Survey for co-occurrence of ochratoxin A and aflatoxin B1 in dried figs in Turkey by using a single laboratory-validated alkaline extraction method for ochratoxin A

A survey was carried out to determine the co-occurrence of ochratoxin A and aflatoxin B1 in dried figs from Turkey. Samples from two seasons of crops (2003 and 2004) intended for export to the European Union and the 2004 crop obtained from the domestic Turkish market were analyzed. Affinity column cleanup methods were employed for determining separately ochratoxin A and aflatoxin B1, but for ochratoxin A an alkaline extraction procedure was employed (in contrast to the conventionally employed acidic extraction), which gave consistently higher toxin recovery. In-house validation of the ochratoxin A method gave a limit of detection of 0.15 ng/g and a limit of quantification of 0.5 ng/g with a repeatability of 5.8% in the range 5 to 10 ng/g (with a mean recovery of 94% for spiked samples). Positive results for ochratoxin A were confirmed by liquid chromatography-mass spectrometry. For the 2003 export figs (58 samples), 7 samples contained only aflatoxin B1, 2 samples contained only ochratoxin A, and 2 samples contained both toxins (with maximum concentrations of 35.1 ng/g for aflatoxin B1 and 13.0 ng/g for ochratoxin A). Similarly for the 2004 export figs (41 samples), 16 samples contained only aflatoxin B1, 4 samples contained only ochratoxin A, and 2 samples contained both toxins (with maximum concentrations of 20.6 ng/g for aflatoxin B1 and 26.3 ng/g for ochratoxin A). Of 20 retail samples of dried figs from Turkey, only one sample contained ochratoxin A (2.0 ng/g) and none were contaminated with aflatoxin B1. This survey revealed a 14 to 15% incidence of occurrence of ochratoxin A for 2 years, which is higher than previously reported.     

Pappus and fruit micromorphology and fruit anatomy in some members of the tribe Cardueae (Asteraceae) from Turkey with their contributions to systematics

The present investigation aims to determine pappus and fruit characters of 21 taxa representing 12 different genera from Turkey. For this reason, present data of pappus and cypsela characters as well as previous results from 21 additional Cardueae taxa have been comparatively evaluated, and a total of 42 taxa were grouped by using cluster and MDS analysis methods. The cluster analysis resolved two main clusters, with five taxa having scale or coroniform pappus as the first-branching group. Considerable variations were observed in the surface sculpture, and the pericarp and testa anatomical structures as well as the pappus characteristics. On the basis of fruit surface sculpture, four major types and two subtypes of ornamentation patterns were discerned, and based on their anatomies three types of testa epidermal structure were recognized. Our results show that Centaurea s.l. taxa do not exhibit clear distinction from the genus level; in some cases the taxa are separated to some extent, in other cases they are combined with Cyanus and Psephellus taxa. Two Klasea species with sclerenchymatous mesocarp exhibit the closest relationship to Centaurea s.l. taxa. Rhaponticum repens displays the nearest neighborhood with Centaurea s.l. and Klasea taxa. A diagnostic key based on the examined characteristics has been given. The taxonomic importance and systematic implications of the results are discussed in the light of the current framework. The evaluated cypsela and pappus characters are useful not only in assessing relationships within this group but also in delimiting genera and species.     

Energy and exergy analysis of a PV-T integrated ethanol PEM electrolyzer

A photovoltaic-thermal (PV-T) integrated ethanol proton exchange membrane electrolyzer (PEME) was proposed as a low-energy consuming energy storage option for renewable-sourced electricity as well as a way for simultaneous chemical production in this study. Energy and exergy analyses were applied to each component of the system (e.g., pumps, heat exchanger, PV-T, PEME, and separation unit (SPU)) and the whole system to assess the system performance. The mathematical modelling of the whole system along with its main components except for the SPU was done using the Engineering Equation Solver (EES) software package while the SPU was modelled through the ASPEN Plus. A detailed modelling of the PEME was also included. The effects of the PV-T and PEME parameters on energy and exergy efficiencies of the system were evaluated while the improvement potentials and scale up options were discussed. Energy and exergy efficiencies of the proposed system at the optimum operation of the PEME and under average climatic conditions in the city of Izmir, Turkey were determined to be 27.8% and 3.1%, respectively. Energy and exergy efficiencies of the system were mainly regulated by the PV-T and PEME, whose energy and exergy efficiencies were 40.6%, 56.6% and 13.8%, 14.1%, respectively. Effective PEME parameters for energy and exergy efficiencies of the system were membrane conductivity, membrane thickness, anode catalyst and the operation temperature of the PEME. By changing the PV-T and PEME parameters and by scale-up, energy and exergy efficiencies of the system could be improved.