yoghurt production

Question 1

step 1

Answer 1

milk is heated to 85-90 degrees celcius to destroy pathogenic bacteria

Question 2

step 2

Answer 2

milk is hemogenised to break down the fat into tiny droplets - this gives a smooth consistent texture

Question 3

step 3

Answer 3

cooled to 43 degrees celcius before inoculating with a starter culture (lactobacilius bulgaricus, streptococcus thermophilus

Question 4

step 4

Answer 4

mixture is held at 42 degrees celcius to allow fermentation, this allows bacteria to ferment the lactose in the milk and produce lactic acid

Question 5

step 5

Answer 5

the lactic acid denatures and coagulates the mil proteins making it semi solid

Question 6

step 6

Answer 6

when the pH reaches 4.5 the yoghurt is cooled to 7 degrees celcius. this stops the fermentation process

Question 7

step 7

Answer 7

yoghurt may be flavoured at this stage

Question 8

what are the nutritional effects?

Answer 8

-fermentation can enhance digestibility and may increase probiotic content
-potential loss of heat-sensitive nutrients (e.g. B vitamins during heating
-some varieties may include added sugar or thickeners, altering nutritional profile.

Question 9

what are the sensory effects?

Answer 9

-lactic acid gives yoghurt a tangy, sour flavour
-fermentation thickens the texture
-optional additions (e.g. fruit, flavourings) affect taste and appearance