71 EFFECTS of PREBIOTICS on GROWTH and ACIDIFYING ACTIVITY of PROBIOTIC BACTERIA Abstract In this study, in vitro effects of six commercial prebiotics on growth and acidifying activity of two strains of Lactobacillus acidophilus and two strains of Bifidobacterium spp. were investigated. Fructo- oligosaccharide, inulin, galacto-oligosaccharide, soybean oligosaccharide, xylo-oligosaccharide and lactulose were used as prebiotics. The prebiotics were tested at three different concentrations. Growth and acidifying activity of the probiotic bacteria were variable depending on the type and concentration of the prebiotics. In general, as the concentration of the prebiotics increases, the growth and acidifying activity performance of the probiotic strains increases. The difference in the strains of L. acidophilus was not significant in terms of both growth performance and acidifying activity. However, the difference in the species of Bifidobacterium was found to be significant (P<0.05). The results of this study indicated that an appropriate prebiotic substance should be selected for each probiotic bacterial strain for its good growth and acidifying performance. Keywords: Prebiotics, probiotic bacteria, Lactobacillus acidophilus, Bifidobacterium spp., growth, acidifying activity. PREBİYOTİKLERİN PROBİYOTİK BAKTERİLERİN GELİŞMESİ ve ASİTLEŞTİRME AKTİVİTELERİ ÜZERİNE ETKİLERİ Özet Bu çal›flmada alt› adet ticari prebiyotik maddenin in vitro koflullarda iki adet Lactobacillus acidophilus suflu ve iki adet Bifidobacterium spp. suflunun geliflme ve asitlefltirme aktivitesi üzerindeki etkileri araflt›r›lm›flt›r. Prebiyotik olarak frukto-oligosakkarit, inulin, galakto-oligosakkarit, soya fasulyesi oligosakkariti, ksilo-oligosakkarit ve laktuloz kullan›lm›flt›r. Prebiyotikler üç farkl› konsantrasyonda denenmifltir. Probiyotik bakterilerin geliflme ve asitlefltirme aktivitesi üzerindeki etkileri prebiyotik çeflidine ve konsantrasyonuna ba¤l› olarak de¤iflim göstermifltir. Genel olarak, prebiyotik konsantrasyonu artt›kça, probiyotik bakteri sufllar›n›n geliflme performans› ve asitlefltirme aktivitesinde art›fllar meydana gelmifltir. L. acidophilus türündeki sufl farkl›l›¤›, sufllar›n geliflme performans› ve asitlefltirme aktivitesi üzerinde önemli bir etki yaratmam›flt›r. Buna karfl›l›k Bifidobacterium cinsindeki tür farkl›l›¤›n›n bu yönlerdeki etkisi önemli bulunmufltur (P<0.05). Araflt›rma sonuçlar›, bir probiyotik bakteri suflunun iyi bir geliflme ve asitlefltirme performans› gösterebilmesi için ona uygun bir prebiyotik madde seçilmesinin gereklili¤ine iflaret etmektedir. Anahtar Kelimeler: Prebiyotikler, probiyotik bakteriler, Lactobacillus acidophilus, Bifidobacterium spp., geliflme, asitlefltirme aktivitesi Ayla Şener Mumcu 1 , Ayhan Temiz 2 * 1 Republic of Turkey Ministry of Food, Agriculture and Livestock, Bodrum District Directorate, Mu¤la Provincial Control Directorate, Mu¤la, Turkey 2 Hacettepe University, Faculty of Engineering, Department of Food Engineering, Ankara, Turkey Received / Gelifl tarihi: 13.01.2014 Accepted / Kabul tarihi: 17.01.2014 Research / Araflt›rma * Corresponding author / Yazışmalardan sorumlu yazar;  temiz@hacettepe.edu.tr, ✆ (+90) 312 297 7101, (+90) 312 299 2123 GD14011-66375 GIDA (2014) 39 (2): 71-77 doi: 10.5505/gida.66375