Hop plants comprise a variety of natural compounds greatly differing in their structure and properties. A wide range of methods have been developed for their isolation and chemical analysis, as well ...as for determining their antioxidative, antimicrobial, and antigenotoxic potentials. This contribution provides an overview of extraction and fractionation techniques of the most important hop compounds known for their health-promoting features. Although hops remain the principal ingredient for providing the taste, stability, and antimicrobial protection of beer, they have found applications in the pharmaceutical and other food industries as well. This review focuses on numerous health-promoting effects of hops raging from antioxidative, sedative, and anti-inflammatory potentials, over anticarcinogenic features to estrogenic activity. Therefore, hops should be exploited for the prevention and even healing of several prevalent diseases like cardiovascular disorders and various cancer types. New ideas for future studies on hops are finally presented: computational investigations of chemical reactivities of hop compounds, nanoencapsulation, and synergistic effects leading to a higher bioavailability of biologically active substances as well as the application of waste hop biomass from breweries for the production of high-added-value products in accordance with the biorefinery concept.
Hop cones (Humulus lupulus L.), or more specifically the lupulin glands, hold the reason for the specific, pleasant aroma of hops - its essential oil. The hops themselves, or the extracted oil, are ...used almost exclusively in beer production. The essential oil is an indispensable part of beer and is responsible for its characteristic aroma. However, hop essential oil (HEO) also has a broad range of positive effects on human health and is a potential natural pesticide that has no harmful impacts on humans. This review summarizes basic information about HEO, including its chemical composition and methods for extraction and analysis, while also providing a comprehensive overview of the contribution to beer aroma, health, and insecticide applications for this versatile essential oil.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
A need exists for a reliable method to determine the geographical and botanical origin of hops. For this study, three sets of samples were collected: the first set comprised 5 German samples; the ...second set comprised samples of hops from 10 of the world’s major hop-growing regions; and the third comprised the 4 main Slovenian regions. The samples were analyzed using isotope ratio mass spectrometry (IRMS) to obtain δ13C, δ15N, and δ34S values. The δ15N (2.2 ‰ to 8.4 ‰) and δ34S (0.7 ‰ to 12.3 ‰) values were the most discriminating parameters for classifying hop according to geographical origin. ANOVA showed distinct groupings for 8 out of the 10 hop-growing regions. Although it was not possible to distinguish the geographical origin of hops based on δ13C (−28.9 ‰ to −24.7 ‰), in the case of botanical origin, δ13C values proved to be the most discriminative albeit with limited success.
Hops' unique composition of essential oil components and bitter resins are crucial for beer aroma, which is important to consumers' acceptance of beer. In this experiment the same wort was divided ...into four portions and each was hopped differently. To determine the dynamics of isomerization rates the concentrations of alpha- and iso-alpha-acids were continuously measured. Measurements of hop essential oil components were performed during each process to understand the dynamics of the transition into beer. The maximum isomerization yield of alpha-acids (18.1%) was achieved after 100 min. Longer boiling increased the reduction of iso-alpha-acids, as well as essential oil components. Dry hopping also affected not only on beer aroma but also on beer bitterness.
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•Pumpkin seeds of Gleisdorf and Rustikal, were roasted at different temperatures.•All pumpkin seed samples were chemically extracted to gain oil.•Amount of tocopherols and phenols ...decreased with increasing roasting temperature.•The antioxidant capacity of pumpkin seed oil increased with roasting up to 110 °C.
To achieve the aroma and colour typical of pumpkin seed oil, production includes a roasting step, in which pressed pumpkin seeds are exposed to temperatures of 110 °C and above for up to 60 min. Our purpose was to investigate the effect of roasting temperature on pumpkin seed oil tocopherols and phenolics as important compounds for its nutritional value. In this study, pumpkin seeds of two varieties were roasted at temperatures from 90 to 200 °C, with one sample left unroasted for comparison purposes. Concentrations of α- and γ-tocopherol and phenolic compounds, as well as antiradical activity, were determined. Among the polyphenols, vanillic, caffeic, transcinnamic and p-coumaric acid were detected. The highest observed concentrations of these polyphenolic acids were 3.08, 0.42, 2.48 and 1.91 mg/kg, respectively. As roasting temperatures increased, polyphenol concentrations decreased. The least significant changes were observed in α- and γ-tocopherols, with concentrations ranging from 51 to 113 mg/kg and 356 to 646 mg/kg, respectively. Antiradical activity was determined spectrophotometrically via 2,2-diphenyl-1-picrylhydrazyl (DPPH) testing. The antiradical effect values ranged from 31.4 to 70.6% and 19.3 to 47.7% for Gleisdorf and Rustikal samples, respectively. Several chemical parameters (acid, saponification, peroxide and iodine values) were also examined.
Hemp (Cannabis sativa L.) cannabinoids and terpenoids have therapeutic effects on human and animal health. Cannabis plants can often have a relatively high heterogeneity, which leads to different ...phenotypes that have different chemical profiles despite being from the same variety. Little information exists about cannabinoid and terpenoid profiles in different hemp phenotypes within the same variety. For this study, 11 phenotypes from three different varieties (“Carmagnola” selected (CS), “Tiborszallasi” (TS), and “Finola” selection (FS)) were analyzed. The components of essential oil (29) were analyzed using gas chromatography with flame ionization detection (GC/FID), and 10 different cannabinoids of each phenotype were determined using high-performance liquid chromatography (HPLC). Principal component analysis (PCA) and analysis of variance (ANOVA) showed that according to the components of essential oil, FS and TS plants were more uniform than CS plants, where there were great differences between CI and CII phenotypes. The content of cannabinoid CBD-A was the highest in all four FS phenotypes. By comparing cannabinoid profiles, FS was clearly separated from TS and CS, while these two varieties were not clearly distinguishable. Phenotypes TV and CI had the highest total content of Δ-9-THC, while all phenotypes of FS had the highest total content of CBD. The highest total content of CBG was determined in phenotype CI. Obtained results are useful for the development of new supplementary ingredients, for different pharmacy treatments, and for further breeding purposes.
In 2019, we conducted a field experiment to test the effects of three different granular fertilizers on the salicylic acid and total phenolic contents in five different sport turfgrass mixtures under ...natural conditions. It was one of the first experiments assessing the natural resistance of sport turfgrass in Europe. In five terms, before and after fertilizers applications, we randomly collected turfgrass samples within each plot for chemical analyses. The turfgrass mixtures did not affect the average contents of salicylic acid and total polyphenols. The average contents of both compounds were influenced by the date of evaluation and fertilization scheme. The average content of salicylic acid was significantly the lowest under fertilization scheme C. The highest level of salicylic acid was detected on 18th June under scheme A and the lowest on 28th May, where the salicylic acid content ranged from 0.01 ± 0.00 mg.g
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under scheme A to 0.017 ± 0.00 mg.g
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under scheme B and 0.006±0.00 mg.g
−1
under scheme C. The content of total polyphenols was higher under fertilization schemes B and C. We conclude that the method of fertilization exerts a certain effect on the salicylic acid and total polyphenol contents in turfgrass mixtures, which also depends on environmental factors.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The production of lager beer includes successive repitchings of a single
starter culture. During the beer production process, the yeast is exposed to several stress factors which could affect the ...fermentation performance. An incomplete fermentation represents a waste of fermentable extract and leads to a beer with higher carbohydrate levels, which could result in a beer with an atypical flavour profile. The aim of the present study is to determine the impact of successive exploitation of a single
starter culture on the wort saccharide uptake dynamics.
The fermentation was monitored during the production of twelve batches of beer, where the starter yeast culture was reused twelve times without any further treatment. The following beer production steps were monitored: wort production, yeast starter culture propagation, primary fermentation, secondary fermentation and the final product. The work was conducted on an industrial scale employing standard process conditions.
Monitoring of the starter culture viability during successive fermentations indicated no reduction in the viability and vitality of the yeast culture. Monitoring of the fermentable wort saccharide concentrations (glucose, fructose, disaccharides and trisaccharides) revealed a correlation between an improvement in saccharide utilisation and starter culture age. Saccharide uptake efficacy proportionally matched the repitching frequency. Successive exploitation of
starter culture has a positive impact on the dynamics of saccharide utilisation from classical hopped wort and the young beer. Furthermore, the final lager beer contains no residues of fermentable saccharides that could affect the overall quality and flavour profile.
Results showed the impact of twelve successive wort fermentations on the dynamics of saccharides uptake that gives brewers important information. The added value of the experiment is all the work done on the industrial scale, with control of all processes and usage of exactly the same raw materials. This study contains usable technological data on the behaviour of saccharides during brewing on the industrial scale, which is not yet found in the literature.
•Multi-elemental fingerprinting can be used for determination of geographical origin of hops.•The most significant parameters in the discrimination were Si, Ti, Fe and Sr.•Effective differentiation ...between European and non-European was achieved.
For brewers, it is important to know the geographic origins of the hop plants (Humulus lupulus L.) used in their brewing processes since the contents and compositions of the bitter resins and essential oils in them depend on the environmental conditions during their growth. In this study, the multi-elemental profiles of hop plants from each of the world’s main growing regions were determined by non-destructive energy dispersive X-ray fluorescence spectrometry (EDXRF). Understanding the multi-element profiles of the plants could be a useful tool in determining the geographic origins of produced hop plants.
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