Electronic Theses and Dissertation

Proses roasting merupakan tahapan pengolahan biji kopi yang penting yang memberikan nilai tambah yang besar. Torefaksi adalah salah satu cara yang mungkin untuk mensubtitusi proses roastingdisamping dapat menghasilkan produk utama berupa biji kopi hasil torefaksi juga produk sampingan berupa asap cair dan gas.Variasi media atmosfer pada proses torefaksidiharapkan memberikan pengaruh terhadap kualitas kopi dan menghasilkanvarian produk baru.Tujuan penelitian untuk mendapatkan varian baru produk kopi yang diproses secaratorefaksi. Secara khusus penelitian bertujuan untuk menganalisa hubungan pengaruh variasi media atmosfer terhadap karakteristik termal,produk padatan, cairan dan uncondensed gas hasil torefaksi biji kopi. Biji kopi yang digunakan adalah jenis Gayo Arabika kualitas ekspor yang diperoleh dariTakengon, Aceh Tengah.Variasi media atmosfer yang digunakan adalah udara, nitrogen dan argon. Ujitorefaksi terhadap biji kopi dengan variasi media atmosfer dilakukan dengan dua metode. Pertamadenganmetode TGAterhadap sampel biji buah kopi dengan massa 5 g. Tiap pengujian juga dilakukan variasi temperature rate 10 dan 20 oC.menit-1.Data hasil pengujian didapat berupa laju kenaikan temperatur terhadap waktu (oC.s-1), penurunan massa terhadap kenaikan temperatur (mg.oC-1) & waktu (mg.s-1).Selanjutnya pengujian dilakukandengan fixed-bed torrefier dengan massa 200 gr pada temperatur 235oC dan waktu 60 menit untuk mendapatkan data pengaruh variasi atmosfer terhadap produk utama dan produk sampingan.Produk utama berupa biji kopi hasil torefaksi dilakukan ujikualitas lebih lanjut dengan metode uji SEM+EDX+Mapping untuk mendapatkan data morfologi & komposisinya, uji UV-Vis untuk mendapatkankadar kafein & asam klorogenat, uji colorimeter untuk mendapatkan skala warna dan uji organoleptik untuk mendapatkan kualitas aroma dan rasa.Produk sampingan berupa asap cair kemudian diuji karakteristiknya (pH, densitas, viskositas dan warna) dan uji FTIR untuk mendapatkan gugus fungsinya serta uji komposisinyadengan GC-MS. Temperatur asap (fumi) dan udara (aria) serta kadar CO (ppm) dari uncondensed gas diukur dengan peralatan testo meter.Data dianalisis secara statistik untuk mendapatkan pengaruh variasi media atmosfir terhadap kualitas kopi yang diTorefaksi.Hasil pengujian menunjukkan bahwa variasi media atmosfer berpengaruh terhadap: (1) penurunan massa namun tidak terhadap temperatur biji kopi yang ditorefaksi; (2) profil temperatur proses torefaksi dan pendinginan biji kopi terhadap waktu; (3) yield solid, liquid dan gas; (4) pH, kandungan caffeine, asam chlorogenat, kandungan atom, aroma, flavor, after taste, acidity&balance, namun tidak signifikan terhadap nilai warna RGB dan CIE L*a*b*; (5) kandungan gugus fungsi dan kandungan senyawa liquid hasil uji FTIR dan GC-MS, namun tidak signifikan terhadap pH, densitas dan viskositasnya; (6) selisih antara temperatur fumi dan aria serta distribusi CO dalam gas. Sehingga dapat disimpulkan bahwa variasi media atmosfer pada proses Torefaksibiji kopi telah memberikan pengaruh terhadap kualitas kopi dan menghasilkan varian baru baik untuk produk padatan, cairan maupun gas dari kopi.

Roasting is an important step in the processing of coffee beans that adds significant value. Torrefaction is a roasting alternative that produces torrefied coffee beans as well as liquid smoke and gas byproducts. Variations in the atmosphere during the torrefaction process are expected to have an impact on coffee quality and lead to the development of new product variants. The study's goal is to create a new torrefied coffee product. Its specific goal is to determine the relationship between the impact of differences in atmospheric media on thermal properties and the product characteristics of solids, liquids, and uncondensed gas resulting from coffee bean torrefaction. Gayo Arabica coffee beans of export quality from the Central Aceh area of Takengon are used.The various atmospheric media used are air, nitrogen, and argon. Torrefaction of coffee beans in various atmospheric media was tested using two methods. The first is the termogravimetry method on 5 g coffee bean samples. Each test was also run with temperature rate variations of 10 and 20 oC.min-1.The rate of increase in temperature with respect to time (oC.s-1) and the decrease in mass with increasing temperature (mg.oC-1) and time(mg.s-1) are obtained from the test results. Further tests were performed with a fixed-bed torrefier weighing 200 g of raw material at 235 oC for 60 minutes to determine the effect of atmospheric variations on the main product and by-products. Torefied coffee beans are subjected to additional quality tests, including the SEM+EDX+Mapping test method for morphological and compositional data, the UV-Vis test for caffeine and chlorogenic acid levels, the colorimeter test for a color scale, and the organoleptic test for aroma and taste qualities.The by-product, liquid smoke, is then tested for its properties (pH, density, viscosity, and color) and analyzed by FTIR to determine its functional groups, as well as GC-MS for composition.A testometer was used to measure the temperatures of smoke (fumi) and air (aria), as well as the CO levels (ppm) of uncondensed gas.The data were analyzed statistically to determine the effects of variations in atmospheric media on the quality of torrefied coffee.Variations in atmospheric media affect: (1) the decrease in mass but not the temperature of torrefied coffee beans; (2) the temperature profile of torrefaction and cooling of coffee beans over time; (3) solid, liquid, and gas yields product; (4) pH, caffeine content, chlorogenic acid, atomic content, aroma, flavor, aftertaste, acidity & balance, but not the RGB and CIE L*a*b* color values; (5) the content of functional groups and the content of liquid compounds as a result of FTIR and GC-MS tests, but not significant to pH, density, or viscosity, and; (6) the difference between the temperature of the fumi and aria and the distribution of CO in the gas.As a result, it can be concluded that variations in atmospheric media during the torrefaction process of coffee beans influenced coffee quality and produced new variants for solid, liquid, and gas coffee products.