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Comparison of Gas and Liquid Chromatography (GC, LC) coupled with Isotope Ratio Mass Spectrometry (IRMS): a case study on rice amino acids
Get PDFCompound-Specific Isotope Analysis (CSIA) of amino acids (AAs) is increasingly applied in food authentication and environmental studies, where precise and accurate δ13C measurements are essential. This study systematically compares the performance of Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry (GC-C-IRMS) and Liquid Chromatography coupled to Isotope Ratio Mass Spectrometry (LC-co-IRMS) for δ13C analysis of essential and non-essential AAs. The GC-C-IRMS showed high analytical precision, with standard deviations typically below 0.5 ‰ for standard AAs and 0.8 ‰ for rice samples, in close agreement with EA-IRMS reference values. The LC-co-IRMS, while generally reliable, exhibited higher variability, with deviations up to 1.6 ‰ for standard AAs and 1.9 ‰ for samples. The GC-C-IRMS also provided better chromatographic resolution, shorter run times, and broader amino acid coverage but involved complex workflows, including derivatization and the use of hazardous reagents. In contrast, LC-co-IRMS offered a simpler, safer protocol with fewer correction steps, though with longer analysis times, reduced throughput, and higher water consumption. Despite these trade-offs, both methods yielded comparable δ13C values overall, with some differences for specific AAs. This study finds GC-C-IRMS as suitable for high-precision, high-throughput applications, while LC-co-IRMS is more appropriate for simplified, sustainable workflows, with method selection depending on research purposes and operational prioritie
Rapid profiling of volatile organic compounds associated with plant-based milks versus bovine milk using an integrated PTR-ToF-MS and GC-MS approach
Get PDFThe growing demand for plant-based beverages has underscored the importance of investigating their volatile profiles, which play a crucial role in sensory perception and consumer acceptance. This is especially true for plant-based milks (PBMs) that have a clear reference model in bovine milk. This study characterises the volatile organic compounds (VOCs) in soy, almond and oat beverages compared to bovine milk using proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS) as a rapid and noninvasive screening tool, complemented by gas chromatography-mass spectrometry (GC-MS) for compound identification. A total of 188 mass peaks were detected by PTR-ToF-MS, all showing significant differences from the blank, while GC-MS allowed the identification of 50 compounds, supporting the tentative identifications performed with PTR-MS analysis. In order to facilitate a comparison of different milks, after statistical analysis, these 188 mass peaks were further categorised into two groups: one consisting of VOCs with minimal variability across all samples and another comprising VOCs with significantly different abundances, distinctly characterising each beverage. Principal component analysis revealed a clear separation between bovine milk and PBMs, with almond beverages exhibiting the richest volatilome, while oat beverages displayed a more homogeneous volatile profile. PTR-ToF-MS demonstrated its ability to analyse volatile profiles rapidly, with excellent complementarity to GC-MS in terms of analytical versatility. The results provided a valuable basis for testing new experimental designs aimed to characterise and enhance flavour profiles in plant-based beverages, also after processing, in case of new product development that considers using these milks as raw material
Effects of dietary processed former foodstuffs on slaughter performance and meat quality in broilers
Get PDFThis study assessed the effects of incorporating commercially processed former foodstuffs (cFF) as substitutes for corn, soybean meal and soybean oil in broilers’ diet on slaughter performance, physicochemical properties and meat sensory attributes. Two hundred and one-day-old male chicks (ROSS-308) were divided into four dietary groups with increasing levels of cFF (0, 6.25%, 12.5% and 25%) named cFF0, cFF6.25, cFF12.5 and cFF25, respectively. On d 33, 25 chickens per dietary group were slaughtered for analyses. Carcase traits were similar across groups, except for a decrease in gizzard yield in cFF25 group (p = .008). Shear force, cooking loss and drip loss were unaffected by the diet. Meat pH decreased linearly in both breast and thigh muscles, and the thigh muscle yellowness index increased (p < .05). Breast crude protein (CP) decreased, while thigh CP and breast ether extract increased as the cFF inclusion level rose (p < .05). The fatty acid (FA) content of breast and thigh meat showed a linear increase in monounsaturated FA, with thigh meat also exhibiting a linear increase in saturated FA (SFA). Conversely, polyunsaturated FA (PUFA) and the PUFA to SFA ratio decreased with increasing cFF levels (p < .05). Lipid oxidation levels remained unchanged across groups. Sensory analysis revealed no differences in overall acceptability or liking among groups, although two sensory attributes (sour and hard) resulted as discriminating factors (p < .05). Overall, cFF inclusion did not affect meat quality, oxidative stability or consumer perception but altered the FA composition, suggesting the need of further investigation to assess the optimal inclusion leve
Global meta-analysis shows action is needed to halt genetic diversity loss
Get PDFMitigating loss of genetic diversity is a major global biodiversity challenge1,2,3,4. To meet recent international commitments to maintain genetic diversity within species5,6, we need to understand relationships between threats, conservation management and genetic diversity change. Here we conduct a global analysis of genetic diversity change via meta-analysis of all available temporal measures of genetic diversity from more than three decades of research. We show that within-population genetic diversity is being lost over timescales likely to have been impacted by human activities, and that some conservation actions may mitigate this loss. Our dataset includes 628 species (animals, plants, fungi and chromists) across all terrestrial and most marine realms on Earth. Threats impacted two-thirds of the populations that we analysed, and less than half of the populations analysed received conservation management. Genetic diversity loss occurs globally and is a realistic prediction for many species, especially birds and mammals, in the face of threats such as land use change, disease, abiotic natural phenomena and harvesting or harassment. Conservation strategies designed to improve environmental conditions, increase population growth rates and introduce new individuals (for example, restoring connectivity or performing translocations) may maintain or even increase genetic diversity. Our findings underscore the urgent need for active, genetically informed conservation interventions to halt genetic diversity los
Ancient duplication and functional differentiation of phytochelatin synthases is conserved in plant genomes
Get PDFDespite the paramount importance in metal(loid) detoxification by phytochelatin synthase (PCS) genes, no comprehensive analysis of their evolutionary patterns has been carried out in land plants in general and in crops in particular. A phylogenetic large-scale analysis of gene duplication in angiosperms was carried out followed by in vitro recombinant protein assays as well as complementation analysis (growth, thiol-peptides, elements) of Arabidopsis cad1-3 mutant with four representative PCS genes from two model crop species, Malus domestica and Medicago truncatula. We uncovered a so far undetected ancient tandem duplication (D duplication) spanning the whole core eudicotyledon radiation. Complementation with PCS genes from both D-subclades from M. domestica and M. truncatula displayed clear in vivo conservation of the differences between D1 and D2 paralogous proteins in plant growth, phytochelatin and glutathione pools, as well as element contents under heavy metal(loid) stress. In vitro recombinant PCS analysis identified analogous patterns of differentiation, showing a higher activity of D2 PCS genes, so far largely overlooked, compared to their paralogs from the D1 clade. This suggests that in many other crop species where the duplication is present, the D2 copy might play a significant role in metal(loid) detoxification. The retention of both PCS paralogs and of their functional features for such long divergence time suggests that PCS copy number could be constrained by functional specialization and/or gene dosage sensitivity. These results uncover the patterns of PCS evolution in plant genomes and of functional specialization of their paralogs in the genomes of two important model crops
Behaviour of brown bears under fluctuating resource availability
Get PDFMast seeding, the variable and intermittent production of seeds, has cascading effects on ecosystem functioning. This study explores its influence on the brown bear populations in the Italian Alps, focusing on beechnuts (Fagus sylvatica L.), the primary food source for bears in the region. Using historical data and field sampling, we estimated and mapped the annual seed biomass from 2007 to 2021 for the province of Trento. The energy content of beechnuts was assessed through high heating values, providing the caloric resources available. Data on beechnuts production, records of damages and GPS data from 16 Eurasian brown bears were integrated to perform a temporal and spatial analysis at home range and at landscape level. Standardised damages to beehives and livestock decreased during mast years, suggesting that bears met their trophic needs through natural food sources. In fact, bears used more agricultural areas and less beech forest during years of beech crop failure. At landscape level, agriculture and pasture areas close to beech forests and distant from cities showed a higher risk of damage, providing a tool to anticipate management actions. This work provides insights on the ecological dynamics and conservation implications of brown bears in the study area by mapping the spatial and temporal aspects of mast seeding and bear-related damage
Stable isotope analysis of alcoholic beverages: a review
Get PDFAbstract Alcoholic beverages represent a sector of significant economic and cultural importance but are also susceptible to fraud and adulteration, which can compromise their quality and authenticity. Isotopic analyses have become increasingly valuable tools for tracing the geographical origin and ensuring the quality control of products such as wine, beer, and distilled spirits. This literature review examines the main isotopic analysis techniques employed in this field, including Isotope Ratio Mass Spectrometry (IRMS) and Site-Specific Natural Isotope Fractionation by Nuclear Magnetic Resonance (SNIF-NMR), with a particular focus on the insights derived from the isotopic ratios of various elements, notably δ(2H), δ(13C), δ(18O), δ(15N) and δ(34S