Marietta Fodor

Zirconium induced physiological alterations in wheat seedlings

The effects of zirconium ascorbate (Zr-ASC), a water-soluble complex of Zr, were examined on wheat seedlings (Triticum aestivum L. cv. MV. 20). Hydroponically grown plants were exposed to 10, 33, 55, 100 and 550 µM Zr-ASC (Zr10, Zr33etc.). After 9 d of treatment inhibition of germination, retarded root and shoot growth, and increased activities of antioxidant enzymes (guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase) showed that Zr-ASC was only harmful at and over a concentration limit of 100 µM. Chlorophyll (Chl) content of plants was only decreased by Zr550. Zr-ASC at lower concentrations was beneficial for plant development: Zr10 and Zr33 enhanced root elongation, Zr55 induced about 30 % increase in the total Chl content, while the activity of antioxidant enzymes was not elevated indicating that no oxidative stress was generated by the intracellularly accumulated Zr4+ ions.

Quantitative determination of coenzyme Q10 from dietary supplements by FT-NIR spectroscopy and statistical analysis

A novel, time- and money-sparing method has been developed and validated for the quantitative determination of coenzyme Q10 (CoQ10) from several dietary supplements. FT-NIR spectroscopy was applied for the examination, and a calibration model was built by partial least-square regression (PLS-R) using 50 dietary supplements. The combination of FT-NIRS and multivariate calibration methods is a very fast and simple way to replace the commonly used HPLC-UV method; because in contrast with the traditional techniques, sample pretreatment and reagents are not required and no wastes are produced. The calibration models could be improved by different variable selection techniques (for instance interval PLS, interval selectivity ratio, genetic algorithm), which are very fast and user-friendly. The R2 (goodness of calibration) and Q2 (goodness of validation) of the variable selected models are highly increased, the R2 values being over 0.90 and the Q2 values being over 0.86 in every case. Fivefold cross-validation and external validation were applied. The developed method(s) could be used by quality assurance laboratories for routine measurement of coenzyme Q10 products.

Comparison of antioxidant capacity assays with chemometric methods

Seven antioxidant capacity assays were compared and evaluated (ranked and grouped) using several statistical methods. The aim of the research was to compare the results of different antioxidant capacity assays and choose preferably one (or two) method(s), which could reproduce on its own the consensus results of all of the others. The two datasets (berries and sour cherries) gave quite similar results. Cluster analysis and principal component analysis could point out the methods that are most similar and best connected to each other. Not only are the groupings of the methods novel in this study but also the application of sum of ranking differences (SRD) and the generalized pair correlation method (GPCM) to compare and rank the various antioxidant capacity assays independently. In the case of berry samples, ferric ion reducing antioxidant power assay (FRAP) was the most successful as demonstrated by the results of SRD and GPCM. Moreover, GPCM (with conditional exact Fishers test and probability weighted ordering) could distinguish between 2,2-diphenyl-1-picrylhydrazyl free radical scavenging (DPPH) and lipid soluble antioxidant capacity (ACL) methods, which was not revealed by the SRD procedure. In the case of sour cherry samples the total polyphenolic content (TPC) was the most appropriate method and FRAP was the second to replace all the other assays. GPCM could differentiate between FRAP and trolox equivalent antioxidant capacity (TEAC) methods. The suggested techniques were FRAP and TPC for both datasets to replace all the others, whereas the ACL and water soluble antioxidant capacity (ACW) techniques give extremely distant results.

EFFECT OF ZIRCONIUM TREATMENT ON WHEAT SEEDLINGS DEVELOPMENT, AMINO ACID COMPOSITION, AND BORON CONTENT

The effects of zirconium ascorbate (Zr-ASC) were examined on wheat seedlings (Triticum aestivum L. cv. ‘MV. 20’). Plants grown hydroponically for nine days were exposed to solutions having various concentrations of Zr-ASC. The investigated plants were able to take up the Zr-ASC complex, accumulation and translocation of the metal has also been observed. Translocation mechanisms seem to be working efficiently to a certain concentration limit where from the translocation between root and shoot is limited. An interesting phenomenon was noticed in the case of boron, namely that the concentration change tendencies of boron and Zr were similar. A significant change was observed in the case of amino acid content, the total amino acid content increase was pronounced both in roots and shoots.