Brewing with malted barley or raw barley: what makes the difference in the processes?

Comparative analysis of malt quality and starch characteristics of three South Korean barley cultivars

In this study, malt was produced in pilot-scale facilities and conditioned using three barley (Hordeum vulgare L.) cultivars in South Korea (Heugho, Hopum, and Kwangmaeg). Quality and starch characteristics were compared. The starch content was considerably reduced in all malts. Coleoptile elongation was higher in Heugho (HHM; 85.7% ± 12.6%) and Hopum (HPM; 83.9% ± 10.7%) than in Kwangmaeg (KMM; 78.1% ± 9.9%) malt. Malt yield ranged from 81.8 to 84.9%, with no significant difference. All samples presented type A crystallinity, and granules showed discoid shapes. After malting, the mono- and di-saccharide contents (not including sucrose) were increased. The fermentable sugar level was the highest in HHM, whereas non-fermentable sugar was the highest in KMM. These results suggest that HPM enables efficient scarification based on the rapid degradation of starch, while Heugho barley and HHM have a high potential for beer and malt production, respectively.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01419-6.

Modeling and Optimization of Triticale Wort Production Using an Artificial Neural Network and a Genetic Algorithm

Triticale grain, a wheat-rye hybrid, has been reported to comply very well with the requirements for modern brewing adjuncts. In this study, two triticale varieties, in both unmalted and malted forms, were investigated at various ratios in the grist, applying different mashing regimes and concentrations of the commercial enzyme Shearzyme® 500 L with the aim of evaluating their impact on wort production. In order to capture the complex relationships between the input (triticale ratio, enzyme ratio, mashing regime, and triticale variety) and output variables (wort extract content, wort viscosity, and free amino nitrogen (FAN) content in wort), the study aimed to implement the use of artificial neural networks (ANNs) to model the mashing process. Also, a genetic algorithm (GA) was integrated to minimize a specified multi-objective function, optimizing the mashing process represented by the ANN model. Among the solutions on the Pareto front, one notable set of solutions was found with objective function values of 0.0949, 0.0131, and 1.6812 for the three conflicting objectives, respectively. These values represent a trade-off that optimally balances the different aspects of the optimization problem. The optimized input variables had values of 23%, 9%, 1, and 3 for the respective input variables of triticale ratio, enzyme ratio, mashing regime, and triticale variety. The results derived from the ANN model, applying the GA-optimized input values, were 8.65% w/w for wort extract content, 1.52 mPa·s for wort viscosity, and 148.32 mg/L for FAN content in wort. Comparatively, the results conducted from the real laboratory mashing were 8.63% w/w for wort extract content, 1.51 mPa·s for wort viscosity, and 148.88 mg/L for FAN content in wort applying same input values. The presented data from the optimization process using the GA and the subsequent experimental verification on the real mashing process have demonstrated the practical applicability of the proposed approach which confirms the potential to enhance the quality and efficiency of triticale wort production.

Delineation of Genotype X Environment Interaction for Grain Yield in Spring Barley under Untreated and Fungicide-Treated Environments

Barley (Hordeul vulgare L.) is the fourth most important cereal crop based on production and cultivated area. Biotic stresses, especially fungal diseases in barley, are devastating, incurring high possibilities of absolute yield loss. Identifying superior and stable yielding genotypes is crucial for accompanying the increasing barley demand. However, the identification and recommendation of superior genotypes is challenging due to the interaction between genotype and environment. Hence, the present investigation was aimed at evaluating the grain yield of different sets of spring barley genotypes when undergoing one of two treatments (no treatment and fungicide treatment) laid out in an alpha lattice design in six to seven locations for five years, through additive main effects and multiplicative interaction (AMMI), GGE biplot (genotype + genotype X environment), and stability analysis. The combined analysis of variance indicated that the environment was the main factor that contributed to the variation in grain yield, followed by genotype X environment interaction (GEI) effects and genotypic effects. Ten mega environments (MEs) with five MEs from each of the treatments harboured well-adapted, stable yielding genotypes. Exploiting the stable yielding genotypes with discreet use of the representative and discriminative environments identified in the present study could aid in breeding for the improvement of grain yield in spring barley genotypes.

A Highly Sensitive Method for the Detection of Hydrolyzed Gluten in Beer Samples Using LFIA

Most gluten analysis methods have been developed to detect intact gluten, but they have shown limitations in certain foods and beverages in which gluten proteins are hydrolyzed. Methods based on G12/A1 moAbs detect the sequences of gluten immunogenic peptides (GIP), which are the main contributors to the immune response of celiac disease (CD). Immunogenic sequences with tandem epitopes for G12/A1 have been found in beers with <20 mg/kg gluten, which could be consumed by CD patients according to the Codex Alimentarius. Therefore, an accurate method for the estimation of the immunogenicity of a beer is to use two moAbs that can recognize celiac T cell epitopes comprising most of the immunogenic response. Here, a specific and sensitive method based on G12/A1 LFIA was developed to detect GIP in beers labeled gluten-free or with low gluten content, with an LOD of 0.5 mg/kg. A total of 107 beers were analyzed, of those 6.5% showed levels higher than 20 mg/kg gluten and 29% showed levels above the LOD. In addition, G12/A1 LFIA detected gluten in 15 more beer samples than competitive ELISA with another antibody. Despite their labeling, these beers contained GIP which may cause symptoms and/or intestinal damage in CD patients.

From the Raw Materials to the Bottled Product: Influence of the Entire Production Process on the Organoleptic Profile of Industrial Beers

In the past few years, there has been a growing demand by consumers for more complex beers with distinctive organoleptic profiles. The yeast, raw material (barley or other cereals), hops, and water used add to the major processing stages involved in the brewing process, including malting, mashing, boiling, fermentation, and aging, to significantly determine the sensory profile of the final product. Recent literature on this subject has paid special attention to the impact attributable to the processing conditions and to the fermentation yeast strains used on the aromatic compounds that are found in consumer-ready beers. However, no review papers are available on the specific influence of each of the factors that may affect beer organoleptic characteristics. This review, therefore, focuses on the effect that raw material, as well as the rest of the processes other than alcoholic fermentation, have on the organoleptic profile of beers. Such effect may alter beer aromatic compounds, foaming head, taste, or mouthfeel, among other things. Moreover, the presence of spoilage microorganisms that might lead to consumers’ rejection because of their impact on the beers’ sensory properties has also been investigated.

Optimisation of Malting Parameters for Quinoa and Barley: Application of Response Surface Methodology

Quinoa (Chenopodium quinoa Willd) is a nutritious pseudocereal that is more stress-tolerant compared with traditional cereals. It is an excellent example of a climate-smart crop that is more resilient to climate change compared with barley. The purpose of the study was to investigate the optimum malting conditions required to produce quinoa malt using barley as a control. Response surface methodology (RSM) was used to investigate the influence of the two malting parameters steeping time and germination time on Brix (wort extract), diastatic power (DP), and free amino nitrogen (FAN) of the malt. The temperature was set at 15°C during the steeping process. Steeping time ranging from 12 to 48 hours and germination time ranging from 24 to 96 hours were designed using a central composite design (CCD). The kilning temperature for all malts was 65°C. For quinoa malt, there was a notable weak positive correlation between germination time and Brix (r = +0.119). However, there was a strong positive correlation between steeping time and diastatic power (r = +0.893). A similar trend was noted for barley with a weak positive correlation between germination time and Brix (r = +0.142). A strong positive correlation was also recorded between steeping time and diastatic power (r = +0.897) during the malting of barley. There was a relatively stronger correlation between steeping time and FAN (r = +0.895) than germination time and FAN (r = +0.275) in quinoa malt. The optimum values for the malting of barley were 47.68 hrs steeping time and 82.55 hrs germination time with a desirability value of 1.00. The responses for the optimised barley malt were 8.25°Bx, 162.28 mg/L, and 271.69°L for Brix, FAN, and diastatic power, respectively. To produce quinoa malt with Brix, FAN, and diastatic power of 8.37°Bx, 165.60 mg/L, and 275.86°L, respectively, malting conditions of 47.69 hrs steeping time and 95.81 hrs germination time are required. It was noted that quinoa is a very good candidate for producing high-quality malt for the brewing process.

Quality and Pro-Healthy Properties of Belgian Witbier-Style Beers Relative to the Cultivar of Winter Wheat and Raw Materials Used

Unmalted wheat grain and barley malt are the basic materials used in the production of Belgian wheat beers known as Witbier. A change in the ingredients defined in the recipe, by which part of the unmalted wheat is replaced with wheat malt, can positively affect the quality of the beverage produced. The purpose of the study was to brew Witbier-style beers made from four cultivars of winter wheat, with a 50% share of unmalted wheat and barley malt as well as Witbier-style beers made from four wheat cultivars, where 25% of unmalted wheat was replaced with wheat malt. Physicochemical and sensory analyzes showed mild differences in the quality of the beer products, more specifically higher alcohol content (by 11.33%) were found in beers made without the addition of wheat malt, while higher sensory attractiveness and 17.13% higher total polyphenol content were identified in beers enhanced with wheat malt. Phenolic compounds were identified using UPLC-PDA-MS/MS. The highest flavanol content, including kaempferol 3-O-rhamnoside-7-O-pentoside, was found in beers produced using wheat grains of the ‘Elixer’ cultivar, whether or not wheat malt was added; the values were 1.31 mg/L in E50 beer, and 1.39 mg/L in E25 beer. The same beer samples with the highest antioxidant and antiradical activity were found (in E25 beer, 2.35 mmol TE/L, and in E50 beer, 2.12 mmol Fe^2+/L). The present findings show that the investigated wheat cultivars may be used in beer production, whereas replacing part of unmalted wheat with wheat malt can improve the sensory profile of the beer produced.

Constant temperature mashing at 72 °C for the production of beers with a reduced alcohol content in micro brewing systems

In this paper, we present a constant temperature mashing procedure where grist made of Pilsner malt is mashed-in directly in the temperature regime of alpha-amylase activity, thus omitting all conventional steps, followed by constant temperature mashing at 72 °C. The aim was to investigate an alternative mashing procedure for the production of alcohol-reduced beers. The mashing proceeds with a rapid buildup of sugars and is completed after 120 min at the latest, giving an iodine normal and clear wort. However, the distribution of the different sugars in the worts is strongly altered, in comparison to a more classical mashing procedure. The free amino nitrogen (FAN) concentration is sufficient for vivid fermentation with the bottom fermenting yeast Saccharomyces pastorianus TUM 34/70. The lag phase and initial fermentation performance of this yeast strain are comparable for conventionally and isothermally (72 °C) mashed wort. Under the given conditions the fermentation of the isothermally (72 °C) made wort is finished after 6 days whereas a conventional wort needs 4–5 days more to be completed. The alcohol concentration is remarkably reduced by isothermal mashing leading to roughly 3.4 vol.-% with an original gravity of 11°P whereas with a conventional mashing procedure 4.4 vol.-% are obtained for the same original gravity. In both cases the concentrations of the fermentation by-products are comparable. A preliminary comparison of taste and foam stability did not show striking differences. Constant temperature mashing at 72 °C is a simple way to reduce the alcohol content of beer enriching it at the same time with non-fermentable sugars.

Buckwheat and Amaranth as Raw Materials for Brewing, a Review

Globally, beer is considered the most-consumed low-alcohol beverage, it ranks third, after water and tea, in the top sales of these drinks. New types of beer are the result of the influence of several factors, including innovations in science and technology, changing requirements for food consumption of the population, competition between producers, promotion of food for health, flavor, and quality, the limited nature of traditional food resource raw materials, and the interest of producers in reducing production costs. Manufacturers are looking for new solutions for obtaining products that meet the requirements of consumers, authentic products of superior quality, with distinctive taste and aroma. This review proposes the use of two pseudocereals as raw materials in the manufacture of beer: buckwheat and amaranth, focusing on the characteristics that recommend them in this regard. Due to their functional and nutraceutical properties, these pseudocereals can improve the quality of beer-a finished product. Additionally, all types of beer obtained from these pseudocereals are recommended for diets with particular nutritional requirements, especially gluten-free diets. Researchers and producers will continue to improve and optimize the sensory and technological properties of the new types of beer obtained from these pseudocereals.

Quality attributes for barley malt: "The backbone of beer"

Malting is the process of preparing barley for brewing through partial germination followed by drying. This process softens the grain cell wall and stimulates the production of diastatic enzymes, which convert starch into malt extract. The suitability of a barley grain for malt production depends upon a large number of quality parameters that are crucial for the identification and release of high-quality malt varieties. Maintaining tight control of these quality attributes is essential to ensure high processing efficiency and final product quality in brewery and malt house. Therefore, we have summarized the basic malting process and various physiological and biochemical quality parameters that are desirable for better malt quality. This study may provide an understanding of the process, problems faced, and opportunities to maltsters and researchers to improve the malt efficiency by altering the malting process or malt varieties.

Gluten Assessment in Beers: Comparison by Different Commercial ELISA Kits and Evaluation of NIR Analysis as a Complementary Technique

Traditionally, beers are made with gluten-containing cereals. It is crucial to have rapid analytical methodologies that allow gluten content control of the beers for celiac consumers. We assess the content of gluten in 65 conventional and 41 gluten-free labeled beers commercialized in Europe and compare the results in a subgroup of 71 beers with three ELISA kits. This research allows gathering information on the potential complementary utility of NIR analysis applied to gluten analysis of gluten-free beers in terms of time saving. Results obtained with the ELISA technique identified competitive R5 to be the most sensitive in detecting the prolamins, by eliciting a higher number of beers containing gluten above 20 mg/kg. The gluten content in conventional beers tested increased with the presence of wheat as raw material and with the use of ale-type yeasts. By using competitive R5, 3 out of the 41 gluten-free labeled beers appeared to contain gluten above 20 mg/kg, and conversely, 15 out of 65 of the conventional beers showed a gluten content below this threshold. According to our approaches, NIR did not achieve a suitable correlation with ELISA results, neither for gluten quantification nor for discrimination, and therefore, it cannot be proposed as a complementary technique.

Characteristics of the Proteolytic Enzymes Produced by Lactic Acid Bacteria

Over the past several decades, we have observed a very rapid development in the biotechnological use of lactic acid bacteria (LAB) in various branches of the food industry. All such areas of activity of these bacteria are very important and promise enormous economic and industrial successes. LAB are a numerous group of microorganisms that have the ability to ferment sugars into lactic acid and to produce proteolytic enzymes. LAB proteolytic enzymes play an important role in supplying cells with the nitrogen compounds necessary for their growth. Their nutritional requirements in this regard are very high. Lactic acid bacteria require many free amino acids to grow. The available amount of such compounds in the natural environment is usually small, hence the main function of these enzymes is the hydrolysis of proteins to components absorbed by bacterial cells. Enzymes are synthesized inside bacterial cells and are mostly secreted outside the cell. This type of proteinase remains linked to the cell wall structure by covalent bonds. Thanks to advances in enzymology, it is possible to obtain and design new enzymes and their preparations that can be widely used in various biotechnological processes. This article characterizes the proteolytic activity, describes LAB nitrogen metabolism and details the characteristics of the peptide transport system. Potential applications of proteolytic enzymes in many industries are also presented, including the food industry.

Optimization of Beer Brewing by Monitoring α-Amylase and β-Amylase Activities during Mashing

(1) Background: In the current highly competitive brewing industry, most breweries may benefit from a reduction in mashing time. In this study, a novel enzymatic assay format was used to investigate the activities of α-amylase and β-amylase during different mashing profiles, with the aim to use it as a tool for optimizing the production time of an existing industrial mashing process; (2) Methods: Lab-scale mashings with eight different time-temperature programs and two different pilot brews were analyzed in terms of enzymatic activity, sugar composition, alcohol by volume in the final beer, FAN and others; (3) Results: A 20-min reduction (out of an original 73-min mashing program) was achieved by selecting a temperature profile which maintained a higher enzymatic activity than the original, without affecting the wort sugar composition and fermentability, or the ethanol concentration and foam stability of the final beer. (4) Conclusions: A method is presented which can be used by breweries to optimize their mashing profiles based on monitoring α-amylase and β-amylase activities.

Brewing with Unmalted Cereal Adjuncts: Sensory and Analytical Impacts on Beer Quality

Brewing with unmalted cereal adjuncts can reduce the requirement for malting, thereby lowering costs and improving the overall sustainability of the brewing chain. However, substantial adjunct usage has technological challenges and the sensory characteristics of beers produced using high adjunct rates are still not fully understood. This study examined the impacts of brewing with unmalted barley, wheat, rice and maize at relatively high concentrations (0, 30% and 60% of grist) on the sensorial and analytical profiles of lager beer. Adjunct based beers and a 100% malt control were brewed at 25 L scale. A trained sensory panel (n = 8) developed a lexicon and determined the sensorial profile of beers. At 30% adjunct incorporation there was insignificant variation in the expected beer flavour profile. At 60% adjunct incorporation, there were some significant sensory differences between beers which were specific to particular adjunct materials. Furthermore, 60% adjunct inclusion (with correspondingly low wort FAN) impacted the fermentation volatile profile of the final beers which corresponded with findings observed in the sensory analysis. Developing an understanding of adjunct-induced flavour differences and determining strategies to minimise these differences will facilitate the implementation of cost-efficient and sustainable grist solutions.

Diversity and dynamics of sourdough lactic acid bacteriota created by a slow food fermentation system

Sourdough is a naturally fermented dough that is used worldwide to produce a variety of baked foods. Various lactic acid bacteria (LAB), which can determine the quality of sourdough baked foods by producing metabolites, have been found in the sourdough ecosystem. However, spontaneous fermentation of sourdough leads to unpredictable growth of various micro-organisms, which result in unstable product quality. From an ecological perspective, many researchers have recently studied sourdough LAB diversity, particularly the elucidation of LAB community interactions and the dynamic mechanisms during the fermentation process, in response to requests for the control and design of a desired sourdough microbial community. This article reviews recent advances in the study of sourdough LAB diversity and its dynamics in association with unique characteristics of the fermentation system; it also discusses future perspectives for better understanding of the complex sourdough microbial ecosystem, which can be attained efficiently by both in vitro and in situ experimental approaches.

Barley α-amylase/subtilisin inhibitor shows inhibitory activity against endogenous xylanase isozyme I of malted barley: A novel protein function

Mashing process had little influence on the arabinoxylan content in the finished wort. In this paper, a protein with inhibitory activity against the endogenous xylanase isozyme I (X-I) of malted barley was extracted and purified using a combination of ion-exchange and size-exclusion chromatography. The protein was identified as barley α-amylase/subtilisin inhibitor (BASI). According to the amino acid sequence analysis, BASI was completely different from the previous reported xylanase inhibitors. BASI showed dosage-dependent inhibitory activity. BASI exhibited a maximum inhibitory activity at 50°C and pH 6.0. BASI inhibited X-I as a competitive manner. PRACTICAL APPLICATIONS: A protein with inhibitory activity against the major endogenous xylanase isozyme I (X-I) of malted barley was extracted, purified, and characterized, which was identified as barley α-amylase/subtilisin inhibitor (BASI). The results help brewers to achieve a better understanding of the mechanism of arabinoxylan degradation during mashing. BASI can be used as an indicator to screen microbial xylanases. The microbial xylanases insensitive to BASI would have obvious advantages in the degradation of arabinoxylan polymers and filterability improvement during mashing.

Insights on the Proteases Involved in Barley and Wheat Grain Germination

Seed storage proteins must be hydrolyzed by proteases to deliver the amino acids essential for embryo growth and development. Several groups of proteases involved in this process have been identified in both the monocot and the dicot species. This review focuses on the implication of proteases during germination in two cereal species, barley and wheat, where proteolytic control during the germination process has considerable economic importance. Formerly, the participation of proteases during grain germination was inferred from reports of proteolytic activities, the expression of individual genes, or the presence of individual proteins and showed a prominent role for papain-like and legumain-like cysteine proteases and for serine carboxypeptidases. Nowadays, the development of new technologies and the release of the genomic sequences of wheat and barley have permitted the application of genome-scale approaches, such as those used in functional genomics and proteomics. Using these approaches, the repertoire of proteases known to be involved in germination has increased and includes members of distinct protease families. The development of novel techniques based on shotgun proteomics, activity-based protein profiling, and comparative and structural genomics will help to achieve a general view of the proteolytic process during germination.