Mechanisms of Adsorbent Action in Beverage Stabilization

Unstabilized apple juice (unfermented cider clarified by centrifugation and filtration) was treated with various amounts of bentonite, silica gel, or polyvinylpolypyrrolidone (PVPP). The effectiveness of these adsorbents was assessed by measurements of haze-active (HA) protein and HA polyphenol. Bentonite was very effective in removing HA protein, taking out about ∼92% at the highest treatment level, while silica gel removed only ∼25%. Bentonite and silica gel had little effect on HA polyphenol. PVPP took out essentially all of the HA polyphenol at the highest treatment level and reduced HA protein somewhat. These results are quite different from those obtained previously with beer but can be explained by the large differences in protein to polyphenol ratio between the two beverages.