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Solid Rheological Characteristics of Black Pepper (Piper nigrum L.) During Cryogenic Grinding

Sridhar, B. S. and Manohar, B. (2004) Solid Rheological Characteristics of Black Pepper (Piper nigrum L.) During Cryogenic Grinding. Journal of Food Science and Technology (India), 41 (6). pp. 630-636.

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<p align="justify">The efficiency and output of cryogenic grinding depends upon controlled feeding done by the cryo-feeder. The present study involves the determination of volumetric efficiency of cryo-feeder based on Haaker's theory through an analytical solution to the integral equation and an equivalent angle approach. Experimental studies are reported using black pepper (Piper nigrum L.) as a model material. The range of parameters studied were: five pitches of dimensions 25, 40,50,70 and 80 mm, coefficient of friction of 0.3, radial clearances of 5, 10 and 20 mm, spraying of liquid nitrogen with 5, 10 and 20 min intervals and levels of material in the hopper 75, 150 and 300 mm. The study showed that the radial clearance at the choke section has a strong influence on the output of the feeder which is determined by the last pitch upstream of the choke section and the inside diameter of the trough at the choke section. Volumetric efficiency of black pepper during cryo-feeding ranged from 0.78 to 0.93 and was in close agreement with the theoretically determined values. Spraying of liquid nitrogen did not affect the output and volumetric efficiency of the feeder. At the point where the specific volume begins to drop and the volumetric efficiency is nearly equal to 0.5, the corresponding pitch to diameter ratio can be considered to be the upper boundary condition for conveying. The values of mean equivalent particle diameter (dm), bulk density (Pb), internal friction angle (Φw) and wall friction angle δ) for black pepper were found to be 3.4 mm, 570 kg/m3, 44.5ºand 17º, respectively.</p>

Item Type: Article
Uncontrolled Keywords: Black pepper Piper nigrum L Cryogenics, Grinding, Rheological characteristics, Solids
Subjects: 600 Technology > 08 Food technology > 30 Spices/Condiments
600 Technology > 08 Food technology > 14 Physical properties > 03 Rheology
600 Technology > 08 Food technology > 05 Processing and Engineering
Divisions: Food Engineering
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 11 Aug 2005
Last Modified: 11 Oct 2018 08:19
URI: http://ir.cftri.res.in/id/eprint/139

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