ACRomanian Biotechnological Letters Vol. 16, No.6, 2011, Supplement Copyright © 2011 University of Bucharest Printed in Romania. All rights reserved ORIGINAL PAPER 92 The study of added prebiotics on b group vitamins concentration during milk fermentation Received for publication, September 14, 2011 Accepted, November 08, 2011 ILZE BEITANE, INGA CIPROVICA Latvia University of Agriculture, Faculty of Food Technology, 2 Liela Street, LV-3001, Jelgava, Latvia, Tel. +37163005647, Fax +37163022829, E-mail: Ilze.Beitane@llu.lv Abstract The effect of different concentrations of lactulose and inulin was studied during milk fermentation on B group vitamins: thiamin, riboflavin, pyridoxine and cobalamin concentration. The added prebiotics concentrations significantly influence the content of vitamins B 1 and B 2 (p<0.05) in fermented milk samples. The highest concentration of vitamins B 1 and B 2 was observed in fermented milk samples with 3% of lactulose and 4% of inulin. There are not established significant differences between the analyzed concentrations of prebiotics. The concentration of vitamin B 6 in fermented milk is possible to increase (p>0.05) by adding lactulose in concentrations to 3% and inulin to 4%. The type and the concentration of added prebiotics have not significant influence (p>0.05) on the concentration of vitamin B 6 in fermented milk samples. The concentration of prebiotics has the significant influence on vitamin B 12 content in fermented milk (p<0.05). There are established significant differences between control and fermented milk samples with prebiotics in concentrations of 4% and 5%, it means to increase concentrations of added prebiotics suppress the vitamin B 12 synthesis in fermented milk. Keywords: B group vitamins, prebiotics, fermented milk Introduction Growing consumer interest about nutrition for health and well-being provides the development of functional food market, where dairy-based functional foods account for nearly 43% of the market, which is almost entirely made up to fermented dairy products (ÖZER and KIRMACI [1]). Fermented functional products containing probiotics and prebiotics have important role in the development of functional foods. The adding probiotics and prebiotics increase the nutritional value of fermented milk product, due to synthesize of water soluble vitamins. Bifidobacterium strains are able to produce vitamins during milk fermentation (HUGENHOLTZ and SMID [2], CRITTENDEN et al. [3]). The ability to synthesize vitamins depends on the species of the microorganism (PAPASTOYIANNIDIS et al. [4]), which can be stimulated by adding prebiotics. Therefore the task of the research was to investigate the influence of lactulose and inulin on the ability of Bifidobacterium lactis to synthesize B group vitamins during milk fermentation. Materials and Methods The research was performed at the microbiological laboratory of the Department of Food Technology of Latvia University of Agriculture and at the laboratory of Biochemistry and Physiology of Animals of the Institute of Biology of the University of Latvia. Pasteurized milk with fat content 2.5% and the strain of Bifidobacterium lactis (Bb-12, Chr.Hansen, Denmark) were used for experiments. During the experiments, the culture was maintained at -18 o C. As prebiotics were used inulin RAFTILINE ® HP (ORAFI, Belgium) with polymerization degree ≥5 and degree of purity 99.5% and syrup of lactulose (Duphalac ® ,