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  • Author or Editor: M. Kaur x
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Abstract  

Thermal decomposition of M(mal/fum)�xH2O (M=Mn, Co, Ni) has been studied in static air atmosphere from ambient to 500�C employing TG-DTG-DTA, XRD and IR spectroscopic techniques. After dehydration the anhydrous maleate salts decompose to metal oxalate in the temperature range of 320–360�C, which at higher temperature undergo an abrupt oxidative pyrolysis to oxides. The anhydrous fumarate salts have been found to decompose directly to oxide phase. A comparison of thermal analysis reveals that fumarates are thermally more stable than maleates.

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Physical properties of maize were evaluated as a function of moisture content. The obtained data provide help in the designing of post-harvest handling machinery. In the moisture range of 10–18% wet basis (w.b.), the length of the rewetted grain increased from 10.01 to 10.65 mm, width increased from 8.57 to 8.70 mm, thickness ranged from 4.63 to 4.97 mm, geometric mean diameter (GMD) increased from 7.34 to 7.67 mm, sphericity increased from 0.72 to 0.73, thousand kernel weight (TKW) increased from 258.1 to 287.9 g, bulk density decreased from 591.6 to 554.2 kg m−3, true density increased from 1194.9 to 1267.2 kg m−3, porosity increased from 52.61 to 56.27%, hardness decreased from 293.75 to 228.04 N, initial cracking force decreased from 190.11 to 137.35 N and area ranges from 55.09 to 36.58 Nmm. In the same moisture range the angle of repose varied from 23.36 to 28.55 for grain. Lightness (L) of grain ranges from 62.82 to 59.26, a value (red-green axis) ranges from 13.97 to 8.96, b value (yellow-blue axis) ranges from 31.05 to 26.19 and hue angle (z%) decreased from 14.59 to 14.06 with increase in moisture content of grain from 10 to 18% w.b.

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Summary  

The thermal decomposition of manganese tris(malonato)ferrate(III) hexahydrate, Mn3[Fe(CH2C2O4)3]2 . 6H2O has been investigated from ambient temperature to 600 °C in static air atmosphere using various physico-chemical techniques, i.e., simultaneous TG-DTG-DSC, XRD, Mössbauer and IR spectroscopic techniques. Nano-particles of manganese ferrite, MnFe2O4, have been obtained as a result of solid-state reaction between a-Fe2O3 and MnO (intermediate species formed during thermolysis) at a temperature much lower than that for ceramic method. SEM analysis of final thermolysis product reveals the formation of monodisperse manganese ferrite nanoparticles with an average particle size of 35 nm. Magnetic studies show that these particles have a saturation magnetization of 1861G and Curie temperature of 300 °C. Lower magnitude of these parameters as compared to the bulk values is attributed to their smaller particle size.

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In this study, thirty onion (Allium cepa L.) genotypes grown in sub-tropical region of India were analysed for different physico-chemical attributes. There were significant differences among genotypes, and the onion genotypes showed a tendency to be classified according to different colours. The cultivars of the same colour exhibited similar tendencies in terms of accumulating most of the analysed components. About 1.78 fold variation in dry matter (%) and 2 fold variation in fresh weight per bulb were recorded among coloured onions. Red genotype D-888-B possessed maximum contents of TS and NRS, while the yellow coloured genotype POH-5 accumulated highest RS and lowest NRS contents. Maximum values of fructans (3.68 g/100 g DW), AIS (6 g/100 g DW), protein (10.61 g/100 g DW), and FAA (4.24 g/100 g DW) were also found in red coloured genotypes D-715-B, D-97-B, PR-305, and D-PS-121-B, respectively. Proline content in different genotypes was found to vary about 6.9 fold. The correlation studies showed a positive relationship between most of the quality parameters. Our results suggested that red group genotypes were better than yellow and white groups for all the studied parameters except for RS, which makes red genotypes more suitable for processing purposes.

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Sunflower (PSH 569) was used to obtain textured defatted meal. Proximate analysis, water absorption index (WAI), water solubility index (WSI), fat absorption capacities (FAC), foaming capacity (FC), and bulk density (BD) were determined. The objective of the study was the optimization of extrusion conditions for production of textured defatted sunflower meal using response surface methodology (RSM) by evaluating functional properties. It was dried, grinded, and sieved to eliminate hull and fibre. Numerical optimization provided eight solutions with desirability value varying from 0.81 to 0.82. Range of predicted values of FAC (80.96–90.49), WHC (1.95–2.12), WSI (3.22–3.36), WAI (2.84–3.08), bulk density (0.31–0.36), and foaming capacity (14.39–16.30) were used for numerical optimization. Best extrusion conditions were 16.36% feed moisture, 300 r.p.m. screw speed, and 149.40 °C barrel temperature. Textured sunflower defatted meal was prepared using the above optimized conditions.

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In this study honey samples of Eucalyptus honey (Eucalyptus lanceolatus) were botanically characterized. Response surface methodology was used to analyze the effect of temperature, time and pH on the quality responses (hydroxymethylfurfural concentration and diastatic activity) of Eucalyptus honey. A central-composite rotatable design was used to develop models for the responses. At the central value of time (10 min), the maximum concentration of hydroxymethylfurfural was demonstrated at the highest temperature and pH. The maximum value of hydroxymethylfurfural concentration was also obtained at the maximum time and temperature, while keeping the pH at the central value of 5.3. Diastatic activity decreased as the pH moved away from the central pH value of 5.3 to 5.6 at any level of temperature and time. Three-dimensional response surfaces were superimposed, and the overlapping regions gave the diastatic activity (calculated as diastase number 9 to 23.09 °G) and hydroxymethylfurfural concentration (3 to 10.21 mg kg-1) at 48±1 °C for 9.5±1 min at 5.15±0.15 pH.

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A new, rapid, and specific reversed phase high-performance liquid chromatographic (RP-HPLC) method involving precolumn derivatization with benzoyl chloride was developed and validated for the estimation of γ-aminobutyric acid (GABA) in rat brain tissue preparations. The derivatization product of GABA was identified by melting point, infrared, and proton nuclear magnetic resonance (1H NMR) spectroscopy to be n-benzoyl GABA. Various parameters which influenced derivatization and elusion were optimized. The chromatographic system consisted of C-18 column with ultraviolet (UV)—photodiode array detection ranging from 210 to 400 nm. Elution with an isocratic mobile phase consisting of 0.025 M disodium hydrogen phosphate buffer—methanol (65:35, v/v; pH 6) at a flow rate of 1 mL min−1 yielded sharp and specific peak of n-benzoyl GABA within 7 min. The method was validated with respect to the linearity, accuracy, precision, sensitivity, selectivity, and stability, wherein the benzoyl derivative of GABA showed stability for 2 months. The lower limit of detection was 0.5 nmol L−1. This novel derivatization procedure for the estimation of GABA with benzoyl chloride was also applied for rat brain tissue preparations that gave highly specific peak and good component recovery. The results show that the method for the determination of GABA by benzoylation using RP-HPLC has good linearity, accuracy, precision, sensitivity, and specificity and is simple and economical to perform.

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