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: Determination of Shelf Life of Fried Chicken Flour with Critical Moisture Content Approach Method (Labuza Method)
Abstrak: Tepung bumbu mengandung dua atau lebih rempah dengan atau tanpa penambahan bahan pangan lain. Pengolahan menjadi bentuk tepung dapat mencegah terjadinya kerusakan dan memperpanjang umur simpan. Salah satu faktor penting yang mempengaruhi kualitas bahan baku adalah water activity dan relative humidity. Penentuan umur simpan menggunakan metode accelerated shelf-life testing (ASLT) dengan pendekatan kadar air kritis (labuza). Model persamaan yang digunakan dalam penelitian ini adalah Hasley, Chen-Clayton, Henderson, Caurie, dan Oswin. Penelitian ini bertujuan untuk mengetahui kadar air kesetimbangan tepung, pemodelan kurva isotermis sorpsis yang paling tepat, dan lama umur simpan produk. Penyimpanan dilakukan pada 5 RH yang berbeda pada suhu 30oC. Model persamaan terpilih yaitu model Caurie dengan nilai slope 0,9922. Model Caurie digunakan untuk menentukan umur simpan tepung pada kemasan LDPE, PP, dan alumunium foil. Hasil penentuan umur simpan pada aw 0,75 menggunakan kemasan LDPE (1 bulan), PP (3,9 bulan), dan alumunium foil (25,4 bulan); dan pada aw 0,84 menggunakan kemasan LDPE (0,6 bulan), PP (2,2 bulan), dan alumunium foil (14,4 bulan)., Seasoned flour contains two or more spices with or without the addition of other food ingredients. Processing into flour can prevent damage and extend shelf life. One of the important factors that affect the quality of raw materials is water activity and relative humidity. Determination of shelf life using the accelerated shelf-life testing (ASLT) method with a critical moisture content (labuza) approach. The equation model used in this research is Hasley, Chen-Clayton, Henderson, Caurie, and Oswin. This study aims to determine the equilibrium moisture content of flour, the most appropriate modeling of the sorption isothermic curve, and the shelf life of the product. Storage was carried out at 5 different RH at 30oC. The selected equation model is the Caurie model with a slope value of 0,9922. The Caurie model was used to determine the shelf life of flour in LDPE, PP, and aluminum foil packaging. The results of determining shelf life at aw 0,75 using LDPE (1 month), PP (3,9 months), and aluminum foil (25,4 months) and at aw 0,84 using LDPE (0,6 months), PP (2,2 months), and aluminum foil (14,4 months).
Keyword: kadar air kritis, labuza, tepung ayam goreng, umur simpan

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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