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•Xanthohumol has several pharmacological properties of interest for human health.•Female inflorescences of Humulus lupulus (Hops) are the natural source of xanthohumol.•Emerging ...technologies have been investigated to increase xanthohumol extraction yield.•Hot trub and spent hops, by-products from beer brewing, can be sources of xanthohumol.
Xanthohumol, a chalcone unique to hops, has attracted attention from researchers due to its several pharmacological effects on humans. In industry, hops are almost exclusively used in beer production, generating tons of solid waste – hot trub from the boiling step and spent hops from the dry hopping – rich in biocompounds, among them xanthohumol, that could be recovered and used for several nutritional purposes. The literature is extensive on extraction processes of xanthohumol directly from hops, but only a few studies present its recovery from brewery solid waste. We focus on presenting the xanthohumol characteristics and benefits for human consumption, and discuss the main extraction techniques, their advantages and limitations, to prospect strategies to recover this high-value compound from brewing solid waste. Recent extraction processes represent promising approaches to overcome the limitations of conventional methods, but further studies are still needed to understand xanthohumol extraction and purification and induce industrial upscaling.
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•Enriched bitter acids extract from a Brazilian hop variety was successfully produced.•Drying temperature greatly affects hop color and total essential oil content.•Lupulin gland ...protected bitter acids and xanthohumol from oxidation during drying.•Drying up to 70 °C does not influence Supercritical CO2 extraction yields.
Hop cultivation has been increasing in the past decade in Brazil, demanding a better understanding of how the processing influences the national hop varieties. Despite the hop process being well-established in the producer countries, there is still room for optimization to reduce energy consumption for a more sustainable process. This study’s main purpose was to understand the influence of drying and supercritical CO2 extraction on the quality of hop extracts. The hop quality during drying was evaluated regarding color, bitter acids, xanthohumol, total essential oil content, and volatile profile. Supercritical CO2 extraction yields, and bitter acid recovery were assessed by HPLC in a range of different temperatures (40 or 60 °C) and pressure (15, 20, 25, or 30 MPa) conditions. Hop processing was optimized to produce a greater extract quality from a Brazilian hop variety, saving energy and solvent consumption, and consequently, reducing the process footprint. Furthermore, this study established supercritical CO2 extraction conditions for Brazilian hop extract production, offering the national beer industry an alternative to overpriced products.
Hops are a major component of beer that is added during brewing. In addition to its wide range of bioactivity, it exhibits neuroactive properties as a sedative and sleeping aid. The compounds ...responsible for this activity are yet to be revealed and understood in terms of their pharmacological properties. Here we evaluated the potential of several hops flavonoids in modulating the GABAergic activity and assessed their selectivity to GABAA receptors subtypes. GABA-potentiating effects were measured using 3Hethynylbicycloorthobenzoate (EBOB) radioligand binding assay in native and recombinant α1β3γ2, α2β3γ2 and α6β3δ receptors expressed in HEK293 cells. Flumazenil sensitivity of GABA-potentiating effects and 3HRo 15-4513 binding assay were used to examine the flavonoids binding to benzodiazepine site. The prenylflavonoids xanthohumol (XN), isoxanthohumol (IXN) and 8-prenylnaringenin (8PN) potentiated GABA-induced displacement of 3HEBOB binding in a concentration-dependent manner. The IC50 for this potentiation in native GABAA receptors were 29.7 µM, 11.6 µM, 7.3 µM, respectively. In recombinant receptors, the sensitivity to prenylflavonoid potentiation of GABA-induced displacement of 3HEBOB binding followed the order α6β3δ > α2β3γ2 > α1β3γ2 with the strongest inhibition observed by 8PN in α6β3δ (IC50 = 3.6 μM). Flumazenil had no significant effect on the prenylflavonoid-induced displacement of 3HEBOB binding and 3HRo 15-4513 displacement from native GABAA receptors was only detected at high micromolar concentrations (100 µM). We identified potent prenylflavonoids in hops that positively modulate GABA-induced responses in native and αβγ/δ recombinant GABAA receptors at low micromolar concentrations. These GABAergic modulatory effects were not mediated via the high-affinity benzodiazepine binding site.
What is new on the hop extraction? Sanz, Vanesa; Torres, María Dolores; López Vilariño, José M. ...
Trends in Food Science & Technology,
11/2019, Volume:
93
Journal Article
Peer reviewed
Hops are mostly processed for the extraction of compounds conferring aroma and bitterness to beer. A more controllable addition of these properties can be achieved when solvent hop extracts are ...produced and added in the desired brewing stage.
This review presents a survey on the research and patents on emerging extraction technologies and the importance of the solvent and operational conditions on the composition of hop extracts, destined for the brewing industry, but also for the production of novel ingredients with potential for nutraceuticals.
For the preparation of extracts, the efficiency of conventional solvents has been progressively improved by the assistance with intensified technologies and particularly by the use of greener solvents, a trend where this industry has been pioneer. The design of multistage multiproduct processes for the integral utilization of hops following a biorefinery approach is also addressed.
•Hops components are extracted to provide aroma and bitterness to beer.•Hop extracts are more efficient to provide organoleptic properties.•Green extraction technologies can provide extracts enriched in bioactives.•Integral valorization of hops following a biorefinery approach is recommended.
The harvesting of hops (Humulus lupulus L.) generates large amounts of nutrient-rich leaves that can be used in composting mixtures to add value to other organic resources on the farm. In this study, ...hop leaves were mixed with cow manure and wheat straw in several combinations with the aim of establishing guidelines on how farmers can manage the raw materials and better use these valuable organic resources. The composting process was monitored and the quality of the composts evaluated in relation to the effects on lettuce (Lactuca sativa L.) grown in pots over two consecutive cycles. The mixture of hop leaves with cow manure produced a stable compost after nine months of composting which may be used in horticultural crops, irrespective of the proportion of raw materials, due to their low and similar C/N ratios. However, when using mixtures of leaves and straw in proportions of less than 2:1, the composts did not mature properly, showing high C/N ratios. Their application to the soil led to a strong reduction in plant tissue N concentrations, due to biological N immobilization, which significantly reduced lettuce dry matter yield. Thus, to reduce composting time and increase the quality of the compost, the ratio leaves/straw should be as high as possible, at least 2:1. Alternatively, either the composting process should take longer, or the poorly-matured compost be applied far in advance of sowing a crop so that complementary biological processes can take place in the soil, as recorded in the second cycle of lettuce. Ash from hop stems did not benefit the composting process and proved itself not to be worth using in mixtures.
•Hop leaves accelerated the decomposition rate and increased the quality of straw-based composts.•Hop leaves and farmyard manure produced stable composts irrespective of the proportion of raw materials.•Ash from hop stems did not add anything relevant to the composting process of hop leaves and other waste.•Poorly-matured compost should be applied far in advance of sowing a crop.
Hop powdery mildew, caused by Podosphaera macularis, may be initiated by sexual or asexual spores of the pathogen, but only asexual reproduction has been reported in the Pacific Northwest United ...States. In this region, overwintering is via bud perennation, leading to "flag shoots" the following season. We expanded on previous research and analyzed 766 location-years of flag shoot data from Oregon hop yards collected from 2014 to 2020, examining potential risk factors of yard age, cultivar susceptibility to powdery mildew, pruning method (mechanical means or not), and pruning thoroughness. Bayesian logistic regression models were fitted to estimate the probability of flag shoot presence or absence. We found little evidence to support yard age as a significant risk factor for flag shoot presence, as the 95% credible interval for the parameter associated with yard age was consistently centered around 0 in each of our models. However, cultivar susceptibility to powdery mildew, spring pruning method, and spring pruning thoroughness were associated with increases in the probability of observing a flag shoot. Although yard age was not an important risk factor, there was an interrelationship between yard age, pruning method, and pruning thoroughness that suggests second-year yards may indirectly be at an elevated risk for flag shoot development because these yards are less often pruned using mechanical methods. Our research further identifies yards that are most at risk for overwintering of P. macularis and reinforces the importance of thorough pruning in yards with an elevated risk for possessing a flag shoot. Formula: see text The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2023.
ABSTRACT Hop (Humulus lupulus L.) is one of the most important raw materials of beer production. Despite being the third-largest producer and consumer of beer worldwide, Brazil imports almost all ...hops for production. Nitrogen is an essential macronutrient for hop development and its behavior under different doses is still unknown for Brazilian conditions. Our goal was to evaluate the dry matter and essential oil yields of the Chinook hop fertilized with five N rates during three harvests. Leaves, branches, and cones were sampled to determine their dry matter production, and cones were also analyzed for essential oil contents, extracted by hydrodistillation. Cone number per plant, cone, branch, and leaf dry matter yields, as well as total essential oil yield per plant, increased linearly as nitrogen rates were raised. The production of DM of cones obtained ranged between 245.8 (N:0) and 386.7 kg ha-1 (N:250 kg N ha-1). Yield differences were also noted between harvest years due to weather conditions. Therefore, we can conclude that increasing N rates and climatic conditions affect N contents in hop leaves, as well as hops overall and oil yields, due to the higher cone dry matter. However, essential oil contents in cone dry matter did not change.
Novel smart cotton diagnostic assay was developed toward onsite sensing of sweat pH variations for possible medical applications such as drug test and healthcare purposes. Humulus lupulus L. extract ...was obtained according to previously reported procedure. As reported by high‐performance liquid chromatography (HPLC), the extract demonstrated the presence of hop acids, prenylchalcones, and prenylflavanones, which is responsible for the colorimetric changes. The extract was applied to cellulose fibers employing potassium aluminum sulfate as mordant. This was observed by the formation of mordant/xanthohumol nanoparticles onto cotton surface. The absorption spectra and CIE (Commission Internationale de l'Eclairage) Lab screening of the prepared cotton assay showed colorimetric changes in association with hypsochromic shift from 600 nm to 433 nm upon exposure to sweat simulant fluid (pH < 7). The biochromic activity of the xanthohumol‐finished cotton depends mainly on the halochromic performance of the xanthohumol chromophore to show a colorimetric switch from yellow to white owing to intramolecular charge transfer in the xanthohumol molecule. No substantial defects were detected in gas‐permeability and stiffness of the treated fabrics. Satisfactory fastness was approved for the xanthohumol‐dyed diagnostic cotton assay.
Environmentally friendly cotton swab was prepared for onsite sweat monitoring. Humulus lupulus L. extracted from common hop was immobilized into cotton assay. Color shift from yellow to white was detected due to sweat biochemical changes. Sweat monitoring showed hypsochromic shift was detected from 600 to 433 nm. No substantial defects were detected in comfortability of treated fabrics.
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