loss of nutrients during processing

1. EFFECTS OF PROCESSING ON
NUTRIENTS
• MAMTA SAHURKAR
• LAXMINARAYAN
INSTITUTE OF
TECHNOLOGY, NAGPUR
• ASST PROF. SHITAL
DESHMUKH

2. WHAT IS FOOD PROCESSING???
Food processing is simply the
transformation of raw ingredients into
food.
Food processing typically takes clean,
harvested crops or butchered animal
products and uses these to produce
attractive, marketable and often long
shelf-life food products.

3. What is the need of food processing?
Once food is harvested, it begins to
deteriorate immediately due to the
following factors:
Micro-organisms (yeast, mould,
bacteria)
Intrinsic enzymes;
Temperature;
Moisture; and
Insects and vermin.

4. Food processing involves the application of
scientific principles to slow down the
natural processes of food decay caused by
micro-organisms, enzymes in the food or
environmental factors such as heat,
moisture and sunlight - and so preserve the
food.

5. Aims of food
processing
To make food safe (microbiologically,
chemically).
To provide products of the highest
quality (flavour , colour ,texture)
To make food into forms that are
convenient (ease of use)

6. Methods of food processing
Physical Methods Chemical Methods
Pasteurization Ph Balance
Frying Control Of Water Activity
Fermentation Use Of Food Additives
Baking And Cooking Intermediate Moisture
Foods (IMF)
Blanching
Irradiation
Drying
Canning
Extrusion Cooking

7. Pasteurization is the process
of heating a food usually a
liquid to or below its boiling
point for a defined period of
time. The purpose is to
destroy all pathogens, reduce
the number of bacteria,
inactivate enzymes and extend
the shelf life of a food product
Pasteurization

8. .Iodine
• The iodine content of milk varies greatly. A 20%
reduction in iodine has been reported with
pasteurization.
.Vitamin C
• Vitamin c is sensitive to heat and oxidation; thus,
losses have been reported to range from 0% to 20%
following pasteurization
.Enzymes
• In particular, pasteurization destroys enzymes that
contribute to immunity as well as the digestive
enzymes

9. • Other nutrients which are destroyed
in pasteurisation but in small
quantity are:
Fruit and milk sugar
Flavours
Natural, antimicrobial properties
Vitamin B-complex
• Only a 1% decrease in the biologic
value of protein observed following
pasteurization.

10. Frying differs from other
methods of heat processing in
that the cooking medium is hot
oil. Frying is a unit operation
which is mainly used to alter the
eating quality of a food.Thermal
destruction of micro-organisms
and enzymes, and a reduction
in water activity at the surface
of the food are secondary
advantages.
Frying

11. • Fat absorption by the food product varies from 10% to
40% depending on the time food is immersed in oil.
• causes oxidation of the oil to form a range of
volatile carbonyls, hydroxy acids, keto acids and
epoxy acids causing unpleasant flavours and
darkening of the oil.
• Oxidation of fat-soluble vitamins in the oil results in
a loss of nutritional value. Retinol, carotenoids are
each destroyed and contribute to the changes in
flavour and colour of the oil.

12. • Vitamin B and C losses occurs but are very low.
Thiamine is one of the most important vitamins
of the b group. Fortunately, thiamine losses are
lower in the case of frying, near about (30%).
• Vitamin E is lost along with the oxidation of
unsaturated fatty acids during heating.
• Vitamin A In deep fried vegetables, losses of
beta-carotene were twice as high as in shallow-
fried foods. Some beta-carotene could migrate
into the frying oil.

13. • Fermentation in food processing
typically is the conversion of
carbohydrates to alcohols and
carbon dioxide or organic acids
using yeasts, bacteria, or a
combination thereof, under
anaerobic conditions
• Fermentation usually implies
that the action of
microorganisms is desirable, and
the process is used to produce
alcoholic beverages such as
Fermentation

14. EFFECTS OF FERMENTATION
• Instead of adding nutritional benefits to the food,
fermentation decreases some vitamin and mineral
availability.
• Many fermented foods, such as soy sauce, contain
a significant amount of alcohol.
• According to research, the levels of vitamin B12
may be reduced by fermented foods.
• Another acid that results from fermentation is
lactic acid. Lactic acid is a waste product

15. • Nutrient losses in the 5-15% range.
Baking is a food cooking method using
prolonged dry heat acting by convection and
not by thermal radiation normally in an oven
but also in hot ashes, or on hot stones.
• Coagulation of proteins
• Caramelization of sugars
BAKING AND COOKING
Effects of baking and cooking
• Sometime minerals are
changed to their unusable
and poisonous inorganic
state and vitamins are
largely

16. EFFECTS OF REFRIGERATION &FREEZING
• water in foods form ice crystals which will break down
the cell structure of some foods.
• When a food is frozen, its water expands. This causes
two immediately destructive occurrences;
• The cell walls burst and the cell contents are spilled due
to the internal water expansion; hence the cell's life is
lost.
• Oxidation occurs where air reaches the frozen foodstuff;
hence nutrients are lost.

17. • Blanching is a thermal process
used mostly for vegetable
tissues prior to freezing, drying,
or canning.
• Blanching is a slight heat
treatment, using hot water or
steam
• Blanching is carried out at
temperatures close to 100° c
(212° f) for two to five minutes
BLANCHING

18. • Some minerals, water-soluble vitamins and other
water-soluble components are lost during
blanching.
• Cell tissue structure is
distorted
• Antioxidants
The researchers said 2003 "journal of the science of
food and agriculture" study as finding a 20 to 30% loss
of phenolic antioxidants after blanching
• Blanching may decrease the amount of
carbohydrate, fat and water-soluble protein in
certain vegetables.
EFFECTS OF BLANCHING

19. Irradiation
Irradiation is the controversial process of applying
low doses of gamma radiation to food products.
• Irradiation of food, like cooking (thermal treatment),
causes a loss of vitamins
• food can develop off flavours
• Irradiation can change the structure of a protein
• The loss of texture (softening) is the main draw back
from a qualitative point of view
EFFECTS OF IRRADIATION

20. • Dried foods are higher in calories.
• Dried fruits may taste sweeter than fresh fruits
due to the concentrated sugar content.
• Nutritional losses during drying are more due to
the application of heat than to the removal of
moisture. Generally, except for thiamine.
• Protein content of dried vegetable may be
greater.
drying
Dehydration (or drying) is defined as ‘the application
of heat under controlled conditions to remove the
majority of the water normally present in a food by
evaporation.
Effects of drying

21. 9.Canning
• Canning is a method of preserving food in which
the food contents are processed and sealed in an
airtight container. Canning provides a typical shelf
life ranging from one to five years.
• Canning is a high heat process
that can destroy nutrients
• Vitamins and phytonutrients are
especially susceptible to
degradation from heat.
Effects
:
• Canning has no effect on
proteins, carbohydrates and
fats.
• Mainly harm to canned food
occurs when proper sterilization
and head spacing is not done.

22. Extrusion is the process in which a food is
compressed and worked to form a semi-solid
mass. This mass is then forced through a restricted
opening, to create a desired texture or shape.
• Slight increase of iron-bioavailability
• Creation of insulin-desensitizing starches,
which are a risk-factor for developing
diabetes
• Destruction ofVitamin A (beta-carotene)
Denaturation of proteins.
EXTRUSION
EFFECTS OF
EXTRUSION

23. • Chemical methods are simultaneously
carried out with the physical methods.
• This means that the p H maintenance and
control of water activity is involved in
drying, refrigeration themselves.
• Intermediate food moisture and
preservatives are done by addition of
additives.
• There are many food additives and effect
will vary vastly with nature of additives
used.
Chemical methods

24. .…THANK YOU….