Use of hop extract as antifungal ingredient for bread making and selection of autochthonous resistant starters for sourdough fermentation

Antimicrobial Packaging from Potato Starch and Pectin with Citric Acid and Bioactive Compounds from Cashew Apple: Preparation, Characterization, and Application in Bread

This study aimed to develop and characterize active antimicrobial films composed of potato starch and pectin, by incorporating inverted sugar as a plasticizer and bioactive compounds from cashew (CC) and citric acid (CA) as additives for application in bread packaging. Five treatments were formulated by the solution casting method: F0 (without CC-0.5% CA), F1 (1% CC-0.25% CA), F3 (3% CC-0.5% CA), F6 (6% CC-1% CA), and C1 (without CC and CA). Two other controls were used in the bread application (C2: low-density polyethylene and C3: unpackaged bread). Treatments with additives exhibited an increased water vapor permeability compared to C1; F6 showed the highest value (7.62 × 10-4 g H2O mm/m2 h mmHg). Conversely, C1 demonstrated superior tensile strength (21.13 MPa) compared to the other treatments, while films containing additives displayed heightened elongation (507.19%) relative to C1. Color parameters indicated a decrease in L* values (88.95), accompanied by an increase in a* (0.62) and b* (16.64) values for the high-concentration treatment (F6). Additionally, F6 degraded completely within 8 days. Therefore, the application of active films (F1 and F3) acted as antimicrobial packaging for bread, extending its microbiological stability 4-fold from 7 to 28 days. Future studies should explore the optimization of film formulations and their scalability for commercial applications.

Tailor-made fermentation of sprouted wheat and barley flours and their application in bread making: A comprehensive comparison with conventional approaches in the baking industry

This study investigates the development and application of type III sourdoughs, produced by fermenting sprouted wheat and barley flours with carefully selected lactic acid bacteria (LAB). Two optimized combinations of LAB strains were used: Furfurilactobacillus rossiae (CR5), Weissella confusa T6B10, and Lactiplantibacillus plantarum SB88.B4 for sprouted wheat flour; and Leuconostoc pseudomesenteroides DSM 20193, L. plantarum 7A, and F. rossiae (CR5) for sprouted barley flours. Fermentation resulted in substantial increases in peptide content (450 % in sprouted wheat flour-based sourdough and 520 % in sprouted barley flour-based sourdough) and phenolic compounds (344 % and 261 %, respectively), along with improved antioxidant activity (100 % in wheat and 40 % in barley). Among the experimental breads, those made with sprouted barley sourdough demonstrated the highest nutritional and functional benefits, including a highest content of dietary fiber, improved in vitro protein digestibility (IVPD, 81.14 %), a reduced predicted glycemic index (pGI, 84.78 %), and strong angiotensin-converting enzyme (ACE) inhibitory activity (73 %). The rheological behaviour of doughs incorporating novel type III sourdoughs was comparable to those containing type II wheat sourdoughs combined with enzymatyc enanchers, indicating their suitability for baking applications. Sensory evaluations highlighted that bread made with type III sourdough from sprouted wheat flour was appreciated for its enhanced crust and crumb colour, while bread made with sprouted barley sourdough stood out for its rich bran aroma, toasted notes, and balanced acidity. This study highlights the potential of targeted fermentation of sprouted flours as a key solution to address the growing demand for health-focused and eco-friendly innovations from both consumers and producers.

Effects of Cytokinins on Morphogenesis, Total (Poly)Phenolic Content and Antioxidant Capacity of In Vitro-Cultured Hop Plantlets, cvs. Cascade and Columbus

(1) Background: Humulus lupulus L. plants constitute a rich source of bioactive compounds. The synthesis of bioactive compounds in plants is often triggered by the activation of secondary metabolism, which can be induced by biotic or abiotic elicitors. In vitro, the effect of the elicitors can be studied in a controlled environment and in a small space, independently of seasonal variations. Cytokinins are frequently used in plant tissue culture for bud regeneration, branching and shoot elongation due to their role in cell division enhancement. This study aimed to investigate the effects of different cytokinins on the growth parameters, total (poly)phenolic content and antioxidant capacity of in vitro-grown hop plants to evaluate hop vitro-derived biomass as a potential source of bioactive compounds. (2) Methods: unimodal hop (cvs. Cascade and Columbus) explants were cultured on media enriched with four cytokinins (kinetin, 6-benzylaminopurine, meta-topolin and 6-(γ,γ-dimethylallylamino)-purine) at four concentrations. (3) Results: A genotype-dependent response to different cytokinins was encountered. (4) Conclusions Columbus explants could root in culture media auxin-free, providing valuable opportunities for commercial nurseries. Moreover, cytokinins were confirmed to be valuable elicitors to stimulate the bioactive compound biosynthesis in micropropagated hop plants, making them a precious source for various industries.

Hop leaves: From waste to a valuable source of bioactive compounds - A multidisciplinary approach to investigating potential applications

After harvesting of cones used for beer production, the remaining hop vegetative biomass requires disposal. The hop plant contains bioactive compounds in all its parts-cones, leaves, and roots-exhibiting interesting antioxidant, antiviral, and antibacterial properties. In this work, extracts obtained from hop leaves, a plant material often neglected in the hop cultivation, have been investigated; the qualitative UHPLC-MS/MS and GC-TOF-MS characterization revealed the presence of bioactive compounds such as polyphenols, α- and β-acids and terpenes are present. The extract retained antioxidant activity, as verified by Folin-Ciocalteu, DPPH, ABTS and FRAP assays, and demonstrated some antimicrobial activity when combined with antibiotics, particularly against Gram-positive bacterial strains. Additionally, the extracts showed an ability to interact with proteins as human insulin, amyloid beta peptide, mucin and bovine serum albumin (BSA), has been detected, indicating their potential to counteract inflammatory processes and protect against Alzheimer's disease. These findings suggest that hop vegetative biomass, typically considered waste, can be potentially transformed into a valuable resource with applications in various fields, from nutraceuticals to pharmaceuticals and cosmetics, aligning with a circular economy perspective.

Phytochemical, spectroscopic analysis and antifungal activity on bell peppers of hydrothermal bioactive metabolites of Humulus lupulus L. extracts

This study aimed to evaluate the impact of temperature on the potential extraction of bioactive compounds from aqueous hop extract samples. The main bioactive components were characterised and analysed by LC-MS/MS, FT-IR, phenolic compounds and total flavonoids. Antifungal activity was evaluated in vitro and in vivo in bell peppers. LC-MS/MS analysis demonstrated increases and decreases of bioactive compounds in both extracts depending on the extraction temperature of 25 or 65 °C. The bioactive compounds showed significant changes in the bands between 2786 to 3600 cm-1 and 1022 to 1729 cm-1 in the FT-IR spectrum. The highest antifungal activity against the microorganisms was observed in the EkuanotMT extract at an extraction temperature of 65 °C. The in vivo test with bell peppers presented antifungal activity during five days of evaluation under normal environmental conditions without refrigeration, presenting ≤ 52% of the disease due to F. oxysporum and A. solani.

Exploring the composition and potential uses of four hops varieties through different extraction techniques

Hydrophilic, lipophilic extracts and essential oil of four hops varieties from Slovenia were examined in this study. Lipophilic extracts were obtained by supercritical extraction (SFE), while for hydrophilic extracts ultrasound and microwave extraction were employed. Essential oils were isolated by the hydrodistillation process. The lipophilic composition of essential oils and lipophilic extracts was determined by GC-MS analysis. Monoterpenes and sesquiterpene hydrocarbons were the most abundant class of compounds in oils (62.27-79.65 %), with myrcene being the most abundant constituent. Limonene and trans-caryophyllene were two terpenes determined in all essential oils while only trans-caryophyllene was detected in SFE samples. Antioxidant, antimicrobial, and cytotoxic activity, determined by applying in vitro assays, was more influenced by extraction technique than by varieties. Molecular docking was carried out to gain insight into the potential cancer protein targets BCL-2 and MMP9, whereby humulene epoxide II displayed good binding configuration within the cavities of the two proteins.

Evaluation of In Vitro-Derived Hop Plantlets, cv. Columbus and Magnum, as Potential Source of Bioactive Compounds

The demand for bioactive secondary metabolites of natural origin is increasing every day. Micropropagation could be a strategy to respond more quickly to market demands, regardless of seasonality. This research aims to evaluate in vitro-grown plants of two hop varieties, namely Columbus and Magnum, as a potential source of bioactive compounds. The extracts were characterized in terms of total phenolic content by a Folin-Ciocalteu assay and antioxidant capacity by DPPH•, ABTS+, and FRAP assays. The bioactive compound profile of the extracts from both varieties was determined by using UPLC-ESI-QqQ-MS/MS. The results confirmed richness in (poly)phenols and other secondary metabolites of the in vitro-grown hop plantlets. Thirty-two compounds belonging to the major families of phytochemicals characteristic of the species were identified, and twenty-six were quantified, mainly flavonoids, including xanthohumol and isoxanthohumol, phenolic acids, as well as α- and β-acids. This study confirms the validity of in vitro-derived hop plantlets as source of bioactive compounds to be used in the nutraceutical, pharmaceutical, and food industries.

First Report on Mycotoxin Contamination of Hops (Humulus lupulus L.)

The presence of mycotoxins and other toxic metabolites in hops (Humulus lupulus L.) was assessed for the first time. In total, 62 hop samples were sampled in craft breweries, and analyzed by a multi-toxin LS-MS/MS method. The study collected samples from craft breweries in all of the Croatian counties and statistically compared the results. Based on previous reports on Alternaria spp. and Fusarium spp. contamination of hops, the study confirmed the contamination of hops with these toxins. Alternaria toxins, particularly tenuazonic acid, were found in all tested samples, while Fusarium toxins, including deoxynivalenol, were present in 98% of samples. However, no Aspergillus or Penicillium metabolites were detected, indicating proper storage conditions. In addition to the Alternaria and Fusarium toxins, abscisic acid, a drought stress indicator in hops, was also detected, as well as several unspecific metabolites. The findings suggest the need for monitoring, risk assessment, and potential regulation of Alternaria and Fusarium toxins in hops to ensure the safety of hop usage in the brewing and pharmaceutical industries. Also, four local wild varieties were tested, with similar results to the commercial varieties for toxin contamination, but the statistically significant regional differences in toxin occurrence highlight the importance and need for targeted monitoring.

Optimization of Antifungal Properties of Hop Cone Carbon Dioxide Extracts Based on Response Surface Methodology

Response surface methodology (RSM) was employed to optimize the process parameters of the supercritical carbon dioxide extraction of hop cones in terms of their antifungal properties against Fusarium culmorum and Aspergillus niger. The effects of temperature (40-50 °C), pressure (200-300 bar), and CO2 consumption (25-75 kgCO2/kg) on the extraction yield, content of α- and β-acids, as well as pathogens' growth inhibition were investigated. Both pressure and CO2 consumption had a significant effect on antifungal properties. It was observed that the best results for antifungal properties were obtained when hop cones were extracted with pure carbon dioxide at the temperature of 50 °C, under the pressure of 300 bar with CO2 consumption at the level of 75 kgCO2/kg of feed for extraction. The highest antifungal properties of hop cone supercritical carbon dioxide extracts were analyzed as 100% for Fusarium culmorum and 68% for Aspergillus niger, calculated as the growth inhibition of tested pathogens. The aim of the study was to determine the optimum values of extraction parameters to achieve the maximum response and enable us to investigate the interaction of these parameters on the antifungal properties of hop cone extracts.

The quest for the perfect loaf of sourdough bread continues: Novel developments for selection of sourdough starter cultures

Sourdough fermentation, one of the oldest unit operations in food production, is currently experiencing a revival in bread production at the household, artisanal, and the industrial level. The expanding use of sourdough fermentation in bread production and the adaptation of fermentation to large scale industrial bread production also necessitate the development of novel starter cultures. Developments in the last years also have expanded the tools that are used to assess the metabolic potential of specific strains, species or genera of the Lactobacillaceae and have identified multiple ecological and metabolic traits as clade-specific. This review aims to provide an overview on the clade-specific metabolic potential of members of the Lactobacillaceae for use in sourdough baking, and the impact of these clade-specific traits on bread quality. Emphasis is placed on carbohydrate metabolism, including the conversion of sucrose and starch to soluble polysaccharides, conversion of amino acids, and the metabolism of organic acids. The current state of knowledge to compose multi-strain starter cultures (synthetic microbial communities) that are suitable for back-slopping will also be discussed. Taken together, the communication outlines the current tools for selection of microbes for use in sourdough baking.

Physicochemical Characteristics, Antioxidant Properties, Aroma Profile, and Sensory Qualities of Value-Added Wheat Breads Fortified with Post-Distillation Solid Wastes of Aromatic Plants

The influence of incorporation of post-distillation solid wastes of the aromatic plants (SWAP), oregano, rosemary, lemon balm, and spearmint into wheat breads at 1% and 2% levels on their physicochemical and sensorial properties, and antioxidant and volatile profiles were investigated. SWAP breads had darker crumbs and crust and greener crumbs compared to the control, but rather similar loaf specific volume and textural attributes (crust puncture test and crumb Texture Profile Analysis). Although the mold growth on bread crumb surface was not inhibited by SWAP presence, LC-DAD-MS revealed a large increase in terpenoids, like carnosic acid (all SWAP), carnosol (rosemary) and carvacrol (oregano), phenolic (rosmarinic and salvianolic) acids and flavonoids in bread with SWAP inclusion, leading to enhanced antioxidant capacity (ABST, DPPH and FRAP assays). The distinct aromatic plant flavors were detected in the fortified breads by trained assessors and confirmed by SPME-GC/MS volatile analysis, showing high levels of terpenoids in SWAP breads, like carvacrol (oregano), caryophyllene (rosemary and lemon balm), and carvone (spearmint), and rendering the 2% fortification unacceptable by consumers. Nevertheless, breads with 1% oregano or rosemary waste had similar control overall acceptability scores, indicating that SWAP can be a promising ingredient for developing antioxidant-enriched wheat breads.

In situ produced exopolysaccharides by Bacillus coagulansIBRC-M 10807 and its effects on properties of whole wheat sourdough

This study aimed to investigate in situ exopolysaccharides (EPSs) production by Bacillus coagulans IBRC-M 10807 under different fermentation conditions to improve the technical-functional properties of whole wheat flour sourdough and obtain high-quality products. For this purpose, the effectiveness of four efficient factors including B. coagulans (8 Log CFU/g), FOS (0%, 2.5%, and 5% based on flour weight), fermentation temperature (30, 35, and 40°C), and fermentation time (12, 18, and 24 h) was investigated on the production of functional sourdough. Our work focused on optimizing probiotic sourdough by investigating probiotic viability, pH, total titratable acidity, antioxidant properties, and EPS measurement. The first optimal formulation for maximized production of the in situ EPSs by the numerical optimization included FOS 0%, B. coagulans IBRC-M 10807 8 Log CFU/g, fermentation temperature of 30°C, and fermentation time of 12 h. In this case, EPSs was 59.28 mg/g and probiotic was 10.99 Log CFU/g. The second optimal formula by considering the highest viability of probiotic together with EPS production was determined as FOS 4.71%, B. coagulans IBRC-M 10807, 8 Log CFU/g, fermentation temperature of 30°C, and fermentation time of 20 h. The predicted amount of the EPSs and probiotic viability via the second formulation were 54.4 mg/g and 11.18 Log CFU/g, respectively. Analyses of optimal sourdough using FTIR, SEM, and DSC revealed that FOS and probiotics significantly reduced the enthalpy of amylopectin retrogradation and delayed it compared to other samples. Therefore, improving the final product's technological capabilities and shelf life can be credited with potential benefits.

Current strategies for the management of valuable compounds from hops waste for a circular economy

World beer production generates large volumes of waste discharged with every brew. Recently, new methods of reducing and reusing hops waste: hot trub (HT), and brewer-spent hops (BSH) are being exploited to improve the circular economy processes. This review outlines the current achievements in the management of hops waste. Following an in-depth review of various scientific publications, current strategies are discussed as a sustainable alternative to food waste exploitation and an inexpensive source of valuable compounds. Moreover, key aspects concerning the nutritional value of hops waste and the potential to enhance the functional properties of food and beverages are highlighted. Due to their nutritional composition, hops residues may be used as prospective sources of added-value co-products or additives for food enrichment, especially for products rich in fat, or as a new source of vegetable protein.

Up-Cycling Grape Pomace through Sourdough Fermentation: Characterization of Phenolic Compounds, Antioxidant Activity, and Anti-Inflammatory Potential

Despite its appealing composition, because it is rich in fibers and polyphenols, grape pomace, the major by-product of the wine industry, is still discarded or used for feed. This study aimed at exploiting grape pomace functional potential through fermentation with lactic acid bacteria (LAB). A systematic approach, including the progressively optimization of the grape pomace substrate, was used, evaluating pomace percentage, pH, and supplementation of nitrogen and carbon sources. When grape pomace was used at 10%, especially without pH correction, LAB cell viability decreased up to 2 log cycles. Hence, the percentage was lowered to 5 or 2.5% and supplementations with carbon and nitrogen sources, which are crucial for LAB metabolism, were considered aiming at obtaining a proper fermentation of the substrate. The optimization of the substrate enabled the comparison of strains performances and allowed the selection of the best performing strain (Lactiplantibacillus plantarum T0A10). A sourdough, containing 5% of grape pomace and fermented with the selected strain, showed high antioxidant activity on DPPH and ABTS radicals and anti-inflammatory potential on Caco2 cells. The anthocyanins profile of the grape pomace sourdough was also characterized, showing qualitative and quantitative differences before and after fermentation. Overall, the grape pomace sourdough showed promising applications as a functional ingredient in bread making.

Identification of colupulone and lupulone as the main contributors to the antibacterial activity of hop extracts using activity-guided fractionation and metabolome analysis

Hop is widely used in beer brewing and as a medicinal product. The present study comprehensively analyzed the main molecular determinants of the antibacterial activity of hop extracts. Minimum inhibitory concentrations (MIC) against Bacillus subtilis between 31.25 and 250 µg/mL were found in the ethanolic extracts of five hop varieties for beer brewing, but not in the tea hop sample. Activity-guided fractionation revealed the highest antibacterial activity for lupulone and adlupulone (MIC 0.98 µg/mL). Metabolome profiling and subsequent multistep statistical analysis detected 33 metabolites out of 1826 features to be associated with the antibacterial activity including humulone, adhumulone, colupulone, lupulone, and adlupulone. Xanthohumol, the three humulone- and three lupulone congeners were quantified in the hop extracts by a validated ultrahigh-performance liquid chromatography-mass spectrometry method. Considering concentrations and MICs, colupulone and lupulone were identified as major contributors to the antibacterial activity of hop extract with the highest antibacterial activity values (concentration/MIC) of 1.59 and 2.56.

Enhancement of agri-food by-products: green extractions of bioactive molecules with fungicidal action against mycotoxigenic fungi and their mycotoxins

Introduction

Today, alternative strategies based on the use of bioactive compounds have been proposed to reduce mycotoxin contamination and limit the use of chemical fungicides.

Methods

In the present work, several by-products collected from the agri-food chain (i.e., red and white grape marc, red grapevine leaves, grape seeds and stalks, pear, apple, green beans, tomato, and spent hops) were subjected to green extraction protocols (i.e., steam distillation, Ultrasound-Assisted, and Naviglio® extraction) to obtain extracts rich in polyphenols and terpenes. Each extract was assessed in vitro for its ability to inhibit the development of the main mycotoxigenic species and related mycotoxins.

Results and Discussion

Aspergillus flavus and A. carbonarius were significantly reduced by pear (from -45 to -47%) and grape marc (from -21 to -51%) extracts, while F. graminearum was shown to be highly influenced by grape stalk, pear, and grape marc extracts (-24% on average). On the contrary, F. verticillioides was inhibited only by pear (-18%) and to a very low and negligible extent by apple (-1%) and green beans (-3%). Regarding the reduction of mycotoxins, the extracts were able to inhibit OTA from 2 to 57%, AFB1 from 5 to 75%, and DON from 14 to 72%. The highest percentages of reduction were obtained against FBs (from 11 to 94%), ZEN (from 17 to 100%), and Alternaria toxins (from 7 to 96%). In conclusion, this work provided promising results for the production of bioactive extracts obtained from agri-food by-products, which could be exploited as potential biofungicides against the development of mycotoxigenic fungi and related mycotoxins.

Beyond brewing: β-acid rich hop extract in the development of a multifunctional polylactic acid-based food packaging

Hops' (Humulus lupulus L.) phytochemicals are well known for their bioactivity. In the present study, the functional properties of hop extract rich in β-acids, as potassium-salts structures (KBA), were investigated to develop a sustainable active food packaging. Polylactic acid (PLA)-based sheets were incorporated with increasing concentrations of hop extract (0.1-5 % w/w in terms of KBA) and characterized through performance and bioactive properties. KBA-added sheets presented decreased crystallinity and affected mechanical and thermal properties, especially with higher KBA amounts. The sheets' surface hydrophobicity gradually decreased by KBA-extract addition, while the water vapor permeability was not affected. A Fickian diffuse behavior and a better fit to application in fatty foods were observed during release tests. UV-blocking and antioxidant properties were improved by KBA incorporation. Furthermore, results from antibacterial assays revealed great susceptibility of Staphylococcus aureus and Listeria monocytogenes towards sheets added with 5 % of KBA. Moreover, the atomic force microscopy (AFM) observations revealed that KBA led to strong effects on the cell membranes of both bacteria, including disruption of membrane integrity and cell death. Therefore, this study is a sign of great prospects of hop β-acids use, as KBA compound, in the production of sustainable active packaging for safe food shelf-life extension.

Conventional and innovative extraction technologies to produce food-grade hop extracts: Influence on bitter acids content and volatile organic compounds profile

Hop extracts represent a natural alternative to synthetic food additives because of their high content of bitter acids and volatile organic compounds (VOCs) with bittering, flavoring, and antimicrobial properties. However, broader uses of hop extracts as natural techno-functional ingredients rely on the identification of sustainable and affordable extraction technologies allowing to diversify the processes and produce extracts characterized by different compositions and, consequently, qualitative properties. Thus, this study is aimed to evaluate and compare the effect of innovative and conventional extraction methods on the bitter acids content and VOCs pattern of food-grade ethanolic hop extracts for food applications. Innovative extractions were carried out by using two ultrasound systems (a laboratory bath [US] and a high-power ultrasound bath [HPUS]), and a high-pressure industrial process (high hydrostatic pressure [HHP]). Conventional extractions (CONV) were performed under dynamic maceration at 25 and 60°C; for ultrasound and conventional methods, the effect of the extraction time was also investigated. Among the extracts, the highest and lowest content of bitter acids was found in CONV 60°C extracts, and HHP and CONV 25°C extracts, respectively. Of the 34 VOCs identified in dry hops, ∼24 compounds were found in US, HPUS and CONV extracts, while only 18 were found in HHP. CONV extractions showed higher selectivity for sesquiterpenes, while US and HPUS showed higher selectivity for esters and monoterpenes. Hierarchical cluster analysis (HCA) and partial least squares-discriminant analysis (PLS-DA) allowed classifying hop extracts based on the extraction methods and also allowed highlighting the technological conditions to produce hop extracts with specific techno-functional and flavoring properties. PRACTICAL APPLICATION: The study showed that different extraction methods can lead to hop products with varying sensory and functional properties. By selecting the right extraction method, companies can produce hop extracts with specific compositions that meet their needs for clean label and sustainable food products, as well as new edible packaging or coatings.

Antifungal Mechanisms and Application of Lactic Acid Bacteria in Bakery Products: A Review

Bakery products are nutritious, but they are susceptible to fungal contamination, which leads to a decline in quality and safety. Chemical preservatives are often used to extend the shelf-life of bakery products, but long-term consumption of these preservatives may increase the risk of chronic diseases. Consumers increasingly demand food with fewer chemical preservatives. The application of lactic acid bacteria (LAB) as a novel biological preservative not only prolongs the shelf-life of bakery products but also improves the baking properties of bakery products. This review summarizes different types and action mechanisms of antifungal compounds produced by LAB, factors affecting the production of antifungal compounds, and the effects of antifungal LAB on bakery products, providing a reference for future applications of antifungal LAB in bakery products.

Antioxidants in Hops: Bioavailability, Health Effects and Perspectives for New Products

Hop plant (Humulus lupulus L.) has been used by humans for ages, presumably first as a herbal remedy, then in the manufacturing of different products, from which beer is the most largely consumed. Female hops cones have different useful chemical compounds, an important class being antioxidants, mainly polyphenols. This narrative review describes the main antioxidants in hops, their bioavailability and biological effects, and the results obtained by now in the primary and secondary prevention of several non-communicable diseases, such as the metabolic syndrome related diseases and oncology. This article presents in vitro and in vivo data in order to better understand what was accomplished in terms of knowledge and practice, and what needs to be clarified by additional studies, mainly regarding xantohumol and its derivates, as well as regarding the bitter acids of hops. The multiple protective effects found by different studies are hindered up to now by the low bioavailability of some of the main antioxidants in hops. However, there are new promising products with important health effects and perspectives of use as food supplements, in a market where consumers increasingly search for products originating directly from plants.

Modulation of Adenosine Receptors by Hops and Xanthohumol in Cell Cultures

Adenosine receptors (ARs) have been involved in neurodegenerative diseases such as Alzheimer disease, where oxidative stress contributes to neurodegeneration and cell death. Therefore, there is increasing interest in developing antioxidative strategies to avoid or reduce neurodegeneration. We have previously described that different beer extracts modulate ARs and protect glioma and neuroblastoma cells from oxidative stress. The present work aimed to analyze the possible protective effect of hops (Humulus lupulus L.), a major component of beer, and xanthohumol on cell death elicited by oxidative stress and their modulation of ARs in rat C6 glioma and human SH-SY5Y neuroblastoma cells. Different extraction methods were employed in two hops varieties (Nugget and Columbus). Cell viability was determined by the XTT method in cells exposed to these hops extracts and xanthohumol. ARs were analyzed by radioligand binding and real-time PCR assays. Hops extract reverted the cell death observed under oxidative stress and modulated adenosine A₁ and A₂ receptors in both cell types. Xanthohumol was unable to revert the effect of oxidative stress in cell viability but it also modulated ARs similarly to hops. Therefore, healthy effects of beer described previously could be due, at least in part, to their content of hops and the modulation of ARs.

Hop Polyphenols in Relation to Verticillium Wilt Resistance and Their Antifungal Activity

(1) Background: Verticillium wilt (VW) of hop is a devastating disease caused by the soil-borne fungi Verticillium nonalfalfae and Verticillium dahliae. As suggested by quantitative trait locus (QTL) mapping and RNA-Seq analyses, the underlying molecular mechanisms of resistance in hop are complex, consisting of preformed and induced defense responses, including the synthesis of various phenolic compounds. (2) Methods: We determined the total polyphenolic content at two phenological stages in roots and stems of 14 hop varieties differing in VW resistance, examined the changes in the total polyphenols of VW resistant variety Wye Target (WT) and susceptible Celeia (CE) on infection with V. nonalfalfae, and assessed the antifungal activity of six commercial phenolic compounds and total polyphenolic extracts from roots and stems of VW resistant WT and susceptible CE on the growth of two different V. nonalfalfae hop pathotypes. (3) Results: Generally, total polyphenols were higher in roots than stems and increased with maturation of the hop. Before flowering, the majority of VW resistant varieties had a significantly higher content of total polyphenols in stems than susceptible varieties. At the symptomatic stage of VW disease, total polyphenols decreased in VW resistant WT and susceptible CE plants in both roots and stems. The antifungal activity of total polyphenolic extracts against V. nonalfalfae was higher in hop extracts from stems than those from roots. Among the tested phenolic compounds, only p-coumaric acid and tyrosol markedly restricted fungal growth. (4) Conclusions: Although the correlation between VW resistance and total polyphenols content is not straightforward, higher levels of total polyphenols in the stems of the majority of VW resistant hop varieties at early phenological stages probably contribute to fast and efficient activation of signaling pathways, leading to successful defense against V. nonalfalfae infection.

Humulus lupulus L. as a Natural Source of Functional Biomolecules

Hops (Humulus lupulus L.) are used traditionally in the brewing industry to confer bitterness, aroma, and flavor to beer. However, in recent years, it has been reported that female inflorescences contain a huge variety of bioactive compounds. Due to the growing interest of the consumers by natural ingredients, intense research has been carried out in the last years to find new sources of functional molecules. This review collects the works about the bioactive potential of hops with applications in the food, pharmaceutical, or cosmetic industries. Moreover, an overview of the main extraction technologies to recover biomolecules from hops is shown. Bioactivities of hop extracts such as antibacterial, antifungal, cardioprotective, antioxidant, anti-inflammatory, anticarcinogenic, and antiviral are also summarized. It can be concluded that hops present a high potential of bioactive ingredients with high quality that can be used as preservative agents in fresh foods, extending their shelf life, and they can be incorporated in cosmetic formulation for skincare as well.

Brans from hull-less barley, emmer and pigmented wheat varieties: From by-products to bread nutritional improvers using selected lactic acid bacteria and xylanase

Aiming at meeting the recommendations of the World Health Organization regarding the total fiber daily intake, an integrate biotechnological approach, combining xylanase treatment and lactic acid bacteria fermentation of milling by-products from pigmented wheat varieties, hull-less barley and emmer was proposed. The effects on the biochemical and nutritional features were investigated. Enhanced radical scavenging activity, increased concentrations of free amino acids (up to three times) and peptides and optimal in vitro protein digestibility (up to ca. 87%) value as well as relevant phytic acid degradation were achieved during bran fermentation. The main nutritional features of each matrix were enhanced and distinguished. Fortified breads were characterized by a concentration in total dietary fibers and protein of ca. 7 and 13% of dry matter, respectively. Compared to wheat bread the addition of pre-fermented brans caused a significant increase in protein digestibility (up to 79%), and a relevant decrease of the predicted glycemic index (ca. 8%) of the fortified bread. According to the results, this study demonstrates the potential of xylanase treatment and lactic acid bacteria fermentation to be used as suitable strategy to include bran in breadmaking, meeting both nutritional and sensory requests of modern consumers.

Comparison of bacterial communities in gliadin-degraded sourdough (Khamir) sample and non-degraded sample

The study was undertaken to investigate the comparison lying between bacterial communities in autochthonous gliadin-degraded sourdough sample (D13) and non-degraded sample (D50). Degree of gliadin degradation in various samples was determined by Fourier transform infrared spectroscopy and represented samples were selected for 16 S rDNA sequence analysis by Illumina Miseq platform. It was observed, that Proteobacteria (50.65%) and Actinobacteria (6.70%) phyla were more abundant as compared with Firmicutes (42.53%) in D13, however, Firmicutes (83.44) were more abundant, comparatively, in D50 than Proteobacteria (14.97%). Lower taxonomic levels surfaced its more prominent effects. It had been also observed that Lactobacillus genera was the core genera (50.37%) followed by Weissella (27.15%) and Psychrobacter (21.53%) in D50 and D13, respectively. Shannon and Simpson indices indicated that degraded sample had more bacterial diversity and richness compared with non-degraded sample.

Maize Milling By-Products: From Food Wastes to Functional Ingredients Through Lactic Acid Bacteria Fermentation

Although recognized as important sources of functional compounds, milling by-products are often removed from the cereal kernel prior milling process. Indeed, the high presence of fiber in bran and the co-presence of lipids and lipase in germ are often considered as downsides for breadmaking. In this work, Lactobacillus plantarum T6B10 and Weissella confusa BAN8 were used as selected starters to ferment maize milling by-products mixtures made with heat-treated or raw germ and bran. The effects on the biochemical and nutritional features as well as the stability of the milling by-products were investigated. Lactic acid bacteria metabolisms improved the free amino acids and peptides concentrations and the antioxidant activity and caused a relevant phytic acid degradation. Moreover, fermentation allowed a marked decrease of the lipase activity, stabilizing the matrix by preventing oxidative processes. The use of fermented by-products as ingredients improved the nutritional, textural and sensory properties of wheat bread. Fortified breads (containing 25% of fermented by-products) were characterized by a concentration in dietary fiber and proteins of ca. 11 and 13% of dry matter, respectively. Compared to the use of the unfermented ones, the addition of pre-fermented by-products to bread caused a significant increase in protein digestibility (up to 60%), and a relevant decrease of the starch hydrolysis index (ca. 13%). According to the results, this study demonstrates the potential of fermentation to convert maize bran and germ, commonly considered food wastes, into nutritive improvers, meeting nutritional and sensory requests of modern consumers.

Exploiting synergies of sourdough and antifungal organic acids to delay fungal spoilage of bread

Fungal spoilage of bread remains an unsolved issue in bread making. This work aims to identify alternative strategies to conventional preservatives in order to prevent or delay fungal spoilage of bread. The minimum inhibitory concentration (MIC) of bacterial metabolites and chemical preservatives was evaluated in vitro, and compared to their in situ activity in baking trials. Calcium propionate, sorbic acid, 3-phenyllactic acid, ricinoleic acid, and acetic acid were tested both individually and in combination at their MIC values against Aspergillus niger and Penicillium roqueforti. The combination of acetic acid with propionate and sorbate displayed additive effects against the two fungi. For these reasons, we introduced sourdough fermentation with specific strains of lactobacilli, using wheat or flaxseed, in order to generate acetate in bread. A combination of Lactobacillus hammesii and propionate reduced propionate concentration required for shelf life extension of wheat bread 7-fold. Flaxseed sourdough bread fermented with L. hammesii, excluding any preservative, showed a shelf life 2 days longer than the control bread. The organic acid quantification indicated a higher production of acetic acid (33.8 ± 4.4 mM) when compared to other sourdough breads. Addition of 4% of sucrose to sourdough fermentation with L. brevis increased the mould free shelf-life of bread challenged with A. niger by 6 days. The combination of L. hammesii sourdough and the addition of ricinoleic acid (0.15% or 0.08%) prolonged the mould free shelf-life by 7-8 days for breads produced with wheat sourdoughs. In conclusion, the in vitro MIC of bacterial metabolites and preservatives matched the in situ antifungal effect. Of the different bacterial metabolites evaluated, acetic acid had the most prominent and consistent antifungal activity. The use of sourdough fermentation with selected strains able to produce acetic acid allowed reducing the use of chemical preservatives.

Nuevos xenófitos de La Palma (Islas Canarias, España), con énfasis en las especies naturalizadas y (potencialmente) invasoras. Parte 2

Varios meses de trabajos de campo en La Palma (Islas Canarias occidentales) han posibilitado el descubrimiento de nuevas plantas vasculares no nativas. Abutilon theophrasti, Agrostis xfouilladeana, Alternanthera brasiliana, Bupleurum salicifolium subsp. salicifolium, Callisia fragrans, Emilia coccinea, Hyparrhenia sinaica, Ipomoea purpurea, Jasminum polyanthum, Macfadyena unguis-cati, Malvastrum coromandelianum subsp. coromandelianum, Misopates calycinum, Nephrolepis cordifolia, Opuntia microdasys, Passiflora subpeltata, Plantago lanceolata, Polygonum aviculare subsp. rurivagum, Pseudogynoxys chenopodioides, Psidium littorale, Robinia pseudoacacia, Rosa micrantha, Rumex bucephalophorus subsp. gallicus, Sorghum bicolor subsp. verticilliflorum, Sphagneticola trilobata, Syzygium jambos, Thunbergia alata y Youngia japonica subsp. japonica son xenófitos naturalizados o (potencialmente) invasores, se citan por primera vez para las Islas Canarias o para La Palma. Se dan a conocer por primera vez 14 t·axones adicionales, probablemente casuales, de las Islas Canarias y 15 taxones de la isla de La Palma.