Judul: Kajian Produksi Tanin Bubuk dari Gambir Asalan dengan Pengering Semprot (Spray Dryer)
Abstrak: Gambier extract is a product of gambier plant wich is made from leaf gum and twig gambier plant with certain processing. Main compounds of the gambier extract are pseudotanin catechin and catechutannat acid with the percentage of 7-30% and 22-55%. Catechin and tannin in gambier extract can be purified in order to get products wich have high purity. Some researches were done in the purification of gambier extract related to get pure catechin. However, research for the purification of gambir extract to get pure tannin need to be done. Tannin powder was prepared using drying process with spray dryer. The objectives of this study were to get tannin powder from gambier extract with extraction process and to get the best combination treatment for tannin extraction. This study was done by several factor treatments. They were water temperatures (400C, 600C, dan 800C) and ratio of water and gambier extracts (8:1, 10:1, dan 12:1 v/b). Each treatment in the study used 150 gram gambier extracts. Analysis in this research was done for gambier extract and tannin product. Analysis of gambier extract included proximat analysis and tannin content. Some analysis which were done for tannin product consist of tannin content, moisture content, ash content, color test and insolubility in water content material. The results of analysis which have been done on gambier extract as raw material for tannin powder production have moisture content of 12,36% (wet basis), ash content 12,21% (wet basis), fat content 1,61% (wet basis), rough fiber content 6,16% (wet basis), protein content 3,43% (wet basis), and tannin content 38,45% (wet basis). After extraction process, value of tannin content in tannin product (dry basis) has value from 83% to 98%. Yield of tannin product (dry basis) from purification process has a range value from 16% to 42%. Tannin powder product which were dried by spray dryer has moisture content value (dry basis) between 4% and 6,06%, ash content (dry basis) from 85% to 5,17%, and water insoluble material (dry basis) from 2.99% to 4.43%. Tannin product on color test has hoe degree with average 79.82 which shows yellow color spectrum. Whiteness of tannin product has value between 69.20% and 77.96%. Based on the results, increasing ratio of total water and gambier extract increased yield and tannin content in the product. Generally, increasing temperature of water on tannin extraction increased tannin content in the product. Tannin content and the content of water insoluble material showed the purity level of tannin product. The lower grade of water insoluble material showed smaller value of non tannin material and showed product with better purity. Drying process which used spray dryer could produce tannin powder with uniform grain size. Stability of temperature in drying process could give effects to the preparation of tannin powder like mousiture content and whiteness value. Based on the analysis of variance at α = 0.05, factor of total water and gambier extract ratio did not affect significantly to the value of tannin content, 6 moisture content, ash content, whiteness, and water insoluble material content but it gave significantly effects for the yield value
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Judul: Kajian Pembuatan Gambir Bubuk Dari Daun Gambir (Uncaria Gambir Roxb.) Kering Menggunakan Spray Dryer
Abstrak: Gambier is the sap of dried leaves and twigs extracts of gambier plant (Uncaria gambir Roxb.) The main chemical components contained in gambier are catechin and tannin. Both of these chemical compounds contribute to the usefulness and high added value. Indonesia is the highest producer and exporter of gambier in the world. Indonesian gambier export has some problems caused by low and different quality of gambier. On the other hand, extraction that has been done by local people did not support to produce high quality of gambier. Delay in fresh leaf gambier extraction can cause the decreasing of gambier quality. The further study of gambier extraction must be done to find the right method to produce high quality of gambier. Drying leaves is one method to keep the quality of gambier. This study aims to determine the influence of type and concentration solvent for the yield, catechin content, and the quality of gambier powder that are extracted by organic solvents from dried gambier leaves, and to measure the effect of difference shelf-life in the quality of gambier powder. The extraction of dried gambier leaves had been done by some stages, that were reduction gambier leaves size using Hammer Mill, solvent extraction in Shaker Waterbath at 500C for 90 minutes, maceration for 3 x 24 hours, filtering, and drying using Spray Dryer. Type of solvent used were ethanol, methanol, and isopropanol at concentration 100%, 75%, and 50%. The effect of difference shelf-life had been done by using ethanol 96% at initial week, first week, second week, third week, and fourth week. Based on calculations on yield gambier, it were obtain that ethanol at a concentration of 75% gave the highest yield gambier (13,43%). Type of solvent significantly affected the yield of gambier, whereas the concentration in each solvent did not affect significantly to the yield of gambier. Analysis of catechin content in the product showed that the highest levels of catechin was obtained in the solvent isopropanol 100% (93.47% db), and the lowest of catechin content in the solvent was ethanol 50% (24,36% db). Solvent type and concentration of each solvent gave a significant effect on the concentration of catechin in gambier powder. The extraction used ethanol, methanol, dan isopropanol at concentration 100% gave the first quality of gambier. The extraction used isopropanol 75% gave the second quality of gambier. Whereas, the extraction used etanol and methanol at 75% and 50%, and also isopropanol at 50% is not qualified. Quality analysis of gambier powder showed that the product had water content from 3,47% to 6,23%, ash content was from 0,54% db to 4,66% db, insoluble material in water content was from 13,04% db to 37,93% db, insoluble material in alcohol content was from 3,96% db to 11,96% db, and had brownish yellow color to greenish brown color. Water content, ash content, insoluble material in alcohol content, and color of gambier powder had qualified as the first quality of gambier, whereas the content of insoluble material in water was not qualified.
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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