Influence of pre-processing and coir extraction methods on the physicochemical properties and microbial contamination of coir pith

Abstract

Particle size, pH, electrical conductivity, water retention capacity and drying characteristic of coir pith' determine the quality of the final product. These parameters may influence by the time duration for retting, method of crushing and the mode of mechanical extraction. Two types of fiber extraction methods namely Ceylon Drum method and D1 method were examined. Ceylon Drum gave higher percentage of fine particles while D1 method gave higher percentage of medium size particles. Higher fraction of fine particles could be obtained by increasing the retting time. Retting time was significantly lowered by crushing the husk. However, it resulted in lower percentage of fine particles and significantly high percentage of medium particles (more than 75%) suggesting a possible mechanism for obtaining required particle sizes through a combination of crushing and retting. Retting increased the initial moisture content of coir pith but the drying characteristic was not significantly altered as compared to water spraying. Water retention capacity ^(5.75 ± 0.67), volume expansion (5.70± 0.46), pH (5.83 ± 0.19) and electrical conductivity (540 ± 152 W ps/cm) were similar among the sundried coir pith obtained from different pre-processing methods. Initial microbial count was significantly high for retted coir pith but the retained microbial strains