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Unformatted text preview: r less reactive than glucose (aldose) Concentration of open form Pigment formation is directly proportional to the amount of open chain Pigment form form Chemical reactions Chemical
MAILLARD BROWNING Inhibition/control of browning Lower pH and T Control a w Use non-reducing sugar Remove substrate E.g. drying of egg whites Use sulfiting agents (most common chemicals used) Add enzyme (D-glucose oxidase) prior to drying to oxidize glucose to Add glucono-δ -lactone glucono- React with carbonyls to prevent polymerization and thus pigment React formation formation Problems Degrade thiamine, riboflavin and oxidize methionine Can cause severe allergies Chemical reactions Chemical
MAILLARD BROWNING Undesirable consequences of browning 1) Aesthetically and sensorially undesirable Dark colors, strong odors and flavors 2) Formation of mutagenic compounds
Data shows that some products from the reaction of D-glucose or Dfructose with L-lysine or L-glutamic acid may demonstrate fructose mutagenicity mutagenicity 3) Leads to anti-nutritional effects
Loss of essential amino acids Primarily lysine; may be critical in lysine limited foods (cereals, grain Primarily products) products) Chemical reactions Chemical
MAILLARD BROWNING Undesirable consequences of browning (cont.) Due to its highly reactive and basic amino group lysine is most Due susceptible to Maillard browning reactions susceptible Extent of lysine degradation in milk products Milk Fresh Condensed Non-fat dry Non-fat dry ºC 100 --150 150 Time Few minutes --Few minutes 3 hours Degradation (%) 5 20 40 80...
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This note was uploaded on 03/03/2011 for the course FOS 4311 taught by Professor Kristinsson during the Spring '08 term at University of Florida.
- Spring '08