Effects of Thermal and High-Pressure Processing on Quality Features and the Volatile Profiles of Cloudy Juices Obtained from Golden Delicious, Pinova, and Red Delicious Apple Cultivars

In this study, juices extracted from three apple cultivars (Golden Delicious, Pinova, and Red Delicious) were stabilized by means of thermal treatment (TT) and high-pressure processing (HPP, 600 MPa 3 min); pH, total titratable acidity, total soluble solids content, color, and viscosity, as well as volatile profile, were investigated. Qualitative characteristics (pH, titratable acidity, colorimetric parameters, viscosity, and volatile profile) results were significantly influenced by both cultivars and treatments; for example, juice viscosity greatly increased after HPP treatment for Golden Delicious, and after both TT and HPP for Pinova, while no influence of stabilization treatment was registered for Red Delicious juices. Regarding the volatile profile, for Golden Delicious cultivar, HPP treatment determined an increase in volatile compounds for most of the classes considered, leading to a supposed quality implementation. For the other two cultivars, the stabilization treatment that better preserved the volatile profile was the HPP one, even if the results were quite similar to the thermal treatment. Further studies are needed to evaluate different time/pressure combinations that could give better results, depending on the specific apple cultivar

In vitro leaf-derived organogenesis and somaclonal variant detection in Humulus lupulus L

The exploitation of somaclonal variation potentially could be a valid strategy to overcome the depletion of hop intraspecific agrobiodiversity. To increase somaclonal variation induction, it is possible to resort to several strategies including a differentiated starting explant material such as leaves, roots and stems, an extended time in which cultures are maintained in vitro, and a wellbalanced cytokinin/auxin ratio. In this research, firstly, the influence of growth regulator type and concentration and the effect of the period of in vitro hop leaf culture (6, 12, and 18 wk) were investigated. Secondly, cytofluorimetric and Random Amplification of Polymorphic DNA (RAPD) analyses were carried out to verify the occurrence of somaclonal variation. Adventitious shoots were obtained in all media containing 6-benzylaminopurine (BAP) (except BAP at lowest concentration tested), with no influence detected by culture period. Mutants were detected among regenerants (16.8%) with more than half of the tetraploids obtained from medium containing the highest BAP concentration (35.55 mM). Mutants detected by RAPD analysis were independent of the medium composition and time in culture. A strong influence regarding explant was observed where nearly half of mutants obtained originated from cultured leaf tissues. Further studies are needed to characterize the field performance of mutants

Phenological phases of flowering in hop (Humulus lupulus L.) and their correspondence with microsporogenesis and microgametogenesis

[EN] Hop (Humulus Lupulus L.) suffered, as many other crops, a shrinkage of its intraspecific agrobiodiversity. Biotechnological methods of breeding would offer new opportunities to produce improved varieties with interesting phytochemical profiles and adaptable to the challenging conditions of climate change. Doubled haploid (DH) technology could be a useful tool to increase hop agrobiodiversity but, unfortunately, there is a complete lack of information about hop flower biology. For this reason, the main aim of this work is the study of the different phenological phases of flowering in hop and the corresponding developmental stages of microspores/pollen grains contained therein. The results obtained allowed the identification of morphological markers (anther and flower bud length), easy and fast to measure, that would speed up the selection of flower buds containing the highest percentage of vacuolated microspores and young pollen, the stages considered in most species as the most responsive to androgenesis. A further result, derived from the flower bud and anther microscopical observation, evidenced the increase of lupulin glands on bud and anther surface as the bud proceeds in development from microsporogenesis to microgametogenesis.This work was supported by Spanish MINECO [grant number AGL2017-88135-R to JMSS] jointly funded by FEDER.Liberatore, C.; Calabuig-Serna, A.; Rodolfi, M.; Chiancone, B.; Seguí-Simarro, JM. (2019). Phenological phases of flowering in hop (Humulus lupulus L.) and their correspondence with microsporogenesis and microgametogenesis. Scientia Horticulturae. 256:1-6. https://doi.org/10.1016/j.scienta.2019.108639S16256Easterling, K. A., Pitra, N. J., Jones, R. J., Lopes, L. G., Aquino, J. R., Zhang, D., … Bass, H. W. (2018). 3D Molecular Cytology of Hop (Humulus lupulus) Meiotic Chromosomes Reveals Non-disomic Pairing and Segregation, Aneuploidy, and Genomic Structural Variation. Frontiers in Plant Science, 9. doi:10.3389/fpls.2018.01501Nagel, J., Culley, L. K., Lu, Y., Liu, E., Matthews, P. D., Stevens, J. F., & Page, J. E. (2008). EST Analysis of Hop Glandular Trichomes Identifies an O-Methyltransferase That Catalyzes the Biosynthesis of Xanthohumol. The Plant Cell, 20(1), 186-200. doi:10.1105/tpc.107.055178Parra-Vega, V., González-García, B., & Seguí-Simarro, J. M. (2012). Morphological markers to correlate bud and anther development with microsporogenesis and microgametogenesis in pepper (Capsicum annuum L.). Acta Physiologiae Plantarum, 35(2), 627-633. doi:10.1007/s11738-012-1104-xPatzak, J., Nesvadba, V., Henychová, A., & Krofta, K. (2010). Assessment of the genetic diversity of wild hops (Humulus lupulus L.) in Europe using chemical and molecular analyses. Biochemical Systematics and Ecology, 38(2), 136-145. doi:10.1016/j.bse.2009.12.023Patzak, J., Nesvadba, V., Krofta, K., Henychova, A., Marzoev, A. I., & Richards, K. (2010). Evaluation of genetic variability of wild hops (Humulus lupulus L.) in Canada and the Caucasus region by chemical and molecular methods. Genome, 53(7), 545-557. doi:10.1139/g10-024Salas, P., Rivas-Sendra, A., Prohens, J., & Seguí-Simarro, J. M. (2011). Influence of the stage for anther excision and heterostyly in embryogenesis induction from eggplant anther cultures. Euphytica, 184(2), 235-250. doi:10.1007/s10681-011-0569-9Seguí-Simarro, J. M. (2010). Androgenesis Revisited. The Botanical Review, 76(3), 377-404. doi:10.1007/s12229-010-9056-6Seguí-Simarro, J. M., & Nuez, F. (2005). Meiotic metaphase I to telophase II as the most responsive stage during microspore development for callus induction in tomato (Solanum lycopersicum) anther cultures. Acta Physiologiae Plantarum, 27(4), 675-685. doi:10.1007/s11738-005-0071-xSHEPHARD, H. L., PARKER, J. S., DARBY, P., & AINSWORTH, C. C. (2000). Sexual development and sex chromosomes in hop. New Phytologist, 148(3), 397-411. doi:10.1046/j.1469-8137.2000.00771.xXie, W., Xiong, W., Pan, J., Ali, T., Cui, Q., Guan, D., … Davis, S. J. (2018). Decreases in global beer supply due to extreme drought and heat. Nature Plants, 4(11), 964-973. doi:10.1038/s41477-018-0263-