Judul: Shelf-Life Estimation of Coriander Seed Powder Based on Critical Moisture Content Approach
Abstrak: Bubuk ketumbar bersifat higroskopis, yakni memiliki kemampuan menyerap uap air dengan baik. Penyerapan uap air dari lingkungan oleh bubuk ketumbar selama penyimpanan akan menyebabkan bubuk mudah rusak dan mempersingkat umur simpan. Tujuan penelitian ini adalah (1) mengidentifikasi kadar air kesetimbangan bubuk ketumbar pada kelembapan relatif (RH) yang berbeda, (2) mengidentifikasi model kurva isotermis sorpsi air bubuk ketumbar, dan (3) menduga umur simpan bubuk ketumbar. Tahapan penelitian dimulai dengan pembuatan bubuk ketumbar, kemudian penentuan kadar air kesetimbangan, dan perhitungan umur simpan bubuk ketumbar. Proses pembuatan bubuk ketumbar adalah sortasi, penyangraian biji dengan api kecil, wind drying, penggilingan, dan pengayakan. Kelembapan relatif (RH) yang diinginkan didapatkan dari larutan jenuh garam MgCl2, NaBr, NaCl, KCl dan KNO3. Data kadar air kesetimbangan dan aktivitas air (aw) diplotkan untuk mendapatkan model kurva isotermis sorpsi. Hasil penelitian menunjukkan bahwa kadar air kesetimbangan pada RH 32%, 56%, 75%, 84%, dan 93% berturut-turut adalah 6,96; 8,96; 12,78; 16,4; dan 21,73 (% bk). Model Hasley adalah model yang paling tepat menggambarkan kurva isotermis sorpsi bubuk ketumbar dengan nilai MRD 3,05 dan nilai koefisien determinasi (R2) 0,9926. Kadar air kritis bubuk ketumbar adalah 12,11 (% bk). Umur simpan bubuk ketumbar pada ruang penyimpanan RH 87,5% dan suhu 30℃ adalah 820 hari (27,3 bulan) menggunakan kemasan aluminum foil dan 431 hari (14,3 bulan) menggunakan kemasan PP (polypropylene) ketebalan 0,03 mm., Coriander seed powder is hygroscopic, which has the ability to absorb moisture well. Coriander seed powder's absorption from the environment during storage will cause the powder to deteriorate easily and shorten its shelf-life. This study aims to (1) identify the equilibrium moisture content of coriander seed powder at different relative humidity (RH), (2) identify the moisture sorption isotherms curve model of coriander seed powder, and (3) estimate the shelf-life of coriander seed powder. The research stage begins with the production of coriander seed powder, then the determination of equilibrium moisture content at various RH, and the calculation of the shelf-life of coriander seed powder. The procedure of producing coriander seed powder is sorting, roasting seeds over low heat, wind drying, grinding, and sieving. The necessary relative humidity (RH) was achieved from a saturated solution of the salts MgCl2, NaBr, NaCl, KCl, and KNO3. The equilibrium moisture content and moisture activity (aw) data are plotted to obtain a model of the moisture sorption isotherm equation. The results showed that the equilibrium moisture content at RH 32%, 56%, 75%, 84%, and 93% was 6.96; 8.96; 12.78; 16.4; and 21.73 (%db). The Hasley model is the best model to describe the sorption isotherm curve of coriander seed powder with an MRD value of 3.05 and a coefficient of determination (R2) value of 0.9926. The critical moisture content of coriander seed powder is 12.11 (%db). The shelf-life of coriander seed powder at the storage room with RH 87.5% and temperature of 30°C was 820 days (27.3 months) using aluminum foil packaging and 431 days (14.3 months) using 0.03 mm thick PP (polypropylene) packaging.
Keyword: coriander seed powder, critical moisture content, sorption isotherm curve, shelf-life