Development of gluten-free craft beer: Impact of brewing process on quality attributes and consumer expectations for sensory properties.

To date, few studies investigated the differences between the two main gluten-free (GF) brewing techniques, such as the use of enzymes and the use of unconventional GF grains in brewing, by consumer perspective. In this study a GF beer brewed with sorghum and quinoa, as brewing adjuncts, was compared to the enzymatic-treated counterpart, in order to evaluate the effect of deglutinization treatment on physicochemical, volatile, and sensory characteristics of final beer. Moreover, the influence of brewing process and raw materials information on consumers' sensory perceptions, willingness to buy (WTB) and willingness to pay (WTP) was also investigated (n = 105 consumers), under blind (B), expected (E), and informed (I) conditions. The enzymatic-treated sample showed comparable physicochemical attributes with the untreated counterpart, except for a significant reduction in color and foam stability (p < 0.05). Non-significant difference between samples was found in the overall liking, WTB, and WTP mean scores in all three sensory test conditions (p > 0.05). The information about the deglutinization treatment had a negative impact on overall liking (p < 0.01), although WTP for both samples was significantly higher in the informed test than in blind condition (p < 0.05). Overall, Check-All-That-Apply test results confirmed that the deglutinization treatment does not affect the beer sensory profile, even if the information about brewing ingredients and technologies may slightly influence the consumers' sensory perception. Therefore, this result proves that it is possible to produce a marketable GF beer, simply by partially replacing 40% of barley malt with unconventional GF grains, without using enzymes for gluten reduction purpose.

Assessment of brewing attitude of unmalted cereals and pseudocereals for gluten free beer production.

In this study, 40% of unmalted gluten free (GF) grains (sorghum, millet, buckwheat, quinoa and amaranth) was used in brewing process, in gelatinized and ungelatinized form, in order to produce GF beer and to extend current knowledge about their suitability as brewing adjuncts. Partial replacement of barley malt with GF grains led to a significant decrease of extract (°P) and alcohol (%v/v) content compared to control beer (p < 0.05), except for quinoa beer (QB). Results from Principal Component Analysis (PCA) highlighted a satisfactory classification of experimental beers according to the two different forms of GF grains (gelatinized and ungelatinized). However, beers brewed with ungelatinized grains (mainly sorghum and quinoa) showed acceptable technological and sensory properties, thus suggesting that the pre-gelatinization step could be bypassed with a view to more environmentally and economically sustainable time-saving process. In addition, all beer samples showed a gluten content higher than 20 ppm.

Non-conventional yeasts from fermented honey by-products: Focus on Hanseniaspora uvarum strains for craft beer production.

The increasing interest in novel beer productions focused on non-Saccharomyces yeasts in order to pursue their potential in generating groundbreaking sensory profiles. Traditional fermented beverages represent an important source of yeast strains which could express interesting features during brewing. A total of 404 yeasts were isolated from fermented honey by-products and identified as Saccharomyces cerevisiae, Wickerhamomyces anomalus, Zygosaccharomyces bailii, Zygosaccharomyces rouxii and Hanseniaspora uvarum. Five H. uvarum strains were screened for their brewing capability. Interestingly, Hanseniaspora uvarum strains showed growth in presence of ethanol and hop and a more rapid growth than the control strain S. cerevisiae US-05. Even though all strains showed a very low fermentation power, their concentrations ranged between 7 and 8 Log cycles during fermentation. The statistical analyses showed significant differences among the strains and underlined the ability of YGA2 and YGA34 to grow rapidly in presence of ethanol and hop. The strain YGA34 showed the best technological properties and was selected for beer production. Its presence in mixed- and sequential-culture fermentations with US-05 did not influence attenuation and ethanol concentration but had a significant impact on glycerol and acetic acid concentrations, with a higher sensory complexity and intensity, representing promising co-starters during craft beer production.

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.

High genetic and chemical diversity of wild hop populations from Central Italy with signals of a genetic structure influenced by both sexual and asexual reproduction.

In order to investigate the intraspecific diversity of wild Humulus lupulus (hop) in Central Italy, 12 populations were evaluated for their genetic polymorphism by means of 13 SSR loci together with six commercial cultivars as a reference. High levels of polymorphism were found across the populations, being 140 the number of multilocus genotypes over 159 samples analyzed. Moreover, the observed heterozygosity was higher than expected in most of the populations. High levels of gene flow were thus envisaged to occur within and among wild populations, and our sampling strategy allowed us to gain insights on the propagation modes of this species, i.e. clonal versus sexual propagation. Nevertheless, a genetic structure of populations with at least five genetically different clusters was disclosed. Private alleles were observed in both wild and cultivated hops. Chemical analysis of bittering and aromatic quality of female flowers from a subset of 8 wild populations revealed a high variability among plants, especially for essential oil components. Overall, the high variability of wild accessions here examined represent a valid source to be exploited in future breeding programs for new or improved hop cultivars development.

Brewing By-Product Upcycling Potential: Nutritionally Valuable Compounds and Antioxidant Activity Evaluation.

The brewing industry produces high quantities of solid and liquid waste, causing disposal issues. Brewing spent grains (BSGs) and brewing spent hop (BSH) are important by-products of the brewing industry and possess a high-value chemical composition. In this study, BSG and BSH, obtained from the production process of two different types of ale beer (Imperial red and Belgian strong beer) were characterized in terms of valuable components, including proteins, carbohydrates, fat, dietary fiber, ß-glucans, arabinoxylans, polyphenols, and phenolic acids, and antioxidant activity (Ferric Reducing Antioxidant Power Assay (FRAP), 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS)). Significant concentrations of total polyphenols were observed in both BSH and BSG samples (average of about 10 mg GAE/g of dry mass); however, about 1.5-fold higher levels were detected in by-products of Belgian strong ale beer compared with Imperial red. Free and bound phenolic acids were quantified using a validated chromatographic method. A much higher level of total phenolic acids (TPA) (about 16-fold higher) was found in BSG samples compared with BSHs. Finally, their antioxidant potential was verified. By-products of Belgian strong ale beer, both BSG and BSH, showed significantly higher antioxidative capacity (about 1.5-fold lower inhibitory concentration (IC50) values) compared with spent grains and hop from the brewing of Imperial red ale. In summary, BSG and BSH may be considered rich sources of protein, carbohydrates, fiber, and antioxidant compounds (polyphenols), and have the potential to be upcycled by transformation into value-added products.

Comparison of carbohydrate partitioning and expression patterns of some genes involved in carbohydrate biosynthesis pathways in annual and biennial species of Cichorium spp.

Variation in metabolism and partitioning of carbohydrates, particularly fructans, between annual and perennial Cichorium species remains a challenging topic. To address this problem, an annual (endive, Cichorium endive L. var. Crispum; Asteraceae) and a biennial species (chicory, Cichorium intybus L. var. Witloof; Asteraceae) were compared with in terms of variability in carbohydrate accumulation and expression patterns of fructan-active enzyme genes, as well as sucrose metabolism at various growth and developmental stages. In general, constituents such as 1-kestose, nystose, and inulin were detected only in the root of chicory and were not present in any of the endive tissues. For both species, flower tissue contained maximum levels of both fructose and glucose, while for sucrose, more fluctuations were observed. On the other hand, all the genes under study exhibited variation, not only between the two species but also among different tissues at different sampling times. In endive root compared to endive leaf, the expression of cell wall invertase genes and sucrose accumulation decreased simultaneously, indicating the limited capacity of its roots to absorb sucrose, a precursor to inulin production. In addition, low expression of fructan: fructan fructosyltransferase in endive root compared to chicory root confirmed the inability of endive to inulin synthesis. Overall, annual and biennial species were different in the production of inulin, transport, remobilization, and unloading of sucrose.

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.

Effect of Baking Time and Temperature on Nutrients and Phenolic Compounds Content of Fresh Sprouts Breadlike Product.

Sprouting has received increasing attention because of the enhanced nutritional values of the derived products. Baking affects the nutrient availability of the end products. The aim of this study was to evaluate how different baking time and temperature affect the nutritional values of bakery products derived from fresh wheat sprouts. Results indicate that the breadlike products showed comparable total polyphenol content and the thermal processes affected the free and bound fractions. Low temperature and high exposure time appear to promote the availability of the free polyphenols and sugars, while high temperature and low exposure time appear to preserve bound polyphenols and starch. Sugar profiles were influenced by baking programs with a higher simple sugar content in the samples processed at low temperature. Phenolic acids showed a strong decrease following processing, and free and bound phenolic acids were positively influenced by high baking temperatures, while an opposite trend was detected at low temperatures. Significant differences in phenolic acid profiles were also observed with a redistribution of hydroxycinnamic acids among the bound and free fractions. It may be concluded that grain type, germination conditions, and the baking programs play a fundamental role for the production of high-nutritional-value bakery products.

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.

Accelerated shelf-life model of gluten-free rusks by using oxidation indices.

The demand for gluten-free products has been growing over the last few years as is the need to improve their quality. The objective of this research was to develop a shelf life prediction model of gluten-free rusks. To this aim, a kinetic study of the primary and secondary oxidative process was run and the kinetic parameters (rate constant, activation energy, and temperature quotient) were calculated. The protective effect of the antioxidant included in the recipe was also evaluated, and the prediction model was applied to predict the shelf life of an experimental batch of gluten-free rusks with a lower content of antioxidant. The results highlighted (i) the reliability of the prediction model and (ii) the effectiveness of the antioxidant in reducing the rate of primary oxidation. Moreover, (iii) a possible hexanal threshold (lower than 121 µg/kg), correlated with rancid perception in gluten-free rusks, was also speculated.

Characterization of Defatted Products Obtained from the Parmigiano-Reggiano Manufacturing Chain: Determination of Peptides and Amino Acids Content and Study of the Digestibility and Bioactive Properties.

Parmigiano-Reggiano (PR) is a worldwide known Italian, long ripened, hard cheese. Its inclusion in the list of cheeses bearing the protected designation of origin (PDO, EU regulation 510/2006) poses restrictions to its geographic area of production and its technological characteristics. To innovate the Parmigiano-Reggiano (PR) cheese manufacturing chain from the health and nutritional point of view, the output of defatted PR is addressed. Two defatting procedures (Soxhlet, and supercritical CO2 extraction) were tested, and the obtained products were compared in the composition of their nitrogen fraction, responsible for their nutritional, organoleptic, and bioactive functions. Free amino acids were quantified, and other nitrogen compounds (peptides, proteins, and non-proteolytic aminoacyl derivatives) were identified in the extracts and the mixtures obtained after simulated gastrointestinal digestion. Moreover, antioxidant and angiotensin converting enzyme (ACE) inhibition capacities of the digests were tested. Results obtained from the molecular and biofunctional characterization of the nitrogen fraction, show that both the defatted products keep the same nutritional properties of the whole cheese.

Effects of Growth Conditions and Cultivar on the Content and Physiochemical Properties of Arabinoxylan in Barley.

The present study aims to evaluate the effect of the growth conditions and the cultivar on the total and water-extractable (W-E) arabinoxylan (AX) in barley. For this purpose, nine barley varieties from two different years were analyzed. The total AX content ranged from 5.97 to 8.98 wt % d.m., while the W-E AX ranged from 0.06 to 0.35 wt % d.m. The W-E AX molecular properties were characterized by high-pressure size exclusion chromatography (HPSEC)-triple detector array (TDA). The molecular weight was between 2.3 × 105 and 12.6 × 105 Da, the polydispersity was between moderate and broad (1.1 < Mw/Mn < 4.3), and the conformation was a stiff semiflexible coil (0.5 < α < 1.3). The results indicate that the year influences the content of total AX and W-E AX and some molecular characteristics of W-E AX, such as its polydispersity and its conformation. Finally, the results demonstrated that the W-E AX can be used as an index of the malting attitude of barley because it positively correlates with germinative energy and kernel dimension.

Effect of Growth Conditions and Genotype on Barley Yield and ß-Glucan Content of Kernels and Malt.

This study was conducted to evaluate the effect of growth conditions and genotype on the barley yield and ß-glucan content of grain and malt. Total and water-extractable (W-E) ß-glucans and their molecular and structural properties were analyzed in nine 2-row barley varieties and corresponding malts. The total ß-glucan content of barley is not influenced by year or by the cultivar, while the grain yield and W-E ß-glucan content are significantly influenced by the year. Barley W-E ß-glucans have a molecular weight between 1.0 × 105 and 4.0 × 105 Da and a random coil conformation. ß-Glucan levels in malt are significantly lower than in barley, and neither the total nor the W-E ß-glucans are influenced by environmental factors or genetic aspects. W-E ß-glucans are mainly composed of fractions with Mw values below 1.0 × 105 Da. In conclusion, the molecular characterization of ß-glucans could represent a powerful tool to understand their role in the brewing process.

Rice malting optimization for the production of top-fermented gluten-free beer.

BACKGROUND: A safe method to obtain gluten-free beer led to the use of naturally gluten-free grains, such as rice, but the specific malting program for rice is long and requires a large amount of water, and the resulting beer showed a flat flavour profile. In this study, an optimization of the malting and brewing procedure is proposed to overcome the aforementioned issues. Different steeping conditions and kilning temperatures are considered, and a top-fermented beverage from rice malt is obtained for the first time. RESULTS: The malting procedure has been optimized by assessing the use of short-time steeping as an alternate to long air rest to obtain sufficient moisture content in the green malt, saving water consumption. The malt obtained allowed a regular fermentation, as confirmed by the sensorial analysis, which did not reveal any off-flavours. The use of a top-fermenting yeast formed high content of higher alcohol and relatively low amount of esters. CONCLUSION: This study confirms the potential of rice for the production of malt and beer. The optimized malting programme allowed water saving. The production of a top-fermented rice malt beer was a successful attempt to introduce a new flavoured product for consumption by individuals affected by coeliac disease. © 2018 Society of Chemical Industry.

Germination under Moderate Salinity Increases Phenolic Content and Antioxidant Activity in Rapeseed (Brassica napus var oleifera Del.) Sprouts.

The use of sprouts in the human diet is becoming more and more widespread because they are tasty and high in bioactive compounds and antioxidants, with related health benefits. In this work, we sprouted rapeseed under increasing salinity to investigate the effect on free and bound total phenolics (TP), non-flavonoids (NF), tannins (TAN), phenolic acids (PAs), and antioxidant activity. Seeds were incubated at 0, 25, 50, 100, 200 mM NaCl until early or late sprout stage, i.e., before or after cotyledon expansion, respectively. Sprouting and increasing salinity slightly decreased the bound fractions of TP, NF, TAN, PAs, while it increased markedly the free ones and their antioxidant activity. Further increases were observed in late sprouts. Moderate salinity (25-50 mM NaCl) caused the highest relative increase in phenolic concentration while it slightly affected sprout growth. On the contrary, at higher NaCl concentrations, sprouts grew slowly (100 mM NaCl) or even died before reaching the late sprout stage (200 mM). Overall, moderate salinity was the best compromise to increase phenolic content of rapeseed sprouts. The technique may be evaluated for transfer to other species as a cheap and feasible way to increase the nutritional value of sprouts.

Gluten-Free Sources of Fermentable Extract: Effect of Temperature and Germination Time on Quality Attributes of Teff [Eragrostis tef (zucc.) Trotter] Malt and Wort.

This study was conducted to evaluate the behavior of a white teff variety called Witkop during malting by using different parameters (germination temperature and duration) and to identify the best malting program. Samples were evaluated for standard quality malt and wort attributes, pasting characteristics, ß-glucan and arabinoxylan content, and sugar profile. It was concluded that malting teff at 24 °C for 6 days produced acceptable malt in terms of quality attributes and sugar profile for brewing. The main attributes were 80.4% extract, 80.9% fermentability, 1.53 mPa s viscosity, 7.4 EBC-U color, 129 mg/L FAN, and 72.1 g/L of total fermentable sugars. Statistical analysis showed that pasting characteristics of teff malt were negatively correlated with some malt quality attributes, such as extract and fermentability. Witkop teff appeared to be a promising raw material for malting and brewing. However, the small grain size may lead to difficulties in handling malting process, and a bespoke brewhouse plant should be developed for the production at industrial scale.

Antioxidant effects of supercritical fluid garlic extracts in sunflower oil.

BACKGROUND: Lipid oxidation causes changes in quality attributes of vegetable oils. Synthetic antioxidants have been used to preserve oils; however, there is interest in replacing them with natural ones. Garlic and its thiosulfinate compound allicin are known for their antioxidant activities. This study assesses a novel formulation, the supercritical fluid extract of garlic, on sunflower oil oxidation during an accelerated shelf-life test. RESULTS: Three quality parameters (free acidity, peroxide values, and p-anisidine values) were evaluated in each of the six oil samples. The samples included sunflower oil alone, sunflower oil supplemented with BHT, the undiluted supercritical fluid extract of garlic, and sunflower oils supplemented with three levels of garlic extract. The oils were also investigated for their antioxidant properties using the DPPH and the FRAP assays. The results were compared with the effect of the synthetic BHT. Our results underlined that the highest level of garlic extract may be superior, or at least comparable, with BHT in preserving sunflower oil. CONCLUSION: The oxidative degradation of oily samples can be limited by using supercritical fluid extract of garlic as it is a safe and an effective natural antioxidant formulation. © 2016 Society of Chemical Industry.