Judul: Development of Zinc Rich Yogurt Based on Soy Milk (Glycine max L.), Pumpkin Fruit and Seeds (Cucurbita moschata)
Abstrak: Yogurt, susu kedelai dan labu kuning merupakan bahan pangan fungsional yang memiliki komponen biokimia yang baik bagi tubuh. Tujuan penelitian ini adalah untuk mendapatkan formula terbaik dari yogurt berbahan dasar susu kedelai dengan penambahan sari labu kuning dan susu biji labu kuning sebagai pangan tinggi zink dan β-karoten. Penelitian menggunakan Rancangan Acak Lengkap (RAL) dengan rasio sari labu kuning dan susu biji labu kuning yaitu (%) F1 (50:50), F2 (40:60), F3 (30:70). Nilai pH dan viskositas yogurt formula terpilih F3 adalah 3,85 dan 47,5 cP. Hasil organoleptik menunjukkan ketiga formula dapat diterima oleh panelis dan formula yang paling disukai adalah F3 yaitu yogurt susu kedelai dengan penambahan sari labu kuning 30% dan susu biji labu kuning 70%. Hasil analisis kimia yogurt formula terpilih F3 mengandung kadar air 80,61%, abu 1,67%, lemak 4,21%, protein 3,73%, karbohidrat 9,73%, zink 2,5 mg/100mL, dan β-karoten 144,37 µg/100 mL (28,8 RAE). Produk ini memenuhi klaim gizi tinggi zink 2,5 mg/100 mL dan harga jual produk per takaran saji (240 mL) adalah Rp6.700,00., Yogurt, soy milk, and pumpkin are functional food ingredients that have biochemical components that are good for the body. The purpose of this study was to obtain the best formula of soy milk-based yogurt with the addition of pumpkin juice and pumpkin seed milk as a food high in zinc and β-carotene. The study used a completely randomized design with the ratios of pumpkin juice and pumpkin seed milk, namely (%) F1 (50:50), F2 (40:60), and F3 (30:70). The pH value and viscosity of yogurt in the selected formula F3 are 3.85 and 47.5 cP. Organoleptic results showed that the three formulas were acceptable to panelists and the most preferred formula was F3, namely soy milk yogurt with the addition of 30% pumpkin juice and 70% pumpkin seed milk. The results of the chemical analysis of the selected formula F3 yogurt contained 80.61% moisture content, 1.67% ash, 4.21% fat, 3.73% protein, 9.73% carbohydrate, 2.5 mg zinc per 100 mL, and 144.37 µg/100 mL β-carotene (28.8 RAE). This product fulfills the nutrition claim of high zinc content (2.5 mg/100 mL) and the selling price of the product per serving size (240 mL) is IDR 6,700.
Keyword: provitamin A, pumpkin, soy milk, yogurt, zinc

Judul: Antioxidant Activity, Characterization,  and Organoleptic Test of Goat's Milk Yogurt with Addition of Purslane Extract
Abstrak: Yogurt susu kambing merupakan salah satu produk pangan fungsional yang memiliki potensi sebagai sumber antioksidan yang diperlukan oleh tubuh. Pada penelitian ini yogurt susu kambing dimaksimalkan potensinya dengan penambahan ekstrak krokot (Portulaca oleracea) yang berasal dari Banyumas, Jawa Tengah. Penelitian ini bertujuan menentukan formula yogurt susu kambing dan ekstrak krokot yang optimum berdasarkan nilai aktivitas antioksidan tertinggi serta karakteristik yang sesuai dengan SNI. Metode penelitian meliputi ekstraksi, formulasi yogurt, karakterisasi fisik dan kimia, uji organoleptik, dan uji proksimat. Perlakuan terdiri atas F1 (susu kambing tanpa ekstrak krokot), F2 (susu kambing + 2.5% ekstrak krokot), F3 (susu kambing + 5% ekstrak krokot), F4 (susu kambing + 7.5% ekstrak krokot), dan F5 (susu kambing + 10% ekstrak krokot). Hasil penelitian menunjukkan bahwa yogurt formula F2 sebagai yogurt yang paling optimum dengan karakteristik fisik, organoleptik, dan proksimat yang sesuai dengan SNI serta aktivitas antioksidan yang tinggi. Simpulan penelitian ini yaitu F2 merupakan yogurt hasil formulasi dengan karakteristik terbaik., Goat milk yogurt is one of the functional food product that have the potential as a source of antioxidants needed by the body. In this study, the potency of goat's milk yogurt was maximized by the addition of purslane extract (Portulaca oleracea) from Banyumas, Central Java. The aim of this study was to determine the optimum formula for goat's milk yogurt and purslane extract based on the highest antioxidant activity value and characteristics according to SNI. The research steps consisted of extraction, yogurt formulation, physical and chemical characterization, organoleptic test, and proximate test. The treatments consisted of F1 (goat's milk without purslane extract), F2 (goat's milk + 2.5% purslane extract), F3 (goat's milk + 5% purslane extract), F4 (goat's milk + 7.5% purslane extract), and F5 (goat's milk + 10% purslane extract). The results showed that the yogurt formula F2 was the most optimum yogurt with physical, organoleptic, and proximate characteristics in accordance to SNI and the high antioxidant activity. It was concluded that F2 was yogurt with the best characteristics.
Keyword: Antioxidant, DPPH, Formulation, Goat's Milk Yogurt, Portulaca  oleracea

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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