Physicochemical characterization and mass modelling of Roselle (Hibiscus sabdariffa L.) calyx and seeds

Abstract

Roselle (Hibiscus sabdariffa L.) calyx and seeds are underutilized, whose utilisation can be widened with the design and development of proper post-harvest systems. For this purpose, a detailed study on its engineering properties is necessary. Hence, the main goals of this study were to investigate the physical, biochemical, thermal, and textural properties of Roselle and to select the most precise models for calculating the mass from its physical properties. Roselle calyx has an average weight of 3.106 g, actual density of 1.04 g/cm3 and bulk density of 0.89 g/cm3. Similarly, Roselle seeds has an average weight of 1.427 g, actual density of 1.37 g/cm3 and bulk density of 0.65 g/cm3. Moreover both the calyx and seeds were found to be rich in protein, phenols and minerals. Finally, the FTIR analysis identified the presence of esters, ethers and carboxylic acids in Calyx and alkyne, alkane, hydroxyl and amide groups in the seeds. In addition, the mass was conducted using four different empirical models, and the power model was found to be the most suitable. The present research will considerably broaden our understanding and be instrumental in creating post-harvest machinery that will increase its value and enable its commercial production.