pinecone/core-2020-05-10-deduplication huggingface dataset:
Photon funnels for one-way energy transfer : multimetallic assemblies incorporating cyclometallated iridium or rhodium units accessed by sequential cross-coupling and bromination.

The generation of multimetallic assemblies is a widely explored theme, owing to the relevance of controlling energy and electron transfer between metal centres to many fields of contemporary importance. Boronic acid substituted coordination and organometallic complexes have been shown to be useful synthons in the formation of such structures through cross-coupling with halogenated complexes. In this work we used such a methodology to generate an octanuclear mixed-metal compound of composition Ir7Ru having a dendrimer wedge-like structure. The method combined cross-coupling with regiospecific bromination of phenylpyridine (ppy) ligands at the position para to the C–Ir bond. The propensity of Ir(ppy)2-based complexes to electrophilic bromination was found to be deactivated by the introduction of fluorine atoms. The coupling methodology was extended to rhodium-containing systems, exemplified by a tetranuclear system of composition Rh2Ir1Ru1. The synthesis required the use of boronic acid appended RhIII complexes, which could be accessed by the introduction of a neopentyl boronate ester appended bipyridine into the coordination sphere of RhIII. The excited-state energies of the constituent metal units in the resulting multinuclear complexes are such that unidirectional energy transfer occurs from the RhIII/IrIII branches to the RuII core. The luminescence thus resembles that of an isolated [Ru(bpy)3]2+ unit, but the ability of the structure to collect light is greatly enhanced
Ligand Rearrangement and Hemilability in Rhodium(I) and Iridium(I) Complexes Bearing Terphenyl Phosphanes

The synthesis of a series of cationic rhodium(I) and iridium(I) compounds stabilized by sterically demanding phosphanes that contain a terphenyl substituent PMeAr′ (Ar′ = 2,6-diarylphenyl) is described. Salt metathesis of metal precursors [MCl(COD)(PMeAr′)] (M = Rh, Ir; COD = cyclooctadiene) with NaBAr {BAr = B[3,5-CH(CF)]} resulted in a series of cationic complexes in which the loss of the chlorido ligand is compensated by the appearance of relatively weak π interactions with one of the flanking aryl rings of the terphenyl substituent. The same experiments carried out with carbonyl complexes [MCl(CO)(PMeAr′)] led to the corresponding cationic carbonyl complexes, the CO-induced rearrangement reactivity of which was investigated, both experimentally and computationally. The differences in reactivity between rhodium and iridium complexes and as a result of varying the sterics of terphenyl phosphanes are discussed.Peer Reviewe
PRELIMINARY CHEMICAL CHARACTERIZATION OF TUNISIN MONOVARIETAL VIRGIN OLIVE OILS AND COMPARISON  WITH  SICILIAN ONES.

Work was carried out on the characterization of monovarietal virgin olive oils (VOO)\ud
from Tunisia and Sicily (Italy). The two main Tunisian VOO (cvv. Chétoui of the North and\ud
cv. Chemlali grown in the Center and some regions of the South) and three principal\ud
Sicilian VOO (cvv. Nocellara del Belice, Biancolilla and Cerasuola) were studied.\ud
Moreover, the Chétoui oils were tested in a rain-fed control and an irrigation regime. All\ud
olive samples were picked at three different stages of ripeness. Analyses of major\ud
components (fatty acids and triacylglycerols) and minor ones (squalene, tocopherols\ud
and phenolic compounds) were carried out. Chétoui oils had a higher level of phenolic\ud
compounds followed by Chemlali. Generally, in the Sicilian oils these natural antioxidant\ud
contents were lower. These preliminary results indicate that it was possible to\ud
classify the Tunisian and Sicilian oils tested in their original growing area based on their\ud
chemical composition
Lipid deterioration during chilled storage of Atlantic Pomfret (Brama brama)

7 páginas, 4 tablas, 3 figurasLipid damage produced during Atlantic pomfret (Brama brama) chilled storage (up to 19 d) was studied. The formation of various lipid parameters, such as free fatty acid and conjugated dienes (CD), peroxide value, thiobarbituric acid reactive substances and fluorescent compounds was measured in 2 different white muscle zones (dorsal and ventral). The results were compared with the formation of volatile amines (total volatile base-nitrogen, TVB-N, trimethylamine-nitrogen, TMA-N). A gradual lipid hydrolysis was observed in both zones during the entire experiment. CD and peroxides formation was prominent during the experiment, whereas peroxides showed the highest value at day 15 in both zones followed by a peroxide breakdown at day 19. Interaction of oxidized lipids with nucleophilic compounds present in the fish muscle led to a gradual development of fluorescent material during storage in both zones. The mean value of the lipid content tended to be higher in the ventral zone than in the dorsal one, although significant differences could not be detected (p >0.05). Concerning the lipid damage, very small differences (p <0.05) could be assessed between both zones. TVB-N content showed no variation till day 15. At day 19, a sharp increase was observed for both muscle zones. In the case of TMA, a gradual increase was observed in both muscles during the 19-day storage. Higher mean values of TVB-N and TMA-N indices were obtained for the ventral than for the dorsal zone. This might be due to the fact that the ventral zone is close to the viscera, where microorganisms are known to concentrate. Of all the different indices tested for quality assessment, TMA-N and the formation of fluorescent compounds were strongest related to the duration of storage (r2≥0.87). These might therefore be the most accurate parameters to follow quality loss of chilled Atlantic pomfretThe authors acknowledge the Comisión Interministerial de Ciencia y Tecnología\ud
(CICyT) for financial support through the research\ud
project ALI 99-0869 (2000-2002).Peer reviewe
Studies on rancidity inhibition in frozen horse mackerel (Trachurus trachurus) by citric and ascorbic acids

9 páginas, 8 tablasThis study is aimed to investigate the effect of aqueous solutions of citric acid (CA) and ascorbic acid (AA) on the lipid stability of horse mackerel (Trachurus trachurus) fillets and whole fish during frozen storage (up to 6 and 9 months, respectively) by means of a soaking pretreatment. Best oxidation inhibition results on fish fillets were obtained when employing a 0.5% CA solution. Lower (p <0.05) peroxide (month 3), thiobarbituric acid-reactive substance (months 1 and 3) and fluorescent compound formation (month 6) values were obtained from CA-treated fish fillets than from the untreated (blank control) and water-treated (water control) fish fillets. In the case of whole fish, soaking pretreatment with a mixture consisting of 0.5% CA and 0.5% AA showed the best results in inhibiting oxidation, as lower (p <0.05) peroxide formation was observed at 6 and 9 months of frozen storage compared to the untreated or water-soaked counterparts. Advantages of both acids (CA and AA) are discussed, and further studies based on the positive role of a CA-AA mixture will be carried out to extend the shelf life of medium- and high-fat content fish species during frozen storageThe authors acknowledge the Comisión\ud
Interministerial de Ciencia y Tecnología (CICyT) for financial\ud
support through the research project ALI 99-0869\ud
(2000–2002).Peer reviewe
Effect of advanced chilling methods on lipid damage during sardine (Sardina pilchardus) storage

7 páginas, 2 figuras, 4 tablasSlurry ice is a biphasic system consisting of small spherical ice crystals surrounded by seawater at subzero temperature. Its effect on lipid damage (hydrolysis and oxidation) was evaluated during the chilled storage of a fatty fish species, sardine (Sardina pilchardus). Slurry ice treatment was checked alone and in combination with ozone and compared to traditional flake icing during a 22-day storage. Different lipid damage indices (free fatty acids, FFA; peroxide value, PV; thiobarbituric acid index, TBA-i; fluorescent compounds, FR) were checked and compared to sensory assessment and nucleotide degradation (K value). According to lipid hydrolysis (FFA) and oxidation (PV and FR) developments, slurry ice showed an inhibitory effect (p <0.05) on lipid damage during storage, as well as an inhibition of nucleotide autolytic degradation. Ozonised slurry ice did not provide differences (p >0.05) from slurry ice alone when considering lipid hydrolysis, nucleotide degradation and some lipid oxidation indices (PV and FR), although a higher (p <0.05) TBA-i was observed at day 22 of storage when compared to flake ice and slurry ice treatments. However, a lower (p <0.05) fluorescence development was observed for fish treated under ozonised slurry ice when compared to traditionally iced fish. Sensory assessment showed a higher shelf life for fish samples treated under ozonised slurry ice than for their counterparts under slurry ice (15 d versus 12 d), while flake icing led to a far shorter shelf life (5 d). According to sensory and biochemical (lipid matter and nucleotide) analysis, slurry ice has proved to be a promising technology for damage inhibition and quality retention in a fatty fish species such as sardine. Ozonised slurry ice was also shown to be useful, since a longer shelf life was obtained in the present experiment and a pro-oxidant effect of ozone on sardine lipids was not provedThis work was supported by the\ud
Secretaría Xeral de I1D fromthe Xunta de Galicia (Galicia,\ud
Spain) (Project PGIDIT02RMA18E).Peer reviewe
Rancidity development during the chilled storage of farmed Coho salmon (Oncorhynchus kisutch)

7 páginas, 4 figuras, 2 tablasCoho salmon (Oncorhynchus kisutch) is a fatty fish species whose farming production has greatly increased in recent years. Lipid damage produced during Coho salmon chilled storage was studied for up to 24 d. Lipid hydrolysis (free fatty acids, FFA) and oxidation (conjugated dienes; peroxide value, PV; thiobarbituric acid index, TBA-i; fluorescent compounds formation, FR; browning development) were determined and compared to lipid composition (polyene index, PI; astaxanthin, AX) changes and sensory assessment (rancid odour development) results. Most lipid damage indices developed slowly during storage; thus, values obtained for FFA, PV, TBA-i and FR were in all cases under 1.5 g/100 g, 4.0 meq oxygen/kg lipid, 0.40 mg malondialdehyde/kg muscle and 0.40, respectively. Odour assessment showed a significant (p <0.05) rancidity development at day 10, when compared to starting fish material; then, non-acceptable values were obtained at days 19 and 24. The PI analysis showed not many differences during the storage time, with the lowest mean value at day 19. AX analysis indicated a relatively high content in the white muscle, which was maintained till the end of the experiment. A low oxidation development is concluded for Coho salmon lipids when compared to other fatty fish species under the same chilling conditions. AX was found to contribute to the oxidation stability of Coho salmon lipids, due to its free radical scavenger propertiesPeer reviewe
Synthesis of alkenyl succinic anhydrides from methyl esters of high oleic sunflower oil

Alkenyl succinic anhydrides (ASA) have been prepared by ene‐reaction of high‐oleic sunflower oil methyl esters with maleic anhydride in a 50% xylene medium. Response surface methodology (RSM) was used to investigate the influence of two factors: reaction temperature and molar ratio between maleic anhydride (MA) and methyl esters (SME). The studied parameters in 8‐h reactions were the methyl oleate conversion, the distillation yield in ASA, and responses allowing the indirect estimation of side reaction products: clarity index and dynamic viscosity. The highest yield in ASA (>70%; clarity index ≈10) was reached for a temperature of 240–250 °C with a molar ratio of 1.5–1.7. But for an industrial application requiring minimized side products (clarity index >40), the optimal synthesis conditions were: temperature between 220 and 235 °C and molar ratio of 1.2–1.35 (yield ≈55%). Such conditions did not provide a medium free of side products, even if xylene decreased their formation. Compared to solvent‐free synthesis, conversion was lower with xylene. With solvent, higher temperatures were needed to reach the same yields. Supplementary heating compensated the reagent dissolution effect that slows down the kinetics of the ene‐reaction. The influence of reaction time at 220 °C with a MA/SME ratio of 1.2 in a 50% xylene medium was studied. A reaction time of 8–10 h provided a good compromise between ASA yield and side products
Quality enhancement of canned sardine (Sardina pilchardus) by a preliminary slurry ice chilling treatment

8 páginas, 4 tablasThe slurry ice technology has shown wide advantages when employed as a chilling method for marine species instead of the traditional flake ice storage. In the present work, the use of slurry ice was evaluated for the first time as a technological treatment prior to the canning processing of fish. Thus, sardine (Sardina pilchardus) specimens were stored in slurry ice for 2 and 5 days and then taken and subjected to canning. Quality assessment of the canned product was performed on the fish muscle and on the coating oil, in comparison with that of a parallel control batch previously stored in flake ice. Analyses included composition (water, lipid and NaCl contents), physical properties (firmness, cohesivity), volatile amine formation (total and trimethylamine), lipid oxidation development (anisidine value, polyene index, -tocopherol content and Rancimat oxidative stability) and interaction compounds formation (fluorescence assessment). An inhibition of lipid oxidation development (p <0.05) was obtained in canned sardine when applying slurry ice as a preliminary chilling storage system. The present work opens the way to the use of slurry ice instead of flake ice as a preliminary treatment of fish material prior to the canning process.The work was supported by the Secretaría Xeral\ud
de I1D from the Xunta de Galicia (Galicia, Spain) (Project\ud
PGIDIT02RMA18E).Peer reviewe
Lipid damage during frozen storage of Gadiform species captured in different seasons

9 páginas, 4 figuras, 5 tablasQuality loss of two gadiform fish species (blue whiting, Micromesistius poutassou;\ud
hake, Merluccius merluccius) during frozen storage (–30 and –10 7C; up to 12 months)\ud
was studied. For this, hydrolytic (formation of free fatty acids, FFA) and oxidative\ud
(conjugated dienes, peroxide and interaction compound formation) lipid damage were\ud
analysed. For both species, individual fishes captured in two different trials (May and\ud
November) were considered. Increasing (p ,0.05) lipid hydrolysis and oxidation (peroxide\ud
and interaction compound formation) were observed for all kinds of samples\ud
throughout the frozen storage. Interaction compound detection by fluorescence analysis\ud
showed the best correlation values with storage time. Some higher (p ,0.05)\ud
hydrolysis development could be observed in hake captured in May than in its counterpart\ud
from the November trial, while frozen blue whiting did not provide definite differences\ud
for FFA formation between both trials. Concerning peroxide formation, higher\ud
(p ,0.05) values were obtained for individual blue whiting and hake captured in\ud
November when compared to their corresponding May fish for both frozen storage\ud
conditions. Interaction compound formation was also found to be higher (p ,0.05) for\ud
November hake fish than for its counterpart captured in May, while blue whiting did not\ud
provide definite differences between trials.The authors wish to thank the\ud
Secretaría Xeral de I1D (Xunta de Galicia, Spain) for\ud
financial support through the research project PGIDIT 04\ud
TAL 015E.Peer reviewe
Differentiation of mixtures of monovarietal olive oils by mid-infrared spectroscopy and chemometrics

Fourier transform infrared (FT-IR) spectroscopy in combination with chemometric techniques has become a useful tool for authenticity determination of extra-virgin olive oils. Spectroscopic analysis of monovarietal extra-virgin olive oils obtained from three different olive cultivars (Erkence, Ayvalik and Nizip) and mixtures (Erkence-Nizip and Ayvalik-Nizip) of monovarietal olive oils was performed with an FT-IR spectrometer equipped with a ZnSe attenuated total reflection sample accessory and a deuterated tri-glycine sulfate detector. Using spectral data, principal component analysis successfully classified each cultivar and differentiated the mixtures from pure mono-varietal oils. Quantification of two different monovarietal oil mixtures (2-20%) is achieved using partial least square (PLS) regression models. Correlation coefficients (R2) of the proposed PLS regression models are 0.94 and 0.96 for the Erkence-Nizip and Ayvalik-Nizip mixtures, respectively. Cross-validation was applied to check the goodness of fit for the PLS regression models, and R 2 of the cross-validation was determined as 0.84 and 0.91, respectively, for the two mixtures.CODA (MIRG-CT-2005-029134) project supported by an EU Marie Curie Reintegration Gran
Factors affecting droplet size of sodium caseinate-stabilized O/W emulsions containing β-carotene

This work was initiated to prepare an oil-in-water (O/W) emulsion containing -carotene by microfluidization. The -carotene was dissolved in triolein and microfluidized with an aqueous phase containing sodium caseinate (SC) as the emulsifier. Microfluization at 140 MPa resulted in O/W emulsions with a mean droplet diameter of ca. 120 nm, which was further confirmed by transmission electron microscopy analysis. The influences of SC concentration and microfluidization parameters on the droplet size of the emulsions were studied. The results showed that the mean droplet diameter decreased significantly (p <0.05) from 310 to 93 nm with the increase in SC concentration from 0.1 to 2 wt-%. However, a further increase in SC concentration did not much change the droplet diameter, although the polydispersity of the emulsions was slightly improved. The droplet diameter of the emulsions was found to decrease from 200 to 120 nm with increasing microfluidization pressure, with narrower droplet size distribution. The storage study showed that the emulsions were physically stable for about 2 weeks at 4 °C in the dark. The results provide a better understanding of the performance of SC in stabilizing the O/W emulsions
Kinetics and mechanism of the reaction between maleic anhydride and fatty acid esters and the structure of the products

Alkenyl succinic anhydrides (ASA) were obtained by reaction between maleic anhydride and high‐oleic sunflower oil (HOSO) esters. A kinetics study of the maleinization of alkyl esters indicated that the maleinization reaction was second order overall and first order with respect to the individual reactants, and the activation energy was 77.2 ± 3.3 kJ/mol in the investigated temperature range (185–225 °C). These results showed that the cis configuration and the central position of the double bond in HOSO esters facilitate the maleinization of the latter. On the contrary, the length of the linear ester moiety had no influence on the course of the maleinization reaction. Moreover, new evidence demonstrates that there are two different reaction mechanisms: ene‐reaction and addition in allylic position with a 2 : 1 ratio, respectively. This ratio was constant throughout the reaction, thus indicating that these mechanisms are independent
Lipid damage in farmed rainbow trout (Oncorhynchus mykiss) after slaughtering and chilling storage

9 páginas, 5 tablas, 2 figurasThe flow ice system including ozone (OFI condition) was tested for slaughtering and storage (up to 16 days) of farmed rainbow trout (Oncorhynchus mykiss). Lipid damage analyses were carried out and compared to sensory acceptance and instrumental colour changes. Comparison to individuals processed with the flow ice system in the absence of ozone (FI condition) was undertaken. Rainbow trout slaughtered and chilled under FI and OFI conditions showed a low lipid damage development, according to lipid oxidation and hydrolysis events and lipid composition (polyunsaturated fatty acids, phospholipids and endogenous antioxidants) changes. Additionally, both icing conditions led to largely good quality and shelf life times and to the absence of changes in colour properties. It is concluded that flow ice as such, or including the presence of ozone, can be considered as ideal strategy to be employed as slaughtering and storage system during the commercialisation of the actual farmed species. The ozone presence has shown some profitable effects as leading to an extended shelf life time by quality retention of several sensory parameters; in contrast, some negligible negative effects could be observed on the secondary and tertiary lipid oxidation development. However, the oxidation values reached by individuals kept under OFI conditions cannot be considered as particularly highThis work was\ud
supported through a project grant by the Secretaría Xeral de I1D\ud
from the Xunta de Galicia (Project PGIDIT 05 TAL 00701CT)Peer reviewe
Consecutive reactions in an oleic acid and acetic anhydride reaction medium

When mixing acetic anhydride and oleic acid, two consecutive reactions take place. The first one yields acetic‐oleic anhydride (AOA) and acetic acid. In the second one, oleic acid reacts with AOA to form oleic anhydride at 5% in a mixture when the initial molar ratio is 1:1. Therefore, at equilibrium, the global reaction yields a mixture of AOA, acetic anhydride, oleic acid, acetic acid and oleic anhydride. Based on a new HPLC protocol, all the species of the reaction medium could be separated and quantified. This permitted for the first time to study the kinetics and thermodynamics of the reaction. In the 30–70 °C range, reactions were of order 2 with partial orders of 1 for each reactant. Equilibrium constants were determined for both reactions. Enthalpy, entropy and activation energies were calculated for the main reaction. The influence of molar ratio on the composition at equilibrium was also investigated. The synthesis of AOA could thus be understood and new data were obtained for this singular molecule scarcely cited in the CAS database
Comparison of fatty acid profiles and mid-infrared spectral data for classification of olive oils

The composition of olive oils may vary depending on environmental and technological factors. Fatty acid profiles and Fourier-transform infrared (FT-IR) spectroscopy data in combination with chemometric methods were used to classify extra-virgin olive oils according to geographical origin and harvest year. Oils were obtained from 30 different areas of northern and southern parts of the Aegean Region of Turkey for two consecutive harvest years. Fatty acid composition data analyzed with principal component analysis was more successful in distinguishing northern olive oil samples from southern samples compared to spectral data. Both methods have the ability to differentiate olive oil samples with respect to harvest year. Partial least squares (PLS) analysis was also applied to detect a correlation between fatty acid profile and spectral data. Correlation coefficients (R2) of a calibration set for stearic, oleic, linoleic, arachidic and linolenic acids were determined as 0.83, 0.97, 0.97, 0.83 and 0.69, respectively. Fatty acid profiles were very effective in classification of oils with respect to geographic origin and harvest year. On the other hand, FT-IR spectra in combination with PLS could be a useful and rapid tool for the determination of some of the fatty acids of olive oils.CODA (MIRG-CT-2005-029134); EU Marie Curie Reintegration Gran