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Analysis of physicochemical and thermo-mechanical characteristics of Iranian black seed (Nigella oxypetala Boiss)

Seyed Mohammad Taghi Gharibzahedi, Seyed Mohammad Mousavi, Mohammad Jouki, Mohammad Ghahderijani
International journal of food engineering 2012 v.8 no.3 pp. -
Nigella, aluminum, angle of repose, bulk density, chemical analysis, energy, engineering, fatty acid composition, friction, mineral content, nutritive value, plywood, porosity, processing equipment, seeds, specific heat, steel, thermal conductivity, thermal diffusivity, water content
The study experimentally scrutinized nutritional and engineering properties of Iranian black seed at a moisture content of 5.1% (w.b.) in order to design processing equipment and machinery for various post-harvest operations. Analysis of chemical composition, mineral content and fatty acid profile illustrated that the seeds had high nutritional value. Bulk density, true density and porosity were 539.3 kg/m3, 1009.4 kg/m3 and 46.5%, respectively. Mean values for angle of repose and terminal velocity were 5.6 m/s and 32.5°, respectively. Static friction coefficient on plywood, mild steel, aluminum and galvanized iron sheet were 0.53, 0.36, 0.32 and 0.37, respectively. Specific heat, thermal conductivity and thermal diffusivity varied from 1642 to 2035 J/kgK, 0.17 to 0.22 W/mK and 9.3 to 10.4 × 10-8 m2/s, respectively. The force required for initiating seed rupture decreased from 57.36 to 35.1 N and 55.7 to 30.24 N, and the energy absorbed at seed rupture decreased from 51.24 to 21.31 mJ and 26.67 to 6.31 mJ, with increase in loading rate from 1 to 10mm/min, for vertical and horizontal orientations, respectively.