Q. Souring of milk is due to—
Q. Souring of milk is due to
Is milk souring a physical or chemical change?
- Protozoa
- Virus
- Bacteria
- Nematode
Answer: Bacteria
Lactobacilli are anaerobic, rod-shaped bacteria that produce lactic acid by anaerobic fermentation. They are responsible for digestion of milk sugar lactose into lactic acids at suitable temperatures which in turn add a sour taste to milk.
Lactobacilli are anaerobic, rod-shaped bacteria that produce lactic acid by anaerobic fermentation. They are responsible for digestion of milk sugar lactose into lactic acids at suitable temperatures which in turn add a sour taste to milk.
Q. Souring of milk is due to
- Aerobic bacteria
- Anaerobic bacteria
- Both A and B
- None of the above
Answer: Anaerobic bacteria
The sugar is called lactose and the harmless bacteria is called lactobacillus which uses lactose for energy and creates lactic acid as a by-product. It is the lactic acid which makes milk taste sour.The speed of souring is affected by:
- temperature – the higher it is, the greater the souring effect;
- a dirty container – the presence of water, fat, dust, etc. in the milk container can double the speed of the time it takes milk to go sour.
- the weather – if you put a milk jug on the window sill during a storm, in the morning you will have home-made kefir. Scientists cannot give a precise explanation of this process, but many believe that it is caused by electromagnetic impulses.
- specific bacteria – specially created substances designed for a quicker and more effective change of milk into beneficial fermented milk products. They include kefir fungi (kefir), lactic yeast (yoghurts), propionic bacteria (cottage cheese) and lactobacillus (boiled fermented milk).
Is milk souring a physical or chemical change?
Chemical Change
No comments:
Post a Comment
What you have to say about this?