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: Kajian Pemanfaatan dan Pengembangan Potensi Ekstrak Manggis Merah (Garcinia forbesii) sebagai Minuman Fungsional Kaya Antioksidan dan Kestabilannya
Abstrak: Red Mangosteen (Garcinia forbesii) is a fruit that comes from South Kalimantan and rarely used by people. Red mangosteen fruit has white flesh with sweet flavor and fresh red rind with strong sour taste. Red mangosteen rind has a potency to be processed into functional beverage. This study is aimed to determine the functional beverage formulas made from red mangosteen rind extract (M) and emprit ginger extract (J) with the addition of pekak extract (P) and cinnamon extract (K) and then analyzed the characterization of physicochemical properties, functional and determination of its stability at high temperatures. Raw Material M obtained in the form of extracts with 1.4 TPT oBrix while J , P and K obtained by water extraction with water and spices ratio of 1:10 for J and 1:5 for P and K. Formula drink based on M and J was made in three concentration ratio, which is 5:1 (MJ 1), 5:2 (MJ 2), and 5:3 (MJ 3) (v/v). MJ 1 formula is selected as the basic formula based on hedonic rating test and antioxidant capacity. MJ 1 formula is given each addition P extracts and K extract which is made in three different concentrations, are 5%, 10%, and 15%. Formula MJP 5% and MJK 5% is chosen as the selected formula to determine its stability. Formula MJP 5% has the antioxidant capacity 6,46 mg AEAC/mL and total phenol content 20,38 mg GAE/mL, while MJP 5% has 7,95 mg AEAC/mL antioxidant capacity and total phenol content 21,17 mg GAE/mL. Determination of stability MJP 5% and MJK 5% to 85% usable quality was conducted by using the Arrhenius method with antioxidant capacity and total phenol content as parameters. Both formulas packaged in vials dark bottles of 10 ml volume without heating treatment processes, such as pasteurization and sterilization and stored in an incubator at temperature 35°C, 45°C and 55°C. Stability of MJK 5% stored at 35°C, 45°C and 55°C are 8 days, 5 days and 4 days based on the antioxidant capacity parameter and 7 days, 6 days, and 5 days based on total phenol parameters, while the stability of MJP 5% is 9 days, 6 days, and 5 days based on antioxidant capacity parameter and 7 days, 6 days, and 5 days based on total phenol parameter. The observation results showed that the formula mixture of red mangosteen rind extract and ginger extract by the addition of pekak extract and cinnamon extract could potentially be developed as a functional drink from the utilization of rare fruit cultivation, red mangosteen fruit.
Keyword: Arrhenius, cinnamon, pekak, emprit ginger, red mangosteen rind, functional drink

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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