High Fructose Corn Syrup Alex Huhn CBE 555

How It’s Made  Starch isolated from corn through physical separations  Starch is acidified and treated with enzymes to reduce to glucose syrup  Glucose syrup is sent through filters and purifying processes  Glucose is isomerized to fructose

Chemical Structures of Sugars  Glucose  Cyclic hexose sugar, source of energy in glycolysis  Fructose  Constitutional isomer (same formula, different molecular shape) of glucose  Sucrose (table/cane/beet sugar)  50% fructose, 50% glucose  Fructose and glucose linked by glycosidic bond  High Fructose Corn Syrup  42% fructose (58% glucose) or 55% fructose (45% glucose)  Fructose and glucose unbound in solution

Why Do We Consume HFCS?  Sweetness  Replacement for fat  Taste loss in low-fat products fixed by addition of HFCS  Corn subsidies create surplus  Begun around 1970 by Nixon  Makes corn syrup incredibly cheap relative to table sugar  Extends shelf life of products

Glucose Metabolism  Glucose not used in cells is sent to liver (right)  Most glucose is stored as glycogen for future energy  Small amount of glucose undergoes de novo lipogenesis  Insulin triggers in presence of glucose  Tells brain to stop eating

Fructose Metabolism  All fructose is sent to liver  Uric acid increases, leading to higher blood pressure  No glycogen storage means more de novo lipogenesis  Insulin is not activated and ghrelin is not suppressed, ultimately contributing to increased appetite

References  Slide 2   Slide 3   Slide 4   Slide 6    Slides 7-8  “Sugar: The Bitter Truth” :