Disruption treatments on two strains of Streptococcus thermophilus: levels of lysis/permeabilization of the cultures, and influence of treated cultures on the ripening profiles of Cremoso cheese

GUILLERMO PERALTA; BERGAMINI CARINA; ERICA HYNES

INTERNATIONAL DAIRY JOURNAL

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2019 p. 11 - 20

0958-6946

The influence of several disruption treatments on the viabilityand the release of intracellular enzymes of two strains of Streptococcusthermophilus (St1 and St2) was studied. In addition, the impact of theincorporation of disrupted cultures of St2 in Cremoso cheese wasinvestigated. We identified enzymatic (mutanolysin) and mechanicaltreatments (bead mill and ultrasound) as the most effective for lysis,while chemical methods (ethanol and SDS) were effective as permeabilizingagents; finally, physical methods (freeze and heat shock) were notsuitable for disruption. The application of disrupted cultures of St2 inCremoso cheese led to slight changes on the ripening profiles: decreaseof the lactose level, and increase of the total free amino acids and thelevels of acetic acid. This work demonstrated that certain types ofdisrupted St2 cultures could be suitable as source of key enzymes for theproduction of food with improved properties, such as lactose-hydrolyseddairy products or cheeses with higher proteolysis.