Influence of harvest date and crop yield on the fatty acid composition of virgin olive oils from cv. Picual

In this study was analyzed the effect of crop year and harvesting time on the fatty acid composition of cv. Picual virgin olive oil. The study was carried out during the fruit ripening period for three crop seasons. The mean fatty acid composition of Picual oils was determined. The oils contained palmitic acid (11.9%), oleic acid (79.3%), and linoleic acid (2.95%). The content of palmitic acid and saturated fatty acids decreased during fruit ripening while oleic and linoleic acids increased. The amount of stearic and linolenic acids decreased. The amount of saturated acids, palmitic and stearic, and the polyunsaturated acids linoleic and linolenic was dependent on the time of harvest, whereas the amount of oleic acid varied with the crop year. The differences observed between crop years for both palmitic and linoleic acid may be explained by the differences in the temperature during oil biosynthesis and by the amount of summer rainfall for oleic acid content. A significant relationship was observed between the MUFA/PUFA ratio and the oxidative stability measured by the Rancimat method.     

Analysis of virgin olive oil volatiles by a novel electronic nose based on a miniaturized SAW sensor array coupled with SPME enhanced headspace enrichment

A novel electronic nose based on solid-phase microextraction (SPME) coupled with a surface acoustic wave (SAW) sensor array has been used to analyze different quality virgin olive oils. A mathematical model was designed with 37 samples to distinguish lampante from the other virgin olive oils categories (extra-virgin and virgin), because lampante-virgin olive oils cannot be consumed without a previous refining process. The model, successfully validated with a test set of 16 samples, was able to classify 90% of the samples correctly. Misclassifications were explained by SPME-HRGC analyses and a second sensory evaluation.     

Recovery of pigments from Origanum majorana L. by extraction with supercritical carbon dioxide

Extraction of pigments (chlorophylls and carotenoids) from marjoram (Origanum majorana L.) with supercritical carbon dioxide was investigated. The aim of this study was to map the effects of extraction pressure and temperature on the yield of coloring materials by applying a 3(2) full factorial design with three repeated tests in the center of the design. For comparison, laboratory and pilot plant Soxhlet extractions were carried out using ethanol and n-hexane solvents. The compositions of pigments in marjoram extracts were determined by HPLC. Similar amounts of carotenoids, in addition to 40% of chlorophylls and their derivatives, were recovered from the supercritical fluid extraction, in comparison to the ethanol Soxhlet extraction.     

Subcellular localization and isoenzyme pattern of peroxidase and polyphenol oxidase in beet root (Beta vulgaris L.)

The two enzymes involved in enzymatic browning reactions, polyphenol oxidase (PPO) and peroxidase (PO), have been partially purified and extracted from different fractions of beet root. PPO is mainly located in the membrane fraction, and it was also found in the soluble fraction. In both cases PPO was in its latent state. However, PO activity was higher in the soluble fraction than in the membrane fraction. Nevertheless, the highest values of specific activity for PO were obtained from the solubilized enzyme from acetone powders. Under native isoelectric focusing (IEF), several PPO isoenzymes were present in the pH range of 4.8-5.8. All of these isoenzymes shared a single band with a similar apparent mass under sodium dodecyl sulfate-polyacrylamide gel electrophoresis. PO was also analyzed by IEF, showing a complex isoenzyme pattern in all fractions. The characteristic basic PO isoenzyme of high pI found in both the soluble fraction and the solubilized enzyme from acetone powders was not detected in the membrane fraction. The kinetic characterization of PPO and PO from all fractions was carried out.     

Degradation of lignin in wheat straw during growth of the oyster mushroom (Pleurotus ostreatus) using off-line thermochemolysis with tetramethylammonium hydroxide and solid-state (13)C NMR.

The oyster mushroom (Pleurotus ostreatus) is widely cultivated on wheat straw (Triticum aestivum); however, there is a need to better understand the relationship between the chemical composition of the compost and mushroom growth. Wheat straw was degraded over a period of 63 days by P. ostreatus during which time it was sampled at weekly intervals. Off-line thermochemolysis with tetramethylammonium hydroxide and solid-state (13)C NMR were then used in the molecular characterization of the undegraded wheat straw and the degraded samples. The degraded wheat straw samples had a lower proportion of syringyl- to guaiacyl-derived moieties and cinnamyl- to guaiacyl-derived moieties than the undegraded control. There were increases in both guaiacyl and syringyl acid to aldehyde ratios with composting time, which showed that side-chain oxidation has been mediated by P. ostreatus. The (13)C NMR spectra confirmed the increase in carboxyl content but indicated that the overall lignin and methoxyl contents remained relatively constant, although some nonsystematic variations were observed. The spectra also showed a decrease in amorphous noncellulosic polysaccharides in relation to the crystalline cellulose upon degradation.     

Factors affecting the caffeine and polyphenol contents of black and green tea infusions.

The effects of product and preparation variables on the in-cup chemical composition of tea extracts is of interest because the appearance and taste characteristics and the possible health effects of a tea liquor arise from the chemical components extracted from the leaf during tea preparation. A comprehensive study was therefore undertaken to determine the contributions of product and preparation variables on the total soluble solids, caffeine, and polyphenol contents of tea extracts. The results of this study show that the variety, growing environment, manufacturing conditions, and grade (particle size) of the tea leaves each influence the tea leaf and final infusion compositions. In addition, the composition of the tea infusion was shown to be influenced by whether the tea was contained in a teabag and, if so, the size and material of construction of the bag. Finally, the preparation method, including the amounts of tea and water used, infusion time, and amount of agitation, was shown to be a major determinant of the component concentrations of tea beverages as consumed. An illustration of the variation introduced by these product and preparation factors is provided by comparing solids, caffeine, and polyphenol contents of green and black tea infusions when commercial products are prepared according to the instructions given on their packaging.     

Effects of tetracycline administration on the proteomic profile of pig muscle samples (L. dorsi)

Effect of tetracycline (TC) administration on the proteomic profile of pig muscle was evaluated by 2D electrophoresis and MALDI-TOF mass spectrometry. The TC content at slaughter was determined in L. dorsi samples by HPLC-DAD. Mean residual concentration of TC in the muscle of treated animals, calculated as the sum of TC and epi-TC was 126.3 microg/kg, indicating a rapid elimination of TC in this tissue. Several differential spots (n = 54, p < 0.05) were observed in protein profiles from control and treated animals. MALDI-TOF identification gave a positive match for 5 differential spots, that is, glycerol-3-phosphate dehydrogenase 1 (G3PD1), phosphoglycerate kinase 1, novelprotein (0610037L13Rik), leucine aminopeptidase 3 (LAP), and hypothetical protein isoform 2. Results show that proteomics could be a useful tool to reveal pharmacological treatments with TC, even if the possible uses of differential spots as biomarkers to detect illegal administration of TC require further studies. Different spot patterns as a consequence of TC treatments seem to be another interesting issue for the consequences on tissue metabolism and meat quality.     

The use of lysimeter data for the test of two soil–water balance models: A case study

Two soil–water balance models were tested by a comparison of simulated with measured daily rates of actual evapotranspiration, soil water storage, groundwater recharge, and capillary rise. These rates were obtained from twelve weighable lysimeters with three different soils and two different lower boundary conditions for the time period from January 1, 1996 to December 31, 1998. In that period, grass vegetation was grown on all lysimeters. These lysimeters are located in Berlin‐Dahlem, Germany. One model calculated the soil water balance using the Richards equation. The other one used a capacitance approach. Both models used the same modified Penman formula for the estimation of potential evapotranspiration and the same simple empirical vegetation model for the calculation of transpiration, interception, and evaporation. The comparisons of simulated with measured model outputs were analyzed using the modeling‐efficiency index IA and the root mean squared error RMSE. At some lysimeters, the uncalibrated application of both models led to an underestimation of cumulative and annual rates of groundwater recharge and capillary rise, despite a good simulation quality in terms of IA and RMSE. A calibration of soil‐hydraulic and vegetation parameters such as maximum rooting depth resulted in a better fit between simulated and observed cumulative and annual rates of groundwater recharge and capillary rise, but in some cases also decreased the simulation quality of both models in terms of IA and RMSE. The results of this calibration indicated that, in addition to a precise determination of the soil water‐retention functions, vegetation parameters such as rooting depth should also be observed. Without such information, the rooting depth is a calibration parameter. However, in some cases, the uncalibrated application of both models also led to an acceptable fit between measured and simulated model outputs.     

Extinction and ecosystem function in the marine benthos

Rapid changes in biodiversity are occurring globally, yet the ecological impacts of diversity loss are poorly understood. Here we use data from marine invertebrate communities to parameterize models that predict how extinctions will affect sediment bioturbation, a process vital to the persistence of aquatic communities. We show that species extinction is generally expected to reduce bioturbation, but the magnitude of reduction depends on how the functional traits of individual species covary with their risk of extinction. As a result, the particular cause of extinction and the order in which species are lost ultimately govern the ecosystem-level consequences of biodiversity loss.