Judul: Physicochemical Characteristics, Antioxidant Activity, and Organoleptical Quality of Greek Yogurt with Addition of Pomegranate Peels Extract
Abstrak: Yoghurt termasuk produk pangan fungsional yang sering dimodifikasi salah satunya dengan penambahan sumber komponen bioaktif alami seperti ekstrak kulit delima (Punica granatum L.). Penelitian bertujuan untuk menganalisis karakteristik fisikokimia, aktivitas antioksidan, dan mutu organoleptik greek yoghurt dengan penambahan ekstrak kulit delima pada taraf berbeda. Greek yoghurt diberi penambahan ekstrak kulit delima sebanyak 0% (kontrol), 0,5%, 1,5%, dan 2,5% dari berat greek yoghurt kontrol. Penelitian dilakukan menggunakan rancangan acak lengkap (RAL) dengan penambahan ekstrak kulit delima sebagai perlakuan. Hasil penelitian menunjukkan bahwa penambahan ekstrak kulit delima pada greek yoghurt berpengaruh nyata (p<0,05) terhadap penurunan pH dan peningkatan aktivitas serta kapasitas antioksidan. Penambahan ekstrak kulit delima meningkatkan kesukaan panelis terhadap atribut rasa namun berlaku sebaliknya pada atribut warna. Makin besar taraf ekstrak kulit delima mengakibatkan kenaikan intensitas warna, aroma, dan rasa ekstrak kulit delima. Sebagai kesimpulan, penambahan 1,5% ekstrak kulit delima dapat memperbaiki karakteristik fisikokimia dan meningkatkan aktivitas antioksidan dengan mutu organoleptik greek yoghurt yang lebih baik., Yogurt is a functional food that is often modified by adding bioactive component such as pomegranate peel extract (Punica granatum L.). This study was aimed to analyze physicochemical characteristics, antioxidant activity, and organoleptical quality of greek yogurt with the addition of pomegranate peels extract at different levels. Greek yogurt was added by pomegranate peels extract at levels of 0% (control), 0,5%, 1,5%, and 2,5% of greek yogurt control's weight. The study was conducted using a completely randomized design (CRD) with the addition of pomegranate peel extract as a treatment. The results showed that pomegranate peels extract added to greek yogurt had significant effects (p<0.05) on decreasing pH and increasing antioxidant activity and capacity. Pomegranate peels extract addiction increased the taste preference but decreased the color preference. Higher level of pomegranate peels extract caused higher intensity of color, aroma, and taste of pomegranate peels extract. In conclusion, the addition of 1,5% pomegranate peels extract improved physicochemical characteristics and increased antioxidant activity with better organoleptic quality of greek yogurt.
Keyword: Antioxidant, Organoleptic, Physicochemical, Pomegranate peels, Yogurt

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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