title: Kluyveromyces lactis but not Pichia fermentans used as adjunct culture modifies the olfactory profiles of Cantalet cheese.
abstract: Yeasts are commonly detected in cheese. Two yeast species, Kluyveromyces lactis and Pichia fermentans, were isolated at high populations from raw-milk Cantalet cheese, a French Protected Denomination of Origin hard cheese. To investigate the interest of these 2 species as adjunct cultures to promote flavor development of Cantalet cheese, they were added at 10(5) cfu/mL to microfiltered milk. The global microbiological, biochemical, and flavor changes induced by the presence of the yeasts in cheese were determined. Adjunct yeasts were present at 10(6) cfu/g in curd, declined to 10(4) to 10(5) cfu/g in cheese, and did not influence gross composition, content of free amino acids, or content of free fatty acids. By using 8-way gas chromatography-olfactometry in parallel with gas chromatography-mass spectrometry, 30 odorous compounds of Cantalet cheese were identified. The olfactory profiles of K. lactis cheeses contained significantly greater levels of 8 odorous compounds (ethanol, ethyl hexanoate, 4 aldehydes, and 2 branched-chain acids) compared with the control and P. fermentans cheeses. Sensory analysis of cheeses flavor discriminated K. lactis cheeses on only 2 attributes (acetaldehyde and alcohol odors). This study shows that yeast contribution is species-specific and that K. lactis, at a population of 10(6) viable cells/g, can influence Cantalet cheese flavor.
authors.affiliation: Les Fromageries Occitanes (LFO), Borde Blanche - Zone Industrielle, F-31290 Villefranche de Lauragais, France.
authors.forename: I
authors.initials: I
authors.lastname: De Freitas
authors.forename: N
authors.initials: N
authors.lastname: Pinon
authors.forename: J-L
authors.initials: JL
authors.lastname: Berdagué
authors.forename: P
authors.initials: P
authors.lastname: Tournayre
authors.forename: S
authors.initials: S
authors.lastname: Lortal
authors.forename: A
authors.initials: A
authors.lastname: Thierry
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002611:Cheese / Q000382:microbiology*; D015169:Colony Count, Microbial; D005230:Fatty Acids, Nonesterified / Q000032:analysis; D005516:Food Microbiology; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007716:Kluyveromyces / Q000254:growth & development* / Q000378:metabolism; D009812:Odorants; D010843:Pichia / Q000254:growth & development* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D005230:Fatty Acids, Nonesterified