Judul: Optimasi Fermentasi Justicia gendarussa Burm.f. oleh Aspergillus oryzae Berdasarkan Respon Kapasitas Antioksidan, Total Fenolik dan Flavonoid
Abstrak: Gandarusa mempunyai aktivitas antioksidan yang diduga berasal dari senyawa flavonoid dan fenolik. Faktor-faktor yang mempengaruhi hasil fermentasi padat oleh Aspergillus oryzae belum diketahui, sehingga diperlukan penelitian mengenai optimasi fermentasi untuk memaksimalkan potensi tersebut. Proses fermentasi diberi perlakuan seperti suhu, waktu, konsentrasi inokulum, dan kelembaban. Faktor suhu dan kelembaban mempengaruhi proses selama pertumbuhan jamur pada media, parameter tersebut tidak lepas dari parameter waktu fermentasi. Semakin lama waktu fermentasi maka kandungan total fenolik dan kapasitas antioksidannya semakin tinggi. Fermentasi tanaman gandarusa dengan Aspergillus oryzae mengalami peningkatan nilai kandungan total fenolik dan flavonoid, kapasitas antioksidan metode DPPH dan FRAP dibandingkan dengan tanaman gandarusa yang tidak difermentasi. Rancangan fermentasi optimal yang diperoleh adalah, waktu fermentasi 14 hari, suhu fermentasi 45°C, kelembaban 20% total kadar air, dan konsentrasi inokulum 20%., Gandarusa has antioxidant activity that is believed to come from flavonoid and phenolic compounds. Factors influencing solid-state fermentation outcomes by Aspergillus oryzae are not yet known, so research is needed to optimize fermentation to maximize this potential. The fermentation process involves variables such as temperature, time, inoculum concentration, and humidity. Temperature and humidity factors affect the process during fungal growth in the media, and these parameters are closely linked to fermentation time. The longer the fermentation time, the higher the total phenolic content and antioxidant capacity. Fermentation of Gandarusa plants with Aspergillus oryzae leads to increased total phenolic and flavonoid content, as well as antioxidant capacity using DPPH and FRAP methods compared to non-fermented Gandarusa plants. The optimal fermentation design obtained includes a fermentation time of 14 days, fermentation temperature of 45°C, humidity of 20% total moisture content, and inoculum concentration of 20%.
Keyword: antioxidant, Aspergillus oryzae, Justicia gendarusssa, phenolic, solidstate fermentation

Judul: Design of Gendarussa Fermentation by  Aspergillus tamarii with Response on Antioxidant Capacity, Total Flavonoids and  Phenolics
Abstrak: Tanaman obat di Indonesia sangat berlimpah sehingga berpotensi dijadikan bahan baku obat, salah satunya gandarusa (Justicia gendarussa Burm F.). Gandarusa merupakan tanaman obat yang termasuk ke dalam kelompok tanaman perdu yang memiliki potensi sebagai antioksidan. Potensi tersebut disebabkan adanya senyawa metabolit sekunder seperti fenolik dan flavonoid. Aspergillus tamarii adalah fungi yang berfilamen sehingga dipercaya mampu meningkatkan senyawa metabolit sekunder melalui proses fermentasi media padat. Tujuan penelitian ini untuk mendapatkan desain formula fermentasi pada gandarusa oleh A.tamarii dengan respon kapasitas antioksidan, kadar total fenolik (TPC) dan flavonoid (TFC). Desain fermentasi dilakukan dengan menggunakan software Design Expert metode two half level factorial. Hasil penelitian menunjukkan faktor fermentasi yang berpengaruh terhadap TPC, TFC, kapasitas antioksidan 2,2- diphenyl-1-picrylhydrazyl (DPPH) dan ferric reducing antioxidant power (FRAP) adalah waktu, suhu, dan konsentrasi inokulum. Solusi desain fermentasi gandarusa yang didapat waktu fermentasi 14 hari, suhu fermentasi 45 ˚C, kelembaban 2 mL, dan konsentrasi inokulum 100%., The medicinal plants in Indonesia are abundant and have the potential to be used as raw materials for medicine production, one of which is gendarusa (Justicia gendarussa Burm F.). Gendarusa is a medicinal plant that belongs to the group of perennial plants and has the potential to be an antioxidant. This potential is due to the presence of secondary metabolites such as phenolics and flavonoids. Aspergillus tamarii is a filamentous fungus believed to be capable of increasing secondary metabolite compounds through solid-state fermentation. This research aimed to obtain a fermentation formula design for gendarusa by A.tamarii with response variables of antioxidant capacity, total phenolic content (TPC), and total flavonoid content (TFC). The fermentation design was conducted using the Design Expert software with a two-half-level factorial method. The research results showed that the fermentation factors affecting TPC, TFC, 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant capacity, and ferric-reducing antioxidant power (FRAP) are time, temperature, and inoculum concentration. The fermentation design solution for gendarusa obtained a fermentation time of 14 days, a fermentation temperature of 45 ˚C, a moisture content of 2 mL, and an inoculum concentration of 100%.
Keyword: antioksidan, Aspergillus tamarii, Design Expert, fermentasi media padat, gandarusa

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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