Dinamika Pertumbuhan Lactobacillus casei dan Karakteristik Susu Fermentasi Berdasarkan Suhu dan Lama Penyimpanan

ABSTRAK. Mutu susu fermentasi sangat dipengaruhi oleh bahan baku, proses pengolahan, proses fermentasi, dan penyimpanan. Perubahan nilai gizi dapat terjadi karena variasi dan fluktuasi suhu dan penyimpanan akan mempercepat kerusakan susu fermentasi. Penelitian bertujuan untuk mempelajari pengaruh suhu dan lama penyimpanan yang berbeda pada susu fermentasi terhadap pertumbuhan L. casei dan karakteristik susu fermentasi. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) pola faktorial yang terdiri dari 2 faktor yaitu faktor A (suhu) terdiri dari a1=4-10⁰C, a2=10-16⁰C. Faktor B (lama penyimpanan) terdiri b1=0 hari b2=30 hari, b3=60 hari, b4=90 hari dan dianalisis meliputi jumlah total bakteri L. casei, nilai derajat keasaman (pH), kadar asam laktat, sineresis, dan kadar alkohol. Hasil analisis menunjukkan bahwa perlakuan suhu dan lama penyimpanan berpengaruh sangat nyata (P0.01) terhadap total bakteri, sineresis, kadar alkohol, asam laktat, tetapi pada pH terjadi interaksi antara suhu dan penyimpanan. Disimpulkan bahwa suhu dan lama penyimpanan dapat mengakibatkan pertumbuhan L. casei tidak stabil dan terjadinya perubahan karakteristik fisik susu fermentasi L. casei.  (Growth dynamics of Lactobacillus casei and characteristics of milk fermentation based on temperature and storage time) ABSTRACT. Fermented milk quality is strongly influenced by raw materials, processing, fermentation and storage. Changes in nutritional value may occur due to variations and fluctuations in temperature and storage will accelerate damage fermented milk. The research aimed to study the effect of temperature and different storage length of fermented milk on the growth of L. casei and characteristics of fermented milk. The study used completely randomized design (CRD) with factorial pattern which are consisted of two factors. Factor A (storage temperature) they were a1=4-10⁰C, a2=10-16⁰C. Factor B (storage time) they were b1=0 days, b2=30 days, b3=60 days, b4=90 days and analyzed include the total number of bacteria L. casei, the value of the degree of acidity (pH), lactic acid levels, syneresis, and alcohol content. The results showed that the temperature and storage time was highly significant (P0.01) effect the total bacteria, syneresis, alcohol level, lactic acid level, and there was interaction between temperature and storage time on pH. It can conclude that the temperature and storage time affect the growth of L. casei unstable and changes in the physical characteristics of L. casei fermented milk.