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Fereidoon Shahidi - One of the best experts on this subject based on the ideXlab platform.
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antioxidative activity of chitosans of different viscosity in cooked comminuted flesh of herring clupea harengus
Food Chemistry, 2002Co-Authors: Janak Y V A Kamil, Youjin Jeon, Fereidoon ShahidiAbstract:Antioxidant efficacy of chitosans of different viscosity (14 cP, 57 cP and 360 cP) in cooked, comminuted flesh of herring (Clupea harengus), was investigated. The oxidative stability of treated fish flesh was determined and compared with those treated with conventional antioxidants, such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ) at a level of 200 ppm. The progress of oxidation was monitored by employing the peroxide value, 2-Thiobarbituric Acid-reactive substances (TBARS) and static headspace gas chromatographic analysis. In general, all chitosans exhibited varying antioxidant activities in a fish flesh model system. The formation of hydroperoxides and TBARS, in herring samples containing 200 ppm 14 cP chitosan, was reduced after 8 days of storage by 61 and 52%, respectively. Among the different viscosity chitosans, 14 cP chitosan was more effective than the higher viscosity chitosans in preventing lipid oxidation in the herring flesh model system.
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chemical and stability characteristics of structured lipids from borage borago officinalis l and evening primrose oenothera biennis l oils
Journal of Food Science, 2002Co-Authors: S. P. J. Namal Senanayake, Fereidoon ShahidiAbstract:ABSTRACT: Structured lipids of borage and evening primrose oils containing n-3 fatty Acids were produced via Acidolysis catalyzed by lipase from Pseudomonas sp. The structured lipids were characterized, and their oxidative stability evaluated under Schaal oven conditions at 60 °C by measuring conjugated dienes (CD), 2-Thiobarbituric Acid reactive substances (TBARS) and headspace volatile analysis. Among the oils examined, enzymatically modified products gave rise to higher (p # 0.05) CD, TBARS, and headspace volatiles as compared to those of their unmodified counterparts. Introduction of highly unsaturated fatty Acids and removal of endogenous antioxidants such as tocopherols might be responsible for this observation.
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chitosan as an edible invisible film for quality preservation of herring and atlantic cod
Journal of Agricultural and Food Chemistry, 2002Co-Authors: Youjin Jeon, Janak Y V A Kamil, Fereidoon ShahidiAbstract:The effect of chitosan with different molecular weights as coatings for shelf-life extension of fresh fillets of Atlantic cod (Gadus morhua) and herring (Clupea harengus) was evaluated over a 12-day storage at refrigerated temperature (4 ± 1 °C). Three chitosan preparations from snow crab (Chinoecetes opilio) processing wastes, differing in viscosities and molecular weights, were prepared; their apparent viscosities (360, 57, and 14 cP) depended on the deacetylation time (4, 10, and 20 h, respectively) of the chitin precursor. Upon coating with chitosans, a significant (p ≤ 0.05) reduction in relative moisture losses of 37, 29, 29, 40, and 32% was observed for cod samples coated with 360 cP chitosan after 4, 6, 8, 10, and 12 days of storage, respectively. Chitosan coating significantly (p ≤ 0.05) reduced lipid oxidation as displayed in peroxide value, conjugated dienes, 2-Thiobarbituric Acid reactive substances and headspace volatiles, chemical spoilage as reflected in total volatile basic nitrogen, trime...
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evening primrose meal a source of natural antioxidants and scavenger of hydrogen peroxide and oxygen derived free radicals
Journal of Agricultural and Food Chemistry, 1999Co-Authors: Mahinda Wettasinghe, Fereidoon ShahidiAbstract:Evening primrose meal (EPM: 1% and 2%, w/w) reduced (p ≤ 0.05) the formation of 2-Thiobarbituric Acid-reactive substances (TBARS), hexanal, and total volatiles in cooked comminuted pork by 43.6−72.6%. Phenolic compounds in the EPM were extracted under optimum conditions (with 56% acetone at 71 °C for 47 min) predicted by a multivariate analysis. The resulting evening primrose crude extract (EPCE) inhibited the bleaching of β-carotene in a model system. After 2 h of assay, the system containing 200 ppm EPCE [as (+)catechin equivalents] retained 86% of the initial β-carotene whereas the control retained only 11%. Inhibition of the formation of TBARS, hexanal, and total volatiles in the cooked comminuted pork containing 200 ppm EPCE [as (+)catechin equivalents] ranged from 67.3% to 97.5%. The EPCE inhibited the formation of conjugated dienes, hexanal, and total volatiles in stripped-bulk corn oil (18.5−63.6% inhibition) and stripped-corn oil-in-water emulsion systems (31.7−65.6% inhibition). Hydrogen peroxi...
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stabilization of seal blubber and menhaden oils with green tea catechins
Journal of the American Oil Chemists' Society, 1996Co-Authors: Udaya Nayanakantha Wanasundara, Fereidoon ShahidiAbstract:Catechins, namely (−)epicatechin (EC), (−)epigallocatechin (EGC), (−)epicatechin gallate (ECG) and (−)epigallocatechin gallate (EGCG), were isolated from commercial Chinese green leaves. The antioxidant activity of isolated catechins was compared with those of α-tocopherol, butylated hydroxyanisole (BHA), butylated hydroxytolene (BHT) andtert-butylhydroquinone (TBHQ), all at 200 ppm, in refined, bleached and deodorized seal blubber oil and menhaden oil. The study was carried out under Schaal oven test conditions at 65°C over a 144-h period, except for weight gain measurements, which were continued for up to 200 h. Progression of oxidation was monitored by measuring changes in weight gain and values of peroxide, conjugated diene, and 2-Thiobarbituric Acid-reactive substances. Oils treated with tea catechins showed excellent oxidative stability as compared with samples that contained commonly used antioxidants, such as α-tocopherol, BHA, BHT, and TBHQ. The potency of catechins in prevention of oxidation of marine oils was in the decreasing order of ECG> EGCG> EGC> EC; ECG was slightly more effective than TBHQ in systems studied.
V V Atuchin - One of the best experts on this subject based on the ideXlab platform.
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the cis trans isomer transformation spectroscopic and thermal properties of li na k 1 3 diethyl 2 thiobarbiturate complexes
Polyhedron, 2015Co-Authors: Nicolay N. Golovnev, Maxim S. Molokeev, Irina V. Sterkhova, V V Atuchin, S N VereshchaginAbstract:Abstract Three new complexes of 1,3-diethyl-2-Thiobarbituric Acid (C8H11N2O2S, HDETBA) with Li+, Na+, K+ alkali ions were synthesized. The complexes have been prepared by neutralization of 1,3-diethyl-2-Thiobarbituric Acid with the corresponding metal hydroxide in aqueous solution. The colorless crystals have been investigated using X-ray single crystal and powder techniques and characterized by differential scanning calorimetry, thermogravimetry and infrared spectroscopy. The compounds of MDETBA with M = Li and M = Na crystallize in the monoclinic lattice with a = 10.678(1) A, b = 7.2687(9) A, c = 13.202(2) A, β = 108.841(2)°, Z = 4, V = 969.8(2) A3, S.G. P21/n and a = 10.534(2) A, b = 7.604(1) A, c = 14.186(1) A, β = 108.964(4)°, Z = 4, V = 1074.6(3) A3, S.G. P21/n, respectively. Сompound KDETBA crystallizes in the orthorhombic lattice with a = 4.2541(6) A, b = 14.739(2) A, c = 16.635(3) A, Z = 4, V = 1043.1(3) A3, S.G. P212121. In Li(I) and Na(I) complexes, the DETBA− ion is in cis-configuration and, in the K(I) complex, this ion is in trans-configuration. The reason for the transformation from cis- to trans-configuration has been rationalized.
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the 5 isopropylidene 2 thiobarbituric Acid preparation crystal structure thermal stability and ir characterization
Journal of Molecular Structure, 2014Co-Authors: Nicolay N. Golovnev, Maxim S. Molokeev, Liudmila S Tarasova, V V Atuchin, Natalya I VladimirovaAbstract:Abstract 5-(Isopropylidene)-2-Thiobarbituric Acid (1), C7H8N2O2S, has been crystallized by reacting 2-Thiobarbituric Acid with excessing acetone for 5–6 days under ambient conditions. The pale yellow crystals have been investigated using X-ray single crystal and powder techniques and characterized by differential scanning calorimetry, thermogravimetry and infrared spectroscopy. The compound crystallizes in the monoclinic system with a = 8.8268(19) A, b = 12.044(3) A, c = 8.0998(19) A, β = 105.388(6)°, Z = 4, V = 830.2(3) A3, space group P21/c. The geometric parameters of the heterocycle of the molecule 1 are similar to those found previously for the molecule of thionedicarbonyl tautomer in polymorphic modifications of 2-Thiobarbituric Acid. Infrared spectroscopy also evidences the thionedicarbonyl structure of the 1 heterocyclic ring. Intermolecular N H⋯O hydrogen bonds join the molecules in the chains along b axis. The 1 compound is thermally stable up to 230.0 °С and melts with decomposition at 261.4 °C. The results of mass spectrometric analysis are consistent with the structural parameters found by X-ray diffraction methods.
H Goodarzi - One of the best experts on this subject based on the ideXlab platform.
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electrochemical study of catechol and some of 3 substituted catechols in the presence of 1 3 diethyl 2 thio barbituric Acid application to the electro organic synthesis of new dispirothiopyrimidine derivatives
Journal of Electroanalytical Chemistry, 2001Co-Authors: D Nematollahi, H GoodarziAbstract:Electrochemical oxidation of catechol (1a), 3-methylcatechol (1b) and 3-methoxycatechol (1c) in the presence of 1,3-diethyl-2-Thiobarbituric Acid (3) as a nucleophile in aqueous solution has been studied using cyclic voltammetry and controlled-potential coulometry. The results indicate that (1a–1c) participating in a 1,4 (Michael) addition reaction converts to dispirothiopyrimidine derivatives (6a–6c). The electrochemical synthesis of 6a–6c has been successfully performed in an undivided cell in good yield and purity.
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electrochemical study of catechol and some of 3 substituted catechols in the presence of 1 3 diethyl 2 thio barbituric Acid application to the electro organic synthesis of new dispirothiopyrimidine derivatives
Journal of Electroanalytical Chemistry, 2001Co-Authors: D Nematollahi, H GoodarziAbstract:Electrochemical oxidation of catechol (1a), 3-methylcatechol (1b) and 3-methoxycatechol (1c) in the presence of 1,3-diethyl-2-Thiobarbituric Acid (3) as a nucleophile in aqueous solution has been studied using cyclic voltammetry and controlled-potential coulometry. The results indicate that (1a–1c) participating in a 1,4 (Michael) addition reaction converts to dispirothiopyrimidine derivatives (6a–6c). The electrochemical synthesis of 6a–6c has been successfully performed in an undivided cell in good yield and purity.
S K Hadjikakou - One of the best experts on this subject based on the ideXlab platform.
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structural characterization of polymeric potassium salts with 2 thiobarbituric Acid influence of organotin iv chlorides on potassium cation solvation
Journal of Coordination Chemistry, 2012Co-Authors: Maciej Kubicki, Anita M Owczarzak, Vasilios ι Balas, S K HadjikakouAbstract:Slow evaporation of the filtrate derived from the reaction in water between 2-Thiobarbituric Acid (H2TBA) and equimolar amount of potassium hydroxide results in the formation of crystals of two coordination polymers: unhydrated [K(μ 3-S,O-HTBA)] n (1) and hydrated [K(μ 2-S,O-HTBA)(μ 2-S,O-H2TBA)(μ-H2O)] n (2), which depend on the absence (1) or presence (2) of methanol solutions of organotin chloride. The hydrate 2 was isolated from the filtrates when di-n-butyltin dichloride, dimethyltin(IV) dichloride, diphenyltin(IV) dichloride, tri-n-butyltin chloride, or triphenyltin(IV) chloride were used during the reaction. The crystal structures show that coordination of potassium occurs through the S and O donors. The potassiums have distorted tetragonal bipyramidal and distorted cubic coordination environments in 1 and distorted square antiprism coordination in 2. Both structures exhibit intermolecular N–H ··· O hydrogen-bond interactions, which form TBA chains while the water in 2 produces a richer hydrogen-bo...
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crystal structure and antitumor activity of the novel zwitterionic complex of tri n butyltin iv with 2 thiobarbituric Acid
Bioinorganic Chemistry and Applications, 2008Co-Authors: Vasilios I Balas, S K Hadjikakou, Nick Hadjiliadis, Nikolaos Kourkoumelis, Mark E Light, Michael B Hursthouse, Apostolos Metsios, Spyros KarkabounasAbstract:A novel tri-n-butyl(IV) derivative of 2-Thiobarbituric Acid (HTBA) of formula [(n-Bu)3Sn(TBA) H2O] (1) has been synthesized and characterized by elemental analysis and 119Sn-NMR and FT-IR spectroscopic techniques. The crystal structure of complex 1 has been determined by single crystal X-ray diffraction analysis at 120(2) K. The geometry around Sn(IV) is trigonal bipyramidal. Three n-butyl groups and one oxygen atom from a deprotonated 2-Thiobarbituric ligand are bonded to the metal center. The geometry is completed with one oxygen from a water molecule. Compound 1 exhibits potent, in vitro, cytotoxicity against sarcoma cancer cells (mesenchymal tissue) from the Wistar rat, polycyclic aromatic hydrocarbons (PAH, benzo[a]pyrene) carcinogenesis. In addition, the inhibition caused by 1, in the rate of lipoxygenase (LOX) catalyzed oxidation reaction of linoleic Acid to hyperoxolinoleic Acid, has been also kinetically and theoretically studied. The results are compared to that of cisplatin.
D Nematollahi - One of the best experts on this subject based on the ideXlab platform.
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electrochemical study of catechol and some of 3 substituted catechols in the presence of 1 3 diethyl 2 thio barbituric Acid application to the electro organic synthesis of new dispirothiopyrimidine derivatives
Journal of Electroanalytical Chemistry, 2001Co-Authors: D Nematollahi, H GoodarziAbstract:Electrochemical oxidation of catechol (1a), 3-methylcatechol (1b) and 3-methoxycatechol (1c) in the presence of 1,3-diethyl-2-Thiobarbituric Acid (3) as a nucleophile in aqueous solution has been studied using cyclic voltammetry and controlled-potential coulometry. The results indicate that (1a–1c) participating in a 1,4 (Michael) addition reaction converts to dispirothiopyrimidine derivatives (6a–6c). The electrochemical synthesis of 6a–6c has been successfully performed in an undivided cell in good yield and purity.
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electrochemical study of catechol and some of 3 substituted catechols in the presence of 1 3 diethyl 2 thio barbituric Acid application to the electro organic synthesis of new dispirothiopyrimidine derivatives
Journal of Electroanalytical Chemistry, 2001Co-Authors: D Nematollahi, H GoodarziAbstract:Electrochemical oxidation of catechol (1a), 3-methylcatechol (1b) and 3-methoxycatechol (1c) in the presence of 1,3-diethyl-2-Thiobarbituric Acid (3) as a nucleophile in aqueous solution has been studied using cyclic voltammetry and controlled-potential coulometry. The results indicate that (1a–1c) participating in a 1,4 (Michael) addition reaction converts to dispirothiopyrimidine derivatives (6a–6c). The electrochemical synthesis of 6a–6c has been successfully performed in an undivided cell in good yield and purity.
