Syed Tufail Hussain Sherazi

Chemical composition, antioxidant and antimicrobial activities of basil (Ocimum basilicum) essential oils depends on seasonal variations.

Chemical composition, antioxidant and antimicrobial activities of the essential oils from aerial parts of basil (Ocimum basilicum L.) as affected by four seasonal, namely summer, autumn, winter and spring growing variation were investigated. The hydro-distilled essential oils content ranged from 0.5% to 0.8%, the maximum amounts were observed in winter while minimum in summer. The essential oils consisted of linalool as the most abundant component (56.7-60.6%), followed by epi-α-cadinol (8.6-11.4%), α-bergamotene (7.4-9.2%) and γ-cadinene (3.2-5.4%). Samples collected in winter were found to be richer in oxygenated monoterpenes (68.9%), while those of summer were higher in sesquiterpene hydrocarbons (24.3%). The contents of most of the chemical constituents varied significantly (p<0.05) with different seasons. The essential oils investigated, exhibited good antioxidant activity as measurements by DPPH free radical-scavenging ability, bleaching β-carotene in linoleic acid system and inhibition of linoleic acid oxidation. Evaluation of antimicrobial activity of the essential oils and linalool, the most abundant component, against bacterial strains: Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pasteurella multocida and pathogenic fungi Aspergillus niger, Mucor mucedo, Fusarium solani, Botryodiplodia theobromae, Rhizopus solani was assessed by disc diffusion method and measurement of determination of minimum inhibitory concentration. The results of antimicrobial assays indicated that all the tested microorganisms were affected. Both the antioxidant and antimicrobial activities of the oils varied significantly (p<0.05), as seasons changed.

Rapid detection of melamine adulteration in dairy milk by SB-ATR-Fourier transform infrared spectroscopy

Melamine is a nitrogenous chemical substance used principally as a starting material for the manufacture of synthetic resins. Due to its very high proportion of nitrogen melamine has been added illegitimately to foods and feeds to increase the measured protein content, which determines the value of the product. These issues prompted private as well as governmental laboratories to develop methods for the analysis of melamine in a wide variety of food products and ingredients. Owing to this fact present study is aimed to use single bounce attenuated total reflectance (SB-ATR) Fourier transform infrared spectroscopy (FTIR) method as an effective rapid tool for the detection and quantification of melamine in milk (liquid and powder). Partial least-squares (PLS) models were established for correlating spectral data to melamine concentration with R(2)>0.99, and RMSEC 0.370. Linear calibration curves were obtained over the calibration range of 25-0.0625%. The LOD and LOQ of the method was 0.00025% (2.5 ppm) and 0.0015% (15 ppm) respectively. Proposed SB-ATR-FTIR method requires little or no sample preparation with an assay time of 1-2 min.

Main fatty acid classes in vegetable oils by SB-ATR-Fourier transform infrared (FTIR) spectroscopy.

The prospect of using single bounce attenuated total reflectance (SB-ATR)-Fourier transform infrared (FTIR) spectroscopy as a rapid quantitative tool to determine the main fatty acid groups present in different edible oils was investigated. Partial least squares (PLS) calibrations were developed using SB-ATR-FTIR spectra which were associated with fatty acid groups (saturated, trans, mono- and polyunsaturated) using quantitative data obtained by gas chromatography (GC). Good calibrations were obtained for all main four fat groups (saturated, mono, trans and polyunsaturated) with excellent precision. The coefficient of determination (R(2)), root mean square error of prediction (RMSEP) and bias for validation set were obtained as 0.999, 2.43 and 0.998 for saturated; 0.999, 1.850 and 0.003 for mono; 0.999, 0.625 and -0.001 for trans while for poly the values were 0.999, 1.170 and 0.003, respectively. The results of 13 validation samples for total saturated, mono, trans and polyunsaturated fats by FI-IR were found in the range of 8.16-55.16, 37.62-74.75, 0.20-18.16 and 1.36-62.35%, respectively. The present study shows that it may well be possible to expand the utility of SB-ATR-FTIR spectroscopy not only to provide isolated trans data, but also serve as a simple, rapid and quantitative means of categorizing the main groups present in the edible oils. The information obtained would be useful for meeting the new lipid nutritional labeling requirements.

GC-MS quantification of fatty acid profile including trans FA in the locally manufactured margarines of Pakistan.

Ten margarine brands of Pakistan were analyzed for their fatty acid composition with emphasis on trans fatty acids (TFA) using GC-MS. Saturated, cis-monounsaturated and polyunsaturated fatty acids were present at 24.2-58.1, 5.7-35.4 and 3.8-37.4% of total fatty acids, respectively. Among the saturated fatty acids, palmitic acid (16.9-33.8%) was dominant in all analyzed margarine brands and its higher amount indicates that palm oil was a major contributor in the margarine manufacturing. Among samples tested only one contained a low level of TFA (2.2%) while the rest contained very high amounts of TFA (11.5-34.8%) which clearly shows that hydrogenated oils were used in the formulation of margarines. Fatty acid profiles demonstrated that all samples belong to the hard margarine category containing high amounts of trans and saturated fatty acids which is an alarming issue for the health of consumers.

Synthesis and application of p-tert-butylcalix[8]arene immobilized material for the removal of azo dyes

The present study describes synthesis of a new resin through immobilization of p-tert-butylcalix[8]arene onto silica and its application for the removal of azo dyes from aqueous media as well as from textile effluents. The newly synthesized material 4 is characterized by FT-IR spectroscopy, scanning electron microscope (SEM) and thermogravimetric analysis (TGA). Reactive Black-5 (RB-5) and Reactive Red-45 (RR-45) azo dyes were used as sorbate. Batch wise sorption experiments were conducted to optimize various experimental parameters such as the effect of sorbent dosage, electrolyte, pH, dye concentration, and contact time. The optimized pH for the effective removal of RB-5 and RR-45 dyes was 9 and 3, respectively. The increase in material 4 dosage increased the percent sorption. Both Langmuir and Freundlich isotherm models were applied to experimental data and Langmuir isotherm model found to be best fit. The results revealed that material 4 was potentially more effective sorbent for the sorption of selected azo dyes as compared to pure silica and p-tert-butylcalix[8]arene. The field studies also supported the effectiveness of material 4, which could be useful for the removal of both the dyes and also for the normalization of pH, TDS, conductivity and salinity near to the drinking water.

Synthesis and application of calix[4]arene based resin for the removal of azo dyes

The present study describes a novel synthetic method for the immobilization of calix[4]arene (II) onto the surface of modified Amberlite XAD-4 resin (4), which does not require the derivatization of calixarene moiety. The novel calix[4]arene based resin (C4 resin) 5 was used as sorbent for the removal of azo dyes. Batch-wise sorption study was carried out and observed that the C4 resin (5) is more effective as compared to compound II as well as pure Amberlite XAD-4 resin (1) to remove the selected dyes [i.e. Reactive Black-5 (RB-5), Reactive Red-45 (RR-45) and Congo Red (CR)]. The effect of sorbent dosage and pH on % sorption was studied. During the extraction process, various kinds of interactions such as electrostatic repulsion, deprotonation of the hydroxyl groups of C4 resin, dissociation of reactive dyes into anions/cations and structural variations were monitored and found that they are highly pH dependent.

Application of microwave heating for the fast extraction of fat content from the poultry feeds.

A rapid method has been developed to extract and quantitatively measure the total oil content in poultry feeds using a domestic microwave oven. The optimized extraction procedure involves the replicate (6x) extraction of 5 g of ground feed with 12 ml of hexane for 20 s in a 900 W oven. Each replicate involves the collection of the resulting miscella and its replacement with fresh solvent for re-extraction. The collected extracts were centrifuged and transferred to a vial. The solvent was evaporated to a constant weight and the residual lipid weighed. In comparison to conventional Soxhlet extraction method, lipid contents obtained using the optimized microwave procedure was not significantly different. However, FTIR analysis indicated that the microwave procedure was superior in minimizing the formation of free fatty acids (FFA) relative to the Soxhlet procedure if the temperature of the sample was kept within the range of 45-50 degrees C. This simple, sequential extraction procedure is rapid, highly efficient and provides a simple mean of quantitating the lipid content of poultry feed in less than 40 min without the need for specialized microwave oven.

Glycine-assisted synthesis of NiO hollow cage-like nanostructures for sensitive non-enzymatic glucose sensing

In this work, a highly sensitive non-enzymatic glucose sensor was developed based on NiO hollow cage-like nanostructures (NiO HCs). The novel nanostructures were synthesized using hydrothermal growth route with glycine employed as an effecient growth director. The synthesized NiO HCs were characterized by using scanning electron microscopy (SEM), X-ray photoelectron microscopy (XPS) X-ray diffraction (XRD) and Fourier transform infrared (FTIR) techniques for morphological, compositional and structural determination respectively. The prepared NiO HCs were directly integrated to be structured electrodes exhibiting enhanced electrocatalytic performance toward the oxidation of glucose with high sensitivity (2476.4 μA mM−1 cm−2), low detection limit (LOD) (0.1 μM), wide detection range (0.1–5.0 mM) (r2 = 0.9997) and excellent reproducibility. The developed non-enzymatic glucose sensor further demonstrated excellent anti-interference property in the presence of common interferents such as uric acid (UA), dopamine (DP) and ascorbic acid (AS). The role of glycine molecules as an efficient growth directing agent with a plausible growth mechanism has also been highlighted. In addition, the NiO HCs modified electrode was also used to analyze glucose concentration in human serum samples. The excellent sensing performance can be attributed to the unique morphology, which allowed increased electron transfer passages with lower charge transfer resistance, and enhanced molecular approach during electrochemical sensing offered from nanoscale “hollow cage” units of NiO structures.

Simultaneous assessment of zinc, cadmium, lead and copper in poultry feeds by differential pulse anodic stripping voltammetry.

In the present work four metals (Zn, Cd, Pb and Cu) were determined simultaneously in 28 commercial broiler poultry feeds by differential pulse anodic stripping voltammetry (DPASV) using hanging mercury drop electrode (HMDE). The digestion of poultry feeds was carried out with concentrated nitric acid and hydrogen peroxide (2:1) with the help of microwave heating. Acetate buffer of pH 5 was used as a supporting electrolyte. The limit of detection for Zn, Cd, Pb and Cu was 0.69, 0.35, 0.68 and 0.24 microg/kg, respectively. The amount of Zn, Cd, Pb and Cu in the analyzed poultry feeds was ranged between 54.3-482.2, 3.8-33.6, 23.2-32.6 and 12.3-65.8 mg/kg, respectively. In most of analyzed poultry feed samples, the amount of Cd and Pb was found to be greater than the maximum tolerable level (MTL) which could be harmful for the poultry.

The removal of organophosphorus pesticides from water using a new amino-substituted calixarene-based magnetic sporopollenin

This study describes the synthesis, characterization and application of a new amino-substituted p-tert-butylcalix[4]arene-based magnetic sporopollenin, Calix-EPPTMS-MS (4), for the removal of two toxic organophosphorus pesticides, namely chlorpyrifos and diazinon, from contaminated water. The synthesized Calix-EPPTMS-MS (4) was characterized using FT-IR spectroscopy, a UV-Vis spectrophotometer, an elemental analyzer, scanning electron microscopy and energy dispersive spectroscopy. The pesticide removal efficiency of Calix-EPPTMS-MS (4) was evaluated through a batch-wise method and gas chromatography using a micro-electron capture detector (GC-μECD). Experimental parameterssuch as adsorbent dosage, pesticide concentration, solution pH and contact time were optimized. Excellent removal efficiencies of 96% for chlorpyrifos and 88% for diazinon were achieved at pH 7 within 10 min of contact time. Kinetic studies showed that both pesticides followed the pseudo-second-order rate model with a coefficient of determination (R2) of 0.999. The Langmuir and Dubinin–Radushkevich isotherms with high values of R2 revealed that chlorpyrifos and diazinon adsorption on the Calix-EPPTMS-MS (4) adsorbent follows the chemisorption mechanism. Pesticide contaminated wastewater samples were used to assess the field applicability of the Calix-EPPTMS-MS (4) adsorbent. The results obtained showed that the newly fabricated adsorbent material Calix-EPPTMS-MS (4) is an efficient adsorbent and exhibits great potential as an alternative adsorbent for pesticide removal.