Enzymes Lab

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Enzymes Lab the Cheese Factory Chapter 5
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Lab 4 EnzymesLearning Objectives

• Understand the chemical and biological properties
  and importance of enzymes.
• Experience the application of two different
  enzymes (one digests proteins and the other
  digests lipids).
• Review what is protein denaturation (shape
  change).
• Understand why lipid digestion requires more
  steps.

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Lab 4 Enzymespp. 43-50

• Work in Groups of 8 and Set up cheese experiment
  first. This will take the entire lab time.
• Work in Groups of 4 group lab report (4
  students per group)
• Set up bile and fat digestion experiment
• Incubate for 1 hours at 4 C, room temp., 37 C,
  or 80 C (turn on water baths).

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What is an Enzyme?
This is how an enzyme works.

• Enzymes are catalytic proteins
• Enzymes are highly specific.
• Enzyme activity is regulated.

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The Activity of Enzymes is Influenced by their
Environment

• Temperature
• Salt concentration
• pH
• Presence of other
  molecules, e.g., coenzymes
  like vitamins and
  inhibitors

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Fat Digestion

• Why bile salt/juice is helpful in complete fat
  digestion?
• What happens if one persons bile or gallbladder
  (where bile juice is stored) does not function?
• Is fat digestion faster or slower or not at all
  if digestion happens at 4C, 25C, 37C, or 80C?

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Bile and Fat Digestion
The fat/grease you eat
Nothing happens in mouth
In small intestine

• What is litmus cream?
• Cream is rich in neutral fat
• Litmus pH indicator
• Turns blue in alkaline
• Turns Red in acidic
• 4 test tubes to be set up

Can be absorbed
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• 4 tubes, one test tube brush, one pencil, one
  rack.
• Please be careful when transferring solutions
  from flasks into tubes
• Please clean the beaker used for making cheese in
  the metal sink only.
• Use test tube brushes to clean tubes and invert
  all tubes at the end.
• Use a wet paper towel to clean lab benches

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To 3 ml of Litmus Cream

• Tube 1 6 ml of dH2O
• Tube 2 3 ml of dH2O and 3 ml of bile solution
• Tube 3 3 ml of dH2O and 3 ml of lipase solution
• Tube 4 3 ml of bile solution and 3 ml of lipase
  solution
• Which group is control?

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To 3 ml of Litmus Cream

• Tube 1 6 ml of dH2O
• Tube 2 3 ml of dH2O and 3 ml of bile solution
• Tube 3 3 ml of dH2O and 3 ml of lipase solution
• Tube 4 3 ml of bile solution and 3 ml of lipase
  solution
• Record color of your tubes before and after expt.
  For comparison. Also, record the time.

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• Incubate all tubes at designated temperature (4
  C, room temperature, 37 C, or 80 C water bath)
  for one hour. (label your
  groups)
• Remove tubes and record your results.

Which group will have no digestion, partial
digestion, or complete digestion?
Before
Control, bile only lipase only
bile lipase
What will be the difference of temperature in
which the tubes are incubated?
After
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One ingredient added
Enzyme added
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How to make cheese?
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• Acidification
• 20 ml of buttermilk per liter of milk for gt4 h
  at 20 C.
• Coagulation slowly heat the mixture to 32 C.
  Setting mid range (15 min). Also label tubes
• Monitor the temp. Thermometer not touch the
  bottom. Stir
• Remove beaker from hotplate.
• Add 1 ml of rennet. Stir for 1 min. Let sit for
  30 min.
• Cutting stir the curd gently for 15 min ? whey
  released.
• Cooking heat slowly to 37-38C (do not
  overshoot). Hold for 30 min (on/off). and stir
  every 3-5 min.

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• Acidification
• 20 ml of buttermilk per liter of milk for gt4 h
  at 20 C.
• Quiz 3 (Ch 5 6)
• Coagulation slowly heat the mixture to 32 C.
  Setting mid range (15 min).
• Monitor the temp. Thermometer not touch the
  bottom. Stir
• Remove beaker from hotplate.
• Add 1 ml of rennet. Stir for 1 min. Let sit for
  30 min.
• Set up Lipase Experiment after instruction
• Cutting stir the curd gently for 15 min ? whey
  released.
• 
  Go over Quiz 3 answers
• Cooking heat slowly to 37-38C (do not
  overshoot). Hold for 30 min (on/off). and stir
  every 3-5 min.

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• Firming Let beaker sit for 1 hr. Stir every 5-10
  min.
• Draining Pour through cheesecloth (over a sink).
  Squeeze.
• Pressing Press. air dry at RT.
• Aging

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• What is whey The watery part of milk that
  separates from the curds, as in the process of
  making cheese.
• Catalyst A substance, usually used in small
  amounts relative to the reactants, that modifies
  and increases the rate of a reaction without
  being consumed in the process.
• Enzyme any of several complex proteins that are
  produced by cells and act as catalysts in
  specific biochemical reactions

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A few words about Good vs. Bad Cholesterol

• LDL Cholesterol  Less than 130 mg/dL is near
  optimal for most people. 
• More than 160 mg/dL or 130 mg/dL or above if you
  have two or more risk factors for cardiovascular
  disease
• About one-third of blood cholesterol is carried
  by high-density lipoprotein (HDL). HDL
  cholesterol is known as the "good" cholesterol
  because it gets rid of the bad cholesterol.
• Low HDL cholesterol levels (lt 40 mg/dL) increase
  the risk for heart disease.)

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Patients Lipid Profile

• Total Cholesterol 214 mg/dl
• LDL Cholesterol 134 mg/dl
• HDL Chelesterol 72 mg/dl
• Glucose 86 mg/dl
• What does it mean?