Transcript Maillard Reaction Products

Maillard Reaction
Non-Enzymatic Browning
 The
Maillard reaction is a classical browning
reaction with special implications in the food
industry
 Highly desirable
 Highly
 The
in cooking and baking
undesirable in cooking and storage
reaction can not be stopped, but can only
be limited or controlled.
Maillard Reaction
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The Maillard reaction is a browning reaction
Results from a condensation of an amino group and a reducing
sugar at its carbonyl carbon.
But aldehydes from lipid oxidation can also participate!!
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First described by Louis Maillard in 1912.
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Is catalyzed by heat, Aw, and pH.
The reaction occurs mostly during heating and cooking, but also during
storage.
Many of the reaction products are desirable, such as brown color,
caramel aroma, and roasted aromas.
 Excessive browning and development of off-flavors can affect
product quality.
Maillard Reaction Products
 Maillard
aromas are extremely complex.
 So
it is a delicate balance during heating and/or
storage that influences the reaction by-products.
 Color
develop is also an important consequence
of the reaction.
 Color development in seared meats and baked
bread is desirable while browning of dry milk,
potatoes, and other dehydrated products is
undesirable.
The International Maillard Symposium
 Since
1979, a group of global scientists have
meet to discuss Maillard topics
 Latest findings:
 Toxicity of the by-products has been found
 New
methods to inhibit parts of the reaction are
explored
 The
chemistry of high MW by-products is
unknown
What Drives the Maillard Reaction
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Temperature
 The activation energies of most chemical reactions are
over-come under most food processing conditions.
 Temperature is a major driving factor for the reaction, but
the reaction requires other contributors
 Heat, in combination with high pH and low Aw, are the
perfect criteria for the reaction.
 Reaction may be inhibited with sulfites
Anti-Nutritional Effects
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There is a trade-off for many chemical changes that occur in
foods.
Since reducing sugars and amino acids participate in the
reaction, there will be a loss of these substrates from a food
system.
Reaction products may also bind to micronutrients and
contribute to vitamin destruction or inhibit digestive enzymes.
Some reaction products may be toxic or mutagenic (ie.
pyrazines or heterocyclic amines, acrylamide).
The melanoidin pigments have been shown to inhibit sucrose
uptake in the intestine.
Progression of the Maillard Reaction
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An amino group of an amino acid (-NH2) reacts with,
An aldose or ketose sugar to form,
An N-substituted glycosylamine (colorless) plus water.
This is altered in what is known as an Amadori rearrangement to
form an N-substituted-1-amino-1-deoxy-2 ketose compound.
This is an isomerization reaction and is essential for browning
C O
C OH
HO C
C OH
C OH
C OH
Glucose
C NR
C NHR
C OH
C O
HO C
HO C
C OH
C OH
C OH
C OH
C OH
C OH
Glucosylamine
1-amino-1-deoxy-D-ketose
Creation of Just ONE by-product
C NHR
C NHR
C O
C O
HO C
C NHR
C O
-OH-
HO C
C
C OH
C OH
C OH
C OH
C OH
C OH
C OH
C OH
C OH
1,2 Eneaminol
2, 3-Enol
1-amino-1-deoxy-D-ketose
"Amadori Product"
+H2O
-remainng amino group
C O
C O
-H2O
HOH2C
CHO
O
5-hydroxymethyl-2-furaldehyde
C O
C
C
C OH
C OH
C O
-H2O
C
+Amines
C OH
C OH
C OH
3-deoxyhexosulose
"Strecker"
aldehydes
"meaty flavors"