title: Fermentation performance of lager yeast in high gravity beer fermentations with different sugar supplementations.
abstract: The effects of glucose, sucrose and maltose supplementations on the fermentation performance and stress tolerance of lager yeast (Saccharomyces pastorianus) during high gravity (18°P) and very high gravity (24°P) fermentations were studied. Results showed that throughout 18°P wort fermentation, fermentation performance of lager yeast was significantly improved by glucose or sucrose supplementation, compared with maltose supplementation, especially for sucrose supplementation increasing wort fermentability and ethanol production by 6% and 8%, respectively. However, in the later stage of 24°P wort fermentation, fermentation performance of lager yeast was dramatically improved by maltose supplementation, which increased wort fermentability and ethanol production by 14% and 10%, respectively, compared with sucrose supplementation. Furthermore, higher HSP12 expression level and more intracellular trehalose accumulation in yeast cells were observed by maltose supplementation with increase of the wort gravity from 18°P to 24°P, indicating higher stress response of yeast cells. The excretion of Gly and Ala, and the absorption of Pro in the later stage of fermentation were promoted by maltose supplementation. In addition, with increase of the wort gravity from 18°P to 24°P, higher alcohols level was decreased with maltose supplementation, while esters formation was increased significantly with glucose supplementation. This study suggested that the choice of optimal fermentable sugars maintaining better fermentation performance of lager yeast should be based on not only strain specificity, but also wort gravity.
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, No. 22 Xinong Road, Yangling 712100, China.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Lei
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, No. 22 Xinong Road, Yangling 712100, China.
authors.forename: Huaide
authors.initials: H
authors.lastname: Xu
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, No. 22 Xinong Road, Yangling 712100, China.
authors.forename: Li
authors.initials: L
authors.lastname: Feng
authors.affiliation: School of Biological Engineering, Dalian Polytechnic University, No. 1 Qinggongyuan Road, Dalian 116034, China.
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Yu
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, No. 381 Wushan Road, Guangzhou 510640, China.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Zhao
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, No. 381 Wushan Road, Guangzhou 510640, China. Electronic address: femmzhao@scut.edu.cn.
authors.forename: Mouming
authors.initials: M
authors.lastname: Zhao
mesh_terms: D001515:Beer / Q000382:microbiology*; D050260:Carbohydrate Metabolism / Q000187:drug effects; D004952:Esters / Q000378:metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D018471:Hypergravity; D008320:Maltose / Q000378:metabolism / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D014199:Trehalose / Q000378:metabolism
chemical_list: D004952:Esters; D029701:Saccharomyces cerevisiae Proteins; D008320:Maltose; D014199:Trehalose; D005947:Glucose
keywords: Fermentable sugars; Fermentation performance; High gravity fermentation; Lager yeast; Stress tolerance