Judul: The Effect of Palm Sugar and Tamarind on The Quality of Tempe Orek During Storage
Abstrak: Tempe orek merupakan produk olahan tempe yang umum ditemui di Indonesia. Tempe orek umumnya dibuat dalam jumlah banyak untuk pemakaian berulang yang disimpan pada suhu ruang. Gula merah dan asam jawa yang merupakan bumbu utama dalam pembuatan tempe orek menjadi faktor penting dalam memengaruhi kualitas produk selama penyimpanan. Penelitian ini bertujuan untuk menganalisis pengaruh interaksi perlakuan gula merah, asam jawa, dan lama penyimpanan terhadap mutu tempe orek, serta mengukur profil sensori, tingkat kesukaan, dan komposisi kimia dari tempe orek terbaik. Mutu tempe orek yang diuji, yaitu kadar air, pH, tekstur, angka lempeng total (ALT), dan angka kapang khamir (AKK). Perlakuan terbaik ditentukan dengan metode skoring serta pengujian sensori Rate-all-that-apply (RATA), rating hedonik, dan uji proksimat. Kombinasi perlakuan gula merah, asam jawa, dan lama penyimpanan berpengaruh nyata terhadap parameter kadar air dan pH. Perlakuan terbaik diperoleh pada konsentrasi gula merah 50% dan asam jawa 2,50%. Pada perlakuan tersebut diperoleh nilai kadar air, pH, kekerasan, ALT, dan AKK yang menunjukkan bahwa tidak terjadi penurunan mutu tempe orek yang signifikan selama penyimpanan. Namun, terjadi penurunan intensitas atribut dan tingkat kesukaan terhadap tempe orek dengan perlakuan terbaik selama penyimpanan., Tempe orek is a processed tempe product that is commonly found in Indonesia. Tempe orek is generally made in large quantities for repeated use and stored at room temperature. Palm sugar and tamarind are the main spices and the important factors in influencing the quality of product during storage. This research aims to analyze the interactions of palm sugar, tamarind, and storage time on affecting the quality of tempe orek, and to measure the sensory profile and chemical composition of the best tempe orek. Water content, pH, texture, total plate count (TPC), and the total yeast and mold count (TYMC) were tested as the quality parameters. The best tempe orek was determined using the scoring method, and Rate-all-that-apply (RATA), hedonic rating, and proximate were tested. The interaction of palm sugar, tamarind, and storage time had a significant effect on water content and pH. Sample with concentration of 50% palm sugar and 2,50% tamarind were the best tempe orek. In this sample, the value of water content, pH, hardness, TPC, and TYMC showed that there was no significant decrease in the quality of tempe orek during storage. However, there was a decrease in the attribute intensity and the preference of the best tempe orek during storage.
Keyword: palm sugar, quality, storage, tamarind, tempe orek

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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