Frontier Research in Hop

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Food Science and Technology".

Deadline for manuscript submissions: closed (15 March 2022) | Viewed by 15394

Special Issue Editors


E-Mail Website
Guest Editor
Department of Food and Drug, University of Parma, 43124 Parma, Italy
Interests: micropropagation; flower and fruit biology; frost damage; systematic pomology; evaluation of fruit quality; varietal selection
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Department of Food and Drug, University of Parma, 43124 Parma, Italy
Interests: plant biotechnology; genetic diversity; molecular markers; food science; agricultural biotechnology; agronomy; plant production

E-Mail Website
Guest Editor
Department of Food and Drug, University of Parma, 43124 Parma, Italy
Interests: plant biotechnology; genetic diversity; molecular markers; chemical characterization; food science; agricultural biotechnology; plant production
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Humulus lupulus L., also known as hops, is a dioecious perennial climbing species, and female plants are of economic interest thanks to their flowers, which are rich in secondary metabolites. Hops is acknowledged to provide an aroma and bitterness to the creations of the brewing industry, but also for the presence, in hop strobiles, of bioactive compounds of pharmacological interest. Hops has traditionally been grown in temperate zones of the globe, including different areas of Europe, the United States, China, Australia, and New Zealand. However, in the last few decades, hop cultivation has spread to non-traditional growing areas. Moreover, we perceive a need for innovation in this ancient crop with regard to both cultivation and the use of hops and breweries by-products.

No less interesting, from an environmental and economic point of view, are topics related to phytochemical studies that aim to explore the composition of hops cones and other parts of the hops plant (leaves, stems, and rhizomes) in order to identify bioactive molecules of health-related value.

This Special Issue represents an opportunity for the scientific community to present recent research on hops biodiversity characterization and innovative extraction methods for determining the bioactive compounds in different hops organs.

In addition, we welcome contributions on yield improvement, hops resistances to biotic and abiotic stress, precision agriculture, new systems for hops cultivation, and hops quality (in terms of resin and oil contents and aroma). Innovations in the use of hops by-products in view of “waste to value” and the circular economy will be very important to this Special Issue.

Prof. Dr. Tommaso Ganino
Prof. Dr. Andrea Fabbri
Dr. Margherita Rodolfi
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • hops
  • hops biodiversity
  • hops breeding
  • functional genomics
  • agronomic traits
  • yield improvement
  • biotic resistance
  • abiotic resistance
  • cone quality
  • hops bioactive compounds

Published Papers (6 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

13 pages, 1432 KiB  
Article
Assessment of the Genetic and Phytochemical Variability of Italian Wild Hop: A Route to Biodiversity Preservation
by Margherita Rodolfi, Matteo Marieschi, Benedetta Chiancone and Tommaso Ganino
Appl. Sci. 2022, 12(11), 5751; https://doi.org/10.3390/app12115751 - 06 Jun 2022
Cited by 2 | Viewed by 1526
Abstract
Background: Northern Italy has an enormous heritage of hop biodiversity that need to be exploited and studied. The preservation and valorization through the characterization of the existent biodiversity is a primary goal of the European Green Deal 2023–2030. The aim of this study [...] Read more.
Background: Northern Italy has an enormous heritage of hop biodiversity that need to be exploited and studied. The preservation and valorization through the characterization of the existent biodiversity is a primary goal of the European Green Deal 2023–2030. The aim of this study was to acquire information on the biodiversity of Italian wild hops. Methods: Genetic characterization of sixty accessions was done resorting to Single Sequence Repeated (SSR) markers. Phytochemical characterization of wild hops was achieved using: (i) high-performance liquid chromatography with ultraviolet detection for bitter acids quantification, (ii) steam distillation for essential oils quantification and (iii) Gas Chromatography-Mass Spectrometry for the determination of the aromatic profile. Results: The eight SSR primers showed high Polymorphic Information Content (PIC), especially HlGA23. α-Acids reached values between 0 and 4.125. The essential oils analysis highlighted variability within the studied population, with some accessions characterized by important spicy fraction, and others by fruity and floral notes. Conclusions: The present study allowed the characterization of Italian wild hops and demonstrated an interesting biodiversity. Part of this biodiversity have been shown to be potentially suitable for use in brewing. Moreover, several genotypes could be used in breeding programs to obtain new more sustainable varieties. Full article
(This article belongs to the Special Issue Frontier Research in Hop)
Show Figures

Figure 1

15 pages, 3059 KiB  
Article
On-Farm Composting of Hop Plant Green Waste—Chemical and Biological Value of Compost
by Lucija Luskar, Julija Polanšek, Aleš Hladnik and Barbara Čeh
Appl. Sci. 2022, 12(9), 4190; https://doi.org/10.3390/app12094190 - 21 Apr 2022
Cited by 5 | Viewed by 2718
Abstract
Green agro waste can be turned into compost, which can then be used as an organic fertilizer, thus reducing the environmental impact of food and feed production. This research is focused on finding a feasible on-farm composting treatment of plant biomass to produce [...] Read more.
Green agro waste can be turned into compost, which can then be used as an organic fertilizer, thus reducing the environmental impact of food and feed production. This research is focused on finding a feasible on-farm composting treatment of plant biomass to produce high-quality compost. Three different composting treatments were prepared and followed (with different additives at the start—biochar (BC) and effective microorganisms (EM), no additive (CON); covering and not covering the pile; different start particles size). Samples were analysed for nutrient concentrations, phytotoxicity and bacterial and fungal presence after seven months of composting. In 100 g of dry matter, the average compost contained 2.7 g, 0.38 g and 1.08 g of N, P and K, respectively. All investigated treatments contained more than 2% of total nitrogen in dry mass, so they could be used as a fertilizer. The highest nutrient content was observed in compost of small particle size (˂5 cm) and added biochar (11 kg/t fresh biomass). However, this compost had the least bacteria and fungi due to very high temperatures in the thermophilic phase of this pile. According to the radish germination index, the prepared composts have no phytotoxic properties and are stable and ready to use in plant production. Taking the cress germination test into consideration, they provided a nutrient-rich and biostimulative soil amendment. All three final composts were stable in terms of respiration rate, growth and germination tests. Results have shown that hop biomass after harvest has great potential for composting. Full article
(This article belongs to the Special Issue Frontier Research in Hop)
Show Figures

Figure 1

16 pages, 3443 KiB  
Article
The Quantity and Composition of Leachate from Hop Plant Biomass during Composting Process
by Barbara Čeh, Lucija Luskar, Aleš Hladnik, Žan Trošt, Julija Polanšek and Boštjan Naglič
Appl. Sci. 2022, 12(5), 2375; https://doi.org/10.3390/app12052375 - 24 Feb 2022
Cited by 2 | Viewed by 2066
Abstract
Technology that would result in a high-quality product with minimal environmental impact throughout the on-site composting process of hop biomass after harvest has not yet been developed. It is crucial to introduce composting practices that do not result in a detrimental leachate impact. [...] Read more.
Technology that would result in a high-quality product with minimal environmental impact throughout the on-site composting process of hop biomass after harvest has not yet been developed. It is crucial to introduce composting practices that do not result in a detrimental leachate impact. Three different composting procedures that vary in terms of initial biomass particle size, additives, and pile covering were investigated. Each pile was built from 15 t of fresh hop biomass after harvest (leaves and stems), leachate was collected during the composting season (September to the end of April), and biomass was sampled and analyzed to identify good practices as well as gaps that need to be filled. Leachate quantity differed significantly in terms of the composting procedure and time stamps. There was a strong linear correlation between the amount of precipitation and leachate quantity (0.86), NH4 leached amount (0.87), and total N leached amount (0.92), but not the total P amount. The composting procedure had a significant impact on the quantity of the NH4 leached amount. The majority of the NH4 was lost in the second month of composting. The maturation phase was the most critical for NO3 loss since it had the highest amount of leached NO3 and the greatest variances among the composting protocols. Considering leachate it is recommended that a membrane is used at all times during the maturation phase as well as during any heavy precipitation expected in the thermophilic phase. Whether the cover is also needed for the entire duration of the thermophilic phase (due to emission) is a matter of further research. Full article
(This article belongs to the Special Issue Frontier Research in Hop)
Show Figures

Figure 1

19 pages, 3038 KiB  
Article
The Effect of Different Organic Foliar Fertilization on Physiological and Chemical Characters in Hop (Humulus lupulus L., cv Cascade) Leaves and Cones
by Margherita Rodolfi, Lorenzo Barbanti, Cristiana Giordano, Massimiliano Rinaldi, Andrea Fabbri, Luca Pretti, Riccardo Casolari, Deborah Beghé, Raffaella Petruccelli and Tommaso Ganino
Appl. Sci. 2021, 11(15), 6778; https://doi.org/10.3390/app11156778 - 23 Jul 2021
Cited by 5 | Viewed by 3427
Abstract
Background: Hop cultivation requires an abundant quantity of nutrients to reach higher cone yield and quality. The aim of this work was the evaluation of different fertilization plans to obtain an improvement in product quality. Methods: Foliar analysis, anatomical analysis through the use [...] Read more.
Background: Hop cultivation requires an abundant quantity of nutrients to reach higher cone yield and quality. The aim of this work was the evaluation of different fertilization plans to obtain an improvement in product quality. Methods: Foliar analysis, anatomical analysis through the use of light microscope and SEM; physiological measurements through atLEAF, Handy PEA and spectrophotometry, were carried out to determine chlorophyll content, carotenoids and photosynthetic efficiency in two periods (t1, t2) for four experimental treatments and a Control (Treat 1, Treat 2, Treat 3, Treat 4, Untreat). Leaf texture (texture analyzer), color (colorimeter), DPPH activity (spectrophotometer), bitter acid content (HPLC-UV) and essential oil yields (steam distillation) and cone yields were measured. Results: Treat 2 showed the best performance: (i) in leaves, in terms of texture, chlorophyll content and color; (ii) in cones, with 6.98% of alpha acids, 1.78% of oil yield and 3.55 kg of fresh cones per plants. Conclusion: The fertilization plans caused alteration in micro and macro elements content in hop leaves and in the composition of hop cones. In our conditions, the best fertilization plan, in terms of cone productivity and quality, was Treat 2, highlighting the value of a customized organic foliar fertilization plan for hop cultivation. Full article
(This article belongs to the Special Issue Frontier Research in Hop)
Show Figures

Figure 1

14 pages, 1080 KiB  
Article
High Genetic Diversity and Low Population Differentiation in Wild Hop (Humulus lupulus L.) from Croatia
by Martina Grdiša, Zlatko Šatović, Zlatko Liber, Jernej Jakše, Filip Varga, Renata Erhatić and Siniša Srečec
Appl. Sci. 2021, 11(14), 6484; https://doi.org/10.3390/app11146484 - 14 Jul 2021
Cited by 5 | Viewed by 2222
Abstract
Hop (Humulus lupulus L.) is used in the brewing industry as a source of compounds responsible for the bitterness, aroma, and preservative properties of beer. In this study, we used microsatellite markers to investigate genetic diversity and genetic differentiation of wild hop [...] Read more.
Hop (Humulus lupulus L.) is used in the brewing industry as a source of compounds responsible for the bitterness, aroma, and preservative properties of beer. In this study, we used microsatellite markers to investigate genetic diversity and genetic differentiation of wild hop populations sampled in the northwestern part of Croatia. Analysis of 12 microsatellite loci revealed high diversity and weak population differentiation among wild hop populations. A total of 152 alleles were determined with an average of 12.67 alleles per locus. Observed heterozygosity ranged from 0.689 to 0.839 (average 0.767) and expected heterozygosity ranged from 0.725 to 0.789 (average 0.760). A total of 38 private alleles were detected. The data suggest that H. lupulus populations are not affected by recent bottlenecks. The degree of genetic differentiation among populations was low and not significant for most pairwise FST values, except for the pair of geographically most distant populations. The results did not indicate the existence of genetic structure among the sampled populations. The high genetic diversity and low differentiation among populations, combined with the absence of isolation by distance, indicate the existence of substantial gene flow among wild hop populations. Therefore, extensive sampling per population is clearly required to assess the genetic diversity of hop populations. Sampling strategies involving sampling across a large number of localities represented by only a few samples could lead to erroneous conclusions. Full article
(This article belongs to the Special Issue Frontier Research in Hop)
Show Figures

Figure 1

18 pages, 932 KiB  
Article
Characterization of Wild Corsican Hops and Assessment of the Performances of German Hops in Corsican Environmental Conditions through a Multidisciplinary Approach
by Axel Dabbous-Wach, Margherita Rodolfi, Julien Paolini, Jean Costa and Tommaso Ganino
Appl. Sci. 2021, 11(9), 3756; https://doi.org/10.3390/app11093756 - 21 Apr 2021
Cited by 7 | Viewed by 2152
Abstract
Hops (Humulus lupulus L.) is a species that grows spontaneously in Corsica, but the characterization of this species in this territory has not yet been investigated. The main objectives of this study are to explore the features of wild hops from Corsica [...] Read more.
Hops (Humulus lupulus L.) is a species that grows spontaneously in Corsica, but the characterization of this species in this territory has not yet been investigated. The main objectives of this study are to explore the features of wild hops from Corsica and to determine the effect of the island terroir on some cultivars in the first year of growth. A multidisciplinary approach consisting of the genetic analysis, morphological comparison and chemical characterization of essential oils was carried out on four wild Corsican hops and three hop cultivars grown in Tettnang, Germany and Corsica, France. The morphological and GC-MS analysis of Corsican wild hops, set cluster coastal samples apart from the one far from the coast. This dissimilarity is supported by the SSR analysis by two of the three coastal accessions. The genetics demonstrate a proximity between the European noble cultivar Tettnanger and the mountain Corsican wild hop from Corte. The morphological comparison between German hops cultivated in Tettnang and in Corsican soil, and the GC-MS characterization of their essential oils’ chemical profiles, show different features between year 0 and year +1 for each sample. This multidisciplinary approach highlights an acclimatization of hop cultivars to the Corsican terroir one year after planting. Full article
(This article belongs to the Special Issue Frontier Research in Hop)
Show Figures

Figure 1

Back to TopTop