066 FERMENTATION (LACTIC ACID)

1
066 FERMENTATION (LACTIC ACID)
To demonstrate how bacteria convert milk sugar to
lactic acid to set curd
MATERIALS REQUIRED
Two Cups, Milk Burner / Stove (to be done under
adult supervision)
2

• Take 2 cups of boiled milk Cup A with slightly
  warm milk and Cup B with bubbling hot milk (this
  should be done by the adult)?.

• Add about a quarter teaspoon of curd to both cups
  and stir the curd gently but well into the milk.
• Cover and place both cups inside a cupboard or
  away from the sun
• Note the time when the experiment was started (it
  is preferable to start the experiment in the
  morning)

warm milk
hot milk
A
Milk
Milk
B
3
(No Transcript)
4
THROUGH THIS EXPERIMENT Understand the
principles of lactic acid fermentation by
bacteria (mainly Lactobacillus sp.) from a simple
daily activity in any Indian household. Understand
if it is different from alcohol fermentation
that you observe in the balloon experiment with
sugar and yeast / bread. If it is different why
is it different? What is the role of temperature
in the process of lactic acid fermentation? Is
there a difference in the curd formation in the
two cups? If yes, why is there a difference? Does
temperature affect the milk or the microbial
action of fermentation? Learn that not all
microorganisms cause disease! Many of them help
in producing food and are beneficial to health.