Cover crop performance under a changing climate in continuous corn system over Nebraska.

Fall-planted cover crop (CC) within a continuous corn (Zea mays L.) system offers potential agroecosystem benefits, including mitigating the impacts of increased temperature and variability in precipitation patterns. A long-term simulation using the Decision Support System for Agrotechnology Transfer model was made to assess the effects of cereal rye (Secale cereale L.) on no-till continuous corn yield and soil properties under historical (1991-2020) and projected climate (2041-2070) in eastern Nebraska. Local weather data during the historical period were used, while climate change projections were based on the Canadian Earth System Model 2 dynamically downscaled using the Canadian Centre for Climate Modelling and Analysis Regional Climate Model 4 under two representative concentration pathways (RCP), namely, RCP4.5 and RCP8.5. Simulations results indicated that CC impacts on corn yield were nonsignificant under historical and climate change conditions. Climate change created favorable conditions for CC growth, resulting in an increase in biomass. CC reduced N leaching under climate change scenarios compared to an average reduction of 60% (7 kg ha- 1 ) during the historical period. CC resulted in a 6% (27 mm) reduction in total water in soil profile (140 cm) and 22% (27 mm) reduction in plant available water compared to no cover crop during historical period. CC reduced cumulative seasonal surface runoff/soil evaporation and increased the rate of soil organic carbon buildup. This research provides valuable information on how changes in climate can impact the performance of cereal rye CC in continuous corn production and should be scaled to wider locations and CC species.

Malate production, sugar metabolism, and redox homeostasis in the leaf growth zone of Rye (Secale cereale) increase stress tolerance to aluminum stress: A biochemical and genome-wide transcriptional study.

Global soil acidification is increasing, enlarging aluminum (Al) availability in soils, leading to reductions in plant growth. This study investigates the effect of Al stress on the leaf growth zones of Rye (Secale cereale, cv Beira). Kinematic analysis showed that the effect of Al on leaf growth rates was mainly due to a reduced cell production rate in the meristem. Transcriptomic analysis identified 2272 significantly (log2fold > |0.5| FDR < 0.05) differentially expressed genes (DEGs) for Al stress. There was a downregulation in several DEGs associated with photosynthetic processes and an upregulation in genes for heat/light response, and H2O2 production in all leaf zones. DEGs associated with heavy metals and malate transport were increased, particularly, in the meristem. To determine the putative function of these processes in Al tolerance, we performed biochemical analyses comparing the tolerant Beira with an Al sensitive variant RioDeva. Beira showed improved sugar metabolism and redox homeostasis, specifically in the meristem compared to RioDeva. Similarly, a significant increase in malate and citrate production, which are known to aid in Al detoxification in plants, was found in Beira. This suggests that Al tolerance in Rye is linked to its ability for Al exclusion from the leaf meristem.

Characteristic of the gene candidate SecARS encoding alkylresorcinol synthase in Secale.

BACKGROUND: Alkylresorcinols (ARs) are compounds belonging to the class of phenolic lipids. A rich source of ARs are cereal grains such as rye, wheat, triticale or barley. ARs found in plants are characterized by a variety of biological properties such as antimicrobial, antifungal and cytotoxic activity. Moreover, they are proven to have a positive influence on human health. Here, we aimed to find and characterize the gene with ARs synthase activity in the species Secale cereale. METHODS AND RESULTS: Using BAC library screening, two BAC clones containing the gene candidate were isolated and sequenced. Bioinformatic analyses of the resulting contigs were used to examine the structure and other features of the gene, including promoter, intron, 3'UTR and 5'UTR. Mapping using the FISH procedure located the gene on the 4R chromosome. Comparative analysis showed that the gene is highly similar to sequences coding for type III polyketide synthase. The level of gene expression in various parts of the plant was investigated, and the biochemical function of the gene was confirmed by heterologous expression in yeast. CONCLUSIONS: The conducted analyses contributed to a better understanding of the processes related to ARs synthesis. Although the research concerned the rye model, the knowledge gained may help in understanding the genetic basis of ARs biosynthesis in other species of the Poaceae family as well.

Fecal microbiota composition affects in vitro fermentation of rye, oat, and wheat bread.

Fermentation of dietary fiber by gut microbes produces short-chain fatty acids (SCFA), but fermentation outcomes are affected by dietary fiber source and microbiota composition. The aim of this study was to investigate the effect of two different fecal microbial compositions on in vitro fermentation of a standardized amount of oat, rye, and wheat breads. Two human fecal donors with different microbial community composition were recruited. Bread samples were digested enzymatically. An in vitro fermentation model was used to study SCFA production, dietary fiber degradation, pH, and changes in microbiota. Feces from donor I had high relative abundance of Bacteroides and Escherichia/Shigella, whereas feces from donor II were high in Prevotella and Subdoligranulum. Shifts in microbiota composition were observed during fermentation. SCFA levels were low in the samples with fecal microbiota from donor I after 8 h of fermentation, but after 24 h acetate and propionate levels were similar in the samples from the different donors. Butyrate levels were higher in the fermentation samples from donor II, especially with rye substrate, where high abundance of Subdoligranulum was observed. Dietary fiber degradation was also higher in the fermentation samples from donor II. In conclusion, fermentation capacity and substrate utilization differed between the two different microbiota compositions.

Subcellular compartmentalization of aluminum reduced its hazardous impact on rye photosynthesis.

Aluminum (Al) toxicity limits crops growth and production in acidic soils. Compared to roots, less is known about the toxic effects of Al in leaves. Al subcellular compartmentalization is also largely unknown. Using rye (Secale cereale L.) Beira (more tolerant) and RioDeva (more sensitive to Al) genotypes, we evaluated the patterns of Al accumulation in leaf cell organelles and the photosynthetic and metabolic changes to cope with Al toxicity. The tolerant genotype accumulated less Al in all organelles, except the vacuoles. This suggests that Al compartmentalization plays a role in Al tolerance of Beira genotype. PSII efficiency, stomatal conductance, pigment biosynthesis, and photosynthesis metabolism were less affected in the tolerant genotype. In the Calvin cycle, carboxylation was compromised by Al exposure in the tolerant genotype. Other Calvin cycle-related enzymes, phoshoglycerate kinase (PGK), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), triose-phosphate isomerase (TPI), and fructose 1,6-bisphosphatase (FBPase) activities decreased in the sensitive line after 48 h of Al exposure. Consequentially, carbohydrate and organic acid metabolism were affected in a genotype-specific manner, where sugar levels increased only in the tolerant genotype. In conclusion, Al transport to the leaf and compartmentalization in the vacuoles tolerant genotype's leaf cells provide complementary mechanisms of Al tolerance, protecting the photosynthetic apparatus and thereby sustaining growth.

Bioaccessibility of Plant Sterols in Wholemeal Rye Bread Using the INFOGEST Protocol: Influence of Oral Phase and Enzymes of Lipid Metabolism.

Bioaccessibility of plant sterols (PS) in an enriched wholemeal rye bread was evaluated, for the first time, using the INFOGEST protocol without gastric lipase (GL) and cholesterol esterase (CE), with GL or GL + CE. Moreover, human chewing and an in vitro oral phase (simulated salivary fluid and α-amylase) were evaluated for this purpose. The addition of GL decreased the bioaccessibility of total PS (from 23.8 to 18.5%), whereas the use of GL + CE does not significantly affect PS bioaccessibility. The in vitro oral phase resulted in an ineffective homogenization of the fresh vs partially dried and milled bread, reducing the bioaccessibility of total (from 20.2 to 12.8%) and individual PS. The INFOGEST digestion including the use of GL and CE, as well as an oral phase with human chewing, is proposed for the assessment of PS bioaccessibility in a solid matrix such as wholemeal rye bread since it more closely approximates the in vivo situation.

Effects of particle size and phytase supplementation on apparent and standardized total tract digestibility of phosphorus in hybrid rye fed to growing pigs.

An experiment was conducted to investigate the effects of particle size (PS) and levels of phytase supplementation on the apparent (ATTD) and standardized (STTD) total tract digestibility of P in hybrid rye fed to growing pigs. Thirty-six growing barrows (23.6 ± 1.5 kg initial BW) were individually housed in metabolism crates and randomly allotted to one of six dietary treatments to give six replicates per treatment. The six dietary treatments were arranged in a 2 × 3 factorial with main effects of PS and phytase supplementation levels (0, 500, or 2,500 FTU/kg). Hybrid rye was ground using a hammermill mounted with 4.0- and 3.2-mm screens to obtain material with coarse and fine PS, respectively. Pigs were fed experimental diets for 11 d, including 5 d for adaptation and 6 d for total collection of feces. All data were analyzed using the MIXED procedure of SAS with PS, phytase, and their interaction as fixed effects. Orthogonal polynomial contrasts were used to test linear and quadratic effects of phytase level in both coarse and fine hybrid rye diets. The ATTD and STTD of P were greater (P < 0.05) in diets with fine than in those with coarse hybrid rye. Increasing levels of phytase supplementation linearly (P < 0.01) and quadratically (P < 0.01) improved the ATTD and STTD of P in hybrid rye diets. There were no interaction effects between PS and phytase supplementation on the ATTD and STTD of P in hybrid rye diets. In conclusion, PS reduction improved the digestibility of P in hybrid rye, and supplementing increasing levels of phytase improved P digestibility in linear and quadratic manner in growing pigs fed hybrid rye diets.

Cereal grains such as corn, wheat, and barley are widely used as an energy source in swine diets. However, due to their recent soaring prices, it is necessary to use alternative feedstuffs for swine. New commercial hybrid rye with improved ergot resistance and higher yield has been developed. This hybrid rye contains similar energy content as barley and sorghum, making it a promising ingredient for pigs. Phosphorus is an essential nutrient in swine diets for bone growth and cellular functions. However, most phosphorus in hybrid rye is bound to phytic acid, which is not digested well by pigs. The excessive phosphorus in swine manure may runoff and cause environmental problems such as eutrophication. Increasing phosphorus digestibility can decrease its excretion in pigs. Therefore, in the current study, we formulated six diets including fine or coarse hybrid rye particle size supplemented with three levels of phytase to determine the effects of particle size and phytase supplementation on phosphorus digestibility in hybrid rye. Our results showed that fine particle size and supplementing increasing levels of phytase could improve the phosphorus digestibility in growing pigs fed hybrid rye diets.

Dynamics of cell wall polysaccharides during the elongation growth of rye primary roots.

MAIN CONCLUSION: In cells of growing rye roots, xyloglucans and homogalacturonans demonstrate developmental stage specificity, while different xylans have tissue specificity. Mannans, arabinans and galactans are also detected within the protoplast. Mannans form films on sections of fresh material. The primary cell walls of plants represent supramolecular exocellular structures that are mainly composed of polysaccharides. Cell wall properties and architecture differ between species and across tissues within a species. We revised the distribution of cell wall polysaccharides and their dynamics during elongation growth and histogenesis in rye roots using nonfixed material and the spectrum of antibodies. Rye is a member of the Poaceae family and thus has so-called type II primary cell walls, which are supposed to be low in pectins and xyloglucans and instead have arabinoxylans and mixed-linkage glucans. However, rye cell walls at the earliest stages of cell development were enriched with the epitopes of xyloglucans and homogalacturonans. Mixed-linkage glucan, which is often considered an elongation growth-specific polysaccharide in plants with type II cell walls, did not display such dynamics in rye roots. The cessation of elongation growth and even the emergence of root hairs were not accompanied by the disappearance of mixed-linkage glucans from cell walls. The diversity of xylan motifs recognized by different antibodies was minimal in the meristem zone of rye roots, but this diversity increased and showed tissue specificity during root growth. Antibodies specific for xyloglucans, galactans, arabinans and mannans bound the cell content. When rye root cells were cut, the epitopes of xyloglucans, galactans and arabinans remained within the cell content, while mannans developed net-like or film-like structures on the surface of sections.

Use of the ß-Glucan-Producing Lactic Acid Bacteria Strains Levilactobacillus brevis and Pediococcus claussenii for Sourdough Fermentation-Chemical Characterization and Chemopreventive Potential of In Situ-Enriched Wheat and Rye Sourdoughs and Breads.

The aim of the present study was to examine ß-glucan production and the potential prebiotic and chemopreventive effects of wheat and rye sourdoughs and breads generated with wild-type and non-ß-glucan-forming isogenic mutant strains of Levilactobacillus brevis and Pediococcus claussenii. Sourdough and bread samples were subjected to in vitro digestion and fermentation. Fermentation supernatants (FS) and pellets (FP) were analyzed (pH values, short-chain fatty acids (SCFA), ammonia, bacterial taxa) and the effects of FS on LT97 colon adenoma cell growth, viability, caspase-2 and -3 activity, genotoxic and antigenotoxic effects and on gene and protein expression of p21, cyclin D2, catalase and superoxide dismutase 2 (SOD2) were examined. Concentrations of SCFA were increased and concentrations of ammonia were partly reduced in the FS. The relative abundance of Bifidobacteriaceae was increased in all FPs. Treatment with FS reduced the growth and viability of LT97 cells and significantly increased caspase-2 and -3 activities without exhibiting genotoxic or antigenotoxic effects. The p21 mRNA and protein levels were increased while that of cyclin D2 was reduced. Catalase and SOD2 mRNA and protein expression were marginally induced. The presented results indicate a comparable chemopreventive potential of wheat and rye sourdoughs and breads without an additional effect of the formed ß-glucan.

Association mapping of autumn-seeded rye (Secale cereale L.) reveals genetic linkages between genes controlling winter hardiness and plant development.

Winter field survival (WFS) in autumn-seeded winter cereals is a complex trait associated with low temperature tolerance (LTT), prostrate growth habit (PGH), and final leaf number (FLN). WFS and the three sub-traits were analyzed by a genome-wide association study of 96 rye (Secale cereal L.) genotypes of different origins and winter-hardiness levels. A total of 10,244 single nucleotide polymorphism (SNP) markers were identified by genotyping by sequencing and 259 marker-trait-associations (MTAs; p < 0.01) were revealed by association mapping. The ten most significant SNPs (p < 1.49e-04) associated with WFS corresponded to nine strong candidate genes: Inducer of CBF Expression 1 (ICE1), Cold-regulated 413-Plasma Membrane Protein 1 (COR413-PM1), Ice Recrystallization Inhibition Protein 1 (IRIP1), Jasmonate-resistant 1 (JAR1), BIPP2C1-like protein phosphatase, Chloroplast Unusual Positioning Protein-1 (CHUP1), FRIGIDA-like 4 (FRL4-like) protein, Chalcone Synthase 2 (CHS2), and Phenylalanine Ammonia-lyase 8 (PAL8). Seven of the candidate genes were also significant for one or several of the sub-traits supporting the hypothesis that WFS, LTT, FLN, and PGH are genetically interlinked. The winter-hardy rye genotypes generally carried additional allele variants for the strong candidate genes, which suggested allele diversity was a major contributor to cold acclimation efficiency and consistent high WFS under varying field conditions.

An inverse association between plasma benzoxazinoid metabolites and PSA after rye intake in men with prostate cancer revealed with a new method.

Prostate cancer (PC) is a common cancer among men, and preventive strategies are warranted. Benzoxazinoids (BXs) in rye have shown potential against PC in vitro but human studies are lacking. The aim was to establish a quantitative method for analysis of BXs and investigate their plasma levels after a whole grain/bran rye vs refined wheat intervention, as well as exploring their association with PSA, in men with PC. A quantitative method for analysis of 22 BXs, including novel metabolites identified by mass spectrometry and NMR, was established, and applied to plasma samples from a randomized crossover study where patients with indolent PC (n = 17) consumed 485 g whole grain rye/rye bran or fiber supplemented refined wheat daily for 6 wk. Most BXs were significantly higher in plasma after rye (0.3-19.4 nmol/L in plasma) vs. refined wheat (0.05-2.9 nmol/L) intake. HBOA-glc, 2-HHPAA, HBOA-glcA, 2-HPAA-glcA were inversely correlated to PSA in plasma (p < 0.04). To conclude, BXs in plasma, including metabolites not previously analyzed, were quantified. BX metabolites were significantly higher after rye vs refined wheat consumption. Four BX-related metabolites were inversely associated with PSA, which merits further investigation.

Characterization of gliadin, secalin and hordein fractions using analytical techniques.

Prolamins, alcohol soluble storage proteins of the Triticeae tribe of Gramineae family, are known as gliadin, secalin and hordein in wheat, rye and barley respectively. Prolamins were extracted from fifteen cultivars using DuPont protocol to study their physiochemical, morphological and structural characteristics. SDS-PAGE of prolamins showed well resolved low molecular weight proteins with significant amount of albumin and globulin as cross-contaminant. The ß-sheet (32.72-37.41%) and ß-turn (30.36-37.91%) were found higher in gliadins, while α-helix (20.32-28.95%) and random coil (9.05-10.28%) in hordeins. The high colloidal stability as depicted by zeta-potential was observed in gliadins (23.5-27.0 mV) followed secalins (11.2-16.6 mV) and hordeins (4.1-7.8 mV). Surface morphology by SEM illustrated the globular particle arrangement in gliadins, sheet like arrangement in secalins and stacked flaky particle arrangement in hordeins fraction. TEM studies showed that secalin and hordein fractions were globular in shape while gliadins in addition to globular structure also possessed rod-shaped particle arrangement. XRD pattern of prolamin fractions showed the ordered crystalline domain at 2θ values of 44.1°, 37.8° and 10.4°. The extracted prolamins fractions showed amorphous as well as crystalline structures as revealed by XRD and TEM analysis. Space saving hexagonal molecular symmetry was also observed in TEM molecular arrangement of prolamins which has profound application in development of plant-based polymers and fibres.

A mechanistic view on lodging resistance in rye and wheat: a multiscale comparative study.

The development of crop varieties that are resistant to lodging is a top priority for breeding programmes. Herein, we characterize the rye mutant ´Stabilstroh' ('stable straw') possessing an exceptional combination of high lodging resistance, tall posture and high biomass production. Nuclear magnetic resonance imaging displayed the 3-dimensional assembly of vascular bundles in stem. A higher number of vascular bundles and a higher degree of their incline were the features of lodging-resistant versus lodging-prone lines. Histology and electron microscopy revealed that stems are fortified by a higher proportion of sclerenchyma and thickened cell walls, as well as some epidermal invaginations. Biochemical analysis using Fourier-transform infrared spectroscopy and inductively coupled plasma-optical emission spectrometry further identified elevated levels of lignin, xylan, zinc and silicon as features associated with high lodging resistance. Combined effects of above features caused superior culm stability. A simplistic mathematical model showed how mechanical forces distribute within the stem under stress. Main traits of the lodging-resistant parental line were heritable and could be traced back to the genetic structure of the mutant. Evaluation of lodging-resistant wheat 'Babax' ('Baviacora') versus contrasting, lodging-prone, genotype ´Pastor´ agreed with above findings on rye. Our findings on mechanical stability and extraordinary culm properties may be important for breeders for the improvement of lodging resistance of tall posture cereal crops.

The rye transcription factor ScSTOP1 regulates the tolerance to aluminum by activating the ALMT1 transporter.

Plants have evolved different mechanisms to increase their tolerance to aluminum (Al) toxicity and low pH in the soil. The Zn finger transcription factor SENSITIVE TO PROTON RHIZOTOXICITY1 (STOP1) plays an essential role in the adaptation of plants to Al and low pH stresses. In this work, we isolated the ScSTOP1 gene from rye (Secale cereale L.), which is located on chromosome 3RS. The ectopic expression of ScSTOP1 complements the Arabidopsis stop1 mutation in terms of root growth inhibition due to Al and pH stress, as well as phosphate starvation tolerance, suggesting that rye ScSTOP1 is a functional ortholog of AtSTOP1. A putative STOP1 binding motif was identified in the promoter of a well-known STOP1 target from rye and Arabidopsis and was later corroborated by genomic DAP-seq analyses. Coexpression analyses verified that ScSTOP1 activated the promoter of ScALMT1. We have also identified a putative phosphorylatable serine in STOP1 that is phylogenetically conserved and critical for such activation. Our data indicated that ScSTOP1 also regulated Al and pH tolerance in rye.

Mass spectrometry-based metabolomics unravel the transfer of bioactive compounds between rye and neighbouring plants.

Translocation of metabolites between different plant species provides important hints in understanding the fate of bioactive root exudates. In the present study, targeted and untargeted mass spectrometry-based metabolomics was applied to elucidate the transfer of bioactive compounds between rye and several crops and weed species. Our results demonstrated that benzoxazinoids (BXs) synthesized by rye were taken up by roots of neighbouring plant species and translocated into their shoots. Furthermore, we showed that roots of rye plants took up compounds originating from neighbouring plants. Among the compounds taken up by rye roots, wogonin was detected in the rye shoot, which indicated a root-to-shoot translocation of this compound. Elucidating the transfer of bioactive compounds between plants is essential for understanding plant-plant interactions, developing natural pesticides and understanding their modes of action.

The Roots of Rye (Secale cereale L.) Are Capable of Synthesizing Benzoxazinoids.

According to current opinion, the first step of benzoxazinoids (BXs) synthesis, that is, the conversion of indole-3-glycerol phosphate to indole, occurs exclusively in the photosynthesising parts of plants. However, the results of our previous work and some other studies suggest that this process may also occur in the roots. In this study, we provide evidence that the first step of BXs synthesis does indeed occur in the roots of rye seedlings. We detected ScBx1 transcripts, BX1 enzyme, and six BXs (2-hydroxy-1,4-benzoxazin-3-one, 2,4-dihydroxy-1,4-benzoxazin-3-one, (2R)-2-O-ß-d-glucopyranosyl-4-hydroxy-(2H)-1,4-benzoxazin-3(4H)-one glucoside, 2,4-dihydroxy- 7-methoxy-1,4-benzoxazin-3-one, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one glucoside, and 6-methoxy-2-benzoxazolinone) in the roots developed from seeds deprived of the coleoptile at 2 days after sowing (i.e., roots without contact with aerial parts). In roots regenerated in vitro, both ScBx1 transcripts and BX1 enzyme were detected at a low but still measurable levels. Thus, BXs are able to be synthesised in both the roots and above-ground parts of rye plants.

Ph2 encodes the mismatch repair protein MSH7-3D that inhibits wheat homoeologous recombination.

Meiotic recombination is a critical process for plant breeding, as it creates novel allele combinations that can be exploited for crop improvement. In wheat, a complex allohexaploid that has a diploid-like behaviour, meiotic recombination between homoeologous or alien chromosomes is suppressed through the action of several loci. Here, we report positional cloning of Pairing homoeologous 2 (Ph2) and functional validation of the wheat DNA mismatch repair protein MSH7-3D as a key inhibitor of homoeologous recombination, thus solving a half-century-old question. Similar to ph2 mutant phenotype, we show that mutating MSH7-3D induces a substantial increase in homoeologous recombination (up to 5.5 fold) in wheat-wild relative hybrids, which is also associated with a reduction in homologous recombination. These data reveal a role for MSH7-3D in meiotic stabilisation of allopolyploidy and provides an opportunity to improve wheat's genetic diversity through alien gene introgression, a major bottleneck facing crop improvement.

Effect of alkyl chain length on the antioxidant activity of alkylresorcinol homologues in bulk oils and oil-in-water emulsions.

The antioxidant cut-off theory details the importance of fine-tuning antioxidant hydrophobicity to optimize antioxidant effectiveness for a given food system; however, previous research has utilized synthetic antioxidant homologues which fail to align with the food industry's demand for natural ingredients. Alkylresorcinols represent a natural homologous series of phenolipid antioxidants. The antioxidant activities of individual alkylresorcinol homologues were investigated in bulk oils and oil-in-water emulsions. In oils, antioxidant activity decreased as alkyl chain length increased and there was no effect on rate of loss. In emulsions, optimum antioxidant activity was observed at intermediate alkyl chain length (C21:0) and longer homologues were lost more rapidly. Radical scavenging capacity decreased as alkyl chain length increased but alkylresorcinols were unable to chelate iron. This suggests that intrinsic properties (e.g. radical scavenging capacity) are responsible for the antioxidant activity of alkylresorcinols in oils while physicochemical phenomena (e.g. partitioning) drive antioxidant activity of alkylresorcinols in emulsions.

Heat and hydrothermal treatments of non-wheat flours.

Non-wheat cereals have become popular in the diet due to their nutritional benefits, but their application is limited by properties of their proteins. Some of these flours can be conventionally processed, but the final products are not of acceptable quality. Modification of physico-chemical properties of non-wheat flours by dry heat and extrusion represent the alternative process which can transform the flours into an adequate raw material for the bakery and confectionery industry. The aim of this study was to determine the type and extent of physico-chemical changes in modified flours whose mixtures were used successfully for bread production. Extrusion had stronger influence on chemical composition of flours than dry heating, especially on the content of fats and phenolic compounds. Extrusion also increased starch digestibility due to complete gelatinization process, making it almost equal for all flours. On the other hand, protein digestibility depends mostly on botanical origin of flour.

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.