Food Processing and PreservationPresentation Transcript
Food processing is the transformation
of raw ingredients into food, or of food
into other forms.
Food processing is typically a mechanical
process that utilizes large
mixing, grinding, chopping and
emulsifying equipment in the production
Food processing typically takes
clean, harvested crops or butchered
To produce attractive, marketable and
often long shelf-life food products
ADVANTAGES OF FOOD
1. Toxin removal
3. Easing marketing and distribution
4. Increasing food
consistency, improves taste
5. It increases yearly availability of many
6. Enables transportation of delicate
perishable foods across long
7. Makes many kinds of foods safe to
eat by de-activating spoilage and
8. Large profit potential for
RISKS AND DISADVANTAGES
1. Loss of nutritive value
2. Possible Contamination
• physical ( hair, metals,fingernails,stones)
• chemical (excess
salt, sugar, acids,cleaning agents
• Microbial (Salmonella, E.
Nearly every food preparation process
reduces the amount of nutrients in food. In
particular, processes that expose foods to
high levels of heat, light, and/or oxygen
cause the greatest nutrient loss. Nutrients
can also be "washed out" of foods by fluids
that are introduced during a cooking
process. Similar losses also occur when
you broil, roast, or fry in oil, and then drain
off the drippings
FACTORS TO BE CONSIDERED
Hygiene, e.g. measured by number of micro-
organisms per ml of finished product
Energy efficiency measured e.g. by “ton of
steam per ton of sugar produced”
Minimization of waste, measured e.g. by
“percentage of peeling loss during the peeling of
Labour used, measured e.g. by ”number of
working hours per ton of finished product”
Minimization of cleaning stops measured e.g. by
“number of hours between cleaning stops”
Food preservation is the process
of treating and handling food to
stop or slow down food
spoilage, loss of quality, edibility
or nutritional value and thus allow
for longer food storage.
METHODS OF PRESERVING FOOD
- one of the most ancient food preservation
techniques, which reduces water activity
sufficiently to prevent bacterial growth.
- preserves food by slowing down the growth
and reproduction of micro-organisms and
the action of enzymes which cause food to
3. Freezing- (0 to -17 C)
A vacuum environment, usually in an air-
tight bag or bottle strips bacteria of oxygen
needed for survival, slowing spoiling.
Vacuum-packing is commonly used for
storing nuts to reduce loss of flavor from
5. Addition of salt/ curing
Salt draws water through Osmosis, Prague
powder(NaNO2 + Salt) gives it a distinctive
Chemical components from the smoke of
a. Nitrogen oxides form nistrosamines with
meat and fish
8. ArtificiaL Food Additives
Common antimicrobial preservatives include calcium
propionate, sodium nitrate, sodium nitrite, sulfites
(sulfur dioxide, sodium bisulfite, potassium hydrogen
sulfite, etc.) and disodium EDTA. Antioxidants include
BHA and BHT. Other preservatives include
formaldehyde (usually in solution), glutaraldehyde (kills
insects), ethanol and methylchloroisothiazolinone.
10. Irradiation ( exposure to Xrays, gamma rays)
11. High Pressure processing
12. Burying in the Ground(lack of
light, oxygen,lowpH,cool temp, dessicants in
13. Biopreservation (addition of LAB)
a. Chemical (brine,vinegar, oil)
b. Fermentation (lactic acid produced by the food
15. Addition of Lye
-NaOH prevents bacterial growth, saponifies
16. Canning and Bottling
These are substancesadded to food
to preserve flavor or enhance its
taste and appearance.
a. Intentional(added on purpose)
b. Incidental (unintentional)
Acids -added to make flavors "sharper", and
also act as preservatives and antioxidants.
Common food acids include vinegar, citric
acid, tartaric acid, malic acid, fumaric
acid, and lactic acid.
Acidity regulators are used to change or
otherwise control the acidity and alkalinity of
Anticaking agents keep powders such as
milk powder from caking or sticking.
Antifoaming agents reduce or prevent
foaming in foods.
Antioxidants such as vitamin C act as
preservatives by inhibiting the effects of
oxygen on food, and can be beneficial to
Bulking agents such as starch are additives
that increase the bulk of a food without
affecting its taste.
Food coloring are added to food to replace
colors lost during preparation, or to make
food look more attractive.
Color retention agents are used to preserve
a food's existing color.
Emulsifiers allow water and oils to remain
mixed together in an emulsion, as in
mayonnaise, ice cream, and homogenized milk.
Flavors give food a particular taste or
smell, and may be derived from natural
ingredients or created artificially.
Flavor enhancers enhance a food's existing
flavors.They may be extracted from natural
sources (through distillation, solvent
extraction, maceration, among other methods)
or created artificially.
Flour treatment agents are added to flour to
improve its color or its use in baking
Glazing agents provide a shiny appearance
or protective coating to foods.
Humectants prevent foods from drying out.
Preservatives prevent or inhibit spoilage of
food due to fungi, bacteria and other
Stabilizers thickeners and gelling
agents, like agar or pectin(used in jam for
example) give foods a firmer texture.While
they are not true emulsifiers, they help to
Sweeteners are added to foods for
flavoring. Sweeteners other than sugar are
added to keep the food energy (calories)
low, or because they have beneficial effects
for diabetes mellitus and tooth decay and
Thickeners are substances which, when
added to the mixture, increase its viscosity
without substantially modifying its other
Mercury in fish
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Department of FoodTechnology, University
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and industry literature
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