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1. Title of the sub-project:

Studies on Cryogenic Grinding for Retention of Flavour and Medicinal Properties of Some

Important Indian Spices

2. Sub-Project Code: NAIP/Comp4/C30028

3. Name of the Consortium leader and partners :Consortium Leader: Central Institute of Post-Harvest Engineering & Technology (CIPHET),

Ludhiana

Consortium Partners:

1. Indian Institute of Technology (IIT,K), Kharagpur

2. Indian Institute of Spices Research (IISR), Marikunnu Post, Calicut

3. National Research Center on Seed Spices (NRCSS), Ajmer, Rajasthan

Consortium PI: Dr. K. K. Singh, Principal Scientist, CIPHET, Ludhiana

(singh_ciae@yahoo.com)

Consortium Co-PI:1.Dr. T.K .Goswami

2. Dr. T. John Zachariah

3. Dr. S. N. Saxena

Consortium website: www.ciphet.in/NAIP/Cryogenic

4. Objectives:

Characterization of selected spices based on physico-chemical, mechanical, thermal

properties and quality attributes

Studies on grinding kinetics, particle size distribution, energy requirement and quality

attributes in available cryogenic and ambient grinding systems

Modelling of heat and mass transfer in cryogenic grinding of spices and subsequent

packaging environments

Development of experimental cryogenic grinding system for spices by modification of

a pin and a hammer mill.

Optimization of grinding conditions in different systems and comparative performance

evaluation for appropriateness of grinding system using different spices.

5. Duration: Abouttwo & half years ( 2008-09 to 2011-12)6. Total estimated Cost: Rs. 398.10 lakh

7. The rationale:

India produces about 4 million tones of spices annually (2006-07). The main processed

product of spices is ground powder. The aim of spice grinding is to obtain smaller particle

size with good product quality in terms of flavour and colour. Due to high fat content in

spices, in the normal grinding process, heat is generated when energy is used to fracture a

particle into a smaller size. This generated heat causes temperature rise in the grinder to the

extent of 95o

C, which is responsible for a loss of volatile oil in the tune of about 30% and also

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produces dark colour powder. Generally, a continuous operation of grinder is not possible in

normal grinding process due to melting of fat and sticking of powder on the grinding

surfaces. The normal grinding produces poor quality of powder that does not conform to the

international quality standards, as a result either fetches lower price or not accepted by the

importer countries. The temperature rise of the product can be minimized to some extent by

circulating cold air or water around the grinder. But this technique is not sufficient tosignificantly reduce temperature rise of the product. The loss of volatile can be significantly

reduced by cryogenic grinding technique using liquid nitrogen or liquid carbon dioxide that

provides the refrigeration needed to pre-cool the spices and maintain the desired low

temperature by absorbing the heat generated during the grinding operation. The extremely

low temperature in the grinder solidifies oils so that the spices become brittle, they crumble

easily permitting grinding to a finer and more consistent size. The high quality ground

product would have domestic as well as international market. Limited research information is

available on cryogenic grinding of spices. The sub-project proposes to characterize

engineering and chemical properties of spices, modelling of heat and mass transfer in

cryogenic grinding of spices, development of experimental cryogenic grinding systems and

optimization of grinding conditions in different systems and their comparative performance

evaluation.

Major Innovations to be attempted

Modeling of heat and mass transfer in cryogenic grinding of spices with minimal damage to

flavour and chemical characteristics.

Design of cryogenic pre-cooling and liquid nitrogen injection system for a grinder

Development of experimental cryogenic pin and hammer mills so that available grinders

can be used with minimal modifications.

8. Outputs:

Data base on physical, mechanical, thermal and bio-chemical properties of selected spices

Mathematical model for heat and mass transfer and energy use in cryogenic grinding of

spices

Experimental cryogenic grinding systems

Information on comparative evaluation of different grinding systems regarding retention of

flavour and chemical characteristics and energy use.

Information on optimum packaging and storage conditions

9. Expected outcome and impact:

The market value of processed important spices of India in the internal and export markets islikely to substantially increase based on the development/adaptation of cryogenic system in

grinders.

The models developed may be useful in development of other cryogenic processing systems.