Electronic Theses and Dissertation

Kopi merupakan komoditas pertanian yng memiliki nilai ekonomis yang tinggi dan berperan dalam menyumbang devisa negara. Kualitas dan citarasa kopi dipengaruhi oleh beberapa hal, salah satunya adalah fermentasi salah satunya adalah kopi luwak. Tingginya minat konsumen dan nilai ekonomi terhadap kopi luwak, membuat banyak orang memburu luwak untuk dipelihara. Hal ini menuai isu kesejahteraan hewan karena penangkaran luwak yang sering tidak ideal. Fermentasi kopi luwak secara in-vitro dengan inokulum feses luwak menjadi alternatif untuk meniru fermentasi alami tanpa mengeksploitasi hewan, namun proses ini dapat menurunkan pH sehingga meningkatkan keasaman berlebih. Oleh karena itu, penggunaan buffer pH seperti soda kue dan amonia kue diperlukan untuk menstabilkan pH, mendukung aktivitas mikroba, menurunkan kadar kafein, dan menjaga cita rasa kopi agar tetap berkualitas seperti kopi luwak alami. Penelitian ini bertujuan untuk menganalisis karakteristik sifat fisiko-kimia biji kopi yang dihasilkan pada fermentasi kopi luwak in-vitro dengan penambahan edible buffer pH.
Adapun penelitian ini dilakukan di Laboratorium Teknik Pasca Fakultas Pertanian Universitas Syiah Kuala pada bulan Mei- Juli 2025. Kopi gelondong arabika dan feses luwak yang berasal dari perkebunan kopi di Kabupaten Bener Meriah. Feses luwak sebanyak 500g diinokulasi selama 10 hari dengan penambahan medium 500 ml setiap harinya. Kemudian kopi arabika sebanyak 3.500g difermentasi menggunakan 700 ml inokulum feses luwak selama 48 jam dengan suhu 37°C dalam keadaan anaerob. Fermentasi dilakukan denagan 3 perlakuan yaitu fermentasi tanpa penambahan buffer pH (B0), fermentasi dengan penambahan buffer pH soda kue (B1) dan fermentasi dengan penambahan buffer pH amonia kue(B2) sebanyak 1 %. Sampel diambil secara berkala pada waktu 0 jam, 2 jam, 4 jam, 8 jam ,12 jam, 24 jam, 30 jam, 36 jam, 42 jam, dan 48 jam untuk dianalisis kadar pH, Total Asam Tertitrasi, kadar air, dan kadar kafein.
Hasil penelitian menunjukkan bahwa pH kopi luwak fermentasi in-vitro menurun pada semua perlakuan seiring lama fermentasi, dengan penurunan terbesar pada B0 dari 5,43 menjadi 4,75, sedangkan pada B1 dan B2 mampu menahan penurunan pH hingga 5,23 dan 5,28. TAT meningkat pada semua perlakuan dengan nilai tertinggi terdapat pada perlakuan B0 yaitu 0,0473% diikuti dengan perlakuan B2 yaitu 0,0338% dan B1 yaitu 0,0315%. Kadar air mengalami kenaikan pada semua perlakuan dengan kadar air awal 69,87% menjadi 71,84 pada perlakuan B0, 74,89% pada perlakuan B1 dan 73,96% pada perlakuan B2. Penggunaan buffer pH meningkatkan kadar air karena medium semi-basa membantu menjaga kelembapan biji kopi. Kadar kafein mengalami penurunan untuk semua perlakuan, dengan nilai kafein awal 2,22%b/b. Perlakuan B0 mengalami susut kafein sebesar 37,28 % dengan kadar kafein akhir menjadi 1,38%b/b, perlakuan B1 susut kafein sebesar 51,18% dengan kadar kafein akhir 1,16%b/b , dan penurunan terbesar pada perlakuan B2 menjadi 1,00%b/b dengan susut kafein sebesar 51,66% dikarenakan pengguna amonia kue yang mengandung nitrogen menghasilkan lingkungan fermentasi dengan pH stabil yang mendukung aktivitas mikroba.

Coffee is an agricultural commodity with high economic value that contributes to the country's foreign exchange earnings. The quality and taste of coffee are influenced by several factors, one of which is fermentation, such as in the case of civet coffee. The high consumer interest and economic value of civet coffee has led many people to hunt civets for breeding. This has raised animal welfare issues because civet breeding is often not ideal. In-vitro fermentation of luwak coffee with civet feces inoculum is an alternative to mimic natural fermentation without exploiting animals, but this process can lower the pH, thereby increasing excess acidity. Therefore, the use of pH buffers such as baking soda and baking ammonia is necessary to stabilize the pH, support microbial activity, reduce caffeine levels, and maintain the taste of the coffee so that it remains as high quality as natural luwak coffee. This study aims to analyze the physicochemical characteristics of coffee beans produced in in-vitro luwak coffee fermentation with the addition of edible pH buffers. This research was conducted at the Postgraduate Engineering Laboratory, Faculty of Agriculture, Syiah Kuala University, from May to July 2025. Arabica coffee beans and luwak feces were sourced from coffee plantations in Bener Meriah Regency. A total of 500 g of luwak feces was inoculated for 10 days with the addition of 500 ml of medium every day. Then, 3,500 g of Arabica coffee beans were fermented using 700 ml of civet feces inoculum for 48 hours at 37°C under anaerobic conditions. Fermentation was carried out with three treatments, namely fermentation without the addition of a pH buffer (B0), fermentation with the addition of a baking soda pH buffer (B1), and fermentation with the addition of a 1% baking ammonia pH buffer (B2). Samples were taken periodically at 0 hours, 2 hours, 4 hours, 8 hours, 12 hours, 24 hours, 30 hours, 36 hours, 42 hours, and 48 hours to analyze the pH level, total titratable acidity, moisture content, and caffeine content. The results showed that the pH of in-vitro fermented civet coffee decreased in all treatments as fermentation time increased, with the greatest decrease in B0 from 5.43 to 4.75, while B1 and B2 were able to maintain pH levels of 5.23 and 5.28, respectively. TAT increased in all treatments, with the highest value found in treatment B0 at 0.0473%, followed by treatment B2 at 0.0338% and B1 at 0.0315%. The moisture content increased in all treatments, with the initial moisture content of 69.87% becoming 71.84% in treatment B0, 74.89% in treatment B1, and 73.96% in treatment B2. The use of a pH buffer increased the moisture content because the semi-alkaline medium helped maintain the moisture of the coffee beans. Caffeine content decreased for all treatments, with an initial caffeine value of 2.22% w/w. Treatment B0 experienced a 37.28% decrease in caffeine, with a final caffeine content of 1.38% w/w, treatment B1 experienced a 51.18% decrease in caffeine, with a final caffeine content of 1.16% w/w, and the largest decrease in treatment B2 to 1.00% w/w with a caffeine reduction of 51.66% due to the use of nitrogen-containing baking ammonia, which produced a fermentation environment with a stable pH that supported microbial activity.