Maiorca wheat malt: A comprehensive analysis of physicochemical properties, volatile compounds, and sensory evaluation in brewing process and final product quality

This study explores the potential of Maiorca wheat malt as an alternative ingredient in beer production, investigating its impact on the brewing process and beer quality at different recipe contents (50 %, 75 %, 100 %). The study encompasses a comprehensive analysis of key malt parameters, revealing Maiorca malt's positive influence on maltose, glucose, filterability, extract, free amino nitrogen, and fermentability. Notably, the malt exhibited heightened levels of α-amylase and β-amylase enzymes compared to conventional commercial malt. Furthermore, the analysis of aroma compounds and subsequent sensory evaluations unveiled a significant correlation between the proportion of Maiorca malt in the formulation and intensified estery, fruity, malty, honey, complemented by a reduction in attributes such as aromatic compounds, phenolic, yeasty, sulfury, oxidized, and solvent-like odors. This research underscores the favorable contribution of Maiorca wheat malt to enhancing both the brewing process and final beer quality, highlighting its potential as an innovative ingredient in brewing practices.

Flavour Stability of a Cold-Stored Unpasteurized Low-Alcohol Beer Produced by Saccharomycodes ludwigii

Low-alcohol beer (LAB) is a growing part of the brewing industry in terms of market volumes and consumer interest. Universities and research centres are making efforts to improve organoleptic profile and flavour stability of the product. One of the main limitations of such products is the stability. These beers must be severely filtered and pasteurized, causing a significant loss of quality in terms of flavour. Herein, flavour stability of an unpasteurized and unfiltered LAB was checked during 120 days of cold storage (4 ± 1 °C). The results showed that the beer remained stable for 120 days for many observed parameters. The alcohol content increased from 0.5 to 0.7% v/v. The beer without oxygen was more stable than that filled with oxygen in the headspace. The results confirmed the possibility to produce an unpasteurized craft LAB by Saccharomycodes ludwigii by the cold chain.

Graphical Abstract

Complementing Digital Image Analysis and Laser Distance Meter in Beer Foam Stability Determination

The aim of this research is to investigate the possibility of applying a laser distance meter (LDM) as a complementary measurement method to image analysis during beer foam stability monitoring. The basic optical property of foam, i.e., its high reflectivity, is the main reason for using LDM. LDM measurements provide relatively precise information on foam height, even in the presence of lacing, and provide information as to when foam is no longer visible on the surface of the beer. Sixteen different commercially available lager beers were subjected to analysis. A camera and LDM display recorded the foam behavior; the LDM display which was placed close to the monitored beer glass. Measurements obtained by the image analysis of videos provided by the visual camera were comparable to those obtained independently by LDM. However, due to lacing, image analysis could not accurately detect foam disappearance. On the other hand, LDM measurements accurately detected the moment of foam disappearance since the measurements would have significantly higher values due to multiple reflections in the glass.

Relationship between the index of protein modification (Kolbach index) and degradation of macromolecules in wheat malt

Kolbach index (KI) is an important index to evaluate the qualities of malt, which will affect protein molecular composition, enzyme activity, and other macromolecules degradation during wheat malting. In this paper, the relationship between wheat (Triticum aestivum L.) malts KI and the (i) characterization of albumins, globulins, gliadins, and glutenins and their hydrolysis and (ii) the enzymatic breakdown of starch and arabinoxylans during malting were studied. As malt KI values increased, all fractions of glutenins and gliadins were extensively hydrolyzed. The higher Mw globulins (36.6 to 70.8 kDa) were also increasingly degraded at higher KI values, but the concentration of smaller globulin fractions (14.9 to 35.0 kDa) had increased significantly. As for albumins, although their overall concentration had increased as KI increased, changes in the concentration of individual albumin fractions was more complex. While there were significant increases in the concentration of some new albumin proteins (43.8 and 84.4 kDa), the concentration of some albumins decreased (21.1 to 64.3 kDa), and some fractions had completely disappeared (28.8 and 64.3 kDa). Following mashing, the hydrophobicity of the worts had decreased significantly at higher KI values. At malt KI values between 39.5% and 42.7%, the enzymatic activity was at its highest, the degradation of starch was adequate and stable, and the concentration of water-soluble arabinoxylans was optimal. A KI value of about 39.5% to 42.7% was therefore considered optimal for the production of wheat malts with superior quality attributes. PRACTICAL APPLICATION: The findings from this study will be valuable to beer companies; a more precise control of the malting and brewing parameters, fundamental for the production of high-quality wheat malts and wheat beer, can be achieved.

Determination of Foam Stability in Lager Beers Using Digital Image Analysis of Images Obtained Using RGB and 3D Cameras

Foam stability and retention is an important indicator of beer quality and freshness. A full, white head of foam with nicely distributed small bubbles of CO2 is appealing to the consumers and the crown of the production process. However, raw materials, production process, packaging, transportation, and storage have a big impact on foam stability, which marks foam stability monitoring during all these stages, from production to consumer, as very important. Beer foam stability is expressed as a change of foam height over a certain period. This research aimed to monitor the foam stability of lager beers using image analysis methods on two different types of recordings: RGB and depth videos. Sixteen different commercially available lager beers were subjected to analysis. The automated image analysis method based only on the analysis of RGB video images proved to be inapplicable in real conditions due to problems such as reflection of light through glass, autofocus, and beer lacing/clinging, which make it impossible to accurately detect the actual height of the foam. A solution to this problem, representing a unique contribution, was found by introducing the use of a 3D camera in estimating foam stability. According to the results, automated analysis of depth images obtained from a 3D camera proved to be a suitable, objective, repeatable, reliable, and sufficiently sensitive method for measuring foam stability of lager beers. The applied model proved to be suitable for predicting changes in foam retention of lager beers.

Factors influencing the choice of beer: A review

Research on those variables that have been shown to influence the consumer's choice of beer is reviewed. The focus is on the choice of whether to drink beer as opposed to a beverage from another category, and to a greater extent, the choice between different types or styles of beer. Inspired by previous research on a diverse array of factors that have been shown to influence food and beverage choice, the review examines how beer choice is driven by consumer variables (covering biological, psychological, and socio-cultural factors), product-intrinsic attributes (the sensory aspects of the beer itself), product-extrinsic attributes (external sensory characteristics, such as packaging), and contextual and environmental influences. These situational factors refer to variables such as the location where choice/consumption takes place (i.e., on- versus off-trade), as well as the context, occasion, and reason for drinking. Current trends related to choice and consumption, such as the emerging interest in beer-food pairing, are also examined. The review groups these attributes which affect people's beer wanting, choice, and purchase in order to understand the beer consumer's choice process. Along with general conclusions, a number of key directions for future research are also presented, given that the relative contribution of each type of factor on consumer's choice behaviour is still unclear.

Development of a Rapid Method to Assess Beer Foamability Based on Relative Protein Content Using RoboBEER and Machine Learning Modeling

Foam-related parameters are associated with beer quality and dependent, among others, on the protein content. This study aimed to develop a machine learning (ML) model to predict the pattern and presence of 54 proteins. Triplicates of 24 beer samples were analyzed through proteomics. Furthermore, samples were analyzed using the RoboBEER to evaluate 15 physical parameters (color, foam, and bubbles), and a portable near-infrared (NIR) device. Proteins were grouped according to their molecular weight (MW), and a matrix was developed to assess only the significant correlations (p < 0.05) with the physical parameters. Two ML models were developed using the NIR (Model 1), and RoboBEER (Model 2) data as inputs to predict the relative quantification of 54 proteins. Proteins in the 0–20 kDa group were negatively correlated with the maximum volume of foam (MaxVol; r = −0.57) and total lifetime of foam (TLTF; r = −0.58), while those within 20–40 kDa had a positive correlation with MaxVol (r = 0.47) and TLTF (r = 0.47). Model 1 was not as accurate (testing r = 0.68; overall r = 0.89) as Model 2 (testing r = 0.90; overall r = 0.93), which may serve as a reliable and affordable method to incorporate the relative quantification of important proteins to explain beer quality.

Screening of Polyphenols and Antioxidative Activity in Industrial Beers

Antioxidative molecules, such as polyphenols can preserve and prolong the freshness of packaged beers. The aim of this work was to assess the content of polyphenolic compounds (by Folin-Ciocalteu and standard European Brewery Convention method) in different types of industrially produced beers (lager, pilsner, black and dark), packaged in brown glass bottles. The results of this research indicate that there are significant changes in polyphenol concentrations in correlation with beer type. Polyphenolic content was highest in dark and black beers. Antioxidative activity was also more pronounced in dark and black beers. Most prominent phenolic acid in all samples was gallic acid. Two samples of dark and three samples of black beers had >10 mg/100 mL of this polyphenol, with maximal value of 14.22 mg/100 mL in sample CK (black beer). This would indicate that black beers are richer in polyphenolic content than the light (lager and pilsner) beers and the moderate consumption of such beer could contribute to the health of consumers.

The visual appearance of beer: A review concerning visually-determined expectations and their consequences for perception

This review critically evaluates the literature concerning the impact of visual appearance cues (including colour, foam, and cloudiness) on people's perception in the beer category. The authors assess both the sensory expectations that are elicited by the visual appearance of beer, and the extent to which those expectations carry-over to influence the actual tasting experience. Beer is a particularly intriguing category to study since the differing production rules in different countries mean that there is not always the same scope to modify the colour in order to meet perceived consumer demands. What is more, there is currently disagreement in the literature concerning the impact of beer colour and foam on people's expectations of beer prior to tasting, and their multisensory flavour perception on tasting. Given how much beer is consumed annually, it is surprising that more research has not been published that assesses the undoubtedly important role of visual appearance in this beverage category. Part of the reason for this may simply be that it is difficult to create consistent experimental stimuli given the rapid transition of the head of the beer post-serving.

Probing heat-stable water-soluble proteins from barley to malt and beer

Proteins determine the quality of barley in malting and brewing end-uses. In this regard, water-soluble barley proteins play a major role in the formation, stability, and texture of head foams. Our objective was to survey the barley seed proteins that could be involved in the foaming properties of beer. Therefore, two-dimensional (2-D) electrophoresis and mass spectrometry were combined to highlight the barley proteins that could resist the heating treatments occurring during malting and brewing processes. As expected, from barley to malt and to beer, most of the heat-stable proteins are disulfide-rich proteins, implicated in the defense of plants against their bio-aggressors, e.g., serpin-like chymotrypsin inhibitors (protein Z), amylase and amylase-protease inhibitors, and lipid transfer proteins (LTP1 and LTP2). For LTP1s, the complex pattern displayed in 2-D electrophoresis could be related to some chemical modifications already described elsewhere, such as acylation or glycation through Maillard reactions, which occur on malting. Our proteomics approach allowed the identification of the numerous proteins present in beer in addition to the major ones already described. The involvement of these proteins in the quality of beer foam can now be evaluated.