Re-determination of R(13C/12C) for Vienna Peedee belemnite (VPDB).

RATIONALE: The isotope ratio for the internationally agreed but virtual zero-point of the carbon isotope-delta scale, Vienna Peedee belemnite (VPDB), plays a critical role in linking carbon isotope delta values to the SI. It is also a quantity used for various data processing procedures including '17O correction', clumped isotope analysis and conversion of carbon isotope delta values into other expressions of isotopic composition. A value for RVPDB(13C/12C) with small uncertainty is therefore desirable to facilitate these procedures. METHODS: The value of RVPDB(13C/12C) was determined by errors-in-variables regression of isotope delta values traceable to VPDB measured by isotope ratio mass spectrometry against isotope ratios traceable to the SI by use of gravimetric mixtures of 12C- and 13C-enriched d-glucose measured by multicollector inductively coupled plasma mass spectrometry. RESULTS: A value of RVPDB(13C/12C) = 0.0111105 ± 0.0000042 (expanded uncertainty, k = 2) was obtained. CONCLUSIONS: The new value for RVPDB(13C/12C) agrees very well with the consensus values calculated from previous measurement results proposed by Kaiser and by ourselves, as well as recent determinations independent of mass spectrometry. The expanded uncertainty of 0.4‰ when expressed as an isotope delta value is a tenfold improvement over the previous best measurement of the isotopic composition of carbon.

Is Sustainable Consumption a Sufficient Motivator for Consumers to Adopt Meat Alternatives? A Consumer Perspective on Plant-Based, Cell-Culture-Derived, and Insect-Based Alternatives.

This study investigates consumer preference and acceptance of three meat alternatives-plant-based, lab-grown, and insect-based-as sustainable choices to meet the demands of a growing population and evolving food systems. Insights were gathered from European consumers regarding their perceptions and consumption patterns using a mixed-methods approach. The approach employed a questionnaire followed by focus group discussions conducted in Slovenia and the UK to understand the motivations and barriers behind their responses. The UK and Slovenia were chosen as they provided the highest response rates to the questionnaire and they have differing legislation. The results show that plant-based alternatives are the most familiar and accepted option, while lab-grown meat and insect-based products are less familiar and have lower acceptance rates. Moreover, they show that although sustainability factors are important to consumers, they are not their only concern; health and nutrition are the primary motivators for choosing meat alternatives. These are followed closely by sensory appeal, pricing, and a preference for natural, minimally processed options. Based on insights from the focus groups, strategies to overcome the barriers to the acceptance of meat alternatives should include targeted product categorisation and placement, educational campaigns, effective use of media, and greater transparency in product information.

Optimization and validation of an HS-SPME/GC-MS method for determining volatile organic compounds in dry-cured ham.

The formation of volatile organic compounds (VOCs) in dry-cured ham is a result of different biochemical and enzymatic processes. Moreover, accurately quantifying these VOCs is challenging since ham is a complex matrix, which contains compounds from various chemical families and a wide range of volatilities of different molecular masses. In this study, we systematically optimized and validated an analytical method for quantifying VOCs in dry-cured ham using headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Optimal SPME conditions were determined through both an experimental procedure (one-factor-at-a-time) and response surface methodology (RSM), revealing that a 60-min equilibration at 70°C, a 60-min extraction at the same temperature, and a 4-min desorption time at 250°C provided the most favorable results. To enhance quantitation, twelve multiple internal standards (ISTDs) were employed to address and improve the quantitation of the 12 VOCs. Method validation covered aspects of linearity, limits of detection (LOD: 0.03-1.13 mg kg-1), limits of quantitation (LOQ: 0.09-3.41 mg kg-1), and working ranges (0.01-19.1 mg kg-1). The practical application of this optimized method was demonstrated by analyzing dry-cured ham samples (n = 4), sourced from the Slovenian market. The initial statistical evaluation indicates that different types of dry-cured hams can be differentiated (with an 83.1% of accuracy) according to their aromatic profile. However, a larger sample size would be required to provide a more comprehensive assessment.

From language models to large-scale food and biomedical knowledge graphs.

Knowledge about the interactions between dietary and biomedical factors is scattered throughout uncountable research articles in an unstructured form (e.g., text, images, etc.) and requires automatic structuring so that it can be provided to medical professionals in a suitable format. Various biomedical knowledge graphs exist, however, they require further extension with relations between food and biomedical entities. In this study, we evaluate the performance of three state-of-the-art relation-mining pipelines (FooDis, FoodChem and ChemDis) which extract relations between food, chemical and disease entities from textual data. We perform two case studies, where relations were automatically extracted by the pipelines and validated by domain experts. The results show that the pipelines can extract relations with an average precision around 70%, making new discoveries available to domain experts with reduced human effort, since the domain experts should only evaluate the results, instead of finding, and reading all new scientific papers.

Contaminant uptake in wastewater irrigated tomatoes.

As population growth and climate change add to the problem of water scarcity in many regions, the argument for using treated wastewater for irrigation is becoming increasingly compelling, which makes understanding the risks associated with the uptake of harmful chemicals by crops crucial. In this study, the uptake of 14 chemicals of emerging concern (CECs) and 27 potentially toxic elements (PTEs) was studied in tomatoes grown in soil-less (hydroponically) and soil (lysimeters) media irrigated with potable and treated wastewater using LC-MS/MS and ICP-MS. Bisphenol S, 2,4 bisphenol F, and naproxen were detected in fruits irrigated with spiked potable water and wastewater under both conditions, with BPS having the highest concentration (0.034-0.134 µg kg-1 f. w.). The levels of all three compounds were statistically more significant in tomatoes grown hydroponically (

Determining the Authenticity of Spirulina Dietary Supplements Based on Stable Isotope and Elemental Composition.

While the demand for Spirulina dietary supplements continues to grow, product inspection in terms of authenticity and safety remains limited. This study used the stable isotope ratios of light elements (C, N, S, H, and O) and the elemental composition to characterize Spirulina dietary supplements available on the Slovenian market. Forty-six samples were labelled as originating from the EU (1), non-EU (6), Hawaii (2), Italy (2), Japan (1), Portugal (2), Taiwan (3), India (4), and China (16), and nine products were without a declared origin. Stable isotope ratio median values were -23.9‱ (-26.0 to -21.8‱) for δ13C, 4.80‱ (1.30-8.02‱) for δ15N, 11.0‱ (6.79-12.7‱) for δ34S, -173‱ (- 190 to -158‱) for δ2H, and 17.2‱ (15.8-18.8‱) for δ18O. Multivariate statistical analyses achieved a reliable differentiation of Hawaiian, Italian, and Portuguese (100%) samples and a good separation of Chinese samples, while the separation of Indian and Taiwanese samples was less successful, but still notable. The study showed that differences in isotopic and elemental composition are indicative of sample origins, cultivation and processing methods, and environmental conditions such that, when combined, they provide a promising tool for determining the authenticity of Spirulina products.

Reply to Horacek, M.; Cannavan, A. Comment on "Sinkovic et al. Isotope Fingerprints of Common and Tartary Buckwheat Grains and Milling Fractions: A Preliminary Study. Foods 2022, 11, 1414".

We thank Dr. Horacek and Dr. Cannavan for their interest [...].

Characterization of Botanical Origin of Italian Honey by Carbohydrate Composition and Volatile Organic Compounds (VOCs).

Honey is a natural sweetener constituted by numerous macro- and micronutrients. Carbohydrates are the most representative, with glucose and fructose being the most abundant. Minor honey components like volatile organic compounds (VOCs), minerals, vitamins, amino acids are able to confer honey-specific properties and are useful to characterize and differentiate between honey varieties according to the botanical origin. The present work describes the chemical characterization of honeys of different botanical origin (multifloral, acacia, apple-dandelion, rhododendron, honeydew, and chestnut) produced and collected by beekeepers in the Trentino Alto-Adige region (Italy). Melissopalynological analysis was conducted to verify the botanical origin of samples and determine the frequency of different pollen families. The carbohydrate composition (fourteen sugars) and the profile of VOCs were evaluated permitting to investigate the relationship between pollen composition and the chemical profile of honey. Statistical analysis, particularly partial least squares discriminant analysis (PLS-DA), demonstrates the importance of classifying honey botanical origin on the basis of effective pollen composition, which directly influences honey's biochemistry, in order to correctly define properties and value of honeys.

Isotope Fingerprints of Common and Tartary Buckwheat Grains and Milling Fractions: A Preliminary Study.

The grains and milling fractions of common buckwheat (Fagopyrum esculentum Moench) and Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) are widely used for both industrial and small-scale food and non-food products. This paper represents a preliminary study of the isotopic signature (δ13C, δ15N, and δ34S) to differentiate between buckwheat species (common vs. Tartary), organic and conventional cultivation farming, and different buckwheat fractions (light flour, semolina, and hulls) obtained by a traditional cereal stone-mill. Stable isotope ratios were analyzed using an elemental analyzer coupled to an isotope ratio mass spectrometer (EA/IRMS). The results indicated that δ13C, δ15N, and δ34S values could be used to verify the origin and production practices of buckwheat and even its products.

Nutritional Quality and Safety of the Spirulina Dietary Supplements Sold on the Slovenian Market.

The microalgae Spirulina may be a popular dietary supplement rich in essential nutrients and vitamins, but oversight of the supplement industry, in general, remains limited, and increasing incidents of adulteration, misbranding, and undeclared ingredients together with misleading claims create potential risks. In response, this study characterized the elemental, amino acid and fatty acid content of commercially available Spirulina supplements in Slovenia using EDXRF, ICP-MS and GC-MS and compared the results with their nutritional declaration. The gathered data confirm that Spirulina supplements are a good source of calcium (0.15 to 29.5% of RDA), phosphorous (3.36-26.7% of RDA), potassium (0.5 to 7.69% of RDA) and selenium (0.01 to 38.6% of RDA) when consumed within recommended amounts. However, although iron contents were relatively high (7.64 to 316% of RDA), the actual bioavailability of iron was much lower since it was mainly present as the ferric cation. This study also confirms that pure Spirulina supplements are a good source of essential and non-essential amino acids, and ω-6 but not ω-3 polyunsaturated fatty acids. The presence of additives resulted in significant variation in nutrient content and, in some instances, lower product quality. Moreover, a high proportion (86.7%) of inappropriate declarations regarding the elemental content was observed. Overall, the study conclusions underline the need for a stricter control system for Spirulina-based supplements.

Fermented Biomass of Arthrospira platensis as a Potential Food Ingredient.

Lactic acid fermentation (LAF) is known to improve nutritional properties and functionality and to extend the shelf life of foods. We studied the LAF of Arthrospira platensis as the sole substrate using Lactobacillus plantarum as the starter culture. Fermented (FB) and non-fermented broth (NFB) were analysed by means of pH, lactic acid bacteria (LAB) count, lactic acid concentration, microbiological safety, and nutritional composition. Additionally, water and ethanol extracts were prepared on which total phenolic content, DPPH radical scavenging activity, and cellular antioxidant activity were determined. The maximum increase in LAB count and lactic acid concentration and drop in pH was observed in the first 24 h of fermentation. Total phenolic content and DPPH radical scavinging activity of ethanol extracts increased after fermentation compared with NFB. Ethanol extracts of FB have been shown as a potential source of antioxidants, which efficiently lowered oxidation level in the cells of yeast Saccharomyces cerevisiae, as well as the oxidative damage of lipids. Additionally, the level of non-protein nitrogen increased, indicating higher protein bioavailability, and fat content decreased in comparison with NFB. No presence of pathogenic bacteria and low pH indicate enhancement of FB microbiological stability. Therefore, inclusion of fermented A. platensis into food products could lead to added-value foods based on microalgae.

Reply to Horacek, M. The Need to Consider Geochemistry When Interpreting Sr-Isotopes. Comment on "Gregorcic et al. The Provenance of Slovenian Milk Using 87Sr/86Sr Isotope Ratios. Foods 2021, 10, 1729".

We appreciate Dr Horacek's interest in our paper and his feedback [...].

Geographical identification of strawberries based on stable isotope ratio and multi-elemental analysis coupled with multivariate statistical analysis: A Slovenian case study.

The geographical classification and authentication of strawberries were attempted using discriminant and class-modelling methods applied to stable isotopes of light elements and elemental composition. The work involved creating a database of 92 authentic Slovenian strawberry samples and 32 imported samples. All samples were harvested between 2018 and 2020. A good geographical classification of Slovenian and non-Slovenian strawberries was obtained despite different production years using discriminant approaches. However, for verifying compliance with a given specification (geographical indications), a class-modelling approach was used to build an unbiased verification model. Class models generated by data-driven soft independent modelling of class analogy (DD-SIMCA) had high sensitivity (96% to 97%) and good specificity (81% to 91%) on a yearly basis, while a more generalised model combining total yearly data gave a lower specificity (63%). Of the 33 commercially available samples (test samples) with declared Slovenian origin, 39% were from outside of Slovenia.

The Effect of Cultivation Practices on Agronomic Performance, Elemental Composition and Isotopic Signature of Spring Oat (Avena sativa L.).

The present study investigated the effects of cultivation practices on grain (oats) yield and yield components, such as straw yield, harvest index, thousand kernel weight, and plant lodging. In addition, multi-element composition and isotopic signature (δ13C, δ15N) of the oat grains were studied. The spring oat cultivar 'Noni' was grown in a long-term field experiment during 2015-2020, using three management practices: control without organic amendment, incorporation of manure every third year and incorporation of crop residues/cover crop in the rotation. Synthetic nitrogen (N) (0, 55, 110 and 165 kg/ha) was applied during oat development in each system. Multi-element analysis of mature grains from two consecutive years (2016 and 2017) was performed using EDXRF spectroscopy, while stable isotope ratios of carbon (C) and nitrogen (N) were obtained using an elemental analyzer coupled to an isotope ratio mass spectrometer (EA/IRMS). The results show how cultivation practices affect yield components and isotopic and elemental signatures. Increasing the N rate improved both the oat grain and straw yields and increased susceptibility to lodging. The results show how the elemental content (Si, Ca, Zn, Fe, Ti, Br and Rb) in the oat grains were influenced by intensification, and a noticeable decrease in elemental content at higher N rates was the result of a dilution effect of increased dry matter production. The mean δ15N values in oat grains ranged from 2.5‱ to 6.4‱ and decreased with increasing N rate, while δ13C values ranged from -29.9‱ to -28.9‱. Based on the δ15N values, it was possible to detect the addition of synthetic N above an N rate of 55 kg/ha, although it was impossible to differentiate between different management practices using stable isotopes.

Dryland irrigation increases accumulation rates of pedogenic carbonate and releases soil abiotic CO2.

Agricultural fields in drylands are challenged globally by limited freshwater resources for irrigation and also by elevated soil salinity and sodicity. It is well known that pedogenic carbonate is less soluble than evaporate salts and commonly forms in natural drylands. However, few studies have evaluated how irrigation loads dissolved calcium and bicarbonate to agricultural fields, accelerating formation rates of secondary calcite and simultaneously releasing abiotic CO2 to the atmosphere. This study reports one of the first geochemical and isotopic studies of such "anthropogenic" pedogenic carbonates and CO2 from irrigated drylands of southwestern United States. A pecan orchard and an alfalfa field, where flood-irrigation using the Rio Grande river is a common practice, were compared to a nearby natural dryland site. Strontium and carbon isotope ratios show that bulk pedogenic carbonates in irrigated soils at the pecan orchard primarily formed due to flood-irrigation, and that approximately 20-50% of soil CO2 in these irrigated soils is calcite-derived abiotic CO2 instead of soil-respired or atmospheric origins. Multiple variables that control the salt buildup in this region are identified and impact the crop production and soil sustainability regionally and globally. Irrigation intensity and water chemistry (irrigation water quantity and quality) dictate salt loading, and soil texture governs water infiltration and salt leaching. In the study area, agricultural soils have accumulated up to 10 wt% of calcite after just about 100 years of cultivation. These rates will likely increase in the future due to the combined effects of climate variability (reduced rainfall and more intense evaporation), use of more brackish groundwater for irrigation, and reduced porosity in soils. The enhanced accumulation rates of pedogenic carbonate are accompanied by release of large amounts of abiotic CO2 from irrigated drylands to atmosphere. Extensive field studies and modelling approaches are needed to further quantify these effluxes at local, regional and global scales.

"Kisanje" severnega Jadrana.

The present knowledge of the carbonate system in the northern Adriatic is described in this short overview. Its buffer capacity is rather high, due to riverine input of carbonates dissolved from Alpine and Karstic watersheds, and the waters should have a higher resilience to acidification. In the shallow eutrophic areas, the combined effect of rising atmospheric CO2, warming and river-induced anthropogenic CO2 with the associated decrease in buffer capacity could act to acidification process. Significant effect on calcifying organisms is expected in the future.

Extremophilic Microorganisms in Central Europe.

Extremophiles inhabit a wide variety of environments. Here we focus on extremophiles in moderate climates in central Europe, and particularly in Slovenia. Although multiple types of stress often occur in the same habitat, extremophiles are generally combined into groups according to the main stressor to which they are adapted. Several types of extremophiles, e.g., oligotrophs, are well represented and diverse in subsurface environments and karst regions. Psychrophiles thrive in ice caves and depressions with eternal snow and ice, with several globally distributed snow algae and psychrophilic bacteria that have been discovered in alpine glaciers. However, this area requires further research. Halophiles thrive in salterns while thermophiles inhabit thermal springs, although there is little data on such microorganisms in central Europe, despite many taxa being found globally. This review also includes the potential use of extremophiles in biotechnology and bioremediation applications.

Insight into the Antioxidant Effect of Fermented and Non-Fermented Spirulina Water and Ethanol Extracts at the Proteome Level Using a Yeast Cell Model.

Spirulina is rich in various antioxidants and nutraceuticals and it has proven to be effective in the treatment of various pathological conditions. This study explores the antioxidant effect of fermented and non-fermented Spirulina extracts on the proteome level using the yeast Saccharomyces cerevisiae as a model organism. Yeast cells were treated with fermented Spirulina water extract (SV), non-fermented Spirulina water extract (NFV), fermented Spirulina ethanol extract (SE), and non-fermented Spirulina ethanol extract (NFE). Cell lysates were prepared, and label-free quantitative proteome analysis was performed. In SV, when compared to NFV samples, the levels of most differentially expressed proteins were upregulated. Alternatively, SE compared to NFE samples showed a significant downregulation for the majority of the analyzed proteins involved in different cellular processes. Additionally, a higher downregulation of stress response related proteins was observed in SE compared to NFE samples, while their abundance in SV samples increased compared to NFV. This study provided a global view, on a proteome level, of how cells cope with exogenous antioxidants and remodel their cellular processes to maintain metabolic and redox balance. Furthermore, it combined for the first time the analysis of different extract effect, including the contribution of lactic acid fermentation to the cell activity.

Construction of IsoVoc Database for the Authentication of Natural Flavours.

Flavour is an important quality trait of food and beverages. As the demand for natural aromas increases and the cost of raw materials go up, so does the potential for economically motivated adulteration. In this study, gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) analysis of volatile fruit compounds, sampled using headspace-solid phase microextraction (HS-SPME), is used as a tool to differentiate between synthetic and naturally produced volatile aroma compounds (VOCs). The result is an extensive stable isotope database (IsoVoc-Isotope Volatile organic compounds) consisting of 39 authentic flavour compounds with well-defined origin: apple (148), strawberry (33), raspberry (12), pear (9), blueberry (7), and sour cherry (4) samples. Synthetically derived VOCs (48) were also characterised. Comparing isotope ratios of volatile compounds between distillates and fresh apples and strawberries proved the suitability of using fresh samples to create a database covering the natural variability in δ13C values and range of VOCs. In total, 25 aroma compounds were identified and used to test 33 flavoured commercial products to evaluate the usefulness of the IsoVoc database for fruit flavour authenticity studies. The results revealed the possible falsification for several fruit aroma compounds.

The Provenance of Slovenian Milk Using 87Sr/86Sr Isotope Ratios.

This work presents the first use of Sr isotope ratios for determining the provenance of bovine milk from different regions of Slovenia. The analytical protocol for the determination of 87Sr/86Sr isotope ratio was optimised and applied to authentic milk samples. Considerable variability of 87Sr/86Sr ratios found in Slovenian milk reflects the substantial heterogeneity of the geological background of its origin. The results, although promising, cannot discount possible inter-annual or annual variation of the Sr isotopic composition of milk. The 87Sr/86Sr ratios of groundwater and surface waters are in good correlation with milk, indicating that the Sr isotopic fingerprint in milk is reflective of cow drinking water. The 87Sr/86Sr ratio has the potential to distinguish between different milk production areas as long as these areas are characterised by geo-lithology. Discriminant analysis (DA) incorporating the elemental composition and stable isotopes of light elements showed that 87Sr/86Sr ratio together with δ13Ccas and δ15Ncas values have the main discrimination power to distinguish the Quaternary group (group 6) from the others. Group 1 (Cretaceous: Carbonate Rocks and Flysch) is associated with Br content, 1/Sr and δ18Ow values. The overall prediction ability was found to be 63.5%. Pairwise comparisons using OPLS-DA confirmed that diet and geologic parameters are important for the separation.