Irresistible "Potions": yum yum....

Lately, I'm kinda addicted to yugurts... yumm... I bet no one able to resist it, even those that hate milks like my friend, Jesse. She's in love with yugurt drinks too. Speaking of yugurt, have you ever wonder how they come around?

Yogurt, which got its name from the Turkish word "yogurur", which translates to "long life", comes in many variations. Some of these include: full cream, low fat, fat free and even organic yogurt.

Yogurt is defined as fermented acid milk, in which lactose has been transformed into lactic acid, using a microbiological system. A product with purified milk (sterilised or pasteurised) ith a variable amount of fat (whole milk, partially skimmed milk, skimmed milk), which is inoculated with selected cultures of Lactosebacillus bulgaricus and Streptococcus thermophilus, left to ferment at a temperature of about 44 degree Celsius until it coagulates and then cooled and preserved at low temperature. According to the FDA (The Food and Drug Administration), in order for a product to be called "yogurt" it must be made by combining bacteria such as Lactosebacillus bulgaricus and Streptococcus thermophilus to the dairy product.

Bacteria such as Lactobacillus bulgaricus and Streptococcus thermophilus can respire anaerobically, which converts milk sugar and lactose to lactic acid. The presence of lactic acid lowers the pH in the milk causing protein to coagulate forming curdds or yughurt. Moreover, lactic acid also restrict the growth of food poisoning bacteria. During the yogurt fermentation some flavours are produced, which give yogurt its characteristic flavour.

Lactate fermentation occurs in some bacteria. When the oxygen level is limited due to the rate of consumption exceeding the rate of supply, anaerobic respiration (lactac fermentation) occurs. Glucose is converted to pyruvated during glycolysis, generates a net gain of 2ATP and NAD+ reduced to NADH. Pyruvate is reduced to lactate by NADH and NAD+ is regenerated.

Yoghurt can easily be made at home using a live yogurt as the starter culture. To make your own yogurt use the following process:

Bring the milk to boiling point and cool down to 40-45 degree Celsius.
Pour this milk in a sterile container and about 100 mL live yogurt is added per liter milk.
Mix with a sterile spoon and incubate at 40-44 degree Celsius for 4 to 6 hours or until the yogurt is set.
Put the yogurt in teh refrigerator. if you worked under hygienic conditions, you an use your own yogurt as a starter for your next batch.