Potential application of green extracts rich in phenolics for innovative functional foods: natural deep eutectic solvents as media for isolation of biocompounds from berries.

The health-promoting effects of berries have attracted attention due to the possible application of their extracts as functional ingredients in food products. Natural deep eutectic solvents (NADESs) are a new generation of environmentally friendly solvents for the extraction of natural products, and they are green alternatives to organic solvents, and they can improve the solubility, stability, and bioavailability of isolated biocompounds. In this study, an efficient eco-friendly method was used for the extraction of phenolic compounds from different berries: chokeberries, blueberries, and black goji berries with a range of eutectic solvents consisting of hydrogen bond acceptors (HBAs) such as choline chloride, L-proline, L-glycine, and L-lysine and hydrogen bond donors (HBDs) such as malic, citric, tartaric, lactic and succinic acids, glucose and glycerol. The obtained results indicated the ability of NADESs towards selective extraction of phenolics; the eutectic system choline chloride : malic acid showed selective extraction of anthocyanins, while choline chloride : glycerol and choline chloride : urea showed selectivity towards flavonoids and phenolic acids. The methodology for screening of the NADES extraction performance, which included chromatographic profiling via high-performance thin layer chromatography combined with chemometrics and spectrophotometric essays, allowed effective assessment of optimal eutectic solvents for isolation of different groups of phenolics. Great antioxidant and antimicrobial activities of extracts, along with the green nature of eutectic solvents, enable NADES berry extracts to be used as "green-labelled" functional foods or ingredients.

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.

Thin-layer chromatography in the authenticity testing of bee-products.

Quality control, nutritional value and the monitoring of hazardous residues in honey bee- products have become major topics for both producers and consumers. Due to its potential role in human health, bee-products rich in bioactive compounds are becoming increasingly popular. This review aims to provide an overview of thin-layer chromatography methods used in quality control,authenticity testing and chemical profiling of bee-products in order to help scientists engaged in the field of bee-products chemistry to utilize the advantages of this technique in the detection and elimination of fraudulent practices in bee-product manufacturing. Recently, hyphenation of thin-layer chromatography, image analysis and chemometrics support bee-products analysisbysimultaneousdeterminationofanalytes with different detection principles, identification of individual bioactive compounds as well as structure elucidation of compounds. Highlighted opportunities of thin-layer chromatography could encourage further investigations that would lead to improvements in the detection and elimination of marketing fraudulent practices.

Urban honey - the aspects of its safety.

To contribute to the development of urban beekeeping, we designed this study to obtain more information about the contamination of urban bee products with toxic metals, polycyclic aromatic hydrocarbons (PAHs), and pesticides. The samples of honey (N=23), pollen (N=13), and floral nectar (N=6) were collected from the experimental stationary apiary of the Belgrade University Faculty of Agriculture located in centre of Zemun (a municipality of the Belgrade metropolitan area) in 2015 and 2016. Metals (Pb, Cd, As, Cu, Zn, Fe, Mn, Ni, Cr, and Hg) were determined with inductively coupled plasma quadrupole mass spectrometry (ICP-QMS). Polycyclic aromatic hydrocarbons (PAHs) were analysed with high-performance liquid chromatography with fluorescence detection (HPLC-FLD). Pesticides were analysed with gas chromatography - mass spectrometry (GC-MS). The honey samples were generally within the European and Serbian regulatory limits. The levels of all the 123 analysed pesticides were below the limit of quantification (LOQ). Regarding PAH levels in honey, the highest content was found for naphthalene. The elevated levels of Hg and Cr and of PAHs in the pollen samples indicated air pollution. Pesticide residues in pollen, however, were below the LOQ. In nectar, metal levels were relatively similar to those in honey. Our results suggest that the investigated urban honey meets the regulatory requirements for metals, PAHs, and pesticides and is therefore safe for consumption.

Polyphenols as Possible Markers of Botanical Origin of Honey.

In recent years, the botanical and geographical origin of food has become an important topic in the context of food quality and safety, as well as consumer protection, in accordance with international standards. Finding chemical markers, especially phytochemicals, characteristic for some kind of food is the subject of interest of a significant number of researchers in the world. This paper is focused on the use of polyphenols as potential markers for the determination of botanical origin of honey. It includes a review of the polyphenols present in various honey samples and the methods for their separation and identification. Special emphasis in this paper is placed on the identification of honey polyphenols using advanced LC-MS techniques in order to find specific markers of botanical origin of honey. In this regard, this study gives an overview of the literature that describes the use of LC-MS techniques for the isolation and determination of honey polyphenols. This review focuses on the research performed in the past two decades.

The polyphenolics and carbohydrates as indicators of botanical and geographical origin of Serbian autochthonous clones of red spice paprika.

Spice peppers (Capsicum annuum L.) var. Lemeska and Lakosnicka paprika were investigated to evaluate their polyphenolic and carbohydrate profiles and antioxidant activity. A total of forty-nine polyphenolics were identified using ultrahigh-performance liquid chromatography (UHPLC) coupled to LTQ OrbiTrap mass analyzer. Twenty-five of them were quantified using available standards, while the other compounds were confirmed by exact mass search of their deprotonated molecule [M-H](-) and its MS(4) fragmentation. Thirteen carbohydrates were quantified using high-performance anion exchange chromatography (HPAEC) with pulsed amperometric detection (PAD). Radical scavenging activity (RSA) ranged from 17.32 to 48.34mmol TE (Trolox equivalent)/kg DW (dry weight) and total phenolics content (TPC) was ranged between 7.03 and 14.92g GAE (gallic acid equivalents)/kg DW. To our best knowledge, five polyphenolic compounds were for the first time tentatively identified in paprika: 5-O-p-coumaroylquinic acid, luteolin 7-O-(2″-O-pentosyl-4″-O-hexosyl)hexoside, quercetin 3-O-(2″-O-hexosyl)rhamnoside, isorhamnetin 3-O-[6″-O-(5-hydroxyferuloyl)hexoside]-7-O-rhamnoside, and luteolin 7-O-[2″-O-(5'″-O-sinapoyl)pentosyl-6″-O-malonyl]hexoside.

Chemical composition of two different extracts of berries harvested in Serbia.

Total phenolic content (TPC), total anthocyanin content (TAC), free and total ellagic acid content, sugars, minerals, and radical-scavenging activity were determined in nine berries harvested in Serbia. More than 30 phenolic compounds were identified; among them, 11 polyphenols and cis,trans-abscisic acid were quantified using UHPLC coupled with an LTQ-Orbitrap XL mass analyzer. For the first time chrysin, naringenin, pinocembrin, and galangin were quantified in some of the investigated berry species. The extraction efficiency of the two extraction systems, methanol and acetone, was investigated. It was found that acetone is a better extracting solvent for TPC, whereas more TAC was extracted by methanol. TPC in acetone extracts ranged from 177.51 to 459.71 mg gallic acid equiv/100 g frozen weight. TAC ranged from 5.39 to 96.94 mg cyanidin-3-glucoside/100 g frozen weight in methanol extracts. The amounts of both free and total ellagic acid were found to be higher in the acetone extract in comparison to the methanol extract.

Determination of the soil-water partition coefficients (logK(OC)) of some mono- and poly-substituted phenols by reversed-phase thin-layer chromatography.

In order to determine the soil-water partition coefficient for eleven mono- and poly-substituted phenolic compounds, for which there is still no literature data available, the possibility of using thin-layer chromatography (TLC) as a means for rapid and reliable logK(OC) estimation was examined. A series of chromatographically derived descriptors: R(M)(0), b, C(0) and PC1 (first principal component), calculated from retention data obtained under reversed-phase conditions, were used for the assessment of models as well as for a direct calibration procedure. The final calibration models are discussed with regard to the achieved accuracy and statistical quality, the type of descriptors used and the corresponding chromatographic conditions. The estimated logK(OC) values of the studied phenols were compared with those obtained by other means: (a) the present OECD guideline based on an HPLC technique; (b) the KOCWIN software package, available free of charge from the US Environmental Protection Agency web site and (c) general LSER models established by Nguyen and coworkers, and Poole and coworkers. The proposed method showed the best agreement with the results obtained by the OECD procedure, followed by the LSER models of Poole and Nguyen. Lower quality correlations were achieved with the KOCWIN calculated values, especially those predicted by molecular connectivity indices.

Structure-retention relationship study of arylpiperazines by linear multivariate modeling.

A quantitative structure-retention relationship study has been performed to correlate the retention of 33 newly synthesized arylpiperazines with their molecular characteristics, using thin-layer chromatography. Principal component analysis followed by multiple linear regression (MLR), principal component regression (PCR) and partial least squares (PLS) was performed to identify the most important factors, to quantify their influences, and to select descriptors that best describe the behavior of the compounds investigated. The best statistical performance was achieved by applying PLS regression, leading to the lowest value of the standard error (root mean square errors of calibration of 0.159 and cross-validated value RMSE cross-validation=0.231 units), followed by the PCR (root mean square errors of calibration=0.195 and RMSE cross-validation=0.305) and MLR (R(adj)(2)=0.9499, F=102.017, mean square error=0.052 and predicted residual error sum of squares=2.23). Two factors of the highest influence: surface tension and hydrophilic-lipophilic balance appear as the part of obtained models. In addition, polar surface area and hydrophilic surface area are included by both PLS and PCR models. Moreover, logP has been added to the PLS model. Besides, PCR model includes following descriptors: hydrogen bond acceptor, hydrogen bond donor and LUMO energy, whereas topological descriptors: connectivity indices 0 and 2, and valence index 3 are included in the MLR model.