xii RINGKASAN
Soyghurt adalah susu kedelai yang difermentasi oleh bakteri probiotik.
Faktor-faktor yang mempengaruhi fermentasi adalah suhu dan lama inkubasi. Bakteri asam laktat (BAL) yang digunakan dalam pembuatan soyghurt di antaranya Lactobacillus bulgaricus, Streptococcus thermophillus, dan Bifidobacterium sp. dengan suhu optimal pertumbuhan 36°-37°C dan lama inkubasi berkisar 1-2 hari. BAL diketahui mampu menghasilkan bakteriosin yang dapat menghambat bakteri patogen dalam saluran pencernaan salah satunya ialah Bacillus cereus. Tujuan penelitian ini ialah mengetahui perbandingan BAL pada soyghurt terhadap daya hambat B. cereus, mengetahui lama inkubasi soyghurt dengan penambahan Bifidobacterium sp terhadap pertumbuhan B. cereus, dan mengetahui pengaruh
konsentrasi BAL dan lama inkubasi pada soyghurt terhadap pertumbuhan B. cereus. Metode yang digunakan adalah metode eksperimental menggunakan Rancangan Acak Lengkap (RAL) pola faktorial, setiap perlakuan diulang sebanyak 3 kali. Faktor pertama yaitu lama inkubasi soyghurt yang diberi penambahan Bifidobacterium sp. pada suhu 37oC. Parameter utama yang diamati adalah daya hambat soyghurt dengan tambahan Bifidobacterium sp. terhadap B. cereus (Uji difusi). Data yang diperoleh dianalisis menggunakan analisis ragam pada tingkat kesalahan 1 % dan 5 %. Apabila perlakuan berpengaruh nyata atau sangat nyata dilanjutkan uji Beda Nyata Jujur (BNJ). Hasil penelitian menunjukkan perbandingan BAL (L. bulgaricus : S. thermophillus : Bifidobacterium sp.) 1:1:1 (K1) pada soyghurt mampu menghambat B. cereus. Lama inkubasi soyghurt dengan penambahan Bifidobacterium sp. optimal pada 24 jam terhadap pertumbuhan B. cereus. Konsentrasi BAL dengan lama inkubasi pada soyghurt tidak mampu
meningkatkan daya hambat pertumbuhan B.cereus.
Kata kunci : Bifidobacterium sp., perbandingan, lama inkubasi, soyghurt, suhu fermentasi.
xiii SUMMARY
Soyghurt is fermented soy milk produced by probiotic bacteria. Some factors that affect the temperature and fermentation is long incubation. Lactic acid bacteria
(LAB) are used in the making of soyghurt such Lactobacillus bulgaricus, Streptococcus thermophillus, and Bifidobacterium sp. with optimum growth
temperature at 36° - 37° C and the incubation time ranges from 1-2 days. LAB is known able to produce bacteriocins that can inhibit pathogenic bacteria in the digestive tract such as Bacillus cereus. The purpose of this study was to determine the ratio of LAB on soyghurt on inhibition of B. cereus, determine the length of incubation soyghurt with the addition of Bifidobacterium sp. on the growth of B. cereus, and determine the effect of LAB concentrations and longer incubation at
soyghurt on the growth of B. cereus.
The method used in this study was an experimental method using completely randomized design (CRD) factorial design and each treatment was repeated 3 times. The first factor was soyghurt incubation time with an addition of Bifidobacterium sp. at 37 ° C. The main parameter which observed was soyghurt with Bifidobacterium sp inhibition ability against B. cereus (diffusion test). Data were analyzed using analysis of variance on the error rate at 1% and 5%. The Honest Significant Difference (HSD) test will be held if the treatment take a tangible or very tangible effect. The results show a comparison of LAB (L. bulgaricus : S. thermophillus : Bifidobacterium sp.) 1: 1: 1 (K1) on soyghurt able to inhibit B. cereus. Long incubation soyghurt with the addition of Bifidobacterium sp. optimal at 24 hour on the growth of B. cereus. LAB concentration with a long incubation at soyghurt not able to increase the growth inhibitory B.cereus.
Keywords: Bifidobacterium sp., comparison, incubation time, soyghurt, fermentation temperature.
