title: Oxygen deficiency in barley (Hordeum vulgare) grain during malting.
abstract: The steep water is generally aerated in industrial barley malting. However, it is questionable whether oxygen actually reaches the embryo, which remains entrapped under the husk, testa, and pericarp until chitting occurs. The aim of our study was to investigate whether barley embryos experience oxygen deficiency during steeping, and whether various steeping conditions affect the oxygen deficiency. Alcohol dehydrogenase Adh2 was induced in all steeping conditions studied. Therefore, oxygen deficiency occurred regardless of the steeping conditions. However, steeping conditions affected the rate of recovery from oxygen deficiency, germination rate, and onset of alpha-amylase production. When barley was subjected to oxygen deficiency by applying N(2) gas during steeping, the timing of the treatment determined its effects. The importance of aeration increased as the process proceeded. Oxygen deprivation at the beginning of the process had little effect on malt quality. Therefore, the timing of aeration is important in the optimization of germination during the steeping stage of malting.
authors.affiliation: VTT Biotechnology, P.O. Box 1500, FI-02044 VTT, Finland. annika.wilhelmson@vtt.fi
authors.forename: Annika
authors.initials: A
authors.lastname: Wilhelmson
authors.forename: Arja
authors.initials: A
authors.lastname: Laitila
authors.forename: Arvi
authors.initials: A
authors.lastname: Vilpola
authors.forename: Juhani
authors.initials: J
authors.lastname: Olkku
authors.forename: Erja
authors.initials: E
authors.lastname: Kotaviita
authors.forename: Kurt
authors.initials: K
authors.lastname: Fagerstedt
authors.forename: Silja
authors.initials: S
authors.lastname: Home
mesh_terms: D000426:Alcohol Dehydrogenase / Q000378:metabolism; D002523:Edible Grain; D005511:Food Handling / Q000379:methods*; D018525:Germination / Q000187:drug effects; D001467:Hordeum / Q000196:embryology*; D007700:Kinetics; D009584:Nitrogen / Q000008:administration & dosage; D010100:Oxygen / Q000008:administration & dosage*; D012639:Seeds / Q000254:growth & development*; D014835:Volatilization; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D000426:Alcohol Dehydrogenase; D000516:alpha-Amylases; D009584:Nitrogen; D010100:Oxygen