Enzymes III

• Natural, non-toxic • Specificity uniform products • Efficient small amount under mild reaction conditions • Enzymes can be inactivated by heating or pH. Treatment after desired catalysis achieved. • Enzyme can be recovered and reused. ∇ “immobilized enzyme” – protein is hydrolyzed by trypsin. So the enzymes are immobilized on resin or on some other material. We want to hydrolyze the protein by trypsin to get protein hydrolytes. For hydrolysis we need to inactivate trypsin bc otherwise we will get amino acids. So we kill trypsin. But if we want to recover trypsin, we immobilize it by resin or some other material so that we use centrifugation to separate them and reuse the enzyme.

• provide increased resistance to changes in conditions such as pH or temperature. • It also lets enzymes be held in place throughout the reaction, following which they are easily separated from the products and may be used again • a far more efficient process and so is widely used in industry for enzyme catalysed reactions.

∇ protein is hydrolyzed by trypsin. So the enzymes are immobilized on resin or on some other material. We want to hydrolyze the protein by trypsin to get protein hydrolytes. For hydrolysis we need to inactivate trypsin bc otherwise we will get amino acids. So we kill trypsin. But if we want to recover trypsin, we immobilize it by resin or some other material so that we use centrifugation to separate them and reuse the enzyme.

• Enzymatic browning by PPO • Spoilage • Safety issue

MONOPHENOL/DIPHENOL+ 02 –PPO O-quinone –polymerization melanin

pectinase and glycosidases hydrolyze the pectin and starch - soft texture EX: banana

lipoxygenase (LOX) catalyzes the oxidation of unsaturated fatty acids causing odor in foods. EX: beans – beany flavor Unsaturated fatty acids + O2 -LOX fatty acid hydroperoxide lipase: cause rancid odor triglycerides + O2 –lipase glycerol + fatty acids fatty acids are not stable molecules so they can easily get oxidized and give rancid odor. Protease: may form bitter peptides in protein foods. If we add more protease it breaks down the molecule to amino acids giving more flavor the food. So in this case you add more protease. However, intensive hydrolysis using protease for de-bitterness,

lipase: cause rancid odor triglycerides + O2 –lipase glycerol + fatty acids fatty acids are not stable molecules so they can easily get oxidized and give rancid odor.

Protease: may form bitter peptides in protein foods. If we add more protease it breaks down the molecule to amino acids giving more flavor the food. So in this case you add more protease. However, intensive hydrolysis using protease for de-bitterness,

♣ Histidine —histidine decarboxylase histamine + CO2 Histamine is toxic and gives an off-odor.

• PPO –> black tea, coffee • LOX –> blanching flour by degrading pigments • Lipase –> flavor • Protease –> flavor

• Plant • Animal • Microbial

∇ (3-5%) ∇ protease ∇ papain – papaya ∇ ficin – fig ∇ bromelain – pineapple

3-5%

papain

ficin

bromelain

∇ (6-7%) ∇ digestive protease ∇ trypsin ∇ chymotrypsin ∇ rennet

6-7%

∇ digestive protease ∇ trypsin ∇ chymotrypsin ∇ rennet

∇ It is the most common source of enzymes (80-90%) ∇ They grow fast ∇ They need only limited spaces and nutrients ∇ Cheap to grow ∇ Protease cocktail ∇ Transglutamniase ∇ Amylase

80-90%

∇ They grow fast ∇ They need only limited spaces and nutrients ∇ Cheap to grow

∇ Protease cocktail ∇ Transglutamniase ∇ Amylase