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41.
Study of the interaction of pancreatic lipase with procyanidins by optical and enzymatic methods 总被引：1，自引：0，他引：1
Gonçalves R Mateus N de Freitas V 《Journal of agricultural and food chemistry》2010,58(22):11901-11906
The interactions between porcine pancreatic lipase (PL) and grape seed procyanidins were studied by an enzymatic assay, fluorescence quenching, nephelometry, and dynamic light scattering (DLS). An inhibitory effect of grape seed procyanidins on lipase hydrolytic activity was found. Both the inhibition of lipase activity by procyanidins and the respective quenching of intrinsic protein fluorescence increased with the average degree of polymerization of the tested procyanidins. The association between procyanidins and enzyme involves a specific interaction as inferred from the fluorescence assays despite not changing significantly the tertiary structure of the protein. For all tested procyanidins it was shown, both by DLS and by nephelometry, that an increase in aggregation occurs up to a stoichiometric maximum after which further procyanidin addition causes a decrease in aggregation of aggregates. The maximum size of aggregates was shown to be closely related to the maximum overall aggregation. It was also shown that the inhibition of enzyme activity is to a large extent independent of the formation of aggregates. 相似文献
42.
Sousa C Mateus N Perez-Alonso J Santos-Buelga C Freitas Vd 《Journal of agricultural and food chemistry》2005,53(23):9249-9256
Several structurally related pigments were found to result from the reaction between catechin and coniferaldehyde/sinapaldehyde extracted from oak wood. Their structures were tentatively identified by mass spectrometry, and their formation was studied in different pH and temperature conditions for several days. They were all found to have a characteristic catechinpyrylium core, thereby constituting a new class of compounds named as oaklins. One of the main oaklins was also detected in a commercial table red wine aged in oak barrels. 相似文献
43.
Pedro Cardoso Israel Silva Nuno G. de Oliveira Artur R. M. Serrano 《Biological conservation》2004,120(4):517-524
A considerable number of alternative approaches have been suggested during the last years to predict species richness of a given taxon, while retaining information on the identities of the observed individuals. Such information can be extremely useful for choosing conservation priority areas, either by using raw richness values or, preferentially, by considering the complementarity between potential sites. Among the most popular approaches is the use of indicator taxa. Both one single family and a group of several families are here tested in their ability to predict the number of spider (Araneae) species independently of sampling effort, geographical location and type of habitat. We use data from three Portuguese protected areas as a test case. A two-family indicator group – Gnaphosidae and Theridiidae – is found to be a good surrogate of species richness, even if caution is needed regarding the comparison of sites with considerably different sampling effort or vegetation cover. No single family can be seen as a good surrogate of the totality of spiders. In addition, only a group of the two mentioned families is found to be efficient and reliable either when used to rank sites according to taxa richness or for determining near-minimum sets of sites for conservation. We therefore recommend surrogacy with this indicator group as a promising approach for the prediction of spider species richness or evaluation and ranking of areas according to their conservation importance. The reached conclusions should uphold for Portugal and the entire Mediterranean region. 相似文献
44.
Mateus N Silva AM Rivas-Gonzalo JC Santos-Buelga C de Freitas V 《Journal of agricultural and food chemistry》2003,51(7):1919-1923
Two newly formed anthocyanin-derived pigments that revealed unique spectroscopic features, showing maximum absorption in their UV-vis spectra at 575 nm, were isolated by TSK Toyopearl HW-40 (S) gel column chromatography and semipreparative HPLC from an aged Port red wine. Further characterization by ESI/MS and NMR ((1)H, gCOSY) showed them to belong to a new class of pigments described here for the first time, the structure of which consisted of a pyranoanthocyanin moiety linked to a flavanol by a vinyl bridge. The extended conjugation of the pi electrons throughout all the pigment molecule is likely to confer a higher stability on it and is probably the origin of the intense blue color. The formation of these pigments was found to arise from the reaction between anthocyanin-pyruvic acid adducts and vinyl-flavanol adducts. 相似文献
45.
Faria A Oliveira J Neves P Gameiro P Santos-Buelga C de Freitas V Mateus N 《Journal of agricultural and food chemistry》2005,53(17):6896-6902
A blueberry extract (A) and two anthocyanin-derived extracts (B and C) were prepared. The contents of polyphenols, flavonoids, anthocyanins, and anthocyanin-derived pigments of the extracts were determined for the first time. The pigment profile of blueberry extract A corresponded to 15 anthocyanins, whereas extract B was mainly composed of anthocyanin-pyruvic acid adducts of the blueberry original anthocyanins and extract C was mainly composed of the respective vinylpyranoanthocyanin-catechins (portisins). The extracts' abilities to inhibit lipid peroxidation, induced by 2,2'-azobis(2-methyl-propanimidamide) dihydrochloride in a liposomal membrane system were examined. The antioxidant capacities of the extracts were evaluated through monitoring oxygen consumption and by measuring the formation of conjugated dienes. All of the extracts provided protection of membranes against peroxyl radicals by increasing the induction time of oxidation. This effect increased with the polyphenol content and with the structural complexity of the anthocyanin-derived pigments of the extracts. The pigments present in extract C seemed to induce a higher protection of the liposome membranes toward oxidation. In addition, the antiradical properties and the reducing power of the extracts were determined by using DPPH and FRAP methods, respectively. The results from these assays were in agreement with those obtained with the liposome membranes. 相似文献
46.
47.
Sun B Neves AC Fernandes TA Fernandes AL Mateus N De Freitas V Leandro C Spranger MI 《Journal of agricultural and food chemistry》2011,59(12):6550-6557
The objective of this work was to study the evolution of the phenolic composition of red wine during vinification and storage and its relationship with some sensory properties (astringency and bitterness) and antioxidant activities. Thus, red wine was made by a classic vinification method with Castela?o and Tinta Miu?da grapes (Vitis vinifera L.) harvested at maturity (3:2; w/w). Samples were taken at 2 and 7 days of maceration, at second racking, at the time of bottling and at 6 and 14 months after bottling. The total polyphenols extract (TPx) in each sample was isolated by column chromatography. The phenolic composition (anthocyanins and proanthocyanidins), in vitro antioxidant activity, and sensory property (astringency, bitterness) of the isolated TPx from different winemaking stages were evaluated through high-performance liquid chromatography-diode array detection, 1,1-diphenyl-2-picrylhidrazyl radical test, ferric reducing antioxidant power assay, total phenolic index, MWI (polyphenol molecular weight index), TSA (tannin specific activity), and sensory panel tasting. The results showed that the phenolic composition of red wine varied significantly during winemaking. The intensity of astringency (IA) and the intensity bitterness (IB) of the isolated TPx from different winemaking stages increased from 2 days of maceration until second racking and then decreased. Furthermore, MWI and TSA are positively correlated with IA and IB. The in vitro antioxidant activity of the isolated TPx from different winemaking stages maintained unchanged after alcoholic fermentation, which was independent of the variation of phenolic composition and sensory properties. 相似文献
48.
Pirker KF Oliveira J de Freitas V Goodman BA Mateus N 《Journal of agricultural and food chemistry》2011,59(21):11833-11837
The free radical chemistry of two polyphenolic pigments from red wine, belonging to the family of portisins, has been investigated after reaction with O(2)(?-) radicals using electron paramagnetic resonance (EPR) spectroscopy. Two portisins derived from malvidin-3-glucoside and cyanidin-3-glucoside were used for this study. Stable free radicals were detected with both portisins and correspond to unpaired electrons localized on the B as well as F rings of the portisins. Interpretations were confirmed by comparison with the spectra of free radicals formed by oxidation of the model compounds cyanidin-3-glucoside, malvidin-3-glucoside, and catechin. These results concur with previous work reporting the higher antiradical properties of these pigments compared to their anthocyanin precursors. 相似文献
49.
Margarida Arrobas Nuno Conceição Ermelinda Pereira Sandra Martins Soraia Raimundo Cátia Brito Carlos Manuel Correia Manuel Ângelo Rodrigues 《Soil Use and Management》2023,39(4):1437-1452
In acid soils, when no-tillage farmers intend to apply lime, the question arises as to whether it should be incorporated into the soil or whether it can be left on the soil surface. In this study, two types of limestone, calcitic (Lcal) and dolomitic (Lmag), were tested in two olive groves of cv. Cobrançosa, with an initial pH of 4.9 (S. Pedro) and 5.5 (Raparigas). In S. Pedro, limestone was incorporated into the soil (Lburied) and in Raparigas, it was left on the floor (Lfloor). The use of limestone significantly increased soil pH in the 0–0.10 m layer in both experiments. In the 0.10–0.20 m soil layer, only Lmag increased significantly the soil pH in comparison with the control. Lmag was more effective than Lcal in increasing cation exchange capacity (CEC) and reducing exchangeable acidity (EA) and aluminium (Al3+) in the Lfloor experiment. Both limes increased leaf calcium (Ca) concentration, and Lmag increased the leaf levels of magnesium (Mg). In Lfloor experiment (higher soil pH), soil microbial carbon (C) decreased, and microbial nitrogen (N) increased with liming, which may indicate an increase in bacteria in the soil and a decrease in fungi. In Lburied experiment (initial pH of 4.9), liming significantly increased accumulated (2018–2021) olive yield (56 and more than 67 kg tree−1, respectively, in the control and liming treatments). In Lfloor experiment (initial pH of 5.5), the accumulated olive yields did not differ significantly between treatments (average values between 105 and 115 kg tree−1). The results of this study provide evidence that liming may increase olive yield in very acid soils and that dolomitic limestone should preferably be used by no-tillage farmers, due its higher solubility and faster effect on soil and trees. 相似文献
50.
Guilherme Helder O. Santos Fabio A. C. Costa Leandro S. Prado Verônica G. L. Palheta Glauber D. A. de Melo Nuno F. A. C. Luz Ronald K. Ribeiro Paula A. P. 《Aquaculture International》2022,30(1):323-339
This work evaluated the effects of food frequencies and self-feeding on the behavior, performance, and blood biochemistry of Colossoma macropomum. Juveniles weighing 3.63?±?0.05 g were distributed in 27 aquariums (40 L), with six fish per aquarium, to evaluate nine treatments in three replications in a 12L:12D photoperiod. The treatments were 24-h self-feeding (SF); daytime self-feeding at will (SFD); nighttime self-feeding at will (SFN); and feeding at fixed frequencies of two (2D), four (4D), and six times (6D) daytime and twice (2 N), four (4 N), and six times (6 N) nightly. The treatments were offered in automatic feeders, with fixed frequencies programmed. Extruded commercial feed, with 46% protein, was used. The experimental period was 40 days. In the SF treatment, the animals exhibited 95.7% nocturnal and 4.3% diurnal feeding activity (p?<?0.05). In the treatment SFD and SFN, the animals showed feeding activity throughout the day and night. Final weight, weight gain, and total feed intake were higher for animals at fixed daytime and nighttime frequencies (p?<?0.05). Feed conversion was better for animals in SF, SFD, 4D, SFN, and 4 N (0.89, 0.76, 0.91, 0.85, and 0.88, respectively) (p?<?0.05). Cholesterol and high-density lipoproteins were lower for fish in SF, SFN, 2 N, 4 N, and 6 N (p?<?0.05). SF treatment animals had lower triglyceride content, 154.20 mg dL?1 (p?<?0.05). Colossoma macropomum has nocturnal food preferences, however, with remarkable plasticity. Juveniles of this species fed four times during the day or night show good performance. Dietary patterns influenced the blood metabolic indicators of this species and the periods studied.
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