•Chemical characterization and biological activity of 7 honey types was evaluated.•Honeydew honeys have significant antioxidant activity.•All tested honeys exhibited antibacterial activity.•Botanical ...and geographical origin are crucial for elemental composition.
A chemical characterization and biological activity of 7 honey types (multifloral, linden, rapeseed, sunflower, phacelia, acacia and honeydew honey) from different regions of Serbia were presented. The physicochemical characteristics, mineral content, antioxidant and antimicrobial activity were estimated and discussed. All honeys showed good nutritional characteristics, according to the adopted criteria of the standard codex for honey. The concentrations of 15 elements in honey samples were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). Limits of quantification were in the range from 0.003 mg/kg (Cd, Cr, Cu, Mn, and Pb) to 1.50 mg/kg for sodium. Precision was expressed as relative standard deviation and its values were lower than 1.50%. Accuracy was evaluated with certified reference material (fish protein, DORM 4, NRC and cooking chocolate, SRM 2384, NIST) and obtained recovery percentages were 71-127%. The content of the most abundant elements (K, Mg, and Na) and microelements (Al, Cu, Fe, Mn, Ni, Se, Si, and Zn) showed a significant variability in accordance of their botanical and geographical origin, but also the influence of harvest conditions. The levels of toxic metals (As, Cd, Cr, and Pb) are much lower than the maximal allowed for these metals according to European Commission Regulation. The antioxidant activity was evaluated by DPPH (Diphenylpicrylhydrazyl) assay while antimicrobial activity against Gram positive and Gram negative bacteria (E. coli and S. aureus) and fungi Candidi albicans was estimated by microdilution assay. The free radical scavenging assay (%RSA) varies significantly among the honey samples. The highest antioxidant activity was observed with honeydew honeys (over 75% RSA) and the lowest was observed in the acacia, ranging from 22.96 to 24.57% RSA. All honeys tested in this study exhibited antibacterial activity, with inhibition of bacterial growth, generally the higher against E. coli (80% for linden honeys) than against S. aureus (mostly much lower than 50%). Activity against Candidi albicans was almost negligible. The dataset composed of all experimental results was subjected to a chemometric evaluation and cluster analysis as hierarchical nonsupervised method was applied. According to the obtained outcome of applied algorithms, both botanical and geographical origin have important role in the elemental composition, antioxidant and antimicrobial activities.
This study utilized a facile one-pot protocol to synthesize Ni-cobalt zeolitic imidazolate framework (Ni-ZIF-67) nanocomposite, which was then characterized by Fourier transform infrared ...spectroscopy, X-ray diffraction, energy dispersive X-ray spectroscopy and scanning electron microscopy. The Ni-ZIF-67 nanocomposite was subsequently applied to modify a screen-printed electrode (SPE) as a durable sensor for detection of Sudan I concomitantly with bisphenol A (BPA), with remarkably increased electrochemical response when comparing with a bare SPE. The results showed the calibration plot to be linear in the concentration range between 0.03 μM and 535.0 μM, with a narrow limit of detection of 9.0 nM (S/N = 3). Our proposed protocol was successful in detecting target analytes in real tap water and food specimens.
In this work, Ni-ZIF-67 nanocomposite were synthesized by a simple method. The as-prepared Ni-ZIF-67 nanocomposite directly modified screen-printed electrode for the fabrication of Ni-ZIF-67/SPE sensor. Finally, the Ni-ZIF-67/SPE electrochemical sensor were used for concurrently detection of Sudan I and BPA by voltammetry methods. The novelty of the present work relates to the role of Ni-ZIF-67 nanocomposite that for the first time is employed in simultaneous determination of Sudan I and BPA with a high catalytic action to separate the anodic peaks of Sudan I and BPA.
•Ni-ZIF-67 nanocomposite was synthesized and characterized.•Modified electrode involve Ni-ZIF-67 nanocomposite were used for simultaneous determination of sudan I and bisphenol A.•Wide linear dynamic range (0.03–535.0 μM) and LOD of 9.0 nM were obtained.•The suggested method was successfully applied for sudan I detection in real sample.
Mycotoxins are toxic secondary metabolites of fungi that spoil food, and severely impact human health (e.g., causing cancer). Therefore, the rapid determination of mycotoxin contamination including ...deoxynivalenol and aflatoxin B
in food and feed samples is of prime interest for commodity importers and processors. While chromatography-based techniques are well established in laboratory environments, only very few (i.e., mostly immunochemical) techniques exist enabling direct on-site analysis for traders and manufacturers. In this study, we present MYCOSPEC - an innovative approach for spectroscopic mycotoxin contamination analysis at EU regulatory limits for the first time utilizing mid-infrared tunable quantum cascade laser (QCL) spectroscopy. This analysis technique facilitates on-site mycotoxin analysis by combining QCL technology with GaAs/AlGaAs thin-film waveguides. Multivariate data mining strategies (i.e., principal component analysis) enabled the classification of deoxynivalenol-contaminated maize and wheat samples, and of aflatoxin B
affected peanuts at EU regulatory limits of 1250 μg kg
and 8 μg kg
, respectively.
•Highly catalytic N-doped carbon dots (N-CDs) were prepared by microwave irradiation.•The N-CDs catalytic nano-reaction was utilized to amplify SERS signal.•The N-CDs nanocatalytic reaction was ...coupled with the affinity reaction.•A highly sensitive and selective SERS quantitative method was developed for biotin.
Highly catalytic and stable N-doped carbon dots (N-CDs) were prepared rapidly by microwave procedure using glucose as precursor and ammonium sulfite as N-dopant. The reduction of AgNO3 by trisodium citrate (TCA) was slow to form nanosilver (AgNP), and the N-CDs exhibited strong catalysis of the AgNP reaction. The formed AgNPs were used as indicator in the presence of Vitoria blue B (VBB) molecule probe with a SERS peak at 1615 cm−1. With the increase of nancatalyst N-CDs concentration, the AgNP reaction speed up, and the SERS peak of VBB enhanced linearly due to formation of more AgNPs as substrate. In the presence of avidin (Ad), the SERS peak weakened. Upon addition of biotin, the SERS peak enhanced due to turn on the indicator nanoreaction. The enhanced SERS signal had a good linear relationship with the biotin concentration in range of 0.0006–0.021 ng/mL, with a detection limit of 0.3 pg/mL.
•CAF was enriched with Fe3O4 coated MWCNTs sorbent.•Magnetic solid phase microextraction coupled with electrochemical detection.•New analytical method integrated with two miniaturised systems.•CAF ...concentrations in the micro volume of samples were determined.
In the current study, we introduce magnetic solid phase microextraction coupled with electrochemical detection of caffeine. A commercially available disposable screen-printed carbon electrodes modified with poly Alizarin Red S are employed as electrochemical sensors in the detection stage. However, the suitability of magnetic solid phase microextraction for electroanalytical methods such as square wave voltammetry has not been declared. With our optimised conditions in hand, the system response was linearly proportional to the concentration of caffeine in the range of 0.5–20µM with a correlation coefficient of about 0.9987. The detection limit of the sensing system was found to be 0.05µM (a signal-to-noise ratio of 3). At the end of the study, the suitability of this new procedure for the analysis of energy drink, soft drink, and chocolate milk samples was demonstrated.
•The latest research insight into mushroom glucan is presented.•Purification and quantification of mushroom β-glucan is summarized.•Physicochemical properties of mushroom β-glucan are ...presented.•Biological activities of mushroom β-glucan are reviewed.
One of the main active components from mushrooms was recently identified as β-glucan. Health-promoting β-glucans are an auspicious group of polysaccharides. β-Glucans from different sources such as cereals, yeast and grass have previously been documented. However, information on mushroom β-glucan is limited. This review summarizes the extraction, purification, quantification, and structural characterization of β-glucans, along with chemical and biological activities from this compound from mushrooms, and the current status of this research area with a view for future directions.
The aim of this study was to assess the ability of electronic tongue system TS-5000Z to evaluate meat quality based on flavor assessment, recognition and correlation with the meat chemical ...composition. Meat was sampled from eighteen beef cattle including 6 Wagyu breed cattle, 6 Angus breed cattle and 6 Simmental breed cattle. Chemical composition including dry matter, crude protein, fat, ash, cholesterol and taurine and flavor of the meat were measured. The results showed that different breed cattle had different chemical compositions and flavor, which contains sourness, umami, saltiness, bitterness, astringency, aftertaste from astringency, aftertaste from bitterness and aftertaste from umami, respectively. A principal component analysis (PCA) showed an easily visible separation between different breeds of cattle and indicated that TS-5000Z made a rapid identification of different breeds of cattle. In addition, TS-5000Z seemed to be used to predict the chemical composition according to its correlation with the flavor. In conclusion, TS-5000Z would be used as a rapid analytical tool to evaluate the beef quality both qualitatively and quantitatively, based on flavor assessment, recognition and chemical composition according to its correlation with flavor.
Fresh tea leaves (Camellia sinensis (L.) O. Kuntze) are processed by various techniques to produce different types of tea. The most common way to classify tea types is based on the similarities in ...processing methods resulting in the five commonly recognized tea types: white, green, oolong, black, and pu‐erh teas. The differences in the degree and nature of fermentation of tea leaves lead to different chemical changes depending on the processing method. Understanding the phytochemical profile of differently processed tea is important, as tea types classified by processing methods are currently not well defined because the chemical parameters for these tea types are still not established. Therefore, any significant characteristics found for a tea type due to processing may be helpful in defining tea types. However, the evidence on the impact of tea processing on phytochemical profile and contents in differently processed tea is currently unclear. Therefore, this review aims to examine (1) the processing techniques of white, green, oolong, black, and pu‐erh tea, (2) the impact of tea processing on tea phytochemicals, and (3) the key characteristics associated with the phytochemical profiles of differently processed tea.
Practical Application
Tea (Camellia sinensis (L.) O. Kuntz) is the most widely consumed beverage in the world. Tea consumption has been demonstrated through in‐vitro experiments and in animal and human intervention studies to exhibit potential in preventing various oxidative stress‐related chronic diseases, such as cardiovascular diseases, Alzheimer.s disease, diabetes and certain cancers. Based on the processing methods, tea is commonly categorized into white, green, oolong, black and pu‐er tea. However, there are large overlap in processing methods between some teas and, more importantly, the chemical compositions of differently processed teas are highly variable. This review aims to examine (1) how white, green, oolong, black and Pu‐erh tea are processed, (2) what are the effects of tea processing on tea phytochemicals and (3) to identify whether there are key characteristics associated to the phytochemical profiles of differently processed teas. The review will contribute to tea research in collating in one article the state of knowledge on the chemical changes and composition of the differently processed teas, and point to future direction in this area of research.
•Development and validation of a qualitative screening method for pesticides.•Investigations why the validation criteria were not fulfilled for many analytes.•Matrix effects affect analytes with ...similar retention times in a different way.•In-source collision induced dissociation attenuates signal intensities and provides additional criteria for identification.
Because of the high number of possible pesticide residues and their chemical complexity, it is necessary to develop methods which cover a broad range of pesticides. In this work, a qualitative multi-screening method for pesticides was developed by use of HPLC-ESI-Q-TOF. 110 pesticides were chosen for the creation of a personal compound database and library (PCDL). The MassHunter Qualitative Analysis software from Agilent Technologies was used to identify the analytes. The software parameter settings were optimised to produce a low number of false positive as well as false negative results. The method was validated for 78 selected pesticides. However, the validation criteria were not fulfilled for 45 analytes. Due to this result, investigations were started to elucidate reasons for the low detectability. It could be demonstrated that the three main causes of the signal suppression were the co-eluting matrix (matrix effect), the low sensitivity of the analyte in standard solution and the fragmentation of the analyte in the ion source (in-source collision-induced dissociation). In this paper different examples are discussed showing that the impact of these three causes is different for each analyte. For example, it is possible that an analyte with low signal intensity and an intense fragmentation in the ion source is detectable in a difficult matrix, whereas an analyte with a high sensitivity and a low fragmentation is not detectable in a simple matrix. Additionally, it could be shown that in-source fragments are a helpful tool for an unambiguous identification.
We introduce for the first time a paper-based analytical device (PAD) for the non-enzymatic detection of glucose by modifying a screen-printed carbon electrode with cobalt phthalocyanine, graphene ...and an ionic liquid (CoPc/G/IL/SPCE). The modifying composite was characterized by UV–visible spectroscopy, energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The disposable devices show excellent conductivity and fast electron transfer kinetics. The results demonstrated that the modified electrode on PADs had excellent electrocatalytic activity towards the oxidation of glucose with NaOH as supporting electrolyte (0.1M). The oxidation potential of glucose was negatively shifted to 0.64V vs. the screen-printed carbon pseudo-reference electrode. The paper-based sensor comprised a wide linear concentration range for glucose, from 0.01 to 1.3mM and 1.3–5.0mM for low and high concentration of glucose assay, respectively, with a detection limit of 0.67µM (S/N = 3). Additionally, the PADs were applied to quantify glucose in honey, white wine and human serum. The disposable, efficient, sensitive and low-cost non-enzymatic PAD has great potential for the development of point-of-care testing (POCT) devices that can be applied in healthcare monitoring.
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•Non-enzymatic glucose sensor on paper-based analytical devices for the first time.•Wide linear dynamic ranges (0.01–1.3mM and 1.3–5.0mM).•Successful determinations of glucose in food and blood samples.•Low detection limit of 0.67µM.
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