Food Processing and Preservation

1. FOOD PROCESSING AND
PRESERVATION
Presented By:
Dr. Ashok Kumar Yadav
Assistant Professor (Food Proc. & Mgmt.)
DDU Kaushal Kendra
Banaras Hindu University
ashok.yadav4@bhu.ac.in

3. Introduction
I want to enjoya
mango in winter
season? Is it possible? Why not ! it ispossible

4. Food Preservation: Introduction
How it ispossible?
I will tell you how itis
possible

5. You know that mangocold
drinks available in all
season
Some food like
mango pickle is also
availablethroughout
theyear.

6. How does it not spoil when
stored for much time?

7. Do You know that howthe
food is Preserved?

8. Food Preservation
Food Preservation is a process in which:
Food and vegetables are prevented from getting
spoilt
The color, taste, and nutritive values of food is
also preserved
Food products lasts for a long period of time:
Shelf life of food product is increased

9. So, we can defined Food
Preservationas:
Retaining food over a period of time without
being contaminated by pathogenic organisms
or chemicals and without losing its colour,
texture, flavour and nutritiousvalue.
Food Preservation usually involves preventing
the growth of bacteria, fungi and other
microorganisms, as well as retarding the
oxidation of fats which causesrancidity.

10. Why to preserve foods?
Why should wepreserve
foods? I will explainit

11. Types of foods
Food Types
Perishable Semi Perishable Shelf Stable
Fruits Milk Cheese, Some
readyfoods
Grains

12. Food types
 Perishable
- Lasts for less time 2 days to 1 week
- Example: Fruits, milk, vegetables, meat
 Semi perishable
- Lasts foraround 2 monthsand are processed
- Example: Ice-cream, cheese, bread, cake,pastries
 Shelf Stable
- Has longer shelf Life more than 6months
- Example: Food grains

13. Why to preserve food?
If weareable to preserve foods, weenjoy
any kind of foods in any season
Weeat food even it isnot
available in ourareas
Wecan storeour food easilyand
withoutworries

14. Explanation of previous slide
Weenjoyany kind of food in any season and different
types. Suchas
 Mango juice
 Mango pulp
 Mango pickle
 Raw mango powderetc

15. Principles of Food Preservation
1. Inhibit thegrowthand activityof Microorganisms
-Asepsis (to keep outmicroorganisms)
-Removal of microorganisms
-Stopping the growth and activityof microorganisms
(low temperatures, drying orchemicals)
-Destruction of MO (heating orradiation)

16. Principles of Food Preservation(contd.)
2. Protecting against self decomposition offood
-Inhibit the activity of EndogenousEnzyme
(Phenolase)
-Delay or inhibit chemicalreactions (Non-enzymatic
browning)
3. Protection from invasion and spoilage by insectsand
rodents
4. Protection against losses by mechanicalcauses

17. Importance of Food Preservation:
vital in the Food industry due to a
Important and
number of -
social,
psychological, and
health factors
 Increases the shelf life of food
 Retain the quality of food – colour, texture, flavour &
nutritional value
 Increases food supply
 Adds variety to thefood
 Decreases wastage of food
 Make foods available throughout theyear

18. Food Preservation Methods
 Preservation methods vary accordingto
--------the food items,and
--------quantity of the items to be preserved
Principles of Food preservation can bebroadly
classified into twotypes:
1) Bactericidal methods
2) Bacteriostatic methods

19. Bactericidal methods:
Most of the microorganisms arekilled
Examplesare-
o cooking,
o canning,
o pasteurization,
o sterilization,
o irradiation etc.

20. Bacteriostatic Methods:
Based on prevention of multiplicationof
microorganisms
May be achieved by
----removal of water
----use of acids, oils orspices
----keeping the foodstuff in lowtemperature
Methods based on this principlesare
----Drying,
----freezing,
----pickling,
----salting, and
----smoking.

21. Techniques of Food Preservation
 Physical
 Chemical
Physical
--freezing and canning(rely on killing
the microorganisms or at least stopping
their growth for longenough)
--drying, gamma irradiation, exposure to
ultraviolet or high intensity white light,
ultra high pressure andfiltration

22. Chemical
 Preservatives
 Work eitheras:
 Direct microbial poisonsor,
 Reducing the pH toa level that prevents thegrowth of
MOs
#Chemicals used todayare:
1. Nitrates and Nitrites
----to preservemeats
2. Sulphites
----to prevent the browning of fruits andvegetables,
----to prevent fungalspoilage

23. Common food preservation methods:
 Bottling andcanning
 Pickling
 Drying
 Salting
 Vacuum packing
 Cooling and freezing
 Waxing
 Pasteurization
 Boiling
 Smoking

24. Bottling andCanning
Bottling and canning are processes of
preserving food by heating and then
sealing it in an airtightcontainer.
The food is boiled to kill microorganisms
and then sealed to prevent other
microorganismsfrom getting in.

25. Bottling Canning

26. PICKLING
Pickling food in vinegar or other acids, makes
it difficult for microorganisms tolive.
Commonly pickled food include onions,
mangoes, caronda, aonla, soya beans
andchillies.
Sugar can also be used in pickling fruits such
as nutmegs, mangoes and cherries.

27. The concentrated sugar solution used draws
water from the fruit thus preventing the
growth of microorganisms.

28. Drying
A lotof food is preserved bydrying underthe
sun.
Drying removes most water from food.Most
bacteria die or become inactive when the
food is dried.

29. Fishes, dried fruits and dried chilliesareexamplesof dried food

30. A lot of fruits such as raisins,guavas
and papayas can be eatendried.

31. Salting
Salting is an age-old way of preserving
food. The salt draws out moisture and
prevents microorganisms from
growing. In this process, food such as
fresh fish are gutted, washed and
coarse salt is rubbed intoit.

32. A lot of our local foods are
preserved by salting process.

33. Vacuum Packing
Vacuum packing keeps food bysucking
air out from itspackaging.
Food is thus prevented fromspoiling
because there is noair.

34. Vacuum packing is commonly used forstoring
nuts, sliced fish, pickled and driedfruit.

35. Cooling and Freezing
Cooling and freezing are the most
common forms of food
preservation.

36. Cooling slows down the action of
microorganisms, thus it takes longer to
spoil. It allows fruit from different parts of
the world to appear on our supermarket
shelves.(0 to -40 C)
At freezing temperature,
microorganisms become inactive, thus
food cannot spoil when it is frozen.
(-18 0C)

37. Food like meat, fruit and vegetables are kept in
the refrigerator.

38. Waxing
Waxing of fruit and vegetables is also common. Apples,
oranges, eggplants and tomatoes are dipped into liqiud
wax to preventgrowthof fungi and lossof moisture.
Waxed fruit need to bewashed thoroughlyor peeled before
eating.

39. Pasteurization
Pasteurization means heating food to a
certain temperature for some time followed
by rapid cooling. Heating at such high
enough temperature kills most bacteria.
However, it does not affect the taste and
nutritional valueof the food.

40. Fresh milk, yoghurt drink and juicesare
pasteurized to make them lastlonger.

41. Boiling
As food is heated and cooked, the heat killsthe
microorganisms,
Boiling kills most bacteria. However, those not affected by
heatwill grow when theconditions are suitable.
Boiling kills bacteria

42. Smoking
Smoking is the process of drying food with
smoke for a long period of time. This method
is mainly used for fish, meat and fruit such as
banana.
The drying effects of smoke and the chemicals
produced from the smoke help to preserve the
food.
Smoked banana Smoked meat

43. Food Processing
 Food processing is the set of methods and techniques used
to transform raw ingredients into food or to transform food
into other forms for consumption by humans or animals
either in the home or by the food processing industry. Food
processing typically takes clean, harvested crops or
slaughtered and butchered animal products and uses these
to produce attractive, marketable and often long-life food
products. Similar process are used to produce animal feed.

44. Food Processing
From Farm ToTable
?
Whey protein, aby-product
of cheese manufacturing, is
used inenergy bars and drinks!

45. Aims of Food Processing
1. To extend the shelf life toallow time for distribution,
sales and home storage.
2. To increase variety in the diet by providing a range of
attractive flavours, colours, aromas and textures in
food (collectively known as eating quality, sensory
characteristics or organoleptic quality);
3. To provide the nutrients required for health (termed
nutritional quality of a food).
4. To generate income for the manufacturing company.

46. Careers in Food Processing
 JobTitles:
 Process Engineer
 Engineer
 Employers:
 Food processors
 Ingredient
manufacturers/suppliers
 Academia (Higher Education)
 Contract research
laboratories/development
firms
 Self-employed/Consultant
 Responsibilities:
 Processdesign
 Bench-top process
development
 Testing
 Plantscale-up
 Commercialization
 Troubleshooting

47. Food Processing divided into:
 Unit operations combination of procedures to
achieve the intended changes to the raw materials.
 Unit operations are grouped together to form a
and sequence of
nature of the final
process. The combination
operations determines the
product.

48. Food Processing
 Examples of food processing methodsinclude:
 Chopping
 Mixing
 Homogenizing
 Cooking
 Pastuerizing
 Blanching
 Spray-drying
 Frying
 Baking
 Packaging
 Addition of gas such as airentrainmentfor bread or
gasification of softdrinks

49. Dehydration
 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’ (or in the case of freeze drying by
sublimation).
 The main purpose of dehydration is to extend the shelf
life of foods by a reduction in water activity. This
inhibits microbial growth and enzyme activity, but the
processing temperature is usually insufficient to cause
their inactivation.

50. Dehydration
 Drying causes deterioration of both theeating qualityand
the nutritional value of thefood.
 Examples of commercially important dried foods are
coffee, milk, raisins, and other fruits, pasta, flours
(including bakery mixes), beans, nuts, breakfast cereals,
tea and spices.
 There are a large number of factors that control the
rate at which foods dry, which can be grouped into the
following categories
 processing conditions
 nature of thefood
 drierdesign

51. Blanching
 Blanching serves a variety of functions, one of the
main ones being to destroy enzymatic activity in
vegetables and some fruits, prior to further processing
by heat. As such, it is not intended as a sole method of
preservation but as a pre-treatment which is normally
carried out between the preparation of the raw
material and later operations (particularly heat
sterilisation, dehydration and freezing.
 Blanching is also combined with peeling
cleaning of food, to achieve savings in
and/or
energy
consumption, space and equipmentcosts

52. Blanching
 A few processed vegetables, for example onions and green
peppers, do not require blanching to prevent enzyme
activity during storage, but the majority suffer considerable
loss in quality if blanching is omitted or if they are under-
blanched.
 To achieve adequate enzyme inactivation, food is heated
rapidly to a pre-set temperature, held for a pre-set time and
then cooled rapidly to nearambient temperatures.
 The factors which influence blanching time are:
• type of fruit or vegetable
• size of the pieces offood
• blanching temperature
• method of heating.

53. Pasteurisation
 Pasteurization is a relatively mild heat treatment, in which
food is heated to below 100ºC. In low acid foods (pH>4.5,
for example milk) it is used to minimize possible health
hazards from pathogenic micro-organisms and to extend
the shelf life of foods for severaldays.
 In acidic foods (pH <4.5, for example bottled fruit) it is
used to extend the shelf life for several months by
destruction of spoilage micro-organisms (yeasts or moulds)
and/or enzymeinactivation

54. Canning
 A method of preserving food by killing all
microorganisms present in the food and then sealing
out air
 The food, container and lid are heated untilsterile
 As the food cools, the lid makes an airtight seal,
preventing contamination

55. Extrusion
 A process bywhich the form of a food is changed
 Such as changing corn tocorn chips
 Not a preservationmeasure
 In this process, the food is heated, ground, and pushed
through various kinds of screens to yield different
shapes

56. Frying
 Frying is a unit operation which is mainly used to alter
the eating quality of afood.
 A secondary consideration is the preservative effect
that results from thermal destruction of micro-
organisms and enzymes, and a reduction in water
activity at the surface of the food (or throughout the
food, if it is fried in thinslices).
 The shelf life of fried foods is mostly determined by
the moisture content after frying: foods that retain a
moist interior (for example doughnuts, fish and
poultry products which may also be breaded or
battered), have a relatively short shelf life, owing to
moisture and oil migration duringstorage.

57. Irradiation
 Ionising radiation takes the form of Gama-rays
from isotopes or, commercially to a lesser extent,
from X-rays and electrons. It is permitted in 38
countries to preserve foods by destruction of
micro-organisms or inhibition of biochemical
changes.

58. The main advantages of irradiation are as follows:
 there is little or no heating of the food and therefore
negligible change to sensorycharacteristics
 packaged and frozen foods may betreated
 fresh foods may be preserved in a singleoperation, and
without the use of chemicalpreservatives
 energy requirements are verylow
 changes in nutritional valueof foodsarecomparable with
other methods of foodpreservation
 processing is automatically controlled and haslow
operating costs.

59. Chilling
 Chilling is the unit operation in which the temperature
of a food is reduced to between 1ºC and 8ºC.
 It is used to reduce the rate of biochemical and
microbiological changes, and hence to extend the
shelf life of fresh and processed foods. It causes
minimal changes to sensory characteristics and
nutritional properties of foods and, as a result, chilled
convenient, easy to prepare, high quality
foods are perceived by consumers as being
and
‘healthy’, ‘natural’ and ‘fresh’.

60. Chilling
 Chilling is often used in combination with other
unit operations (for example fermentation or
pasteurization) to extend the shelf life of mildly
processed foods. There is a greater preservative
effect when chilling is combined with control of
the composition of the storage atmosphere than
that found using either unit operation alone.

61. Freezing
 Freezing is the unit operation in which the
temperature of a food is reduced below its freezing
point and a proportion of the water undergoes a
change in state to form ice crystals. The
immobilization of water to ice and the resulting
concentration of dissolved solutes in unfrozen
water lower the wateractivity (aw) of the food.
 Preservation is achieved by a combination of low
temperatures, reduced water activity and, in
some foods, pre-treatment byblanching.

62. The major groups of commercially frozen foods are as
follows:
• fruits (strawberries, oranges, raspberries) eitherwhole or
pureed, or as juice concentrates
• vegetables (peas, green beans, sweet corn, spinach, and
potatoes)
• fish fillets and sea foods (cod, plaice, shrimps and crab
meat) including fish fingers, fish cakes or prepared dishes
with an accompanyingsauce
• meats (beef, lamb, poultry) as carcasses, boxed joints or
cubes, and meat products (sausages, beefburgers, reformed
steaks)
• baked goods (bread, cakes, fruit and meatpies)
• prepared foods (pizzas, desserts, ice cream, complete meals
and cook–freezedishes).

63. Packaging
 Food is packaged for manypurposes.
 Some reasons are:
 containment for shipping, dispensing, unitizing into
appropriate sizes, improving theusefulness,
 protect from microbial contamination, physical dirt,insect
invasion, light exposure, flavor pickup, flavor loss,
moisture pickup, moisture loss and physical abuse
 Food is packaged in metal cans, glass & plastic bottles,
paper & paper board, wide variety of plastic & metallic
films and combinations of these
 Packaging is done bycontinuous automatic machinesat a
speed of 1000 units permin.
 Thecontainer forming is dependenton the typeof the food

64. • A variety of methods are available to allow food to be safe
and could be stored for extended period of time.
• Many storage preservation and processing methods have
an effect on quality of food.
• There is no such thing of absolute safety.
• Therefore there should be balance between safety and
quality, but safety should be of primary consideration.
• Food storage is vital as it can prepare for your
emergencies and future stresses and also could fulfill our
food security.
Conclusion

65. Thank You