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Partial substitution of barley malt by wheat bran in the grist results in lager beer with better taste profile and higher content in arabinoxylan- oligosaccharides (AXOS)
Abstract
The use of wheat bran as a new adjunct in brewing at 25 % of total grist in combination with the use of a xylanase in the mashing step was tested by brewing control and bran-brewed lager beers. Sensory analysis revealed marked improvements in taste profile due to bran-brewing, with statistically significant increase in body, smoothness and warming notes, and a decrease in acetaldehyde, after-bitterness, drying and grainy attributes. A detailed physico-chemical analysis of the beers was performed. Key parameters on which a significant impact was demonstrated include increased content of arabinoxylanoligosaccharides (AXOS), ferulic acid, and soluble protein, and lowered content of aldehydes, the latter indicative of reduced oxidation during brewing. Traditional but long forgotten use of wheat bran for brewing of small beers holds potential to make innovative beers with an interesting taste profile.
Functional beers are increasing in popularity amid the craft beer movement and rising trends in health and wellness. Within this category, probiotic and prebiotic beers are a novelty and, due to their health benefits, could make significant contributions within the brewing industry. Studies exploring the use of different types of probiotics (Lactobacillus spp., Saccharomyces cerevisiae var. boulardii, and Bacillus spp.) to brew beers have recently emerged. In contrast, prebiotic beers remain relatively unexplored, which is unfortunate as there is great potential in enriching beers with the candidate prebiotics, arabinoxylan-oligosaccharides, and β-glucans, via in situ production. Nevertheless, there are difficulties in developing probiotic and prebiotic beers, and very often, modifications to existing brewing practices need to be made. Furthermore, despite potential therapeutic benefits compared to regular beers, health-promoting messages must abide by local legislations in order to safeguard consumer health against the deleterious effects of excessive alcohol consumption.
The purpose of this research on wheat beer was to identify the most important acceptance-causing sensory attributes for wheat beer. For this reason, specific attributes were developed and 18 wheat beers were analysed in a sensorily descriptive format. The determination of acceptance was achieved by testing products in the target group (n=148). Twelve wheat beers were evaluated, which were chosen for their sensory properties. By linking sensory description and acceptance values, significant attributes for wheat beer that are responsible for acceptance were detected. Subsequently, split analyses based on gender, age and consumption intensity were performed. Wheat beers can be described using twenty sensory terms, which demonstrates that there is great product diversity. Wheat beers indicate different sensory qualities: fruity, non-fruity, bitter and mouthcoating, tingly or sweet and creamy. Wheat beers with a creamy mouthfeel were preferred by consumers, while bitter and non-fruity-smelling wheat beers were not well-liked. In investigating the acceptance of various subgroups, it was discovered that women had a greater preference for wheat beers with a creamy mouthfeel than did men. In comparison to younger beer consumers, consumers over the age of 40 showed no differentiation in their acceptance of wheat beers. On the other hand, beer drinkers under 40 years preferred "creamy" wheat beers with a banana-like odour. Wheat beers with an above-average rating for the attribute "banana" were significantly more often preferred amongst consumers who drink wheat beer two to three times a month or more than by consumers who drink wheat beer only once a month or less.
Age-induced decomposition of iso-α-acids, the main bittering principles of beer, determines the consistency of the beer bitter taste. In this study, the profiles of iso-α-acids in selected high-quality top-fermented and lager beers were monitored by quantitative high-performance liquid chromatography at various time intervals during ageing. The degradation of the iso-α-acids as a function of time is represented by the ratio, in percentage, of the sum of the concentrations of trans-isocohumulone and trans-isohumulone to the sum of the concentrations of cis-isocohumulone and cis-isohumulone. This parameter is relevant with respect to the evaluation of bitterness deterioration in aged beers. Trans-iso-α-acids having a shelf half-life of less than one year proved to be significantly less stable than cis-iso-α-acids, but it appears feasible to counteract degradation if a suitable beer matrix is available. The fate of the trans-iso-α-acids in particular adversely affects beer bitterness consistency. In addition to using hop products containing low amounts of trans-iso-α-acids, brewers may profit of the remarkable stability of tetrahydroiso-α-acids, even on prolonged storage, for the production of consistently bitter beers.
Polypeptides from beer and from aqueous extracts of barley have been separated by hydrophobic interaction chromatography. The most stable foams are given by polypeptides of greatest hydrophobic character whereas hydrophilic polypeptides give much less stable foams. This effect is most pronounced in polypeptides of molecular size between 5000 and 30,000 and less so in the case of high molecular weight polypeptides (> 50,000).
Attempts to find a solution to the problem of beer staling have been unremitting: hundreds of articles have been published during the last few years alone. This paper introduces recent developments in brewing science and discusses basic research into the formation of stale flavors, together with measures proposed and adopted to counter them. Included are advances made both in brewing technology and beer distribution systems, which help minimize staling, with an example of product temperature management used by a Japanese company.
The antioxidant activity of feruloyl arabinose, a model substance of cereal cell-wall fragments, in the LDL autoxidation system by CuSO4 and its absorption were studied. Ferulic acid added as free acid showed little suppressive effect on LDL oxidation. However, ferulic acid sugar esters showed a positive effect. This fact indicated that affinity of LDL particle and free or bound ferulic acid is important for the suppressive effect. The HPLC analysis showed that in rats administered feruloyl arabinose, two peaks were detected with retention times lower than those of feruloyl arabinose and ferulic acid, which appeared upon β-glucuronidase/sulfatase treatment. The study showed that the absorbed form of FAA could be a more polar compound, possibly a conjugated form. Keywords: Antioxidant; low-density lipoprotein; cereal cell wall; ferulic acid sugar ester
J. Inst. Brew. 113(2), 185–195, 2007 Ferulic acid (4-hydroxy-3-methoxycinnamic acid), predomi-nantly in ester form in arabinoxylan chains, is the main phenolic acid present in barley and malt. Only about 1% of the total fe-rulic acid in barley is present in the free form. A number of pre-vious works concerned the contents of free and esterified ferulic acid in a broad range of popular beers, but there is little informa-tion about the possible composition of feruloylated oligosaccha-rides in beers. The aim of this preliminary work was to purify the feruloylated oligosaccharides from lager beers (by the means of preparative chromatography) followed by composition eluci-dation using TLC, HPLC with RI or UV detection and 1 H-NMR. Indeed, the qualitative analyses of isolated fractions from beer revealed that the fractions contained ferulic acid in the ester form (as proven after mild alkaline hydrolysis). It was also shown that molecular masses of oligosaccharides present in the purified beer fractions were similar to the masses of arabinose and xylooligosaccharides in the range of xylose to xylohexaose. Although a number of purified beer samples contained oligosac-charides of higher molecular masses, these were not further characterized. Taking under consideration the presented results, it can be concluded that beer can be a good source of feru-loylated oligosaccharides, significant in the context of human health benefits.