit. Wisdom is knowing that a tomato doesn’t belong in a fruit salad.” — Miles Kington (1941 – 2008, British columnist.)

Language Notes

Tomatoes (with an “e) as a plural is relatively recent. In her 1824 book called “The Virginia Housewife”, Mary Randolph spelt it “Tomatos.”

In Germany, consumers have nick-named the standard supermarket-type of flavourless, artificially-ripened tomatoes “Wasserbomben” (water bombs.)

Sources

[1] “Poisonous Plants of North Carolina.” Maintained by Dr. Alice B. Russell, Department of Horticultural Science, North Carolina State University. Retrieved July 2011 from http://www.ces.ncsu.edu/depts/hort/consumer/poison/Lycopes.htm

[2] McGee, Harold. Accused, Yes, but Probably Not a Killer. New York Times. 28 July 2009.

[3] Food and Chemical Toxicology, July 2000 v.38, no.7 pp. 549-553. Note that Friedman’s research, which has continued up until at least 2009, appears for the most part to have been done with green tomatoes, not leaves.

[4] “Quei pomi, che si chiamono in Lombardia Melanzane, e in Toscana Petranciani … Portasene à i tempi nostri un’altra spetie in Italia, le quali si chiamano POMI d’oro. Sono queste schiacciate come mele rose, e fatte a spichi, di color prima verdi, e come sono mature in alcune piante rosse come sangue, e in altre di color d’oro. Si mangiano pur anch’esse nel medesimo modo…. Mangiansi volgarmente fritte nell’olio con sale, e pepe, come i fonghi”. (1557 Italian translation.)

[5] Kolata, Gina. Flavor Is Price Of Scarlet Hue Of Tomatoes, Study Finds. New York Times. 29 June 2012. Page A12.

[6] Stastna, Kazi. Supermarket tomato’s even colour comes at expense of taste. CBC. 2 July 2012. Retrieved July 2012 from http://www.cbc.ca/news/technology/story/2012/06/28/sci-tomato-taste.html

Bailey, Pat. Discovery may unlock heirloom taste in new tomatoes. The Davis Enterprise. 28 June 2012. Retrieved July 2012 from http://www.davisenterprise.com/local-news/ag-environment/discovery-may-unlock-heirloom-taste-in-new-tomatoes/

Damrosch, Barbara. Taming the unruly tomato vine. Washington Post. 25 May 2011.

Friedman, Mendel, et al. Tomatine-Containing Green Tomato Extracts Inhibit Growth of Human Breast, Colon, Liver, and Stomach Cancer Cells. Journal of agricultural and food chemistry. 2009 July 8, v. 57, no. 13. p. 5727-5733. Retrieved July 2011 from http://ddr.nal.usda.gov/dspace/bitstream/10113/35176/1/IND44232438.pdf

Powell, Ann, et al. Uniform ripening Encodes a Golden 2-like Transcription Factor Regulating Tomato Fruit Chloroplast Development. Science 29 June 2012:
Vol. 336 no. 6089 pp. 1711-1715.

Tomato. Watch your garden grow. University of Illinois Extension. Retrieved July 2011 from http://urbanext.illinois.edu/veggies/tomato.cfm

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