ANALISIS PERPINDAHAN PANAS DAN MASSA PADA PENGERINGAN BUAH MENGGUNAKAN PENGERING VAKUM YANG DI KOMBINASI DENGAN PROSES OSMOTIK

ACHMAD KOKO WIJANARKO, Dr. Joko Nugroho WK, STP, M.Eng.

2013 | Skripsi | TEKNIK PERTANIAN

Tujuan penelitian ini adalah menentukan kinetika pengeringan buah dengan pemberian proses osmosis dan berbagai perlakuan awal.Pengering vakumdengan pemanas listrik digunakan dalam penelitian.Potongan buah nanasdan salakdigunakan sebagai bahan penelitian. Perendaman dalam larutan gula diberikan pada setiap perlakuan awal. Perendaman dalam larutan asam sitrat, sodium metabisulfit, kalsium klorida, dan perlakuan blansir, larutan asam sitrat, sodium metabisulfit, dan perlakuan blansir, larutan asam sitrat, sodium metabisulfit, dan kalsium klorida, larutan asam sitrat dan sodium metabisulfit, sertalarutan kalsium klorida, asam sitrat, dan perlakuan blansir masingmasingdigunakan untuk perlakuan P1, P2, P3, P4, dan P5. Hasil penelitian menunjukan bahwa pengeringan vakum dengan perlakuan osmosis mampu menurunkan kadar air buah salak dannanasmasing-masing dari sebesar 81,05% dan 87,08% menjadi 16,75% dan 26,41%. Waktu yang dibutuhkan untuk mengeringkan buah dengan pengering vakum adalah 24 jambaik untuk buah salak maupun nanas. Laju pengeringan dalam analisis basis kering pada periode konstan untuk buah salak dan nanasmasing-masing berkisar antara 15,63%/jam – 26,05%/jam dan 38,78%/jam – 55,67%/jam, sedangkan pada periode menurun masing-masing berkisar antara 0,30/jam – 0,50/jam dan 0,29/jam – 0,42/jam. Koefisien perpindahan panas konveksi buah salak dan nanasmasing-masing berkisar pada 0,10 W/m2.oC –0,25 W/m2.oC dan 0,07 W/m2.oC –0,18 W/m2.oC. Penggunaan bahan aditif, seperti asam sitrat, kalsium klorida, dan sodium metabisulfit serta pemberian perlakuan blanching tidak memberikan pengaruh signifikan terhadap proses pengeringan yang ditunjukkan dengan tidak berbedanya nilai laju pengeringan dari masing-masing perlakuan yang berbeda. Pengeringan buah dengan pengering vakum memberikan produk akhir yang baik apabila buah direndam dahulu dalam larutan sodium metabisulfit dan asam sitrat, larutan kalsium, diberi perlakuan blansir, serta direndam dalam larutan gulasebelum dilakukan proses pengeringan.

fruit with osmotic process and various pretreatments.Thevaccuum dryer with electric heater was used in this research.The sliced of pineappleand snake fruit were used as samples. Sugar solution dipping was used for all variations. Citric acid, sodium metabisulphite, and calcium chloride dipping combined with blanching, citric acid and sodium metabisulphite combined with blanching, citric acid, sodium metabisulphite, and calcium chloride dipping, citric acid and sodium metabisulphite dipping, and citric acid and calcium chloride combined with blanching were noted as P1, P2, P3, P4, and P5 variation respectively. The result showed that the vaccuum drying combined with osmotic process pretreatment had effect on reducing themoisture content of snake fruit and pineapple from 81,05% and 87,08% respectively to 16,75% and 26,41% respectively. The time needed for drying fruit process with vaccuum dryer was 24 hour for both snake fruit and pineapple. The drying rates for dry basis analysis at constant period of snake fruit and pineapplewere 15,63%/hour – 26,05%/hourand 38,78%/hour – 55,67%/hour respectively, while the drying rates at falling period were 0,30/hour – 0,50/hourand 0,29/hour – 0,42/hourrespectively. The coefficients of convective heat transfer of snake fruit and pineapplewere 0,10 W/m2.oC – 0,25 W/m2.oC and 0,07 W/m2.oC – 0,18 W/m2.oC respectively. The use of additive materials such as citric acid, calcium chloride, and sodium metabisulphite, and also the blanching treatment had no effect on drying process of snake fruit and pineapple by vaccuum dryer which was showed by the drying rate of every variation that had no significant differences. The fruit drying process using vaccuum dryer gave the best result if the fruits were dipped on sodium metabisulphite, citric acid, andcalcium chloride solution, given the blanching treatment, and dipped on sucrose solution (sugar solution) before they were put on the dryer.

Kata Kunci : Buah, pengeringan, pengering vakum, osmotik, bahan aditif