title: Foam-stabilizing effects and cling formation patterns of iso-alpha-acids and reduced iso-alpha-acids in lager beer.
abstract: Foam-stabilizing properties and cling formation patterns of iso-alpha-acids and reduced iso-alpha-acids were investigated using an unhopped lager beer. Unhopped beer was dosed with iso-alpha-acid (Iso), rho-iso-alpha-acid (Rho), tetrahydro-iso-alpha-acid (Tetra), and hexahydro-iso-alpha-acid (Hexa), separately, over a range of concentrations from 2 to 10 ppm. A uniform foam was created by Inpack 2000 Flasher Head and was measured by a NIBEM Foam Stability Tester (NIBEM-TPH) followed by a NIBEM Cling Meter (NIBEM-CLM) to determine the relationship between the concentration and NIBEM-30 and the cling formation ability of each compound. The foam-stabilizing power was determined to be Tetra, Hexa, Iso, and Rho from the strongest to weakest. Linear regression models were created using the NIBEM-TPH data set, and on the basis of 95% confidence intervals, the foam stability of Tetra or Hexa became significantly larger than that of Iso when 2.4 or 4.2 ppm of Tetra or Hexa was used as a replacement for Iso, respectively. Cling formation patterns could be categorized into three groups: "ring", "mesh", and "powdery". The control beer had the lowest foam stability and did not yield any foam cling.
authors: Department of Food Science and Technology, Oregon State University, 100 Wiegand Hall, Corvallis, Oregon 97331, USA.
authors: Takeshi
authors: T
authors: Kunimune
authors: Thomas H
authors: TH
authors: Shellhammer
mesh_terms: D001515:Beer / Q000032:analysis*; D003517:Cyclopentanes / Q000032:analysis / Q000737:chemistry*; D005524:Food Technology / Q000379:methods*; D001467:Hordeum / Q000737:chemistry; D027582:Humulus / Q000737:chemistry; D006865:Hydrogenation; D016014:Linear Models; D009812:Odorants / Q000032:analysis; D010940:Plant Proteins / Q000032:analysis
chemical_list: D003517:Cyclopentanes; D010940:Plant Proteins