ISOTERMAL SORPSI AIR DAN KARAKTERISASI PENGERINGAN CABAI PUYANG (Piper retrofractum Vahl)

Abstract

Long pepper (Piper retrofractum Vahl) is one of Indonesian potential medicinal plants to explore and developed, and drying is one of critical steps for its processing. In this report, the adsorption and desorption isotherms of Indonesian long pepper was performed in the range of water activity (a_w) from 0.06 to 0.84 at 25, 40 and 50°C, and the applicability of GAB model in data prediction was evaluated. Additional information regarding long pepper drying related characteristic, i.e. its drying rate at 50°C were also investigated. The results indicated that Indonesian long pepper presented Type II and the hysteresis effect was observed. GAB model precisely represented the sorption isotherms behavior of long pepper with based on coefficient of determination (R²), mean relative percent error (P) and root mean square error (RMSE). The results also indicated that at drying temperature 50°C, the moisture equilibrium reached after 1260 min for 8.0% (db). For longer and better stability during storage, moisture content <10% (db) was suggested.

Keywords: Long pepper, Sorption isotherms; Drying; GAB model.