Edyta Kordialik-Bogacka

Antiradical and Reducing Potential of Commercial Beers

The antioxidant properties of commercial beers and their changes during storage were investigated. The relationship between the antioxidant capacity and total polyphenol contents of a range of commercial beers were evaluated. The results show that the antiradical and reducing potential varies depending on the type of beer and the processing steps involved in its production. Higher antiradical potential and polyphenol content in dark beers than in lager, dealcoholised and wheat beers were determined. A strong relationship was found between the total polyphenol content and both antiradical activity and reducing power, as measured by DPPH and FRAP assays. When any decrease in antioxidant activity as a result of storage was observed, it occurred mainly after the initial 4-week storage period. The total polyphenol content dropped more sharply than the antiradical and reducing ability over the same time periods.

Metal uptake capacity of modified Saccharomyces pastorianus biomass from different types of solution

In this paper, we investigate the effect of different biomass pretreatments on metal ion uptake by various biosorbents. Heat-treated as well as caustic-treated and ground biomass of Saccharomyces pastorianus was used to remove copper, lead and cadmium from various solutions. Untreated yeast was used as the control sample. The effect of yeast modification on sorption capacity depended on the different types of heavy metal ions and whether they were in single- or multi-component solutions. The highest uptake of copper and lead from a single-metal solution was obtained from heat-treated cells. Ground biomass was the most efficient at cadmium removal. However, the sorption capacity of the modified biomass did not improve when metal ions were removed from multi-component solutions. Indeed, the results in this paper show that optimizing metal removal from single-cation solutions can lead to decreased sorption capacity in multi-component solutions. Therefore, while adjusting the procedure of biomass modification, not only the nature of the metal ion being sorbed but also the chemical composition of the metal ion solution should be taken into account.

Suitability of unmalted quinoa for beer production: Suitability of unmalted quinoa for beer production

BACKGROUND This study provides the first detailed investigation into the effect of partially substituting barley malt with quinoa (Chenopodium quinoa Willd.) on the characteristics of wort and beer. Quinoa seeds and flakes were compared in terms of their suitability for brewing. The benefits of applying a commercial enzyme mixture during beer production with quinoa were also investigated. RESULTS These findings show that quinoa is a good starchy raw material for brewing. Even without exogenous enzymes, it is possible to substitute barley malt with up to 30% quinoa. The form in which quinoa is used has a negligible influence on the quality of the wort and beer. The foam stability of beer made with quinoa was better than that of all-malt beer, despite there being a lower level of soluble nitrogen in quinoa beer in comparison with all-malt beer and more than twice the amount of fat in quinoa in comparison to barley malt. CONCLUSION The addition of unmalted quinoa does not give unpleasant characteristics to the beer and was even found to have a positive effect on its overall sensory quality. This offers brewers an opportunity to develop good beers with new sensory characteristics.