1. FOOD ENZYMES

2. What is an enzyme? A biological catalyst that promotes and speeds up a chemical reaction without itself being altered in the process. A biological catalyst that promotes and speeds up a chemical reaction without itself being altered in the process. Lowers the activation energies of a substance Lowers the activation energies of a substance

3. Energy Profile reactants products H EAEA T.S. catalyst

4. Enzymatic Reactions Enzyme combines with a specific substrate to a form an enzyme- substrate complex in a lock and key concept before forming new products. Enzyme combines with a specific substrate to a form an enzyme- substrate complex in a lock and key concept before forming new products.

5. Enzyme action enzyme substrate products

6. Structure of an enzyme Contains both a protein and a nonprotein. Contains both a protein and a nonprotein. Nonprotein is either a coenzyme (usually a vitamin) or a cofactor (usually a mineral). Nonprotein is either a coenzyme (usually a vitamin) or a cofactor (usually a mineral).

7. Factors influencing enzyme activity Operate under optimum conditions of pH and temperature. Operate under optimum conditions of pH and temperature. Easily inactivated (denatured) in presence of inhibitors. Easily inactivated (denatured) in presence of inhibitors.

8. Enzyme Nomenclature Names usually end in –ase. Names usually end in –ase. Usually named after substrates they act upon e.g. urea --- urease Usually named after substrates they act upon e.g. urea --- urease lactose --- lactase lactose --- lactase or the resulting type of chemical reaction e.g. hydrolysis --- hydrolases or the resulting type of chemical reaction e.g. hydrolysis --- hydrolases oxidation --- oxidases oxidation --- oxidases This rule does not always apply. E.g. ficin found in figs and papain in papayas. This rule does not always apply. E.g. ficin found in figs and papain in papayas.

9. Enzyme Nomenclature cont. hydrolysis --- hydrolases hydrolysis --- hydrolases oxidation --- oxidases oxidation --- oxidases This rule does not always apply. E.g. ficin found in figs and papain in papayas. This rule does not always apply. E.g. ficin found in figs and papain in papayas.

10. Properties of enzymes Control ripening. Control ripening. Cause food spoilage (rotting). Cause food spoilage (rotting). Responsible for changes in flavor, color, texture and nutritional properties. Responsible for changes in flavor, color, texture and nutritional properties. Can be inactivated by heat to extend storage stability of foods. Can be inactivated by heat to extend storage stability of foods.

11. Properties Used for fermentation purposes in foods. Used for fermentation purposes in foods. Can be immobilized to a surface of a membrane or other inert object in contact with the food being processed. Can be immobilized to a surface of a membrane or other inert object in contact with the food being processed. Can be extracted and purified to a high degree. Can be extracted and purified to a high degree.

12. Applications in food industry Carbohydrases: production of corn syrups from starch (glucoamylase); conversion of cereal starches into fermentable sugars in malting, brewing, distillery, baking industry (amylase). Carbohydrases: production of corn syrups from starch (glucoamylase); conversion of cereal starches into fermentable sugars in malting, brewing, distillery, baking industry (amylase). Proteases: meat tenderizers (bromelin, papain, ficin) Proteases: meat tenderizers (bromelin, papain, ficin) Lipases: Flavor production in chocolate and cheese Lipases: Flavor production in chocolate and cheese

13. Applications Glucose oxidase: desugaring of eggs, flour and potatoes; preparation of salad dressings. Glucose oxidase: desugaring of eggs, flour and potatoes; preparation of salad dressings. Pectinases: clarification of fruit juices; increase of yield of juice from grapes and other products; removal of excess pectin from juices before concentration. Pectinases: clarification of fruit juices; increase of yield of juice from grapes and other products; removal of excess pectin from juices before concentration.

14. Applications contd Lipoxygenase: bleaching of flours. Lipoxygenase: bleaching of flours. Phosphatase: quality testing of food products Phosphatase: quality testing of food products Phenol oxidase: imparts the characteristic dark hue to tea, cocoa, coffee and raisins. Phenol oxidase: imparts the characteristic dark hue to tea, cocoa, coffee and raisins. Renin (chymosin): cheese production Renin (chymosin): cheese production

15. Applications Flavorases: restoration and enrichment of flavor by addition of enzyme preparations to food products e.g. fresh corn enzyme extracts to improve flavor of cannned goods or addition of alliinase to convert alliin of garlic into garlic oil. Flavorases: restoration and enrichment of flavor by addition of enzyme preparations to food products e.g. fresh corn enzyme extracts to improve flavor of cannned goods or addition of alliinase to convert alliin of garlic into garlic oil.