B3 Edexcel: Yoghurt Production, Soy Sauce Production

1) Milk is heated to sterilise it, killing any bacteria already present. 

2) The mixture is stirred thoroughly to mix up the ingredients and a milk protein is added. 

3) A starter culture of Lactobacillus Bacteria is added to the mixture when it is still warm. The Lactobacillus Bacteria ferment the sugar Lactose in the milk to Lactic Acid.

4) The Lactic Acid lowers the Ph of the milk to the point where the milk proteins solidify. This is now raw yoghurt. 

5) It is then cooled and then different flavours of fruit may be added. 

6) The pots are then sealed and ready for sale. 

1) Soya beans are cooked which kills off the bacteria on their surface, and are then mixed with ground roasted wheat. 

2) Aspergillus mould is added to the mixture. The mixture is spread out on warm shallow trays and supplied with air. Enzymes produced by the mould catalyse the breakdown of the proteins and carbohydrates in the mixture. The amino acid  and sugar content of the mixture increases. 

3) Brine is added to the mixture, giving soy sauce it's salty taste. 

4) Yeasts and Lactobacillus bacteria are added to the brine mixture. The sugars in the mixture are fermented by these. 

5) Raw soy sauce is drained from the mixture. The liquid is then filtered. 

6) It is then pasteurised and stored to allow its flavours to develop

7) It is then put into sterilised bottle ready for sale.