Evaluación de la fermentación del lactosuero ácido (entero y desproteinizado) utilizando Lactobacillus casei

The spontaneously acidified whey threatens consumers' health and reduces quality of mozzarella cheese. The goal of this research was to evaluate the acidification process of acid whey (whole and deproteinized) by fermentation with different inoculum concentrations of Lactobacillus casei. The whey was physicochemically characterized and anaerobically fermented at 37°C and120 rpm during 96h. Cellular biomass was evaluated, as well as lactose consumption, lactic acid production, kinetic and stoichiometric parameters were estimated. A completely randomized design with factorial arrangement (2x3) was applied by using the repeated measures methodology. Data was processed by using SAS® statistical package, version 9 and Statgraphics Centurion XVI®. The acidification for the whole and deproteinized whey was found within the acceptable intervals. Acidification values were above 120 degrees Dornic (120°D) with L. casei inoculation, except in deproteinized whey inoculated with 15% of inoculum. The whole whey with 15% of inoculum reached 120°D in the shortest time (34 hours). High concentrations of inoculum (15%) aided the acidification in whole whey and showed the highest production (20.83 g LA/l), and p/s=0.86, Qp=0.173 g AL/l*h; on the other hand, deproteinized whey showed the highest microbial growth, lowest conversion of lactose (8.2%) and lowest lactic acid production (8.19g/l).