In vitro antioxidant activity of coffee compounds and their metabolites   总被引：2，自引：0，他引：2  

Gómez-Ruiz JA  Leake DS  Ames JM 《Journal of agricultural and food chemistry》2007,55(17):6962-6969

In this paper we report the antioxidant activity of different compounds which are present in coffee or are produced as a result of the metabolism of this beverage. In vitro methods such as the ABTS*+ [ABTS = 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] decolorization assay and the oxygen radical absorbance capacity assay (ORAC) were used to assess the capacity of coffee compounds to scavenge free radicals. The importance of caffeine metabolites and colonic metabolites in the overall antioxidant activity associated with coffee consumption is shown. Colonic metabolites such as m-coumaric acid and dihydroferulic acid showed high antioxidant activity. The ability of these compounds to protect human low-density lipoprotein (LDL) oxidation by copper and 2,2'-azobis(2-amidinopropane) dihydrochloride was also explored. 1-Methyluric acid was particularly effective at inhibiting LDL oxidative modification. Different experiments showed that this caffeine metabolite is not incorporated into LDL particles. However, at physiologically relevant concentrations, it was able to delay for more than 13 h LDL oxidation by copper.  相似文献   

Kinetic study of the activation of banana juice enzymatic browning by the addition of maltosyl-beta-cyclodextrin     

López-Nicolás JM  Pérez-López AJ  Carbonell-Barrachina A  García-Carmona F 《Journal of agricultural and food chemistry》2007,55(23):9655-9662

In recent years, the use of cyclodextrins (CDs) as antibrowning agents in fruit juices has received growning attention. However, there has been no detailed study of the behavior of these molecules as substances, which can lead to the darkening of foods. In this paper, when the color of fresh banana juice was evaluated in the presence of different CDs, the evolution of several color parameters was the opposite of that observed in other fruit juices. Moreover, a kinetic model based on the complexation by CDs of the natural browning inhibitors present in banana is developed for the first time to clarify the enzymatic browning activation of banana juice. Finally, the apparent complexation constant between the natural polyphenoloxidase inhibitors present in banana juice and maltosyl-beta-CD was calculated (Kci = 27.026 +/- 0.212 mM (-1)).  相似文献   

Proteomic identification of actin-derived oligopeptides in dry-cured ham     

Sentandreu MA  Armenteros M  Calvete JJ  Ouali A  Aristoy MC  Toldrá F 《Journal of agricultural and food chemistry》2007,55(9):3613-3619

An intense proteolysis of muscle proteins, mainly due to the action of endogenous proteolytic enzymes, has been reported to occur during the processing of dry-cured ham. This gives rise to an important generation of free amino acids and peptides of small size that contribute directly or indirectly to flavor characteristics of the final product. The nature and properties of the free amino acids generated during postmortem proteolysis have been well established. However, little is known about the identity of peptides generated during the processing of dry-cured ham. In the present paper, we describe the isolation (by ethanol precipitation followed by size exclusion and reverse phase chromatographies) and identification (by matrix-assisted laser desorption/ionization time-of-flight MS and collision-induced dissociation MS/MS) in a Spanish dry-cured ham of the following four oligopeptides: (A) TKQEYDEAGPSIVHR, (B) ITKQEYDEAGPSIVHRK, (C) DSGDGVTHNVPIYE, and (D) DSGDGVTHNVPIYEG. This is the first time that these peptide fragments have been reported in dry-cured ham at the end of processing. Sequence homology analysis revealed that the four peptides originated from muscle actin, indicating an extensive hydrolysis of this protein during dry-curing. Some of the cleavage sites corresponding to these fragments in actin were reproduced by other authors through the incubation of this myofibrillar protein in the presence of cathepsin D (EC 3.4.23.5), thus supporting a relevant action of this enzyme during the processing of dry-cured ham.  相似文献   

Effect of spinal cord transection on feather release in the slaughtered broiler     

I. M. Levinger  S. Angel 《British poultry science》1977,18(2):169-172

1. Transection at the level of the first cervical vertebra causes a marked loosening of feather‐skin connection, although less than that found in the living animal. This effect may be seen even when transection is carried out 2.lb5 min after bleeding.

2. Cuts performed in other levels had little or no effect.  相似文献   

Loosening of the feather follicle attachment by subcutaneous application of crude papain     

S. Angel  M. Hyams  I. M. Levinger 《British poultry science》1982,23(3):251-255

1. The application of crude papain to cause loosening of feathers in chickens after death was successful in a laboratory experiment.

2. The treatment disrupted keratin cross‐bridges between the feather shaft and the follicle, and may have proteolysed feather follicle muscles.  相似文献   

Enhancement of cation diffusion rates across the 410-kilometer discontinuity in Earth's mantle     

S Chakraborty  R Knoche  H Schulze  DC Rubie  D Dobson  NL Ross  RJ Angel 《Science (New York, N.Y.)》1999,283(5400):362-365

Rates of cation diffusion (magnesium, iron, and nickel) have been determined in olivine and its high-pressure polymorph, wadsleyite, at 9 to 15 gigapascals and 1100 degrees to 1400 degreesC for compositions that are relevant to Earth's mantle. Diffusion in olivine becomes strongly dependent on composition at high pressure. In wadsleyite, diffusion is one to two orders of magnitude faster than in olivine, depending on temperature. Homogenization of mantle heterogeneities (chemical mixing) and mineral transformations involving a magnesium-iron exchange will therefore occur considerably faster in the transition zone than at depths of less than 410 kilometers.  相似文献   

Dynamic stock model for analysing semi‐intensive production of whiteleg shrimp Litopenaeus (Penaeus) vannamei affected by the acute hepatopancreatic necrosis disease: Assessment of disease severity indicators and relationships with pond water quality parameters     

Nallely Estrada‐Perez  Javier M. J. Ruiz‐Velazco  Francisco J. Magallon‐Barajas  Angel I. Campa‐Cordova  Alfredo Hernndez‐Llamas 《Aquaculture Research》2020,51(1):242-254

The production of Litopenaeus vannamei was analysed when affected by the acute hepatopancreatic necrosis disease using a dynamic stock model and primary data of seven production cycles from a shrimp farm in Mexico from 2013 to 2016. Significant results (p < .05) of the correlation analysis indicated that during those years mortalities by the disease were more severe when water salinity was high and productivity was low. Significant results from ANOVA showed that throughout the period, disease severity and salinity diminished while pond productivity initially declined but subsequently improved. Significant results from regression analyses conducted for each production cycle also indicated the importance of salinity and productivity on disease severity and showed that early mortality by the disease occurred in ponds with warmer water. Within the observed range of water quality parameters, increases of 1 cm in water transparency and 1 g/L in salinity resulted in increments within 0.17%–0.25% and 1.7%–3.1% in shrimp mortality by the disease. When increases of 1°C in water temperature were recorded, outbreaks occurred 0.2–1.57 weeks earlier. In conclusion, the disease strongly determines the dynamics of shrimp production, and the role of salinity, productivity and temperature is worthy of further delving.  相似文献   

Use of a byproduct of magnesium oxide production to precipitate phosphorus and nitrogen as struvite from wastewater treatment liquors   总被引：3，自引：0，他引：3  

Quintana M  Colmenarejo MF  Barrera J  García G  García E  Bustos A 《Journal of agricultural and food chemistry》2004,52(2):294-299

This paper describes a series of experiments designed to recover phosphorus and nitrogen from sewage in the form of struvite (MgNH(4)PO(4).6H(2)O), a potential fertilizer. Nitrogen and phosphate were recovered from a filtrate of digested sludge dewatered at the Arroyo del Soto Waste Water Treatment Plant (WWTP) (Madrid, Spain). A byproduct of the Spanish magnesite mining and MgO production industry was used as the magnesium source. The precipitating performance of this byproduct was compared to that of conventional chemical reagents such as pure MgO. The precipitates obtained were subjected to chemical, light microscopy, and X-ray diffraction analysis. The findings indicate the precipitate recovered using this byproduct contains several minerals with a predominance of struvite. Optimal purity ( approximately 80% struvite) was achieved using the sieved <0.04 mm grain size fraction of the byproduct at doses corresponding to a molar Mg:P ratio of 1.6.  相似文献   

Management of paddlefish fry and juveniles in Bulgarian conditions     

Tania Hubenova  Angel Zaikov  Penka Vasileva 《Aquaculture International》2007,15(3-4):249-253

When paddlefish larvae were reared in tanks and fed on zooplankton, a length of 12–15 cm and a weight of 9.2 g had been obtained by the second month after hatching. After a further 2-months of pond rearing, the survival rate was 48%, and the juveniles had reached an average weight of 27.74 g and length of 22.5 cm. Much better growth rate was achieved when both paddlefish fry and juveniles were reared only on artificial food in tanks. At the end of the first month, a weight of 11.6 g had been reached; at the second month the paddlefish weight was 33.29 g, at the third month it was 60.2 g, and at the fourth month it was 127.7 g. There were two cases in which, respectively, 1,000 and 1,500 paddlefish with an average body weight of 33–60 g were stocked in a reservoir. At the age 5 months the fish had reached, or exceeded, an average weight of 500 g, and, after 1 year, it was over 700 g, which is an indicator of the good rearing opportunities this reservoir offered.  相似文献   

Bradycardia, altered thermographic patterns, and dysphonia associated with cervical laxity in an Ankole-Watusi bull     

J W Tyler  K L Angel  R L Carson  T Anderson  R C Purohit 《Journal of the American Veterinary Medical Association》1991,199(6):767-768

A native African bull was examined for ataxia of 10 days' duration. Clinical signs included bradycardia, ataxia, hypermetria, and dysphonia. Cerebrospinal creatine kinase activity was high. Thermographic evidence of bilateral accessory nerve dysfunction was observed. This finding was supported by electromyographic studies. Survey and positive contrast radiographs were nondiagnostic. Clinical signs exacerbated after radiographic examination. Treatment included dexamethasone and flunixin meglumine administered IV.  相似文献