Lacto-dynamographic Study of Lactic Acid Bacteria as a Tool for Their Selection P. Micari, A. Caridi*
“Mediterranea” University of Reggio Calabria, Department of Agro-Forestry and Environmental Technology and Science, Italy
acaridi@unirc.it
The lacto-dynamograph provides, through a diapason tracing, a graphic image of the milk coagulation mechanisms by means of three parameters, that are correlated to several curd characteristics: rennet coagulation time (r in min), curd firming rate (k20 in min) and curd
firmness (a30 in mm) measured 30 min after the addition of rennet. This allows a simple and
quick identification of animals that produce over-reactive or under-reactive milk, regarding rennet.
Lactic acid bacteria are involved in the production of a variety of fermented foods. The selection of starter cultures for cheesemaking is performed on the basis of numerous characteristics, also in some way referred to their role in cheese rheology.
The aim of this research has been to develop a method to directly screen lactic acid bacteria regarding their coagulation properties using the lacto-dynamographic technique. Therefore, several autochthonous strains of lactic acid bacteria, previously isolated from Italian raw milk cheeses, have been inoculated in pasteurised goats’ and ewes’ milk and studied using a lacto-dynamograph to determine their behaviour.
The lacto-dynamographic analysis of lactic acid bacteria-inoculated milks shows different types of tracing and, on the whole, an interesting biodiversity among the tested strains. This simple and quick screening method could give the opportunity to easily perform a pre-selection of a high number of strains, discriminating lactic acid bacteria regarding their coagulation properties.
Keywords: lacto-dynamographic analysis, coagulation parameters, lactic acid bacteria, pre-selection