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Browning

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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  1. Browning Compiled by: Mrs. Vandana Mahajani

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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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