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.

In this study 40 Hungarian retail beers were evaluated for folic acid content, antioxidant profile and physicochemical parameters. The physicochemical parameters, folic acid content and antioxidant activity of alcohol-free beers were the lowest. Folic acid content of beers aged with sour cherries showed high values, more than 0.4 mg/l and an alcohol-free beer-based mixed drink made with lemon juice contained more than 0.2 mg/l of folic acid. Dark beers and beers aged with sour cherries had the highest antioxidant activity probably owing to their high extract content, components released from the fruits and special malts. These results highlight the possibility of achieving adequate folic acid and relevant antioxidant intake without excessive alcohol and energy consumption by selecting appropriate beer types.

In this study, 13 properties (alcohol‐, real extract‐, flavonoid‐, anthocyanin, glucose, fructose, maltose, sucrose content, EBC [European Brewery Convention] and L*a*b* color, bitterness) of 21 beers (alcohol‐free pale lagers, alcohol‐free beer‐based mixed drinks, beer‐based mixed drinks, international lagers, wheat beers, stouts, fruit beers) were determined. In the first step, multiple factor analysis (MFA) was performed for the whole data and five clusters (target classes) were determined; then, a bootstrapping was applied to establish a balanced data so as every cluster should contain 100 samples and the total sample size is 500. In the second step, 12 supervised learning algorithms (random trees [RND], Quinlan's C4.5 decision tree algorithm [C4.5], Iterative Dichotomiser 3 algorithm [ID3], cost‐sensitive decision tree algorithm [CSMC4], cost‐sensitive classification tree [CSCRT], k‐nearest neighbors algorithm [KNN], radial basis function [RBF], multilayer perceptron neural network [MLP], prototype nearest neighbor [PNN], linear discriminant analysis [LDA], naïve Bayes with continuous variables [NBC], partial least squares discriminant analysis [PLS‐DA]) were applied to classify each brand into the target classes. Furthermore, several error rates were calculated: re‐substitution error rate (RER), cross‐validated error rate (CV), bootsrap error (BOOT), leave‐one‐out (LOO), and train‐test error rate (TRAIN). The MFA could discriminate five groups, which can be characterized by some analytical parameters, and the other multivariate methods performed similarly. The methods can be discriminated best based on the BOOT, CV, and LOO. The best estimation methods are the C4.5, CSMC4, and CSCRT; these performed best along the flavonoid content and EBC color. It identified that the methods most sensitive to the properties are the NBC. The classification ability fluctuated greatly in the case of three properties (glucose, maltose, sucrose). A remarkable fluctuation has been experienced in the case of L*a*b* color parameters, flavonoid content, EBC color, and bitterness by NBC method.