FOSC201 - Unit Operations

Steps taken to prepare food products

unit operations

putting unit operations together creates a

process

raw materials → unit operation → product

Important variables in processing

Temp (T)

time (t) '

Rate (dT/dt)

pH

composition of product

composition of atmosphere

water activity (Aw)

Transfer processes

Fluid flow - conveying, pumping

Heat transfer - heat exchange

Mass transfer - concentration, drying, cleaning

Law of conservation of mass (or energy)

material in = material out

mass of raw materials in = mass of products and wastes out + mass of stored materials + losses

Rate of transfer =

driving force/resistance

driving forces of transfer

heat transfer driving force is temp

mass transfer driving force is conc

Material flow (2 types)

Translocation - moving materials around the factory

Molecular - moving materials through unit operations

canning as a unit operation

cleaning→sorting → peeling → size reduction → mixing → filling → sealing → heat sterilization → cooling → canned product