Non-Enzymatic Browning: Millard Reaction

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Non-Enzymatic BrowningMillard Reaction

• Nonenzymatic browning is found in food
  processing operations involving dehydration/
  condensed milk.
• Nonenzymatic browning is purely chemical and
  occurs by several mechanisms.
• The Maillard Reaction is a chemical reaction
  between an amino acid and a reducing sugar,
  usually requiring heat.

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Non-Enzymatic BrowningMillard Reaction
Reducing sugars
Amino compounds

Amines, amino acid, proteins
Glucose, Fructose, lactose, Maltose

• Temperature
• Conc. of the reactants
• pH
• Inhibitors or preservatives

Melanoidins
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Non-Enzymatic BrowningMillard Reaction

• Browning reactions may be
• - desirable to the food
• crust on baked goods, color of caramel, flavor,
  color of maple syrup
• - detrimental to the food
• darkening of dehydrated fruits , eggs,
  vegetables, canned or dried milk

4
30 min.
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2
3
4
5
6
100ºC
50? Brix invert sugar (ml) 4 4
4 4 4
4
Mix Well on a vortex mixer
10 glycine 1 1 1
1 1 1
(ml)
Read the Optical Density at 420 nm
Buffer 1 1 1
1 1 1
(ml) pH 3 pH 4 pH 5
pH 6 pH 7 pH 8
5
30 min.
7
Mix Well
1ml buffer pH 8
1ml 10 glycine
4ml 50? Brix invert sugar
70ºC
Read the Optical Density at 420 nm
6
30 min.
8
Mix Well
0.1g Sodium metabisulphate
1ml buffer pH 8
1ml 10 glycine
4ml 50? Brix invert sugar
100ºC
Read the Optical Density 420 nm
7
30 min.
9
Mix Well
1ml buffer pH 8
1ml D.W.
4ml 50? Brix invert sugar
100ºC
Read the Optical Density 420 nm
8
30 min.
Blank 10
Mix Well
1ml buffer pH 8
1ml D.W.
4ml 50? Brix invert sugar
25ºC
Read the Optical Density 420 nm
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Results
Absorbance 420 nm Tube
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Samar A. Damiati