Enzymes III Flashcards
Beneficial aspects of using enzymes in food industry
- 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.
What is an immobilized 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.
Give an example for an 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.
Deleterious aspects of using enzymes in food industry
- Enzymatic browning by PPO
- Spoilage
- Safety issue
Reaction of Enzymatic browning by PPO
MONOPHENOL/DIPHENOL+ 02 –PPO O-quinone –polymerization melanin
Give an example for an enzyme that changes the texture in food spoilage
pectinase and glycosidases hydrolyze the pectin and starch - soft texture
EX: banana
Give 3 example for an enzyme that changes the flavour in food spoilage
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,
Which enzyme gives rancid odour?
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.
Which enzymes causes bitter taste in food?
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,
Why is using enzymes a safety issue?
♣ Histidine —histidine decarboxylase histamine + CO2
Histamine is toxic and gives an off-odor.
How are desirable effects and undesirable effects relative? Give examples for some undesirable effects used as desirable effects
- PPO –> black tea, coffee
- LOX –> blanching flour by degrading pigments
- Lipase –> flavor
- Protease –> flavor
Sources of industrial enzymes
- Plant
- Animal
- Microbial
Plant sources of enzymes
∇ (3-5%) ∇ protease ∇ papain – papaya ∇ ficin – fig ∇ bromelain – pineapple
What is the percentage of plant sourced enzymes used in food industry?
3-5%
______ comes from papayas
papain
______ comes from figs
ficin
______ comes from pineapples
bromelain
Animal sources of enzymes
∇ (6-7%) ∇ digestive protease ∇ trypsin ∇ chymotrypsin ∇ rennet
What is the percentage of animal sourced enzymes used in food industry?
6-7%
Give examples for animal sourced of enzymes
∇ digestive protease
∇ trypsin
∇ chymotrypsin
∇ rennet
Microbial sources of enzymes
∇ 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
