Tujuan penelitian ini adalah untuk mempelajari proses pengeringan irisan temuputih (Curcuma zedoaria (Berg.) Rosc.) serta untuk menentukan kondisi proses pengeringan yang optimal dalam menghasilkan simplisia temuputih yang memenuhi standar. Kriteria kondisi tersebut adalah yang dapat memenuhi kadar air standar 10%, memenuhi kriteria mutu yang ada, waktu pengeringan yang cepat, memiliki kadar kurkumin yang tinggi dan tampilan visual yang optimal. Hasil studi menunjukkan bahwa suhu dan kelembaban udara pengering berpengaruh terhadap kadar air akhir yang dapat dicapai, dimana suhu 40 °C tidak dapat mencapai kadar air 10%. Laju udara pengeringan berpengaruh terhadap kadar air akhir dan kadar kurkumin. Terdapat kecenderungan semakin rendah laju udara pengeringan maka semakin tinggi kadar kurkumin simplisia temuputih. Kondisi suhu pengeringan berpengaruh terhadap tampilan warna temuputih kering. Kondisi proses pengeringan yang direkomendasikan untuk mendapatkan simplisia temuputih standar adalah pada suhu 50 °C dan RH 20% dengan laju udara pengeringan 0,2-0,3 m/detik.

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The objectives of this study were to determine a suitable thin layer drying model to describe the drying kinetics of Guazuma ulmifolia leaves and determine the mass transfer parameters of Guazuma ulmifolia leaves. The drying of Guazuma ulmifolia leaves was conducted in a laboratory scale dryer with various temperature (40oC, 50oC, and 60oC) and relative humidity (30%, 40%, 50% and 60%). Five drying models, namely, Newton, Henderson and Pabis, Page, Midilli-Kucuk, and Verma et al. were fitted to the drying data. The drying curve of guazuma leaves did not show a constant drying period during the drying period. The models suitability were compared base on coefficient of determination (R2), root square mean errors (RSME), and reduced mean square of deviation (X2). It was found that, among the models evaluated, the Midilli and Kucuk model is the best to describe the drying kinetics of Guazuma ulmifolia leaves. The effective moisture diffusivity was found to be in the range of 10-13 – 10-12 m2/s and the convective mass transfer coefficient was in the range of 10-9 – 10-10 m/s. The activation energy value was found to be 89.21 kJ/mol.

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Sun drying is the traditional method for drying and still preferred in Asia because cheap compared to mechanical drying. Since it uses the sun as heat source it is friendly to the environment, many farmers, grain collectors, traders and millersoften dry their paddy on pavements that specifically constructed for drying. Sundrying pavements have the advantages of high capacity and thus economics of scale, but the weakness is very dependent on the weather. The amount of paddy that can be dried with a drying depends on the number of sunny days, so it is important to know the probabilities of rainy day based on the historical climate data in a region. From these, simulations can be done to calculate how many dryer machines should be provided to overcome the lack of drying capacity. This methodis known as Monte Carlo. This paper presents a study to determine the amount mechanical dryer needed based on the failure probability of sun drying pavements using monte carlo simulation methods in the District of Ciomas, Bogor.The study results based on 10 years daily rainfall data the probability of rainy days in March (0.62) was greater than in September (0,37), so that the total capacity of dryer machine to be prepared is 110 tons/ day. That was equal to 11 units dryerswith 10 tons / unit in capacity.