title: Impact of polyunsaturated fatty acid degradation on survival and acidification activity of freeze-dried Weissella paramesenteroides LC11 during storage.
abstract: The impact of polyunsaturated fatty acid (PUFA) degradation on the survival and acidification activity of freeze-dried Weissella paramesenteroides LC11 was investigated over 90-days storage at 4 degrees C or 20 degrees C in vacuum-sealed aluminium foil or glass tubes with two water activities (a(w)=0.11 or 0.23). Colony counts, acidification activity (% lactic acid/g), linoleic/palmitic (18:2/16:0) or linolenic/palmitic (18:3/16:0) ratio by gas chromatography and 18:2 or 18:3 oxylipins by reversed phase-high performance liquid chromatography were determined. The viable cells, acidification activity and 18:2/16:0 or 18:3/16:0 ratio decreased as the storage time increased. The survival, acidification activity and 18:2/16:0 or 18:3/16:0 ratio were greatest for the freeze-dried strain held in vacuum-sealed aluminium foil at 4 degrees C. The 18:2/16:0 or 18:3/16:0 ratio decrease was correlated with the accumulation of 18:2 or 18:3 oxylipins during storage in glass tubes. Hydroperoxy PUFAs, hydroxy PUFAs, divinyl ether PUFAs and oxo PUFAs were the main oxylipins identified. A large decrease in the 18:2/16:0 or 18:3/16:0 ratio and a rapid accumulation of oxylipins during storage might be enough to cause high cell death and loss of metabolic activity. These results provide further experimental support for the hypothesis that lipid oxidation and survival or activity of freeze-dried bacteria might be related.
authors.affiliation: Wallon Center for Industrial Biology, Microbial Technology Unit, University of Liège, Sart-Tilman B40, 4000 Liège, Belgium. AmenanAnastasie.Yao@student.ulg.ac.be
authors.forename: Amenan A
authors.initials: AA
authors.lastname: Yao
authors.forename: Ibourahema
authors.initials: I
authors.lastname: Coulibaly
authors.forename: Georges
authors.initials: G
authors.lastname: Lognay
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Fauconnier
authors.forename: Philippe
authors.initials: P
authors.lastname: Thonart
mesh_terms: D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism* / Q000494:pharmacology; D005516:Food Microbiology; D005612:Freeze Drying / Q000379:methods*; D019344:Lactic Acid / Q000378:metabolism*; D050296:Microbial Viability / Q000187:drug effects*
chemical_list: D005231:Fatty Acids, Unsaturated; D019344:Lactic Acid