Sequential Extraction and Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy Monitoring in the Biorefining of Brewer's Spent Grain.

The brewing industry plays a significant role in producing a substantial annual volume of by-products, which contributes to the global accumulation of food waste. The primary by-product generated is brewer's spent grain (BSG), a lignocellulosic biomass rich in proteins, fiber, and moisture content. Leveraging biorefining and valorization techniques for BSG represents a promising strategy to enhance sustainability, resilience, and circularity within the brewing chain. To date, most studies have focused on extracting proteins from BSG. Yet, it is crucial to note that the fiber part of BSG also holds considerable potential for biorefining processes. This study introduces a novel sequential extraction method designed to integrally recover the major components of BSG. Notably, it introduces a reactive extraction approach that enables the simultaneous extraction and tuneable functionalization of the hemicellulose component. Additionally, the study assesses the utility of the attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy as a user-friendly tool to monitor and evaluate the effectiveness of the fractionation process. This spectroscopic technique can provide valuable insights into the changes and composition of BSG throughout the extraction process.

Species and temperature-dependent fermentative aptitudes of Mrakia genus for innovative brewing.

The use of non-conventional brewing yeasts as alternative starters is a very promising approach which received increasing attention from worldwide scientists and brewers. Despite the feasible application of non-conventional yeasts in brewing processes, their regulations and safety assessment by the European Food Safety Authority still represent a bottlenecked hampering their commercial release, at least into EU market. Thus, research on yeast physiology, accurate taxonomic species identification and safety concerns associated with the use of non-conventional yeasts in food chains is needed to develop novel healthier and safer beers. Currently, most of the documented brewing applications catalysed by non-conventional yeasts are associated to ascomycetous yeasts, while little is known about analogous uses of basidiomycetous taxa. Therefore, in order to extend the phenotypic diversity of basidiomycetous brewing yeasts the aim of this investigation is to check the fermentation aptitudes of thirteen Mrakia species in relation to their taxonomic position within the genus Mrakia. The volatile profile, ethanol content and sugar consumption were compared with that produced by a commercial starter for low alcohol beers, namely Saccharomycodes ludwigii WSL 17. The phylogeny of Mrakia genus showed three clusters that clearly exhibited different fermentation aptitudes. Members of M. gelida cluster showed a superior aptitude to produce ethanol, higher alcohols, esters and sugars conversion compared to the members of M. cryoconiti and M. aquatica clusters. Among M. gelida cluster, the strain M. blollopis DBVPG 4974 exhibited a medium flocculation profile, a high tolerance to ethanol and to iso-α-acids, and a considerable production of lactic and acetic acids, and glycerol. In addition, an inverse relationship between fermentative performances and incubation temperature is also displayed by this strain. Possible speculations on the association between the cold adaptation exhibited by M. blollopis DBVPG 4974 and the release of ethanol in the intracellular matrix and in the bordering environment are presented.

Influence of malt composition on the quality of a top fermented beer.

The beer is a widely consumed drink, appreciated for its sensory characteristics, and it also contains beneficial compounds for health derived from its raw materials. In this work, the influence of coloured malt on the main quality parameters of a top-fermenting beer was evaluated. The beers were produced increasing the percentage of coloured malt (0, 5, 15% Caraamber®) respect to the pale ale base malt. The beers had an alcohol content ranging from 6.2 to 6.8 vol%; the results highlighted a deeper colour, increased bitterness and turbidity in beer with the highest amount of Caraamber malt. This latter showed the highest polyphenols (453.8 mg GAE/L) and antioxidant activity (840.1 µmol TE/L) and, on the other hand, the lowest foam stability. The volatiles profile showed a higher amount of aldehydes and ketones in beer with the highest percentage of caramel malt but the lowest in higher alcohols and esters. No differences were found in the fruity-esters, alcoholic and caramel sensory notes; while the beer made with 15% of coloured malt was perceived sweeter and with less fruity citrus notes than other beer samples.

Influence of the dealcoholisation by osmotic distillation on the sensory properties of different beer types.

A comparative study was performed to better understand the feasibility of osmotic distillation as a process to produce a low-alcohol beer. Four diverse commercial beers styles were considered. The regular and corresponding dealcoholised beers were compared. The quality attributes and the volatile compounds loss after the dealcoholisation were checked. The work focused on the sensory properties of the obtained samples. A trained panel evaluated how the chosen sensory descriptors were influenced by the treatment. The results of quality attributes and volatile compounds were in line with works previously published by the authors. Interestingly, the results highlighted that beer characterized by malty character is more suitable than pale lager to be dealcoholised by the osmotic distillation process. The low alcohol milk stout and stout flavour profile, especially in terms of taste, was like the corresponding regular beer. Osmotic distillation was demonstrated to be a feasible process to produce low-alcohol beer.

Sourdough cultures as reservoirs of maltose-negative yeasts for low-alcohol beer brewing.

De novo sourdough cultures were here assessed for their potential as sources of yeast strains for low-alcohol beer brewing. NGS analysis revealed an abundance of ascomycete yeasts, with some influence of grain type on fungal community composition. Ten different ascomycete yeast species were isolated from different sourdough types (including wheat, rye, and barley) and seven of these were screened for a number of brewing-relevant phenotypes. All seven were maltose-negative and produced less than 1% (v/v) alcohol from a 12 °Plato wort in initial fermentation trials. Strains were further screened for their bioflavouring potential (production of volatile aromas and phenolic notes, reduction of wort aldehydes), stress tolerance (temperature extremes, osmotic stress and ethanol tolerance) and flocculence. Based on these criteria, two species (Kazachstania servazzii and Pichia fermentans) were selected for 10 L-scale fermentation trials and sensory analysis of beers. The latter species was considered particularly suitable for production of low-alcohol wheat beers due to its production of the spice/clove aroma 4-vinylguaiacol, while the former showed potential for lager-style beers due to its clean flavour profile and tolerance to low temperature conditions.

Effect of Addition of Different Phenolic-Rich Extracts on Beer Flavour Stability.

Flavour stability is a key factor in the beer production process. The stabilizing effect of six commercial phenolic-rich extracts was studied. The extracts were added to beer before bottling. Quality parameters (colour, turbidity, foam and dissolved oxygen content), antioxidant activity by 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), total polyphenols content, and sensorial analysis by a trained panel were performed over the course of storage. The beers were analyzed every 3 months for a total period of 6 months. Results indicated that all studied phenolic-rich extracts positively affected the beer flavour stability. In particular, the condensed tannins showed a significant protective effect. The condensed green tea tannins resulted as the most promising source of natural antioxidant able to prolong beer shelf-life and bring interesting organoleptic characteristics to beer. Also, grape seed tannins appeared suitable to boost flavour stability and improve organoleptic properties of beer.

Novel Fast Identification and Determination of Free Polyphenols in Untreated Craft Beers by HPLC-PDA-ESI-MS/MS in SIR Mode.

Many analytical methods for polyphenol determination in food and beverages can be found in the literature, but most of them need time-consuming sample pretreatment. Conversely, methods are missing for a rapid screening of non-pre-treated samples, with useful application in the agri-food industry, from process control to fraud. Selected ion recording mass mode after liquid chromatographic separation was used for the detection and quantification of free polyphenols in three craft beers, after just degassing, filtering, and diluting the beer samples with the mobile phase prior to the analysis. Fourteen polyphenols including hydroxybenzoic acids, hydroxycinnamic acids, and flavonols were chosen as standards. Nine of them were identified and quantified in at least one of the analyzed craft beers, despite the low content and the complexity of the samples. Depending on the analyte, 80-7 µg/L as the limit of detection (LOD) and 240-30 µg/L as the limit of quantification (LOQ) were found. Satisfactory results for interday and intraday precisions, accuracy, recovery, and matrix effect were found. The one-factor analysis of variance (ANOVA) on the three different craft beers was statistically significant, with P < 0.05. The electrospray ionization mass fingerprinting of the same non-pre-treated craft beers was also investigated for wider characterization. Diagnostic ions were found and identified as deriving from oligosaccharides, organic acids, and amino acids.

Mrakia gelida in brewing process: An innovative production of low alcohol beer using a psychrophilic yeast strain.

Due to the increasing consumer demand, the production of low alcoholic and non alcoholic beer is the new goal of the present brewing producers. Although the beer with reduced alcohol content is currently obtained by physical methods, the use of non-Saccharomyces yeast, with low fermentations capacities, may represent an interesting biological approach. In this study the ethanol content and the volatile profile of a beer obtained using the basidiomycetous psychrophilic yeast strain Mrakia gelida DBVPG 5952 was compared with that produced by a commercial starter for low alcohol beers, Saccharomycodes ludwigii WSL17. The two beers were characterized by a low alcohol content (1.40% and 1.32% v/v) and by a low diacetyl production (5.04 and 5.20 µg/L). However, the organoleptic characteristics of the beer obtained using M. gelida are more appreciated by the panelists, in comparison to the analogous produced with the commercial strain of S. ludwigii.

Effects of Operating Conditions during Low-Alcohol Beer Production by Osmotic Distillation.

Osmotic distillation (OD) is a membrane technology most commonly used for liquid concentration, but recently there has been an increased interest in ethanol removal from alcoholic beverages. The aim of this paper is to investigate the effect of the variation of some operating conditions (temperature, flow rate, type and amount of stripping solution), specifically in regard to the effect on quality and sensory properties of the dealcoholized beers. The results indicated that temperature and flow rate variation showed no significant effect, whereas stripping solution variation had substantial effects mainly in terms of the ethanol removed. A cost appraisal showed that the operating costs were high mainly because of the cost of the stripping water. However, it is important to consider the final stripping solution, which is slightly alcoholic and enriched in flavor. For this reason, it could be reused in the manufacture of beverages, for instance as high gravity beer dilution water.

Reactive oxygen species are involved in ferroportin degradation induced by ceruloplasmin mutant Arg701Trp.

The ceruloplasmin mutant R701W, that causes a dramatic phenotype in the young heterozygous patient carrying this mutation, has been shown to have profound effects also in cell culture models. Here we show that Golgi rearrangement and degradation of the iron exporter ferroportin, that follow transfection of cells with this mutant, are accompanied by the massive production of reactive oxygen species (ROS) in the cell. Scavenging ROS production with different antioxidants, including reduced glutathione and zinc, restores Golgi morphology and rescues ferroportin on the cell membrane.

Role of external loops of human ceruloplasmin in copper loading by ATP7B and Ccc2p.

Ceruloplasmin is a multicopper oxidase required for correct iron homeostasis.Previously, we have identified a ceruloplasmin mutant associated with the iron overload disease aceruloplasminemia, which was unable to acquire copper from the mammalian pump ATP7B but could be produced in an enzymatically active form in yeast. Here, we report the expression of recombinant ceruloplasmin in the yeast Pichia pastoris and the study of the role of five surface-exposed loops in copper incorporation by comparing the efficiencies of mammalian ATP7B and yeast Ccc2p. The possibility to "mix and match" mammalian and yeast multicopper oxidases and copper ATPases can provide clues on the molecular features underlying the process of copper loading in multicopper oxidases.

Dominant mutants of ceruloplasmin impair the copper loading machinery in aceruloplasminemia.

The multicopper oxidase ceruloplasmin plays a key role in iron homeostasis, and its ferroxidase activity is required to stabilize cell surface ferroportin, the only known mammalian iron exporter. Missense mutations causing the rare autosomal neurodegenerative disease aceruloplasminemia were investigated by testing their ability to prevent ferroportin degradation in rat glioma C6 cells silenced for endogenous ceruloplasmin. Most of the mutants did not complement (i.e. did not stabilize ferroportin) because of the irreversible loss of copper binding ability. Mutant R701W, which was found in a heterozygous very young patient with severe neurological problems, was unable to complement per se but did so in the presence of copper-glutathione or when the yeast copper ATPase Ccc2p was co-expressed, indicating that the protein was structurally able to bind copper but that metal loading involving the mammalian copper ATPase ATP7B was impaired. Notably, R701W exerted a dominant negative effect on wild type, and it induced the subcellular relocalization of ATP7B. Our results constitute the first evidence of "functional silencing" of ATP7B as a novel molecular defect in aceruloplasminemia. The possibility to reverse the deleterious effects of some aceruloplasminemia mutations may disclose new possible therapeutic strategies.