#TITLE_ALTERNATIVE#

• Main Author: SEPTIANI MANGIWA ( NIM : 20510027); Pembimbing : Prof. Dr. Buchari
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/17200
• Institution: Institut Teknologi Bandung

Coffee is a beverage derived from coffee processing plant seeds and is believed to be beneficial for human body because they contain various chemical components. In general, coffee contains the active chemical compound in the form of alkaloids, saponins, flavonoid and polyphenol. Caffeine is one of the active chemical classes of alkaloids contained in it. Coffee beans also contain chlorogenic acid, which is one class of polyphenolic compounds that act as antioxidants. Caffeine and chlorogenic acid present in coffee beans in considerable amounts, especially in green coffee beans. Today, the study of green coffee beans and the content of chemical compounds contained in it to the attention of many researchers, particularly for purposes of quality control analysis. To the quality control analysis, we need a standard reference material as appropriate. However, standard reference material tend to be expensive and difficult to obtain. Therefore, in this research studied the preparation of candidate reference material for the determination of caffeine and chlorogenic acid in green coffee beans. The samples used came from green coffee beans Arabica species that was obtained from the Pangharapan Village, District of Pangalengan, Bandung regency of West Java. Coffee beans are separated based on the level of maturity, the raw coffee beans, medium-ripe and ripe. As a general character, specified moisture content, ash content, metals (Fe, Cu and Zn) content and spectroscopy absorption irradiation red (IR) analysis. Preparation green coffe beans as candidate reference material to exist are separation of beans and skin, fermentation, washing, drying, softing and well kept. Fermentation by wet fermentation method. Moisture content specified with heated 1 gram of sample using oven at 105oC while 2 hours. Ash content specified by burning 1 gram of sample in the furnace at 750oC while 4 hours. Metals content specified by atomic absorption spectrofotometry (AAS). From result of this research, moistrure content approximately was 5,61% -8,17%, ash content was 2,76 % -5,25 %, contain of Fe was 33,23 % - 76, 20 %, 6,25 % - 16,34% of Cu and 5,71 % - 8,08% of Zn was depending on the maturity of the coffee beans. In this study, homogeneity and stability testings only done to test the. The results tests of homogeneity of moisture content measurements that the candidate reference material were prepared homogeneous and remain stable (within 2 months of storage), especially to ripe green coffee beans. Isolation of compounds made by soxhletation method using methanol as a solvent. Caffeine and chlorogenic acid analysis performed by high performance thin layer chromatography (HPTLC) method using aluminum plates coated with silica gel 60F-254 as stationary phase and a mixture of ethyl-acetate: acetic acid: formic acid: water (100: 11: 11: 25, v/v/v/v) as the mobile phase. Camag TLC scanner used for scanning spektrodensitometri at 273 nm wavelength to caffeeine and to 329 nm for chlorogenic acid. TLC Scanner measurements yield information of retardation factor (Rf) values and the area. Rf values of caffeine is 0,7 and Rf values for chlorogenic acid was 0,63. Content of caffeine and chlorogenic acid was determined by comparing the sample area and an area of standards. The analysis showed that the coffee beans are prepared as a candidate reference material containing caffeine was 1,22 % - 1,28 % and 8,53 % - 9,29 % of caffeine. Result of HPTLC method for caffeine and chlorogenic acid in green coffee beans is accurate. The accurate of this method show by linearity value of caffeine was R2 = 0,9904 and R2= 0,9628 for chologenic acid. Relative standar deviasi for repeatability measurement was 1,23 % for caffeine dan 1,58 % for chlorogenic acid. Limit detection of caffeine analysis is 0,01 ppm with limit quantization is 2,33 μg. Limit detection of chlorogenic acid is 0,0552 ppm with limit quantization is 91,974 (mu)g. Persen recovery of caffeine is 98,74 % - 98,79 % and 96,24 % - 97,57 % for chlorogenic acid. Thus, green coffee beans that prepared can used as candidate reference material, especially for caffeine and chlorogenic acid determination by HPTLC.