Optimization of Particle Size Distribution of Coco Pith: Implications of Soil Suitability Classes, Varietal Variation, Processing Method and Status of Ageing

This study was conducted to investigate the impact of the genetic nature of coconut palm varieties (TT and DT), soil suitability classes (S1-S4), fiber extraction method (Wet milling and Dry milling), and ageing status (aged and non-aged) on the PD (Second particle size (0.2 mm – 1 mm), fourth particle size (1 mm – 2 mm), fine particle size (< 0.2 mm) and fiber fraction (> 2 mm)) of CP (CP) obtained from the coconut husk sampled from the Coconut Triangle in Sri Lanka. The results revealed the PD of CP varies (P<0.05) based on their genetic nature, environmental factors, and the fiber extraction process. Moreover, the effect of these factors and their interaction varied depending on the particle type. The optimal fine particle content (<0.2 mm) below the preferred threshold (less than 10%) was obtained in variety DT when cultivated in S1 and S2, as well as in S4 with aging, regardless of the milling method. Similarly, variety TT exhibited lower fine particle content when grown in S1 with aging, S4, and in S2 and S3 regardless of the aging process. Ageing enhanced dry-milled coir pith by reducing short fiber content while wet milling elevated short fiber content in wet-milled coir pith. Hence, the inclusion of aging should be guided by the targeted PD and the specific milling technique employed.