dehydration

dehydration

- getting heat intot he product and getting moisture out (mass transfer)

- drying under controlled conditions

- moisture content: around 1-5%

- importance: preservation, decrease weight and bulk, convenience items

considerations of dehydration

- surface area -> increased surface area = increased drying time

- by decreasing the distance the moisture has to take to exit the surface, the less time is will take to dry

- temperature - air properties

- air velocity - air properties

- humidity - air properties

- atmospheric pressure

- evaporation and temperature

- time and temperature

drying methods and equipment

- air convection driers

- drum or roller driers

- spray drying

air convection drieds

- drying is accomplished by heated air blown in tunnel, cabinet, or tray that contains food

drum or roller driers

- the product is dried on two heated stainless steel drums before it is scraped off

spray drying

- the product is dried as it is sprayed into a chamber with hot air