This ppt is for study purposes and the aim is to benefit Dairy and Food Technology students. Various pictures are used to make topics clear. Freezing is one of the integral operations in the making of ice cream as it affects the quality, palatability, and yield of the finished product. Ice cream is almost complete food. The mix usually contains more than 60 per cent water. As ice is frozen, the ice crystals are suspended in the water, and very small air cells are incorporated into the mixture. Ice cream contains a considerable quantity of air, up to half of its volume which gives the product its characteristic lightness. Without air, ice cream would be similar to a frozen ice cube. Hope this ppt shall help students.

1. COLLEGE OF DAIRY AND FOOD TECHNOLOGY
SUBMITTED TO Dr. SEEMA TANWAR
MADAM
MANVIK JOSHISUBMITTED BY

2. CLASSROOM
PRESENTATION
ON
‘ICE CREAM MAKING EQUIPMENTS’

3. •Freezing is one of the integral operations in the making of ice
cream as it affects the quality, palatability and yield of the
finished product.
•Ice cream contains a considerable quantity of air, up to half of
its volume which gives the product its characteristic lightness.
Without air, ice cream would be similar to a frozen ice cube.

4. PRINCIPLE
The temperature of the mix which is put into
the freezer drops very rapidly while sensible
heat is being removed and before any ice
crystals are formed.
 The agitation reduces the viscosity by partly
destroying gel structure and also hastens air
incorporation.

5. FREEZING IN PARTS
 In the first stage, mix with flavour and color is
passed through freezer to get desired overrun.
Here air in incorporated with continuous
agitation.
In order to get desired consistency (in some
varieties) ice cream is hardened (without
agitation).

6. •The mix with the proper amount of color and flavoring
materials generally added at the freezer, is quickly
frozen while being agitated.
•Air incorporation is done in such a way as to produce
and control the formation of small ice crystals which is
necessary to give smoothness in body and texture,
palatability and satisfactory overrun in the finished
product.
•When ice cream is partially frozen to a certain
consistency it is drawn from the freezer into packages
and quickly transferred to cold storage rooms where the
freezing and hardening is completed without agitation.

7. Ice cream is an almost complete food. The mix is usually contains more than 60
per cent water. As ice is frozen, the ice crystals are suspended in the water, and very
small air cells are incorporated into the mixture.
 When the drawing temperature is -5.6ºC about 50 per cent of the water in mixes is
frozen. This means that in a mix having 38 percent total solids, the semi frozen ice
cream extruded will have 69 per cent of its contents as solids suspended or dissolved
in the remaining water, which amounts to only 31 percent of the whole.
 If freezing continued to a drawing temperature of -9.4ºC where 67 per cent of
water is frozen out. As ice crystals are formed, they add to the solids already in the
mix, and this increases viscosity and motor load requirements

8.  To prevent coarse, icy ice cream, the product temperature should not
be permitted to rise, but should not be lowered continuously until well
hardened.
 When hardened to -15ºC, about 80 per cent of the water is frozen. If
the temperature goes up to -14°C, about 78.5 percent of the water is
still frozen; this one degree difference results in about1.9 per cent of
the ice being melted.
 The freezing point curve shows that temperatures should be lowered
continuously, that fluctuations cause iciness, and that at lower
temperatures, there is a diminished effect.

9. a) To freeze a portion of the water of the mix to get a smooth
product.
b) To incorporate a predetermined amount of air uniformly
into the mix to get proper overrun.
c) To mix fruits and flavoring into the mix while being frozen

10. •Fast freezing is essential for a smooth product, because ice
crystals that are formed quickly are smaller than those formed
slowly.
•Therefore, it is desirable to freeze and draw from the freezer
in as short time as possible. The freezing time and temperature
are affected by the type of freezer used.

11. • Batch freezer: {Horizontal, direct expansion type}
• Continuous freezer: {Horizontal, direct expansion
type}
• Soft– serve freezer: {Batch and automatic continuous
freezers of the direct expansion type}

12. White mountain freezer

15. Changes during freezing

17. •Batch freezers are used in very small ice cream factories.
• Each batch must be measured, colored and flavored separately.
•These are of following types
the brine type; the salt and ice type; direct – expansion type(using
ammonia or Freon as refrigerant), including vertical, horizontal,
and single-, triple -, and quadruple – type freezers. horizontal
cylinder type with the freezing cylinder refrigerated with one of
the halo carbon refrigerants, most often being R-22 or R-502.

18. Batch freezers

19. • There is a mix supply tank located above the freezing cylinder, so
that mix will flow by gravity into the cylinder when a valve is
opened.
• The usual procedure is to charge the freezer, turn on the dasher
and start the refrigeration.
• A slide or pivot on the bottom portion of the front door allows the
ice cream to be drawn in to containers or bulk cans.

23. • The dasher is designed to propel the product toward the
discharge port.
• Subsequent batches are put into the mix supply tank as soon as
the previous charge is dropped into the freezing cylinder.
• Ice cream can be made by every 6-7 min by experienced
operators.
• Ice cream made with batch freezers has both larger ice crystals
and bigger air cells than ice cream made with the same mix on
continuous freezers.
• Flavours, fruits, and nuts are added to the batch in the freezer
just before it is drawn.

25. • The process consists of continually feeding a metered amount of ice
cream mix and air into one end of the freezing chamber.
• As the mixture passes through the freezing chamber it is agitated and
partially frozen and then discharged in a continuous stream of about the
same consistency usually obtained from a batch freezer.

26. CONTINUOUS ICE CREAM MAKING MACHINE

27. o This partially frozen stream is delivered into
packages, which are then placed in the hardening
room to complete the freezing process.
o One major difference in continuous processing is
that freezing is done under pressure.

28. • In the continuous freezer, following mix processing,
the mix is drawn into a flavor tank where any liquid
flavors, fruit purees, or colors are added.
• A mixture of the ice-cream mix and a controlled
volume of air is pumped under pressure into one or
more horizontal jacketed tubes, each provided with a
rotating dasher and scraper.

29. • The mix is chilled to a temperature of about -
6.1°C and is slowly and continuously forced out of
a vertical discharge tube directly into the final
containers.
• The mix then enters the dynamic freezing
process which both freezes a portion of the water
and whips air into the frozen mix.
• Mix is pumped through this freezer and is drawn
off the other end in a matter of 30 seconds.

30. Working

31. • Less use of stabilizer- large amount of ice
crystals formed- less viscosity needed.
• Shorter ageing time- less air incorporation.
• Less flavor material is needed- smaller ice
crystals melt rapidly- slightly more pronounced
flavor .
• Smoother ice cream.
• Small lactose crystals- less sandiness.

32. • Scrape the frozen film from the cylinder wall,
carry it to the centre and circulate it from one
end to other for rapid and uniform cooling
• To beat the mix and whip air into it
• To eject the frozen mix rapidly
• 170rpm to 250rpm
• Outer frame carrying 2/ more sets of scraper
blades rotate in one direction
• Central part- beater- whipping- longitudinal
rods/ paddles that rotate in opposite direction
DASHERS

33. DASHER

34. CONTINUOUS FREEZER

40. Current Scenario
• Currently, most of the large scale industries use
continuous freezers.
• Modern concept given by Clarence Vogt, in
1926 which reduced labor, utility costs and
increased production volume.
• Brands which are omnipresent are Matrix, Gram
Equipment, ROKK,Technogel,Tekno-
Ice,WCB,Soren, Tetra Pak, Gel mark,
Tecnofreeze,Catta 27and Technology.
• Growing @ 6.9% the industry has good future
scope.

42. VOGT FREEZER
The principle of operation of Vogt freezer is same as that of the
disk type freezer, but direct cooling system is used here and a
tube shaped freezing cylinder which causes extremely fast
freezing mixture. Metered amount of air and mix is forced into
the freezing tube and emulsified there. The frozen mixture is
forced out on the other end of the tube by pressure of a second
pump. Ammonia is circulated by means of jet action so that it
floods the freezing tube during operation of the machine.

43. CREAMRY PACKAGE FREEZER
Compressed air is passed through a filter, a pressure gauge and check valve
which are provided in the line. Ice cream mix is pumped with the help of
mix pump and enters the freezing cylinder along with air. Ice cream after
freezing is pumped out with the help of discharge pump. A filling valve is
provided between the freezing cylinder and discharge pump. The actual
control of overrun of predetermined point is accomplished by controlling
the output ice cream as compared to the input of mix. This could be done by
actually changing the speed of the ice cream pump only. However, in
practice, it has been found that a much simple method is to vary the output
of ice cream by changing the pressure on the freezing cylinder , by means of
air pressure regulator. The pipeline for ice cream should be kept as short as
possible.

45. Latest technology to flavour the ice cream

47. CHOCOBAR MAKING MACHINE
• The various sticks are positioned in an inverted
position.
• The mix with the help of especial arrangement
surrounds sticks.
• The unfrozen system is passed into hardening
cabinets and further for packaging.

48. CHOCOBAR MAKING MACHINE

52. The Gram Equipment machine is capable of producing
round and rectangular ice cream sandwiches, with
capacities of up to 8,000 products per hour. The
Sandwich ice cream equipment is of high quality and
can be designed with your specifications.
• All stainless steel construction
• Mechanically-driven dual wire extraction
system
• Unique picture-in-place system to work in
conjunction with wrapping material requiring
photocell registration.
• Automatic sanitation with the "no biscuit, no ice
cream slice" control system.
• Centralized electrical control panel

54. •It is a kind of batch freezer in which overrun
is kept low.
•The softy making machine belongs to
this class only.

55. SOFT SERVE
FREEZER

56. A kind of batch freezer in which dasher rotates slowly
as compared to normal
Batch freezers.

57. Features:
- Compact model and exquisite
look.
- New Tropicalised design
resulting in high product output
with low power consumption
- The machine is easy to use
- Insulated dispense head tap
made of excellent insulating
material

58. HARDENING
• When ice cream is drawn from freezer and put
into the container to be placed in the hardening
room, it has semi solid consistency not stiff
enough to hold its shape.
• The freezing process is continued without
agitation at the temperature of minus 18 degree
Celsius.

59. In order to get desired texture or firmness to ice cream , the product is hardened at
Specific temperature for certain fixed period of time.

60. AMUL CHEST DEEP FREEZER

61. AMUL SCOOPING CABINET

62. REFERENCES
1. Outlines of Dairy technology,38th impression 2013 SUKUMAR DE
2. Dairy Plant Management and engineering, Tufail Ahmed
3. Dairy Processing Handbook. 1995. Tetra Pak Processing Systems
AB, Sweden.
4. Kessler. 1981. Food Engineering and Dairy Technology. V.A.
Kessler Publ., Freising, Germany.
5. McCabe, W., Smith, J. and Harriott, P. 1993. Unit operations of
Chemical Engineering. Mc-Graw Hill Inc. New York.