On food and cooking the science and lore of the kitchen ( PDFDrive ) 1179

the world, is tomato sauce and paste The solids in tomatoes are about two-thirds flavorful sugars and organic acids, and 20% cell-wall carbohydrates that have some thickening power (10% cellulose, and 5% each pectin and hemicelluloses) In the United States, commercial tomato purees may include all the water in the original tomatoes, or just a third Tomato paste is tomato puree cooked down so that it contains less than a fifth of the water of the raw vegetable Tomato paste is thus a concentrated source of flavor, color, and thickening power (It’s also an effective emulsion stabilizer; see p 628.) There are several variables in the preparation of purees that can affect their final texture and flavor Food scientists have shown this most clearly for mass-produced tomato puree The general lessons are also relevant to the preparation of purees from other fruits and vegetables Tomato Enzymes and Consistency The final consistency of a tomato puree depends not just on how much water has been removed, but also on how long the puree spends at either moderate or high temperatures Ripe tomatoes have very active enzymes whose job is to break down pectin and cellulose molecules in the fruit cell walls, and so give the fruit its soft, fragile texture When the tomatoes are firstcrushed, the enzymes and their target molecules are thoroughly mixed together, and the enzymes start breaking down the cell-wall structures If the raw puree is held at room temperature for a while, or heated to a temperature below the denaturation temperature of the pectin enzymes, around 180ºF/80ºC, then the enzymes will break down a lot of the cell-wall reinforcements, and these liberated molecules will give a noticeably thicker consistency to the puree However, when the puree is then heated to ...Tomato Enzymes and Consistency The final consistency of a tomato puree depends not just on how much water has been removed, but also on how long the puree spends at either moderate or high... 180ºF/80ºC, then the enzymes will break down a lot of the cell-wall reinforcements, and these liberated molecules will give a noticeably thicker consistency to the puree However, when the puree is then heated to... together, and the enzymes start breaking down the cell-wall structures If the raw puree is held at room temperature for a while, or heated to a temperature below the denaturation temperature of the