Arabinoxylan from non-malted cereals can act as mouthfeel contributor in beer

Arabinoxylans: A review on protocols for their recovery, functionalities and roles in food formulations

Arabinoxylans (AXs) are compounds with high nutritional value and applicability, including prebiotics or supplementary ingredients, in food manufacturing industries. Unfortunately, the recovery of AXs may require advanced separation and integrated strategies. Here, an analysis of the emerging techniques to extract AXs from cereals and their by-products is discussed. This review covers distinct methods implemented over the last 2-3 years, identifying that the type of method, extraction source, AX physicochemical properties and pre-treatment conditions are the main factors influencing the recovery yield. Alkaline extraction is among the most used methods nowadays, mostly due to its simplicity and high recovery yield. Concurrently, recovered AXs applied in food applications is timely reviewed, such as potential bread ingredient, prebiotic and as a wall material for probiotic encapsulation, in beer and non-alcoholic beverage manufacturing, complementary ingredient in bakery products and cookies, improvers in Chinese noodles, 3D food printing and designing of nanostructures for delivery platforms.

The Impact of 10 Unmalted Alternative Adjuncts on Wort Characteristics

Consumers are more than ever in search of novel and exciting beer choices, and brewers are, therefore, continuously experimenting to adapt their product portfolio. One interesting way to naturally incorporate novel flavors and tastes is by using alternative adjuncts, but this is not always an easy and straightforward process. In this study, a 40% unmalted alternative adjunct (einkorn, emmer, spelt, khorasan, quinoa, amaranth, buckwheat, sorghum, teff, and tritordeum) or reference (barley malt, unmalted barley, and unmalted wheat) was added to 60% barley malt, after which three different laboratory mashing processes (Congress mash, Congress mash with pre-gelatinization of the adjunct, and Evans mash) were performed, and their behavior during mashing and the resulting wort characteristics were investigated in detail. Overall, the extraction process of all 10 unmalted alternative adjuncts was not complete for all three laboratory mashing processes, whereby Congress mashing resulted in the highest extract and fastest filtration, whereas Evans mashing resulted in the lowest extract and slowest filtration. Pre-gelatinization of the unmalted was generally only beneficial for adjuncts with high onset starch gelatinization temperatures. This process also inactivated endogenous enzymes in the unmalted adjuncts, which had an adverse effect on the mashing process.

Advancing Quantification of Water-Extractable Arabinoxylan in Beer: A High-Throughput Approach

Water-extractable arabinoxylan (WEAX) may cause major problems during clarification processes in a brewery owing to its ability to form gel networks. However, high WEAX contents can also enhance the nutritional quality of the final product as they play an important role in the human diet. Therefore, precise quantification of WEAX is required. Current methods are very time- and resource-consuming as well as limited in the number of samples and in some cases provide low accuracy. Thus, a reproducible high-throughput method for the quantification of WEAX optimized for beer was developed, reaching recovery rates (RRs) of almost 100%. The assay is based on Douglas's colorimetric method. Hydrolysis was conducted using glacial acetic acid to induce the formation of red color complexes resulting from the interaction between pentose degradation products and phloroglucinol. The method was successfully transferred to a multi-mode microplate reader to minimize the loss of color intensity over time and to obtain a high throughput. By using 96-well plates, up to 40% of the previous analysis time could be saved, and a larger number of samples could be analyzed in one batch. The collected data determined xylose as an optimal calibration standard due to high accuracy and reproducibility. The respective AX control standards showed RR within the range of 95-105% without exception. To validate and show the ruggedness of the modified method, WEAX concentration in seven commercial German beers (e.g., lager, pilsner, wheat beer, non-alcoholic beer) was quantified. Interfering hexose sugars that lead to measurement errors when analyzing samples with high amounts of fermentable sugars (e.g., non-alcoholic beer produced by limited fermentation) were eliminated by Saccharomyces diastaticus fermentation. Further investigations were carried out by means of LC-MS in order to obtain additional information about the reddish product in the hydrolyzed samples. In this context, C16H12O6 could be identified as one of numerous condensation products, contributing to the coloring. The collected data showed the impact of diverse factors on the measured AX concentration and helped optimize the experimental procedure for a high sample throughput with precise and highly reproducible results. The proposed quantification method should be primarily used in completely fermented finished beer to emphasize the time aspect. Wort samples and non-alcoholic beer produced by limited fermentation can be also analyzed, but only after fermentation with S. diastaticus.

Effect of molar mass and size of non-alcoholic beer fractions and their relevance toward palate fullness intensity

Palate fullness intensity and mouthfeel descriptors are essential sensory characteristics of non-alcoholic beers (NABs). The descriptor's perception might be influenced by the molar distribution of the non-volatile matrix in cereal-based beverages like NABs. However, only limited information is available on the molar mass of different substances in NABs. This study investigated the role of weight average molar mass (M_w) and size of NABs fractions and their relation to sensory perception. Industrialized bottom-fermented NABs (n = 28) from the German market and NABs produced by different methods were used in this study. A trained sensory panel evaluated palate fullness intensity, mouthfeel, and basic taste descriptors (as additional quality parameters). Asymmetric flow field-flow fractionation was used to fractionate NABs, while M_w was determined by multi-angle light scattering and differential refractive index detectors. The NABs were fractionated into three groups containing different substances: proteins, proteins-polyphenol complexes (P-PC) and low molar mass (non-)starch polysaccharides (LN-SP), and high molar mass (non-)starch polysaccharides (HN-SP). The M_w range of proteins was 18.3-41 kDa, P-PC and LN-SP 43-122.6 kDa, and HN-SP 0.40-2.18·10³ kDa. Harmony, defined as the sweet and sour ratio, influenced the palate fullness intensity perception. In the harmonic samples (sour/sweet sensory balanced), the size of HN-SP (> 25 nm) showed a positive correlation to palate fullness intensity. The results suggest the importance of dextrins, arabinoxylan, and β-glucan in modulating the sensory characteristics of harmonic bottom-fermented NABs.

The occurrence and structural heterogeneity of arabinoxylan in commercial pilsner beers and their non-alcoholic counterparts

The impact of arabinoxylan (AX) on the brewing process and beer characteristics depends on its content and structure and is often overlooked in research and industry. This paper reports on the occurrence and structural heterogeneity of AX in a set of commercial pilsner beers and their non-alcoholic counterparts. Fractionation by graded ethanol precipitation allowed us to isolate AX-rich fractions from beer with a number-average degree of polymerisation of 4 to 308 and an average degree of substitution in the range of 0.43 to 0.88. Pilsner beers had a higher content of high-molecular-weight AX than their non-alcoholic counterparts. The structural heterogeneity among the various commercial beers differed. By comparing the chemical composition of the beers, differences in beer production methods and ingredient selection were deduced and used to tentatively explain the differences in AX content and structural heterogeneity.

Recent Developments in Molecular Characterization, Bioactivity, and Application of Arabinoxylans from Different Sources

Arabinoxylan (AX) is a polysaccharide composed of arabinose, xylose, and a small number of other carbohydrates. AX comes from a wide range of sources, and its physicochemical properties and physiological functions are closely related to its molecular characterization, such as branched chains, relative molecular masses, and substituents. In addition, AX also has antioxidant, hypoglycemic, antitumor, and proliferative abilities for intestinal probiotic flora, among other biological activities. AXs of various origins have different molecular characterizations in terms of molecular weight, degree of branching, and structure, with varying structures leading to diverse effects of the biological activity of AX. Therefore, this report describes the physical properties, biological activities, and applications of AX in diverse plants, aiming to provide a theoretical basis for future research on AX as well as provide more options for crop breeding.

Non-starch polysaccharides in beer and brewing: A review of their occurrence and significance

It has become apparent that beer (both alcoholic and nonalcoholic) contains appreciable amounts of non-starch polysaccharides, a broad subgroup of dietary fiber. It is worth noting that the occurrence of non-starch polysaccharides in alcoholic beer does not imply this should be consumed as a source of nutrition. But the popularity of nonalcoholic beer is growing, and the lessons learnt from non-starch polysaccharides in brewing can be largely translated to nonalcoholic beer. For context, we briefly review the origins of dietary fiber, its importance within the human diet and the significance of water-soluble dietary fiber in beverages. We review the relationship between non-starch polysaccharides and brewing, giving focus to the techniques used to quantify non-starch polysaccharides in beer, how they affect the physicochemical properties of beer and their influence on the brewing process. The content of non-starch polysaccharides in both regular and low/nonalcoholic beer ranges between 0.5 - 4.0 g/L and are predominantly composed of arabinoxylans and β-glucans. The process of malting, wort production and filtration significantly affect the soluble non-starch polysaccharide content in the final beer. Beer viscosity and turbidity are strongly associated with the content of non-starch polysaccharides.

Potential of non-Saccharomyces yeast to produce non-alcoholic beer

Recently, non-Saccharomyces yeast have become very popular in wine and beer fermentation. Their interesting abilities introduce novel aromatic profiles to the fermented product. In this study, screening of eight non-Saccharomyces yeast (Starmerella bombicola, Lindnera saturnus, Lindnera jadinii, ZygoSaccharomyces rouxii, Torulaspora delbrueckii, Pichia kluyveri, Candida pulcherrima, and Saccharomycodes ludwigii) revealed their potential in non-alcoholic beer production. Conditions for non-alcoholic beer production were optimised for all strains tested (except T. delbrueckii) with the best results obtained at temperature 10 to 15 °C for maximum of 10 days. Starmerella bombicola, an important industrial producer of biosurfactants, was used for beer production for the first time and was able to produce non-alcoholic beer even at 20 °C after 10 days of fermentation. Aromatic profile of the beer fermented with S. bombicola was neutral with no negative impact on organoleptic properties of the beer. The most interesting organoleptic properties were evaluated in beers fermented with L. jadinii and L. saturnus, which produced banana-flavoured beers with low alcohol content. This work confirmed the suitability of mentioned yeast to produce non-alcoholic beers and could serve as a steppingstone for further investigation.

Prebiotics as a Tool for the Prevention and Treatment of Obesity and Diabetes: Classification and Ability to Modulate the Gut Microbiota

Diabetes and obesity are metabolic diseases that have become alarming conditions in recent decades. Their rate of increase is becoming a growing concern worldwide. Recent studies have established that the composition and dysfunction of the gut microbiota are associated with the development of diabetes. For this reason, strategies such as the use of prebiotics to improve intestinal microbial structure and function have become popular. Consumption of prebiotics for modulating the gut microbiota results in the production of microbial metabolites such as short-chain fatty acids that play essential roles in reducing blood glucose levels, mitigating insulin resistance, reducing inflammation, and promoting the secretion of glucagon-like peptide 1 in the host, and this accounts for the observed remission of metabolic diseases. Prebiotics can be either naturally extracted from non-digestible carbohydrate materials or synthetically produced. In this review, we discussed current findings on how the gut microbiota and microbial metabolites may influence host metabolism to promote health. We provided evidence from various studies that show the ability of prebiotic consumption to alter gut microbial profile, improve gut microbial metabolism and functions, and improve host physiology to alleviate diabetes and obesity. We conclude among other things that the application of systems biology coupled with bioinformatics could be essential in ascertaining the exact mechanisms behind the prebiotic–gut microbe–host interactions required for diabetes and obesity improvement.

Arabinoxylans as Functional Food Ingredients: A Review

The health benefits of fibre consumption are sound, but a more compressive understanding of the individual effects of different fibres is still needed. Arabinoxylan is a complex fibre that provides a wide range of health benefits strongly regulated by its chemical structure. Arabinoxylans can be found in various grains, such as wheat, barley, or corn. This review addresses the influence of the source of origin and extraction process on arabinoxylan structure. The health benefits related to short-chain fatty acid production, microbiota regulation, antioxidant capacity, and blood glucose response control are discussed and correlated to the arabinoxylan’s structure. However, most studies do not investigate the effect of AX as a pure ingredient on food systems, but as fibres containing AXs (such as bran). Therefore, AX’s benefit for human health deserves further investigation. The relationship between arabinoxylan structure and its physicochemical influence on cereal products (pasta, cookies, cakes, bread, and beer) is also discussed. A strong correlation between arabinoxylan’s structural properties (degree of branching, solubility, and molecular mass) and its functionalities in food systems can be observed. There is a need for further studies that address the health implications behind the consumption of arabinoxylan-rich products. Indeed, the food matrix may influence the effects of arabinoxylans in the gastrointestinal tract and determine which specific arabinoxylans can be included in cereal and non-cereal-based food products without being detrimental for product quality.

Isolation, Structural, Functional, and Bioactive Properties of Cereal Arabinoxylan─A Critical Review

Arabinoxylans (AXs) are widely distributed in various cereal grains, such as wheat, corn, rye, barley, rice, and oat. The AX molecule contains a linear (1,4)-β-D-xylp backbone substituted by α-L-araf units and occasionally t-xylp and t-glcpA through α-(1,2) and/or α-(1,3) glycosidic linkages. Arabinoxylan shows diversified functional and bioactive properties, influenced by their molecular mass, branching degree, ferulic acid (FA) content, and the substitution position and chain length of the side chains. This Review summarizes the extraction methods for various cereal sources, compares their structural features and functional/bioactive properties, and highlights the established structure-function/bioactivity relationships, intending to explore the potential functions of AXs and their industrial applications.

Autochthonous Biological Resources for the Production of Regional Craft Beers: Exploring Possible Contributions of Cereals, Hops, Microbes, and Other Ingredients

Selected biological resources used as raw materials in beer production are important drivers of innovation and segmentation in the dynamic market of craft beers. Among these resources, local/regional ingredients have several benefits, such as strengthening the connection with territories, enhancing the added value of the final products, and reducing supply costs and environmental impacts. It is assumed that specific ingredients provide differences in flavours, aromas, and, more generally, sensory attributes of the final products. In particular, of interest are ingredients with features attributable and/or linked to a specific geographical origin. This review encompasses the potential contribution and exploitation of biodiversity in the main classes of beer inputs, such as cereals, hops, microbes, and adjuncts, with a specific emphasis on autochthonous biological resources, detailing the innovative paths already explored and documented in the scientific literature. This dissertation proposes an overview of the impact on beer quality for each raw material category, highlighting the benefits and limitations that influence its concrete applications and scale-up, from the field to the stain. The topics explored promote, in the sector of craft beers, trends already capitalised in the production of other alcoholic beverages, such as the preservation and revalorisation of minor and autochthonous varieties, the exploitation of yeast and bacteria strains isolated from specific sites/plant varieties, and the valorisation of the effects of peculiar terroirs on the quality of agricultural products. Finally, the examined tendencies contribute toward reducing the environmental impacts of craft beer manufacturing, and are in line with sustainable development of food systems, increasing the economic driver of biodiversity preservation.

Recent innovations in the production of selected specialty (non-traditional) beers

Customer demand for product diversity is the key driving force for innovations in the brewing industry. Specialty beers are regarded as a distinct group of beers different from two major types, lagers and ales, without established definitions or boundaries. Specialty beers, including low- to no-alcohol beer, low carbohydrate beer, gluten-free beer, sour beer, probiotic beer, and enriched beer, are exclusively brewed and developed keeping in mind their functionality, the health and wellbeing of the consumer, and emerging market trends. Compared with conventional beer-brewing, the production of specialty beers is technologically challenging and usually requires additional process steps, unique microorganisms, and special equipment, which in turn may incur additional costs. In addition, the maintenance of quality and stability of the products as well as consumer acceptability of the products are major challenges to successful commercialization. A harmonious integration of traditional brewing practices and modern technological approaches may hold potential for future developments. In the present review, latest developments in the fermentative production of selected specialty beers are discussed.