13004 research outputs found
Sort by
The use of Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS) to determine the Volatile Organic Compounds (VOCs) produced by different lactic acid bacterial strains growing in defined media
Get PDFLactic acid bacteria (LAB) fermentation has been claimed as an effective way of modifying the sensory properties of plant-based foods. However, not much has been published on the influence of different LAB strains on the flavour of the volatile organic compounds (VOCs) produced. Using a defined medium (DM) and proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS), we assessed the VOCs produced by seven LAB strains, Levilactobacillus brevis WLP672 (LB672), Lactobacillus delbrueckii WLP677 (LD677), Pediococcus damnosus WLP661 (PD661), Lactiplantibacillus plantarum LP100 (LP100), Pediococcus pentosaceus PP100 (PP100), Pediococcus damnosus 5733 (PD5733), and Lentilactobacillus buchneri 5335 (LU5335), at three time points during fermentation (0, 7, and 14 days) at either 25 or 35 °C. Significant variations in VOC production were observed among LAB strains, growing in the same DM composition at either 25 °C or 35 °C. Specifically, the concentration of m/z 87.043 (t.i. diacetyl) was significantly (p < 0.05) higher at 7 days of fermentation at 35 °C by LP100, followed by PP100 at 35 °C and PD661 at 25 °C compared to the other strains at either 25 or 35 °C. The concentration of m/z 115.112 (t.i. 2-heptanone) was significantly (p < 0.05) higher at 7 days of fermentation at either 25 or 35 °C by LP100 compared to the other strains at all temperature and time points. The concentration of m/z 49.011 (t.i. methanethiol) was significantly (p < 0.05) higher after 7 days of fermentation at 35 °C by LB672 compared to the other strains at either 25 or 35 °C. The concentration of m/z 71.085 (t.i. 3-methyl butanol) was significantly (p < 0.05) higher after 7 days of fermentation at either 25 or 35 °C by PD661, LU5335, or PD5733 compared to the other strains studied. A notable increase in specific VOC concentrations was observed at 35 °C compared to 25 °C. This research demonstrates that LAB strains generate distinct VOC profiles in a DM based on strains and fermentation conditions. Therefore, this knowledge provides a basis for controlling and enhancing flavour in plant-based fermentation
Developing a new panel of genomic loci for mammalian taxonomic identification: MIPs (Multi-locus Intron Polymorphisms)
No full textRapid species identification is a fundamental tool for wildlife management and conservation plans. Many molecular methods have been proposed to solve taxonomic issues, such microsatellites (STR), or SNP (Single Nucleotide Polymorphisms) sets generated from RAD-seq and GBS (Genotyping-by- Sequencing). However, these markers tend to be species specific (STR) or cannot be efficiently applied to samples with scarce DNA quality/quantity (RAD-seq and GBS). Here we developed a new panel of Multi-locus Intron Polymorphisms ('MIPs') for mammalian genomic surveys, species and individual identification, and monitoring of interspecific hybridization. Specific subsets for rodents, lagomorphs, canids and their hybrids were designed. To generate a panel maximizing levels of cross-amplification, 121 available genomes from across Mammalia were aligned to identify the most conserved intronic regions; 192 introns randomly distributed across the genomes were then selected for the panel. Primer pairs suitable for multiplex PCR amplifications followed by Illumina amplicon sequencing were designed on conserved exonic flanking regions. The MIPs panel was tested on 71 laboratory mouse tissue samples to assess its potential to identify two parental lineages (Mus musculus musculus and M. m. domesticus) and different hybrid classes obtained from controlled laboratory crosses. The panel was then tested on invasive samples from several pairs of species known to hybridize under natural conditions: tissue samples from 250 mountain hares (Lepus timidus) and 70 brown hares (L. europaeus) bagged in the Province of Sondrio (Italy), from three hunting areas with different intensities of L. europaeus restocking, two altitudinal ranges (below and above 2000 m a.s.l.) and two collection periods (2001–2008 and 2016–2023) as proxies for climate change scenarios. Further tests were also conducted on other mammalian species belonging to the families Bovidae, Canidae, Felidae, and Suidae. Amplicon sequencing data were analysed with dedicated bioinformatic pipelines to assess inter- and intraspecific genetic diversity and level of hybridization of the populations under study. We discuss the usefulness of MIPs in addressing taxonomic problems and defining hybridization classes between different mammalian species
Buoni risultati "fertilizzanti" dal digestato essiccato
No full textIl digestato essiccato proveniente da un biodigestore alimentato con effluenti bovini e silomais ha dato risultati vegeto-produttivi analoghi a quelli di un concime minerale specifico per l’orticoltura su pomodoro da industria, mentre su bieta seminata i risultati non sono stati buoni a causa del contatto diretto (da evitare) con le radic
Investigating the role of sampler compartments employed by POCIS devices in pesticides sampling
Get PDFPolar Organic Chemical Integrative Sampler (POCIS) is a passive sampler employed to monitor organic compounds in water (e.g. pesticides, drugs, etc.); in our case consists of a receiving phase, Oasis HLB, enclosed between two polyethersulfone (PES) membranes. In most cases, the analytes were extracted only from the receiving phase but recent works show that some compounds were also adsorbed on the PES membranes. Many aspects on the membrane behaviour are still unknown and this work aims to fill some knowledge gaps exploring the capability of PES membranes to adsorb pesticides. From experiments conducted in a controlled environment, it was seen that more than half of the investigated compounds were adsorbed more effectively by the PES membrane than the Oasis HLB phase. The affinity of these pesticides towards the two sampler compartments, can be explained only partially by the polarity of the compounds. However, a significant adsorption of the most hydrophobic compounds by the PES membrane was noticed, especially for values of LogKow higher than 4. From these experiments, it was possible to calibrate POCIS by comparing the pesticide concentration in water with the amount adsorbed by the two sampler compartments over time, with the estimation of two values of sampling rate for each pesticide (RS,HLB and RS,PES). It was seen that the combination of the two adsorbent substrates allowed to intercept almost all the studied compounds satisfactorily and this behaviour was also confirmed by a field sampling campaign
Insight on Lugana flavor with a new LC-MS method for the detection of polyfunctional thiols
No full textThe analysis of important aroma compounds, such as polyfunctional thiols, requires a reliable and straightforward method. Despite advances in odorant detection, each method currently involves lengthy and complex sample preparation. In this paper, we present a novel high-throughput method that includes derivatization with ebselen, SPE purification, and LC-MS analysis for the quantification of 15 thiols with enological relevance, as well as its comparison with a recently developed QuEChERS-based method. Furthermore, the analysis of 43 Lugana wines was conducted to gain insight into the thiolic composition of this typical Italian wine characterized by tropical flavors and to demonstrate the efficacy of this fast, reliable, and environmentally friendly metho
Insight on tannin extraction and mechanical changes during maceration from skins and seeds of Italian red grape varieties
Get PDFThis study investigated tannin extraction in four Italian red grape varieties — ‘Aglianico’, ‘Nebbiolo’, ‘Primitivo’, and ‘Sangiovese’. The grape initial tannin content was characterized through a potential extraction. Moreover, the extractable phenolic content was evaluated through maceration in wine-like solution of skins, seeds, and their combinations for 10 days, with ethanol concentration incrementally adjusted to simulate fermentation. Texture analysis of grape seeds and skins was conducted before and after the wine-like solution macerations. Results revealed variety-dependent differences in the mechanical and acoustic properties of grape skins and seeds, with seeds showing increased acoustic energy upon breakage. Grape varieties showed differences in skin and seed phenolic pools and extractability. Significant positive correlations were found between potential and extractable tannin content. Smaller, less galloylated flavan-3-ols were well extracted in model wine solutions. Extraction curves were examined from skins, seeds, and combined skins + seeds matrices, evidencing a faster skin phenolics extraction than seeds. Interestingly, tannin extraction from skins + seeds did not correspond to the sum of individual skin and seed extractions. Moreover, the skin-to-seed tannin ratio and tannin structural characteristics also varied between skin and seed joint and separate extraction
l(+)-tartaric acid of grape origin: Definition of threshold limits for the 13C/12C and 18O/16O stable isotope ratios and validation of the isotopic method through an interlaboratory study
Get PDFL(+)-tartaric acid is one of the most used additives in the oenological practices. Its properties make it useful as preservative and acidulant in grape-derived products. This additive can be obtained through the extraction from grapes, from other fruits or through synthesis from petrochemical sources. In Europe, only L(+)-tartaric acid from grapes can be added to wine products, but the price difference between the forms could lead to the fraudulent use of the cheaper synthetic L(+)-tartaric acid. In other continents where such limitation is not applied, the clear commercial identification of the products is still desirable. Stable isotope analysis of carbon (δ13C) and oxygen (δ18O) proved to be a robust and effective method in discriminating between synthetic and grape-derived L (+)-tartaric acid. In this study, to define the threshold limits of δ13C (above − 24.8 ‰) and δ18O (above +25.6 ‰) of grape-derived L(+)-tartaric acid, a database consisting of 81 authentic natural samples was created. Moreover, the validation of the isotopic method through an interlaboratory study involving nine European and extraEuropean laboratories, was provided. The repeatability and the reproducibility standard deviation of the method were calculated
European consumers' involvement with date labels and implications for household food waste
Get PDFFood waste (FW) in the European Union remains a significant challenge, with over 58 million tons generated annually. Consumer behavior, particularly in relation to food-date labels, is a key factor influencing FW. This study focuses on patterns of involvement with date labels, examining how understanding, attention, and behavioral responses to date labels vary across consumer segments. By clustering consumers based on these dimensions, the research aims to identify distinct involvement patterns toward date labels and the impact on FW decisions. The study involved 1507 consumers (54.6 % female, mean age = 44.9 years) from six EU countries (Belgium, France, Germany, Italy, Spain, Sweden). Participants completed an online questionnaire assessing their understanding, attention, and behavioral responses to date labels, alongside their reported domestic FW behaviors, sociodemographics, and FW management skills. Results indicate that 75.2 % of European consumers understand the difference between ‘use by’ and ‘best before’ dates, and over 80 % correctly identify the meanings of these terms. Increased understanding correlates with reduced household FW, but this factor alone is insufficient to significantly lower waste levels. Additionally, enhanced use of date labels plays a crucial role in minimizing FW. The study identifies distinct consumer segments toward date labels: “Higher involvement” segment (23.9 % of subjects), who rely on date labels for food management, “Lower involvement” segment (33.4 %), who base their decisions on other elements such as sensory cues, and “Medium involvement” segment (42.6 %), which shows intermediate characteristics. This segmentation provides valuable insights for designing targeted interventions aimed at improving date label usage and reducing household F