Model Perpindahan Panas dan Massa Pengeringan Stik Porang (Amorphophallus mulleri Blume) Menggunakan Cabinet Dryer dengan Perlakuan Suhu serta Karakterisasi Kualitas Produk

Karina Nur Ramadani, Dr. Sri Rahayoe, S.T.P., M.P.; Dr. Joko Nugroho Wahyu K, S.T.P., M.Eng.

2025 | Skripsi | TEKNIK PERTANIAN

Porang segar biasanya diolah menjadi chip porang kering sebelum dilakukan pengolahan lanjutan. Kontak dengan udara panas yang kurang maksimal akibat luas penampang yang kecil pada chip porang menjadi salah satu kendala dalam proses pengeringan. Stik porang menjadi salah satu solusi untuk memaksimalkan kontak bahan dengan udara panas sehingga diharapkan dapat lebih optimal dan menghasilkan produk dengan kualitas yang baik. Penelitian ini bertujuan untuk menentukan nilai koefisien perpindahan panas konveksi (h) dan konstanta laju pengeringan (kp) berdasarkan perpindahan panas dan massa pada proses pengeringan stik porang dengan menggunakan cabinet dryer dengan perlakuan suhu bertingkat dan konstan serta karakterisasi kualitas produk.

Ada empat perlakuan suhu pengeringan yang diterapkan: dua diantaranya menggunakan suhu tetap, yaitu 50°C selama 6 jam dan 60°C selama 4,5 jam; sementara dua perlakuan lainnya menggunakan suhu bertingkat, dengan skema pertama berupa 50°C (2 jam) diikuti 60°C (1,5 jam) dan 75°C (45 menit), serta skema kedua berupa 60°C (2 jam) diikuti 70°C (1 jam) dan 80°C (30 menit). Selama pengeringan dilakukan pengamatan terhadap perubahan massa, suhu bahan, dan warna stik porang. Data perubahan warna selanjutnya dianalisis dengan kinetika Avrami. Data suhu dan kadar air yang diperoleh digunakan untuk analisis h dan kp menggunakan metode Runge-Kutta. Selain itu, dilakukan analisis fisik meliputi kadar air, viskositas, pH, derajat putih, transparansi dan kelarutan, serta analisis kimia meliputi kadar abu, kadar glukomanan, dan kalsium oksalat. 

Hasil penelitian menunjukkan bahwa nilai h berkisar antara 141,463 – 246,840 W/m2°C, sedangkan nilai kp berkisar antara 22,908 – 33,731?/jam. Kualitas fisik stik porang meliputi kadar air antara 10,03 – 10,84% (wb) (kelas mutu I), viskositas antara 1733,33 – 733,33 mPa.s, pH antara 5,56 – 6,47, derajat putih antara 56,51 – 65,98%, konstanta laju perubahan warna antara 3,3 x 10-8 –1,3 x 10-2 %/menit, transparansi antara 0,23 – 0,69%, dan kelarutan antara 99,291 – 98,953%.. Kualitas kimia meliputi kadar abu antara 4,83 – 6,66% (kelas mutu II dan III), kadar glukomanan antara 55,92 – 43,4% (kelas mutu 1), dan kadar kalsium oksalat antara 162,0 – 896,4 mg/100 g.

Fresh porang is usually processed into dried porang chips before further processing. Insufficient contact with hot air due to the small cross-sectional area of the porang chips is one of the obstacles in the drying process. Porang sticks are one solution to maximize contact between the material and hot air, thereby optimizing the process and producing a high-quality product. This study aims to determine the convective heat transfer coefficient (h) and drying rate constant (kp) based on heat and mass transfer during the drying process of porang sticks using a cabinet dryer with stepped and constant temperature treatments, as well as product quality characterization.

Four drying temperature treatments were applied: two of them used constant temperatures, namely 50°C for 6 hours and 60°C for 4.5 hours; while the other two treatments used stepped temperatures, with the first scheme being 50°C (2 hours) followed by 60°C (1.5 hours) and 75°C (45 minutes), and the second scheme being 60°C (2 hours) followed by 70°C (1 hour) and 80°C (30 minutes). During drying, observations were made on changes in mass, material temperature, and color of the porang sticks. The color change data was then analyzed using Avrami kinetics. The temperature and moisture content data obtained were used for h and kp analysis using the Runge-Kutta method. Additionally, physical analysis was conducted, including moisture content, viscosity, pH, whiteness, transparency, and solubility, as well as chemical analysis, including ash content, glucomannan content, and calcium oxalate content. 

The results showed that the h value ranged from 141.463 – 246.840 W/m²°C, while the kp value ranged from 22.908 – 33.731?/hour. The physical quality of porang sticks includes moisture content between 10.03 – 10.84% (wb) (quality grades I), viscosity between 1733.33 – 733.33 mPa.s, pH between 5.56 – 6.47, whiteness between 56.51 – 65.98%, color change rate constant between 3.3 x 10-8 – 1.3 x 10-2 %/minute, transparency between 0.23 – 0.69%, and solubility between 99.291 – 98.953%. Chemical quality includes ash content between 4.83 – 6.66% (quality grades II and III), glucomannan content between 55.92% – 43.4% (quality grade I), and calcium oxalate content between 162.0 – 896.4 mg/100 g. 

Kata Kunci : Stik porang, konveksi, laju pengeringan, suhu, perpindahan panas, kualitas fisik dan kimia