INVESTIGADORES
GOLOWCZYC Marina Alejandra
congresos y reuniones científicas
Título:
Lactobacillus paracasei isolated from kefir: probiotic and technologycal properties.
Autor/es:
L. ZAVALA; P. CARASI; GOLOWCZYC M. A.; SERRADELL M; , ABRAHAM A.G.
Reunión:
Simposio; IV Simposio Internacional de Bacterias Lácticas ? SIBAL; 2013
Resumen:
Kefir is a
probiotic beverage obtained through fermentation of milk with ?kefir
grains?. Kefir
grains are constituted by strict natural selection highly competitive microorganisms (lactic acid
bacteria, acetic acid and yeast), capable of stimulating each other and also be
able to prevent the development of other potentially pathogenic microorganisms.
Lactobacillus
paracasei is one of the species recently isolated from kefir grains that produce
acid gels with interesting rheological properties.
In order to
evaluate the potentiality of L. paracasei
as
probiotic starter some factors involved in the selection criteria
for a potentially successful probiotic were studied: resistance to artificial
gastric and intestinal juices, the adhesion capacity to the intestinal mucosa,
and the interaction of the strains with epithelial cells and Salmonella. Spray drying studies were performed in a
small-scale Büchi Mini Spray Dryer B-191, outlet temperature 70-72°C, inlet temperature 180°C.
L. paracasei strains CIDCA 8339, 83120, 83121, 83123, 83124
were used. Viability of bacterial suspensions incubated
sequentially in solutions simulating the gastric (pepsin, pH 2, 90 minutes) and
intestinal (pancreatin and bovine bile salts, pH 8, 180 minutes) compartments
was assessed. According to these results, different strains were selected and adhesion
assays to mucin and epithelial cells were performed after simulation of
gastrointestinal tract´s passage. L. paracasei CIDCA 8339 was the most resistant to
simulated gastric and intestinal fluids meanwhile L. paracasei CIDCA 83121 and CIDCA 83124 were very
sensitive to this treatment, decreasing counting at least 4 logs. For all the
bacterial strains under study, the critical step was the incubation in
simulated gastric juice. Regarding adhesion
properties, L. paracasei strains
adhered 9.5x104 ? 1x106 CFU/cm2 to mucin (9x107 CFU/cm2 were initially
inoculated) and 1.5 ? 5 CFU/cell
to Caco-2/TC-7 cells (100 CFU/cell
were initially inoculated). Gastrointestinal tract´s passage simulation
significantly increased adhesion to mucin of L. paracasei CIDCA 8339, 83123, 83124. However,
adhesion capacity to Caco-2/TC7 cells was increased only for L. paracasei CIDCA 83123 and 83124. On the other
hand, L. paracasei CIDCA 8339, 83123, 83124 were able to
reduce the invasion rate of Salmonella
to Caco-2/TC-7 cells. These 3 strains resisted well to the drying process while
maintaining a larger number of viable microorganisms (108 CFU/g
starting initially 109 CFU/g). During storage at 4°C the 3 strains maintained
the number of viable microorganisms above 1x106 CFU/g to 90 days of
storage while they lost their viability at 40 days when were stored at room
temperature.
Considering the
properties evaluated it can be conclude that L paracasei strains studied are promising strains for the
development of new foods with defined functionality.