Volume 18, No. 4 (2017)
Articles
ALKALI EXTRACTION OF POLYSACCHARIDES FROM PROSO MILLET AND ANTIOXIDANT ACTIVITY
Ai S. Zhu(*), Mao Q. Xu, Jun Z. Zhao
The alkali extraction of polysaccharides from proso millet was investigated by Response Surface Methodology (RSM) based on a three level, four variable Box–Behnken designs in order to obtain an optimal extraction condition combination of alkali concentration, liquid-solid ratio, extraction time, and extraction temperature. The experimental results were fitted to a quadratic polynomial and analyzed. Meanwhile was the antioxidant activity of polysaccharides extracted from proso millet measured in vitro. The results showed that the optimum conditions were alkali concentration 0.87 mol‧L-1, liquid-solid ratio 23.1:1 mL‧g-1, extraction time 1.61 h and extraction temperature 77.7 °C, at this condition combination, the experimental yield of polysaccharides was 38.27 ± 0.35 mg‧g-1, which was very close to the model predicted value of 36.12 mg‧g-1. The quadratic polynomial mathematical model had a good degree of fitting with experimental data (p < 0.0001) and could there out indicate the optimal extraction process conditions. The proso millet polysaccharides were proved by the antioxidant activity experiment to have better radical scavenging activity on superoxide, hydroxyl and DPPH (1,1-Diphenyl-2-picrylhydrazyl).
PHYTOCHEMICAL SCREENING, IN VITRO ANTIOXIDANT AND ANTIBACTERIAL ACTIVITY OF RUMEX VESICARIUS L. EXTRACT
Salah E. Laouini(*), Mohammed R. Ouahrani
Rumex vesicarius L. (Polygonaceae), an edible plant has many important medicinal uses in the southeast of Algeria. The medicinal importance of this plant is a reflection of its chemical composition since the plant contains many bioactive substances. This research investigated the polyphenols profiling (total phenolic content, flavonoids, and condensed tannins), antioxidant and antibacterial properties of ethanolic extracts of seed, flower, leaf and stem from Rumex Vesicarius L. The total phenolic, flavonoid, condensed tannins contents, and antioxidant activity of all the parts extract was quantified. All extracts showed the presence of phenolic compounds and exhibited different levels of free radical scavenging activity against ABTS and superoxide radicals. In addition, for antibacterial activity, the following bacteria were tested: Salmonella typhimurium (ATCC 13311), Escherichia coli (ATCC 35210), Bacillus subtilis (ATCC 10907), Staphylococcus epidermidis (ATCC 12228), Staphylococcus aureus (ATCC 29213) and Pseudomonas aeruginosa (ATCC 27853). Results showed that all extracts possessed concentration-dependent antioxidant activity. The study concludes that Rumex vesicarius L possess diverse therapeutic potentials that might be used as natural antioxidant and antibacterial.
EFFECT OF IMPELLER BLADE THICKNESS ON CRITICAL IMPELLER SPEED IN AN AGITATED VESSEL
Loganathan Muruganandam, Devarajulu Chitra(*)
The successful design and operation of solid-liquid agitators require proper prediction of critical impeller speed (Njs) needed to suspend solids. It depends on system and impeller geometry as well as the properties of both solid and liquid. In this research, the effect of impeller blade thickness on Njs required for complete suspension of solid particles was discussed. Experiments were performed in an agitated vessel of 0.29 m diameter with three impellers namely Rushton turbine (RT), Pitched blade turbine (PBT) and A320 impeller. The impeller thickness was varied as 1, 2, 3 and 4 mm. The results showed that with the increase in impeller blade thickness, the critical impeller speed decreased significantly and the power required for complete suspension increased. Modifications are made in the Zwietering correlation by considering the effect of the impeller blade thickness to improve the prediction of critical impeller speed.
REMOVAL OF NICKEL (II) AND CADMIUM (II) IONS FROM WASTEWATER BY PALM FIBERS
Asma Boudaoud(1*), Mebrouk Djedid(1), Mokhtar Benalia(1), Chifaa Ad(1), Nassira Bouzar(1), Hicham Elmsellem(2)
The palm fibers powder (PFP) was evaluated for the selective removal of nickel (Ni) and cadmium (Cd) from wastewater. The adsorbent was characterized by means of Fourier transform infrared spectrophotometer (FT-IR), X-ray diffraction (XRD) and polarized light microscopy (POM) measurements. The adsorption process was found to be highly pH dependent, facilitating selective adsorption of metals tested. The best Ni (II) and Cd (II) adsorption occurred at an initial concentration of 100 mg‧L-1, 1 g doses of PFP, a temperature of 20 °C, and pH = 5, 6.5 respectively. The maximum sorption capacities obtained with PFP for the studied metal ions were 6.81 mg‧g-1 for Cd (II) at 60 min and 4.42 mg‧g-1 for Ni (II) at 45 min. The adsorption is best fitted in Freundlich isotherm. A comparison of kinetic models (pseudo first-order and the pseudo second-order) at different conditions showed that the pseudo second-order kinetic model correlate the experimental data well. Van’t Hoff equation was used to evaluate the thermodynamic parameters (ΔH°, ΔS°, and ΔG°), which indicate that adsorption process is exothermic in nature, with the absolute values of ΔH° in range of 20-50 kJ‧mol-1 for the two metal ions and the values of ΔS° are found to be -0.142 and -0.062 kJ‧mol-1 for Cd (II) and Ni (II) ions respectively.
DENITRATION OF WASTEWATER GENERATED BY NITROSATION OF ORGANIC COMPOUNDS
Boris M. Laskin, Olesia N. Vozniuk, Dmitrii A. Mukhortov, Arkadiy A. Kossoy, Olga I. Kamskaya, Ilia A. Blinov(*), Marina P. Kambur, Valentin B. Petrov
Subject of the article was to study the method aimed at denitration of liquid wastes that appear during the nitrosation of organic compounds. Liquid waste represents an aqueous solution of sodium sulfate with sodium nitrate and nitrite as admixtures. The method involves addition of sulfuric acid to the wastes followed by drying and thermal treatment of a salt mixture at temperature above 150 °C. Experimental study revealed that sodium nitrite fully decomposes in the solution during the drying resulting in formation of sodium sulfate, nitrogen oxide, and nitrogen dioxide. Solid-phase interaction of sodium hydrogen sulfate and sodium nitrate was investigated by combined DSC-TG technique in the temperature range 100 - 270 °C. The mixture of salts was obtained by drying the aqueous solution. It was shown that the reaction rate is defined by the removal rate of vapors formed nitric acid.
SYNTHESIS OF OXIMES WITH THE DOPED POTASSIUM FLUORIDE ANIMAL BONE MEAL AS A CATALYST
M. Ait Taleb(1,2*), R. Mamouni(1*), N. Saffaj(1), M. Ait Benomar(1), A. Bakka(1), A. Mouna(2), A. Benlhachemi(3), B. Bakiz(3), S. Lazar(4)
The potassium fluoride doped Animal Bone Meal (KF/ABM) was prepared and characterized using several techniques to identify the structural properties. After, it has been used as a new and eco-friendly catalyst for the preparation of from aldehydes and ketones oximes under solvent-free conditions. It is clearly shown that this reaction (using this catalyst) can lead to the corresponding oximes in good yields (80 %) to excellent yields (96 %). In the case of dissymmetric aldehydes and ketones, this catalyst can lead to a mixture of Z- and E- isomers (Z/E = 86/14–90/10). The remarkable advantages of this catalyst are high conversion, short reaction times, cleaner reaction profiles, reusability up to 8 times without significant loss of activity, and reduction in catalyst toxicity.
MAHONIA AQUIFOLIUM AS A PROMISING RAW MATERIAL FOR THE FOOD INDUSTRY
Vladimir N. Sorokopudov(1), Nina I. Myachikova(2), Cecilia Georgescu(3*)
The development of the food industry leads to the expansion of the range of processed raw materials. Mahonia aquifolium today can be attributed to the non-traditional agricultural plants. However, the analysis of the chemical composition of the fruits showed that they contain significant amount of carbohydrates, vitamin C, various minerals, which recommend it for a wider use in the diet. Also due to the presence in the fruits of Mahonia aquifolium anthocyanins can extend of the use as raw material for natural anthocyanin dyes obtaining.
THE EFFECT OF SOXHLET AND ULTRASONIC-ASSISTED EXTRACTION ON ANTIOXIDANT COMPONENTS AND ANTIOXIDANT PROPERTIES OF SELECTED SOUTH ALGERIAN RED POTATOES CULTIVARS
Touhami Lanez(1*), Khaoula Ben Haoua(1,2)
The present work aimed to study the effect of two different commonly applied extraction techniques for the evaluation of total phenolic contents (TPC), total flavonoid contents (TFC) and total antioxidant capacity (TAC) of fresh south Algerian red potatoes cultivars (Solanum tuberosum L). These techniques are namely Soxhlet extraction (SE) and ultrasonic-assisted extraction combines with maceration (UAE-M) for 5 min, 2 hours and 24 hours. A 40 kHz probe was used for the sonication at 3 different amplitudes (30 %, 50 %, and 70 %) with a mixture of ethanol/water at ratios of 70:30 and 100 % v/v as solvent. TPC and TFC obtained using SE are respectively 13.94 mg gallic acid equivalents (GAE) / g extract and 11.32 mg rutin equivalents (RE) / g extract, the amount of these contents is increased to 22.29 mg GAE / g extract and 85.93 mg RE / g extract using UAE-M with 100 % ethanol at amplitude 30 % and 24 hours maceration time. HPLC analysis of samples extract shows four contents with different concentration. In addition, all the results demonstrate a statistically significant with (p < 0.001). It should be noted that the use of UAE-M proved to be faster and more efficient process when compared to Soxhlet extraction.
STUDY OF THE INSERTION AND EXTRACTION MECHANISM OF Li3Mn0.5Ti0.25O3
Jinhe Jiang(1*), Fangwang Liu(2)
The metal oxide [Li3Mn0.5Ti0.25O3] was synthesized by solid state reaction crystallization method in certain temperature. It was an inverse spinel type compound metal oxide. The extraction/insertion reaction of this material was studied by X-ray, saturation exchange capacity value and distribution coefficient (Kd) measurement value. In terms of its composition and chemical metrology, this inverse spinel material is very comprehensive; it is worth noting that it can be inserted or extracted by other substitutional ions and changes in lithium and oxygen stoichiometry while maintaining their crystal structure. The metal oxide [Li3Mn0.5Ti0.25O3] is inorganic Li+ exchanger which has an ion-memory capacity. It has high exchange selectivity ability for Li+. This metal oxide can be used to separate or extract Li+ in aqueous solution. The experimental result has confirmed inverse spinel type compound metal oxide which was treated by acid could attain 9.7 mmol‧g-1 Li+ exchanged capacity.
DEHYDRATION OF CHEESE BY HOT AIR, MICROWAVE AND FREEZE-DRYING
Ana Rita C. Pinho(1), Fernanda R. Assis(1), Ana Paula Peres(2), Manuela E. Pintado(1), Alcina M.M.B. Morais(2*)
The objective of this work was to study the dehydration of skim cheese through different methods, in particular by hot air, microwave and freeze-drying, in order to assess which of these methods would be more suitable for the development of a new product (cheese snack). For the three processes of dehydration, several temperatures, powers and times were used, respectively. The drying time was optimized to allow the water activity of the final product to be between 0.3 and 0.4. The color and texture of the product obtained by the three processes were evaluated, and the nutritional analysis (protein, lipids, ash) of the product dried by hot air at 52 ºC and by microwave at 750 W and 850 W was performed. The sensory analysis of the microwave dehydrated products was also carried out. The results obtained revealed that the temperature played a relevant role in the drying time and the hardness of the product. In the dehydration by microwave, the power of 850 W resulted in a lower drying time and a better color preservation, but in a high hardness of the samples. Among the three processes studied, the microwave drying was the fastest for the water removal from the cheese.