E H Drosinos1, M Mataragas, P Nasis, M Galiotou, J Metaxopoulos. 1. Laboratory of Food Quality Control and Hygiene, Department of Food Science and Technology, Agricultural University of Athens, Athens, Greece. ehd@aua.gr
Abstract
AIMS: The aim of this study was to investigate the effect of pH, temperature, sodium chloride, type and level of sugar used in fermented sausages, on the occurrence and the concentration of the maximum bacteriocin activity, in order to optimize the bacteriocin synthesis during the growth cycle of Leuconostoc mesenteroides E131. METHODS AND RESULTS: In order to study the effect of the environmental factors on growth and bacteriocin production of Leuc. mesenteroides E131 fermentations were carried out in fermentor as well as in flasks. Mathematical equations were used to describe the kinetic parameters of the strain. When the micro-organism was grown in lower pH value (5.5) than optimum for growth (pH 6.5) the bacteriocin production was enhanced. On the contrary, bacteriocin production was favoured when the micro-organism was grown at temperatures close to the optimum for growth (25 degrees C). Finally, the level and the type of the sugar used as carbon source affected both growth and bacteriocin production with glucose being better source for biomass production and fructose more suitable for bacteriocin production. CONCLUSIONS: Leuconostoc mesenteroides E131 has a potential use as protective culture or its bacteriocin as protective agent in combination with another starter culture in fermented meats. SIGNIFICANCE AND IMPACT OF THE STUDY: Better understanding of the influence of environmental factors, such as pH, temperature and carbon source on the kinetic behaviour of Leuc. mesenteroides E131.
AIMS: The aim of this study was to investigate the effect of pH, temperature, sodium chloride, type and level of sugar used in fermented sausages, on the occurrence and the concentration of the maximum bacteriocin activity, in order to optimize the bacteriocin synthesis during the growth cycle of Leuconostoc mesenteroides E131. METHODS AND RESULTS: In order to study the effect of the environmental factors on growth and bacteriocin production of Leuc. mesenteroides E131 fermentations were carried out in fermentor as well as in flasks. Mathematical equations were used to describe the kinetic parameters of the strain. When the micro-organism was grown in lower pH value (5.5) than optimum for growth (pH 6.5) the bacteriocin production was enhanced. On the contrary, bacteriocin production was favoured when the micro-organism was grown at temperatures close to the optimum for growth (25 degrees C). Finally, the level and the type of the sugar used as carbon source affected both growth and bacteriocin production with glucose being better source for biomass production and fructose more suitable for bacteriocin production. CONCLUSIONS:Leuconostoc mesenteroides E131 has a potential use as protective culture or its bacteriocin as protective agent in combination with another starter culture in fermented meats. SIGNIFICANCE AND IMPACT OF THE STUDY: Better understanding of the influence of environmental factors, such as pH, temperature and carbon source on the kinetic behaviour of Leuc. mesenteroides E131.