Filtration and use of silica hydro gel and polyvinylpolypyrrolidone for removal of haze-active proteins and polyphenols in beer

by Peterson, Sarah M.

Peterson Sarah M (Writer) (Last Name) (First) Initial Filtration and Use of Silica Hydrogel and Polyvinylpolypyrrolidone for Removal of Haze-Active Proteins and Polyphenols in Beer (Title of Thesis) Food and Nutritional Sciences (Graduate Major) Dr. Martin Ondrus May, 2003 108 (Research Advisor) (Month/Year) (No. of Pages) American Psychological Association, 5th edition (Manual Style) There are several different types of haze that can be found in beer, but they are all caused by different reactions in the beer. The basis of this study was chill haze. Chill haze is caused by weak hydrogen bonding and hydrophobic interactions of haze-active proteins and haze-active polyphenols that complex to form a haze in the beer. It is unknown if there is a difference in haze-active and non-haze-active molecules, but studies conclude that the haze-active proteins contain a significant amount of proline, where the non-active proteins do not contain proline. The protein-polyphenol complexes that are formed are insoluble in beer thus causing the beer to appear cloudy. Many consumers will not drink beer that is cloudy, assuming that it is a microbial contamination, but most beers are pasteurized thus eliminating microbial contamination. ii Silica hydrogel (SHG) and polyvinylpolypyrrolidone (PVPP) were used in five different combinations in the secondary filtration of beer to remove proteins and polyphenols. All other aspects of the brewing remained constant. Total polyphenols, total flavanoids, dissolved oxygen, initial haze, accelerated haze, and crude protein were measured in each variation. Based on the results of the project as well as the cost analysis of the silica hydrogel and polyvinylpolypyrrolidone it was determined that the combination of stabilizers that would decrease the amount of haze (with a reasonable increase in expense) in the product would be the combination of 15 lbs silica hydro gel per 100 barrels and 4 lbs polyvinylpolypyrrolidone per 100 barrels. iii