On food and cooking the science and lore of the kitchen ( PDFDrive ) 1507

— but they have been transformed from an acutely irregular cis geometry to a more regular trans structure (see illustration, p 799) Cis is Latin for “on this side of,” and trans for “across from”; the terms describe the positions of neighboring hydrogen atoms on the double bond between carbon atoms Because the trans fatty acids are less kinked, more like a saturated fat chain in structure, they make it easier for the fat to crystallize and so make it firmer They also make the fatty acid less prone to attack by oxygen, so it’s more stable Unfortunately, trans fatty acids also resemble saturated fats in raising blood cholesterol levels, which can contribute to the development of heart disease (p 38) Manufacturers will soon be required to list the trans fatty acid content of their foods, and they’re beginning to implement other processing techniques that harden fat consistency without creating trans fatty acids Fats and Heat Fats and Heat Most fats do not have sharply defined melting points Instead, they soften gradually over a broad temperature range As the temperature rises, the different kinds of fat molecules melt at different points and slowly weaken the whole structure (An interesting exception to this rule is cocoa butter, p 705) This behavior is especially important in making pastries and cakes, and it’s what makes butter spreadable at room temperature butter, p 705) This behavior is especially important in making pastries and cakes, and it’s what makes butter spreadable at room temperature Melted fats do eventually change from a liquid to a gas: but only at very high temperatures, from 500º to 750ºF/260– 400ºC This high boiling point, far above water’s, is the indirect result of the fats’ large molecular size While they can’t form hydrogen bonds, the carbon chains of fats do form weaker bonds with each other(p 814) Because fat ... This high boiling point, far above water’s, is the indirect result of the fats’ large molecular size While they can’t form hydrogen bonds, the carbon chains of fats do form weaker bonds with each other(p 814) Because fat... different points and slowly weaken the whole structure (An interesting exception to this rule is cocoa butter, p 705) This behavior is especially important in making pastries and cakes, and it’s what makes butter...Fats and Heat Most fats do not have sharply defined melting points Instead, they soften gradually over a broad temperature range As the temperature rises, the different kinds of fat molecules melt