VOLUME 35, NO1, FEB 2013

Effect of Temperature Variations during Cooking and Storage on Ascorbic Acid Contents of Vegetables: A Comparative Study

Vegetables are generally boiled for cooking or stored in refrigerators. This results in loss of their nutritional values. Ascorbic acid is one of the important nutrients for human health. In this study, Ascorbic acid (vitamin-C) content of various vegetables of Pakistan was determined, and effect of boiling and freezing were compared with natural Ascorbic acid contents by HPLC. The maximum concentration of Ascorbic acid was found in green chilli: i.e. 105 mg /100 g in fresh state; while in boiled and frozen state its concentration is comparatively less: i.e. 85 and 92 mg/100 g respectively. The other vegetables like: cabbage, tomato, turnip, potato, spinach, onion, garlic, green pea, green beans and cauliflower contained greater amount of Ascorbic acid in their fresh state i.e. 30, 20, 25.3, 20, 30, 24.3, 31, 28.5, 30, 42 mg/100 g as compared to frozen (23.4, 13, 23.6, 15, 23.4, 14.1,25, 26.5, 27.0, and 39 mg/100g respectively) and boiled state (11.6, 9.3, 22.5, 10.0, 20.3, 13.1, 23, 25.2 and 35 mg /100g respectively). The minimum amount of Ascorbic acid was found in boiled state of carrot and lettuce: i.e. 4.0 mg/100 g. These results showed that freezing or boiling of vegetables causes significant loss of available Ascorbic acid contents, especially boiling.read more

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WAHEED-UZ-ZAMAN, MEHWISH AKRAM AND RABIA REHMAN

Treatment and Reuse of Wastewater from Beverage Industry

Water is used in most process industries for a wide range of applications. Processes and systems using water today are being subjected to increasingly stringent environmental regulations on effluents and there is growing demand for fresh water. These changes have increased the need for better water management and wastewater minimization. The combination of water demand management and cleaner production concepts have resulted in both economical and ecological benefits. Beverage industry requires huge amount of fresh water, generating considerable amount of polluted waste water during different processes including drink production, washing bottles, plant washdown as well as washing the floors and the general work area. Most of the industries do not reuse the waste water and consuming bulk of fresh water. The beverage industry is one of the major industries in Pakistan and the present study was conducted on the beverage/soft drink industry at Hattar Industrial Estate, Hattar, Pakistan to assess the feasibility of reuse of wastewater form bottle washing plant by conducting treatment test, like dilution of the waste water in different ratios, reverse osmosis and ion exchange.read more

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HAJIRA HAROON, AMIR WASEEM AND QAISAR MAHMOOD

Extraction of Oxytetracycline Hydrochloride in Aqueous Two-phase System of Acetone and Ammonium Sulfate

Aqueous two-phase system (ATPS) is an efficient implement for separation of various substrates, and extracted by an aqueous two-phase system has been successfully applied in the downstream processing of various biological compounds. In this research, the extraction of oxytetracycline hydrochloride (OTC•HCl) was carried out in an aqueous two-phase system containing acetone and ammonium sulfate solution, which partitioned the antibiotic to the upper phase. The effects of some parameters on the extraction efficiency of OTC•HCl were studied in detail, including temperature, the volume of acetone, the pH value of ammonium sulfate solution, the concentrations of (NH4)2SO4 and OTC•HCl. The results showed that the volume of acetone, the pH value of ammonium sulfate solution and the concentration of OTC•HCl in feed had significant effects on the extraction efficiency of OTC•HCl, but the effects of temperature on the extraction of OTC•HCl was not obvious.read more

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JUAN HAN, SHI PING HU, YUN WANG AND JING JING MA

Biocompatible Membranes and Coatings for Glucose Sensor

This paper describes the preparation as well as evaluation of biocompatible membranes and coatings, for an amperometric glucose sensor in order to extend the linear range of the sensor characteristics. For this purpose, both Nafion and polyurethanes are highly suitable, as they increase the upper limit of linearity up to a factor of five. Nafion membranes underwent optimization of their diffusion behavior by temperature-controlled pressing. Sensors with coatings showed much smaller response times (one minute) than with membranes. In both cases, we achieved detection limits of 0.3 mmol/l glucose with a linear sensor characteristic of up to 10 mmol/l compared to 1.4 mmol/l for the unmodified electrodes. Furthermore, polymer coatings and membranes prevent clogging of the sensors by the bioanalytes.read more

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USMAN LATIF, FRANZ LUDWIG. DICKERT, RALPH-GUNTHER BLACH AND HANS-DIETER FEUCHT

Methylene Blue and 4-Chlorophenol Photodegradation Using Gamma-Irradiated Titanium Oxide

This paper presents experiments of heterogeneous photocatalysis of methylene blue and 4-chlorophenol using gamma-irradiated TiO2 with a gamma source of 60Co at different doses. Methylene blue and 4-chlorophenol concentration after photo degradation were measured by UV spectrophotometry. More organic degradation was found using the irradiated catalyst than the non-irradiated catalyst, but a desorption process was noted in samples irradiated at the lower doses.read more

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JAIME JIMÉNEZ-BECERRIL, ALMA MARTÍNEZ-HERNÁNDEZ, FRANCISCO GRANADOS-CORREA AND ROSA E. ZAVALA ARCE

Application of Zwanzig Theory for Different Ions in Pure Solvents at 30°C

The Zwanzig theory of dielectric friction was applied to s- acetylthiocholine halides and perchlorate in different pure solvents at 30°C. The resulting points for the given ions in different solvents were found to be scattered around the straight lines. The scattered values may be attributed to the uncertainty in the values of the relaxation time ( ). The values of the radius from slope (hydrated radius) and intercept (hydrodynamic radius) were increase with increasing the size of ions, while the values of the slope greater than the values of the intercept may be due to the solvation of the ions. Such differences were investigated and discussed on the basis of the assumptions of Zwanzig theory.read more

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MARWA NASR EL-HAMMAMY, NABILA MOHAMED EL-MALLAH, AIDA IBRAHIM KAWANA AND NASR HUSSEIN EL-HAMMAMY

Voltammetric Determination of Sudan II in Food Samples at Graphene Modified Glassy Carbon Electrode Based on the Enhancement Effect of Sodium Dodecyl Sulfate

Herein, a novel electrochemical method was developed for the determination of Sudan II based on the electrochemical catalytic activity of graphene modified glassy carbon electrode (GME) and the enhancement effect of sodium dodecyl sulfate (SDS). In a pH 6.0 phosphate buffer solution, Sudan II exhibited a pair of well-defined quasi-reversible redox peaks at the GME in the presence of 5.0×10-5 mol L–1 SDS. The oxidation peak current of Sudan II was linearly proportional to its concentration in a range from 4.0×10-8 to 4.0×10-6 mol L–1, with a linear regression equation of ipa(A) = 3.35c + 5.96 × 10-6, r = 0.9988 and a detection limit of 8.0×10-9 mol L–1. The recoveries from the standards fortified blank samples were in the range of 94.7% to 97.5% with RSD lower than 4.0%. The novel method has been successfully used to determine Sudan II in food products with satisfactory results.read more

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XINYING MA, MEIFENG CHEN AND MINGYONG CHAO

Stabilize Consequences of Y2O3 in Zirconia Thermal Barrier Coatings (TBC)

The accumulation of cubic stabilizing oxides is a pre-requisite for the use of Zirconia as a main voter in thermal barrier coating. These can be added in ample amounts to form a partially stabilized Zirconia or to form a fully stabilized Zirconia. Zirconia yttria (ZrO2.Y2O3) coating deposited by plasma spray method is widely used in industry as a thermal barrier coating (TBC). Development of narrative and innovative ceramic materials, which have brought about significant hi-tech change, predominately by Y2O3 for the accumulation of varying amounts of cubic stabilizing oxide. This paper is a study on the effect of stabilizer on performance of ZrO2 thermal barrier coatings. For experimentation, Y2O3 complete characterization was done with ZrO2.Y2O3 coated samples to optimize the micro structural, mechanical properties and characterization, using the latest techniques. It was observed that porosity content in all the coated samples was not very high. However the porosity content was uniformly distributed and pore size was small. It has been revealed that, in case of small porosity content, hardness values of thermal barrier coating with stabilizing effect of yttria were not very high.read more

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MUHAMMAD FAROOQ, SHAHZAD ALAM, SHAHZAD NASEEM, SALEEM FAROOQ SHAUKAT AND ROBINA FAROOQ

The Preparation of Ternary Nanocomposite TiO2/ZrO2/SnO2 by Double Template and Application for Water Purification

TiO2/ZrO2/SnO2 nanocomposite with large pore is prepared by sol-gel method with Pluronic P123 and Macrogol 20000 as double template. The structure and physicochemical property of the composite are characterized by small-angle powder X-ray diffraction (SAXS), wide-angle powder X-ray diffraction (WA-XRD) and N2 adsorption-desorption. The photocatalytic efficiencies of the product are assessed by monitoring the photodegradation of Rhodamine B (RhB).The results show that the doping of SnO2 retard the crystal phase transformation from anatase-TiO2 to rutile-TiO2; the doping of ZrO2 stabilizes the anatase phase, and the phase transformation can be greatly retarded; the materials have relatively regular pores and high specific surface area; two types of pores attributed to the usage of double template; the presence of SnO2 significantly increase the degradation rate; the materials can be used five times without decreasing their photocatalytic capacities significantly.read more

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CHUNHUA LU, XIAOYU SUN, JUN PENG AND YUBO MA

RP-HPLC Method Development and Validation for the Simultaneous Estimation of Imidapril HCl and Amlodipine Besylate in Bulk and Tablet

A simple reverse phase liquid chromatographic method has been developed and subsequently validated for simultaneous determination of Imidapril HCl and Amlodipine Besylate in combination. The separation was carried out using a mobile phase consisting of 0.01M potassium dihydorgen phosphate buffer (adjusted with 0.1% phosphoric acid to pH 3.0), acetonitrile and methanol in the ratio of 50: 35: 15. The column used was Lichrospher C18, 5μm, 25 cm × 4.6 mm maintained at 40°C with flow rate of 1 ml / min using PDA detection at 210 and 237 nm for Imidapril HCl and Amlodipine Besylate respectively. The described method was linear over a concentration range of 10-100 μg/ml and 14-140 μg/ml for the assay of Imidapril HCl and Amlodipine Besylate respectively. The retention times of Imidapril HCl and Amlodipine Besylate were found to be 4.3 and 6.7 min respectively. Results of analysis were validated statistically and by recovery studies. The limit of detection (LOD) and limit of quantification (LOQ) for Imidapril HCl and Amlodipine Besylate were found to be 0.13 and 0.28 μg/ml and 0.24 and 1.47 μg/ml respectively. The results of the study showed that the proposed RP-HPLC method is simple, rapid, precise and accurate, which is useful for the routine determination of Amlodipine Besylate and Imidapril HCl bulk drug and in its pharmaceutical dosage form.read more

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MUHAMMAD SAQLAIN TAHIR