A tomato sauce is any of a very large number of sauces made primarily out of tomatoes, usually to be served as part of a dish (rather than as a condiment). Tomato sauces are common for meat and vegetables, but they are perhaps best known as sauces for pasta dishes. Tomatoes have a rich flavour, low liquid content, very soft flesh which breaks down easily, and the right composition to thicken up into a sauce when they are cooked (without the need of thickeners like roux).
Ketchup, (also spelled catsup) is a condiment, usually made from tomatoes. The ingredients in a typical modern ketchup are tomato concentrate, spirit vinegar, corn syrup or other sugar, salt, spice and herb extracts (including celery), spice and garlic powder. Allspice, cloves, cinnamon, onion, and other vegetables may be included. Ketchup started out as a general term for sauce, typically made of mushrooms or fish brine with herbs and spices.
Tomato paste is a thick paste made from ripened tomatoes with skin and seeds removed. Originally it was an artisan product that is still made the traditional way in parts of Sicily, Southern Italy and Malta. The artisan product is made by spreading out a much reduced tomato sauce on wooden boards. The boards are set outdoors under the hot August sun to dry the paste until it is thick enough, when scraped up, to hold together in a richly coloured dark ball.
The definitions of tomato purée vary between regions. In the USA, tomato purée is a processed food product, usually consisting of only tomatoes, but can also be found in pre-seasoned form. It differs from tomato sauce or tomato paste in consistency and content; tomato puree generally lacks the additives common to a complete tomato sauce, and does not have the thickness of paste. To prepare tomato purée, ripe tomatoes are washed and the leaves and stem are removed.
The ketchup as a vegetable controversy or ketchupgate refers to a proposed United States Department of Agriculture (USDA) Food and Drug Administration directive, early in the administration of Ronald Reagan, that would have reclassified ketchup and pickle relish from condiments to a vegetable, allowing public schools to cut out a serving of cooked or fresh vegetable from hot lunch program child-nutrition requirements.
Tomato pomace is an inexpensive by-product of tomato manufacturing. Effectively, it is what is left-over after processing tomatoes for juice, ketchup, soup, etc. It is sometimes used in pet and livestock food manufacturing as a source of dietary fiber, as well as B vitamins, Lycopene and (to a lesser extent) vitamin A. As the primary component of tomato pomace is the tomato skin, it has the potential for higher amounts of pesticide residues than tomatoes themselves.
New research suggests that the form of tomato product named FruHis could be the key to unlocking its prostate cancer-fighting potential, according to a report in the journal of the American Association for Cancer Research. Dried fruits and vegetables are known for their high content of D-fructose-amino acids, or Amadori compounds. D-fructose-L-histidine or FruHis is a ketosamine present in dried fruits.