Judul: Oil Palm Exocarp and Empty Fruit Bunches Based Material for Food Preservatives and Hazardous Ingredients Detector
Abstrak: Penelitian menggunakan kulit buah sawit (EBS) belum banyak dilakukan dibandingkan dengan tandan kosong kelapa sawit (TKKS). Penelitian ini dilakukan untuk mengekstraksi kandungan senyawa antosianin yang terdapat pada EBS dan mempergunakan nanoselulosa tersebut sebagai pendeteksi bahan berbahaya dan pengawet yang umumnya ditemukan dalam produk makanan (BPMB). Antosianin dari EBS diekstraksi menggunakan pelarut Metanol 96%-HCl 1%, sedangkan isolasi selulosa menggunakan metode Alkali Hidrogen Peroksida-Asam Perasetat. Selulosa dikonversi menjadi selulosa nanokristal (CNC) melalui metode hidrolisis asam sulfat dengan bantuan gelombang ultrasonikasi. Uji deteksi kandungan BPMB menggunakan formalin, boraks, dan sodium nitrit yang di variasikan dari konsentrasi 10-100.000 ppm. Hasil penelitian menunjukkan rendemen isolasi CNC diperoleh sebanyak 12,31%. Terjadi perubahan morfologi, peningkatan derajat kristalinitas, sifat termal, dan gugus fungsi akibat perubahan komponen kimia dalam serat TKKS. Deteksi terbaik ditunjukkan pada bahan sodium nitrit 10 ppm, boraks 500 ppm, dan formalin 500 ppm. Sementara itu, penambahan CNC mampu meningkatkan efektivitas deteksi bahan pengawet berbahaya kecuali pada boraks., Research on using the palm fruit exocarp (PFE) has yet to be carried out to a greater extent than the empty palm fruit bunches (EFB). In this research, anthocyanin of the PFE was used along with the EFB nanocellulose as a detector for preservatives and hazardous substances commonly found in food products (FPHS). Anthocyanins were extracted from PFE waste using a 96% HCl - 1% methanol solution, and cellulose was isolated from EFB using the alkali hydrogen peroxide-peracetic acid. The extracted cellulose was then converted into nanocrystalline cellulose (CNC) by ultrasonic assisted-hydrolysis. The FPHS used for detection sensitivity was formalin, borax, and sodium nitrite at concentrations varied from 10-100,000 ppm. The results showed that the isolation yield of CNC was 12.31%. The morphology of the cellulose and CNC were changed. Changes in functional groups and increased crystallinity and thermal properties were also found. Anthocyanin and CNC systems effectively detected the 10 ppm sodium nitrite, 500 ppm borax, and 500 ppm formalin. Meanwhile, CNC addition increased the detection sensitivity, except for borax.
Keyword: anthocyanin, food preservative, nanocellulose, oil palm

Judul: Uji aktivitas antioksidan lignin dari tandan kosong kelapa sawit
Abstrak: The increasing oil palm plantation will increase the amount of oil palm production. One of the solid waste from oil palm industry is empty fruit bunch (EFB) that contain lignocellulose. This research used lignin content in EFB as an antioxidant. Lignin delignification from EFB was done by pulping organosolv method using ethanol. Lignin antioxidant activity was characterized with DPPH method (1,1-diphenyl-2-picrylhydrazyl) as free radical, measured as IC50 (inhibition concentration 50%). Lignin yield was 9,09%; lignin content 76,57%; and fourier transform infrared (FTIR) spectrum indicated the lignin. Phenolic hydroxyl and molecular weight lignin were also determine the lignin antioxidant activity. This result pointed out that the lignin have phenolic structure of type 2 and 3 each 0,4% and the molecular weight is 4005 g/mol. Butylated hydroxytoluene (BHT), a commercially chemical antioxidant, was used as a positive control. The IC50 of lignin is 50,2 ppm, while IC50 that of BHT is 1883 ppm. This result shows that antioxidant activity of lignin is higher than that of BHT.
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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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