Bulk density is defined as the ratio of the mass of the sample-particle bed in a vessel to the volume of the bed
(including the voids among primary particles),
for its measurement 20 g of orange peel were weighed in a graduated
cylinder of 100 mL and the occupied volume was registered.
Apparent density was determined using a pycnometer and calculated as reported by Barbosa-Canovas et al. (2006).