Validation of antibiotics in catfish by on-line solid phase extraction coupled to liquid chromatography tandem mass spectrometry.

For the first time automated on-line solid phase extraction coupled to liquid chromatography tandem mass spectrometry was developed for the simultaneous determination of 13 antibiotics (sulfonamides and tetracyclines) in catfish. The method proposed was validated according to Commission Decision 2002/657/EC, showing good linearity between 2 and 350 µg kg(-1), high recovery (80-99%) and reproducibility (13-20%) values, lower detection limits than 0.1 µg kg(-1), and quantification limits under 2.4 µg kg(-1) (between 39 and 84 times lower than the MRL fixed by the EU). Moreover, the proposed method was also used to determine sulfonamides and tetracyclines in 16 out of 107 samples, all previously analysed by microbiological screening that gave positive results. Five out of 13 antibiotics were found, having tetracycline the higher occurrence (10 samples); in all cases the concentrations were lower than the MRL established.

Increasing the applications of Crocus sativus flowers as natural antioxidants.

UNLABELLED: Large amounts of floral bio-residues (92.6 g per 100 g of flowers) are generated and wasted in the production of saffron (Crocus sativus) spice. Progress in mechanization of saffron crop offer the opportunity to expand the uses of C. sativus flowers, beyond the spice (dried stigmas). The antioxidant potential of flowers of saffron, their separate parts (tepals, stamens, styles, and stigmas) and floral bio-residues were evaluated by 4 in vitro assays: lipid peroxidation, deoxyribose assay, Rancimat test, and Trolox equivalent antioxidant capacity. Phenolic content and crocetin ester composition were also determined. All the samples studied showed to be potential antioxidants. The highest phenolic, flavonoid, and anthocyanin contents were observed in tepals. Stamens showed lower phenolic, flavonoid, and anthocyanin contents than those of whole flowers, tepals, and floral bio-residues. Crocetin esters were not found in tepals or stamens. Stamens exhibited the most potent LOO(•) and OH(•) radicals scavenging activity, being higher than those of food antioxidant propyl gallate. Flowers of saffron, tepals, stamens, styles, and floral bio-residues showed LOO(•), OH(•), and ABTS(•-) radicals scavenging activity, while stigmas showed LOO(•) and ABTS(•-) radicals scavenging activity. All samples studied improved the oxidative stability of sunflower oil in Rancimat test. These antioxidant properties could suggest the application of this floral material as functional ingredients with the subsequent added value. PRACTICAL APPLICATION: Saffron spice, the most valuable spice worldwide, is the dried stigma that only represents 7.4% of Crocus sativus flowers. Other parts of the flowers different to stigmas are discarded. Flower harvest and all the postharvest steps to produce saffron spice are performed manually. Mechanization of flower collection, stigma separation, and dehydration process is a revolution in saffron spice production, which increases the productive capacity making it possible to extend the uses of C. sativus flowers, beyond the production of saffron spice. Flowers possessed high-phenolic content and excellent antioxidant properties that could contribute to their application as functional ingredients.

Geographical origin differentiation of saffron spice (Crocus sativus L. stigmas) - Preliminary investigation using chemical and multi-element (H, C, N) stable isotope analysis.

A preliminary study of the bulk hydrogen, carbon and nitrogen stable isotope composition of 28 authentic saffron samples produced from Crocus sativus L. cultivated in the typical production areas of Western Macedonia in Greece (8), Khorasan Province in Iran (7), Sardinia in Italy (6) and Castilla-La Mancha in Spain (7) is described. A chemical characterisation of 16 key quality parameters was also completed on the same samples by UV-Vis, HPLC and GC analyses. Multivariate analysis of the data revealed that 60.7% of saffron samples could be correctly assigned to their respective production countries using the chemical parameters. However, the combined bio-element stable isotope data reliably classified 100% of the saffron samples according to their respective geographical origins using posterior cross validation. Further work is required to establish the long-term stability of these models with respect to different years of production and other major producers such as India and Morocco.

Quantification of crocetin esters in saffron (Crocus sativus L.) using Raman spectroscopy and chemometrics.

The feasibility of Raman spectroscopy for predicting the content of crocetin esters (crocins), and coloring strength was assessed. 114 samples from Greece, Iran, Italy and Spain were divided into two sets: a calibration set with 49 samples and a validation one with 65 samples. Calibration models for crocetin esters (r 0.97, RMSEC 0.92, RMSEP 0.97, RPD 3.46) and coloring strength (r 0.95, RMSEC 12.2, RMSEP 11.3, RPD 2.59) were built in the spectral region 1700-955 cm(-1) using partial least-squares (PLS) regression. The calibration models were validated using cross-validation, leaving one sample out (r 0.97, RMSECV 1.09 for crocetin esters and r 0.93, RMSECV 14.5 for coloring strength). The crocetin esters content as determined by liquid chromatography fluctuated between 18.8 and 31.7 mg/100 g saffron. The corresponding values, as calculated using the Raman method, fluctuated between 19.2 and 32.0 mg/100 g saffron. The coloring strength determined by the reference method ranged from 177.0 to 296.7 units, while with the Raman method the values were between 186.8 and 297.6 units. The results, as compared to the reference methods (liquid chromatography and UV-vis spectrophotometry), show that the proposed methodology gives data with acceptable accuracy. The proposed models can be used as a tool for rapid screening of quality in saffron samples.

Effects of mild temperature conditions during dehydration procedures on saffron quality parameters.

BACKGROUND: The dehydration procedure is responsible for saffron sensorial properties: colour, taste and aroma. Changes in the compounds responsible for these characteristics have been studied when dehydration processes at high and low temperature are employed. However, the evolution of these changes at mild temperatures is not available in the current bibliography. In this paper the effect of different mild conditions (18-20 degrees C for 24 h, 40-50 degrees C for 75 min and 55 degrees C for 75 min) applied to 45 saffron samples with the same origin was investigated. RESULTS: Crocetin esters, the compounds responsible for saffron colour, increased their content with no significant differences from other processes when high temperatures (55 degrees C) were used, thus producing a noticeable increment in saffron colouring capability. Similar behaviour was obtained for picrocrocin, the compound responsible for saffron taste, with higher average content at the highest temperature (55 degrees C) but without significant differences with the inferior conditions (40-50 degrees C). However, more volatile compounds were generated, especially safranal,at higher temperatures, e.g. 55 degrees C, during the dehydration procedure. CONCLUSIONS: The results found support the idea for employing mild to high temperatures during the dehydration process of saffron.

Picrocrocin content and quality categories in different (345) worldwide samples of saffron ( Crocus sativus L.).

In this paper, 345 saffron samples were analyzed from different countries to study their picrocrocin content using different analytical techniques. The E1cm 1% of 257 nm results from all samples are inflated in comparison by the high-performance liquid chromatography (HPLC) data, because of the interferences with the crocetin ester pool and especially with those with a lower trans/cis relation. A picrocrocin range update is proposed for International Organization for Standardization (ISO) 3632 normative because category III should be incremented up to 50 units, while category II should be incremented up to 60 units. More accurate data are achieved when the deltaEpic measurement is carried out. Consequently, improvements to the ISO method are suggested. Fourier transform (FT)-near-infrared spectrometry analysis has also been carried out, showing excellent results from the calibration with HPLC data. This spectrophotometric technique could be used by saffron enterprises to obtain quick and more accurate data for picrocrocin determination.

Parabens as agents for improving crocetin esters' shelf-life in aqueous saffron extracts.

The effect of parabens on the shelf-life of crocetin esters and picrocrocin in aqueous saffron solutions was studied. Degradation of saffron crocetin esters fits a first-order kinetics model, and the results indicated that the crocetin (beta-D-glucosyl)-(beta-D-gentiobiosyl) esters were more stable than the crocetin di-(beta-D-gentiobiosyl) esters regardless of whether trans and cis isomers were considered. Under all tested conditions both parabens gave good results, especially propyl paraben that showed a greater influence on the degradation rate constant, except for cis-crocetin di-(beta-D-gentiobiosyl) ester and cis-crocetin (beta-D-glucosyl)-(beta-D-gentiobiosyl) ester. In presence of propyl paraben (200 mg/L), the half-life periods of trans-crocetin di-(beta-D-gentiobiosyl) esterimproved considerably, up to four-fold. Special attention has been paid to the effect of propyl paraben on 46 saffrons with different crocetin ester contents. No differences were observed in terms of picrocrocin. By analysis of variance, it is noteworthy that there were differences between the mean content of crocetin esters for all analysed saffron, except for trans-crocetin (beta-D-glucosyl)-(beta-D-gentiobiosyl) ester.

Multi-residue contaminants and pollutants analysis in saffron spice by stir bar sorptive extraction and gas chromatography-ion trap tandem mass spectrometry.

A method for the simultaneous determination of 46 semi-volatile organic contaminants and pollutants in saffron has been developed for the first time using a stir bar sorptive extraction technique and thermal desorption in combination with gas chromatography-ion trap tandem mass spectrometry. The analytical method proposed was easy, rapid and sensitive and showed good linearity, accuracy, repeatability and reproducibility over the concentration range tested. Moreover, the correlation coefficients were higher than 0.98 for all target compounds and detection limits were lower than 1 microg/kg except for simazine. The present method was also applied for the analysis of trace contaminants in saffron samples.

Comparison of stir bar sorptive extraction and solid-phase microextraction to determine halophenols and haloanisoles by gas chromatography-ion trap tandem mass spectrometry.

Solid-phase microextraction by immersion (IS-SPME) and headspace mode (HS-SPME), together with stir bar sorptive extraction (SBSE), have been assayed in combination with gas chromatography-ion trap tandem mass spectrometry (MS/MS) for analysing 2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol, 2,4,6-tribromophenol, 2,4,6-trichloroanisole, 2,3,4,6-tetrachloroanisole and 2,4,6-tribromoanisole in different liquid matrices. Once, the optimization of MS/MS fragmentation analysis was carried out, sample enrichment was performed using the three mentioned extraction methods, and comparison through the determination of linearity, and LOD and LOQs were carried out. SBSE and IS-SPME methods described enabled us to determine the target compounds at ng/l levels, concentrations lower than their olfactory threshold, which is not the case of HS-SPME. SBSE showed a higher concentration capability than both SPME techniques, especially when compared to the HS-SPME mode. Thus, SBSE should be the definitive technique to analyse halophenols and haloanisoles in aqueous matrices. SBSE has been also applied to nine aqueous matrices as different as tap water, wines or commercial lemon juice extract.