title: Effect of soy peptide on brewing beer.
abstract: Here, we examined the effect of soy peptides (SPs) on the fermentation and growth of Yeast Bank Weihenstephan 34/70 (W34/70), a bottom-fermenting yeast. We compared fermentation for SP with that for a free amino acid (FAA) mixture having the same amino acid composition as SP, as a nitrogen source. Maltose syrup was used as a carbon source, and the medium contained excess amounts of essential minerals and vitamins. We observed that SP was better than FAA mixture at promoting fermentation and growth and that much more beta-phenylethyl alcohol was produced during fermentation with SP than with FAA mixture. Subsequently, we compared fermentations with the FAA mixture and selected mixtures containing various dipeptides of Phe as a nitrogen source. We found that the rates of Phe metabolism and beta-phenylethyl alcohol generation were much higher when Phe was presented as a dipeptide (Phe-Asp, Phe-Leu, or Phe-Phe) than when presented as FAA. These results show that amino acids such as Phe are absorbed more rapidly when presented as a peptide than as FAA, resulting in a more rapid production of beta-phenylethyl alcohol.
authors.affiliation: Food Science Research Institute, Research & Development HQ, Fujioil Co., Ltd., 4-3 Kinunodai, Tsukubamirai, Ibaraki 300-2497, Japan. kitagawa.sayuri@so.fujioil.co.jp
authors.forename: Sayuri
authors.initials: S
authors.lastname: Kitagawa
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Mukai
authors.forename: Yuko
authors.initials: Y
authors.lastname: Furukawa
authors.forename: Kanako
authors.initials: K
authors.lastname: Adachi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Mizuno
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Iefuji
mesh_terms: D000596:Amino Acids / Q000494:pharmacology*; D001515:Beer; D004151:Dipeptides / Q000378:metabolism* / Q000494:pharmacology; D008320:Maltose / Q000494:pharmacology; D010626:Phenylethyl Alcohol / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000254:growth & development*; D030262:Soybean Proteins / Q000494:pharmacology*; D013549:Sweetening Agents / Q000494:pharmacology*
chemical_list: D000596:Amino Acids; D004151:Dipeptides; D030262:Soybean Proteins; D013549:Sweetening Agents; D008320:Maltose; D010626:Phenylethyl Alcohol