In this study the evolution of antioxidant activity was investigated during malting of different barley cultivars, and during the production of different types of beers on laboratory scale and in pilot brewery. Samples were taken at technologically important points of productions. Malts were produced from 3 spring and 3 winter barley cultivars. Two types of beers were brewed under laboratory conditions, and two in a pilot brewery. For the determination of antioxidant activity five commonly used assays were applied such as ABTS Radical Scavenging Activity, Cupric Reducing Antioxidant Capacity, DPPH Radical Scavenging Activity, Ferric Reducing Antioxidant Power and Total Polyphenol Content. Prior to malting it was observed that there are orders of magnitude differences between the antioxidant activities of the barley varieties. During malting, the biggest increase was noticed during steeping. Spring and winter cultivars showed similar trends during steeping and germination, but kilning had different effect on antioxidant activity of the varieties. The antioxidant activity of malts was always higher than the corresponding barleys. During the brewing process antioxidants were released to the highest extent during the early stages of mashing. Adequate sparging and hop boiling could further improve the antioxidant potential of the wort. Furthermore, differences between the equipment used for wort separation and hop boiling under laboratory conditions and in the pilot brewery had effect on antioxidant activity. In the course of malting and brewing by selecting the appropriate raw materials and technological parameters, the conditions for the release and retention of antioxidants can be optimized.

Beer color is an important sensory attribute, the first one that the consumer observes. There are two standard methods accepted for determining the color of these products, one related to the European Brewery Convention (EBC) and the other is the Standard Reference Method (SRM). Both methods are based on absorbance, but in case of the more and more popular fruit beers these methods give false result since these products appear in varied colors and have different spectra than regular beers. In this study 39 different types of beers were investigated, including fruit beers and beer based mixed drinks to compare their color in CIE 1976 L*a*b* color space, absorption-based colors and transmission spectra. DE* ab values of products with less than 5% EBC difference ranged from 4.5 to 17.4. There were magnitude differences in the transmission spectra of these products, fruit beers showed different tendencies due to the added fruit or fruit juice. The highest DE* ab value belonged to two traditional Weissbiers. Absorption-based methods are not able in many cases to differentiate between products which have nearly the same EBC or SRM color but visually are different. A multi-wavelength method would be reasonable to be developed for more objective and accurate beer color determination.

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The aim of this research was to study the effect of micro- and industrial scale malting on the folate content of barley. Two malting barley varieties (one spring and one winter) were studied, applying the same technology. Furthermore, a roasting experiment was carried out at given temperatures for different time periods. The total folate content was determined by microbiological method. The folate content of the barleys was between 10.1 and 23.4 µg/100 g dry matter. For micro- and industrial scale, malting folate content increased 6.5–8-fold and 4–7-fold, respectively, during the malting process. An unexpected result was observed during industrial malting: the folate content increased during kilning by 18–35%, unlike micro scale malting, where a 15–20% decrease was observed. Results obtained during roasting showed that folic acid content did not decrease when roasted for 20 min at 100 °C, but it decreased linearly with increasing temperature. Folate is completely degraded in 20 min at 200 °C. It can be stated that barley malt can serve as a relatively good source of folate, but barley variety and malting technology have significant impact on it.

There are numerous scientific publications about the folate content of several types of beers available in commercial trade, but there is limited information about the effect of raw materials and technological steps of brewing on folate content. In this study the aim was to investigate different raw materials and the evolution of folate content during laboratory and pilot scale brewing. For the determination of folate content of different malts, three types of barley malts (Pilsner, Caramel, and Coloring), wheat malt, rye malt, and oat malt were analysed. For the study of the evolution of folate content during the brewing process, worts were produced on laboratory and pilot scale. Among malts, Pilsner type barley malt had the highest folate content (44.7 μg/100 g d.m.). During brewing the protein rest seemed to dissolve the majority of the folate content, and with the increasing temperature of the β- and α-amylase rests there was a further dissolution. Filtration and sparging did not have negative effect on folate concentration related to the extract content of the wort. Hop boiling had no negative effect on folate content, folate seemed to be stable during the one-hour boiling. Natural folate of barley malt seemed to be stable through the technological steps of brewing, offering the possibility to produce a foodstuff with high natural folate content.