Evaluation of Turmeric Powder Adulterated with Metanil Yellow Using FT-Raman and FT-IR Spectroscopy

Recent advances in electrochemical detection of common azo dyes

PURPOSE

Food forensics is an emerging field and the initial part of this review showcases the toxic effects and the instrumental methods applied for the detection of the most commonly used azo dyes. Electrochemical detection has a lot of advantages and hence the significance of the most important techniques used in the electrochemical detection is discussed. The major part of this review highlights the surface modified electrodes, utilized for the detection of the most important azo dyes to achieve low detection limit (LOD).

METHODS

A thorough literature study was conducted using scopus, science direct and other scientific databases using specific keywords such as toxic azo dyes, electrochemical detection, modified electrodes, LOD etc. The recent references in this field have been included.

RESULTS

From the published literature, it is observed that with the growing interests in the field of electrochemical techniques, a lot of importance have been given in the area of modifying the working electrodes. The results unambiguously show that the modified electrodes outperform bare electrodes and offer a lower LOD value.

CONCLUSION

According to the literature reports it can be concluded that, compared to other detection methods, electrochemical techniques are much dependable and reproducible. The fabrication of the electrode material with the appropriate modifications is the main factor that influences the sensitivity. Electrochemical sensors can be designed to be more sensitive, more reliable, and less expensive. These sensors can be effectively used by toxicologists to detect trace amounts of harmful dyes in food samples.

Sequestration of an Azo Dye by a Potential Biosorbent: Characterization of Biosorbent, Adsorption Isotherm and Adsorption Kinetic Studies

This study explores the detailed characterization of a biosorbent (Hen Feather) and its efficient use in eradicating the azo dye Metanil Yellow (MY) from its aqueous solutions. Effects of a range of experimental parameters, including pH, initial dye concentration, biosorbent dosage and contact time on the adsorption, were studied. A detailed physical and chemical characterization of the biosorbent was made using SEM, XRD, XPS and FTIR. During the optimization of adsorption parameters, the highest dye uptake of almost 99% was recorded at pH 2, dye concentration 2 × 10-5 M, 0.05 g of biosorbent and a contact period of 75 min. Various adsorption isotherm models were studied to gather different adsorption and thermodynamic parameters. The linearity of the Langmuir, Freundlich and D-R adsorption isotherms indicate homogeneous, multilayer chemisorption with high adsorption affinity between the dye and biosorbent. Values of the changes in the Gibbs free energy (ΔG°) and the enthalpy (ΔH°) of the adsorption process have been calculated, these values indicate that it is a spontaneous and endothermic process. Kinetics of the adsorption were also measured, and it was established that the adsorption of MY over Hen Feather follows a pseudo-second-order kinetic model at temperatures 30, 40 and 50 °C. The findings of this investigation clearly indicate that the studied biosorbent exhibits a high affinity towards the dye (MY), and it can be effectively, economically and efficiently used to sequestrate and eradicate MY from its aqueous solutions.

Hybrid method for accurate starch estimation in adulterated turmeric using Vis-NIR spectroscopy

Turmeric is widely used as a health supplement and foodstuff in South East Asian countries because of its medicinal benefits. Like several other plants and peppers, turmeric is prone to exploitation because of its economic value, rising consumer need, and essential food element that adds colour and flavour. Due to this, quick and comprehensive testing processes are needed to detect adulterants in turmeric. In this study, pure turmeric powders were mixed with starch in proportions ranging from 0 to 50% with a 1% variation to obtain different combinations. Reflectance spectra of pure turmeric and starch mixed samples were recorded using a JASCO-V770 spectrometer from 400 to 2050 nm. The recorded spectra were pre-processed using a Multiplicative Scatter Correction (MSC) and Standard Normal Variate (SNV). The Savitzky-Golay (SG) filter was initially applied to these original (X), MSC, and SNV-corrected spectra. Secondly, the Extra Tree Regressor (ETR) feature selection method was employed to select the best features. Finally, principal component analysis (PCA) was used to reduce the dimension of the selected features. The stacked generalization method was applied to improve the performance of this work. Both regressors and classifier stacking techniques have been tested with different classification and regression methods. The K-Nearest Neighbours (KNN), Decision Tree (DT), and Random Forest (RF) models were used as base learners, and Logistic Regression (LRC) was used as a meta-model for classification and Linear Regression (LR) for regression analysis. The proposed method achieved the best regression performance with r2 of 0.999, Root Mean Square Error (RMSE) of 0.206, Ratio of Performance to Deviation (RPD) of 73.73, and Range Error Ratio (RER) of 480.58, whereas 100% F1 score and Matthew's Correlation Coefficient (MCC) classification performance.

Dye-Modified, Sonochemically Obtained Nano-SnS2 as an Efficient Photocatalyst for Metanil Yellow Removal

We investigate the possibility of modification of SnS2 powder through sonochemical synthesis with the addition of an organic ligand. For that purpose, two organic dyes are used, Phenol Red and Anthraquinone Violet. All obtained powders are characterized using XRD, SEM, EDX, FT-IR, and UV-Vis investigations. Synthesized samples showed composition and structural properties typical for sonochemically synthesized SnS2. However, investigation with the Tauc method revealed that SnS2 powder modified with Phenol Red exhibits a significant shift in value of optical bandgap to 2.56 eV, while unmodified SnS2 shows an optical bandgap value of 2.42 eV. The modification of SnS2 powder with Anthraquinone Violet was unsuccessful. The obtained nanopowders were utilized as photocatalysts in the process of Metanil Yellow degradation, revealing that SnS2 modified with Phenol Red shows about 23% better performance than the unmodified one. The mean sonochemical efficiency of the performed synthesis is also estimated as 9.35 µg/W.

Synthesis, Characterization, and Evaluation of a Novel Molecularly Imprinted Polymer (MIP) for Selective Quantification of Curcumin in Real Food Sample by UV-Vis Spectrophotometry

Curcumin is the main colorant of the curcuma longa plant, a food with many benefits for human health. This work aims to synthesize a novel molecularly imprinted polymer (MIP) for the selective detection of curcumin in real samples obtained from the local market of Peru. MIPs were synthesized via bulk polymerization using curcumin, acrylamide, ethylene glycol dimethacrylate, ABCV, and acetonitrile. FTIR spectra showed equal spectra for MIP and NIP. N2 physisorption analysis presented a higher value BET surface for the MIP (28.5 m2 g-1) compared to the NIP (18.5 m2 g-1). The adsorption capacity of the MIP was evaluated using UV-vis spectrophotometry in the band around 430 nm. The adsorption kinetics found were of pseudo-second-order and a Qe value of 16.2 mg g-1. Furthermore, the adsorption process resembles the Freundlich adsorption model with a heterogeneity factor of less than 1 (0.61) and Kf greater for MIP (1.97). The selectivity test indicated that MIP is more selective for curcumin (Q = 13.20 mg g-1) than against interferents (Q = 2.19 mg g-1). The specific selectivity factor (S) obtained for the interferents was greater than 1 which indicates a good selectivity. Finally, the application of MIP in real samples using UV-vis spectrophotometry yielded a recovery value greater than 70%.

Graphene Modification by Curcuminoids as an Effective Method to Improve the Dispersion and Stability of PVC/Graphene Nanocomposites

A large amount of graphene-related research is its use as a filler for polymer composites, including thin nanocomposite films. However, its use is limited by the need for large-scale methods to obtain high-quality filler, as well as its poor dispersion in the polymer matrix. This work presents polymer thin-film composites based on poly(vinyl chloride) (PVC) and graphene, whose surfaces were modified by curcuminoids. TGA, UV-vis, Raman spectroscopy, XPS, TEM, and SEM methods have confirmed the effectiveness of the graphene modification due to π-π interactions. The dispersion of graphene in the PVC solution was investigated by the turbidimetric method. SEM, AFM, and Raman spectroscopy methods evaluated the thin-film composite's structure. The research showed significant improvements in terms of graphene's dispersion (in solutions and PVC composites) following the application of curcuminoids. The best results were obtained for materials modified with compounds obtained from the extraction of the rhizome of Curcuma longa L. Modification of the graphene's surface with these compounds also increased the thermal and chemical stability of PVC/graphene nanocomposites.

Evening primrose oil attenuates oxidative stress, inflammation, fibrosis, apoptosis, and ultrastructural alterations induced by metanil yellow in the liver of rat: a histological, immunohistochemical, and biochemical study

The food color metanil yellow (Myl) is hazardous to several body systems. Evening primrose oil (EPO) was reported to have anti-inflammatory and anti-oxidant properties. The present work investigated the impact of Myl on the hepatic structure and function of rats and evaluated the protective effect of EPO. Forty adult male rats were divided into four groups: control, EPO (5 g/kg/day), Myl (200 mg/kg/day), and EPO- Myl group. Myl significantly increased liver enzymes, advanced glycation end products (AGE), oxidative stress parameters, pro-inflammatory cytokines, nuclear factor kappa B (NF-κB), and inducible nitric oxide synthase (iNOS). Blood vessels in the liver were dilated and congested, with cellular infiltration around them and associated with fibrosis. The hepatocytes were vacuolated and had dark nuclei. The immunohistochemical expression of iNOS, glial fibrillary acidic protein (GFAP), and Bax was significantly elevated. Ultrastructurally, the hepatocytes showed lipid droplets, irregular condensed nuclei with widened perinuclear space, dilated rER, mitochondria with destructed cristae, and multiple vacuoles. Dilated congested blood sinusoids and collagen fiber bundles were seen between hepatocytes. Interestingly, these alterations were less pronounced in rats co-administrated with EPO and Myl. In conclusion, EPO can protect liver against the toxic effects of Myl due to its anti-inflammatory and anti-oxidant activities.

Determination of metanil yellow dye in turmeric powder using a unique fluorescence Europium doped carbon dots

Turmeric, a spice known for its therapeutic benefits, is a major source of curcumin which is a polyphenol with anti-inflammatory properties. It aids in treating arthritis, anxiety, metabolic syndrome, liver disease, hyperlipidemia, and inflammatory diseases. In this study, a novel fluorescence probe was designed to detect the adulteration of curcumin by metanil yellow (a harmful artificial dye). The probe was synthesized from the carbonization and conversion of the Tannic acid-Eu³⁺ complex to bright fluorescence Eu-carbon dots in the presence of orthophosphoric acid. The size, morphological, and optical features of the formed Eu-carbon dots were characterized by UV, SEM, TEM, and FTIR techniques. Furthermore, the formed Eu-carbon dots possess unique fluorescence excitation and emission features at 307.5 nm and 340.6 nm, respectively. These fluorescence features can be successfully quenched upon the addition of metanil yellow dye. The value of quenching in the fluorescence intensity of the Eu-C-dots was directly proportional to the dye's concentration. The LOD value for the proposed method was 0.390 µg/mL with a linear range of 1.0-15.0 µg/mL. Furthermore, the methodology exhibited good recovery values for determining the studied dye without any interference from the presence of curcumin.

Therapeutic Effect of Curcumin on Metabolic Diseases: Evidence from Clinical Studies

Metabolic diseases have become a serious threat to human health worldwide. It is crucial to look for effective drugs from natural products to treat metabolic diseases. Curcumin, a natural polyphenolic compound, is mainly obtained from the rhizomes of the genus Curcuma. In recent years, clinical trials using curcumin for the treatment of metabolic diseases have been increasing. In this review, we provide a timely and comprehensive summary of the clinical progress of curcumin in the treatment of three metabolic diseases, namely type 2 diabetes mellitus (T2DM), obesity and non-alcoholic fatty liver disease (NAFLD). The therapeutic effects and underlying mechanisms of curcumin on these three diseases are presented categorically. Accumulating clinical evidence demonstrates that curcumin has good therapeutic potential and a low number of side effects for the three metabolic diseases. It can lower blood glucose and lipid levels, improve insulin resistance and reduce inflammation and oxidative stress. Overall, curcumin may be an effective drug for the treatment of T2DM, obesity and NAFLD. However, more high-quality clinical trials are still required in the future to verify its efficacy and determine its molecular mechanisms and targets.

Metanil Yellow dye adsorption using green and chemical mediated synthesized manganese ferrite: An insight into equilibrium, kinetics and thermodynamics

Green Manganese Ferrite (GMF) and Chemical mediated Manganese Ferrite (CMF) were designed and prepared via in situ co-precipitation method and their adsorption potential was compared using the model dye, Metanil Yellow (MY). Previously, an extract of aquatic macrophyte and metal chloride were employed for the development of ecofriendly GMF. Alternatively, CMF has been synthesized through chemical co-precipitation from metal chloride precursors. Several characterization methods, including PSA, BET, TGA, DSC, FTIR, SEM, VSM, EDX, and XRD, were analyzed to reveal the structural and functional properties of the as-synthesized GMF and CMF. Their MY adsorption performances were tested as the function of the operational conditions such as initial solution pH, temperature, nanocomposite dosage, and dye concentration in a batch mode of operation. The pseudo-second order MY adsorption process fits best in Langmuir model which yielded the maximal monolayer adsorption capacity (q_max) of 391.34 mg/g for GMF and 271.89 mg/g for CMF. This outperformance of GMF over CMF was observed due to the augmentation of specified surface functional moieties derived from the phyto-constituents of macrophages. Further, the thermodynamic studies confirmed the chemisorptive and exothermic nature of adsorption processes. Conclusively, with the ease of regeneration and reuse potential, GMF and CMF could be viable contenders for scale up and industrial applications.

Chemical Characterization for the Detection of Impurities in Tainted and Natural Curcuma longa from India Using LIBS Coupled with PCA

The present manuscript explores a spectroscopic technique to select turmeric powder, free from impurities, and has compounds of medicinal importance among the tainted and natural turmeric. Six Curcuma longa (turmeric powder) samples, named S1, S2, S3, S4, S5, and S6, were analyzed to discriminate between tainted and natural turmeric using the LIBS and multivariate technique. Other techniques such as UV–Vis, FTIR, and EDX are also used to ascertain the elements/compounds showing the medicinal properties of C. longa. Spectral lines of carbon, sodium, potassium, magnesium, calcium, iron, strontium, barium, and electronic bands of CN molecules were observed in the LIBS spectra of turmeric samples. Spectral signatures of toxic elements such as lead and chromium are also observed in the LIBS spectra of all samples except S6. Adulteration of metanil yellow, a toxic azo dye, is used to increase the appearance of curcumin when the actual curcumin content is low. The presence of spectral lines of lead and chromium in the LIBS spectra of S1 to S5 suggested that it may be adulterated with lead chromate which is used for coloring turmeric. Further, the presence of sulfur in EDX analysis of sample S5 indicates that it may also have been adulterated with metanil (C18H14N3NaO3S). The concentration of samples’ constituents was evaluated using CF-LIBS, and EDX was used to verify the results obtained by CF-LIBS. The principal component analysis applied to the LIBS data of the turmeric samples has been used for instant discrimination between the sample based on their constituents. We also analyzed antioxidant activity and total phenolic and flavonoid content of different turmeric samples and found a negative Pearson correlation with heavy metals. The presence of curcumin in turmeric is confirmed using LIBS and UV–Vis, which have medicinal properties.

A Comparative Study of Benchtop and Portable NIR and Raman Spectroscopic Methods for the Quantitative Determination of Curcuminoids in Turmeric Powder

Turmeric consumption is continually increasing worldwide. Curcuminoids are major active constituents in turmeric and are associated with numerous health benefits. A combination of spectroscopic methods and chemometrics shows the suitability of turmeric for food quality control due to advantages such as speed, versatility, portability, and no need for sample preparation. Five calibration models to quantify curcuminoids in turmeric were proposed using benchtop and portable devices. The most remarkable results showed that Raman and NIR calibration models present an excellent performance reporting RMSEP of 0.44% w/w and 0.41% w/w, respectively. In addition, the five proposed methods (FT-IR, Raman, and NIR) were compared in terms of precision and accuracy. The results showed that benchtop and portable methods were in good agreement and that there are no significant differences between them. This study aims to foster the use of portable devices for food quality control in situ by demonstrating their suitability for the purpose.

Rapid determination of metanil yellow in turmeric using a molecularly imprinted polymer dispersive solid-phase extraction and visible light spectrophotometry

The present study aimed to develop a sensitive and available method for determining metanil yellow (MY) as an adulterating agent in food samples. Solid-phase extraction was chosen for pre-concentrating metanil yellow prior to its determination using a validated UV-spectrophotometric method. The precipitation polymerization method was applied to synthesize a range of molecularly imprinted polymers (MIPs) for selective extraction of MY. Polymers were characterized by SEM and FTIR and investigated for MY extraction through batch rebinding experiments. The extraction process was optimized in the term of pH, time, capacity, and the desorbing solvent. Results of this study showed the critical role of template/functional monomer ratio in the preparation of the MIPs. The developed MIP solid-phase extraction/UV-spectrophotometric method was employed for determining MY in spiked samples and showed 88.10-92.76% recovery for turmeric samples containing 0.1-10 mg/kg MY. The developed method was shown selective for MY in the presence of another azo dye.

Advances in Fingerprint Analysis for Standardization and Quality Control of Herbal Medicines

Herbal drugs or herbal medicines (HMs) have a long-standing history as natural remedies for preventing and curing diseases. HMs have garnered greater interest during the past decades due to their broad, synergistic actions on the physiological systems and relatively lower incidence of adverse events, compared to synthetic drugs. However, assuring reproducible quality, efficacy, and safety from herbal drugs remains a challenging task. HMs typically consist of many constituents whose presence and quantity may vary among different sources of materials. Fingerprint analysis has emerged as a very useful technique to assess the quality of herbal drug materials and formulations for establishing standardized herbal products. Rather than using a single or two marker(s), fingerprinting techniques take great consideration of the complexity of herbal drugs by evaluating the whole chemical profile and extracting a common pattern to be set as a criterion for assessing the individual material or formulation. In this review, we described and assessed various fingerprinting techniques reported to date, which are applicable to the standardization and quality control of HMs. We also evaluated the application of multivariate data analysis or chemometrics in assisting the analysis of the complex datasets from the determination of HMs. To ensure that these methods yield reliable results, we reviewed the validation status of the methods and provided perspectives on those. Finally, we concluded by highlighting major accomplishments and presenting a gap analysis between the existing techniques and what is needed to continue moving forward.

Metabolomics-based profiling for quality assessment and revealing the impact of drying of Turmeric (Curcuma longa L.)

Turmeric, the rhizomes of Curcuma longa L., is one of the top selling spices, food preservatives, and food colorants. In addition, it exhibits health promoting benefits owing to its unique phytochemical composition. Nevertheless, it is commonly subjected to heat drying, hence, the dried powder is the most used form and can easily be adulterated with allied species. Therefore, our research aimed to profile the phytochemical composition and investigate the impact of drying of turmeric. Extraction and fractionation followed by LC- and GC–MS analysis resulted in the identification of a total of 161 metabolites belonged to various phytochemical classes. Moreover, multivariate data analysis identified curcuminoids, terpecurcumins, and organic acids as potential markers for drying. Based on the applied analytical techniques in combination with chemometrics, these investigations have succeeded to provide good coverage of the metabolome of turmeric in both fresh and dried forms.

Simple One-step Solid-state Synthesis of Highly Crystalline N Doped Carbon Dots As Selective Turn Off-sensor for Picric Acid and Metanil Yellow

A simple one-step solid-state pyrolysis method has been employed to synthesize highly crystalline nitrogen-doped carbon dots using adipic acid and urea as carbon and nitrogen sources. The prepared carbon dots displayed UV emission ( λ_ex = 290 nm and λ_em = 370 nm) and blue fluorescence emission ( λ_ex = 360 nm and λ_em = 420 nm). These crystalline nitrogen-doped carbon dots exhibited a quantum yield of 6% with tryptophan as standard at 370 nm emission and 14% with quine sulfate as standard at 420 nm emission. The synthesized carbon dots were spherical, having a mean particle diameter of 2.56 ± 0.57 nm. The prepared carbon dots have large functional groups on their surface, which renders excellent water solubility to them. Carbon dots was used as selective and sensitive turn off sensor for detection of picric acid Metanil yellow with the linear response for picric acid ranging from 2 μM to 22 μM and 2-45 μM with a detection limit of 0.06 μM and 0.45 μM and for Metanil yellow ranging from 1 μM to 30 μM with a detection limit of 0.32 μM. The mechanism for detecting metanil yellow is proposed to be the inner filter effect. At the same time, it is both the inner filter effect and FRET for picric acid. The actual sample application of carbon dots as a nanosensor was tested to detect metanil yellow as an adulterant in turmeric powder.

Agricultural Potentials of Molecular Spectroscopy and Advances for Food Authentication: An Overview

Meat, fish, coffee, tea, mushroom, and spices are foods that have been acknowledged for their nutritional benefits but are also reportedly targets of fraud and tampering due to their economic value. Conventional methods often take precedence for monitoring these foods, but rapid advanced instruments employing molecular spectroscopic techniques are gradually claiming dominance due to their numerous advantages such as low cost, little to no sample preparation, and, above all, their ability to fingerprint and detect a deviation from quality. This review aims to provide a detailed overview of common molecular spectroscopic techniques and their use for agricultural and food quality management. Using multiple databases including ScienceDirect, Scopus, Web of Science, and Google Scholar, 171 research publications including research articles, review papers, and book chapters were thoroughly reviewed and discussed to highlight new trends, accomplishments, challenges, and benefits of using molecular spectroscopic methods for studying food matrices. It was observed that Near infrared spectroscopy (NIRS), Infrared spectroscopy (IR), Hyperspectral imaging (his), and Nuclear magnetic resonance spectroscopy (NMR) stand out in particular for the identification of geographical origin, compositional analysis, authentication, and the detection of adulteration of meat, fish, coffee, tea, mushroom, and spices; however, the potential of UV/Vis, 1H-NMR, and Raman spectroscopy (RS) for similar purposes is not negligible. The methods rely heavily on preprocessing and chemometric methods, but their reliance on conventional reference data which can sometimes be unreliable, for quantitative analysis, is perhaps one of their dominant challenges. Nonetheless, the emergence of handheld versions of these techniques is an area that is continuously being explored for digitalized remote analysis.

Non-Invasive Methods for Predicting the Quality of Processed Horticultural Food Products, with Emphasis on Dried Powders, Juices and Oils: A Review

This review covers recent developments in the field of non-invasive techniques for the quality assessment of processed horticultural products over the past decade. The concept of quality and various quality characteristics related to evaluating processed horticultural products are detailed. A brief overview of non-invasive methods, including spectroscopic techniques, nuclear magnetic resonance, and hyperspectral imaging techniques, is presented. This review highlights their application to predict quality attributes of different processed horticultural products (e.g., powders, juices, and oils). A concise summary of their potential commercial application for quality assessment, control, and monitoring of processed agricultural products is provided. Finally, we discuss their limitations and highlight other emerging non-invasive techniques applicable for monitoring and evaluating the quality attributes of processed horticultural products. Our findings suggest that infrared spectroscopy (both near and mid) has been the preferred choice for the non-invasive assessment of processed horticultural products, such as juices, oils, and powders, and can be adapted for on-line quality control. Raman spectroscopy has shown potential in the analysis of powdered products. However, imaging techniques, such as hyperspectral imaging and X-ray computed tomography, require improvement on data acquisition, processing times, and reduction in the cost and size of the devices so that they can be adopted for on-line measurements at processing facilities. Overall, this review suggests that non-invasive techniques have the potential for industrial application and can be used for quality assessment.

Metanil yellow promotes oxidative stress, astrogliosis, and apoptosis in the cerebellar cortex of adult male rat with possible protective effect of scutellarin: A histological and immunohistochemical study

Metanil yellow is a food dye that has harmful impacts on different body systems. Scutellarin has antioxidant, antiapoptotic, and anti-inflammatory activities. The aim of the current research was to study the effect of chronic administration of metanil yellow on the cerebellar cortex of rats and to evaluate the protective effect of scutellarin. Forty adult male rats were allocated into four groups: group I acted as control, group II was administrated scutellarin (100 mg/kg/day), group III was administrated metanil yellow (200 mg/kg/day), and group IV was administrated scutellarin and metanil yellow as in group II and group III. The agents were administered via oral gavage for 8 weeks. Metanil yellow induced a significant rise in the malondialdehyde coupled with a significant reduction in the superoxide dismutase and glutathione peroxidase. The Purkinje cells were irregular and shrunken with condensed nuclei. A significant elevation in glial fibrillary acidic protein (GFAP) and cleaved caspase-3 as well as a significant reduction of synaptophysin expression were revealed in comparison with the control group. Interestingly, few changes were noticed in rats given metanil yellow concomitant with scutellarin. In conclusion, scutellarin could protect against metanil yellow-induced alterations in the cerebellar cortex by reducing oxidative stress and minimizing gliosis.

Highly Selective and Sensitive Benzimidazole Based Bifunctional Sensor for Targeting Inedible Azo Dyes in Red Chilli, Red Food Color, Turmeric Powder, and Cu(Ii) in Coconut Water

In this study, a simple Benzimidazole based bifunctional chemosensor 4-(2-(3,4-dimethoxyphenyl)-1H-benzo[d]imidazol-6-yl) benzene-1,2-diamine, L was synthesized and characterized. The sensor proved to be selective and sensitive towards detecting banned azo dyes Sudan Dye I, II, and Metanil Yellow via fluorescence turn-off response. The proposed mechanism of fluorescence quenching was the inner filter effect. LODs for Sudan I, II, and Metanil Yellow were found to be 0.009 µM, 0.012 µM, and 0.0073 µM, respectively. The developed chemosensor also showed a colorimetric response towards Cu (II) ions via an apparent color change from yellow to pink. LOD for Cu (II) ions was found to be 1.2 µM. The synthesized benzimidazole based bifunctional chemosensor was adequately tested to determine Sudan I in Red chili powder and red Food color samples, Metanil yellow in turmeric powder, and Cu(II) packaged coconut water.

Determination of Curcuminoids in Turmeric Dietary Supplements by HPLC-DAD: Multi-laboratory Study Through the NIH-ODS/NIST Quality Assurance Program

Background

Turmeric is a medicinal herb containing curcuminoids, used as quality markers in dietary supplements. In 2016, an AOAC First Action Official Method^SM was adopted for quantitation of curcuminoids and requires multi-laboratory reproducibility data for Final Action status.

Objective

To collect reproducibility data for the quantitation of curcuminoids in dietary supplements through the National Institutes of Health Office of Dietary Supplements/National Institute of Standards and Technology Quality Assurance Program (QAP).

Method

Laboratories that participated in the QAP by following the Official Methods of Analysis^SM Method 2016.16, submitted data for ten turmeric products. The data were analyzed for mean, repeatability, and reproducibility standard deviations, repeatability, and reproducibility.

Results

The initial data collection resulted in insufficient replicates (five) for each test sample to determine reproducibility, therefore laboratories were provided additional materials resulting in an incremental data approach. For homogenous products, reproducibility for curcumin ranged from 3.4 to 10.3%, bisdemethoxycurcumin with reproducibility ranging from 6.4 to 14.8%, and demethoxycurcumin ranging from 5.6 to 9.9%. The method was unsuitable for the quantitation of curcuminoids in complex smoothie products, products containing microbeads, or tinctures based on interlaboratory variances. Recommendations were provided for future multi-laboratory studies performed through QAPs and incremental approaches.

Conclusions

Method 2016.16 is suitable for the quantitation of curcuminoids and should be adopted for Final Action status for single and multi-ingredient dietary supplements containing dried roots, dried powders/extracts in bulk material, capsules, and softgels.

Highlights

Reproducibility for Method 2016.16 was collected through a non-traditional incremental data multi-laboratory study. The method is suitable for quantitation of curcuminoids in most common dietary supplements.

An evaluation of IR spectroscopy for authentication of adulterated turmeric powder using pattern recognition

Turmeric powder is a widely consumed spice, making it an attractive target for adulteration, which is not easily detected. The study examined the simultaneous use of IR spectroscopy in combination with controlled (PCA) and uncontrolled (PLS-DA and CMCA) pattern recognition techniques to detect and classify Sudan Red, starch and metanil yellow fraud in turmeric powder nondestructively. The results showed that the two major peaks in turmeric powder at 1625 cm^-1 and 1600 cm^-1 are not present in Sudan Red, starch and metanil yellow because these materials lack this functional group. Data distribution at the two PC locations showed clearly scattered clusters according to the four mixing studied models (turmeric powder, turmeric powder-Sudan Red mixture, turmeric powder-starch mixture and turmeric powder-metanil yellow mixture), but there was a clear overlap between turmeric powder and turmeric powder - Sudan red mixture. Both PLS-DA and SIMCA supervised methods showed satisfactory discrimination. The results also showed that in all the sample groups, when the samples were classified by PLS-DA, the values were higher compared to the SIMCA model. The overall precision of the SIMCA and PLS-DA classifier were 82% and 92%, respectively. However, when considering only two main categories adulterated (the samples at the groups 2, 3 and 4) and pure (the samples at the group 1), an acceptable degree of separation between the resulting classes was obtained. Consequently, IR spectroscopy with pattern recognition methods was found to be a promising tool for nondestructive grouping of turmeric powder samples with different types of adulteration in turmeric powder.

Fraud Detection of Herbal Medicines Based on Modern Analytical Technologies Combine with Chemometrics Approach: A Review

Fraud in herbal medicines (HMs), commonplace throughout human history, is significantly related to medicinal effects with sometimes lethal consequences. Major HMs fraud events seem to occur with a certain regularity, such as substitution by counterfeits, adulteration by addition of inferior production-own materials, adulteration by chemical compounds, and adulteration by addition of foreign matter. The assessment of HMs fraud is in urgent demand to guarantee consumer protection against the four fraudulent activities. In this review, three analysis platforms (targeted, non-targeted, and the combination of non-targeted and targeted analysis) were introduced and summarized. Furthermore, the integration of analysis technology and chemometrics method (e.g., class-modeling, discrimination, and regression method) have also been discussed. Each integration shows different applicability depending on their advantages, drawbacks, and some factors, such as the explicit objective analysis or the nature of four types of HMs fraud. In an attempt to better solve four typical HMs fraud, appropriate analytical strategies are advised and illustrated with several typical studies. The article provides a general workflow of analysis methods that have been used for detection of HMs fraud. All analysis technologies and chemometrics methods applied can conduce to excellent reference value for further exploration of analysis methods in HMs fraud.

A review on the application of spectroscopy to the condiments detection: from safety to authenticity

Condiments are the magical ingredients that make the food present a richer taste. In recent years, due to the increasing consciousness of food safety and human health, much progress has been made in developing rapid and nondestructive techniques for the evaluation of food condiments safety, authentication, and traceability. The potential of spectroscopy techniques, such as near-infrared (NIR), mid-infrared (MIR), Raman, fluorescence, inductively coupled plasma (ICP), and hyperspectral imaging techniques, has been widely enhanced by numerous applications in this field because of their advantages over other analytical techniques. Following a brief introduction of condiment and safety basics, this review mainly focuses on recent vibrational and atomic spectral applications for condiment nondestructive analysis and evaluation, including (1) chemical hazards detection; (2) microbiological hazards detection; and (3) authenticity concerns. The review shows current spectroscopies to be effective tools that will play indispensable roles for food condiment evaluation. In addition, online/real-time applications of these techniques promise to be a huge growth field in the near future.

Carbon-based Nanomaterials and Curcumin: A Review of Biosensing Applications

Curcumin, the main active constituent of turmeric (Curcuma longa L.), is a naturally occurring phenolic compound with a wide variety of pharmacological activities. Although it has multiple pharmaceutical properties, its bioavailability and industrial usage are hindered due to rapid hydrolysis and low water solubility. Due to the growing market of curcumin, exact determination of curcumin in trade and human biological samples is important for monitoring therapeutic actions. Different nanomaterials have been suggested for sensing curcumin; and in this case, carbon-based nanomaterials (CNMs) are one of the most outstanding developments in nanomedicine, biosensing, and regenerative medicine. There are a considerable number of reports which have shown interesting potential of CNMs-based biosensors in the sensitive and selective detection of curcumin. Therefore, this review aims to increase understanding the interaction of curcumin with CNMs in the context of biosensing.

Fabrication of Bacterial Cellulose-Curcumin Nanocomposite as a Novel Dressing for Partial Thickness Skin Burn

The current study aimed to fabricate curcumin-loaded bacterial cellulose (BC-Cur) nanocomposite as a potential wound dressing for partial thickness burns by utilizing the therapeutic features of curcumin and unique structural, physico-chemical, and biological features of bacterial cellulose (BC). Characterization analyses confirmed the successful impregnation of curcumin into the BC matrix. Biocompatibility studies showed the better attachment and proliferation of fibroblast cells on the BC-Cur nanocomposite. The antibacterial potential of curcumin was tested against Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Salmonella typhimurium (S. typhimurium), and Staphylococcus aureus (S. aureus). Wound healing analysis of partial-thickness burns in Balb^c mice showed an accelerated wound closure up to 64.25% after 15 days in the BC-Cur nanocomposite treated group. Histological studies showed healthy granulation tissues, fine re-epithelialization, vascularization, and resurfacing of wound bed in the BC-Cur nanocomposite group. These results indicate that combining BC with curcumin significantly improved the healing pattern. Thus, it can be concluded that the fabricated biomaterial could provide a base for the development of promising alternatives for the conventional dressing system in treating burns.

Safety issues and harmful pharmacological interactions of nutritional supplements in Duchenne muscular dystrophy: considerations for Standard of Care and emerging virus outbreaks

At the moment, little treatment options are available for Duchenne muscular dystrophy (DMD). The absence of the dystrophin protein leads to a complex cascade of pathogenic events in myofibres, including chronic inflammation and oxidative stress as well as altered metabolism. The attention towards dietary supplements in DMD is rapidly increasing, with the aim to counteract pathology-related alteration in nutrient intake, the consequences of catabolic distress or to enhance the immunological response of patients as nowadays for the COVID-19 pandemic emergency. By definition, supplements do not exert therapeutic actions, although a great confusion may arise in daily life by the improper distinction between supplements and therapeutic compounds. For most supplements, little research has been done and little evidence is available concerning their effects in DMD as well as their preventing actions against infections. Often these are not prescribed by clinicians and patients/caregivers do not discuss the use with their clinical team. Then, little is known about the real extent of supplement use in DMD patients. It is mistakenly assumed that, since compounds are of natural origin, if a supplement is not effective, it will also do no harm. However, supplements can have serious side effects and also have harmful interactions, in terms of reducing efficacy or leading to toxicity, with other therapies. It is therefore pivotal to shed light on this unclear scenario for the sake of patients. This review discusses the supplements mostly used by DMD patients, focusing on their potential toxicity, due to a variety of mechanisms including pharmacodynamic or pharmacokinetic interactions and contaminations, as well as on reports of adverse events. This overview underlines the need for caution in uncontrolled use of dietary supplements in fragile populations such as DMD patients. A culture of appropriate use has to be implemented between clinicians and patients' groups.

Paper swab based SERS detection of non-permitted colourants from dals and vegetables using a portable spectrometer

Rising concern about the use of non-permitted colourants, in common food items such as dals and green vegetables sold in Indian markets, have led to a demand for low-cost point-of-use chemical analysis tools. Conventional food-analysis techniques involving tedious sample preparation protocols are not suited for in-field applications. Surface Enhanced Raman Spectroscopy (SERS) is an analytical technique that is well-suited for point-of-use chemical analysis with molecular level detection capability, which can also serve as a quality assurance tool for businesses. Effective and rapid signal collection from a large-area sample within a field-setting using disposable, low-cost SERS substrates is a key challenge in implementing such a solution. Herein, we demonstrate the use of inkjet-printed thin films comprising of robust nanostructured-silver as flexible, paper-based SERS (P-SERS) swabs for the direct detection of Metanil Yellow (MY) from toor dal (yellow split pigeon peas) samples and Malachite Green (MG) from green peas and green chillies. The macroscopic uniformity of these thin-films in combination with a portable Raman spectrometer equipped with orbital raster scanning (ORS™) technology for signal collection results in an unprecedented precision (RSD ∼ 1.6%) upon characterizing samples saturated with Rhodamine-6G (R6G), a standard Raman probe. As several food-cleansing products have appeared in the marketplace, the adulterant removal efficacy of some commercially available 'washes' as well as products such as 'ozoniser', which was determined by SERS characterization of swabs before and after use, is also reported.

Curcumin: Biological, Pharmaceutical, Nutraceutical, and Analytical Aspects

Turmeric is a curry spice that originated from India, which has attracted great interest in recent decades because it contains bioactive curcuminoids (curcumin, demethoxycurcumin, and bisdemethoxycurcumin). Curcumin (1,7-bis-(4-hydroxy-3-methoxyphenyl)-hepta-1,6-diene-3,5-dione), a lipophilic polyphenol may work as an anticancer, antibiotic, anti-inflammatory, and anti-aging agent as suggested by several in vitro, in vivo studies and clinical trials. However, poor aqueous solubility, bioavailability, and pharmacokinetic profiles limit curcumin’s therapeutic usage. To address these issues, several curcumin formulations have been developed. However, suboptimal sample preparation and analysis methodologies often hamper the accurate evaluation of bioactivities and their clinical efficacy. This review summarizes recent research on biological, pharmaceutical, and analytical aspects of the curcumin. Various formulation techniques and corresponding clinical trials and in vivo outcomes are discussed. A detailed comparison of different sample preparation (ultrasonic, pressurized liquid extraction, microwave, reflux) and analytical (FT-IR, FT-NIR, FT-Raman, UV, NMR, HPTLC, HPLC, and LC-MS/MS) methodologies used for the extraction and quantification of curcuminoids in different matrices, is presented. Application of optimal sample preparation, chromatographic separation, and detection methodologies will significantly improve the assessment of different formulations and biological activities of curcuminoids.

Detection of Additives and Chemical Contaminants in Turmeric Powder Using FT-IR Spectroscopy

Yellow turmeric (Curcuma longa) is widely used for culinary and medicinal purposes, and as a dietary supplement. Due to the commercial popularity of C. longa, economic adulteration and contamination with botanical additives and chemical substances has increased. This study used FT-IR spectroscopy for identifying and estimating white turmeric (Curcuma zedoaria), and Sudan Red G dye mixed with yellow turmeric powder. Fifty replicates of yellow turmeric-Sudan Red mixed samples (1%, 5%, 10%, 15%, 20%, 25% Sudan Red, w/w) and fifty replicates of yellow turmeric-white turmeric mixed samples (10%, 20%, 30%, 40%, 50% white turmeric, w/w) were prepared. The IR spectra of the pure compounds and mixtures were analyzed. The 748 cm^-1 Sudan Red peak and the 1078 cm^-1 white turmeric peak were used as spectral fingerprints. A partial least square regression (PLSR) model was developed for each mixture type to estimate adulteration concentrations. The coefficient of determination (R²_v) for the Sudan Red mixture model was 0.97 with a root mean square error of prediction (RMSEP) equal to 1.3%. R²_v and RMSEP for the white turmeric model were 0.95 and 3.0%, respectively. Our results indicate that the method developed in this study can be used to identify and quantify yellow turmeric powder adulteration.

Determination of curcuminoid content in turmeric using fluorescence spectroscopy

The potential of fluorescence spectroscopy is exploited for the characterization and comparison of different turmeric varieties based on curcuminoids content in turmeric powders. Fluorescence spectra from turmeric powders has been acquired by using excitation wavelengths from 300 to 470 nm with step of 10 nm to investigate the effect of excitation wavelengths on the emission of valuable ingredients for their characterization. Emission spectra revealed that fresh wet turmeric rhizomes show emission bands at 571 nm which is due to curcumin. It is found that main ingredient of turmeric powder is curcumin and best excitation wavelength is 467 nm for its maximum emission intensity. High Pressure Liquid Chromatography (HPLC) was used as alternate standard technique for determination of curcuminoid content in the reference samples. The curcumin content in the commercially available local turmeric brands were also evaluated, one brand showed significant covariance from standard fluorescent spectra of turmeric meaning this particular brand contained minimum curcumin content or have been severely adultered. In the next step the powders were heated at different temperatures from 60 °C to 150 °C (Normal cooking & frying temperatures) to observe the difference in emission spectra particularly keeping in view the molecular composition and curcuminoid content in turmeric. The results indicate that curcumin content gradually decreases above 90 °C. Principal component analysis (PCA) has been employed on all the data to statistically differentiate small molecular changes and adulteration by covariance calculations.