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Browning Reactions

Browning Reactions. FDSC400. Important Types of Browning. Enzymatic (polyphenoloxidase). Fresh cut vegetables, non-toxic, no flavor Caramelization. Sugars at very high temperatures. Lipid Browning. Polymerization of frying oils Vitamin C Browning. Similar to Maillard

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Browning Reactions

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  1. Browning Reactions FDSC400

  2. Important Types of Browning • Enzymatic (polyphenoloxidase). Fresh cut vegetables, non-toxic, no flavor • Caramelization. Sugars at very high temperatures. • Lipid Browning. Polymerization of frying oils • Vitamin C Browning. Similar to Maillard • THE MAILLARD REACTION

  3. Maillard Browning • “the sequence of events that begins with reaction of the amino group of amino acids with a glycosidic hydroxyl group of sugars; the sequence terminates with the formation of brown nitrogenous polymers or melanoidins” • John deMan

  4. The Maillard Reaction • Occurs between reducing sugars and amines at high temperatures • Produces flavor • Produces color • Produces antioxidant products • Produces toxic products • Destroys nutrients (lysine)

  5. Addition of an amine to an aldose

  6. The Amadori Rearrangement

  7. DH – A Crucial Intermediate Amines Polymerize Pyrolytic products Strecker aldehydes

  8. Sugar Pyrolytic Products maltol isomaltol

  9. Strecker Degradation Rich nutty, meaty flavors

  10. Mutagens from the Maillard Reaction Asparagine Strecker aldehyde Acrylamide

  11. Control Steps • Rapidly accelerated by temperature • Significant acceleration at intermediate water activities • Sugar type • Pentose>hexose>disaccharide>>polysaccharide • protein concentration (free amines) • Inhibited by acid • amines are protonated • and used up, pH drops • Sulfur dioxide

  12. Inhibition by Sulfite SO3- DH DSH

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