Polyclar® [PVPP] for improving shelf life in laboratory treated lagers

This study was undertaken to generate systematic treatment data (dose response) for colloidal stabilization enhancement (shelf life) of commercial beer when treated with Polyclar®. Samples of lager beers were treated with increasing dosages of two different forms of Polyclar® (Polyclar 10 and Super R.) at a contact time of a minimum of 15 minutes. Polyclar 10® is a nonregenerative version of cross linked polyvinyl pyrrolidone. Polyclar Super R® is a regenerative form of cross linked polyvinyl pyrrolidone. Both Polyclar 10® and Polyclar Super R® are insoluble adsorbents approved for the treatment of beverages. The following parameters were monitored for the samples of commercial beer tested before and after treatment: Total polyphenol, flavanoids, tannoids, ammonium sulfate titre, and reducing power. Aging test was performed to determine the predicted shelf life. Samples were stored at 37 deg. C for a period of six weeks. During this period total haze was monitored periodically at one week intervals. The results showed that all Polyclar® treatments enhanced shelf life of lager beers. Treatment with Polyclar 10 at higher doses produced significant enhancement of the computed shelf life (seven fold), whereas treatment with Super R at equivalent dose produced a four fold increase in predicted shelf life. Beer treated with Polyclar® at high dose removed up to 45% of the initial levels of total polyphenols and flavanoids. During the aging process, beers that had not been treated with Polyclar® showed a decrease in flavanoids and polyphenols. There was a corresponding increase in tannoids, and similarly an increase in the measured total haze. In contrast, beer treated with high dose Polyclar®, showed an insignificant change in the levels of polyphenols, flavanoids and tannoids from their initial values after treatment. A working model based on specific adsorption of polyphenols by Polyclar® is provided to explain the experimental results. The Polyclar® treatment can be optimized to suit pilot plant and commercial conditions for treatment of different types of beer for increased colloidal stabilization and shelf life.