Critical review of the methods of β-glucan analysis and its significance in the beer filtration process

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.

Characterization of molar mass and conformation of relevant (non-)starch polysaccharides in cereal-based beverages

Arabinoxylans, β-glucans, and dextrins influence the brewing industry's filtration process and product quality. Despite their relevance, only a maximum concentration of β-glucans is recommended. Nevertheless, filtration problems are still present, indicating that although the chemical concentration is essential, other parameters should be investigated. Molar mass and conformation are important polymer physical characteristics often neglected in this industry. Therefore, this research proposes an approach to physically characterize enzymatically isolated beer polysaccharides by asymmetrical flow field-flow fractionation coupled to multi-angle light scattering and differential refractive index detector. Based on the obtained molar masses, root-mean-square radius (rrms from MALS), and hydrodynamic radius (rhyd), conformational properties such as apparent density (ρapp) and rrms/rhyd can be calculated based on their molar mass and size. Consequently, the ρapp and rrms/rhyd behavior hints at the different structures within each polysaccharide. The rrms/rhyd 1.2 and high ρapp values on low molar mass dextrins (1-2·105 g/mol) indicate branches, while aggregated structures at high molar masses on arabinoxylans and β-glucans (2·105 -6·106 g/mol) are due to an increase of ρapp and a rrms/rhyd (0.6-1). This methodology provides a new perspective to analyze starch and non-starch polysaccharides in cereal-based beverages since different physical characteristics could influence beer's filtration and sensory characteristics.

Influence of Hydrothermal Treatment of Brewer's Spent Grain on the Concentration and Molecular Weight Distribution of 1,3-1,4-β-D-Glucan and Arabinoxylan

Brewer's spent grain (BSG) is the most abundant residual in the brewing process. Non-starch polysaccharides such as 1,3-1,4-β-D-glucan (β-glucan) and arabinoxylan (AX) with proven beneficial effects on human health remain in this by-product in high amounts. Incorporating the valuable dietary fiber into the food industry could contribute to a healthy diet. However, a major challenge is extracting these dietary fibers (i.e., β-glucan and AX) from the solid residue. In this study, hydrothermal treatment (HT) was applied to dissolve the remaining water-insoluble carbohydrates from BSG with the aim to extract high amounts of β-glucan and AX. Particular focus was placed on the molecular weight (MW) range above 50 kDa and 20 kDa, respectively, as these are considered to have health-promoting effects. Different treatment temperatures, reaction times, and internal reactor pressures were tested to determine the best process settings to achieve high yields of β-glucan and AX and to examine the influence on their molecular weight distribution (MWD). Overall, 85.1% β-glucan and 77.3% AX were extracted corresponding to 6.3 g per kg BSG at 160 °C and 178.3 g kg-1 at 170 °C, respectively. However, less than 20% of both fiber substances were in the desirable MW range above 50 kDa and 20 kDa, respectively. When lower temperatures of 140 and 150 °C were applied, yields of only 3.0 g kg-1 β-glucan and 128.8 g kg-1 AX were obtained, whereby the proportion of desirable fiber fractions increased up to 45%. Further investigations focused on the heat-induced degradation of monosaccharides and the formation of undesirable by-products (i.e., HMF and furfural) that might pose a health risk.

Extraction and characterization of waxy and normal barley β-glucans and their effects on waxy and normal barley starch pasting and degradation properties and mash filtration rate

Interactions between β-glucan and starch influence the health benefits of barley-based foods and barley brewing performance. Here, we characterized β-glucans from waxy and normal barley varieties and compared the effects of different β-glucans on the pasting and degradation of waxy and normal barley starches as well as the filterability of mashes from unmalted waxy and normal barley. Waxy barley Zangqing18 β-glucan displayed more compact micrographic features, higher molecular weight, larger particle size, higher thermal decomposition temperature and lower rheological viscosity than normal barley Zangqing2000 β-glucan. β-Glucan not only significantly decreased the pasting viscosities of waxy and normal starches but also lowered the pasting temperatures and peak times of normal starch, likely by inhibiting granule swelling and disrupting the integrity of the continuous phase. β-Glucan also decreased in vitro digestion extent of starch and increased the resistant starch. The unmalted waxy barley had a mash filtration rate much faster than normal barley because starch and β-glucan in waxy barley were rapidly and completely digested and formed more open filter passages. The effects of β-glucan on starch properties varied with the types and contents of β-glucans, whilst the types of starches showed more significant effects. CHEMICAL COMPOUNDS STUDIED: β-Glucan (Pubchem CID: 439262); Amylopectin (Pubchem CID: 439207); Starch (Pubchem CID: 156595876).

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.

Chemometric modeling of palate fullness in lager beers

Palate fullness and mouthfeel of beer are key attributes of sensory beer quality. Non-volatile substances and molar mass fractions influence sensory perceptions of palate fullness and mouthfeel. However, systematic correlations between sensory attributes and native beer compounds have not been evaluated within the concentration range found in lager beer. This article reports a chemometric analysis of 41 lager beers by evaluating analytical data of beer compositions, palate fullness, and mouthfeel descriptors. AF4-MALS-dRI indicated high variability in the macromolecular compositions of classical lager beers. Screened beers were clustered into groups differing significantly in palate fullness intensity and macromolecular distribution. Significant correlations were found between palate fullness and macromolecular fractions and beer composition parameters: original gravity, viscosity, indices of macromolecular distribution, total nitrogen (p < 0.001), and β-glucan (p < 0.01). Thus, a model was built using partial least square regression (PLS) analysis to predict the palate fullness intensity in beers (R²_C = 0.7993). This model can be used as a guideline by brewers to control palate fullness and mouthfeel.

Influence of malt modification and the corresponding macromolecular profile on palate fullness in cereal-based beverages

The sensory attribute palate fullness of cereal-based beverages was shown to be affected by polymeric compounds and their macromolecular profile. During malting, the enzymatic degradation of polymers is technologically controlled by the malting parameters, namely the degree of steeping, germination time, and germination temperature. The macromolecular profile of a fermented cereal-based beverage consists of non-fermentable substance classes. Therefore, the macromolecular composition of a final beverage is originally dominated by the raw material, if conventional production methods are used. We investigated the influence of different cytolytic and proteolytic malt modifications on the macromolecular profile of lactic acid-fermented cereal-based beverages (a strain was selected that did not produce exopolysaccharides) and their resultant effect on the sensory perception of the attributes of palate fullness and mouthfeel. Asymmetrical-flow field-flow fractionation coupled with multi-angle light-scattering detection and refractive index detection is an analytical tool for macromolecular characterization to indicate differences in the macromolecular profile, molar mass, and molar mass distribution. The beverages produced using different modified malts demonstrated a considerable variation in their final composition, particularly in the composition of their macromolecular compounds. A higher level of malt modification led to a decrease in the high-molar-mass fraction and a consequent shift toward fractions with a lower molar mass. Malts produced from barley with increased crude protein contents resulted in a greater range within the macromolecular profile. The variation of germination time significantly influenced the number average molar mass, the total refractive index detection (dRI) peak area, and the high-molar-mass fraction, which contained cell wall polysaccharides (60–1200 kDa). The perception of the intensity of palate fullness was significantly correlated with specific macromolecular fractions, which were influenced by the malting parameter degree of steeping and the resultant modification. The perception of the mouthfeel descriptor watery varied significantly for different crude protein contents. Our results are beneficial for a targeted design of beverage composition based on the macromolecular profile by an improved selection of raw materials and malting technology.

Cereal B-Glucans: The Impact of Processing and How It Affects Physiological Responses

Cereal β-glucans are dietary fibres primarily found in oats and barley, and have several positive effects on health, including lowering the postprandial glucose response and the improvement of blood cholesterol levels. Cereal β-glucans have a specific combination of β-(1→4) and β-(1→3) linkages into linear long-chain polysaccharides of high molecular weight. Due to their particular structure, cereal β-glucans generate viscosity within the intestinal tract, which is thought to be the main mechanism of action responsible for their positive health effects. However, cereal grains are rarely consumed raw; at least one cooking step is generally required before they can be safely eaten. Cooking and processing methods more generally will modify the physicochemical characteristics of β-glucans, such as molecular weight, extractability and the resulting viscosity. Therefore, the health impact of β-glucans will depend not only on the dose administered, but also on the ways they are processed or converted into food products. This review aims at summarizing the different parameters that can affect β-glucans efficacy to improve glucose and lipid metabolism in humans.

Impact of flavouring substances on the aggregation behaviour of dissolved barley β-glucans in a model beer

Structural polymers such as cereal β-glucan may cause various processing problems in beverage industry depending on concentration, molar size distribution and agglomeration behaviour. In this context, influences of the beer volatiles dodecanoic acid, octyl butanoate, ethyl decanoate and decyl acetate on molar mass and radii of barley β-glucan were investigated in ethanolic (4% w/w) model solution. After addition of 100mg/l ethyl decanoate and decyl acetate to the β-glucan solution, a wider-ranging molar mass distribution could be observed by means of asymmetric field-flow-fractionation. Due to agglomeration, average molar mass of β-glucan standard (MW=6.8×10(6)g/mol) increased by 2×10(6)g/mol (P<0.05) in solution containing decyl acetate. Furthermore, a significant growth (P<0.05) from 86 to 102 nm in gyration radius was measured. The obtained results elucidate the importance of fatty acid derived flavouring substance composition in beer regarding the aggregation behaviour of β-glucan.