Seminar Nasional Sains & Teknologi V Lembaga Penelitian Universitas Lampung 19-20 November 2013 1224 PERUBAHAN KELEMBABAN RELATIF DAN KANDUNGAN UAP AIR UDARA PENGERING SELAMA PENGERINGAN CHIP SINGKONG DENGAN CABINET DRYER DENGAN PEREKAMAN DATA MENGGUNAKAN MULTI MEDIA CARD Devi Yuni Susanti 1) , Joko Nugroho Wahyu Karyadi 1) , dan Setiawan Oky Hartanto 2) 1) Jurusan Teknik Pertanian, Fakultas Teknologi Pertanian, Universitas Gadjah Mada, 2) Alumni Jurusan Teknik Pertanian, Fakultas Teknologi Pertanian, Universitas Gadjah Mada Jl. Flora No 1. Bulaksumur, Yogyakarta 55281; ABSTRACT The change on physical properties of drying air and the moisture content of cassava chip are important to be explored in order to evaluate drying process and the performance of dryer. The aim of this research was to evaluate the change on relative humidity of drying air, the amount of water vapour based on relative humidity record by multi media card and accumulation of drying process. The drying process was set in 3 variation of temperature (50, 60 and 70 °C) and 3 variation of chip’s mass (4, 8 and 12 kg). The amount of chip’s mass did not affect significantly on the rate of its temperature increasing, its evaporation rate and the accumulation of water vapour in drying air. The relative humidity of the air was decreased during drying. It showed that the accumulation of water vapour was removed largely by exhaust fan and its accumulation did not affect on the increasing of relative humidity significantly. Its accumulation can be seen as the difference of relative humidity in drying air in specific mass and zero mass of cassava chip. Keyword: drying air, drying process, relative humidity, water vapour, PENDAHULUAN Pengeringan merupakan kegiatan yang sering dilakukan dalam proses pascapanen untuk memperpanjang umur simpan komoditas pertanian. Menurut Hall (1957) dan Brooker dkk (1974), proses pengeringan adalah proses pengambilan atau penurunan kadar air sampai batas tertentu sehingga dapat memperlambat laju kerusakan bahan pertanian akibat aktivitas biologis sebelum dimanfaatkan. Pengurangan kandungan air dari dalam bahan ini diharapkan dapat mengurangi resiko kerusakan bahan akibat aktifitas enzimatis dan biologi sehingga kualitas bahan pertanian dapat dipertahankan. Pengeringan bertujuan mengurangi kandungan massa air dari dalam bahan. Pengurangan tersebut ditujukan untuk