PERUBAHAN KADAR PROTEIN DAN ASAM LAKTAT SUSU FERMENTASI MENGGUNAKAN STARTER Lactobacillus acidophilus SELAMA PERIODE INKUBASI ABSTRAK OLEH RAHMAN AL FARIS Suatu penelitian perubahan kadar protein dan asam laktat susu fermentasi menggunakan starter lactobacillus acidophilus selama periode inkubasi, telah dilaksanakan di Laboratorium Ilmu dan Teknologi Pengolahan Susu dari tanggal 23 Mei – 20 Juni di Fakultas Pertanian Universitas Syiah Kuala. Penelitian ini bertujuan untuk mengetahui karakteristik susu fermentasi yang menggunakan starter lactobacillus acidophilus antara lain kadar protein dan asam laktat dengan level starter yang berbeda selama masa inkubasi. Penelitian ini menggunakan metode eksperimental dan observasi dengan 2 kali ulangan. Faktor A adalah susu sapi dan faktor B merupakan lama inkubasi, b1= 0 jam, b2 = 1 jam, b3 = 2 jam, b4 = 3 jam, b5 = 4 jam, b6 = 5 jam. Hasil penelitan menunjukkan bahwa kadar protein selama periode masa inkubasi 1-4 jam menurun. Sedangkan kadar asam laktat meningkat selama periode masa inkubasi. Kata Kunci: asam laktat, protein, lactobacillus acidophilus, masa inkubasi CHANGING OF PROTEIN AND LACTIC ACID LEVEL IN FERMENTED MILK USING Lactobacillus acidophilus DURING INCUBATION PERIOD ABSTRACT BY RAHMAN Al FARIS The research about changing of protein and lactic acid level in fermented milk using Lactobacillus acidophilusduring incubation period. The objective of the research is to know the characteristic of fermented milk using Lactobacillus acidophilus as starter in different level. The research conducted at Laboratory of Milk Science Laboratory, Agricultur Departement, Syiah Kuala University, form Mei 23th until June 20th. The method used were experimental and observation with 2 replication. Treatment factors were level of starter (2, 4, and 6%) and incubation period (0, 1, 2, 3, 4, and 5 hours). The result showed that protein level during 1-4 hours incubation decreas, while lactic acid level increase during 1-5 hours incubation period. Keywords: lactic acid, protein, lactobacillus acidophilus, incubation period