The document discusses cryogenic grinding technology for preserving the aroma and flavor of spices. Cryogenic grinding involves cooling spices with liquid nitrogen before grinding. It has several advantages over conventional grinding such as producing spices with brighter color, higher volatile oil retention, less clogging, and better storage stability. Experimental studies showed cryogenically ground spices had lower energy usage, finer particles, and higher volatile oil levels compared to conventionally ground spices. The document concludes cryogenic grinding is a promising technology that can produce higher quality spice powders for the food and pharmaceutical industries.

1. ICAR-Central Institute of Post Harvest Engineering & Technology
Preservation of Aroma and Flavor of Spices/Herbs
through Cryogenic Grinding Technology
Dr. Pankaj Kumar, Scientist
Division of Food Grains and Oil Seeds
ICAR-CIPHET, Ludhiana

2. ICAR-Central Institute of Post Harvest Engineering & Technology
 Introduction
 Problems in Conventional Grinding
 Working of Cryogenic Grinder
Advantages of Cryogenic Grinding
 Experimental Studies
 Conclusion
CONTENT

3. ICAR-Central Institute of Post Harvest Engineering & Technology
 India is the home of spices
 Spices are used to enhance the
taste and flavour of food
 India is the largest producer and
exporter of spices
 The total production of India was
8.6 MT in 2016-2017
 India exported 1.02 MT of spices
in 2017-2018
 (Spice Board of India, 2018)
Spices…

4. ICAR-Central Institute of Post Harvest Engineering & Technology
Grinding…
 Age-old technique
 Size reduction operation
 Reduces particle size...
 Increases surface area and
 availability of constituents …
 Achieved by Hammer Mill…

5. ICAR-Central Institute of Post Harvest Engineering & Technology
 Only conventionally ground spices powder are
available in Indian market
 Cryogenic grinding plant for spices is not
available in India
 That’s why, our farmers do not get appropriate
prices for their spices
contd…

6. ICAR-Central Institute of Post Harvest Engineering & Technology
Grinding Unit
99 % convert in to heat
1% used for Size reduction
Input energy
Effect of Heat
Loss of Flavour
& Aroma
Dark colour
High energy
Consumption
Batch Process
The losses of volatile oil 37% for nutmeg, 17% for cinnamon
Temperature raises
up to 93 °C
Energy conversion in conventional Grinding
Meghwal and Goswami, 2010

7. ICAR-Central Institute of Post Harvest Engineering & Technology
Problems IN CONVENTIONAL GRINDING PROCESS
 High heat generation
 Dark colour
 Clogging and Gumming of the mill
 Oxidation
 Loss of volatile oil

8. ICAR-Central Institute of Post Harvest Engineering & Technology
Now…elimination of all these
problems are required…
But…
HOW..???

9. ICAR-Central Institute of Post Harvest Engineering & Technology
Here comes the necessity of
CRYOGENIC
GRINDING
…also known as Freeze Grinding

10. ICAR-Central Institute of Post Harvest Engineering & Technology
CRYOGENICS…
 “Cryogenics” originated from the Greek word
 Means creation or production by means of cold
 Liquid nitrogen is the most commonly used element
 It is legally purchasable around the world
 Cryogenics is the study of very low temperatures

11. ICAR-Central Institute of Post Harvest Engineering & Technology
 Involves cooling a material below its embrittlement
temperature with cryogenic fluid before grinding
Typically Liquid Nitrogen is used as a cryogen.
CRYOGENIC Grinding

12. ICAR-Central Institute of Post Harvest Engineering & Technology
WORKING

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Cryogenic Grinder
• It has two units
 Pre- cooling unit
 Grinding unit

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Ambient Cryogenic

15. ICAR-Central Institute of Post Harvest Engineering & Technology
Indigenous
Cryogenic Grinder
at CIPHET,
Ludhiana
Design by ICAR-
CIPHET

16. ICAR-Central Institute of Post Harvest Engineering & Technology
ADVANTAGES OF CRYOGRINDING
 Increased throughput & power saving
 Finer particle size
 More uniform particle distribution
 Lower grinding cost
 No heat generation
 Provides an inert atmosphere
 Reduced grinding force
 Provide clean and pollution free environment
 Prevent oxidation
 Possibility of fine grinding of difficult spices

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EXPERIMENTAL
STUDIES

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 Colour
 Energy Consumption
 Particle Size
 Volatile oil
 Clogging of Sieve
 Storage
results of cryogenic grinding
is different from conventional grinding of spices in
respect of…

19. ICAR-Central Institute of Post Harvest Engineering & Technology
Colour Quality of Cryogenic and Ambient ground Turmeric
Moisture
Content (%
Wb)
Ground Samples L* Chroma
(a2 + b2)1/2
4
AGr 51.7 76.0
CGr 54.5 39.1
6
AGr 58.5 89.6
CGr 56.1 45.9
8
AGr 53.2 86.8
CGr 58.0 46.7
10
AGr 51.9 87.9
CGr 58.2 47.8
Baranwal et. al., Int. Agrophys., 2014

20. ICAR-Central Institute of Post Harvest Engineering & Technology
Effect of Grinding Conditions on Grinding Parameters of Spices
Spices Grinding
Condition
Specific Energy
Consumption,
kWh/tonne
Specific Surface of
Mixture, mm2/g
Coriander Ambient 60.00 10251
Cryogenic 52.22 18081
Fenugreek Ambient 35.36 17857
Cryogenic 14.43 22503
Black Pepper Ambient 202.17 23544
Cryogenic 73.37 28971
Baranwal et. al., International
J. Seed Spices, 2014

21. ICAR-Central Institute of Post Harvest Engineering & Technology
Lue. et. al.,
Food chemistry,
2013
Effect of Grinding conditions on Storage Stability at 40C
Black Pepper
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0 6
Storage (Months)
Voleitile
compound
(α-Thujene,
%)
Conventional
Cryogenic

22. ICAR-Central Institute of Post Harvest Engineering & Technology
Deposition of Cumin Powder over Sieve Surface at Different Grinding Temperatures
Singh et. al., Journal of Food Engineering, 1999

23. ICAR-Central Institute of Post Harvest Engineering & Technology
(a) Ambient ground powder of Curry leaves (b) Cryogenically ground powder of Curry leaves

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25. ICAR-Central Institute of Post Harvest Engineering & Technology
 Cryogenic Grinding significantly retains quality attributes of spices
 It is superior than conventional grinding
 It has great potential to produce pharma grade spice powder
 Cryogenic grinding thus seems to be a promising technology for food and
pharmaceutical industries as well
 Thus it emerges that cryogenic grinding can further be explored for
developing high quality products

26. ICAR-Central Institute of Post Harvest Engineering & Technology