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: Microbiological and Organoleptic Properties of Grilled Shortplate Beef with Different Seasoning Formulation and Short Marination Time
Abstrak: The development of marination methods is one of the ways that serves to reduce bacterial content and maintain the quality of beef. This study aims to analyze the influence of adding torch ginger (kecombrang) to the marinade with different short marination times on the microbiological and organoleptic properties of roasted beef. The study used a 3x2 factorial randomized block design. The first factor was different beef marinade spices, namely: without spices, marination without torch ginger, and marination with the addition of torch ginger. The second factor was the marination time, either 30 or 60 minutes. The results of the microbiological test showed that adding marinade spices with or without torch ginger did not significantly differ. However, the organoleptic test indicated that there was an increased preference of the panelists for color, aroma, taste, tenderness, and overall appearance with all marination times (p<0.05). The addition of torch ginger did not affect the microbiological properties of roasted beef but did influence the organoleptic properties of roasted beef in all short marination times., Pengembangan metode marinasi merupakan salah satu cara yang berfungsi untuk mengurangi kandungan bakteri dan menjaga kualitas daging sapi. Penelitian ini bertujuan menganalisis pengaruh penambahan kecombrang pada bumbu dengan lama waktu marinasi singkat yang berbeda terhadap sifat mikrobiologi dan organoleptik daging sapi panggang. Penelitian ini menggunakan rancangan acak kelompok faktorial 3x2. Faktor pertama adalah bumbu marinasi daging yang berbeda, yaitu: tanpa bumbu, marinasi tanpa kecombrang, dan marinasi dengan penambahan kecombrang. Faktor kedua adalah lama waktu marinasi yaitu: 30 atau 60 menit. Hasil uji mikrobiologi menunjukkan bahwa penambahan bumbu marinasi tanpa kecombrang atau dengan kecombrang tidak berbeda nyata. Namun, pada uji organoleptik menunjukkan bahwa terdapat peningkatan kesukaan panelis terhadap warna, aroma, rasa, keempukan, dan penampilan umum dengan semua waktu marinasi (p<0,05). Penambahan kecombrang tidak berpengaruh pada sifat mikrobiologis daging sapi panggang, namun berpengaruh pada sifat organoleptik daging sapi panggang pada semua waktu marinasi singkat.
Keyword: grilled beef, marinades, microbiological properties, organoleptic properties

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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