B6 - Enzymes Flashcards
What enzyme does the dairy industry use and how?
Protease ( eg rennet) causes solids (curds) to separate from the liquid (whey ) in milk
What enzyme does the food processing industry use and how?
Professes digest proteins in foods such as soy and citrus products, to remove bitter tastes.
What enzyme does the fruit juice industry use and how?
Cellulases break down cell walls in the fruit, releasing juice.
Amylases reduce cloudiness and increase sweetness by breaking down starch.
What enzyme does the medical industry use and how?
Glucose oxidase is present in kits used by people with diabetes to test for glucose in urine or blood.
What enzyme does the biological washing powder industry use and how?
Proteases, lipases and amylases remove organic stains such as food and grass stains from laundry.
How are enzymes involved in sugars and sweeteners? How is this useful to the food industry?
Processed foods and soft drinks contain a lot of sugar to sweeten the product. The sugar extracted from plants like sugar cane is called sucrose.
An enzyme called invertase (sucrase) digests sucrose into glucose and fructose. The food industry now has a much sweeter product. They can use fructose to sweeten food. This way less sugar is needed to produce a sweet product. This is common practice in producing low calorie foods and drinks.
Why do biological washing powders use enzymes?
• Enzymes digest stains.
• Enzymes digest fibres in the dirt, releasing bobbles.
• They allow stain removal to occur at a lower temperature, which saves energy and money.
The enzymes break down the stains into small soluble products that wash off the fabric. Unfortunately, the enzymes in biological washing powders don’t work at high temperatures or extreme pH levels.
What are the disadvantages of biological washing powders?
- The enzymes may be destroyed at high temperatures so do not work for a hot wash.
- The enzymes are pH sensitive, so they may not work so well in areas of the country with particularly acidic or alkaline water.
• They may cause allergies.
How do enzymes test for sugar?
The normal blood glucose level is from 4–8 mmol/l. Diabetics often experience higher levels. They monitor their blood glucose level to prevent it rising for too long, as persistent high levels can damage blood vessels in organs like the eyes. If their blood glucose level falls too low, they could become unconscious.
Testing could be done using the food test called Benedict’s test for glucose. This is not very practical in our modern lives. Now we use reagent sticks to test for glucose. These sticks make use of enzymes.
How do enzymes help lactose intolerance?
Some people don’t make the enzyme lactase, and so they cannot digest the sugar lactose in their gut. Bacteria in their digestive system digest it instead, leading to diarrhoea and wind. Enzymes are now used to produce lactose-free foods.
Why are some enzymes immobilised?
To help make enzymes more stable and easier to use.
The enzymes are immobilised, which means they are attached to a more inert substance.
How are enzymes immobilised?
The enzyme can be added to a fibre mesh, as on reagent sticks.
Another method is to produce gel beads containing the enzymes:
• The enzymes are mixed with a solution of sodium alginate.
• The mixture is dropped into a calcium chloride solution.
• This causes small beads of alginate gel to form.
• Embedded in the gel are the enzymes.
What are the advantages of using immobilised enzymes?
- The beads are easier to use than free enzymes.
- The beads support the structure of the enzyme, making it less sensitive to temperature and pH.
- The enzyme can be removed from a reaction mixture by ltering out the beads, so the solution is not contaminated with enzymes.
- The beads can be placed in a column, and the reactants poured in at the top. The products can be drawn off at the bottom of the column.
What is lactose intolerance and how are the gel beads of enzymes able to help this?
lactose intolerance means that they are unable to digest the lactose in their diet. If they eat or drink too much lactose, it can make them unwell.
Beads can be made containing immobilised lactase enzymes. These beads are then mixed with high-lactose foods such as milk. The enzyme digests the lactose into glucose and galactose:
Lactase Lactose -> glucose + galactose
Both glucose and galactose are easily absorbed in the gut.
