Judul: Physicochemical Properties and Organoleptic Test of Yogurt with The Addition of Red Dragon Fruit Juice (Hylocereus polyrhizus) as an Antioxidant
Abstrak: Yogurt merupakan produk susu dan memiliki rasa asam untuk meningkatkan rasa asam ditambahkan perisa alami yaitu sari buah naga merah . Buah naga merah merupakan buah yabg mengandung antioksidan. Penelitian ini bertujuan untuk memanfaatkan yogurt dengan penambahan sari buah naga merah sebagai antioksidan alami dan mengetahui sifat fisikokimia yogurt yang dihasilkan dari penambahan berbagai kadar sari buah naga merah meliputi ph, aw, viskositas dan titrasi total asam. Hasil yang diperoleh diharapkan dapat dijadikan acuan dalam pembuatan yogurt buah naga merah yang memiliki sifat fisikokimia sesuai dengan yang diharapkan. Rancangan yang digunakan dalam analisis data penelitian ini adalah Rancangan Acak Lengkap (RAL) yang kemudian juga dilakukan pengujian Tukey Test. DataOrganoleptik diuji menggunakan uji statistik non parametrik Kruskal-Wallis. Hasil yang diperoleh diharapkan dapat dijadikan acuan dalam pembuatan yogurt buah naga merah yang memiliki sifat fisikokimia sesuai dengan yang diharapkan., Yogurt is a dairy product and has a sour taste to increase the sour taste, natural flavor is added, namely red dragon fruit juice. Red dragon fruit (Hylocereus polyrhizus) is a fruit that contains antioxidants. This study aims to utilize yogurt with the addition of red dragon fruit juice as a natural antioxidant and determine the physicochemical properties of yogurt produced from the addition of various levels of red dragon fruit juice including ph, aw, viscosity and total acid titration. The results obtained are expected to be used as a reference in making red dragon fruit yogurt that has physicochemical properties as expected. The design used in the analysis of this research data is a completely randomized design (CRD) which is then also tested by Tukey Test. Organoleptic data was tested using the Kruskal-Wallis non-parametric statistical test. The results obtained are expected to be used as a reference in making red dragon fruit yogurt that has physicochemical properties as expected.
Keyword: antioxidant, hylocereus polyrhizus, milk, yogurt

Judul: Physical and Organoleptical Properties of Goat Milk Probiotic Yogurt with Addition of Red Fruit (Pandanus conoideus)
Abstrak: Yogurt susu kambing merupakan jenis minuman yang berasal dari susu kambing etawah yang memiliki ciri rasa asam, dan segar dari proses fermentasi. Buah merah merupakan tumbuhan endemik Papua. Buah merah membantu penyembuhan penyakit, termasuk kanker dan HIV/AIDS. Penelitian ini bertujuan menganalisis sifat fisik dan organoleptik yogurt susu kambing dengan penambahan ekstrak buah merah. Taraf pemberian ekstrak buah merah tersebut adalah 0% (P0), 2,5% (P1) dan 5% (P3). Penelitian ini menggunakan rancangan acak lengkap (RAL) dengan tiga kali pengulangan. Pengujian sifat fisik adalah nilai pH, nilai aw, viskositas dan total asam tertitrasi (TAT). Pengujian sifat organoleptik yang dianalisis adalah flavour, warna, aroma, dan tekstur. Data sifat fisik dianalisis dengan ANOVA satu faktor dan diuji lanjut dengan uji Duncan, hasil menunjukkan bahwa perbedaan penambahan ekstrak buah merah pada yogurt berpengaruh nyata (P<0,05) pada pH. Data sifat organoleptik dianalisis dengan uji non parametrik Kriskal-wallis dan diuji lanjut dengan Mann Whitney hasil hedonik menunjukkan berpengaruh nyata (P<0,05) pada parameter warna, sedangkan pada mutu hedonik berpengaruh sangat nyata (P<0,01) pada warna, aroma, flavor, dan kekentalan., Goat milk yogurt is a type of drink derived from goat's milk etawah which has a sour taste, and fresh from the fermentation process. Red fruit is a plant endemic Papua. Red fruit helps cure diseases, including cancer and HIV / AIDS. The research was aimed to analyze the physical and organoleptical properties of goat's milk yogurt with the addition of red fruit extract. Those levels consisted the control 0% (P0), 2,5%(P1), and 5%(P2) of red fruit extract. The research used completely randomized design (CRD) with three replications. The observed variables of physical properties were pH, aw, viscosity and total acid titrated (TAT). The observed organoleptic properties were flavor, color, aroma, and texture. Physical data were analyzed by one-factor ANOVA and further tested by Duncan test, the results showed that the difference in the addition of red fruit extract to yogurt had a significant effect (P <0,05) on pH. Organoleptic properties data were analyzed by non-parametric Kruskal-wallis test and further tested with Mann Whitney, the hedonic results showed a significant effect (P<0,05) on color parameters, while the hedonic quality had a very significant effect (P<0,01) on color, aroma, flavor and viscosity.
Keyword: buah merah, fisik, organoleptik, yogurt susu kambing

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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