CORE AREA 1 FOOD STUDIES Condensed milk Sweetened, concentrated milk used for making caramel.
Process Milk is homogenised, pasteurised and 15% sugar is added. It is then evaporated to one- third of its volumne, cooled and sealed into cans.
Effects • Pathogenic bacteria are destroyed • Shelf life is extended (approximately one year if unopened)
• Loss of vitamin C and B-group vitamins • Flavour is altered, as lactose becomes sweeter on heating and sugar is added • Increased kilocalorie and carbohydrate content due to sugar added
Evaporated milk Unsweetened, concentrated milk. Mainly used as a cream substitute.
Process Milk is pasteurised, evaporated to half its volume then homogenised. It is then sealed into cans and sterilised at 115°C for 20 minutes.
Effects • Pathogenic bacteria are destroyed • Shelf life is extended (approximately one year if unopened)
• Loss of vitamin C and B-group vitamins • Flavour is slightly altered, as lactose becomes sweeter on heating
Dried milk
Process Milk is homogenised and pasteurised. It is then evaporated to 60% of its volume and dried to form a powdered milk. This can be done by either roller drying or spray drying. Roller drying
Spray drying
Milk is poured onto heated rotating metal rollers that dry the liquid milk to a powder. The milk powder is then scraped off the rollers, cooled and packaged in airtight containers.
Blade Milk Hot air production Milk powder Double drum
Hot air chamber
Milk powder
Powdered milk
collected
Effects • Roller-dried milk does not reconstitute easily when stirred with water
• Pathogenic bacteria are destroyed
• Spray-dried milk reconstitutes easily when stirred with water
• Does not taste the same as fresh milk
• Some loss of B-group vitamins and amino acids • Long shelf life due to water extraction (2–10 years)
120 Complete Home Economics Milk powder Turbine Milk is sprayed Blade
Milk is sprayed into a hot air chamber (165°C) that instantly evaporates the water in the milk, forming a powder that falls to the bottom of the chamber. The milk powder is cooled and packaged in airtight containers.
