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Presence of Sudan I in food stuff can be problematic and need to be checked in order to protect our health from possible carcinogen. Therefore, it is essential to detect Sudan I by efficient, rapid and reliable method. In this work, we have designed a Ru(II) polypyridyl complex, [Ru(bpy)2(CIP)]2+ probe for the selective and sensitive detection of Sudan I. Upon addition of Sudan I to the solution of [Ru(bpy)2(CIP)]2+ in ethanol, the luminescence quenched rapidly, and linear concentration range with analyte has been obtained from 0.8 to 100 μM with the limit of detection as low as 0.26 μM (S/N = 3). The effective luminescence quenching was resulted due to the inner filter effect (IFE) between luminophore, [Ru(bpy)2(CIP)]2+ and quencher, Sudan I. Our spectroscopic study was essentially provided sufficient analytical evidences in order to prove occurrence of IFE mechanism. As there were no interferences observed in luminescence measurement from the other substances the present probe has been successfully applied for the detection of Sudan I in commercial chili powder sample, making the probe suitable for practical usage.

Recently, the determination of phenolic compounds in edible oils has aroused wide attention because of its beneficial effects on human health. The objective of this study was to determine the phenolic compounds in gurum seed oil obtained by different methods viz. screw press, supercritical CO2, and solvent extraction using HPLC. Results showed that the HPLC characterization of oil obtained by screw press revealed that kaempferol, quercetin, syringic acid, caffeic acid, and rutin were the main phenolic compounds accounting for 60.28 μg/g, 31.78 μg/g, 1.19 μg/g, 1.18 μg/g, and 0.83 μg/g, respectively. The HPLC characterization of oil obtained by supercritical CO2 extraction (SFE) revealed that kaempferol, rutin, epigallocatechin, and syringic acid were the main phenolic compounds accounting for 55.26 μg/g, 18.19 μg/g, 1.75 μg/g, and 1.36 μg/g, respectively. Caffeic acid and ferulic acid were predominant phenolic compounds accounting for 3.21 μg/g and 2.86 μg/g, respectively, in oil obtained by solvent extraction. Results showed that the gurum seed oil appears to be a novel promising source of biologically active constituents and may be incorporated as a functional ingredient in foods. Additionally, gurum seed oil as a rich source of natural antioxidants may play a vital role in decreasing the hazard of chronic infirmities. Thus, the examined gurum seed oil can be used in varied food preparations to supply nutritive and health benefits.

Sorghum sourdough made with lactic acid bacteria (LAB) and fruit products are of interest in the preparation of a variety of fermented baked products. In this study, different levels (10, 20, and 30%) of sorghum sourdough were fermented by a blend of L. plantarum and L. brevis and various levels of dry nabag pulp powder (1, 3, 5, and 7%). Physicochemical properties of dough and bread as well as the sensory evaluation were determined. Sorghum sourdough' pH decreased from 6.30 to 3.54, total titratable acidity (TTA) increased from 2.8 to 15 mL and bacteria count increased from 6.00E + 08 to 1.14E + 09, CFU/mL after 24 h of fermentation. The addition of sorghum sourdough and nabag powder progressively decreased pH and increased TTA values of bread and dough compared to the controls. Nabag powder significantly (p < 0.05) increased maximum dough fermentation height (Hm), compared to the control, however the other samples were lower (p < 0.05). The maximum gas fermentation height (H’m) and gas properties increased (p < 0.05) for all samples with different addition levels. Crust and crumb color were not affected by sorghum sourdough and nabag pulp powder except for 30% sorghum sourdough and 7% nabag pulp powder. These results showed sorghum sourdough and nabag pulp powder can be used in the bread formulations.

Gurum (Citrullus lanatus var. Colocynthoide) seed was evaluated for lipid, amino acid, mineral, proximate, sugar, vitamin composition, volatile compound and functional characteristics in seeking to identify nutritious plant containing a higher amount of nutrients that can be employed in food related industries. The gurum seed was found to be rich in fat (33.05%), crude fiber (26.42%), protein (18.55%), carbohydrates (14.41%), and ash (3.40%) and it has sufficient amino acids content. The gurum seed was found to have a higher content of minerals with potassium 2116.83 mg/100 g among highest followed by sodium 461.23 mg/100 g and magnesium 405.63 mg/100 g. Calcium, zinc, iron, copper and manganese are also present in a significant amount. Gurum seeds could be used as an affluent source of vitamins, mainly B6 and B9 with the amounts of 11.37 and 9.24 mg/100 g respectively, while sucrose constituted 41.5% of the all sugars. Oil of gurum seed has an altitude amount of unsaturated fatty acids, with C18:2 and C18:1 as the major acids, whereas, triglycerides as a major component of lipid classes. The gurum seed showed water absorption 3.46 mL /g and oil absorption 2.39 mL/g. The foaming capacity, stability of foam and emulsifying capacity were 18.5%, 16.55%, and 44.2%, respectively. 49 volatile compounds from the extract of gurum seeds were identified; with organic acids as a prime component. This study has shown the potentials of gurum seed, a by-product with a high nutritional value to provide sufficient economic resourceful raw material alternative to food industrial firms.

Due to clinical importance, detection of dopamine by using easy and rapid method is still ongoing challenge. Here we present a simple and quite efficient method for dopamine (DA) detection in alkalescent medium using in situ prepared Ru(II) complex and sodium dodecyl benzyl sulfonate (SDBS) as highly luminescent luminophore. The luminescence enhancement in the Ru(II) complex (Ru-CIP) has been observed in the miceller medium formed by SDBS. The capability to successively quench the luminescence intensity has been tested for variety of molecules and only dopamine as analyte found to be able to quench luminescence effectively. Hence selective quenching of luminescence by dopamine was used as a tool to detect dopamine and two linear concentration ranges has been established from 0.1 μM to 1μM and from 2 μM to 10 μM with limit of detection (LOD) is 6.6 nM (S/N = 3). Spectral evidence showed that luminescence quenching mechanism arose via Forster resonance energy transfer (FRET) among oxidized DA (i.e. DA quinone) and in situ generated Ru-CIP and SDBS assembly. Due to ultra sensitivity and high selectivity of the prescribed (Ru-CIP-SDBS) luminescent probe has a strong potential for practical analytical application in clinical diagnosis.

A novel phosphorescent, water-soluble cyclometallated iridium complex [(fppy)2Ir(BQCOOH)] (fppy = 4-(2-pyridyl) benzaldehyde, BQCOOH = 2,2′-biquinoline-4,4-dicarboxylic acid) (Ir-C) was synthesized and characterized. Analysis found that Ir-C exhibited strong orange-red phosphorescence, which peaked at 630 nm under alkaline conditions and remained stable (pH > 7.0). Its response signal decreased with the increasing acidity of the aqueous system. Ir-C worked as a quencher of the luminescence of nitrogen-doped carbon quantum dots (N-CQDs) with an electron transfer mechanism, and the prepared N-CQDs were introduced into the aqueous system of Ir-C to prepare a visual ratiometric pH probe. Due to the error of single emission probes in different environments, a visual ratiometric probe is more advantageous for accurate and simple detection of the acidity of water. At pH 2.5, the quenched luminescence signal can be restored with subsequent addition of bovine serum albumin (BSA) due to the several interactions between Ir-C and BSA, mainly electrostatic interactions, hydrophobic interactions, and deprotonation and protonation of the ligand. Based on this observed phenomenon, a “turn on” kind of luminescent sensor was constructed for quantification of BSA. Under optimal conditions, a wide linear detection range of 20–140 nM was obtained with a limit of detection (LOD) of 7 nM.

Electrochemical determination of phosphate in aqueous solutions attracts considerable interests in both biological and environmental fields. Because of the electrochemically inactive nature of phosphate, direct electrochemical detection of phosphate is still a highly challenging task. Herein, we reported a direct electrochemical approach for the determination of phosphate based on the oxidation of coordinated OH during the phase transition of calcium phosphates (CaPs). The mixture of amorphous CaPs and octacalcium phosphate (Ca

A novel ruthenium(II) polypyridine complex with an imidazole group linked with a conjugated structure has been synthesized and functioned as a novel luminescent probe for the quick and accurate detection of Cu2+. The coordination with Cu2+ resulted into the formation of stable cyclic structure which leads to luminescence quenching of RuL at the 621 nm. Under the optimal conditions, the linear concentration range was obtained from 0.25–12.0 μM and the corresponding detection limits were calculated to be 83.3 nM (S/N = 3) which is far lower than prescribed permissible limit by World Health Organization. The developed RuL luminescent probe has been applied for the detection of Cu2+ in environmental water sample successfully. Furthermore, the RuL probe applied in the cell imaging for detection of Cu2+, indicating its suitability for application in vivo. Thus, a simple and quick method has been established with high sensitivity and specificity for the detection of Cu2+.

The nanostructures and phase transformations of calcium phosphates (CaPs) on the solid-water interface have attracted a great deal of recent interests in wide research fields. The structural water molecules or the coordinated hydroxyl (OH) are crucial points of consideration for the phase transformation and the production of redox active intermediates with electrochemically stable species. In this work, nanostructured brushite (DCPD, CaHPO4•2H2O) was assembled in situ on Nafion modified glassy carbon electrode (GCE) in Ca(NO3)2 and NaH2PO4 solution. Upon application of cyclic voltammetric (CV) scan, a strong electrogenerated chemiluminescence (ECL) was observed at 1.0 V vs Ag/AgCl in pH 7.4 phosphate buffer solution. Characteristic emission signals at 634 nm and 1268 nm manifested the generation of singlet oxygen. Raman spectroscopy and X-ray diffraction (XRD) spectrum evidenced phase transformation during CV scans, and entailed CV peaks showed the transformative immediate species were attributed to the ECL. This finding provides one insight into the intermediate species during the CaPs phase transformation. Furthermore, the method presented in this work also supplied a new route for singlet oxygen generation from earth abundant materials.

First time the luminescent switch-on probe using novel water-soluble cyclometallated iridium complex (Ir-dc) has been developed for sensitive and selective detection of gluten in the presence of several interfering elements. Linear concentration range of gluten is obtained from 5 to 200 µg/mL with a limit of detection 2.6 µg/mL. The Ir-dc complex responded to the broad pH range which is advantageous for the detection of gluten in various food samples. Additionally, It has been successfully employed for the detection of gluten in commercial food samples of wheat flour and oats with highest recovery values, indicating applicability of Ir-dc for practical usage.

International audience; Click chemistry was used as an efficient method to covalently attach a chromophore to an amino acid. Such easily prepared model systems allow for time-resolved studies of one-electron oxidation reactions by the excitation of the chromophore by a laser flash. The model complex ruthenium-tryptophan (Ru-Trp) has been synthesised and studied for its photophysical and electrochemical properties. Despite a small driving force of less than 100 meV, excitation with a laser flash results in fast internal electron transfer leading to the formation of the protonated radical (Trp˙H(+)). At neutral pH electron transfer is followed by deprotonation to form the neutral Trp˙ radical with the rate depending on the concentration of water acting as the proton acceptor. The formation of the tryptophan radical was confirmed by EPR.

Click chemistry was used to assemble a trimetallic RuII–NiII–RuII complex made up of two tris(bipyridyl)ruthenium(II)-based photosensitisers and a nickel(II)–salen complex. The electrochemical and photophysical properties of the resulting photosensitiser–metal complex are discussed. Photoinduced activation triggered by visible light absorption induces a fast intramolecular charge shift from one of the chromophores to the salen cavity to generate a nickel(III)–salen species.