A bud's life: Metabarcoding analysis to characterise hazelnut big buds microbiome biodiversity.

Despite Corylus avellana L. being an economically important shrub species known for its resilience to adverse environmental conditions, it constantly faces attacks from a plethora of biotic entities. Among these, the mite pest Phytoptus avellanae is gaining importance, causing economic losses every year. This mite colonises the new generative and vegetative buds, leading them to become swollen and reddish, and drastically reducing hazelnut production. The biology behind gall formation is still poorly understood. This study provides a qualitative and quantitative description of the microbiome in both healthy and infested buds of two economically important hazelnut cultivars through metabarcoding of fungal ITS and bacterial 16 S. Potentially pathogenic genera such as Fusarium and Pseudomonas were predominant in the infested buds, along with the obligate intracellular bacterial genus Wolbachia. Akanthomyces muscarius was instead isolated from culture-based methods only from the infested buds. These findings could improve the understanding of gall ecology, supporting the management of mite populations, and they could also serve as a milestone for further studies on low-impact, monitoring-driven, and genetically targeted control strategies.

Inducing Effect of Corylus avellana on Cytotoxic Activity in Lung and Breast Cancer Cells via Apoptosis.

Turkish hazelnut (Corylus avellana L. cv Tombul) is a widely used nut in the chocolate industry and is also rich in polyphenol content, which promises anticancer effects. The anti-cancer and apoptotic effects of hazelnut leaves extracts examined on lung and breast cancer cells. Sulforhodamine B (SRB) and Adenosine 5'- triphosphate (ATP) assays were carried out for cell viability measurement. The mode of cell death was shown morphologically by the double fluorescence staining. Apoptosis was determined by performing caspase-mediated cytokeratin 18 (M30 ELISA) and western blot analysis. PARP, caspase 3, caspase 8, DR4, and GAPHD (Glyceraldehyde-3-phosphate Dehydrogenase) protein bands were visualized as markers of apoptosis. A wound healing test was employed to measure cell migration. Methanol extract of hazelnut leaf exhibited inhibition of cell growth activities in a dose-dependent manner. IC50 values were determined as 32.17 µg/ml in MCF-7, 32.16 µg/ml in MDA-MB-231, 20.40 µg/ml in A549 and 12.04 µg/ml in H1299 cells for ethanol extract while it was determined as 21.08 µg/ml in MCF-7, 40.16 µg/ml in MDA-MB-231, 22.04 µg/ml in A549 and 5.91 µg/ml in H1299 cells in methanol extract. In comparison, methanol leaf extracts were more effective in H1299 cells (IC50 value was 5.91 µg/ml).In comparison, ethanol leaf extracts were more effective in H1299 cells (IC50 value was 9.722 µg/ml). Western blot analysis demonstrated that hazelnut leaf extract treatment of cancer cells led to cell death via apoptosis and inhibited cell migration in lung and breast cancer cell lines. The cytotoxic effects of hazelnut extract on breast and lung cancer cells might be valuable and promising in elucidating cell death mechanisms for the development of new methods in cancer treatment.

Optimization of the fermentation media, mathematical modeling, and enhancement of paclitaxel production by Alternaria alternata after elicitation with pectin.

Alternaria alternata fungus is a potent paclitaxel producer isolated from Corylus avellana. The major challenge is the lack of optimized media for endophytic fungi productivity. In the effort to maximize the production of taxoids by A. alternata, several fermentation conditions, including pH (pH 4.0-7.0), different types and concentrations of carbon (fructose, glucose, sucrose, mannitol, sorbitol, and malt extract), and nitrogen (urea, ammonium nitrate, potassium nitrate, ammonium phosphate, and ammonium sulfate) were applied step by step. Based on the results, A. alternata in a medium containing sucrose 5% (w/v) and ammonium phosphate 2.5 mM at pH 6.0 showed a rapid and sustainable growth rate, the highest paclitaxel yield (94.8 µg gFW-1 vs 2.8 µg gFW-1 in controls), and the maximum content of amino acids. Additionally, the effect of pectin was evaluated on fungus, and mycelia harvested. Pectin significantly enhanced the growth and taxoid yield on day 21 (respectively 171% and 116% of their corresponding on day 7). The results were checked out by mathematical modeling as well. Accordingly, these findings suggest a low-cost, eco-friendly, and easy-to-produce approach with excellent biotechnological potential for the industrial manufacture of taxoids.

Enhancing Liquefaction Efficiency: Exploring the Impact of Pre-Hydrolysis on Hazelnut Shell (Corylus avellana L.).

Hazelnut shells (HS), scientifically known as Corylus avellana L. shells, are waste produced by companies that process nuts. The main objective of this study was to find an efficient way to maximize the chemical potential of HS by solubilizing the hemicelluloses, which could then be used to recover sugars and, at the same time, increase the lignin content of this material to produce adhesives or high-strength foams. In order to optimize the pre-hydrolysis process, two different temperatures (160 and 170 °C) and times varying from 15 to 180 min were tested. All the remaining solid materials were then liquefied using polyalcohols with acid catalysis. The chemical composition of hazelnut shells was determined before and after the pre-hydrolysis. All of the process was monitored using Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR) by determining the spectra of solids and liquids after the pre-hydrolysis and liquefaction steps. The highest solubilization of hazelnut shells was found for 170 °C and 180 min, resulting in a 25.8% solubilization. Chemical analysis after the hydrolysis process showed a gradual increase in the solubilization of hemicelluloses as both the temperature and time of the reactor were increased. Simultaneously, the percentages of α-cellulose and lignin in the material also increased with rises in temperature and duration. FTIR-ATR allowed for the detection of significant spectral changes in the hazelnut shells from their initial state to the solid residue and further into the liquefied phase. This confirmed that pre-hydrolysis was effective in enhancing the chemical composition of the material, making it more suitable for the production of adhesives, polyurethane foams, or in the production of bioplastics and composite materials, combined with other biopolymers or synthetic polymers to enhance the mechanical properties and biodegradability of the resulting materials.

Field performance of grafted, micropropagated, and own-rooted plants of three Italian hazelnut cultivars during the initial four seasons of development.

Introduction: Over the course of four consecutive years, a comparative study, for the first time, was carried out to assess their growth characteristics, vegetative and productive performances. Material: Micropropagated, grafted on not suckering rootstock and own-rooted plants by layering from three Italian hazelnut (Corylus avellana L.) cultivars were established in the same orchard and environmental condition. Results: We found that the micropropagated plants, regardless of the variety considered, even being smaller than the other plants at the beginning of the plantation, reached similar sizes as the other plants after four growing seasons. Furthermore, micropropagated plants exhibited greater uniformity in growth compared to grafted ones, while own-rooted plants displayed more variability. No significant differences in yield performance and canopy volume were observed among the three propagation methods. These results suggest that the in vitro propagation technique, even in hazelnut, allows standardizing the plant material while preserving cultivar characteristics. Finally, in vitro propagation as well as grafting can be safely recommended for the cultivation of hazelnut cultivars.

Isolation, Virtual Screening, and Evaluation of Hazelnut-Derived Immunoactive Peptides for the Inhibition of SARS-CoV-2 Main Protease.

The aim of this study is to validate the activity of hazelnut (Corylus avellana L.)-derived immunoactive peptides inhibiting the main protease (Mpro) of SARS-CoV-2 and further unveil their interaction mechanism using in vitro assays, molecular dynamics (MD) simulations, and binding free energy calculations. In general, the enzymatic hydrolysis components, especially molecular weight < 3 kDa, possess good immune activity as measured by the proliferation ability of mouse splenic lymphocytes and phagocytic activity of mouse peritoneal macrophages. Over 866 unique peptide sequences were isolated, purified, and then identified by nanohigh-performance liquid chromatography/tandem mass spectrometry (NANO-HPLC-MS/MS) from hazelnut protein hydrolysates, but Trp-Trp-Asn-Leu-Asn (WWNLN) and Trp-Ala-Val-Leu-Lys (WAVLK) in particular are found to increase the cell viability and phagocytic capacity of RAW264.7 macrophages as well as promote the secretion of the cytokines nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-1ß (IL-1ß). Fluorescence resonance energy transfer assay elucidated that WWNLN and WAVLK exhibit excellent inhibitory potency against Mpro, with IC50 values of 6.695 and 16.750 µM, respectively. Classical all-atom MD simulations show that hydrogen bonds play a pivotal role in stabilizing the complex conformation and protein-peptide interaction. Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) calculation indicates that WWNLN has a lower binding free energy with Mpro than WAVLK. Furthermore, adsorption, distribution, metabolism, excretion, and toxicity (ADMET) predictions illustrate favorable drug-likeness and pharmacokinetic properties of WWNLN compared to WAVLK. This study provides a new understanding of the immunomodulatory activity of hazelnut hydrolysates and sheds light on peptide inhibitors targeting Mpro.

Allergenicity and structural properties of new Cor a 1 isoallergens from hazel identified in different plant tissues.

The hazel allergen Cor a 1 is a PR-10 protein, closely related to the major birch pollen allergen Bet v 1. Hazel allergies are caused by cross-reactive IgE antibodies originally directed against Bet v 1. Despite the importance of PR-10 proteins in allergy development, their function and localization in the plant remain largely elusive. Therefore, the presence of Cor a 1 mRNA and proteins was investigated in different tissues, i.e., the female flower, immature and mature nuts, catkins, and pollen. Four yet unknown Cor a 1 isoallergens, i.e., Cor a 1.0501-1.0801, and one new Cor a 1.03 variant were discovered and characterized. Depending on the isoallergen, the occurrence and level of mRNA expression varied in different tissues, suggesting different functions. Interestingly, Cor a 1.04 previously thought to be only present in nuts, was also detected in catkins and pollen. The corresponding Cor a 1 genes were expressed in Escherichia coli. The purified proteins were analysed by CD and NMR spectroscopy. Immunoblots and ELISAs to determine their allergenic potential showed that the new proteins reacted positively with sera from patients allergic to birch, hazel and elder pollen and were recognized as novel isoallergens/variants by the WHO/IUIS Allergen Nomenclature Sub-Committee.

The Effect of the Periodic Drying Method on the Drying Time of Hazelnuts and Energy Utilization.

Hazelnut is a shelled fruit that is stored by drying and used as a snack or in industry. Since the hazelnut drying process is energy-intensive, there is a need for drying methods that will reduce the energy cost without lengthening the drying time. In this study, the effects of periodic drying of hazelnuts' energy recovery, oil, and protein content, as well as mass losses, were studied. Fresh Tombul hazelnuts (Corylus avellana L.) with a diameter of Ø 15-16 mm were dried in a tunnel dryer over 16 different periods by adjusting the drying time inside and waiting time outside the oven until the moisture content reached 6%. Drying experiments were carried out at 45 °C and three different air velocities. The increase in air velocity resulted in a reduction in the periodic drying time between 10% and 36%. The optimum drying in terms of drying time and energy utilization was realized at 0.5 m/s air velocity, with a 1.5 h working time and 0.5 h waiting time. During this period, drying time increased by 19% and energy utilization was 69%. For periodic drying, the increase in oven working time causes a decrease in energy utilization, while the increase in waiting time causes an increase in energy utilization and drying time. Periodic drying had no negative effect on hazelnut oil and protein content. Periodic drying is a suitable option for saving energy during hazelnut drying.

Erysiphe corylacearum as a new pathogen of hazelnut in the Czech Republic.

In July 2021, leaves and shoot tops of the common hazel (Corylus avellana L.), with a whitish coating, were found in the Czech Republic (southern Moravia region). The infected hazel bushes were found along a road in a deciduous forest and in an urban garden. In most European countries, Phyllactinia guttata is found on the abaxial surface of the leaves in the form of a continuous whitish to light grey mycelium, possibly with large black chasmothecia. In our case, the mycelium was present on both sides of the leaves, but the symptoms and the incidence were much stronger on the adaxial side. The first symptoms usually appeared on the adaxial side of the leaves as small white radially expanding patches of mycelium. In the final stage, the spots merged and covered a substantial part of the leaf blade (50-85 % on the adaxial side, 5-25 % on the abaxial side). When the abaxial side of the leaves was infected, chlorotic spots were evident on the adaxial side. The spots of powdery mildew were small (3-15 mm), whitish, rounded to irregular, effuse eventually becoming confluent, and occurred primarily on the adaxial side of the leaves. Conidiophores (30-53×4-6 µm) grew on the amphigenic mycelium, were erect, consisted of 1-3 cells, i.e. cylindrical foot cell and followed 1-2 cells, from which hyaline ellipsoid to doliform-limoniform conidia (17-34 ×15-21) (n = 50) were individually detached. Single or in groups dark brown chasmothecia (77-116 µm in diameter) had up to hyaline 8-15 aseptate straight appendages (50-102 µm) with multiple (3-5×) dichotomously branched apexes and recurved tips. Chasmothecia contained 3-6 asci (42-62 × 34-55 µm) with 4-8 obovoid to broadly ellipsoidal hyaline ascospores (14-22 × 75 µm). Based on morphological characters, the powdery mildew was identified as Erysiphe corylacearum (2). Morphological identification was confirmed by molecular analysis of samples. DNA was extracted from symptomatic leaves tissue using the DNeasy Plant Mini Kit, (Quiagen, Hilden, Germany) and the rDNA internal transcribed spacer region of 2 isolates was amplified using primers PMITS1 and PMITS2 (Cunnington et al. 2003) and sequenced. BLAST analysis of our 720bp fragments (both identical and represented by GenBank accession no. OR432526) showed 100% sequence identity to ITS rDNA sequences of E. corylacearum other countries of Central Europe for example from Austria (MW031866), Italy (MW045428), Hungary (OQ411007), Germany (OP554268) or Slovakia (MT176105). Pathogenicity was verified on two-year-old plants of Corylus avellana. Healthy leaves were artificially infected by dusting conidia from infected leaves. Inoculated plants were incubated under controlled conditions (21-23 °C, 70-80 % relative humidity). Characteristic symptoms of powdery mildew appeared on the adaxial side of the leaves 9-12 days after inoculation. Control plants treated with distilled water remained symptomless. Powdery mildew isolated from inoculated leaves was morphologically identical to isolates from naturally infected leaves. The first record of E. corylacearum in Europe on cultivated hazelnut species was reported by Sezer et al. (2017) in Turkey in 2013. Within a few years, the E. corylacearum spread and was recorded on various species of Corylus in other European countries (for example Mezzalama et al., 2020; Rosati et al., 2021; Beenken et al., 2022; Boneva et al., 2023), East Asia (Arzanlou et al., 2018) and the USA (Meparishvili 2019). To our knowledge, this is the first report of Erysiphe corylacearum in the Czech Republic.

Occurrence of powdery mildew caused by Erysiphe corylacearum on Hazelnuts in Israel.

Hazelnut (Corylus avellana L) is an emerging crop in Israel, primarily cultivated as a host plant to establish truffle plantations through symbiosis with ectomycorrhizal fungi. A significant damage and yield reduction is caused by the prevalent occurrence of powdery mildew in hazelnut trees (Sezer et al., 2017). Until recently, Phyllactinia guttata was considered the primary pathogen in Western Asia, the Caucasus region, and Europe (Abasova et al. 2018; Arzanlou et al. 2018; Mezzalama et al. 2021). However, in the last years, a new destructive species Erysiphe corylacearum has been identified as the pathogen of powdery mildew on hazelnuts in these regions (Meparishvili et al. 2019; Mezzalama et al. 2021; Kalmár et al. 2022; Zajc et al. 2023). In May 2022, powdery mildew symptoms were observed on hazelnut plants in the Ein-Zivan truffle plantation, gardens of Merom-Golan, and the adjacent garden of the packing house Pri-Beresheet in the northern Golan region of Israel. Symptoms were observed on the abaxial and adaxial leaf surfaces, fruits, and husks. Disease incidence and severity ranged between 30-70% and 5-90%, respectively. Disease severity was significantly greater on the leaves of the offshoots compared to those on the tree canopy. Morphological characterization of leaf samples from ten different trees showed the following characteristics: hyphal appressoria were lobed, solitary, 1-4 µm in diameter; mycelium was amphigenous, hyaline, and septate; conidiophores vertically elevated from the mycelium 50- 80 µm long. Conidia (n= 30) on conidiophores were hyaline, ellipsoid to ovoid, 24 - 34 µm long and 15.5 - 23 µm wide. Chasmothecia in several maturation degrees appeared in October on both sides of the leaves. They were spherical (n= 30) 86 - 125 µm in diameter, with 7 - 14 aseptate straight appendages, 67 - 96 µm long, 4.9 - 7.1 µm wide, dichotomous branched at the end 42 - 56 µm wide. In each chasmothecia, there were 3-5 asci (n=30) with a width of 38 - 43 µm and a length of 48-64 µm of oval-ellipsoid shape. Asci contained 4-8 ascospores (n=30), 18 - 26 µm long and 11 - 15.5 µm wide. A pathogenicity test was conducted to fulfill Koсh's postulates. Both detached leaves and plants of C. avellana were artificially infected by brushing conidia from infected leaves. Inoculated leaves in Petri dishes on 2% water agar (n= 5), and plants (n= 5) were incubated under 25°C and 12-h photoperiod/day. Untreated leaves and plants served as control. Typical symptoms appeared on the upper surface of the leaves within 7-10 days after inoculation. No symptoms were found on untreated control plants or detached leaves. The fungus isolated from the inoculated leaves was morphologically identical to the original isolates from natural diseased plants. DNA was extracted and the rDNA internal transcribed spacer region of five isolates originated from leaves of the tree canopy and offshoots was amplified using primers ITS1 and ITS4, and sequenced. BLAST analysis of 595 bp fragments (all identical and represented by isolate Cora1, GenBank Accession No. OR752437) showed 99% identity to ITS rDNA sequences of E. corylacearum from Georgia (MK157199) and 100% identity to isolates from Azerbaijan, Turkey and Italy (LC270863, KY082910 and MW045425, respectively) and only 83% similarity to P. guttata (accession number AB080558). To the best of my knowledge this is the first report on E. corylacearum causing powdery mildew in Israel. Future control measures to manage the disease on hazelnuts in truffle plantations in Israel should be considered.

The ethanolic extract of Corylus avellana L. drives a microRNA-based cytotoxic effect on HepG2 hepatocarcinoma cells.

An ethanolic extract of Corylus avellana L. hazelnut was characterised by liquid chromatography coupled to high resolution mass spectrometry. We here evaluated the in vitro cytotoxic response to such extract in HepG2 cells and tried to depict the underlying mechanism(s) in terms of microRNA-34b/c involvement. Following long-term exposure (144h) of HepG2 cells with 0.04-0.4 mg/ml of hazelnut extract, we demonstrated that miR-34 precursor RNA and both mature miR-34b and miR-34c molecules underwent a significant stimulation (>2-fold change, p < 0.05) in cells treated with the highest concentration. The epigenetic modulation was accompanied by the inhibition of cell proliferation, the decrease of viability and activation of apoptosis at 144h of treatment with 0.4 mg/ml of hazelnut.These in vitro findings demonstrate the cytotoxic effect of the C. avellana extract in HepG2 cells and open the way to in vivo validation of possible application of hazelnut-based extracts, and/or its metabolites, as promising epigenetics drugs.

Terahertz imaging for non-invasive classification of healthy and cimiciato-infected hazelnuts.

The development of new non-invasive approaches able to recognize defective food is currently a lively field of research. In particular, a simple and non-destructive method able to recognize defective hazelnuts, such as cimiciato-infected ones, in real-time is still missing. This study has been designed to detect the presence of such damaged hazelnuts. To this aim, a measurement setup based on terahertz (THz) radiation has been developed. Images of a sample of 150 hazelnuts have been acquired in the low THz range by a compact and portable active imaging system equipped with a 0.14 THz source and identified as Healthy Hazelnuts (HH) or Cimiciato Hazelnut (CH) after visual inspection. All images have been analyzed to find the average transmission of the THz radiation within the sample area. The differences in the distribution of the two populations have been used to set up a classification scheme aimed at the discrimination between healthy and injured samples. The performance of the classification scheme has been assessed through the use of the confusion matrix on 50 samples. The False Positive Rate (FPR) and True Negative Rate (TNR) are 0% and 100%, respectively. On the other hand, the True Positive Rate (TPR) and False Negative Rate (FNR) are 75% and 25%, respectively. These results are relevant from the perspective of the development of a simple, automatic, real-time method for the discrimination of cimiciato-infected hazelnuts in the processing industry.

Food Monitoring: Limitations of Accelerated Storage to Predict Molecular Changes in Hazelnuts (Corylus avellana L.) under Realistic Conditions Using UPLC-ESI-IM-QTOF-MS.

Accelerated storage is routinely used with pharmaceuticals to predict stability and degradation patterns over time. The aim of this is to assess the shelf life and quality under harsher conditions, providing crucial insights into their long-term stability and potential storage issues. This study explores the potential of transferring this approach to food matrices for shelf-life estimation. Therefore, hazelnuts were stored under accelerated short-term and realistic long-term conditions. Subsequently, they were analyzed with high resolution mass spectrometry, focusing on the lipid profile. LC-MS analysis has shown that many unique processes take place under accelerated conditions that do not occur or occur much more slowly under realistic conditions. This mainly involved the degradation of membrane lipids such as phospholipids, ceramides, and digalactosyldiacylglycerides, while oxidation processes occurred at different rates in both conditions. It can be concluded that a food matrix is far too complex and heterogeneous compared to pharmaceuticals, so that many more processes take place during accelerated storage, which is why the results cannot be used to predict molecular changes in hazelnuts stored under realistic conditions.

Specific and sensitive detection tools for Xanthomonas arboricola pv. corylina, the causal agent of bacterial blight of hazelnut, developed with comparative genomics.

Xanthomonas arboricola pv. corylina (Xac; formerly Xanthomonas campestris pv. corylina) is the causal agent of the bacterial blight of hazelnuts, a devastating disease of trees in plant nurseries and young orchards. Currently, there are no PCR assays to distinguish Xac from all other pathovars of X. arboricola. A comparative genomics approach with publicly available genomes of Xac was used to identify unique sequences, conserved across the genomes of the pathogen. We identified a 2,440 bp genomic region that was unique to Xac and designed identification and detection systems for conventional PCR, qPCR (SYBR® Green and TaqMan™), and loop-mediated isothermal amplification (LAMP). All PCR assays performed on genomic DNA isolated from eight X. arboricola pathovars and closely related bacterial species confirmed the specificity of designed primers. These new multi-platform molecular diagnostic tools may be used by plant clinics and researchers to detect and identify Xac in pure cultures and hazelnut tissues rapidly and accurately.

Molecular Characterization and Pathogenicity of Diaporthe Species Causing Nut Rot of Hazelnut in Italy.

Hazelnut (Corylus avellana), a nut crop that is rapidly expanding worldwide, is endangered by a rot. Nut rot results in hazelnut defects. A survey was conducted in north-western Italy during 2020 and 2021 to identify the causal agents of hazelnut rots. Typical symptoms of black rot, mold, and necrotic spots were observed on hazelnut nuts. The prevalent fungi isolated from symptomatic hazelnut kernels were Diaporthe spp. (38%), Botryosphaeria dothidea (26%), Diplodia seriata (14%), and other fungal genera with less frequent occurrences. Among 161 isolated Diaporthe spp., 40 were selected for further analysis. Based on morphological characterization and multi-locus phylogenetic analysis of the ITS, tef1- α, and tub2, seven Diaporthe species were identified as D. eres, D. foeniculina, D. novem, D. oncostoma, D. ravennica, D. rudis, and D. sojae. D. eres was the main species isolated from hazelnut rots, in particular from moldy nuts. Pathogenicity test performed on hazelnut nuts 'Tonda Gentile del Piemonte' using a mycelium plug showed that all the Diaporthe isolates were pathogenic on their original host. To our knowledge, this work is the first report of D. novem, D. oncostoma and D. ravennica on hazelnut nuts worldwide. Diaporthe foeniculina, D. rudis, and D. sojae were reported for the first time as agents of hazelnut nut rot in Italy. Future studies should focus on the comprehension of epidemiology and climatic conditions favoring the development of Diaporthe spp. on hazelnut. Prevention and control measures should target D. eres, representing the main causal agents responsible for defects and nut rot of hazelnuts in Italy.

Corylus avellana "Nocciola Piemonte": metabolomics focused on polar lipids and phenolic compounds in fresh and roasted hazelnuts.

The common hazel plant (Corylus avellana L., Betulaceae) is one of the most popular tree nuts widespread in Europe and Asia. In Italy, there are different cultivars among which the cultivar affording the valuable hazelnut "Tonda Gentile Trilobata," also known as "Tonda Gentile delle Langhe," covered by the Protected Geographical Indication (PGI) label "Nocciola Piemonte" (NP), known for its sweetness, cooked-bread aroma, and the low intensity of the burnt aroma. In order to obtain a detailed and in-depth characterization of the polar fraction of fresh (NPF) and roasted (NPR) kernels of NP the analysis of the n-butanol extracts by liquid chromatography coupled to electrospray ionization and high-resolution mass spectrometry (LC-ESI/HRMS) was carried out. Moreover, to evaluate the quantitative distribution of the most representative polar lipids in NPF and NPR, the analysis by liquid chromatography combined with tandem mass spectrometry (LC-MS/MS) was performed. To unambiguously identify the phenolic compounds highlighted by the LC-ESI/HRMS profiles, they were isolated from the n-butanol extract and characterized by Nuclear Magnetic Resonance (NMR) experiments. Finally, the ability of the isolated compounds to exert radical scavenging activity and to inhibit the lipid peroxidation induced by H2O2 or H2O2/Fe2+ was tested by Trolox Equivalent Antioxidant Capacity (TEAC) and thiobarbituric acid reactive substances (TBARS) assays, respectively. The LC-ESI/HRMS allowed to ascertain the presence of phenolic compounds and multiple classes of polar lipids including phospholipids, glycolipids, sphingolipids, and oxylipins. The quantitative analysis highlighted in NPR fraction a lipid content three times higher than in NPF, evidencing lyso-phospholipids and phospholipids as the most represented lipid classes in both NPF and NPR, together accounting for 94 and 97% of the considered lipids, respectively. Furthermore, phytochemical analysis permitted to identify flavonoid and diarylheptanoid derivatives. In particular, quercetin 3-O-ß-D-galactopyranosyl-(1→2)-ß-D-glucopyranoside and myricetin-3-O-α-L-rhamnopyranoside showed the highest antioxidant activity, exhibiting TEAC values similar to that of quercetin, used as reference compound (2.00 ± 0.03 and 2.06 ± 0.03 mM vs 2.03 ± 0.03 mM, respectively). Moreover, most of the tested compounds were found to reduce lipid peroxidation induced by H2O2 and H2O2/Fe2+ more than curcumin used as positive control, with myricetin-3-O-α-L-rhamnopyranoside determining 44.4 % and 34.1 % inhibition percentage, respectively.

Corrigendum: Epidemiology of flavescence dorée and hazelnut decline in Slovenia: geographical distribution and genetic diversity of the associated 16SrV phytoplasmas.

[This corrects the article DOI: 10.3389/fpls.2023.1217425.].

Epidemiology of flavescence dorée and hazelnut decline in Slovenia: geographical distribution and genetic diversity of the associated 16SrV phytoplasmas.

Flavescence dorée (FD) phytoplasma from 16SrV-C and -D subgroups cause severe damage to grapevines throughout Europe. This phytoplasma is transmitted from grapevine to grapevine by the sap-sucking leafhopper Scaphoideus titanus. European black alder and clematis serve as perennial plant reservoirs for 16SrV-C phytoplasma strains, and their host range has recently been extended to hazelnuts. In Slovenia, hazelnut orchards are declining due to 16SrV phytoplasma infections, where large populations of the non-autochthonous leafhopper Orientus ishidae have been observed. To better characterise the phytoplasma-induced decline of hazelnut and possible transmission fluxes between these orchards and grapevine, genetic diversity of 16SrV phytoplasmas in grapevine, hazelnut and leafhoppers was monitored from 2017 to 2022. The nucleotide sequence analysis was based on the map gene. The most prevalent map genotype in grapevine in all wine-growing regions of Slovenia was M54, which accounted for 84% of the 176 grapevines tested. Besides M54, other epidemic genotypes with lower frequency were M38 (6%), M51 (3%), M50 (2%) and M122 (1%). M38, M50 and M122 were also detected in infected cultivated hazelnuts and in specimens of O. ishidae leafhopper caught in declining hazelnut orchards. It suggests that this polyphagous vector could be responsible for phytoplasma infection in hazelnut orchards and possibly for some phytoplasma exchanges between hazelnuts and grapevine. We hereby describe new genotypes: M158 in grapevine as well as four never reported genotypes M159 to M162 in hazelnut. Of these four genotypes in hazelnut, one (M160) was also detected in O. ishidae. Analysis of additional genes of the new genotypes allowed us to assign them to the VmpA-III cluster, which corresponds to the 16SrV-C strains previously shown to be compatible with S. titanus transmission.

Hazelnut (Corylus avellana L.) shells as a potential source of dietary fibre: impact of hydrothermal treatment temperature on fibre structure and degradation compounds.

BACKGROUND: Hemicellulose extraction from lignocellulosic biomasses has gained interest over the years, and hydrothermal treatment is one of the most common methods employed for this purpose. This work aimed to deeply study hazelnut (Corylus avellana L.) shells as a new source of dietary fibre, evaluating the effect of hydrothermal treatment temperatures on the type and structure of fibre extracted, but also on the formation of side-products derived from lignocellulose degradation. RESULTS: Different process temperatures led to diverse polysaccharides in the hydrothermal extract. Pectin was identified for the first time in hazelnut shells when experimenting with extraction at 125 °C, whereas at 150 °C a heterogeneous mixture of pectin, xylan, and xylo-oligosaccharides was present. The highest yield in terms of total fibre was gained at 150 and 175 °C, and then decreased again at 200 °C. Finally, more than 500 compounds from different chemical classes were putatively identified and they appeared to be present in the extracted fibre with a different distribution and relative amount, depending on the heat treatment severity. A generally high content of phenols, phenyls, oligosaccharides, dehydro-sugars, and furans was observed. CONCLUSIONS: Modulation of the hydrothermal treatment temperature allows fibre extracts with very different compositions, and therefore different potential end uses, to be obtained from hazelnut shells. A sequential temperature-based fractionation approach, as a function of the severity of the extraction parameters, can also be considered. Nevertheless, the study of the side-compounds formed from lignocellulosic matrix degradation, as a function of the applied temperature, needs to be fully addressed for a safe introduction of the fibre extract within the food chain. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

A geographical origin assessment of Italian hazelnuts: Gas chromatography-ion mobility spectrometry coupled with multivariate statistical analysis and data fusion approach.

Hazelnut is a commodity that has gained interest in the food science community concerning its authenticity. The quality of the Italian hazelnuts is guaranteed by Protected Designation of Origin and Protected Geographical Indication certificates. However, due to their modest availability and the high price, fraudulent producers/suppliers blend, or even substitute, Italian hazelnuts with others from different countries, having a lower price, and often a lower quality. To contrast or prevent these illegal activities, the present work investigated the application of the Gas Chromatography-Ion mobility spectrometry (GC-IMS) technique on the hazelnut chain (fresh, roasted, and paste of hazelnuts). The raw data obtained were handled and elaborated using two different ways, software for statistical analysis, and a programming language. In both cases, Principal Component Analysis and Partial Least Squares-Discriminant Analysis models were exploited, to study how the Volatile Organic Profiles of Italian, Turkish, Georgian, and Azerbaijani products differ. A prediction set was extrapolated from the training set, for a preliminary models' evaluation, then an external validation set, containing blended samples, was analysed. Both approaches highlighted an interesting class separation and good model parameters (accuracy, precision, sensitivity, specificity, F1-score). Moreover, a data fusion approach with a complementary methodology, sensory analysis, was achieved, to estimate the performance enhancement of the statistical models, considering more discriminant variables and integrating at the same time further information correlated to quality aspects. GC-IMS could be a key player as a rapid, direct, cost-effective strategy to face authenticity issues regarding the hazelnut chain.