Optimal Grinding Characteristics of Black Pepper for Essential Oil Yield

Abstract

Black pepper (Piper nigrum L) was ground to different particle sizes at ambient conditions, and the ground material temperatures at the mills’outlet were recorded. The surface mean diameter (ds) and geometric mean diameter (dga) of the pepper grits were determined by sieve analysis. Energy for size reduction was computed using Bond's equation. The quantity of essential oil distilled, using Clevenger's method, was recorded at 30 minutes interval for each particle size. Effective diffusion coefficient (D) determined using Fick's second law, was constant (1.38 × 10−11 m2s−1) for higher oil concentrations and it was very less in lower oil concentrations. The essential oil yield was evaluated in terms of four major compounds using gas chromatographic analysis. The particle size (dgo) of about 0.7 mm was found to be optimal for distillation of essential oil.

Extraction of the essential oil of thyme and black pepper by superheated steam

“…This difference is due to the increase of the area for material exchanges and to the burst of cells obtained by grinding. Murphy, Meenakshi, and Srinivasa Rao (1999) concluded too that grinding of black pepper increases the yield of essential oil but not in the same rate of our results, it increases from 1% to 3% when the particle geometric mean diameter decreases from 2.1 to 0.14 mm.…”

An innovative process for the production of spices through immediate thermal treatment of the plant material

“…Water content of lyophilized pepper powder ranged from 4.0% to 5.9% (Table 2). During comminution of pepper the loss of oil was found to increase with grinding energy and reduction of particle size (Murthy, Rani, & Srinivasa Rao, 1999). However, besides grinding vacuum drying for 70 h was considered the most crucial step during spice production 1.08*10 7 5.92*10 5 1.00*10 4 6.00*10 5…”

Cryogenic grinding of black pepper

“…Average particle size was then calculated for the powder (McCabe, Smith, & Harriot, 1985;Murthy, Rani, & Srinivasa Rao, 1999).…”

“…The samples were analyzed in a gas chromatographic analyzer (GC-Shimazdu-15, Japan) as mentioned by Murthy et al (1999).…”