There are many
different forms of processing to which food may be subjected before
we eat it. All of these processes have some effect on the nutrient
con tent. Although foods are often compared before and after processing,
a better comparison is at the stage when the food is eaten. For example,
during the freezing of peas there is about a 10 per cent loss of vitamin
C. But because they require a shorter cooking time than fresh peas,
there is virtually no difference between the vitamin C content of
fresh and frozen peas as they appear on our plate.
changes that occur in the commercial preparation of food do not differ
much from those in the same food prepared in the home. Both types
of food preparation involve some form of processing. There may be
differences in palatability and the food manufacturer may use cheaper
ingredients such as emulsifiers, cereal fillers and synthetic flavours.
This may be partially off-set by the fresher foods usually available
to the manufacturer. The effect of the different types of processing
on nutrients is discussed below.