Judul: Mutu Mikrobiologi dan Organoleptik Daging Sapi Panggang dengan Penambahan Kecombrang dan Waktu Marinasi 1 atau 12 Jam
Abstrak: Daging sapi panggang memerlukan upaya pada proses pengolahannya sehingga dapat meminimalkan kerusakan akibat mikroba dan mempunyai aspek sensorik yang dapat diterima oleh masyarakat. Penelitian ini bertujuan mempelajari pengaruh formula bumbu yang diberi penambahan kecombrang dengan marinasi jangka singkat atau panjang terhadap sifat mikrobiologi dan organoleptik daging sapi panggang. Rancangan yang digunakan dalam penelitian ini adalah rancangan acak kelompok (RAK) pola faktorial 3 x 2 dengan 3 kelompok periode pembuatan. Faktor pertama adalah penggunaan formula bumbu marinasi (tanpa bumbu, bumbu tanpa penambahan kecombrang, atau bumbu dengan penambahan kecombrang). Faktor kedua adalah lama marinasi (1 atau 12 jam). Hasil penelitian menunjukkan bahwa penambahan kecombrang pada bumbu marinasi tidak berpengaruh nyata terhadap mutu mikrobiologi namun berpengaruh nyata terhadap mutu organoleptik daging sapi panggang pada atribut warna dan rasa. Lama marinasi diantara 1 jam dan 12 jam pada daging sapi tidak berbeda secara signifikan terhadap mutu sensori maupun penghambatan pada pertumbuhan mikroba pada daging sapi panggang. Sebagai kesimpulan, marinasi selama 1 jam efektif dilakukan untuk bumbu tanpa maupun dengan penambahan kecombrang berdasarkan pertimbangan efisiensi waktu marinasi dalam pembuatan daging sapi panggang., Grilled beef requires proper processing method to minimize damaged caused by microorganisms and have sensory aspects that are acceptable by society. This study aimed to investigate the effects of marinade seasoning formula with the addition of torch ginger and short term or long term marination period on the microbiological and sensory properties of grilled beef. This study used randomized block design with a 3 x 2 factorial pattern and 3 groups of producing period. The first factor was the use of marinade formula (without marinade, marinade without torch ginger, marinade with adding torch ginger). The second factor was the length of marinating time (1 or 12 hours). The results showed that the addition of torch ginger in the marinade seasoning did not have a significant effect on the microbiological characteristics but had a significant effect on the sensory properties of grilled beef in terms of color and taste attributes. The marinating time between 1 hour and 12 hours on beef did not have a significant effect on sensory characteristics or inhibition of microbe growth in grilled beef. In conclusion, 1 hour marinating period was effective for both seasoning without or with torch ginger based on considerations of marinating time efficiency in the production of grilled beef.
Keyword: grilled beef, marinade, marinating time, torch ginger

Judul: Microbiology and Sensory Properties of Grilled Beef Marinated with Etlinga elatior addition and Marination Time 12 or 24 Hours
Abstrak: Penelitian ini bertujuan menganalisis sifat mikrobiologi dan organoleptik daging sapi panggang yang diberi penambahan kecombrang pada bumbu dan waktu marinasi 12 atau 24 jam. Rancangan yang digunakan pada penelitian ini adalah rancangan acak kelompok (RAK) pola faktorial. Faktor pertama adalah metode marinasi, yaitu daging sapi yang dimarinasi tanpa bumbu (kontrol), dimarinasi dengan bumbu tanpa penambahan kecombrang (bumbu standar), atau dimarinasi bumbu dengan penambahan kecombrang 10%. Faktor kedua adalah waktu marinasi 12 atau 24 jam. Berdasarkan hasil penelitian daging sapi yang dimarinasi bumbu marinasi dengan atau tanpa penambahan bunga kecombrang tidak berpengaruh terhadap sifat mikrobiologi daging panggang jika dibandingkan dengan kontrol. Penambahan bumbu marinasi berpengaruh nyata terhadap sifat sensori daging sapi panggang pada parameter warna, aroma, keempukan, penampilan umum, dan rasa jika dibandingkan dengan kontrol. Waktu terbaik dalam proses marinasi dengan bumbu tanpa penambahan kecombrang adalah 24 jam dan yang diberi penambahan bunga kecombrang adalah 12 jam., The objective of the study was to analyze the microbiology and sensory properties of grilled beef with the addition of Etlinga elatior flower (EEF) to seasoning and a marination time of 12 or 24 hours. The study was designed use randomized block design (RBD) factorial. The first factor was marination treatment, namely beef marinated without seasoning (control), marinated with the seasoning without EEF addition, or marinated with seasoning plus EEF 10%. The second factor was the length of marination 12 or 24 hours. The results showed the addition of marinated seasoning with or without EEF did not have an effect on the microbiology properties of grilled beef compared to the control. The addition of marinade seasoning had a significant effect on the sensory properties of grilled beef on colour, aroma, tenderness, general appearance, and taste parameter. The best marination duration for marination using seasoning without EEF was 24 hours and for seasoning with EEF was 12 hours.
Keyword: Daging Sapi Panggang, Kecombrang, Waktu Marinasi, Organoleptik, Mikrobiologi, Sensori

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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