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: Physical, Chemical, Sensory Characteristics, and Shelf Life of Tempe Chips
Abstrak: Keripik tempe merupakan salah satu bentuk diversifikasi dari pengolahan tempe sehingga produk tempe lebih awet. Di Indonesia, jenis keripik tempe yang beredar di pasaran adalah keripik tempe konvensional dan keripik tempe tapioka. Penelitian ini bertujuan membandingkan karakteristik fisik, kimia, dan sensori serta menentukan umur simpan keripik tempe yang dikemas dalam kemasan standing pouch aluminum foil. Analisis dilakukan dengan membandingkan keripik tempe produksi Rumah Tempe Azaki dengan keripik tempe komersial yang sudah beredar di pasaran yang akan dijadikan sebagai kontrol. Hasil penelitian ini menunjukkan bahwa semakin tinggi proporsi tapioka yang digunakan sebagai bahan baku, maka semakin tinggi nilai oHue, kerenyahan, kadar karbohidrat, dan penilaian panelis terhadap karakteristik sensorinya. Selain itu, semakin tinggi proporsi kedelai yang digunakan sebagai bahan baku, maka semakin tinggi kadar abu, kadar lemak, kadar protein, dan kadar serat kasar. Keripik tempe tapioka dengan perbandingan kedelai dan tapioka sebesar 50:50 (b:b) cenderung lebih disukai dari segi warna, aroma, rasa, tekstur, dan keseluruhan, sedangkan keripik tempe konvensional cenderung kurang disukai dibandingkan kontrol (komersial). Umur simpan keripik tempe tapioka dan keripik tempe konvensional ditentukan berdasarkan parameter kritis kadar asam lemak bebas. Umur simpan keripik tempe tapioka yang dikemas dalam kemasan standing pouch aluminum foil pada suhu 27 dan 30 oC berturut-turut selama 71 dan 69 hari. Umur simpan keripik tempe konvensional yang dikemas dalam kemasan standing pouch aluminum foil pada suhu 27 dan 30 oC berturut-turut selama 68 dan 66 hari, Tempe chips are one of diversification of tempe processing so that tempe products are more durable. In Indonesia, the types of tempe chips on the market are conventional tempe chips and tapioca tempe chips. This study examines to compare the physical, chemical, and sensory characteristics and determine the shelf life of tempe chips that packaged in standing pouch aluminum foil. The analysis was carried out by comparing tempe chips produced by Rumah Tempe Azaki with commercial tempe chips already sold in the market which will be used as control. The results of this study showed that the higher the proportion of tapioca used as raw material, increased oHue values, crispness, carbohydrate content, and panelists assessment of sensory characteristics. In addition, the higher the proportion of soybean used as raw material, increased the ash content, fat content, protein content, and crude fiber content. Tapioca tempe chips with a ratio of 50:50 (w:w) soybean and tapioca tend to be preferred in terms of color, aroma, taste, texture, and overall, while conventional tempe chips tend to be less favorable than control (commercials). The shelf life of tapioca tempe chips and conventional tempe chips was determined based on the critical parameter of free fatty acid content. The shelf life of tapioca tempe chips that packaged in standing pouch aluminum foil at temperatures of 27 and 30 oC was 71 and 69 days respectively. The shelf life of conventional tempe chips that packaged in standing pouch aluminum foil at a temperature of 27 and 30 oC for 68 and 66 days respectively
Keyword: fisik, keripik tempe konvensional, keripik tempe tapioka, kimia, umur simpan, physical, conventional tempe chips, chemical, shelf life, tapioca tempe chips

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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