Antioxidant activity of ethanolic extracts from several asparagus cultivars   总被引：3，自引：0，他引：3  

Rodríguez R  Jaramillo S  Rodríguez G  Espejo JA  Guillén R  Fernández-Bolaños J  Heredia A  Jiménez A 《Journal of agricultural and food chemistry》2005,53(13):5212-5217

Three different methods (antiradical activity, inhibition of primary oxidation, and ferric reducing power) have been used to evaluate the antioxidant activity of eight different asparagus cultivars and byproducts: white and green asparagus from Alcalá del Río (Guadalquivir Valley, Seville) and American hybrids, native spears, and their byproducts from Huétor-Tájar (Vega de Granada). The correlation between antioxidant activity and total phenol content was studied. Six standards were also tested to validate the modified methods for antioxidant activity determination. Results obtained for antiradical capacity and reducing power were very similar, and a high correlation with phenols was found (R > or = 0.9 for both tests). Sample origin was an important factor, spears from Huétor-Tájar having higher values (ARC between 7 and 10 and P(R) of 0.25-0.33) than those from Alcalá del Río (ARC 0.6-2 and P(R) of 0.05-0.07). Significant differences were found between spears with the same origin, suggesting that genetics are another factor to take into account. Asparagus inhibits lipid primary oxidation, but no correlation between the inhibition percentage and phenols was observed. Asparagus origin was the only factor that led to significant differences: samples from Huétor-Tájar had higher values (POIC between 18 and 32) than those from Alcalá del Río (POIC of 5-9). Byproducts from the canning industry at Huétor-Tájar were also assayed for antioxidant activity; the results obtained suggested that byproducts could be considered as an excellent source of natural antioxidants.  相似文献   

Effect of germination on the carbohydrate composition of the dietary fiber of peas (Pisum sativum L.)     

Martín-Cabrejas MA  Ariza N  Esteban R  Mollá E  Waldron K  López-Andréu FJ 《Journal of agricultural and food chemistry》2003,51(5):1254-1259

The effect of different conditions of pea germination on dietary fiber (DF) composition was studied. Insoluble dietary fiber (IDF) and soluble dietary fiber (SDF) were subjected to acid hydrolysis, and the resultant neutral sugars, uronic acids, and Klason lignin were quantified. Germinated peas exhibited significantly higher contents of total dietary fiber (TDF) than the raw sample, due to the increases of both DF fractions. Under darkness conditions, germination exhibited the highest contents of IDF and SDF. Decreasing IDF/SDF ratios showed that the carbohydrate changes did not take place to the same extent during germination, the SDF fraction being the most affected. The detailed chemical composition of fiber fractions reveals increases of cellulose in the IDF of germinated samples, whereas SDF exhibits a decrease of pectic polysaccharides and also increases of polysaccharides rich in glucose and mannose. The DF results were corroborated by a comparative examination of the cell wall carbohydrate composition.  相似文献   

Possible role of plant phenolics in the production of trichothecenes by Fusarium graminearum strains on different fractions of maize kernels     

Bakan B  Bily AC  Melcion D  Cahagnier B  Regnault-Roger C  Philogène BJ  Richard-Molard D 《Journal of agricultural and food chemistry》2003,51(9):2826-2831

Four trichothecene-producing strains of Fusarium graminearum were grown on three maize grain fractions, whole grain, degermed grain, and the germ, to determine the effect of natural substrates on mycotoxin production. Monitoring the ergosterol content after 25 days of incubation indicated that fungal growth on all grain fractions was comparable. Trichothecene (TCT) production was highest on degermed grain, less on whole grain, and very low or nondetectable on the germ; similar results were found with four different strains. It was concluded that inhibitor(s) of TCT biosynthesis were present in maize germ. The presence of phenolic compounds was investigated in the different fractions. The hydroxamate 4-acetylbenzoxazolin-2-one (4-ABOA), a known inhibitor of mycotoxin production, was found in the degermed and whole grain fractions but not in the germ. Therefore, the TCT inhibition observed on the maize germ fraction used in our study is clearly not linked to 4-ABOA. Other soluble phenolic compounds were found at a much higher concentration in the germ than in the two other fractions. The inhibition property of the soluble ester-bound extracts was tested in liquid culture. A possible role for these compounds is discussed.  相似文献   

Analysis of two bentonites of enological interest before and after commercial activation by solid Na(2)CO(3)     

Gougeon RD  Soulard M  Miehé-Brendlé J  Chézeau JM  Le Dred R  Jeandet P  Marchal R 《Journal of agricultural and food chemistry》2003,51(14):4096-4100

Two natural calcium-rich bentonites used for the removal of wine proteins, originating from Greece and Turkey, were studied by X-ray diffraction, thermal analysis, and solid state NMR, before and after activation by solid Na(2)CO(3). Exchange of Ca(2+) by Na(+) mainly occurs for cations located at the edge of layers and only weakly for interlayer cations. This Na(2)CO(3) activation process leads to an increased efficiency in the adsorption process of bovine serum albumin (BSA) used as a model protein for both bentonites. A direct correlation is observed between the extent of Ca(2+)/Na(+) exchange, the strength of adsorption of BSA, and the extent of unfolding of BSA backbone.  相似文献   

Pectins as possible source of the copper involved in the green staining alteration of cv. Gordal table olives     

Gallardo-Guerrero L  Hornero-Méndez D  Mínguez-Mosquera MI 《Journal of agricultural and food chemistry》2002,50(23):6746-6751

The pectic and pigment compositions and Ca and Cu contents of the alcohol-insoluble solid (AIS) residues were determined in cv. Gordal olives treated with NaOH solution and kept at different constant pH values (3.5-6.5). The same controls were made in table olives presenting green staining alteration. The ratio between the various pectin fractions of the more acid pH experiment samples remained similar in fruits not showing green staining. In altered fruits, the protopectin fraction was lower, and the calcium pectate or EDTA soluble pectins were higher. Regarding the presence of Ca and Cu in the AIS, it was observed that, whereas Ca levels fell at the most acid pH values, those of Cu increased. The concentration of Ca was higher in the AIS of altered olives than in nonaltered ones. The same trend was seen for the zone with or without green staining of an altered fruit. In the case of Cu, the relationship was the opposite: a decrease in the levels of AIS Cu in fruits and zones of fruits with green staining. This result was correlated with the highest concentration of Cu-chlorophyll complexes found in such samples and suggested that pectins might act as a reservoir of Cu involved in the alteration.  相似文献   

Study of carbendazin residue accumulation on greenhouse and field-grown strawberries, after successive treatments with benomyl     

A Mònico-Pifarré  M Xirau-Vayreda 《Journal of the Association of Official Analytical Chemists》1990,73(4):553-556

Benomyl, a systemic fungicide used in preharvest treatments to prevent Botrytis and other fungal diseases, metabolizes to carbendazim (MBC). A study was undertaken to determine if the total residues of MBC of greenhouse and field-grown Douglas strawberries accumulate in fruits after successive fortnightly treatments with a commercial preparation of benomyl. Statistical analysis of the data obtained indicates that residues of MBC do not accumulate in fruits; on the contrary, they decrease over time.  相似文献   

Limited downward migration of pollutant metals (Cu,Zn, Ni,and Pb) in acidic virgin peat soils near a smelter     

S. Dumontet  M. Lévesque  S. P. Mathur 《Water, air, and soil pollution》1990,49(3-4):329-342

The distribution of pollutant heavy metals (Cu, Zn, Ni, Cd, and Pb) was determined in 11 acidic virgin peat profiles located along two transects moving away from a smelter plant in the Noranda region of Quebec. The levels of all five metals were found highest in the 0 to 15 cm layer at site near the smelter, and decreased progressively with the distance from the smelter, up to 42 km. Copper had the highest concentrations (5525 μg g^?1) followed by Pb and Zn. The maximum levels of total metals built up in the peat surface near the smelter were high, approximately reaching the threshold limits for phytotoxicity in peat soils. The amounts of heavy metals moving down and accumulating in the anaerobic zone of the peat profiles were limited. The distribution and enrichment ratios in the profiles showed that Cu, Zn, and Cd would have relatively higher mobility than Pb.  相似文献   

Critical loads for nitrogen deposition on forest ecosystems   总被引：2，自引：0，他引：2  

E. - D. Schulze  W. De Vries  M. Hauhs  K. Rosén  L. Rasmussen  C. -O. Tamm  J. Nilsson 《Water, air, and soil pollution》1989,48(3-4):451-456

Critical loads for N deposition are derived from an ecosystem's anion and cation balance assuming that the processes determining ecosystem stability are soil acidification and nitrate leaching. Depending on the deposition of S, the parent soil material, and the site quality critical N deposition rates will range between 20 to 200 mmol m^?2 yr^?1 (3 to 14 kg ha^?1 yr^?1) on silicate soils and reach 20 to 390 mmol m^?2 yr^?1 (3 to 48 kg ha^?1) on calcareous soils.  相似文献   

Genetic Relationships and Variation among Biotypes of Dallisgrass (Paspalum dilatatum Poir.) and Related Species Using Random Amplified Polymorphic DNA Markers     

Rogéria Beatriz Miz  Tatiana Teixeira de Souza-Chies 《Genetic Resources and Crop Evolution》2006,53(3):541-552

The genus Paspalum L. consists of more than 400 species. Around twenty-five informal groups of species are recognized in Paspalum and the Dilatata group is of special interest because its members are excellent potential forage grasses. Seventy-five germplasm accessions, representing 15 taxa, were analyzed using randomly amplified polymorphic DNA (RAPD). Polymorphisms were observed with twenty-two primers in the Dilatata group and 16 of those were analyzed. Four hundred and four different RAPD fragments were generated, resulting in an average of 25.2 bands per primer. Among the 404 markers analyzed, 48 (11.88%) were exclusive for the P. dilatatum Poir. biotypes, 31 (7.67%) were exclusive to taxa belonging to other groups included in this study, 28 markers (6.93%) were diagnosed for other species of the Dilatata group and 16 (3.96%), for natural hybrids. Extensive RAPD variation was found among the species studied. Inter- and intra-taxonomic polymorphisms were detected. A dendrogram based on the RAPD data shows some clusters corresponding to the same taxa. However, the biotypes of P. dilatatum do not form a cluster. The present work confirms that the RAPD technique can be used to determine genetic relationships between the taxa belonging to the Dilatata group.  相似文献   

Differential transfer of organic micropollutants through intestinal barrier using Caco-2 cell line     

Cavret S  Feidt C  Laurent F 《Journal of agricultural and food chemistry》2005,53(7):2773-2777

Food seems to be one of the main ways of animal and human contamination with polycyclic aromatic hydrocarbons (PAHs) and dioxins. In vivo studies showed a blood absorption of these xenobiotics after their ingestion. Our work aimed at studying the in vitro transfer of PAHs and dioxins through intestinal barrier. Caco-2 cells were cultivated on permeable filters to measure transepithelial permeability of (14)C labeled 2,3,7,8-tetrachlorodibenzo-p-dioxin, benzo[a]pyrene, pyrene, and phenanthrene, which differed in their physicochemical properties. The results showed that the molecules were able to cross intestinal cell layers. All the molecules were detected associated with cells, even if the dioxin was the less uptaken compound. Phenanthrene appeared in basal media faster, and its level after a 6-h exposure was respectively 1.1, 2, and 7 times higher than pyrene, benzo[a]pyrene, and 2,3,7,8-tetrachlorodibenzo-p-dioxin levels. These findings suggest that intestinal epithelium plays a key role in selective permeability and then in bioavailibility of micropollutants.  相似文献