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Browning. Compiled by: Mrs. Vandana Mahajani. What is browning?. Browning is a common colour change seen in food during prepreperation, processing or storage of food. Colour may range from cream or pale yellow to brown and black. Browning –desirable or undesirable.

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Browning

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Browning

Browning

Compiled by:

Mrs. Vandana Mahajani


What is browning

What is browning?

  • Browning is a common colour change seen in food during prepreperation, processing or storage of food.

  • Colour may range from cream or pale yellow to brown and black.


Browning desirable or undesirable

Browning –desirable or undesirable

  • In some cases the brown colour may add to aroma ,flavour and colour as brown crust of bread, roasted nuts, coffee beans , caramel peanut brittle etc.

  • Undesirable effects are seen in milk, cream, eggs dry fruits, coconut,citrus fruits and canned juice concentrates and milk


Types of browning

Types of browning

  • Enzymatic browning occurs in fruits when cells are disturbed when cut or bruised. This is due to the oxidative enzymes present on phenolic substances present in plant tissues.

  • Eg. Apples, brinjals, bananas, pears and potatoes

  • Phenolic compounds------oxygen----------Quonines

  • Enzymatic browning reaction

  • Prevention of EB

  • -by inactivating enzymes by heat, salt, ph levels, and low temp.

  • -by avoiding contact with oxygen


Non enzymatic browning

Non enzymatic browning

  • Maillard was the first tp observe browning . The reaction is also called protein sugar reaction.

  • Conditions favouring millard reaction

  • High temperature

  • Increase in alkalinity

  • Concentration and type of amino acid and sugar present (lysine and glucose)

  • Presence of catalyst (such as copper and iron)

  • Desirable changes are seen as in roasting of coffee beans and nuts and quality of baking bread

  • Undesirable changes like off-odour, off-colour , off-flavour can be prevented by low temp and low ph.


Caramalization

Caramalization

  • Sugars are caramalized at 163 deg C to 170 deg C.

  • This reaction occurs in sugar alone.

  • high temp

  • Sucrose----------------------------------------caramel * acid

  • decomposition

  • dehydration

  • polymerization


Ascorbic acid browning and lipid browning

Ascorbic acid browning and lipid browning

  • Ascorbic acid browning occurs in strawberry and cocum where original red colour changes to brown. The ascorbic acid present in these fruits undergoes oxidation causing browning.

  • Lime juice cordial and other preserves see this kind of browning.

  • Lipid browning occurs when amino acids present in fats react with aldehydes and reducing sugars causing browning.

  • It is an undesirable reaction


Role of browning in food preperation

Role of browning in food preperation

  • All browning reactions can be controlled.

  • Enzymatic browning is undesirable especially in cut fruits and salads.

  • Natural browning during preparation of food is desirable.

  • Brown colour, aroma and right texture imparted to food while browning occurs, is desirable.

  • Detrimental effects of browning

    . Poor colour.

    loss of nutrients

    loss of ascorbic acid.


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