Volume 14, No. 2 (2013)

OPTIMIZATION OF A UV-VIS SPECTROMETRIC METHOD FOR CAFFEINE ANALYSIS IN TEA, COFFEE AND OTHER BEVERAGES

S. Dobrinas, A. Soceanu*, V. Popescu, G. Stanciu, S. Smalberger

A method has been developed and validated for the determination of caffeine in tea, coffee and other beverages by UV-VIS spectrometry. A linear calibration curve was generated with caffeine concentration ranging from 3 mg∙L-1 to 18 mg∙L-1. The procedure developed provides a 0.85 mg∙L-1 detection limit of caffeine, respectively 1.52 mg∙L-1 quantification limit and the relative standard deviation (RSD) was less than 0.05 % for independent measurement. The developed method was sensitive/specific and robust. Caffeine in tea infusions was found to be dependent on infusion time, the longer of the infusion time and the higher of the caffeine concentrations in tea infusions.

DEGRADATION OF ZEARALENONE BY LACCASE ENZYME

Iuliana Banu*, Anca Lupu, Iuliana Aprodu

The degradation of zearalenone by pure fungal laccase (Trametes versicolor) was investigated in this study. In the experiments different activities of laccase and different initial zearalenone concentrations from liquid medium were used. At 0.4 mg∙mL-1 laccase concentration, after 240 min time of incubation, was obtained an 81.7 % reduction of zearalenone from liquid medium. The zearalenone degradation depends on the initial concentration of mycotoxin and on the activity of laccase. The results obtained can contribute to the development of preventative strategies to reduce mycotoxin contamination of food by involving enzymes.

RESEARCH ON REDUCING THE LENGTH OF MATURATION IN USING ELECTROSTIMULATION OF BEEF

FELICIA DIMA*, CAMELIA VIZIREANU

From technological point of view in the food industry has been obtained meat maturation using different methods: storage under controlled conditions, the use of enzymes or mechanical equipment tenderization musculature. Was also reported that electrical stimulation of carcasses immediately after slaughter procedure can increase the degree of maturation of the meat. Meat and meat products are subjected to reduce during chilling and freezing temperatures principal for reasons of conservation or meat packing. Particular attention must be paid to temperature control, especially before rigor mortis, knowing that too rapid cooling could lead to a cold shortening or thaw rigor during the thaw. During application of the electrostimulation process, occur physical and biochemical changes, meaning that this one has some effect on the technological properties of meat. It has obtained a reduction of maturation of beef with the electrostimulation of half-carcasses of cattle, verified by the increase of non-protein nitrogen in meat. The same time it has been considerably improved the texture and firmness of the muscles, which allows the use of beef in fast food products (ready to cook). Researches have revealed the conclusion that the use of the portable device for electrostimulation, in the described conditions, has induced positive transformations improving meat quality of adult beef.

MANUFACTURE OF BANANA FLAVORED LIQUEURS FABRICATION DES LIQUEURS A SAVEUR DE BANANES

MARIA CRISTIANA GARNAI*, CAMELIA VIZIREANU, FELICIA DIMA

The aim of this study was the obtention of banana flavored liqueurs aromatized with different natural ingredients. For this, different maceration types were compared: maceration of fruit in alcohol (group A), maceration of fruit in sugar (group B) and maceration of fruits in alcohol - sugar mixture (group C). In this work, we also studied the influence of: the variation of the concentration of sugar used for liqueurs (10 % sugar - common liqueurs - and 40 % sugar – fine liqueurs), the variation of the maceration time (7 days and 42 days) and of the addition of different natural ingredients on the liquour flavor. All the liquors were evaluated by a sensory analysis. Performing this study we were able to put in evidence some herbs that can give harmony to the taste of the liquor and can highlight the banana flavor.

SYNTHESIS AND INFRARED STUDY OF SOME NEW MOLYBDATO AND HYDROGENOMOLYBDATO ADDUCTS AND COMPLEXES OF COBALT, ZINC, ANTIMONY AND CADMIUM CHLORIDES

SERIGNE FALLOU POUYE(1), IBRAHIMA CISSE(1*), LIBASSE DIOP(1), LAMINE A. DIOP(2)

Five new molybdato (four) and hydrogenomolybdato (one) adducts and complexes have been synthesized and studied by infrared spectroscopy. The suggested structures are all discrete, the molybdate anion behaving as a trichelating, a monochelating, a bridging, a tetrachelating and a bichelating ligand. The environment around Zn, Co, Cd is tetrahedral or trigonal bipyramidal also for Zn - while being octahedral for Sb. The Cd pentanuclear adduct has a two metallic components structure, a tetranuclear anionic one with a tetrachelating molybdate, the second being a neutral dehydrated adduct component. The suggested structure for the hydrogenomolybdato adduct is discrete, the hydrogenomolybdate being present as a hydrogen bonded dimer behaves as a bridging bidentate ligand. The water molecules can be considered as a coordinating ligand or lattice. When secondary interactions through hydrogen bonds involving the water molecules are considered supramolecular architectures are obtained.

SEPARATION OF WATER VAPORS FROM AIR BY SORPTION ON SOME COMPOSITE MATERIALS

OANA HAUTĂ(*), MARIUS SECULA, IOAN SOLOMON, IOAN MĂMĂLIGĂ

This work presents an experimental investigation of the kinetics of water vapor sorption on two composites synthesized by impregnating activated carbon and activated alumina respectively with lithium bromide (named as MCA2 and MCC2 respectively). The obtained results showed an increase in water amount adsorbed on both composite materials. Due to different chemical natures of the host matrices, the water sorption kinetics on MCC2 is faster compared to that of MCA2. The presence of calcium chloride instead of lithium bromide in alumina pores will determine a shorter breakthrough time and a higher adsorption rate of water vapors.

(Me4N)(NO2)2C6H3CO2 NEW MCl2 (M = Zn, Co, Cd) AND SnR3Cl (R = Me, Ph) ADDUCTS: SYNTHESIS AND INFRARED STUDY

BOCAR TRAORE(1), LIBASSE DIOP(1*), MAMADOU SIDIBE(1)

Five new (Me4N)(NO2)2C6H3CO2 adducts with MCl2 (M = Zn, Co, Cd) and SnR3Cl (R = Me, Ph) have been synthesized and studied by infrared spectroscopy. The suggested structures are discrete, the anion behaving as mono- and bichelating ligand towards MX2, tri- and monodentate towards SnR3Cl (R = Me, Ph).The environment around Zn, Co and Cd is tetrahechal, while the tin (IV) centre is trigonal bipyramidal.

Et2NH2C6H3(CO2)3SnBr2.4H2O: SYNTHESIS AND INFRARED STUDY

DAOUDA NDOYE, LIBASSE DIOP(*)

The title compound has been obtained on allowing [C6H3(CO2)3(Et2NH2)3] to react with SnBr4. The molecular structure of Et2NH2C6H3(CO2)3SnBr2.4H2O has been determined on the basis of the infrared data. The suggested structure is a dimer in which each tin atom is hexacoordinated by two chelating C6H3(CO2)33- anions and two Br atoms. Cy2NH2+cations are involved through hydrogen bonds with non-coordinating CO2 groups. The suggested structure is a cage.