title: Selenite biotransformation during brewing. Evaluation by HPLC-ICP-MS.
abstract: Yeast (Saccharomyces cerevisiae) and lactic bacteria have shown their ability to accumulate and transform inorganic selenium into organo Se compounds. The objective of this work was to evaluate selenium biotransformation during brewing by using S. cerevisiae and Saccharomyces uvarum for Ale and Lager fermentation, respectively. Se-enriched beer was produced by the addition of sodium selenite (0, 0.2, 1.0, 2.0, 10.0, 20.0 μg Se mL(-1), respectively) to the fermentation media composed of yeast, malt extract and water. The alcoholic fermentation process was not affected by the presence of selenium regardless of the type of Saccharomyces being used. The percentage of selenium incorporated into beer, added between 1.0 and 10 μg mL(-1) was 55-60% of the selenium initially present. Se-compounds in post-fermentation (beer and yeast) products were investigated by using an analytical methodology based on HPLC-ICP-MS. For this purpose, several sample treatments, including ultrasonic-assisted enzymatic hydrolysis, in conjunction with different separation mechanisms like dialysis and anion exchange HPLC chromatography were applied for unambiguously identifying Se-species that produce during brewing. Selenomethionine was the main selenium compound identified in beer and yeast, being this species in the only case of the former not associated to peptides or proteins.
authors.affiliation: Departamento de Química Analítica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Avda Complutense s/n. 28040 Madrid, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Sánchez-Martínez
authors.forename: Erik Galvão P
authors.initials: EG
authors.lastname: da Silva
authors.forename: Teresa
authors.initials: T
authors.lastname: Pérez-Corona
authors.forename: Carmen
authors.initials: C
authors.lastname: Cámara
authors.forename: Sergio L C
authors.initials: SL
authors.lastname: Ferreira
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Madrid
mesh_terms: D001515:Beer / Q000032:analysis*; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D005285:Fermentation; D013058:Mass Spectrometry; D012440:Saccharomyces / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D012645:Selenomethionine / Q000032:analysis*; D018038:Sodium Selenite / Q000032:analysis*; D013054:Spectrophotometry, Atomic
chemical_list: D012645:Selenomethionine; D018038:Sodium Selenite