Analysis of geochemical tracers in different systems soil-Citrus limon (L.) Osbeck

Today is increasing the attention of consumers for the origin of food and high reputation of products with a distinct geographical identity. Food traceability is an important issue in food safety and quality control, with impacts on food security, its quantity and overall availability. The knowledge of a chemistry relationship between the soil and the agricultural products is an important tool for the quality assessment of food. Citrus Limon is the most important fruit tree crop in the world and the detection of potential fraud could improve by using tools linking the chemistry composition of this production to its typical growing area. This study use rare earth elements (REEs) as geochemical tracers. The REEs are a set of 14 elements, from lanthanum to lutetium that can be divided in light rare earth elements (LREEs), from La to Gd and heavy rare earth elements (HREEs), from Tb to Lu. The REEs have recognized as very useful tracers due to their generally coherent and predictable behavior. The aim of the research is to observe whether the fruits of various cultivars of citrus cultivated on the same soil and their products (fruit and juice) reproduce the same distribution of REEs. Taking into account of our previous works carried out on grapevine – soil system [1, 2], we applied the same technique to evaluate and trace the REEs distribution in soil– Citrus Limon fruits system. Ten different varieties of Lemon fruits (Citrus limon Osbeck (L.)) were sampled. Lemon plant were grafted onto an unique rootstock (Citrus × aurantium L.), grown on volcanic soil in two experimental farms, located at the "Acireale" region (latitude 37 ° 37'23 N, longitude 15° 09'51.00 E and 205 m a.s.l., in Sicily, Italy) and “Portici” region (latitude 40 ° 81' 55 N, longitude 14° 34'75.00 E and 75 m a.s.l., in Campania, Italy). The varieties selected were: Akragas, Erice, Selinunte, Segesta, Continella, Femminello Siracusano, Femminello Dosaco, Kamarina, Sfusato, Ovale di Sorrento, Interdonato. A sample of 2 kg of fruit was collected at technological ripeness from each plant of three for every cultivar. As well as, three soil samples (about 2 kg) in the field corresponding to lemon sampling were collected and to reduce any surface contamination from a depth of 10–30 cm. The REEs amount, the HREEs/LREEs relations and their distribution in the fruit and citrus juice with respect to the own soil were determined and calculated. Results obtained were treated with statistical methods. The intriguing results obtained with a geochemical approach are the first on the soil–Citrus Limon fruits system

ATR-FTIR chemical screening for adulterants and sugar characterisation in honeys

The search for improvements in honey analysis is an important topic due to the relevance that adulterations and variations of sugar composition have in this food. Attenuated Total Reflectance Fourier Transform InfraRed spectroscopy (ATR-FTIR) is a reliable and fast analytical instrumentation for analysis of liquids, semi-solids and solids, which is currently used in food chemistry for qualitative and quantitative investigations. This work is aimed to build a fast analytical method, using ATR-FTIR and Partial Least Square (PLS) chemometric tool, to quantitative determination of glucose, fructose and sucrose present in honeys. We analyzed 25 honeys from Trentino and Sicily and a significant spectral range from the whole ATR-FTIR spectra were selected. Then a PLS multivariate calibration model was built by using mixtures of glucose, fructose and sucrose at various concentration. Samples for cross-validation were selected, thereby allowing quantitative evaluation of glucose, fructose and sucrose in all samples. Furthermore, a representative number of honeys were mixed with common adulterant syrups to simulate adulteration procedures and to verify the reliability of the ATR-FTIR technique in recognizing them. Preliminary results revealed not only the quantitative reliability of ATR-FTIR spectroscopy in the evaluation of sugars in honeys, but also its ability in recognizing honey adulteration

Preliminary studies of geochemical tools to traceability of Sicilian honey

Today is increasing the attention of consumers for the origin of food and high reputation of products with a distinct geographical identity. Food traceability is an important issue in food safety and quality control, with impacts on food security, its quantity and overall availability. Furthermore, the possibility of tracing the origin of foodstuff is assuming an increasingly important role at the legislative level, as a tool that may allow to prove on product authenticity and to control adulteration So, establish systems to trace food or feed products through specified stages of production, processing and distribution play a key role also to ensure food safety. For these reason, in the last years, a various of analytical techniques have been tested to found ways to establish the geographical origin of different kinds of food and many works reported that the combination of different analytical methods associated a multifactorial analysis of the data seems to be the most promising system to establish univocal traceability systems. Despite, the honey is a well appreciated natural product in the world and the detection of potential fraud could be favored through tools linking the chemistry composition of this production to producing area. A relatively small number of investigations regarding traceability of honey can be found in the scientific literature. Therefore, in these contest the development of fingerprinting techniques based on the determination of the specific markers of provenance analyzed whit chemometric approach represents an interesting area of research. Recent works have been demonstrated the potentiality of the study of the distribution patterns of rare earth as a promising analytical method for traceability of food products due coherent and predictable chemical behaviour of these compounds. Also, have been demonstrated that their distribution in soil keeps unaltered in plants growing on that soil and eventually in agricultural products obtained from those plants and through the normalization of the REEs distribution, it is possible to appreciate their relative enrichments in soil-plant- agro food products The aim of the research is to observe if the REEs normalizated pattern of honey is kept unaltered respect the soils of production to establish a correlation between geographic area and honey product. In this first study the REE approach, give very intriguing results in the geographical traceability of honey samples. The results have been supported by statistical treatment. A larger study is in progress to optimize the analytical methodology and to extend the research to a major number of sample for a better geographical characterization

Water formation at low temperatures by surface O2 hydrogenation I: characterization of ice penetration

Water is the main component of interstellar ice mantles, is abundant in the solar system and is a crucial ingredient for life. The formation of this molecule in the interstellar medium cannot be explained by gas-phase chemistry only and its surface hydrogenation formation routes at low temperatures (O, O2, O3 channels) are still unclear and most likely incomplete. In a previous paper we discussed an unexpected zeroth-order H2O production behavior in O2 ice hydrogenation experiments compared to the first-order H2CO and CH3OH production behavior found in former studies on hydrogenation of CO ice. In this paper we experimentally investigate in detail how the structure of O2 ice leads to this rare behavior in reaction order and production yield. In our experiments H atoms are added to a thick O2 ice under fully controlled conditions, while the changes are followed by means of reflection absorption infrared spectroscopy (RAIRS). The H-atom penetration mechanism is systematically studied by varying the temperature, thickness and structure of the O2 ice. We conclude that the competition between reaction and diffusion of the H atoms into the O2 ice explains the unexpected H2O and H2O2 formation behavior. In addition, we show that the proposed O2 hydrogenation scheme is incomplete, suggesting that additional surface reactions should be considered. Indeed, the detection of newly formed O3 in the ice upon H-atom exposure proves that the O2 channel is not an isolated route. Furthermore, the addition of H2 molecules is found not to have a measurable effect on the O2 reaction channel.Comment: 1 page, 1 figur

New chemiometric technique applied to traceability of Sicilian honey of Sulla (Hedysarum coronarium L.)

The consumers have an increasing interest about food traceability with respect to safety, quality and typicality issues. Food traceability is an important issue in food safety and quality control, with impacts on food security, its quantity and overall availability. Furthermore, the possibility of tracing the origin of foodstuff is assuming an increasingly important role at the legislative level, as a tool that may allow to prove on product authenticity and to control adulteration. So, establish systems to trace food products through specified stages of production, processing and distribution play a key role also to ensure food safety. In the last years, several of analytical techniques have been tested to found ways to establish the geographical origin of different kinds of food and many works reported that the combination of different analytical methods associated a multifactorial analysis of the data seems to be the most promising system to establish univocal traceability systems. The honey is a natural food well appreciated in the world and the detection of potential fraud could be favored through tools linking the chemistry composition of this production to producing area. A small number of investigations regarding traceability of honey can be found in the scientific literature. Therefore, in these contest the development of fingerprinting techniques based on the determination of the specific markers of provenance analyzed whit chemometric approach represents an interesting area of research. Recent works have been demonstrated the potentiality of the study of the distribution patterns of rare earth as a promising analytical method for traceability of food products due coherent and predictable chemical behavior of these compounds. Also, have been demonstrated that their distribution in soil keeps unaltered in plants growing on that soil and eventually in agricultural products obtained from those plants and through the normalization of the REEs distribution, it is possible to appreciate their relative enrichments in soil-plant- agro food products The aim of the research was to observe if the REEs normalizated pattern of honey of Sulla (Hedysarum coronarium L.) was kept unaltered respect the soils of production to establish a correlation between geographic area and honey product. For this study, different production areas of Sulla in Sicily were considered. The production fields explored by the bees within 2 km of the hives were taken into consideration, the soil and the flowering plants were sampled. Flowers and leaves were analyzed from the plant. In the hive, pollen and honey were taken in three different days during the flowering period of the Sulla. Of same areas were sampled to the same methods in different periods where other monofloral honeys were product, these samples were used for a control. In this study the REE approach, give very intriguing results in the geographical traceability of honey samples and are the first. The results have been supported by statistical treatment

H-atom addition and abstraction reactions in mixed CO, H2CO and CH3OH ices: an extended view on complex organic molecule formation

Complex organic molecules (COMs) have been observed not only in the hot cores surrounding low- and high- mass protostars, but also in cold dark clouds. Therefore, it is interesting to understand how such species can be formed without the presence of embedded energy sources. We present new laboratory experiments on the low-temperature solid state formation of three complex molecules: methyl formate (HC(O)OCH3), glycolaldehyde (HC(O)CH2OH) and ethylene glycol (H2C(OH)CH2OH), through recombination of free radicals formed via H-atom addition and abstraction reactions at different stages in the CO-H2CO-CH3OH hydrogenation network at 15 K. The experiments extend previous CO hydrogenation studies and aim at resembling the physical&chemical conditions typical of the CO freeze-out stage in dark molecular clouds, when H2CO and CH3OH form by recombination of accreting CO molecules and H-atoms on ice grains. We confirm that H2CO, once formed through CO hydrogenation, not only yields CH3OH through ongoing H-atom addition reactions, but is also subject to H-atom-induced abstraction reactions, yielding CO again. In a similar way, H2CO is also formed in abstraction reactions involving CH3OH. The dominant methanol H-atom abstraction product is expected to be CH2OH, while H-atom additions to H2CO should at least partially proceed through CH3O intermediate radicals. The occurrence of H-atom abstraction reactions in ice mantles leads to more reactive intermediates (HCO, CH3O and CH2OH) than previously thought, when assuming sequential H-atom addition reactions only. This enhances the probability to form COMs through radical-radical recombination without the need of UV photolysis or cosmic rays as external triggers.Comment: 20 pages, 8 figure

From wastes to resources: citrus hydrolatesas natural biostimulants of soil microorganisms

The hydrolates result from the industrial extraction process of the essential oils through cold pressing of the citrus peels. Today, they are considered a waste to be disposed of. However, due to the presence of water soluble compounds (sugars, polyphenols, acids), hydrolates could be reused instead of being, due to the high economic burden, a problem in the disposal of the same, charged to the company.The aim of this work was to evaluate the effects of citrus hydrolate when directly applied as irrigation water on soil microbial biomass, activity and structure community. The soil used for the experiment was collected from the topsoil (0-10 cm) of a citrus orchard, air-dried and sieved at 2 mm. Then, 450 g of soil were placed in 1L plastic bottles and moistened up to 50% of the water holding capacity (WHC) by applying hydrolates and/or water. The tested hydrolates were obtained from three citrus species: Citrus Sinensis, Citrus Limon and Citrus Reticulata. The hydrolates were applied at three different doses to reach 1/3, 2/3 and 3/3 of the 50% of soil WHC. Respectively, 35, 70 and 105 mL of hydrolate were added to 450 g of air-dried soil. Distilled water was added when necessary to complement the 50% of WHC. Control soil was moistened up to 50% of its WHC with distilled water only. At the same time, 20 g of soil per each treatment were similarly incubated in 200 mL jars, sealed with rubber stopper holding silicon septa to monitor the emission of CO2. Four replicates per treatment were run. Soil samples were incubated in the dark at constant temperature (23.0 ± 0.5°C) and their humidity weekly adjusted up to 50% of WHC by adding distilled water. Microbial biomass C was determined according to the fumigation-extraction method after 1, 4, 8, 12 and 16 weeks of incubation. At the same time, soil fatty acid methyl esters were determined and used as indicators of the main microbial groups. The CO2 accumulated in the headspace of the jars was measured at days 2, 5, 7 during the first week, then weekly for the following month and finally bi-weekly until day 112. The preliminary results provided evidence that the three hydrolates, at different extent, stimulated the activity of soil microorganisms and affected soil microbial biomass and community structure

EFFECTS OF CITRUS ESSENTIAL OILS ON THE MICROBIOLOGICAL SAFETY OF PRIMO SALE CHEESE

In the last years, the consumers demanding foods with no chemical preservatives for food conservation, determined an interest by the food industries for the use of natural biopreservatives. Several essential oils from various plants and fruits have been characterized for their antibacterial activities in order to select new biopreservatives. The aim of this work was to evaluate the organoleptic effect of citrus essential oils to be applied in the processing of sheeps’ milk “Primo Sale” cheese and the inhibitory effect on the main bacterial pathogens of dairy interest. In order to better evaluate the antibacterial effect, the first approach was based on pasteurized milk, in view of the future application in raw milk cheese production. Three industrial citrus essential oils (EOs) extracted by cold pressing of the citrus peels were tested: Orange [Citrus sinensis (L.) Osbeck] Lemon [Citrus limon (L.) Osbeck] and Tangerine [Citrus reticulata Blanco]; sheep bulk milk was pasteurized for 30 min at 60°C. Each EO was tested at two different concentrations 100 and 200 µl/l of milk. For each dose two cheese makings were made: one production was not added with pathogenic bacteria to evaluate the organoleptic characteristics, while the second production was added with 30 CFU/mL of Listeria monocytogenes 24B0 and Salmonella typhimurium 50431 and 103 CFU/mL of Escherichia coli C45/1245 and Staphylococcus aureus PSS52. All cheeses were obtained by coagulation with 0.3 mL/L of microbial rennet (Fromase® 220 TL, DSM Bright Science Brighter Living, Heerlen, UK) and acidification by means of the starter culture Lactococcus lactis CAG4 and CAG37 10 mL/L to reach a final concentration of 106 CFU/ml in milk. Four cheese makings without EOs were used as control trials and prepared as follows: only rennet; rennet plus pathogenic bacteria; rennet plus starters; and rennet plus pathogenic and starters. Cheese samples were homogenised with a stomacher (BagMixer® 400, Interscience, Saint Nom, France). Microbial suspensions were plated and incubated as follows: Lactic acid bacteria cocci on M17 agar, incubated anaerobically at 30°C for 48 h; L. monocytogenes on Listeria selective agar base incubated at 37°C for 48 h; Escherichia coli and S. typhimurium were both detected on Hektoen enteric agar incubated at 37°C for 24 h; St. aureus on Baird Parker and incubated at 37°C for 48 h. Although in vitro tests showed a certain inhibition against especially, the Gram positive bacteria, but also towards Salmonella spp. none of the two Gram negative pathogens was inhibited in cheeses. Optimal results were registered against L. monocytogenes which was inhibited of almost 3 Log cycles by all EOs at both concentrations tested. St. aureus was not inhibited by orange EO, while 1-2 Log cycles lower than control (only pathogens) were found in EO cheeses. The inhibitory effect could also be due to the competitions for nutrients due to the most rapid growth of Lc. lactis. However, the difference registered among orange and the other two citrus EO trials highlighted the in vivo antibacterial activity of lemon and mandarin EOs. Sensory tests are being prepared to evaluate the appreciation by judges

Monitoring of the effects of added carbon by citrus hydrolates waste in a soil.

The hydrolates are the waste to be disposed of are a product of the industrial extraction process of the essential oils through cold pressing of the citrus peels. However, due to the presence of water soluble compounds (sugars, polyphenols, acids), hydrolates could be reused instead of being, due to the high economic burden, a problem in the disposal of the same, charged to the company. The aim of this work was to evaluate the effects of citrus hydrolate when directly applied as irrigation water on soil. Was monitored soil chemical and biochemical property, in particularly effect of the high carbon addition on microbial biomass, activity and structure community and effect on carbon soil stock. The soil used for the experiment was collected from the topsoil (0-10 cm) of a citrus lemon orchard, air-dried and sieved at 2 mm. Then, 450 g of soil were placed in 1L jar and moistened up to 50% of the water holding capacity (WHC) by applying hydrolates and/or water. The tested hydrolates were obtained from three citrus species: Citrus Sinensis, Citrus Limon and Citrus Reticulata. The hydrolates were applied at three different doses to reach 1/3, 2/3 and 3/3 of the 50% of soil WHC. Respectively, 35, 70 and 105 ml of hydrolate were added to 450 g of air-dried soil. Distilled water was added when necessary to complement the 50% of WHC. Control soil was moistened up to 50% of its WHC with distilled water only. At the same time, 20 g of soil per each treatment were similarly incubated in 200 mL jars, sealed with rubber stopper holding silicon septa to monitor the emission of CO2. Four replicates per treatment were run. Soil samples were incubated in the dark at constant temperature (23.0 ± 0.5°C) and their humidity weekly adjusted up to 50% of WHC by adding distilled water. Microbial biomass C was determined according to the fumigation-extraction method after 1, 4 and 8, weeks of incubation. At the same time, soil fatty acid methyl esters (FAMEs) were determined and used as indicators of the main microbial groups. The CO2 accumulated in the headspace of the jars was measured at days 2, 5, 7 during the first week, then weekly for the following month and finally bi-weekly until day 60. This preliminary study for the possible use of citrus hydrolates as amenders and biostimulants for soil microorganisms showed that they might constitute readily available sources of carbon for microorganisms but at different extent, depending on the citrus species

Detection of the hydroperoxyl radical HO2 toward \rho Oph A: Additional constraints on the water chemical network

Context: Hydrogen peroxide (HOOH) was recently detected toward \rho Oph A. Subsequent astrochemical modeling that included reactions in the gas phase and on the surface of dust grains was able to explain the observed abundance, and highlighted the importance of grain chemistry in the formation of HOOH as an intermediate product in water formation. This study also predicted that the hydroperoxyl radical HO2, the precursor of HOOH, should be detectable. Aims: We aim at detecting the hydroperoxyl radical HO2 in \rho Oph A. Methods: We used the IRAM 30m and the APEX telescopes to target the brightest HO2 lines at about 130 and 260 GHz. Results: We detect five lines of HO2 (comprising seven individual molecular transitions). The fractional abundance of HO2 is found to be about 1e-10, a value similar to the abundance of HOOH. This observational result is consistent with the prediction of the above mentioned astrochemical model, and thereby validates our current understanding of the water formation on dust grains. Conclusions: This detection, anticipated by a sophisticated gas-grain chemical model, demonstrates that models of grain chemistry have improved tremendously and that grain surface reactions now form a crucial part of the overall astrochemical network.Comment: 5 pages, 4 figures, accepted for publication as a Letter to the Editor in Astronomy and Astrophysic