Judul: Polyphenol Extraction from Mangosteen Pericarp (Garcinia mangostana L.) and Its Application in Tea Product
Abstrak: Mangosteen pericarp has high polyphenol content that have disease preventive properties. The objective of this research was to utilize mangosteen pericarp from waste into added value and to evaluate stability on polyphenol content of green tea drink with mangosteen pericarp extract. Mangosteen pericarp was dried at 50ºC using tray dryer and the moisture content reached 7.43±0.10%. Dried pericarp was extracted with distilled water at 1:5 ratio (w/v). Green tea drink was added by mangosteen pericarp extract with seven different concentrations (0.1-0.7%). The extract then was infused into green tea drink which was mixed with three different concentrations of citric acid (0.06, 0.1, and 0.2%). The result showed that mangosteen pericarp extract had total phenolic compound (127.39±1.19 mg GAE/ml sample), DPPH (4491.63±67.52 μmol Trolox/ml sample), and FRAP (21,492±134.50 mM asorbic acid/ml sample). The maximum concentration of mangosteen pericarp extract in the tea drink that can be accepted by panelist was 0.4%. Tea with the highest concentration of citric acid (0.2%) had the lowest pH (2.79), the highest total phenolic compound (25.48±0.38 mg GAE/ml sample), DPPH (57862.08±1248.85 μmol Trolox/100 ml sample), and FRAP (5,681.11±33.39 mM asorbic acid/ml sample) compared with other treatments (p<0.05). Therefore, the study concluded that mangosteen pericarp extract can be applied in tea drink and provided more polyphenol content for the product. In addition, polyphenol was more stable in acid condition.
Keyword: Polyphenol, Antioxidant capacity, Mangosteen pericarp, Tea, Citric acid.

Judul: Karakter Kulit Manggis, Kadar Polifenol Dan Potensi Antioksidan Kulit Manggis (Garcinia mangostana L.) Pada Berbagai Umur Buah Dan Setelah Buah Dipanen
Abstrak: The objective of this study were to know the character of mangosteen rind during development of the mangosteen fruit, studying the total phenol content and antioxidant potential of mangosteen rind. Research was done at Plant Analysis and Chromatoghrapy Laboratory, Deparment of Agronomy and Horticulture, Bogor Agricultural University. This research used Completely Randomized Desain Group (RKLT) single factor wich is harvesting, with continue test Duncan Multiple Range Test (DMRT) at level 5%. Harvesting one month after anthesis (BSA), 2 BSA, 3 BSA, 4 BSA and the rind storage two and four weeks after harvesting were done separately. Mangosteen fruit was harvested from Leuwiliang, Bogor. The result showed that total phenolic at crude extract mangosteen and antioxidant capacity to reach IC50 of harvesting and storage have negative correlation. Harvesting handling have effect to fruit weight, aril weight, wet weight rind and vitamin C content. Total phenolic of Harvesting and storage handling have a negative correlation with antioxidant capacity to reach IC50 which are value about -0.53 and -0.91. Assumed that total phenolic content will increase antioxidant capacity in mangosteen rind. Antioxidants capacity on harvesting and sorage handling of mangosteen have IC50<50 (capability of antioxidant are very strong).
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Judul: Formulasi Hamiltonian untuk Menggambarkan Gerak Gelombang Soliter Dimensi Tiga di Permukaan Laut
Abstrak: Gelombang permukaan adalah gelombang yang terjadi perbedaan rapat massa antara air dan udara. Salah satu gelombang permukaan yang ditinjau adalah gelombang soliter. Formulasi gelombang soliter dilakukan dengan menggunakan formulasi Hamiltonian.
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