The extract containing natural antioxidants was obtained from a
residual stream generated during a brewery cleaning process. During
storage of beer, colloidal haze can develop as a result of the formation
of complexes between polypeptides and polyphenols. The negative
impact of polyphenols on haze stability is minimized by using
polyvinylpolypyrrolidone resin (PVPP) in a clarification step that is
essential to improve beer stability and extend its shelf life. As a result
of this process, a PVPP sludge loaded with polyphenolic compounds is
obtained and then washed with a NaOH solution (2% w/w) at room
temperature. After the NaOH-PVPP was filtered, a clean PVPP resin
and a PVPP washing solution (PVPP-WS) containing phenolic compounds
were obtained.