Electronic Theses and Dissertation

Umbi janeng (Dioscorea hispida Dennst) merupakan komoditas pangan lokal di Aceh yang berpotensi sebagai sumber karbohidrat alternatif. Perajangan umbi janeng secara manual menghasilkan irisan yang tidak seragam dan memerlukan waktu lama hingga 6 menit per kilogram sehingga menghambat efisiensi dan mutu pengolahan. Untuk mengatasi masalah ini diperlukan pengembangan mesin perajang yang mampu meningkatkan produktivitas, konsistensi ukuran irisan, dan mutu bahan olahan pada skala rumah tangga dan UMKM.
Penelitian ini bertujuan mengevaluasi kinerja teknis dan kelayakan ekonomi mesin perajang janeng. Rancangan percobaan menggunakan Rancangan Acak Lengkap (RAL) faktorial dua faktor, yakni jarak mata pisau (2 mm dan 4 mm) dan ukuran pulley (4, 6, dan 8 inch) dengan tiga ulangan, untuk mengukur kapasitas kerja aktual, efisiensi mesin, serta persentase hasil rajangan sempurna, tidak sempurna, dan tidak terajang. Penelitian ini dilaksanakan pada bulan Oktober-Desember 2025 di Laboratorium Perbengkelan dan Laboratorium Alat Mesin Pertanian, Program Studi Teknik Pertanian, Fakultas Pertanian, Universitas Syiah Kuala, serta di Desa Riting, Kecamatan Indrapuri, Kabupaten Aceh Besar. Penelitian menggunakan Rancangan Acak Lengkap (RAL) faktorial dengan dua faktor, yaitu jarak mata pisau (2 mm dan 4 mm) dan ukuran pulley (4, 6, dan 8 inci), sehingga diperoleh enam kombinasi perlakuan dengan tiga kali ulangan. Pengujian meliputi pengukuran kualitas hasil rajangan, kapasitas, efisiensi, serta analisis kelayakan ekonomi mesin. Data dianalisis menggunakan analisis ragam (ANOVA) dengan bantuan perangkat lunak SPSS untuk mengetahui pengaruh perlakuan terhadap kinerja mesin perajang janeng.
Hasil penelitian menunjukkan bahwa jarak mata pisau dan ukuran pulley berpengaruh sangat nyata terhadap kualitas hasil rajangan umbi janeng (p < 0,001) dengan nilai R² = 0,996, yang berarti model mampu menjelaskan 99,6% variasi respons. Kombinasi terbaik adalah mata pisau 2 mm dengan pulley 6 inch (M₁P₂), menghasilkan efisiensi mesin 87,99%, persentase rajangan sempurna >90%, rajangan tidak sempurna 3,50%, dan tidak terajang 0,33%. Meskipun pulley 4 inch memberikan kapasitas kerja tertinggi (206,3 kg/jam), pulley 6 inch lebih optimal karena menyeimbangkan kecepatan putar, gaya potong, dan stabilitas mesin sehingga kualitas rajangan lebih baik. Dari aspek ekonomi, mesin pada perlakuan terbaik (kapasitas ≈153 kg/jam) dinyatakan sangat layak dikembangkan dengan biaya operasional Rp86,03/kg, BEP 10.603,3 kg, dan payback period 1,8 tahun dari investasi awal RP 3.000.000, sehingga cocok sebagai teknologi tepat guna untuk meningkatkan efisiensi dan produktivitas pengolahan umbi janeng pada skala UMKM.

**Janeng tuber** (*Dioscorea hispida* Dennst.) is a local food commodity in Aceh with significant potential as an alternative carbohydrate source. Manual slicing of janeng tubers produces non-uniform slices and requires a relatively long processing time of up to 6 minutes per kilogram, thereby reducing processing efficiency and product quality. To address this issue, the development of a slicing machine is required to improve productivity, slice uniformity, and the quality of processed products for household and small-to-medium enterprise (SME) applications. This study aimed to evaluate the technical performance and economic feasibility of a janeng tuber slicing machine. The experiment employed a two-factor factorial Completely Randomized Design (CRD), consisting of blade spacing (2 mm and 4 mm) and pulley diameter (4, 6, and 8 inches), with three replications. The evaluated parameters included actual working capacity, machine efficiency, and the percentages of perfectly sliced, imperfectly sliced, and unsliced tubers. The research was conducted from October to December 2025 at the Workshop Laboratory and Agricultural Machinery Laboratory, Department of Agricultural Engineering, Faculty of Agriculture, Universitas Syiah Kuala, and in Riting Village, Indrapuri District, Aceh Besar Regency. Six treatment combinations were obtained from the two experimental factors, each replicated three times. Machine performance evaluation included measurements of slicing quality, working capacity, efficiency, and economic feasibility. The data were analyzed using analysis of variance (ANOVA) with SPSS software to determine the effects of the treatments on the performance of the janeng tuber slicing machine. The results showed that blade spacing and pulley diameter had a highly significant effect on the slicing quality of janeng tubers (*p* < 0.001), with an R² value of 0.996, indicating that the model explained 99.6% of the variation in the response. The best treatment combination was a 2 mm blade spacing with a 6-inch pulley (M₁P₂), which achieved a machine efficiency of 87.99%, more than 90% perfectly sliced tubers, 3.50% imperfectly sliced tubers, and only 0.33% unsliced tubers. Although the 4-inch pulley produced the highest working capacity (206.3 kg h⁻¹), the 6-inch pulley provided the optimum balance between rotational speed, cutting force, and machine stability, resulting in superior slicing quality. From an economic perspective, the machine under the best treatment (capacity ≈153 kg h⁻¹) was considered highly feasible for practical implementation, with an operating cost of IDR 86.03 kg⁻¹, a break-even point (BEP) of 10,603.3 kg, and a payback period of 1.8 years based on an initial investment of IDR 3,000,000. These findings indicate that the developed machine is an appropriate technology for improving the efficiency and productivity of janeng tuber processing, particularly for household industries and small and medium enterprises (SMEs).