Applicability of ultra performance convergence chromatography, a new generation of supercritical fluid chromatography, for the analysis of pesticide residues

Monitoring and controlling wide variety of pesticide residues is a crucial challenge of food safety. In our study ultra-performance convergent chromatography (UPC2), as the new generation of supercritical fluid chromatography coupled with ESI-MS/MS system was applied to separate a set of pesticides to investigate their chromatographic behavior under various UPC2 conditions. 30 components were selected representing the GC and LC measurable components. Capacity factors obtained from LC and GC runs UPC2-PDA were compared. Based on our data UPC2 should be considered as an alternative chromatographic approach with separation mechanisms not yet fully characterized. Interestingly the type of mobile phase modifier influences the ionization in an ESI-MS system

Structure of the adsorption layer of various ionic and non-ionic surfactants at the free water surface, as seen from computer simulation and ITIM analysis

Molecular dynamics simulations of the adsorption layer of five different surfactant molecules, namely pentanol, octanol, dodecanol, dodecyl trimethyl ammonium chloride, and sodium dodecyl sulphate have been performed at the free surface of water at two different surface densities, namely 1 μmol/m2 (corresponding to unsaturated adsorption layer), and 4 μmol/m2 (corresponding to saturated adsorption layer), on the canonical ensemble at room temperature. The surfactants have been chosen in such a way that the effect of their headgroup charge as well as alkyl tail length on the properties of the adsorption layer can be separately investigated. The results are analysed in terms of the molecular level structure of the adsorption layer; organisation of the different groups and molecules along the macroscopic surface normal axis as well as conformation and orientation of the apolar tail is investigated in detail. In addition, the roughness of the surface of the aqueous phase is also analysed, using the ITIM method for accurately locating the real, capillary wave corrugated surface of the aqueous phase. © 2014 Elsevier B.V. All rights reserved

Effects of food processing technology on valuable compounds in elderberry (Sambucus nigra L.) varieties

Elderberry (Sambucus nigra L.) is a potential source of natural food colorants because of its high anthocyanin content. The aim of this work is to reveal which technology step has effect on the valuable components (total anthocyanins, total polyphenols) and on the color parameters in elderberry and in this regard to determine possible differences between elderberry varieties. Based on experiment results concentrate production steps have great effects on the studied parameters in case of two varieties especially in the heating and microfiltration steps but in different ratio. Polyphenolic compounds in ‘Samocco’ are more stable during the juice production than ‘Haschberg’. Color stability test revealed that in case of colored samples ‘Samocco’ had stronger color intensity in the foods/ models. These differences should be taken into account when selecting a certain variety for industrial utilization

Genistein isoflavone glycoconjugates in sour cherry cultivars : Prunus cerasus L.

Although the isoflavone genistein has well-established health-beneficial effects, it is not a major component of Western diet, since soy consumption, the main dietary source of genistein, is low in these populations. Genistein compounds were studied in twelve commercial sour cherry (Prunus cerasus L.) cultivars grown in Hungary. High performance liquid chromatography coupled to quadrupole/time-of-flight mass spectrometry, equipped with electrospray ion source (HPLC-ESI-qTOFMS) was used for screening and confirmatory analyses. Genistin and genistein were found in some Hungarian native sour cherry cultivars including ‘Pipacs1’, ‘Kántorjánosi’, ‘Debreceni bőtermő’ and ‘Éva’. Genistein content in fruits of the latter three cultivars ranged between 0.4 to 0.6 mg, while in ‘Pipacs1’ a total of 4.4 mg genistein compounds (expressed as aglycone equivalents per 100 g of fresh fruit) was determined. These cultivars may play an important role as complementary genistein sources in the Western diet. Especially ‘Pipacs 1’, may be best utilized in functional food products

Seasonal Variation in Phenolic Content and Antioxidant Activity of Glechoma Hederacea L. Harvested from Six Hungarian Populations

Ground ivy (Glechoma hederacea L.) is one of the prosperous plants for the food-industry as natural antioxidant. This fact led us to examine the chemical diversity of six ground ivy populations situated in different natural habitats and to analyse the effect of the harvesting time. Total phenolic content, chlorogenic acid, and rutin content, as well as the antioxidant capacity showed significant differences due to the harvest time. The highest total phenol content (115 mg g–1 GAE) and the strongest antioxidant activity (53.3 mg g–1 AAE) were measured in the population originated from Budapest (GLE 6), harvested in July. The highest chlorogenic acid (357 mg/100 g) and rutin (950 mg/100 g) contents were detected in the July harvested samples from the Soroksár Botanical Garden population (GLE 1). According to our results, the collection time has significant effect on the total phenolic content – first of all on the chlorogenic acid and rutin accumulation levels of ground ivy, while the influence of the habitat seems to be less important