Technological aptitudes instability of the thermophilic lactic acid bacteria used in emmental-type cheesemaking.

Citation
A. Thomas et Jf. Chamba, Technological aptitudes instability of the thermophilic lactic acid bacteria used in emmental-type cheesemaking., SCI ALIMENT, 20(1), 2000, pp. 159-167
Citations number
15
Language
FRANCESE
art.tipo
Article
Categorie Soggetti
Food Science/Nutrition
Journal title
SCIENCES DES ALIMENTS
ISSN journal
0240-8813 → ACNP
Volume
20
Issue
1
Year of publication
2000
Pages
159 - 167
Database
ISI
SICI code
0240-8813(2000)20:1<159:TAIOTT>2.0.ZU;2-E
Abstract
Technological aptitudes of thermophilic lactic acid bacteria evolve through successive generations. In order to study this phenomenon, 21 strains were grown in different culture conditions where we changed the media compositi on and the growth temperature until we obtained about 250 generations. Acid ifying activity, lysozyme resistance, aminopeptidasic activity, sensitivity to phages and lysogenic property of the strains were evaluated before, dur ing and after each culture series. The most unstable activity was the acidi fying activity: the strains which were growing on broth at 44 degrees G sho wed mainly a variation of their acidifying activity measured at 44 degrees C; cultures in emmental-type thermal cycle usually showed an increased acti vity when strains were grown on milk and a decreased one when they were gro wn on broth. Three different origins of variation have been identified: clo nal heterogeneity of the strains, transitory adaptation of the strains to t he growth conditions and finally, selection of stable populations displayin g new characteristics compared with the ancestral strain.