Judul: Analisis kapasitas antioksidan dan kandungan total fenol pada sayuran
Abstrak: Sampai saat ini penelitian mengenai analisis kapasitas antioksidan dari berbagai jenis sayuran Indonesia masih terbatas. Tujuan penelitian ini adalah menganalisis kapasitas antioksidan dan kandungan total fenol dari berbagai jenis sayuran Indonesia. Penentuan 21 jenis sayur dan lokasi pembelian sayur (pasar Anyar, Bogor) dilakukan dengan metode purposive. Kapasitas antioksidan dianalisis dengan metode 1.1-diphenyl-2- picrylhydrazyl (DPPH) dan kandungan total fenolnya dengan Folin- Ciocalteu basis basah. Kapasitas antioksidan terbesar terdapat pada pohpohan yaitu 35.91±0.21 mg AEAC/100 g atau 3043.62±0.12 mg/100 g, dan terkecil pada labu siam yaitu 0.30 mg±0.09 AEAC/100 g atau 5.01±0.02 mg/100 g. Sayuran daun berwarna hijau dan merah memiliki kapasitas antioksidan lebih besar dibanding sayuran bunga, buah, umbi dan kacang. Kandungan total fenol tertinggi terdapat pada selada 190.74±0.80 mg TAE/100 g dan terendah pada labu siam 6.63±0.75 mg TAE/100 g. Terdapat hubungan yang positif antara kapasitas antioksidan dan kandungan total fenol (p<0.01, r=0.661) pada sayuran., Limited studies analyzed antioxidant capacity of vegetables of Indonesia. The aim of this study was to analyze antioxidant capacity and total phenolic content of vegetables of Indonesia. Purposive sampling was applied to determine 21 types of vegetables and purchasing location (Anyar traditional market of Bogor). The antioxidant capacity was determined using 1.1-diphenyl-2-picrylhydrazyl (DPPH) method, while total phenolic content were determined using Folin-Ciocalteu method on fresh weigh basis. The highest antioxidant capacity was found in pohpohan 35.91±0.21 mg AEAC/100 g or 3043.62±0.12 mg/100 g, while the lowest was in chayote 0.30 mg±0.09 AEAC/100 g or 5.01±0.02 mg/100 g. Green and red leavy vegetables have higher antioxidant capacity than others. The highest total phenolic content was found in lettuce 190.74±0.80 mg TAE/100 g and the lowest was in chayote 6.63±0.75 mg TAE/100 g. There is possitive correlation between antioxidant capacity and total phenolic content in these vegetables (p<0.01, r=0.661). Keywords: antioxidant, DPPH,
Keyword: antioksidan, DPPH, total fenol, sayuran

Judul: Analisis kapasitas Antioksidan dan kandungan total Fenol pada buah
Abstrak: Buah merupakan salah satu potensi sumber antioksidan. Penelitian mengenai kapasitas antioksidan dan kandungan total fenol buah dari Indonesia masih sangat terbatas. Tujuan dari penelitian ini adalah untuk menganalisis kapasitas antioksidan dan kandungan total fenol dari berbagai jenis buah yang diperjualbelikan dan dikonsumsi di Indonesia. Tiga puluh jenis buah dipilih secara purposif di pasar Anyar, Bogor. Kapasitas antioksidan buah dianalisis menggunakan metode DPPH dan total fenol dianalisis menggunakan metode Folin-Ciocalteau. Hasil menunjukkan bahwa asam jawa memiliki kapasitas antioksidan tertinggi dengan 76.15±0.09 mg AEAC/100 g. Pisang mas memiliki kapasitas antioksidan terendah dengan 1.29±0.14 mg AEAC/100 g. Buah berwarna tua memiliki rata-rata kapasitas antioksidan lebih tinggi dibandingkan dengan buah berwarna muda. Markisa memiliki kandungan total fenol tertinggi dengan 3.25±1.70 mg TAE/100 g, dan pisang kepok terendah dengan 0.12±0.29 mg TAE/100 g. Penelitian ini juga menunjukkan adanya korelasi positif antara kapasitas antioksidan dan kandungan total fenol (p<0.05; r=0.545, Fruit is one of potential sources of antioxidant. Very limited studies have been done in determining the antioxidant capacity and phenolic content of fruits of Indonesia. The objective of this study was to analyze the antioxidant capacity and phenolic content of various types of fruits is traded and consumed in Indonesia. Thirty kind of fruits were selected purposively in Anyar traditional market of Bogor. The antioxidant capacity of the fruits was evaluated by applying DPPH method and total phenolic content was analized by applying the Folin- Ciocalteau method. The results showed that tamarind has the highest antioxidant capacity of 76.15±0.09 mg AEAC/100 g Mas banana is the lowest antioxidant capacity of 1.29±0.14 mg AEAC/100 g. Dark-colored fruits have a higher antioxidant capacity than the light-colored fruit. Passion fruit has the highest total phenolic content of 3.25±1.70 mg TAE/100 g and kepok banana has the lowest total phenolic content of 0.12±0.29 mg TAE/100 g. This study also showed that the positive correlation between antioxidant capacity and total phenolic content (p<0.05; r=0.545).
Keyword: antioksidan, buah, total fenol

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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