Search

In this work is reported the development and application of an amperometric biosensor for the determination of total biogenic amines content by using the commercial diamino oxidase (DAO from Porcine kidney E.C. 1.4.3.6) as the biocomponent, entrapped by glutaraldehyde onto an electrosynthesized bilayer film. In order to minimize both the fouling and the interference caused by the direct electrochemical oxidation of both the analytes (i.e., biogenic amines) and the common interferents usually present in food products the performances of Pt and Au electrodes and of several electroproduced anti-interferents mono- and bi-layer films were tested. In spite of a very low activity of the commercial DAO, the biosensor displayed a high response sensitivity in flow experiments, short response time, a good linear response and low detection limits. The excellent anti-interference characteristics allowed the use of the biosensor in screening analysis of food products.

The effect of different surface treatments (with olive oil, liquid smoke or pimaricin) on a number of physico-chemical characteristics (namely, moisture, NaCl content, pH, total and soluble nitrogen fractions, lipolytic processes and mould production) of the core and the rind zones of Canestrato Pugliese cheese were studied during the whole ripening period (100 days). Treated cheese data were statistically compared with data obtained for untreated cheese. While for the core zone proteolytic and lipolytic processes, together with all the other physico-chemical properties studied, remained unaffected by the surface treatment, in the layer close to the rind these were influenced significantly by the surface treatment in a manner correlated with the fungal growth.

SUMMARY The use of fuels derived from vegetable oils represents a potential opportunity to meet EU Commission guidelines promoting renewable energy utilization. This is particularly true for Mediterranean countries where farmers are well familiarized with oil crops. Sunflower is one of the most adapted crops to dry conditions typical of Mediterranean environments. The oleic acid content in sunflower oil seems to be a suitable character for biofuel production with regard to fuel oxidative stability. For the same reason, the high oleic varieties are considered particularly promising. In this study the effect of climatic conditions and agronomic practices on oleic acid content of sunflower seeds is investigated with respect to the Southern Italy regions. Effects of high temperature, water deficit, irrigation water quality, sowing time and genotype on oil yield and quality are evaluated. Finally, the potential of sunflower cultivation for biofuel production in the light of the recent European agricultural policy is discussed.

Sunflower is a species moderately tolerant to salt stress and is currently cultivated in dry areas where salinity can be a threat. The effect of salt stress on achene yield has been investigated, but no information exists about its effect on the oil fatty acid composition. The aim of this paper was to evaluate the changes in oil yield and fatty acid composition in a high oleic hybrid submitted to different salinity levels of irrigation water. Furthermore, since the addition of a leaching fraction to the irrigation volume may be relevant to prevent excessive soil salinization, a water regime equal to 1.5 maximum evapotranspiration (1.5 ETc) was compared with the restoration of evapotranspiration (1 ETc). A pot experiment was carried out in a greenhouse with a high oleic sunflower hybrid (Platon) grown on a loam soil under two irrigation regimes with five salinity levels of irrigation water (0.6, 3, 6, 9 and 12 dS m −1 ). At harvesting, seed production, oil yield and fatty acid composition were determined. The percent seed yield decrease per unit increase of irrigation water electrical conductivity (ECw) was higher for 1 ETc (7%) than for 1.5 ETc (5.8%). Oil yield showed a significant decrease from 38.3 to 3.4 g per head on increasing salt stress and a marked increase of about 50% with the higher irrigation volume. Under our experimental conditions with a medium textured soil, this result confirms the importance of leaching to limit salt accumulation along the soil profile, thus reducing seed and oil yield drop under salt stress. Concerning fatty acid oil composition, under all the adopted experimental conditions, both oleic and linoleic acid accounted together for 90% of total fatty acid concentration, while stearic and palmitic acid were about 4%. No great differences were observed in fatty acid composition between the two irrigation regimes. With the higher irrigation volume, only a slight decrease in linoleic and gadoleic acid and an increase in arachidic acid were observed. The only significant differences among saline treatments were observed for oleic and linoleic acid. Oleic acid showed an increase from 82.8% in the control to 86.8% at the highest salinity treatment. Inversely, for linoleic acid a progressive decrease from 6.9 to 2.8% with increasing salinity level was observed. These results will be discussed in the light of a possible inhibition of oleate desaturase occurring under salt stress.

Sunflower is one of the most cultivated oil crops in the world. Recently, high oleic acid cultivars have been developed whose oil has higher oxidative stability and better dietary properties than standard genotypes. In Mediterranean environments where water deficit frequently occurs, early sowing and irrigation are used to overcome environmental constraints due to water scarcity. Since, in the literature, the data on the effect of these agronomic techniques on sunflower oil quality are scarce and contrasting, the aim of this paper was to evaluate the effect of the sowing time and the water regime on seed yield and oil quality of high oleic hybrids in a Mediterranean environment. For this purpose, two high oleic hybrids (Platon and Vyp70) sown in spring at two different dates were cultivated in southern Italy under two water regimes (irrigated and non-irrigated) in 1996 and 1997. Yield and its main components were positively affected by irrigation and by the earlier sowing date. With regard to fatty acid composition, a decrease in oleic and stearic acid and an increase in linoleic and palmitic acid were observed under irrigation. At early sowing, oleic and palmitic acid decreased whereas linoleic and stearic acid increased. The decrease in the oleic/linoleic acid ratio observed at early sowing and under irrigation, suggests a possible role of temperature on the activity of oleate desaturase in the developing seeds.

The effects of intramuscularly administrated vitamin E on total lipids, fatty acid profile, and lipid stability to oxidation was investigated in lamb liver. Twenty-four 5-day-old lambs were allotted to 4 groups of 6 each and given respectively 0 (control), 125, 200, 300 mg dl-alpha-tocopheryl acetate weekly from day 5 to 33. alpha-Tocopherol stored in lamb liver at the end of experiment showed linear correlation with the level of injected vitamin E. No effect on total lipids was found. A decrease in the level of liver thiobarbituric-acid reactive substances (TBARS), significantly correlated with liver alpha-tocopherol content, was found in vitamin E groups. The amount of linoleic and linolenic acids significantly increased in the vitamin E groups as compared to control group, and were correlated with the liver alpha-tocopherol content. TBARS were negatively correlated with the concentration of unsaturated fatty acids. Finally, in the liver of the treated groups, vitamin E concentrations in the range 30–50 mug/g showed adequate for an efficient protection from peroxidation of membrane lipids, and determined an increase in the unsaturated to saturated fatty acid ratio.

Comisana ewes (27) were divided into three groups of nine. Control group was fed a vetch and oat hay and a pelleted concentrate. The other two groups were given the control ration supplemented with 4 and 8% rumen-protected fat. The feeding treatment caused significant variations in the characteristics of milk, and these variations showed a good correlation with the level of protected lipids in diets. Caproic acid (C6:0), caprylic acid (C8:0), capric acid (C10:0), lauric acid (C12:0) and myristic acid (C14:0) contributed mostly in the control group, while palmitic acid (C16:0), oleic acid (C18:1) and linoleic acid (C18:2) were predominant in the groups fed with the supplemental rumen-protected fat. Also, a significant increase in the ratio between medium- and long-chain fatty acids (C16:0+C18:1+C18:2) and short-chain fatty acids (C6:0+C8:0) was found to be a major source of variation related to the rumen-protected fat supplementation. Dietary lipid supplementation was effective in improving the unsaturated-to-saturated fatty acid ratio in milk (P

Studies have been carried out to assess the provenance of selected pottery excavated at archaeological sites near Canosa, Puglia (Italy). Sixty-six sherds, ranging in date from the mid-seventh century BC to the beginning of the third century BC, were analysed by atomic absorption spectroscopy and 16 elements were determined. The analysis data were subjected to multivariate classification procedures. Tests showed that the majority of the examined sherds came from ancient local kilns; a probable Ionian origin was established for some other sherds, while the rest were of unknown origin.

A method based on reversed-phase HPLC with UV detection is described for the determination of the impurity aminopropiophenone in phenylpropanolamine bulk drugs and compressed tablets. The only sample preparation necessary for the analysis is its dilution with the mobile phase. The practical detection limit is 30 ppm. The method has been applied for the analysis of commercial samples.

CuO-based cathodes partially discharged using high-density current have been studied by analytical electron spectroscopies with the aim of elucidating the cell-discharge mechanism with particular reference to the formation of an LixCuO intercalation phase. The most interesting spectroscopic data of involved Cu species are reported and discussed. The disappearance of CuII at the cathode surface just at the beginning of the cell discharge and the formation of CuO and/or CuI were observed. The calculated modified Auger parameter values allowed characterization of CuI and CuO and distinction to be made between them when both were present. The presence of CuI has been rationalized on the base of an after-discharge solid-state reaction between electrochemically produced metallic copper and the underlying CuO. These results, together with the inhomogeneous depth profile of Li species concentration, seem to exclude the hypothesis of the formation of a genuine intercalation phase. At the same time an alternative explanation based on a ‘porous electrode’ model is suggested for the electroanalytical data reported by other authors and interpreted in terms of the formation of an intercalation phase.

Durum wheat ( Triticum turgidum L. var. durum ) is an important cereal crop extensively cultivated in Mediterranean areas, whose grain is predominantly used for pasta making. Ten durum wheat cultivars were cultivated during two consecutive years in the same area following both conventional and organic farming systems (CFS and OFS, respectively). The content of six heavy metals (i.e., Cd, Cr, Cu, Ni, Pb, and Zn) in soil and semolina samples from 10 different wheat cultivars was assessed, and the effect of conventional and organic fertilizers on these heavy metal contents evaluated. Although significantly higher heavy metal input to soil was provided by adding the organic fertilizer, semolina samples obtained from the cultivars grown in CFS were richer in Cd (82 μg kg −1 vs. 18 μg kg −1 ), Cr (182 μg kg −1 vs. 50 μg kg −1 ), and Cu (6.6 μg kg −1 vs. 5.8 μg kg −1 ), thus suggesting a potential for the organic system to reduce the amount of these elements in the soil solution, to limit their availability and uptake by plants, and to influence their translocation processes to grains. On the other hand, semolina samples obtained from OFS showed higher concentrations of Ni (295 μg kg −1 vs. 166 μg kg −1 ), Pb (94 μg kg −1 vs. 82 μg kg −1 ), and Zn (13.6 mg kg −1 vs. 10.8 mg kg −1 ) with respect to those obtained from CFS. These differences in heavy metal content among semolina samples obtained from OFS and CFS were also clearly highlighted by the Principal Component Analysis that showed, according to bulk results, the opportunity of encouraging/discouraging some cultivars in relation to the adopted farming system and to the kind of metals to be preferentially accumulated or depleted.

The quantitative separation of the overlapped ESCA spectra of some mixtures of powders of chromium and lead compounds was performed by the Kalman filter algorithm. Noise baselines below peak were drawn by using cubic spline polynomials as smooth interpolators. Typical errors in the estimated concentrations of the components were less than 8%.

The characterization of carbon fibres by x-ray photoelectron spectroscopy depends on several experimental and theoretical aspects that noticeably improve the accuracy of the analysis when properly taken into account. These aspects are briefly discussed in the light of the most representative literature available. Attention is focused on points that need a deeper understanding and suggestions are given about possible analysis strategies.

The potential of a computational approach for the quantitative resolution of seriously overlapping chromatographic peaks when there is loss of collinearity between the pure component peaks and the mixture peak has been explored. The program makes iterative use of the Kalman filter algorithm for resolving the mixture peak with the component peaks aligned according to some values of the position parameters, and of a steepest descent minimization procedure to find the optimal alignment. This combined procedure has been applied to the quantitive resolution of the HPLC chromatograms of alternariol and altenuisol mycotoxins in synthetic mixtures and in real samples.

The potential of a new procedure for the quantitative analysis of ESCA spectra was exploited by determining the composition of powder mixtures of some chromium compounds. The quantitative separation of the overlapped Cr 2p peak doublets was accomplished by the Kalman filter algorithm. Background removal from the spectra was carried out by a new approach employing the cubic splines as smooth interpolators between the peak valleys. The results of the analyses compared well with those obtained by factor analysis (typical errors were ±4%). However, the Kalman filter operating recursively on the data points of the spectrum is preferable when the analysis is limited to only one mixture plus standards. Cubic spline interpolation was as effective as the Shirley method in yielding quantitative background subtraction.

We describe a new colorimetric method for the zinc assay in serum. The method uses the chromogen 4-(2-pyridylazo) resorcinol and, since it does not require any preconcentration step or specialized instrumentation and personnel, it is suitable for routine work in small laboratories. The correlation with the atomic obsorption spectroscopy method applied to wet-ashed samples is high (r2=0.9826). The mean within-assay CV is 6.7% and the mean between assay CV is 7%. The method was tested on a sample of 1253 individuals randomly chosen. The mean zinc concentration was statistically different between males and famales.

A procedure for the simultaneous quantitation of Al(III) and Cr(III) ions by reversed-phase HPLC, after pre-column complexation with 8-hydroxyquinoline, is described. The deconvolution of the partially overlapped peaks was by the Kalman filter method which yielded accurate and precise results. Background removal from the chromatograms was by a new approach employing cubic splines as interpolators between the peak valleys. Finally, it is shown that the Kalman filter deconvolution, after subtraction of the background by cubic spline interpolation, allowed quantitation of Al(III) and Cr(III) down to 25 ppb for each metal. These concentrations were not detectable by conventional integration methods due to a very low signal-to-noise ratio.

The effect of graded levels of dietary rumen-protected methionine (rp-Met) or lysine (rp-Lys) on the fatty acid composition of Comisana ewes' milk was investigated. The animals lambed in autumn and were separated from their lambs 7 weeks after parturition; they were divided into five groups of nine which were given different rations. The control group was fed on a mixture of vetch and oat hay with a pelleted concentrate; the other groups were given the control ration supplemented with rp-Met (3·5 or 7·0 g/kg) or rp-Lys (10·5 or 21·0 g/kg). Milk fatty acid composition was determined by gas chromatography, and these values were subjected to principal components analysis. A correlation was found between fatty acid composition and diet. We demonstrated that giving the experimental diets significantly affected milk fat, to an extent that was independent of the levels of the supplementary amino acids. The milk fat of the control group contained largely caprylic, capric and lauric acids, whereas that of the groups given the supplementary amino acids contained largely palmitic, palmitoleic, stearic and oleic acids. Thus supplementation resulted in an increase in the proportion of 16[ratio ]0–18[ratio ]3 (primarily palmitic and stearic) and a reduction in the proportion of 4[ratio ]0–12[ratio ]0 fatty acids. There was also a modest increase in the unsaturated: saturated fatty acid ratio.

The agricultural use of olive processing waste is a strategic resource in the integrated management of the agricultural system as it satisfies the two objectives of evacuating the olive-processing residue and using it beneficially for agricultural purposes. For such aims, a research was conducted in Bari (South of Italy) to study the effects of the incorporation into the soil of increasing amounts of non-fermented wet pomace (WP) (0, 17.5, 35, 70, 105, 140, 175, 210 Mg ha-1) on the oil yield and acid profile of sunflower seeds. The results obtained point out that the seed yield was negatively affected by the application of WP starting from 70 Mg ha-1; an opposite trend was observed for the seed oil yield. The incorporation of WP has also affected the oil fatty acids’ composition. Oleic and linoleic acids, the principal fatty acids (beyond 90% of total fatty acids), showed significant variations: from the control treatment to the one receiving the maximum application of waste, oleic acid decreased (-5.4%), linoleic acid increased (+ 6.6%), and the saturated fatty acids fraction decreased (-7.6%).

Among the objectives concerned in this research, much importance has been attached to the assessment of the influence of soil type, irrigation water quality and leaching requirement on the production and composition in fatty acids of sunflower oil. The trial was run in 2001 on a sunflower crop (cv. HS 90) grown in cylindrical pots at the Campus of Bari University (Italy). 36 treatments obtained from the factorial combination of two clay soils with nine types of brackish water and two leaching fractions (10 and 20%) were compared. The nine types of irrigation water were obtained by dissolving the proper amounts of NaCl and CaCl2 in de-ionized water, according to the factorial combination of three salt concentration levels (0.01, 0.032 and 0.064 M) with three sodium levels (SAR = 5, 15 and 45). At ripening the main yield traits, oil yield and acid composition of seeds were analysed. At the highest salinity level about 70% yield reduction, in terms of seeds per plant was observed. The oil yield and the final acid composition of seeds were significantly affected by soil type, leaching requirement, salinity and the SAR levels of irrigation water. A progressive decline in oil yield was recorded as the salt concentration and sodium level of irrigation solutions increased. As to the fatty acid composition, a gradual increase in oleic and linolenic acid content and a corresponding decrease in the other fatty acids were found as the salinity and sodium levels of irrigation water increased. The oleic/linoleic acid ratio too increased as the salinity increased. The salt and sodium-induced stresses of irrigation water reduced the seed and oil yields while still favouring a progressive increase in the oleic acid content and a slight decrease of linoleic, palmitic and stearic acids, thus improving oil quality. The results point out both the influence of the soil and the positive effect of sodium and salt stress and of the leaching fraction on the food quality of sunflower oil.

CuO-based cathodes partially discharged using high-density current have been studied by analytical electron spectroscopies with the aim of elucidating the cell-discharge mechanism with particular reference to the formation of an LixCuO intercalation phase. The most interesting spectroscopic data of involved Cu species are reported and discussed. The disappearance of CuII at the cathode surface just at the beginning of the cell discharge and the formation of CuO and/or CuI were observed. The calculated modified Auger parameter values allowed characterization of CuI and CuO and distinction to be made between them when both were present. The presence of CuI has been rationalized on the base of an after-discharge solid-state reaction between electrochemically produced metallic copper and the underlying CuO. These results, together with the inhomogeneous depth profile of Li species concentration, seem to exclude the hypothesis of the formation of a genuine intercalation phase. At the same time an alternative explanation based on a ‘porous electrode’ model is suggested for the electroanalytical data reported by other authors and interpreted in terms of the formation of an intercalation phase.

Polybithiophene (pbT) thin films have been electrochemically deposited on n-TiO2 prepared by electrochemical oxidation of titanium. The rectifying behaviour of this novel inorganic semiconductor/conducting polymer interface is demonstrated by cyclic voltammetry experiments, interpreted in the framework of Gerischer's theory on ‘semiconductor/redox-electrolyte’ interfaces treated as Schottky barriers. Moreover, experimental evidence of a photovoltaic effect is given by a photoelectrochemical investigation carried out by illuminating the pbT layer with photons of appropriate frequency.

A programmable scan controller to implement a fast access readout of individual photodiodes in a self‐scanned silicon photodiode array (SPDA) was assembled using transistor–transistor logic (TTL) presettable counters handled by a single‐chip microcontroller. This controller makes it possible to skip groups of unwanted diodes at fast scan rate, whereas the others are read and digitized at normal scan rate. The skipping scan rate (Fs) and the reading scan rate (Fr) are switch selectable, the former in the 4 MHz–250 kHz range, the latter in the Fs/2–Fs/4095 range. Any scan pattern is software programmable. Up to 29 groups of contiguous diodes can be skipped. Integration time and number of scans are also software programmable. Programming is accomplished by the host computer issuing the scan parameters through a strobed 8‐bit parallel port to the microcontroller, which provides for the controls necessary for the scan pattern generation required.

The anodic behaviour of pseudouridine a modified nucleoside proposed as tumoral marker, has been studied at a mercury electrode. A method for its determination in urine samples by liquid chromatography with indirect anodic polarographic detection has been developed. The method is simple, highly selective and permits the direct injection of urine after dilution (1∶20) with mobile phase. Creatinine, which also gave an anodic response on mercury, could be simultaneously determined and used as an “internal standard” for Psi. This allowed the pseudouridine/creatinine ratio determination in a single run on the same specimen and the use of urine samples collected randomly instead of the 24h collection. The within-day RSD% for pseudouridine/ creatinine peak areas ratio was 3.4%.

A simple procedure for the simultaneous determination of pseudouridine and creatinine in urine using ion-pair high-performance liquid chromatography with ultraviolet detection is described. It consists of simply diluting the filtered urine with mobile phase (1:20) followed by direct chromatographic injection. A single analysis takes only 10 min. This method has been applied to the analysis of urine samples from normal donors and patients with different types of cancer. The mean values, means, of the peak-area ratio of pseudouridine to creatinine were 61.79.10(-3) and 81.92.10(-3) for male and female normal donors, respectively. Out of twenty-five urine samples of patients with cancer examined, nineteen (all the forteen males included) had values higher than means + 2 sigma.

The determination of protein nitrogen in feeds and wheat by microcomputer controlled titration is described. The method involves direct titration of ammonia with standard hypochlorite titrant in the presence of bromide. The titrant is delivered by an automatic buret, and the microcomputer controlled, automatically computed potentiometric end points are precise to 0.1% over a 5-fold concentration range of nitrogen. Digestions performed with both mercury and copper catalysts show comparable results. Samples are weighed before digestion by an electronic balance interfaced to the computer which records sample number and weight. An automatic pipet aliquots, dilutes, and buffers samples directly from the digestion tubes; the samples can be immediately titrated with the automatic titrator. The results for protein in NBS standards and check feed samples from an offical testing program compare closely with average values reported for these standards. Results show that feed and wheat samples contained 10-100% protein. Precision for successive aliquots of the same digests is 0.1-0.4%relative standard deviation; precision for multiple digestions of the same sample is 0.1-0.8%.

Sunflower is a major oil seed crop worldwide, and it is also an important crop in Mediterranean areas where salinity is an increasing problem. In this paper, the effect of saline irrigation water on seed yield and quality of sunflower was evaluated. A pot experiment was carried out over two crop seasons on two hybrids -a standard one (Carlos) and a high oleic one (Tenor) - submitted to five salinity levels of irrigation water (0.6, 3, 6, 9 and 12 dS m -1 ). Soil salinity was monitored over the entire crop cycle, and leaf ion content was determined at maturity. Tenor showed higher Na + and Mg 2+ content but lower K + values. No difference between the two hybrids was observed for Cl - content. A progressive increase in leaf Na + , K + and Cl contents and Na + /K + ratio with increasing salinity level was observed. Seed weight per head, 1000 achene weight, number of seeds per plant and oil yield significantly decreased under salt stress in both hybrids. The percent seed yield decrease was higher per unit increase in electrical conductivity of irrigation water, ECw (8%), than per unit increase in electrical conductivity of saturated-soil extracts, ECe (5%). Concerning oil fatty acid composition, the main significant difference as result of salt stress was a progressive increase in oleic acid content, from 82.2% to 86.7% for Tenor and from 21.8% to 27.3% for Carlos, which was consistent with a decrease in linoleic acid content, from 5.9% to 3% for Tenor and from 66% to 61.3% for Carlos. These results confirm the possible inhibition of ole-ate desaturase under salt stress.