Pigments fromNon Enzymatic Browning

Browning Reactions (Non Enzymatic)1. Caramelization

sugar brown pigments + high temperature flavours

•2. The Maillard Reactionreducing sugar + amino acid brown pigments

+ flavours

3

Caramel Color

Produced from heat treatment of:

Sugars Alkali Acids Salts

Glucose Ammonium hydroxide. Acetic acid. Ammonium, sodium, Fructose Calcium hydroxide Citric acid potassium carbonate, Lactose Potassium hydroxide. Phosphoric acid bicarbonate

Malt Syrup Sodium hydroxide. Sulfuric acid.. Phosphate (including Molasses Sulfurous acid dibasic phosphate and Starch Hydrolysates monobasic phosphate),

Caramelization

Caramel pigments

Glucose syrup partialyneutralized pH 4

Caramel coloids

highest rate of caramelization reaction is followed by sucrose at80C to 110CCommercial liquid caramel color should have a pH of 5 to give good stability.

Classes of caramel :I. Plain caramel, caustic caramelII. Caustic sulfite caramel III. Ammonia caramel,

baker's caramel, confectioner's caramel,beer caramel

IV . Sulfite ammonia caramel, acid-proof caramel, soft-drink Caramel. Mild caramel for cola beverage

http://www.inchem.org/documents/jecfa/jecmono/v20je11.htm

which of the 4 caramel colors will work best incertain applications.1. tinctorial power (color strength), 2. pH 3. Baume (a measureof liquid density or solids level).4. Taste and odor (mix more than 1 caramel)

caramel color with the wrong ionic charge cause color precipitation or flocculation

Class I slightly negative charge. Class II and IV which have sulfites strongly negativeClass III, which has only ammonium strongly positive.

Colloidal charge is strongly affected by pH.By changing the pH of caramel solutions, the isoelectricpoint (where the charge is neutralized) can be reached

Mixing Class I, II or IV can be not have an ionic haze or precipitation.

Maillard Reaction

Neutral pHAcidic pH

No reaction occured, N has already react with H+

Steps in Maillard Reactions

(1) sugar-amine condensation and the Amadori rearrangement. no browning occurs

(2) sugar dehydration and fragmentation, and amino aciddegradation via the Strecker reaction especially at high temperatures a beginning of flavor formation -depending on which flavor is studied.

(3) formation of heterocyclic nitrogen compounds. Browning occurs at this stage.

Maillard reactionA

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Rea

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gem

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Strecker Degradation

Need : dicarbonyl and amino acidsL-lysin (nutritional amino acid) lostPyrazine is flavor compounds

Thermal damage marker

Maillard Reaction Products

Heating of food containing carbohydrate and amino acid causes the destruction of essential amino andthe decrease the bioavailability,Lysine decreases till 50%,

Examples : breakfast cereal products can decrease from 20-54%

Other effects of consumption of a diet rich in MRPs resulted in the decreasing of absorption and digestibility of protein.47% higher nitrogen fecal excretion12% lower apparent nitrogen and6% lower nitrogen digestibility

Some MRPs (maillard reaction products) can bind mineral

Factor affecting Maillard reactions1.Water contentwater is essential affect the rate reactions

2.pH•the rate and extent of browning increases with increasing pH •The reaction generally has a minimum is at pH 3. •At a pH < 3 and > 9, other nonenzymic interactions (i.e. sugar-sugar and protein-protein) compete with the Maillard reaction. •an optimum above pH 7 which is also above the typical pH for most candy products.

Neutral pHAcidic pH

No reaction occured, N has already react with H+

3.Temperature

The higher the temperature the greater browning

4.Oxygen

Give little effect

5.Metal Ion

Cu(I), Cu(II) and Fe(II), Fe(III) speed up the reactions

Example of maillard products