Quality Assessment of Bee Pollen-Honey Mixtures Using Thin-Layer Chromatography in Combination with Chemometrics.

The aim of this study is to develop a rapid, effect-directed screening method for quality assessment of bee pollen-honey mixtures. The comparative antioxidant potential and phenolic content of honey, bee pollen, and the bee pollen-honey mixtures, was performed using spectrophotometry. The total phenolic content and antioxidative activity of bee pollen-honey mixtures with 20 % bee pollen share were in the range 3.03-3.11 mg GAE/g, and 6.02-6.96 mmol TE/kg, respectively, while mixtures with 30 % bee pollen share contained 3.92-4.18 mg GAE/g, and 9.69-10.11 mmol TE/kg. Chromatographic fingerprint of bee pollen-honey mixtures was performed by high-performance thin-layer chromatography with conditions developed by authors and reported for the first time. Fingerprint analysis hyphenated with chemometrics enabled authenticity assessments of honey in mixtures. Results indicate that bee pollen-honey mixtures represent a food with highly, both, nutritious characteristics and health-promoting effect.

Authenticity assessment of cultivated berries via phenolic profiles of seeds.

Considering the health-benefits of berry fruits consumption and increased market demands for food authenticity as one of the most important quality assurances, phenolic profiling by high-performance thin layer chromatography and ultra-high-performance liquid chromatography hyphenated with mass spectrometry was combined with multivariate analysis for phytochemical characterization and intercultivar discrimination of cultivated berry seeds. The phenolic profiles of 45 berry seeds from nine genuine Serbian cultivated fruit species (strawberry, raspberry, blackberry, black currant, blueberry, gooseberry, cape gooseberry, chokeberry, and goji berry) revealed a good differentiation according to botanical origin. In order to determine biomarkers responsible for the classification, a total of 103 phenolic compounds were identified, including 53 phenolic acids and their derivatives, 26 flavonoids and 24 glycosides. Biomarkers derived from the phenolic profile of berry seeds proved to be a powerful tool in the authentication of botanical origin, and may be useful in detection of frauds in berry-based seed-containing product.

Quality Assessment of Apple and Grape Juices from Serbian and German Markets by Planar Chromatography-Chemometrics.

The high consumption of plant-based foods on a global scale has increased the number of adulterations in the food industry. Along with this, analytical approaches to fraud detection need to be further developed. A nontargeted effect-directed profiling by high-performance thin-layer chromatography hyphenated with five effect-directed assays (free radical scavenging assay, Aliivibrio fischeri bioassay, and acetylcholinesterase, butyrylcholinesterase, and tyrosinase inhibition assays) and multi-imaging provided additional information on the antioxidative, antimicrobial, and enzyme inhibition activities for 18 apple and 18 grape juices from markets in Serbia and Germany. Bioactive zones of interest were eluted using an elution head-based interface and further characterized by electrospray ionization high-resolution mass spectrometry. The different profiles were evaluated chemometrically, and several compounds, which were characteristic of samples from different markets located in Serbia and Germany, were identified in apple juice (such as chlorogenic acid, phloridzin, epicatechin, and caffeic acid) and grape juice (such as chlorogenic acid, epicatechin, and quercetin). The developed rapid and simple method for the quality assessment of fruit juices coming from different (geographic) markets showed clear quality differences. Thus, it could be used to learn more about quality differences, to detect fraud in fruit juice production, and to verify the authenticity of the origin.

Comprehensive electrophoretic profiling of proteins as a powerful tool for authenticity assessment of seeds of cultivated berry fruits.

Product authentication is one of the most important food quality assurances. Considering the importance of consumption of berry fruits with proven health-beneficial properties, high sensory values and rich composition in bioactive substances, the aim of this study was to evaluate a straightforward and simple procedure for the protein fingerprinting of berry seeds. For this purpose, protein profiles of 45 samples of genuine berry fruit cultivars (strawberry, raspberry, blackberry, black currant, blueberry, gooseberry, chokeberry, cape gooseberry, and gojiberry) were analyzed by SDS-PAGE electrophoresis in combination with advanced chemometric tools. The most important parameters for discrimination among berry seeds were polypeptides at 12.8; 15.1; 25.0; 26.4; 30.0; 41.8; 44.4; 46.0; 48.5; 52.3 and 56.4 kDa. Biomarkers obtained from the protein profile of berry seeds proved to be a powerful tool in the authentication of their botanical origin, as well as for potential detection of berry-based products adulteration.

Mineral Content as a Tool for the Assessment of Honey Authenticity.

The present work aims to provide a contribution to the overall investigation of European unifloral honeys with regard to authentication according to botanical and geographical origins. The mineral content of 206 monofloral honey samples of five botanical origins from six different regions in Serbia was investigated by inductively coupled plasma optical emission spectrometry. Chemometric techniques were applied for the classification and differentiation of acacia, sunflower, and linden honey according to botanical origin, as well as acacia honey samples according to regional origin. The highest influence on the differentiation of acacia honey samples was the presence of siderophile and chalcophile elements, whereas sunflower and linden honeys were determined by the presence of lithophile elements, indicating their origin from soil. However, due to the different bioaccumulation properties of plants, the presence of elements is not necessarily directly correlated to their presence in soil, which is confirmed by the results of the authentication of geographical origin of acacia honey.

Quality assessment of marketed chamomile tea products by a validated HPTLC method combined with multivariate analysis.

Chamomile tea composed of dried flower heads of Matricaria recutita L. (Asteraceae) is one of the most popular single ingredient herbal teas. Tea industries, spice shops or public bazaars are mostly supplied chamomile as a raw material via cultivation or through nature-picking. However, one of the drawbacks of nature-picking is adulteration. This could be either due to false authentication of the plant materials by ingenuous pickers or intentional/unintentional substitution with other flowers resembling to chamomile in appearance during harvesting. Therefore, quality control of raw chamomile materials before marketing should be carefully considered not only by quantification of apigenin 7-O-glucoside (active marker) but also by fingerprinting of chemical composition. This work presents both quantification of apigenin 7-O-glucoside and chemical fingerprinting of commercial chamomile tea products obtained from different food stores and spice shops by a validated HPTLC method. In addition, HPTLC profiles of investigated chamomile tea samples were compared with HPLC method stated in the European Pharmacopoeia and it was found that HPTLC method was superior to HPLC method in the field of adulteration confirmation. Therefore, fingerprint profiles performed on the silica gel 60 NH2 F254s HPTLC plates combined with pattern recognition techniques of these marketed products were comparatively evaluated with wild and cultivar chamomile samples and also chamomile-like species from Asteraceae. Consequently, not chamomile tea bags but crude flowers sold on market were found to be adulterated with other plant materials.

TLC Fingerprinting and Pattern Recognition Methods in the Assessment of Authenticity of Poplar-Type Propolis.

Propolis is a "natural" remedy with prominent biological activity, which is used as dietary supplement. In the absence of clinical studies that would substantiate these claims, information on the biological activity of propolis is valuable. This study comprises chromatographic, image processing and chemometric approach for phenolic profiling of Serbian, Croatian and Slovenian propolis test solutions. Modern thin-layer chromatography equipment in combination with software for image processing was applied for fingerprinting and data acquisition, whereas the principal component analysis was used as pattern recognition method. Characterization of phenolic profile was performed along with the determination of the botanical and geographical origin of propolis. High-performance thin-layer chromatograms reveal that Central and Southeastern European propolis samples are rich in flavonoids. In addition, phenolic compounds proved to be suitable markers for the determination of European propolis authenticity.

Modern analytical techniques in the assessment of the authenticity of Serbian honey.

Food authenticity in a broader sense means fulfilling chemical and physical criteria prescribed by the proposed legislation. In the case of honey authenticity, two aspects are of major concern: the manufacturing process and the labelling of final products in terms of their geographical and botanical origin. A reliable assessment of honey authenticity has been a longterm preoccupation of chemists-analysts and it usually involves the use of several criteria and chemical markers, as well as a combination of analytical and statistical (chemometric) methods. This paper provides an overview of different criteria and modern methods for the assessment of honey authenticity in the case of a statistically significant number of authentic honey samples of several botanical types from various regions of Serbia.

Lipophilicity assessment of ruthenium(II)-arene complexes by the means of reversed-phase thin-layer chromatography and DFT calculations.

The lipophilicity of ten ruthenium(II)-arene complexes was assessed by reversed-phase thin-layer chromatography (RP-TLC) on octadecyl silica stationary phase. The binary solvent systems composed of water and acetonitrile were used as mobile phase in order to determine chromatographic descriptors for lipophilicity estimation. Octanol-water partition coefficient, logK(OW), of tested complexes was experimentally determined using twenty-eight standard solutes which were analyzed under the same chromatographic conditions as target substances. In addition, ab initio density functional theory (DFT) computational approach was employed to calculate logK(OW) values from the differences in Gibbs' free solvation energies of the solute transfer from n-octanol to water. A good overall agreement between DFT calculated and experimentally determined logK(OW) values was established (R(2) = 0.8024-0.9658).