this presentation speaks about the extrusion technology and incorporation of fruits and vegetable for enhancing the nutritional of the extruded food product.

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4. 4Mike Adams

5. UNIVERSITY OF HORTICULTURAL SCIENCES
BAGALKOT
COLLEGE OF HORTICULTURE, BAGALKOT
Seminar – I
“Extrusion Technology: A potential technique for
vegetables and fruits based snack food product”
Ms: Ayeeshya Kolhar
UHS17PGD223
Ph.D (II yr)
Dept of Post Harvest Technology 5

6. Introduction
Production technique and it’s components
Food extruders- Types & application
Physico- chemical changes
Factors affecting extrusion process
Advantages & Limitations
Case studies
Conclusion
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7. The word “extrudate” originates from the Latin word “ex”
(out) and “trudere” (to thrust).
Extrusion is defined as “A process in which material is pushed
through an orifice or a die of given shape, the pushing force is
applied using a piston or a screw.”
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Karwe, 1992

8. Extrusion is a process which combines several unit operations
including mixing, kneading, cooking, shearing, shaping, forming,
conveying, separation, venting, flavor generation, plastification
and expansion of the food structure.
Fellows, 2000
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Table 1: History
INVESTIGATOR YEAR FINDINGS
MC.Anelly 1964
First to describe a process for the
production of spongy elastic
particles from soy flour.
Atkinson 1970
Disclosure of a continuous cooking
extrusion process
EL-Dash 1981
First to process breakfast cereal
products
Noguchi. 1998
Extrusion cooking of high moisture
protein foods
Fast 2000
RTE cereals
Saalia 2011
Degradation of afflatoxins by
extrusion
Ryan 2011 Oat based breakfast cereal snack
Rao and Thejaswini, 2015

10. PRODUCTION TECHNIQUE
As a result, it fills the barrel and the spaces between the screw
flights and becomes compressed
Further down the barrel, smaller flights restrict the volume and
increase the resistance to movement of the food
Raw materials are fed into the extruder barrel and the screw(s)
then convey the food along it.
Bordoloi and Ganguly, 2014
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11. It is forced through one or more restricted openings (dies) at the
discharge end of the barrel as the food emerges under pressure
from the die, it expands to the final shape and cools rapidly as
moisture is flashed off as steam
As it moves further along the barrel, the screw kneads the material
into a semi-solid, plasticized mass.
Fig. 1: Expansion of the product Bordoloi and Ganguly, 2014
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12. COMPONENTS OF EXTRUSION SYSTEM
Feeding system
Pre-conditioning system
Screw or worm
Barrel
Die and the cutting mechanism
Rao and Thejaswini, 2015 12
Fig.2 COMPONENTS OF EXTRUSION SYSTEM

13. GENERAL CONDITIONS
Temperature : 52-199 ° C
Pressure :1500- 70,000 KPa
Time :15-19 sec
Screw speed :150-600 rpm
Rao and Thejaswini, 2015
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14. FOOD EXTRUDER
Fig.3: Food extruder 14Bordoloi and Ganguly, 2014

15. CLASSIFICATION OF EXTRUDERS
BASED ON
OPERATION
HOT
COLD
BASED ON
CONSTRUCTION
SINGLE
SCREW
TWIN
SCREW
15Bordoloi and Ganguly, 2014

16. SINGLE-SCREW EXTRUDERS
The most common extruders applied in the
food industry.
The barrels of single-screw extruders usually
have helical or axial grooves on inner surfaces.
This helps to convey and mix the material more
effectively.
Fig. 3: Single-screw extruder
Caldwell , 200016

17. The first major commercial application of the in the food
processing industry was conversion of semolina flour into
pasta using solid screws.
Application
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Huber, 2000

18. Twin-screw extruder
The term ‘twin-screw’ applies to extruder with two screws of equal
length placed inside the same barrel.
More complicated than single screw extruders, but at the same time,
provide more flexibility and better control.
Maurya and Said, 2014
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19. Application
Processing plastics
Food companies (sticky caramels and candies)
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Maurya and Said, 2014

20. RAW MATERIALS USED
The most used raw materials- starch and protein based
materials, and are used in solid form (Steel et al., 2012).
Most products such as breakfast cereals, snacks and biscuits–
starch (wheat, corn, rice, potato, cassava and pea flour).
Protein- meat-like characteristics (soybean).
Dehgonshoar et al., 2010
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21. Physico-chemical changes during extrusion
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22. The starch polymer becomes glassy as moisture is
removed, forming a hard brittle texture
Dispersed and degraded to form a continuous fluid
melt
Heat & the action of shear destroy the organized
molecular structure, also resulting in molecular
hydrolysis of the material
At relatively high temperatures, the starch granules
melt and become compressed to a flattened formChangesinstarch
Rao and Thejaswini, 2015
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23. Enzymes lose their activity after being submitted to high
temperatures and shear
High molecular weight proteins can dissociate into smaller
subunits
During extrusion, disulfide bonds are broken and may re-
form
Proteins are more reactive and undergo many changes
during the extrusion process, most important being
denaturation
Changesinprotien
Rao and Thejaswini, 2015
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24. Changes in lipids
Lipids acting as lubricants.
They reduce the friction between particles in the mix
and also between the screw and barrel surfaces.
Rao and Thejaswini, 2015
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25. Changes in Fibres
Rao and Thejaswini, 2015
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26. Anti-nutrients
Extrusion cooking destroys many natural toxins and anti-
nutrients, there by improving safety of the food product.
Compounds such as allergens and mycotoxins susceptible to
extrusion in combination chemical treatments.
Rao and Thejaswini, 2015
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27. Influence of extrusion cooking on various parameters
Nutritional quality
Microbiological quality
Product quality
Rao and Thejaswini, 2015
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28. Fruit or vegetable blended extruded products
Cereal
Fruits, vegetables, by-products etc.
Snacks with different appearance and flavour
with improved nutrition.
Bordoloi and Ganguly, 2014
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30. Objective: To incorporate cauliflower by-products as a source of dietary fibre into ready to-
eat snacks and evaluating it’s effect on nutrition and sensory attributes of ready to-eat
expanded snacks
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Table 2: Formulations for extrudate development
Ingredients (% w/w)
Wheat flour 16.4–36.4
Cauliflower 0–20
Corn starch 20
Oat flour 10
Egg whites 10
Milk powder 10
Onion powder 03
Tomato powder 05
Carrot powder 05
Dill 0.1
Mint 0.1
Salt 0.4
Stojceska et al., 2008

32. Process conditions Process conditions
Solid feed rate : 20-25 kg/ h
Water feed : 9-11%
Screw speed : 250-350 rpm
Temperature : 80°C at the feed entry
120°C at the die exit
Stojceska et al., 2008
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Table 3: Nutritional characterization of raw materials (A) and
extruded products (B)
Stojceska et al., 2008

34. Fig. 5: Images of extrudates containing different levels of cauliflower.
Stojceska et al., 2008
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35. Fig. 6: Influence of cauliflower level on taste panel
acceptability score
Stojceska et al., 2008
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Inference
•Incorporation of cauliflower by-products into ready-to-eat snacks
and their effect on nutritional and textural characteristics were
positively affected.
•The taste panel acceptability score showed that cauliflower by-
products could be added up to 10%.
Stojceska et al., 2008

37. Objective: To characterize and evaluate the performance of pineapple pomace as
an ingredient in extruded products.
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38. Table 4:Chemical composition of freeze-dried pineapple pomace
Component Percentage (% )
Moisture 3.77 ± 0.52
Protein 4.71 ± 0.28
Fat 0.61 ± 0.14
Total Dietery fibre 45.22 ± 3.62
Insoluble Dietery fibre 44.44 ± 3.60
Soluble Dietery fibre 0.78 ± 0.10
Carbohydrates 43.46
Selani et al., 2014
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39. Table 5: Physicochemical composition of freeze-dried
pineapple pomace
Physicochemical parameters Pineapple pomace
pH 3.86 ± 0.07
Titratable acidity (g /100 g) 2.01 ± 0.23
Water activity (aw) 0.14 ± 0.06
Colour: L* 75.63 ± 3.07
a* -0.10 ± 1.79
b* 26.91 ± 2.35
Selani et al., 2014
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40. Experimental setup
Pineapple pomace : 0%, 10.5%, 21%
Moisture : 14%, 15%, 16%
Temperature : 140° C & 160° C
Single screw extruder with screw speed – 220 rpm
Control : 14% moisture + no fibre
Selani et al., 2014
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Averages followed by different letters are significantly different (p < 0.05) by Tukey’s HSD test. Data with logarithmic
transformation (base 10). The comparison among the means was performed with transformed data and the results presented
in the original scale.
Selani et al., 2014
Table 6: Effects of the pineapple pomace incorporation on the physical
characteristics of the extrudates

42. Fig. 7: Appearance of the extruded products
Selani et al., 2014
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43. Factors influencing the quality of the product
I. Rheological properties of the food
Type of feed materials
Moisture content
Physical state of the materials
Chemical composition
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44. II. Operating characteristics
Temperature
Pressure
Diameter of the die apertures
Shear rate.
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45. Objective: To evaluate physical characteristic and microstructure of extruded
product.
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46. Experiment
Control : 100 % corn grits
Treatments : Corn grits with pumpkin flour (5, 10,15 and 20 per cent)
Screw speed - 250 and 350 rpm
Barrel temperature – 1600C
Evaluation - physical characteristics of snacks
Nor et al., 2013
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47. Fig. 9: Effect of screw speed and the proportion of pumpkin flour
on the expansion ratio
Nor et al., 2013
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48. Nor et al., 2013
Fig.10: Effect of varying pumpkin flour percentage and screw speed on the
hardness of extruded product.
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49. Nor et al., 2013
Fig. 11: Effect of varying pumpkin flour percentage and screw speed
on the bulk density of extruded product.
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50. Table 7: X-ray tomography cross sectional of 2-D image (radial): changes of
bubble size through out the extruded sample at screw speed 250
rpm (scale 1:2)
Nor et al., 2013
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51. Objective: To develop and evaluate extruded snacks with optimum level of
garlic powder.
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52. Experiment
Materials used
Rice flour : 50-70%
Defatted soy flour : 30%
Garlic bulbs & salt
Treatments
T1- RF 70%
T2- RF 65% + G 5%
T3- RF 60% + G 10%
T4 - RF 55% + G15%
T5- RF 50% + G 20%
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53. Sensory
parameters
Treatment ( means)
T1 T2 T3 T4 T5
RF 70% RF 65% + G 5% RF 60% + G 10% RF 55% + G15% RF 50% + G 20%
Flavour 23.53 23.80 21.80 18.26 15.26
Colour 13.20 12.73 11.00 10.46 9.86
Expansion 13.40 12.60 10.20 10.13 8.26
Texture 13.20 12.46 11.80 9.66 9.13
Odour 8.20 8.00 7.40 7.06 5.86
Overall
acceptability
12.66 13.00 11.60 8.93 8.26
Table 8: Effect of substitution of rice flour with garlic powder
on sensory analysis
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The garlic can be incorporated in the form of dehydrated
powder in rice and defatted soy based ready-to-eat extruded
snacks up to 10 % level with acceptable sensory qualities.
Inference

55. Objective: To asses the formulation, development and evaluation of
physico-chemical and sensory properties of extruded snacks with different
flour blends.
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56. Control : Corn + BG (80: 20)
Treatments : Corn flour + Black gram flour + Tuber
flour (60: 20:20)
Preconditioning
Spicing and drying
Packaging and storage
Sensory evaluation and physico chemical analysis
Reddy et al., 2014
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57. Fig. 10: RTE extruded formulations developed by incorporation of
different roots and tuber flour blends
1. Corn flour + Black gram flour
2. Corn flour + Black gram flour + Potato
3. Corn flour + Black gram flour + Taro
4. Corn flour + Black gram flour + Yam
5. Corn flour + Black gram flour + Sweet potato
6. Corn flour + Black gram flour + Beet root
Reddy et al., 2014
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58. Table 10: Mean physical parameters of the developed extruded
products
Reddy et al., 2014
Values are expressed as mean ± standard deviation of ten determinations .Mean values with similar
superscripts within a column do not differ significantly (P>0.05). C -corn, BG - black gram
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59. Table 11: Proximate analysis of extruded snacks (per 100 g)
Reddy et al., 2014
Values are expressed as mean ± standard deviation of ten determinations .Mean values with similar
superscripts within a column do not differ significantly (P>0.05) . C - corn, BG - black gram
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60. Fig. 13: Mean sensory scores of the extruded products
Reddy et al., 2014
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61. Fig. 14: SEM images of control and most acceptable extruded snack
(potato incorporated extruded products). Reddy et al., 2014
A. External SEM image of control extrudate B. External SEM image of potato incorporated
extruded products
C. Internal SEM image of control extrudate
D.Internal SEM image of potato incorporated
extrudate
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62. Advantages
Versatility
Cost
Nutritional improvement
Productivity
Product quality
Environmentally-friendly
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Tripathi and Mangaraj, 2013

63. Disadvantages
High capital cost
Non-availability of spare parts
Repairs and maintenance
Power failure
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Tripathi and Mangaraj, 2013

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Companies involved

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CONCLUSION…

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Proper handling and processing of the waste generated by
fruits and vegetable processing industry into extrudable form.
Commercialization of the fruits and vegetable incorporated
extruded snack products.
Creating awareness among the consumer about the fruits
and vegetable incorporated extruded snack products using
extension methodologies.
Future line of the work………….

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Thank you…

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