Judul: Sifat Fisikokimia, Organoleptik dan Aktivitas Antioksidan Dim Sum Daging Ayam dengan Bahan Pengisi Tepung Ubi Jalar Ungu
Abstrak: Dim sum daging ayam dengan bahan pengisi tepung ubi jalar ungu berpotensi sebagai pangan fungsional dengan inovasi terbaru. Tepung ubi jalar ungu memiliki kandungan antosianin yang berfungsi sebagai antioksidan dan penangkap radikal bebas sehingga dapat mencegah kanker, penyakit degenerarif dan penuaan. Penelitian ini bertujuan untuk menguji sifat fisikokimia, organoleptik serta aktivitas antioksidan dim sum daging ayam dengan bahan pengisi tepung ubi jalar ungu. Tepung ubi jalar ungu yang ditambahkan pada adonan dim sum merupakan pengganti penggunaan tepung sagu dengan persentase substitusi 0%, 50%, dan 100%. Hasil penelitian menunjukkan bahwa penelitian berpengaruh nyata (p<0,05) terhadap peningkatan nilai kapasitas antioksidan, aktivitas penghambatan DPPH dan karakteristik organoleptik uji mutu hedonik pada atribut warna. Secara keseluruhan dim sum daging ayam dengan bahan pengisi tepung ubi jalar ungu sebesar 100% menunjukkan hasil terbaik untuk pengujian sifat fisikokimia, organoleptik dan aktivitas antioksidan., Chicken dim sum with the addition of purple sweet potato flour has potential as a functional food with the newest innovation. Purple sweet potato flour contains anthocyanins that function as antioxidants and free radical scavengers, so it can prevent cancer, degenerative diseases, and aging. The purpose of this research to determine the physicochemical, sensory properties and antioxidant activity of chicken dim sum with the addition of purple sweet potato. The purple sweet potato flour added to the dim sum dough is a substitute for the use of sago flour with a substitution percentage of 0%, 50% and 100%. The results showed that the research had a significant effect (p<0.05) on the value of antioxidant capacity, DPPH inhibitory activity and organoleptic characteristics of hedonic quality tests on color attributes. Overall chicken dim sum with purple sweet potato flour as a filler of 100% showed the best results for testing physicochemical properties, sensory properties and antioxidant activity
Keyword: antioxidant activity, meat chicken dim sum, purple sweet potato four, physicochemical properties, sensory properties

Judul: Sifat Fisikokimia, Organoleptik dan Aktivitas Antioksidan Dendeng Daging Ayam dengan Penambahan Serbuk Bunga Rosella
Abstrak: Dendeng berpotensi mengalami reaksi oksidasi yang dapat dihambat dengan antioksidan. Senyawa antioksidan banyak terkandung dalam bahan alami, seperti bunga rosella. Penelitian ini bertujuan untuk menguji sifat fisikokimia, organoleptik dan aktivitas antioksidan dendeng daging ayam dengan penambahan serbuk bunga rosella. Variabel yang diukur dalam penelitian ini meliputi nilai pH, aw, kadar air, aktivitas penghambatan terhadap 2,2-difenil-1-pikrilhidrazil (DPPH), kapasitas antioksidan, nilai TBARS, dan sifat organoleptik (warna, aroma, tekstur, dan rasa) dendeng daging ayam. Rancangan yang digunakan dalam penelitian ini adalah rancangan acak lengkap (RAL) dengan tingkat penambahan serbuk bunga rosella yang berbeda (0%; 0,15%; 0,30%). Hasil penelitian menunjukkan bahwa penambahan serbuk bunga rosella berpengaruh nyata (p<0,05) terhadap nilai pH yang semakin menurun, serta nilai aw dan kadar air yang semakin meningkat. Penambahan serbuk bunga rosella tidak berpengaruh nyata terhadap nilai TBARS, aktivitas penghambatan DPPH dan kapasitas antioksidan. Secara keseluruhan dendeng daging ayam dengan penambahan serbuk bunga rosella pada taraf 0,15% dan 0,30% tidak memberikan pengaruh terhadap sifat fisikokimia, organoleptik, dan aktivitas antioksidan., Jerky has the potential to undergo oxidation reactions that can be inhibited by antioxidants. Many antioxidant compounds are contained in natural ingredients, such as rosella flowers. This study aimed to examine the physicochemical, organoleptic, and antioxidant activity of chicken meat jerky with the addition of roselle flower powder. The variables measured in this study included pH value, aw, moisture content, inhibition of 2,2-diphenyl-1-picrylhydrazyl (DPPH), antioxidant capacity, TBARS value, and organoleptic properties (color, aroma, texture, and taste) of chicken meat. The jerky design used in this study was a completely randomized design (CRD) with different levels of rosella flower powder addition (0%; 0.15%; 0.30%). The results showed that the addition of rosella flower powder had a significant effect (p<0.05) on the decreasing pH value and increasing water content. The addition of rosella flower powder did not significantly affect the TBARS value, DPPH inhibitory activity and antioxidant capacity. Overall chicken jerky with the addition of rosella flower powder at the level of 0.15% and 0.30% did not affect the physicochemical, organoleptic, and antioxidant activity properties.
Keyword: antioxsidant, meat chicken jerky, physicochemical sensory, rosella flowers, sensory 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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