Pengaruh Ketebalan Bahan Terhadap Kinetika Pengeringan Kentang (Solanum tuberosum L.) Menggunakan Pengering Surya Metode Tidak Langsung (Indirect Solar Dryer) dan Penjemuran Langsung (Open Sun Drying)

Abstract

The purpose of this research are to find out the relation between drying rate toward moisture content and time, the relation between moisture ratio towards time with a material thickness variations, determine the kinetics model of potatoes drying, and determine the diffusivity rate of drying potatoes. The materials used were slices of potato with thickness 1 cm, 1,5 cm and 2 cm. Drying with solar energy during the day was done from 09.00 until 16.00 with Indirect Solar Dryer. Drying was stopped when reached the constant weight. As a comparison conventional drying (Open Sun Drying) was done too. Best drying results obtained samples with material thickness 1 cm using Indirect Solar Dryer. Drying rate average for this thickness was 0,018 (kg H2O/hour) / kg d.m. with final moisture content 5,02% and 21 hours drying time. The most suitable kinetic model for drying potatoes with these material thickness variation was Page with MR = exp (-0,049 t1,336) for thickness 1 cm, MR = exp (-0,066 t1,222) for thickness 1,5 cm, and MR = exp (-0,049 t1,221) for thickness 2 cm. Effective diffusivity of drying potatoes with Indirect Solar Dryer (ISD) was in the range of 1,14 x 10-9 – 5,07 x 10-10 (m2 / sec), while with Open Sun Drying (OSD) was in the range 1,22 x 10-9 – 3,04 x 10-10 (m2 / sec). Results of drying potatoes with Indirect Solar Dryer (ISD) had a better quality compared to the Open Sun Drying (OSD).