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: Perubahan Komponen Kimia Fungsional Umbi, Tepung, dan Beras Analog Ubi Jalar Ungu
Abstrak: Ubi jalar ungu dapat dikembangkan menjadi produk pangan fungsional seperti beras analog. Penilitian ini bertujuan untuk mengevaluasi komponen kimia fungsional dan aktivitas antioksidan selama pengolahan umbi menjadi tepung dan beras analog ubi jalar ungu. Hasil penelitian pada umbi diperoleh: kadar air 78,00% basis basah (bb), kadar abu 9,70% basis kering (bk), kadar lemak 5,47% (bk), kadar protein 26,93% (bk), kadar karbohidrat 58,41% (bk), kadar antosianin 31,79 mg/100 g (bk), kadar β-karoten 1,77 mg/100 g (bk), dan aktivitas antioksidan 65,70%. Hasil penelitian pada tepung ubi diperoleh: kadar air 6,71% (bb), kadar abu 2,40% (bk), kadar lemak 1,06% (bk), kadar protein 3,80% (bk), kadar karbohidrat 92,75% (bk), kadar antosianin 3,47 mg/100 g (bk), kadar β-karoten 0,15 mg/100 g (bk), dan aktivitas antioksidan 45,59%. Hasil penelitian pada beras analog ubi diperoleh: kadar air 8,43% (bb), kadar abu 1,78% (bk), kadar lemak 1,62% (bk), kadar protein 4,13% (bk), kadar karbohidrat 92,50% (bk), kadar antosianin 0,71 mg/100 g (bk), kadar β-karoten 0,11 mg/100 g (bk), dan aktivitas antioksidan 8,38%. Analisis statistik menunjukkan bahwa proses pengolahan umbi menjadi tepung serta tepung menjadi beras analog menyebabkan perbedaan yang nyata pada parameter yang diamati., Purple sweet potato can be developed into functional food products like analog rice. This study aims to evaluate the functional chemical components and antioxidant activity during the processing of purple sweet potato into flour and purple sweet potato analog rice. The results of research on sweet potato obtained: water content 78,00% wet basis (wb), ash content 9,70% dry basis (db), fat content 5,47% (db), protein content 26,93% (db), carbohydrate content 58,41% (db), anthocyanin content 31,79 mg/100 g (db), β-carotene content 17,73 mg/100 g (db), and antioxidant activity 65,70%. The results of research on sweet potato flour obtained: water content 6,71% (wb), ash content 2,40% (db), fat content 1,06% (db), protein content 3,80% (db), carbohydrate content 92,75% (db), anthocyanin content 3,47 mg/100 g (db), β-carotene levels 1,51 mg/100 g (db), and antioxidant activity 45,59%. The results of the research on sweet potato analog rice obtained: water content 8,43% (wb), ash content 1,78% (db), fat content 1,62% (db), protein content 4,13% (db), carbohydrate content 92,50% (db), anthocyanin content 0,71 mg/100 g (db), β-carotene content 1,05 mg/100 g (db), and antioxidant activity 8,38%. Statistic analysis shows that the processing of purple sweet potato into flour and flour into analog rice causes a significant difference in the observed parameters.
Keyword: antioxidant, anthocyanin, beta carotene, carbohydrate, food processing

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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