Journal of Agricultural and Food Chemistry

Published by American Chemical Society
Online ISSN: 1520-5118
Publications
Article
A procedure for the determination of nitromide in poultry tissue has been developed. The nitromide is extracted from the sample with acetone and chloroform and prepared for chromatography by removing the aqueous phase and evaporating the solvents. The extract residue is then chromatographed on alumina to remove lipid components and residues of other drugs. The benzamide eluate is passed through a column of Dowex-50 resin to remove arylamines (e.g., 3-amino-5-nitrobenzamide), the nitromide fraction is reduced with TiCl 3 to an amine, and the reduced fraction is rechromatographed on another Dowex-50 column. After removal of the interfering substances with washings, the arylamine residue is eluted with 4N HCl. Colorimetric measurement is made in a 100-mm. cell at 530 mμ. after reacting the residue with Bratton-Marshall reagents. Recoveries were in a range from 66.2% for skin to 72.6% for liver and kidney. The interference was less than 0.006 p.p.m. in all tissues and the sensitivity is less than 0.010 p.p.m.
 
Article
Cartilage is a nonedible byproduct with little saleable value, but it is rich in glycosaminoglycan (GAG), which can be converted to a highly profitable product. In this study, GAG was extracted from bovine cartilaginous tissues including nasal cartilage, occipital articular cartilage, and temporomandibular joint disk without using the expensive exogenous proteinase commonly used to extract GAG from tissues. The GAG was extracted with highest yield ( approximately 80% of total tissue uronic acid) by incubating nasal cartilage in 0.1 M sodium acetate, pH 4.5, at 37 degrees C. Tissue autolysis was suggested to occur under the incubation condition to release GAG-peptide. The GAG-peptide purified by DEAE ion-exchange chromatography contained approximately 7% protein, 89% chondroitin sulfate, and 4% keratan sulfate and had no capability to interact with hyaluronic acid. The results suggest that the extraction method with 0.1 M sodium acetate described in this paper is useful for the preparation of GAG-peptide at a low cost.
 
Article
Star Ruby grapefruit [Citrus paradisi (Macf.)] were harvested in November, February, and May, treated with ultraviolet C (UV-C) light at 0.5, 1.5, or 3.0 kJ.m(-)(2), and then stored at 7 degrees C and 90-95% relative humidity (RH) for 4 weeks with 1 additional week at 20 degrees C and approximately 80% RH. Untreated fruits were used as control. UV-C irradiation at 0.5 kJ.m(-)(2) effectively reduced decay development as compared to nontreated fruit without causing damage. Irradiation at dosages >0.5 kJ.m(-)(2) did not further improve decay control and caused rind browning and necrotic peel, the extent of damage depending on treatment dosage and harvest date. The percentage of damaged fruit after irradiation at the higher UV-C dosages was significantly higher in fruit harvested in November; differences between fruits harvested in February and May were negligible. After UV-C irradiation, the phytoalexins scoparone and scopoletin accumulated in flavedo tissue, their amounts depending on harvest date and UV-C dosage. Both phytoalexins showed similar accumulation patterns, although the concentrations of scoparone were much lower than those of scopoletin. Phytoalexin levels increased in most samples as the treatment dosage increased. No detectable levels of scoparone and scopoletin could be found in nonirradiated fruit. The influence of UV-C treatments on soluble solids concentration and titratable acidity of juice was negligible.
 
Article
The soluble fraction (105 000g) from chicken liver homogenates contains an enzyme(s) which metabolizes tetrachlorvinphos. Studies which employed the [14C]vinyl-labeled insecticide indicated that the reaction was glutathione dependent. The primary step was demethylation to desmethyl tetrachlorvinphos, a water-soluble metabolite. It was shown that GSH acts as an acceptor for the transferred methyl group to form S-methylglutathione. The soluble fraction contains enzymes other than glutathione S-alkyltransferase. The polar fraction was further metabolized to benzene extractable compounds which were identified as 2,4,5-trichloroacetophenone, 1-(2,4,5-trichlorophenyl)ethanol and 2-chloro-1-(2,4,5-trichlorophenyl)ethanol.
 
Article
This study was performed to discover bifidobacteria isolated from human intestines that optimally convert linoleic acid (LA) to conjugated linoleic acid (CLA) and to optimize the culture conditions of milk fermentation. One hundred and fifty neonatal bifidobacteria were screened for CLA-producing ability, and Bifidobacterium breve LMC 017 was selected as it showed about 90% conversion of free LA in MRS broth. The selected strain showed resistance at 0.5% LA in microaerophillic conditions. When monolinolein (LA 90%) was used as a substrate for CLA production, the conversion rate was lower compared to free LA, but the growth rate was unaffected during the milk fermentation. There was no significant difference in CLA production between aerobic and anaerobic conditions, and little decline in CLA was shown after the maximal CLA level had been reached. CLA production increased by 80% with 24 h of incubation in milk containing additional skim milk (5%), where the proteins may have facilitated the production of CLA by enhancing the interaction of substrate with the bacteria. CLA production did not decline after 9 h of fermentation and an additional 12 weeks of storage with other commercial starters. This demonstrates the possibility of using this strain as a costarter in the production of CLA-enriched yogurt.
 
Article
The widely used insecticide fenpropathrin in agriculture has become a public concern because of its heavy environmental contamination and toxic effects on mammals, yet little is known about the kinetic and metabolic behaviors of this pesticide. This study reports the degradation kinetics and metabolic pathway of fenpropathrin in Bacillus sp. DG-02, previously isolated from the pyrethroid-manufacturing wastewater treatment system. Up to 93.3% of 50 mg L(-1) fenpropathrin was degraded by Bacillus sp. DG-02 within 72 h, and the degradation rate parameters qmax, Ks, and Ki were determined to be 0.05 h(-1), 9.0 mg L(-1), and 694.8 mg L(-1), respectively. Analysis of the degradation products by gas chromatography-mass spectrometry led to identification of seven metabolites of fenpropathrin, which suggest that fenpropathrin could be degraded first by cleavage of its carboxylester linkage and diaryl bond, followed by degradation of the aromatic ring and subsequent metabolism. In addition to degradation of fenpropathrin, this strain was also found to be capable of degrading a wide range of synthetic pyrethroids including deltamethrin, λ-cyhalothrin, β-cypermethrin, β-cyfluthrin, bifenthrin, and permethrin, which are also widely used insecticides with environmental contamination problems with the degradation process following the first-order kinetic model. Bioaugmentation of fenpropathrin-contaminated soils with strain DG-02 significantly enhanced the disappearance rate of fenpropathrin, and its half-life was sharply reduced in the soils. Taken together, these results depict the biodegradation mechanisms of fenpropathrin and also highlight the promising potentials of Bacillus sp. DG-02 in bioremediation of pyrethroid-contaminated soils.
 
Article
Four strains of probiotics were evaluated for their alpha-galactosidase activity. Lactobacillus acidophilus FTCC 0291 displayed the highest specific alpha-galactosidase activity and was thus selected to be optimized in soy whey medium supplemented with seven nitrogen sources. The first-order model showed that meat extract, vegetable extract, and peptone significantly (P < 0.05) influenced the growth of L. acidophilus. The second-order polynomial regression estimated that maximum growth was obtained from the combination of 7.25% (w/v) meat extract, 4.7% (w/v) vegetable extract, and 6.85% (w/v) peptone. The validation experiment showed that response surface methodology was reliable with a variation of only 1.14% from the actual experimental data. Increased utilization of oligosaccharides and reducing sugars contributed to increased growth of L. acidophilus in the soy whey medium. This was accompanied by increased production of short-chain fatty acids and a decrease in pH.
 
Article
A gas chromatographic method is described for the determination of D-048 [1-(2-butynyl)-1-(p-tert-butylphenoxy)-2-butyl sulfite] residues in cottonseed, cottonseed meal, and cottonseed oil. After extraction and cleanup by acetonitrile partition and Florisil column chromatography, D-048 is identified using a flame photometric detector in the sulfur mode. Recovery of D-048 averaged 91 ± 9% from the various cottonseed samples fortified at levels ranging from 0.1 to 1.0 ppm. The method is sensitive to 0.2 ppm for cottonseed oil and 0.1 ppm for cottonseed and cottonseed meal.
 
Article
This study focused on the cloning, overexpression and characterization of the gene encoding L-asparaginase (ansZ) from a non-pathogenic strain of Bacillus subtilis B11-06. The recombinant enzyme showed high thermostability and low affinity to L-glutamine. The ansZ gene, encoding a putative L-asparaginase II, was amplified by PCR and expressed in B. subtilis 168 using shuttle vector pMA5. The activity of the recombinant enzyme was 9.98 U/mL, which was significantly higher than that of B. subtilis B11-06. The recombinant enzyme was purified by a two-step procedure including ammonium sulfate fractionation and Hydrophobic Interaction Chromatography. The optimum pH and temperature of the recombinant enzyme were pH 7.5 and 40°C, respectively. The enzyme was quite stable at a pH range of 6.0-9.0, and exhibited about 14.7% and 9.0% retention of activity following 2 h incubation at 50°C or 60°C, respectively. The Km for L-asparagine was 0.43 mM and Vmax was 77.51 μM/min. Results of this study also revealed the potential industrial application of this enzyme in reducing acrylamide formation during the potato frying process.
 
Article
1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of Japanese whiskey after various aging periods in oak barrels was measured to evaluate the antioxidative effects of whiskey. The activity of the whiskey increased with the aging period with high correlation. The activity of various types of whiskey was measured and shown to be correlated to the potentiation of the GABAA receptor response measured in a previous paper. However, the fragrant compounds in the whiskey which potentiated the GABAA receptor response had low DPPH radical scavenging activity, while phenol derivatives had high radical scavenging activity. The whiskey was extracted by pentane. The aqueous part showed the scavenging activity, whereas the pentane part did not. Thus, both the DPPH radical scavenging activity and the potentiation of the GABAA receptor response increased during whiskey aging in oak barrels, but were due to different components. The whiskey protected the H2O2-induced death of E. coli more than ethanol at the same concentration as that of the whiskey. The changes that occurred in the whiskey during aging may be the reason aged whiskies are so highly valued.
 
Article
Thirty-four kinds of citrus essential oils and their components were investigated for radical-scavenging activities by the HPLC method using 1,1-diphenyl-2-picrylhydrazyl (DPPH). To examine the oils' relative radical-scavenging activities compared with that of a standard antioxidant, Trolox was employed. All of the essential oils were found to have scavenging effects on DPPH in the range of 17. 7-64.0%. The radical-scavenging activities of 31 kinds of citrus essential oils were comparable with or stronger than that of Trolox (p < 0.05). The oils of Ichang lemon (64.0%, 172.2 mg of Trolox equiv/mL), Tahiti lime (63.2%, 170.2 mg of Trolox equiv/mL), and Eureka lemon (61.8%, 166.2 mg of Trolox equiv/mL) were stronger radical scavengers than other citrus oils. Citrus volatile components such as geraniol (87.7%, 235.9 mg of Trolox equiv/mL), terpinolene (87.4%, 235.2 mg of Trolox equiv/mL), and gamma-terpinene (84.7%, 227.9 mg of Trolox equiv/mL) showed marked scavenging activities on DPPH (p < 0.05).
 
Article
The effect of sunlight on dilute aqueous solutions of 3-(p-chlorophenyl)-1,1-dimethylurea (monuron) was examined, and a special photoreactor was utilized to simulate the outdoor exposure. Photoproducts were separated by thin-layer chromatography; 3 - (p - chlorophenyl) - 1 - formyl - 1 - methylurea, 1 - (p - chlorophenyl) - 3 - methylurea, 4,4′ - dichlorocarbanilide, and 3 - (4 - chloro - 2 - hydroxyphenyl)-1,1-dimethylurea were verified by the identities of their infrared and mass spectra with those of the synthesized standards. 1-(p-Chlorophenyl)-3-formylurea, 4′-chloroformanilide, and p-chloroaniline were tentatively identified by co-chromatography with the authentic compounds in several solvent systems. The principal pathways of monuron photodecomposition were found to be stepwise photooxidation and demethylation of the N-methyl groups, hydroxylation of the aromatic nucleus, and polymerization.
 
Article
This study investigates a semicontinuous hot pressurized fluid extraction process and the scavenging activity on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical of the extract from Taiwan yams (Dioscorea alata). Liquid-liquid extractions were preliminarily employed to generate six fractions, initially extracted by ethanol. Then, the aqueous solution of dried crude ethanol extract was sequentially fractionated by hexane, chloroform, ethyl acetate, and n-butanol. The EC50 value was defined as the UV absorption of DPPH concentrations sufficiently decreased to 50% of the original value. It was found that all peel portions have a better effect on scavenging of the DPPH free radical than meat portions, especially for the ethyl acetate partition of the peel portion of Tainung #2 yam. Its EC50 value (14.5 microg mL(-1)) was even lower than that of ascorbic acid (21.4 microg mL(-1)). Furthermore, semicontinuous hot pressurized ethanol was superior to hot pressurized water in extracting the compound scavenging the DPPH radical from the Purpurea-Roxb peel. The recovery of four unknown compounds corresponded to the scavenging ratio of DPPH free radical in the hot pressurized ethanol extract. Finally, three-level and four-factor experimental design revealed that ethanol ratio and temperature were the most effective factors in order. Conditions of 80% of aqueous ethanol, 20.0 kg/kg solid ratio, 180 psig (1.342 MPa), and 100 degrees C were preferred to extract those antioxidants from the yam peel.
 
Article
(+)-catechin, ethyl gallate, ascorbic acid, and alpha-tocopherol were reacted with 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the reaction mixtures were subjected to 13C-nuclear magnetic resonance (NMR) analyses to clarify the molecular mechanisms of the antioxidative and radical-scavenging activities of each antioxidant. When ascorbic acid was reacted with DPPH, it was oxidized to dehydroascorbic acid by DPPH. When a mixture of ascorbic acid and (+)-catechin was reacted with DPPH, ascorbic acid scavenged DPPH radical faster than (+)-catechin. Ascorbic acid also scavenged DPPH radical faster than ethyl gallate and alpha-tocopherol. When (+)-catechin was reacted with DPPH, the B-ring of (+)-catechin changed to an o-quinone structure. However, it was reduced to (+)-catechin by ethyl gallate or alpha-tocopherol. alpha-Tocopherol and ethyl gallate had almost identical antioxidative activities. Therefore, the order of radical-scavenging ability (speed) suggested by our 13C NMR study was as follows: ascorbic acid > alpha-tocopherol = ethyl gallate > (+)-catechin.
 
Article
Tea (Camellia sinensis) leaves contain various antioxidants such as ascorbic acid (1) and polyphenols. This study tries to clarify the molecular mechanisms underlying the antioxidative and radical-scavenging activities of these antioxidants, and the reactivities of each antioxidant have been compared against that of the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH, 2) using nuclear magnetic resonance (NMR) analysis. Catechol (3) and (+)-taxifolin (4) were oxidized to o-quinone by 2. However, ethyl protocatechuate (5) and quercetin (6) were not oxidized to o-quinone, even though they possess a catechol structure. The radical-scavenging ability of o-dihydroxyl phenolic compounds with a conjugated olefinic double bond (e.g., 6) was superior to that of compounds without this bond (e.g., 4), whereas the ability of o-dihydroxyl phenolic compounds possessing a conjugated carbonyl bond (5) was inferior to that of compounds lacking this bond (3). Vicinal trihydroxyl phenolic compounds with a conjugated olefinic double bond [e.g., myricetin (7)] had an inferior scavenging ability as compared with compounds lacking this bond [e.g., pyrogallol (8)], but 7 was a better scavenger than compounds with a conjugated carbonyl double bond [e.g., ethyl gallate (9)]. In addition, vicinal trihydroxyl phenolic compounds (e.g., 9) were superior to o-dihydroxyl phenolic compounds (e.g., 6). Finally, 1 scavenged radicals more quickly than 8.
 
Article
Each tea catechin was reacted with 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the reaction mixture was subjected to NMR analysis. The antioxidation mechanism of (+)-catechin [(+)-C] is considered to be due to the change of the B-ring to an o-quinone structure at first because of the appearance of two carbonyl signals. This is substantiated by trapping the compound as an adduct of a 1,2-phenylenediamine to an o-quinone. (-)-Epicatechin [(-)-EC] was also confirmed to give a similar result, but in the case of (-)-epigallocatechin [(-)-EGC] and ethyl gallate (EG) no carbonyl signals were observed. The antioxidation mechanisms of (-)-EGC and EG are different from those of (+)-C and (-)-EC. This may be one of the reasons for the differences of the antioxidative activities between the two types of catechins.
 
Article
Rainbow trout and squawfish were exposed to the selective piscicide Squoxin (1,1′-methylenedi-2-naphthol) in the laboratory, using the tritiated compound, and in the field using a commercial formulation. Laboratory exposures were at concentrations of 50 ppb, the exposures repeated as many as four times in the case of the trout. Radioassays of whole body and certain tissues and organs of the trout immediately after exposure and after fresh water purges up to 8 days showed that there was no tendency for the piscicide to beretained. Maximum residues, based on the radioassays, were equivalent to 9.45 ppm. of Squoxin. in the trout. Squawfish, killed by a single exposure, had maximum residues, as Squoxin, of 3.50 ppm. The field-treated fish were exposed to Squoxin at a concentration of 100 ppb. Analyses were by gas chromatography. Surviving trout contained residues as high as 1.48 ppm (whole body), while dead squawfish contained residues ranging from 0.84 to 2.38 ppm. Residues in the edible tissues of the trout were less than 0.1 ppm.
 
Article
Results of a study of the metabolic products identified in rat and cow urine and rat feces from oral ingestion of the new herbicide N-(1,1-dimethyl-propynyl)-3,5-dichlorobenzamide (Compound A) are presented. Half the radioactivity in rat feces and less than 1 % in rat urine was unchanged Compound A. Cow urine contained no Compound A. In rat feces the metabolites were: 2-(3,5-dichlorophenyl)-4,4-dimethyl-5-methyleneoxazoline (I), N-(1,1-dimethylacetonyl)-3,5-dichlorobenzamide (II), 2-(3,5-dichlorophenyl)-4,4-dimethyl-5-hydroxymethyloxazoline (III), N-(1,1-dimethyl-3-hydroxyacetonyl)-3,5-dichlorobenzamide (IV), N-(1,1-dimethyl-3-hydroxypropyl)-3,5-dichlorobenzamide (V), N-(1,1-dimethyl-2,3-dihydroxy-propyl)-3,5-dichlorobenzamide (VI), β-(3,5-dichlorobenzamido)-β-methylbutyric acid (VII), α-(3,5-dichlorobenzamido)isobutyric acid (VIII), plus one metabolite which has not been identified. In rat urine the metabolites were III, IV, VI, VII, VIII, plus β-(3,5-dichlorobenzamido)-α-hydrpxy-β-methylbutyric acid (XII), and three unidentified metabolites different from that found in the feces. In cow urine the metabolites were VII, VIII, XII, and one of the unidentified metabolites found in rat urine. A tentative pathway by which these metabolites may have been formed is discussed.
 
Article
Groups of dairy cows and laying hens were fed specially prepared diets containing alfalfa with field-aged residues due to the herbicide 3,5-dichloro-N-(1,1-dimethyl-2-propynyl)benzamide. Residues greater than 0.01 ppm were found only in milk from cows fed 7.5 ppm of herbicide residues and in eggs from chickens fed 1.8 ppm of herbicide residues. No evidence for a continual accumulation of residues was observed in either eggs or milk. Detectable residues were found only in cow liver and kidney, and hen liver, kidney, gizzard, and fat.
 
Article
Four phenolic metabolites of p,p' DDE were identified in rat feces after dosing with p,p' DDE. The structures of the metabolites, 2 hydroxy 4,4' DDE, 3 hydroxy 4,4' DDE, 4 hydroxy 3,4' DDE, and 4 hydroxy 4' DDE, were ascertained by spectral and chromatographic comparisons with synthetic material. Two of the metabolites show structures which suggest the initial formation of an arene oxide in the metabolic process.
 
Article
Procedures are given for the measurement of the piscicide 1,1′-methylenedi-2-naphthol (Squoxin) in fish tissue, using gas chromatography, and in water, using a colorimetric method. For the GC method, Squoxin is converted to its dimethyl ether and detected by electron capture. The method is sensitive to 0.1 ppm of Squoxin in fish tissue. The second method, which is designed for use in the field, involves coupling the piscicide with the chromogenic agent, tetrazotized o-dianisidine (Diazo Blue B). With the use of extraction and concentration steps this method is sensitive to 2 ppb of Squoxin in water. The two methods have been used in the analysis of fish and water samples from field tests of Squoxin.
 
Article
Spinning cone column (SCC) distillation has been shown to be a commercially suitable technique for dealcoholized wine (DW) manufacturing, but there are not enough studies about its influence on the DW quality. So, the effect of this technique on the antioxidant activity (% of remaining 1,1-diphenyl-2-picrylhydrazyl radical) and the phenolic compound composition of red, rose, and white DW, obtained at pilot plant scale, has been analyzed. Nineteen raw wines (RWs) from different grape varieties and five different Spanish viticultural regions have been studied before and after dealcoholization. The total phenolic content, flavonols, tartaric esters, and anthocyanins, was determined by spectrophotometry, while the content of phenolic compounds such as stilbenes (trans- and cis-resveratrol), flavonols (rutin, quercetin, and myricetin), flavan-3-ols [(+)-catechin and (-)-epicatechin], anthocyanins (malvidin 3-glucoside), and non-flavonoids (gallic, caffeic, and p-coumaric acids) was determined by high-performance liquid chromatography (HPLC). The resveratrol contents in red wines were between 1.81 and 34.01 mg/L in RWs and between 2.12 and 39.57 mg/L in DWs, Merlot being the grape producing the RWs and DWs with higher resveratrol content. In general, the percent of remaining DPPH(*) was similar or slightly higher (until 5 units of % of remaining DPPH(*)) in DWs versus RWs. This small difference may be due to removal of SO2 (that is an antioxidant) from RWs during distillation. DWs and RWs show similar contents of the studied phenolic compounds, with a tendency, in some cases, to exhibit increases after dealcoholization, caused by the concentration effect via removal of the ethanol. From this work, we can deduce that SCC distillation is a dealcoholization technique minimally destructive with the wine phenolic compounds.
 
Article
Free radical-scavenging activity of isoflavones and some isoflavone metabolites have been described previously, but the results are inconsistent. The objective of the present study was to find out the pivotal factors that influence an accurate detection of both superoxide anion and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity. We here showed for the first time that organic solvents, including methanol, ethanol and acetone, were of strong superoxide radical-scavenging activity at concentrations down to 0.1% (v/v), however, no such activity was observed with acetonitrile at concentrations up to 2.0% (v/v). In DPPH assay, we found that the DPPH radical-scavenging ratio increased together with the extended reaction time. Based on our findings, improved in vitro assays for the detection of radical-scavenging activity of both isoflavones (daidzein and genistein) and isoflavone metabolites, including dihydrodaidzein (DHD), dihydrogenistein (DHG), and O-desmethylangolensin (O-Dma), were established.
 
Article
The herbicide 3-(p-chlorophenyl)-1,1-dimethylurea (mpnuron) was photolyzed under anaerobic conditions in methanol and was found to react cleanly to form the dechlorinated herbicide 3-phenyl-1,1-dimethylurea (fenuron). Methyl p-chlorophenyl-carbamate was obtaine4 as a minor product. Photolysis of 3-phenyl-1,1-dimethylurea (fenuron) afforded aniline, o-amino-N,N-dimethylbenzamide, and p-amino-N,N-dimethylbenzamide. All products were isolated and identified by comparison with authentic materials.
 
Article
Results of a study of the metabolism of the new herbicide N-(1,1-dimethylpropynyl)-3,5-dichlorobenzamide (Compound A) in soil and alfalfa using C14-labeled compound are presented. In soil, Compound A is readily cyclized to 2-(3,5-dichlorophenyl)-4,4-dimethyl-5-methyleneoxazoline, which is subsequently hydrolyzed to N-(1,1-dimethylacetonyl)-3,5-dichlorobenzamide. Several other metabolites are also formed, including 2-(3,5-dichlorophenyl)-4,4-dimethyl-5-hydroxymethyloxazoline, N-(1,1-dimethyl-3-hydroxyacetonyl)-3,5-dichlorobenzamide, N-(1,1-dimethyl-3-hydroxypropyl)-3,5-dichlorobenzamide, N-(1,1-dimethyl-2,3-dihydroxypropyl)-3,5-dichlorobenzamide, β-(3,5-dichlorobenzamido)-β-methylbutyric acid, α-(3,5-dichlorobenzamido)iso-butyric acid, and β-(3,5-dichlorobenzamido)-β-methyl-α-ketobutyric acid. When applied by foliar application to alfalfa, the rate of metabolism is slow, but most of the metabolites formed in the soil can be identified in the plant.
 
Article
In vitro biotransformations of 14C-labeled 1-(o-chlorophenyl)-1-(p-chlorophenyl)-2,2-dichloroethane (o,p′-DDD) and 1,1-bis(p-chlorophenyl)-2,2-dichloroethane (p,p′-DDD) by bovine adrenal homogenates were studied. Homogenates were found to oxidize o,p′-DDD to o,p′-dichlorodiphenylacetic acid (o,p′-DDA), while p,p′-DDD was converted to bis(p-chlorophenyl)acetic acid (p,p′-DDA) and 1,1-bis(p-chlorophenyl)-2,2-dichloroethanol. Transformation products were identified by thin-layer chromatography and mass spectra of band extracts. The mitochondrial fraction was found to be the most active of the cortex subcellular fractions in transforming the substrates with some contribution by the soluble fraction. Transformation by the microsomal fraction was negligible. An NADPH generating system was necessary for these transformations, and they did not occur with boiled enzyme preparations.
 
Article
Free radical scavenging reactions of green tea polyphenols (GTP) were investigated with electron spin resonance (ESR) spectroscopy in the phospholipid bilayer of liposomes, using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical as a model. The results showed that (1) GTP reacts with DPPH radicals in the bilayer of liposomes of both 1-hexadecanoyl-2-[(cis,cis,cis,cis,cis,cis)-4,7,10, 13,16,19-docosahexaenoyl]-sn-glycero-3-phosphocholine (DHAPC) and 1, 2-di[cis-9-hexadecenoyl]-sn-glycero-3-phosphocholine) (DPPC); and (2) GTP protects DHAPC liposomes effectively from the oxidation initiated by DPPH radicals. These results provide direct evidence that GTP reacts with free radicals in the model membrane and support the hypothesis that GTP protects unsaturated phospholipids from oxidation by reacting directly with the radicals.
 
Article
Forty-three percent of the bacteria isolated from sea water and marine sediments converted between 5 and 10% of the DDT supplied in vitro to water-soluble products, and 35% transformed less than 5% of the insecticide to water-soluble metabolites. Several water-soluble compounds generated from DDT by Mucor alternans were partially characterized and were found to be different from known products of DDT metabolism. However, the insecticide was not converted to water-soluble products in model marine ecosystems supplemented with a large number of organic compounds and incubated aerobically, anaerobically, and with supplemental inorganic nutrients.
 
Article
Naturally contaminated beef samples containing 5 and 8 ppm of total DDT (DDE, DDD, and DDT) were processed and cooked by two different methods. Both processing methods (104°C, 137 min; 126.7 °C, 66 min) reduced total DDT in the fat of beef. A mean loss of 20% occurred in fat below tolerance and a 10% loss in the fat above the tolerance level. Cooking by microwaves or in a conventional oven resulted in a 17% further loss.
 
Article
Thirty-seven analogues of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its metabolites were tested for their susceptibility to biodegradation by means of the biological oxygen demand technique. Of the diphenylmethanes, benzhydrols, benzophenones, and phenylacetates tested, the unsubstituted chemicals and those with a single hydroxyl, amino, or methoxy group in the para position were readily metabolized by soil microorganisms. Chemicals with hydroxyl, chlorine, or methoxy groups in both para positions were resistant to biodegradation.
 
Article
Swiss mice and Syrian golden hamsters were fed 250 μg/g of dietary DDT for up to 4 months and urinary and fecal metabolites were investigated. Both species excreted the base labile glucuronide of bis(p-chlorophenyl)acetic acid (DDA) as the principal urinary metabolite. The more stable glycine and alanine conjugates of DDA were also found. The mouse differed from the hamster in excreting DDE in the urine. The excretion of DDE increased during the course of the experiment until in the fourth month it was nearly as prominent as DDA. Endogenously formed cinnamoylglycine was also excreted by the mouse in amounts that increased upon DDT administration. The feces of both species contained DDD and DDT. Fecal excretion was not an important route for the elimination of polar DDT metabolites in these animals.
 
Article
Toxaphene at the rate of 200 to 267 mg/m2 (2 to 2.7 kg/ha) and DDT at 100 to 133 mg/m2 (1 to 1.3 kg/ha) were applied to cotton plants at weekly intervals for 6 weeks in an enclosed chamber (agro-ecosystem) and the residues monitored for 90 days. Twenty-four percent of the toxaphene and 15% of the DDTR (p,p′-DDE, p,p′-DDD, p,p′-DDT, and o,p′-DDT) volatilized and 20 and 24%, respectively, was found in the surface 1-cm soil. Most of the insecticide residues volatilized within 24 h from 18.9, 7.3, and 0.4 mg/m2 per day (189, 73, and 4 g/ha per day) on days 1, 3, and 56 for toxaphene and 6.5, 1.8, and 0.2 mg/m2 per day (65, 18, and 2 g/ha per day) for DDTR. Volatilization losses were insignificant, <0.1 mg/m2 per day (<1 g/ha per day) , for both toxaphene and DDTR after 90 days. Volatilization losses for both insecticides seemed to follow log concentration with log time the first week and then log concentration with linear time thereafter. Calculated first-order equation half-lives for volatilization of toxaphene, p,p′-DDT, o,p′-DDT, and p,p′-DDE were 15.1, 18.8, 14.3, and 15.1 days, respectively. On dry cotton leaves, toxaphene residues ranged from about 4000 to 700 ppm (100 to 18 mg/m2) from application to 56 days, and DDTR residues ranged from about 2000 to 380 ppm (50 to 10 mg/m2), respectively, for the same period.
 
Article
Pseudomonas putida, an organism capable of utilizing diphenylmethane and benzhydrol as sole sources of carbon, cometabolized bis(p-chlorophenyl)methane (DDM) to p,p′-dichlorobenzhydrol (DBH), p,-p′-dichlorobenzophenone (DBP), benzhydrol, benzophenone, p-chlorophenylacetic acid, and p-chlorophenylglycolaldehyde. DBH was converted by the resting cells to DBP, benzhydrol, and benzophenone. No products were detected when the bacterium was incubated with DBP. Bis(p-chlorophenyl)acetic acid was cometabolized to DDM, DBH, and DBP. The addition of diphenylmethane to the resting cells did not stimulate the cometabolism of DDM, and no new chlorinated products were detected when the bacteria were provided with both substrates. 1,1,1′,1′-Tetra(p-chlorophenyl)dimethyl ether was not formed microbiologically from either DDM or DBH.
 
Article
Chloral hydrate and DDT, present in low concentrations in aqueous media, are dechlorinated by moderate doses of γ-radiation. Oxygen and relatively high concentrations of organic material reduce, but do not completely inhibit, chloral hydrate dechlorination.
 
Article
Raw and processed samples of ground beef containing naturally occurring residues of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its metabolites were compared with the same ground beef to which an ethanol-water solution of p,p′-DDT had been added. Two treatments, a 104 ° steritort process for 342 min and broiling patties for 4 min on each side, were found to cause different losses of pesticides. No difference existed between method of heating with respect to 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) in nonspiked or spiked samples. Nonspiked samples decreased in DDT content (P < 0.01) on steritort processing and broiling. Spiked samples, however, lost DDT on steritorting (P < 0.05) but not during broiling. Total residues (DDE + DDD + DDT) also differed between spiked and nonspiked samples. Results indicated that research with pesticide residues should be conducted on naturally contaminated rather than artificially spiked matrices.
 
Article
Liver, intestinal mucosa, cloacal bladder, and kidney tissue were removed from five turtle species and assayed for adenosine triphosphatase (ATPase) activity following treatment with various concentrations of DDT for 30 min. These data indicate that the total (Na+,K+,Mg2+)-Mg2+-, and (Na+,K+)-dependent ATPases in the tissues of the five turtle species studied were significantly inhibited by 53 μM DDT. Treatment with 5.3 μM DDT caused some inhibition and stimulation. These results suggest that active transport may be severely affected by the action of DDT upon these ATPase systems.
 
Article
Crossbred yearling ewes were fed ad libitum for 10 or 16 weeks a control diet or a pelleted ration containing 250 ppm of technical 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) or 250, 1000, or 2500 ppm of technical methoxychlor (MeOCl). There were no differences in food consumption, body weight, liver weight, or uterine weight, water and glycogen. Examination of ovaries indicated that all animals were cycling. All treatments significantly increased liver microsomal enzyme activity. Although MeOCl was fed at 10× the DDT level, liver enzyme activity was less than with DDT. Demethylase activity was 5× control in DDT-treated sheep and 2-3× control in MeOCl-treated sheep. Hydroxylase activity was 2× control in DDT-treated sheep and 1.5× control in MeOCl-treated sheep.
 
Article
DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) is the major product from the anaerobic degradation of 1,1,1,2-tetrachloro-2,2-bis(p-chlorophenyl)ethane (DTE). This is the same reaction that is observed with electrochemical reduction, It is postulated that electrochemistry may be used as a means of predicting the products formed from the anaerobic reduction of organochlorine compounds.
 
Article
1,1,6-Trimethyl-1,2-dihydronaphthalene (TDN) is well-known to contribute "petrol" aromas to aged Riesling wines, but its prevalence and contribution to young Riesling or non-Riesling wines is not well understood. TDN concentrations were measured in 1-3-year-old varietal wines produced from Cabernet franc (n = 14 wines), Chardonnay (17), Cabernet Sauvignon (4), Gewurztraminer (4), Merlot (9), Pinot gris (6), Pinot noir (9), Riesling (28), or Sauvignon blanc (6). TDN concentrations in the Riesling wines, 6.4 ± 3.8 μg/L, were significantly higher than in all other varietals, 1.3 ± 0.8 μg/L. The odor detection thresholds for TDN were then determined in both model wine and a neutral white wine. Group sensory thresholds were found to be the same in both matrices, 2 μg/L, indicating little masking of TDN due to the odorants in the neutral white. The TDN sensory threshold was a factor of 10 below the previously reported odor threshold. On the basis of this revised threshold, 27 of 28 Riesling wines had suprathreshold TDN, whereas only 7 of 69 non-Riesling wines had suprathreshold TDN. The monoterpenes linalool and geraniol were also measured in the Riesling wines, and odor activity values (OAVs) were calculated for the monoterpenes and TDN. The OAV for TDN was higher than for the monoterpenes in 25 of 28 Riesling wines.
 
Article
A procedure has been developed for the determination of iron(III) dimethyldithiocarbamate by converting it into the iron(II)-bathophenanthroline complex, which is then dissolved in acetone-water (1:1), and the absorbance is measured at 534 nm against a reagent blank. Beer's law is obeyed over the concentration range 0.5-20 microg x mL(-1) in the final solution. The method is sensitive and highly selective and is used for the direct determination of ferbam in a commercial sample and in mixtures with various dithiocarbamates (ziram, zineb, maneb, etc.) and from wheat grains.
 
Article
A series of novel 12-(aryloxyacyloxyimino)-1,15-pentadecanlactone derivatives (3) were synthesized, and their structures including configuration of C=N bond were confirmed by (1)H NMR, elemental analysis and X-ray diffraction analysis. The bioassay showed that some of them exhibited excellent herbicidal activity against Amaranthus tricolor L. The activity of compounds 3 except compounds 3A1-2 was much higher than the commercial herbicide 2,4-D and the activity of about half of compounds 3 was comparable to the commercial herbicide tribenuron-methyl. The further bioassay showed that the representative of compounds 3, 3A1-12, exhibited excellent herbicidal activity not only against dicotyledon, such as Amaranthus tricolor L., Cucumis sativus L., Glycine max L., and Phaseolus radiatus L., but also against monocotyledon, such as Zea mays L. and Oryza sativa L.
 
Article
Fatty acid esters of 3-(N-phenylamino)-1,2-propanediol are currently considered the best chemical markers of toxic oils related to the Spanish toxic oil syndrome. Recent research in this area has undertaken the exhaustive and quantitative characterization of these compounds in oils collected during the epidemic outbreak. Current methods developed in this laboratory are based on solid phase extraction (SPE) using SCX cartridges followed by HPLC-APCI/MS/MS quantification. To circumvent the long and tedious extraction procedure, the SPE protocol was adapted for automatic extraction and the problems derived from the use of the immiscible solvents required for the SCX extraction were solved. Linearity of the analytical method was found in the same range as for the manual method. Extraction recoveries were 87 and 75% for 2-hydroxy-3-(N-phenylamino)propyl linoleate and 2-(linoleyloxy)-3-(N-phenylamino)propyl linoleate, respectively, and the corresponding coefficients of variation were approximately 1%, greatly improving reproducibility over manual procedures.
 
Article
1,2-Dicarbonyl compounds, formed from carbohydrates during thermal processing in the course of caramelization and Maillard reactions, are intensively discussed as precursors for advanced glycation endproducts in foods and in vivo. To obtain information about the uptake of individual compounds with commonly consumed foods, a comprehensive analysis of the content of 3-deoxyglucosone (3-DG), 3-deoxygalactosone (3-DGal), and methylglyoxal (MGO) together with 5-hydroxymethylfurfural (HMF) in 173 food items like bakery products, pasta, nonalcoholic and alcoholic beverages, sweet spreads, and condiments was performed. Following suitable cleanup procedures, 1,2-dicarbonyl compounds were quantitated after derivatization with o-phenylenediamine via RP-HPLC with UV detection. 3-DG proved to be the predominant 1,2-dicarbonyl compound with concentrations up to 410 mg/L in fruit juices, 2622 mg/L in balsamic vinegars, and 385 mg/kg in cookies, thus exceeding the corresponding concentrations of HMF. 3-DGal was found to be of relevance in many foods even in the absence of galactose. MGO was only of minor quantitative importance in all foods studied, except for manuka honey. Dietary intake was estimated to range between 20 and 160 mg/day for 3-DG and 5 and 20 mg/day for MGO, respectively.
 
Article
Although the importance of alpha-dicarbonyl compounds as reactive intermediates in the Maillard reaction and as precursors of heterocyclic and odor-active compounds is well-established, however, the detailed origin of many alpha-dicarbonyl compounds such as 3,4-hexanedione and 1,2-butanedione still remains unknown. Using glucose and glyoxal with labeled [(13)C-1]alanine, [(13)C-2]alanine, [(13)C-3]alanine, and [(15)N]alanine, the mechanism of their formation was investigated using the label incorporation pattern of the pyrazines derived through the Strecker reaction. Taking into account the non-oxidative mechanism of pyrazine formation, the data indicated that all of the ethyl-substituted pyrazines identified in the glyoxal/alanine model system incorporated C-2' and C-3' atoms of alanine, and not that of free acetaldehyde, as the ethyl group carbon atoms. This was achieved through spiking experiments using unlabeled acetaldehyde in the presence of labeled alanine. Furthermore, the data also indicated the occurrence of a chain elongation process of sugar-derived alpha-dicarbonyl compounds assisted by alanine. On the basis of the proposed mechanism, the glyoxal interaction with alanine through a decarboxylative aldol addition reaction can lead to the formation of 1,2-butanedione with the terminal ethyl carbon atoms originating from C-2' and C-3' atoms of alanine, and the similar interaction of 1,2-butanedione with a second molecule of alanine can lead to the formation of 3,4-hexanedione with both terminal ethyl carbon atoms originating from C-2' and C-3' atoms of alanine.
 
Article
1,2,3,4-Tetrahydro-beta-carboline-3-carboxylic acid (THCA) and 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCA), as two diastereoisomers (1S,3S and 1R,3S), occurred in commercial fruits. Citrus fruits exhibited the highest content; other fruits contained very low levels or none at all. The content of MTCA was as follows: orange, 0.35-2.47 microg/g; lemon, 0.15-2.05 microg/g; grapefruit, 1.12-8.37 microg/g; mandarin, 0.57-2.5 microg/g; banana, nd-0.74 microg/g; pear, nd-0.017 microg/g; grape, 0.01-0.22 microg/g, tomato, 0.05-0.25 microg/g; and apple, nd-0.012 microg/g). THCA, if present, usually occurred at <0.05 microg/g. Fruit ripening and softening during storage were accompanied with a significant increase of MTCA, in both pears and bananas. Those and previous results confirm that foods are an important source of tetrahydro-beta-carbolines in humans.
 
Article
A novel approach of periodate oxidation coupling with high performance liquid chromatography (HPLC)-fluorescence detector (FLD) for the quantitative determination of 3-chloro-1, 2-propanediol (3-MCPD) has been established. The essence of this approach lies in the production of chloroacetaldehyde by the oxidization cleavage of 3-MCPD with sodium periodate and the HPLC analysis of chloroacetaldehyde monitored by FLD detector after fluorescence derivatization with adenine. The experimental parameters relating to the efficiency of derivative reaction such as concentration of adenine, chloroacetaldehyde reaction temperature and time were studied. Under the optimized conditions, the proposed method can provide high sensitivity, good linearity (r2=0.999) and repeatability (relative standard deviations % between 2.57 and 3.44%), the limits of detection (LOD) and quantification (LOQ) were 0.36 ng/mL and 1.20 ng/mL respectively, and the recoveries obtained for water samples were in the range of 93.39 to 97.39%. This method has been successfully applied to the analysis of real water samples. Also this method has been successfully used for the analysis of vegetable oil samples after pretreatment with liquid-liquid extraction (LLE), the recoveries obtained by spiking experiment with soybean oil ranged from 96.27 to 102.42%. In comparison with gas chromatography (GC) or gas chromatography- mass spectrum (GC-MS), the proposed method can provide the advantages of simple instrumental requirement, easy operation, low cost and high efficiency, thus will make this approach to be another good choice for the sensitive determination of 3-MCPD.
 
Article
A series of hexahydroimidazo[1,2-a]pyridine derivatives were designed and synthesized through aza-Diels-Alder reactions and evaluated for insecticidal activities. Compounds 6a-d with endo-conformation were endowed with excellent insecticidal activities against cowpea aphid ( Aphis craccivora ) and armyworm ( Pseudaletia separata Walker), whereas exo-compounds 7a-d showed only low activities against cowpea aphid. The difference in activities between the endo- and exo-conformations indicated that conformation was the determinant of life or death of the insects for these compounds.
 
Top-cited authors
David Julian Mcclements
  • University of Massachusetts Amherst
Francisco A Tomás-Barberán
  • Spanish National Research Council
Chi-Tang Ho
  • Rutgers, The State University of New Jersey
Thomas Hofmann
  • Technische Universität München
Eric A Decker
  • University of Massachusetts Amherst