Judul: Nutritional Analysis and Shelf Life Estimation of  Banana Chips by Accelerated Shelf-Life Testing (ASLT)
Abstrak: Produk yang ingin diperdagangkan di Indonesia harus memiliki label pada kemasannya. Keterangan yang wajib dicantumkan pada label adalah tanggal kadaluarsa produk. Informasi nilai gizi merupakan informasi penting bagi konsumen karena dapat mempengaruhi pola makan konsumen. Tujuan penelitian ini adalah menganalisis komposisi gizi, mengidentifikasi perubahan mutu pada berbagai suhu, dan menghitung umur simpan produk keripik pisang. Analisis gizi dilakukan menggunakan metode analisis proksimat terhadap tiga varian rasa keripik pisang. Perubahan mutu yang diamati adalah susut bobot, kadar air, kadar asam lemak bebas (%FFA), dan mutu organoleptik keripik pisang yang disimpan pada suhu kamar (30±1° C), 40±1° C, dan 50±1° C. Umur simpan dihitung menggunakan metode Accelerated Shelf-Life Testing (ASLT) melalui persamaan Arrhenius. Seratus gram keripik pisang rasa balado, sapi panggang, dan jagung bakar masing- masing mengandung air 2.80 g, 2.54 g, dan 2.62 g; karbohidrat 69.77 g, 67.49 g, dan 71.25 g; protein 1.05 g, 1.38 g, dan 1.05 g; lemak 22.58 g, 23.18 g, dan 21.78 g; serta energi total 486.47 kkal, 474.50 kkal, dan 470.19 kkal. Perubahan mutu yang terjadi adalah kenaikan bobot keripik, kadar air, dan kadar asam lemak bebas serta penurunan tingkat kesukaan terhadap keripik pisang. Umur simpan keripik pisang adalah 265 hari pada suhu penyimpanan 25°C., A product traded in Indonesia must have a label on its packaging. Information that must have included is its expired date. Nutritional information is important for consumers because it could relate to the consumer dietary patterns. The purpose of this study was to analyze nutrient composition, identify quality changes at various temperatures, and calculate the shelf life of banana chips. Nutritional analysis was carried to proximate analysis in three flavors of banana chips. Quality changes observed included weight loss, moisture content, free fatty acid levels (%FFA), and organoleptic at room temperature (30±1°C), 40±1°C, and 50±1°C. The shelf life of the product estimated with Accelerated Shelf-Life Testing (ASLT) method. A hundred grams of balado, barbecue, and roasted corn flavored banana chips respectively contains water 2.80 g, 2.54 g, and 2.62 g; carbohydrates 69.77 g, 67.49 g and 71.25 g; protein 1.05 g, 1.38 g, and 1.05 g; fat of 22.58 g, 23.18 g, and 21.78 g; and total energy 486.47 kcal, 474.50 kcal, and 470.19 kcal. Quality changes that occur are an increase in the weight of chips, moisture content, and levels of freefatty acids and a decrease in the level of preference for banana chips. The shelf life of banana chips is 265 days at storage temperature of 25°C.
Keyword: accelerated shelf-life testing, banana chips, nutrition fact, shelf life

Judul: Estimation of Shelf Life Banana Chips “Barong Chips” with the Accelerated Shelf-Life Testing (ASLT) Method
Abstrak: Keripik pisang “Barong Chips” merupakan salah satu produk olahan pisang dari Desa Klirong, Kecamatan Klirong, Kabupaten Kebumen, Jawa Tengah. Keripik pisang dapat mengalami penurunan mutu selama penyimpanan akibat pengaruh kondisi lingkungan seperti RH, oksigen, kemasan, dan suhu penyimpanan, sehingga perlu dilakukan pencantuman informasi umur simpan. Penelitian ini bertujuan mengetahui karakteristik awal, mengidentifikasi penurunan mutu selama penyimpanan, dan melakukan pendugaan umur simpan. Pengamatan dilakukan terhadap produk yang dikemas menggunakan plastik polypropylene dengan tebal 0,05 dan 0,08 mm, pada tiga suhu yaitu 25 , 35 , dan 45ºC selama 8 minggu. Parameter yang diamati yaitu kadar air, asam lemak bebas (FFA), kekerasan, dan kecerahan warna setiap 7 hari sekali. Karakteristik awal keripik pisang yang digunakan memenuhi SNI 01-4315-1996, kecuali kadar lemak. Hasil penelitian menunjukan perubahan mutu berupa peningkatan kadar air dan FFA, serta penerimaan panelis. Pendugaan umur simpan dilakukan berdasarkan parameter yang menyebabkan produk cepat rusak yaitu laju peningkatan kadar air. Umur simpan keripik pisang “Barong Chips” pada suhu ruang (30ºC) yaitu 84 hari., “Barong Chips” is one of banana chips produced by a small scale enterprise Klirong Village, Kebumen, Central Java. Banana chips quality will decrease during storage time due to the influence of environmental conditions such as RH, oxygen, packaging, and storage temperature, so it is necessary to include information on shelf life. The study objective are determining the initial characteristics of “Barong chips”, identifying its quality changes during storage time, and estimating its shelf life. The research was conducted by storing the product that packed in 0,05 and 0,08 thickness polyprophylene film, at three level of temperatures, i.e. 25 , 35 , and 45ºC for 8 weeks. The parameters observed were moisture content, free fatty acid (FFA), hardness, and color brightness every 7 days. The initial characteristics are appropriate to quality standards, except for fat. The result showed changes in the form of an increase in water content and FFA, as well as panelist acceptance. Estimation of shelf life is carried out based on the parameters that cause the product to spoil quickly, the rate of increase air content. The shelf life of “Barong Chips” banana chips at room temperature (30ºC) is 84 days.
Keyword: ASLT, “Barong Chips”, packaging, shelf life

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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