An investigation of radiolytic damage to biomolecules in foodstuffs

The development of an effective test system for detecting the irradiation status of foodstuffs is essential for the establishment of legislative control and consumer choice. For foodstuffs consisting mainly of water, treatment with ionising radiation initially generates highly reactive free radical species (hydroxyl radical (‘OH), hydrated electrons (e-aq) or hydrogen atoms (H)). These react extremely rapidly with a wide variety of “target" molecules in foodstuffs resulting in small but detectable chemical changes. Hence, assays for the assessment of ‘OH radical activity involve the identification and/or quantification of chemical species produced by the attack of ‘OH radical on a range of biomolecules occurring in foodstuffs. This study Involves an investigation of radiolytically-induced chemical modifications arising from the Interaction of ‘OH radical with naturally occurring aromatic compounds in fruits and vegetables. High performance liquid chromatography coupled with electrochemical detection has been applied to the analysis. In addition, the chemical nature of intermediates in, and end-products arising from the interaction of ‘0H radical with polyunsaturated fatty acids and carbohydrates Is reviewed by application of second-derivative (2D) electronic absorption spectrophotometry. The 2D spectrophotometric technique has not been previously applied to food studies and may serve as a potential “probe” for the measurement of radiolytic products generated as a consequence of irradiation treatment. Additionally, high-field, high-resolution proton nuclear magnetic resonance spectroscopy has been employed to assess radiolytically-induced damage to biomolecules present In shellfish

Specioside (SS) & verminoside (VS) (Iridoid glycosides): isolation, characterization and comparable quantum chemical studies using density functional theory (DFT)

Two biologically important molecules specioside (SS) and verminoside (VS) have been isolated from the ethanolic extract of stem bark of Kigelia pinnata. We have explored the electronic and spectroscopic properties of these two molecules on the basis of the Density Function Theory (DFT) quantum chemical calculations along with the correlations of biological efficacies and the results are presented in this paper. The structures of the molecules were established with the help of spectroscopic techniques (1H, 13C NMR, UV-VIS, FTIR) and chemical reactivity was compared by computed DFT theory using Becke3-Lee-Yang-Parr (B3LYP)/6-31G (d,p) data basis set. UV-Visible spectrum was obtained using Time Dependent DFT method. Electric dipole moment, polarizability, first static hyper polarizability and hyper conjugative interactions were also studied with the aid of natural bond orbital (NBO) analysis of these two compounds. The thermodynamic parameters of these compounds were determined at various temperatures. The HOMO, LUMO, chemical hardness (η), chemical potential (μ), electronegativity (χ), electrophilicity power (ω), the gap energy and NBO analysis of both the compounds have been discussed in this paper. Local reactivity was evaluated through the Fukui function i

Facile Synthesis of Semiconducting Ultrathin Layer of Molybdenum Disulfide

In this paper, we have reported a simple and efficient method for the synthesis of uniform, highly conducting single or few layer molybdenum disulfide (MoS2) on large scale. Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM) have been used for the confirmation of mono or few layered nature of the as-synthesized MoS2 sheets. X-ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD) and Raman Spectroscopy have also been used to study the elemental, phase, and molecular composition of the sample. Optical properties of as-synthesized sample have been probed by measuring absorption and photoluminescence spectra which also compliment the formation of mono and few layers MoS2 Current-voltage (I-V) characteristics of as-synthesized sample in the pellet form reveal that MoS2 sheets have an ohmic character and found to be highly conducting. Besides characterizing the as-synthesized sample, we have also proposed the mechanism and factors which play a decisive role in formation of high quality MoS2 sheets