Judul: Physical Properties, Organoleptic, and Total Lactic Acid Bacteria of Yogurt with the Addition of Ambon Banana Fruit Puree (Musa paradisiaca L.)
Abstrak: Yoghurt merupakan hasil olahan susu dari fermentasi bakteri asam laktat (BAL) yaitu Streptococcus thermophilus dan Lactobacillus bulgaricus. Buah pisang ambon memiliki rasa yang manis dan kandungan gizi yang tinggi. Penelitian ini bertujuan menganalisis sifat fisik (nilai pH, viskositas, dan total asam tertitrasi), organoleptik (intensitas kecerahan, cita rasa, kekentalan, serta aroma), dan total bakteri asam laktat pada yoghurt dengan penambahan pure buah pisang ambon. Persentase puree buah pisang ambon yang ditambahkan ke yoghurt yaitu 0%, 5%, dan 10%. Rancangan yang digunakan dalam penelitian ini adalah rancangan acak lengkap (RAL) dengan tiga kali ulangan. Hasil penelitian menunjukkan bahwa penambahan buah pisang ambon pada yoghurt berpengaruh nyata (P<0,05) terhadap nilai viskositas dan uji mutu hedonik pada sifat organoleptik yoghurt, tetapi tidak berpengaruh nyata (P>0,05) terhadap nilai pH, total asam tertitrasi (TAT), uji hedonik parameter aroma pada sifat organoleptik yoghurt dan total BAL. Persentase terbaik ditemukan pada perlakuan penambahan buah pisang ambon sebanyak 10%., Yogurt is a dairy product from the fermentation of lactic acid bacteria (LAB), namely Streptococcus thermophilus and Lactobacillus bulgaricus. Ambon banana fruit has a sweet taste and high nutritional content. This study aims to analyze the physical properties (pH value, viscosity, and total titratable acid), organoleptic (intensity of brightness, taste, viscosity, and aroma), and total lactic acid bacteria in yogurt with the addition of ambon banana fruit puree. The percentage of banana puree added to yogurt was 0%, 5%, and 10%. The design used in this study was a complete randomized design (RAL) with three replications. The results showed that the addition of ambon banana fruit to yogurt had a significant effect (P<0,05) on the viscosity value and hedonic quality test on the organoleptic properties of yogurt, but no significant effect (P>0,05) on pH value, total titratable acid (TAT), hedonic test of aroma parameters on the organoleptic properties of yogurt and total LAB. The best percentage was found in treatment of adding 10% ambon banana fruit.
Keyword: lactic acid bacteria, yogurt, ambon banana fruit puree, organoleptic, physical properties

Judul: Physical and Organoleptic Properties of Probiotic Yogurt With The Addition of Red Fruit (Pandanus conoideous L.).
Abstrak: Yogurt can be made from homogenized milk, low-fat milk or skimmed milk with the addition of powdered milk. Starter culture commonly used in yogurt is Lactobacillus bulgaricus and Streptococcus thermophillus can not survive in environments with high acidity, so probiotics needed. One of the fruits that can be used in the process of making yogurt is red fruit (Pandanus Conoideus L). The observed physical characteristics consist of pH, viscosity, total acid concentration and water activity (aw) and organoleptic arachnids observed consisting of color, flavour, aroma and consistency. This research using a complete randomized design (RAL. The results showed that the addition of red fruit has a real effect (P<0.05) on pH, viscosity and total acid titrated and organoleptic test shows the addition of red fruit has a noticeable effect on color, flavour, aroma and viscosity in hedonic quality tests, then in hedonic tests affect aroma and flavour. Based on the results of yogurt testing with the addition of 2.5% this is the closest to control and acceptable to indonesian national standards (SNI)., Yogurt dapat dibuat dari susu yang telah dihomogenisasi, susu berkadar lemak rendah atau susu skim dengan penambahan susu bubuk. Kultur starter yang biasa digunakan dalam yogurt yaitu Lactobacillus bulgaricus dan Streptococcus thermophillus tidak dapat bertahan pada lingkungan dengan keasaman yang tinggi, sehingga diperlukan probiotik. Salah satu buah yang dapat ditambahkan adalah buah merah (Pandanus Conoideus L). Karakteristik fisik yang diamati terdiri atas pH, viskositas, total asam tertitrasi dan aktivitas air (aw) serta karakteristik organoleptik yang diamati terdiri atas warna, flavour, aroma dan kekentalan. Penelitian dilakukan dengan menggunakan rancangan acak lengkap (RAL). Hasil penelitian menunjukan bahwa penambahan buah merah berpengaruh nyata (P<0,05) terhadap pH, viskositas dan total asam tertitrasi. Uji organoleptik memperlihatkan penambahan buah merah berpengaruh nyata terhadap warna, flavour, aroma dan kekentalan pada uji mutu hedonik, lalu pada uji hedonik berpengaruh pada aroma dan flavour. Berdasarkan hasil pengujian yogurt dengan penambahan 2,5% ini yang paling mendekati dengan kontrol dan memenuhi standar nasional Indonesia (SNI).
Keyword: yogurt, red fruit, probiotic, characteristic physic, characteristic organoleptic

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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