344 Bulletin UASVM Agriculture, 69(2)/2012 Print ISSN 1843-5246; Electronic ISSN 1843-5386 Evaluation of Some Factors with Significant Influence on Functionality and Viability of Probiotic Strains LA-5 ® and L. Casei 431 ® in Multiple Starter Cultures in Mesophilic Fermented Milk Daniela PARASCHIV 1) , Aida VASILE 2) , Gabriela BAHRIM 2) 1) Chr. Hansen SRL, 106A Zizinului Street, Brasov Romania, rodpa@chr-hansen.com 2) “Dunarea de Jos” University of Galati, Faculty of Food Science and Engineering, 111 Domneasca Street, Galati, Romania Abstract. For a very long time, probiotics have been selected on the basis of their suitability to food’s environment and technological procedures, as well as survival ability in vitro and also in vivo. These criteria are still used. The aim of this study was to select, using the Plakett–Burman design of experiments model, of three significant factors, which influence the multiplication ability and viability of probiotic strains Lactobacillus acidophilus (commercial code LA-5 ® ) and Lactobacillus casei subsp. paracasei (commercial code L. casei 431 ® ) in fermented mesophilic milk product (commercial named Sana) obtained by fermentation with a multiple culture with mesophilic lactic starter Flora Danica Chr. Hansen commercial starters (Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. diacetylactis and Leuconostoc mesenteroides subsp. cremoris). By statistical analysis the most important factors (independent variables) with influence on the probiotic bacteria were selected for the optimized. These are the temperature of fermentation; the ratio between probiotic strains and Flora Danica and the addition of prebiotic Fagopyrum esculentum flour. In the future experiments the optimum values of these parameters will be optimized by using response surface methodology, in order to establish the conditions in which can be obtain the mesophilic fermented milk products with probiotic action in vivo. Keywords: probiotics, prebiotic, LA-5 ® , L. casei 431 ® , Flora Danica, multiple starter cultures INTRODUCTION In last years, at global level we observed an increased in consumption of fermented milks, in special fermented milk products with probiotics (Charvalh et al., 2004). Probiotics are defined as viable microorganisms which presents a beneficial effect on the health condition of consumer, through the improving of his intestinal microbial balance (Arunachalam, 2000; Galdeano and Perdigón, 2006; Sandholm et al., 2002). The addition of probiotics in fermented dairy products is realized not only as a consequence of beneficial effects on consumers’ health, but also for the extension of the probiotic products range (Gilliland, 1989). Symbiotic, o combination of probiotics with prebiotics could induce supplementary positive effects on consumer’s health (Katharina et al., 2007; Luo et al., 2011). In this way the development of new synbiotic dairy products by combine probiotics with prebiotics leads to improve the quality and functionality of the fermented dairy products. Buckwheat flour is a rich source of a special type of starch with dietary lipids and contains many valuable compounds, such as proteins with a low content of α-gliadin fraction, antioxidative substances trace elements and dietary fibre Proteins content in buckwheat flour has been reported to range from 8.5 to 18.9%, depending on the variety. Buckwheat proteins have a high biological value due to well-balanced amino-acids composition (Wronkowska et al., 2008).