Lab 1: Making Your Whey With Cheese How has biotechnology - PowerPoint PPT Presentation

Lab 1: Making Your Whey With Cheese How has biotechnology influenced the food industry?

History of Cheese Making • Closely associated with the domestication of milk producing animals, such as sheep (8,000 to 10,000 years ago) • Evidence found in Egyptian tomb murals (4,000) • Widespread by the Roman Empire (25BC to 410 AD)

Bacteria and Cheese • Different cultures of bacteria are used to produce the many different flavors of cheese

The Science Behind Cheese • Bacteria produce enzymes that convert lactose (milk) to lactic acid . • Lactic acid causes the milk protein, casein , to denature and fall out of solution. • Other enzymes, called proteases , also act on casein proteins further. • Denatured casein proteins are called curds – used to make cheese.

Curdling Methods 1. Leave It To Chance Method – bacteria in the air 2. Bacterial Culture Method – buttermilk cultures 3. We Need a Cow Stomach Method – rennin enzyme 4. Genetically Trick a Fungus Method – chymosin recombinant enzyme

Leave It To Chance Method (milk + milk)

Bacterial Culture Method (milk + buttermilk)

We Need a Cow Stomach Method (milk + rennin)

Genetically Trick a Fungus Method (milk + chymosin)

Genetic Engineering

Lab Objectives • To determine which curdling agent produces cheese the fastest . • To determine which curdling agent produces the most cheese. • To examine numerical data to support predictions. • To examine variables that can lead to invalid experiments.

Lab Notebook Record the following in your lab notebook: 1. Title of the lab. 2. Describe the objectives of the lab. 3. Identify the independent and dependent variable.

Lab Notebook Record the following in your lab notebook: 4. Predict which curdling agent will produce the largest volume of cheese in the shortest amount of time. This is your hypothesis and should be written using the format provided. Explain your hypothesis. 5. Draw diagrams of the four test tubes. Include the contents and amounts of each reagent in your diagrams.

Test Tubes Label with group initials and number:

Data Table 1

Data Table 2

Data Analysis