Scientists work to create new and improved versions of cheese-curdling enzymes, as well as to improve the yields and qualities of cheeses. Modern-day cheese makers want to produce large amounts of high-quality cheese in the most economical way.
▪ Determine which curdling agent produces cheese the fastest. ▪ Determine which curdling agent produces the most cheese. ▪ Examine numerical data to support predictions.
▪ Examine variables that can lead to invalid experiments.
What curdling agent do you expect to produce the largest volume of cheese in the shortest time? Give a justification for your prediction.
15 mL sterile conical tube
test tube rack
Pipet, 10 mL
Pipet, 1 mL
Pipet pump, green
Pipet pump, blue
Chymosin, recombinant rennin
Graduated cylinder, 25 mL
Plastic funnels, short-stemmed
Filter paper, 12.5 cm
1. Using a 10-mL pipet and pipet pump, transfer exactly 7mL of whole milk into a labeled, 15-mL conical tube. 2. Using a 1mL pipet and pump or a transfer pipette, add .25mL (250 µL) of one of the four curdling agents into the 7mL of milk. Use buttermilk, rennin, chymosin, or more whole milk (negative control) as assigned by your supervisor. 3. Cap the tube and mix by gently inverting three times. Record this “initial time” on your data sheet. 4. Place the milk-containing portion of the tube deep into your armpit, like a thermometer, and incubate it there for at least 15 minutes. 5. Check for curdling every 5 minutes, recording the time to curdle in minutes. To check for curdling, gently tilt the tube, being careful to not break up any curds. Curds are large lumps of solidified milk. After 15 minutes,...