Comparison of the acidifying activity of Lactococcus lactis subsp. lactis strains isolated from goat's milk and Valdeteja cheese.
OBJECTIVE
This work was carried out to study the acid production by Lactococcus lactis subsp. lactis strains isolated from goat's milk and goat cheese (Valdeteja variety) in order to select a suitable starter culture for industrial goat cheese manufacturing.


RESULTS
The titrable acidity of 45 Lactococcus lactis subsp. lactis strains isolated from a home-made batch of Valdeteja cheese with excellent sensory characteristics was measured over a period of 18 h. The strains were divided into two groups depending on the acid production rate: 20 fast acid producer (F) strains and 25 slow acid producer (S) strains. The kinetic parameters (lag phase, maximum acid production rate and value of upper asymptote curve) of the acid production curves for F and S strains were significantly (P < 0.001) different.


CONCLUSIONS
Significant (P < 0.001) differences between titrable acidity of F and S strains were observed after the second hour of incubation.


CONCLUSIONS
An F strain acetoin producer (Lactococcus lactis subsp. lactis 470Ch2) was selected as autochthonous starter culture for industrial Valdeteja goat cheese manufacturing.
Alonso-Calleja
C
C
Departamento de Higiene y Tecnología de los Alimentos, Facultad de Veterinaria, Universidad de León, Campus Universitario de Vegazana, s/n. 24071, León, Spain. dhtcac@unileon.es
Carballo
J
J
Capita
R
R
Bernardo
A
A
García-López
M L
ML
D000818:Animals; D002611:Cheese / Q000382:microbiology*; D003470:Culture Media; D005516:Food Microbiology; D006041:Goats; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000378:metabolism*; D013294:Lactococcus lactis / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D008892:Milk / Q000382:microbiology*
D003470:Culture Media; D019344:Lactic Acid