Judul: Pemanfaatan Biji Kurma (Phoenix dactylifera L.) Sebagai Tepung dan Analisis Perubahan Mutunya Selama Penyimpanan
Abstrak: Date (Phoenix dactylifera L.) seeds can be processed into flour for cookies or any other food product. The production process of flour from the seeds are washing, sulphuring, blanching, drying, milling, and sieving. Date seed flour has a slightly brownish color with value degree of whiteness was about 53,83% and value of bulk density was about 0,43 g/ml. Furthermore, date seed flour contained 7,52% of moisture, 1,19% of ash, 5,03% of protein, 12,37% of fat, 12,74 % of crude fiber, 68,64% of carbohydrate, 37,63% of starch, and 2,42 ml of NaOH 0,1 N/100 g total of acid. The packaging of the flour is needed to maintain its quality during storage thus the flour are still good and fresh when it used for food products. This study was arranged in a Completely Randomize Design with factorial design with two replications. The first factor was packaging type (polyethylene plastic, plastic woven bag, and calico bag). The second factor was storage (0, 14, 21, 28, 42, 56 days). Data were analyzed using analysis of variance and differences between treatments were determined with Duncan test. The results showed that packaging type significantly affected the moisture content. Storage significantly affected the moisture content, fat content, crude fiber content, and carbohydrate content. Date seed flour were packed with calico bag had the highest increase of water content at about 3,23%, while the lowest increase of water content was owned by flour were packed with polyethylene plastic as much as 0.75%. If the water content of flour is high, meaning that the quality of flour will decrease and easily damage physically and biologically. This study concluded that the polyethylene plastic packs could minimize the deterioration quality of the flour and resulted on longer storage.
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Judul: Estimating the Shelf Life of Corn Flour with the Acceleration Method of Critical Moisture Content Approach
Abstrak: Tepung jagung adalah tepung yang didapatkan dengan cara menggiling biji jagung yang bersih melalui proses pemisahan kulit, endosperm, lembaga, dan tip cap. Salah satu UKM di Cibanteng, Kabupaten Bogor telah memproduksi tepung jagung kasar dan tepung jagung halus. Kedua jenis tepung tersebut harus memenuhi persyaratan mutu pangan sebelum dipasarkan dan dikonsumsi. Salah satu parameter mutu pangan penting yang ada adalah keamanan pangan yang ditunjukan dengan pencantuman tanggal kadaluarsa. Tanggal kadaluarsa dapat ditentukan dengan menduga umur simpan tepung jagung menggunakan metode ASLT dengan pendekatan kadar air kritis. Hasil penelitian menunjukkan bahwa tepung jagung menghasilkan kadar air kesetimbangan yang berbeda-beda pada RH yang berbeda. Tepung jagung cenderung mengalami desorpsi pada RH 32 dan 54%, serta adsorpsi pada RH 75, 84, dan 93%. Proses adsorpsi dan desorpsi menghasilkan kurva ISA tepung jagung berbentuk sigmoid. Kurva ISA yang dihasilkan dimuluskan dengan kurva dari model terpilih yaitu Model Chen Clayton. Dugaan umur simpan tepung jagung dengan kemasan alumunium foil pada RH 78 dan 82% berturut-turut selama 28 dan 22 hari. Sedangkan umur simpan tepung jagung dengan kemasan PE pada RH 78 dan 82% selama 2 hari. Umur simpan yang dihasilkan sangat pendek sehingga perlu dilakukan proses pengeringan untuk memperpanjang umur simpan tepung jagung., Corn flour is flour obtained by grinding clean corn kernels through a process of separating the husk, endosperm, institutions, and tip cap. One of the SMEs in Cibanteng, Bogor Regency has produced coarse corn flour and fine corn flour. Both types of flour must meet food quality requirements before being marketed and consumed. One of the important food quality parameters that exist is food safety as indicated by the inclusion of the expiration date. The expiration date can be determined by estimating the shelf life of corn flour using the ASLT method with a critical moisture content approach. The results showed that corn flour produced different equilibrium moisture content at different RH. Corn flour tends to experience desorption at RH 32 and 54%, and adsorption at RH 75, 84, and 93%. The adsorption and desorption processes resulted in a sigmoid ISA curve of corn flour. The resulting ISA curve is smoothed with the curve of the selected model, namely the Chen Clayton Model. Alleged shelf life of corn flour with aluminum foil packaging at RH 78 and 82%, respectively, for 28 and 22 days. While the shelf life of corn flour with PE packaging at RH 78 and 82% for 2 days. The shelf life of the resulting product is very short, so it is necessary to do a drying process to extend the shelf life of corn flour.
Keyword: Kadar Air Kesetimbangan, Kadar Air Kritis, Umur Simpan, RH, Tepung Jagung

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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