Home About us Contact
|
Home About us Contact | ||
|
|
||
Food Extracts (food + extract)
Selected AbstractsANALYSIS OF ANTIOXIDANT POTENTIAL USING A BIOASSAY BASED ON OXIDATION OF 5-(2 AMINOETHYL)BENZENE-1,2,4-TRIOL FOR SCREENING PLANT FOOD EXTRACTSJOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2007YU YAO ABSTRACT Neurotoxic products including reactive quinones and oxygen species such as H2O2 are generated upon oxidation of 4-(2-aminoethyl)-1,2-benzenediol (dopamine) and 5-(2-aminoethyl)benzene-1,2,4-triol (6-OH dopamine). Moreover, neurotoxicity of 6-OH dopamine and related oxidative stress may be increased in the presence of cytochrome c (Cytc) that is released from its normal mitochondrial location. A Cytc-enhanced 6-OH dopamine oxidation reaction is presented as a model bioassay for identifying possible neuroprotective food antioxidants and their metabolites. A concentration-dependent effect was observed for Cytc upon 6-OH dopamine oxidation. Fruit/vegetable extracts, prepared from Fragaria and Pisum, were tested by this assay; a three- to fourfold greater antioxidant potency was observed for Fragaria. The results were discussed in terms of the content for antioxidant phytochemicals. In addition, potencies for these dietary antioxidants were compared to those of a related assay based on N,N,N,,N,-tetramethyl-1,4-phenylene-diamine peroxidation. PRACTICAL APPLICATIONS The bioassay presented herein is intended to be used for screening the antioxidant activities of purified dietary compounds and their in vivo metabolites, as well as crude plant extracts and other food preparations. Examples are provided by the use of fruit and vegetable extracts; and these activities arecompared with those of purified phytochemicals. Because of the potential relevance of this assay to some neurological disorders and mitochondrial dysfunctions, phytochemicals and food extracts with strong protective activities in this initial screen may be good candidates for further analyses (biochemical, cellular and animal experiments) related to such disorders e.g., related to dopaminergic neurodegeneration as discussed below. [source] Paddlefish Polyodon spathula juveniles food searching behaviour evoked by natural food odourJOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2007A. O. Kasumyan Summary Using the behavioural bioassay, food search behaviour was investigated in paddlefish Polyodon spathula juveniles (2.3, 3.0, 5.0, 15.0 and 35.0 cm TL; and 16, 23, 35, 50 and 130 days post-hatch respectively) evoked by Daphnia water extracts. Main characteristics of this behaviour were increased swimming speed, sinking to the lower water layer, short and straight trajectories in the odour cloud and opening of the mouth. These responses were seldom clearly pronounced and had a fairly short time-pattern. Biting and snapping, common in food search by many other species, were never observed. Ability to respond to food odour developed at the beginning of exogenous feeding. Olfactory sensitivity of P. spathula to natural food extract was relatively low, 10,1,10,2 g L,1, 2,3 orders of magnitude lower than in some sturgeons. It was concluded that olfaction plays a minor role in the food search behaviour of paddlefish. [source] ANALYSIS OF ANTIOXIDANT POTENTIAL USING A BIOASSAY BASED ON OXIDATION OF 5-(2 AMINOETHYL)BENZENE-1,2,4-TRIOL FOR SCREENING PLANT FOOD EXTRACTSJOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2007YU YAO ABSTRACT Neurotoxic products including reactive quinones and oxygen species such as H2O2 are generated upon oxidation of 4-(2-aminoethyl)-1,2-benzenediol (dopamine) and 5-(2-aminoethyl)benzene-1,2,4-triol (6-OH dopamine). Moreover, neurotoxicity of 6-OH dopamine and related oxidative stress may be increased in the presence of cytochrome c (Cytc) that is released from its normal mitochondrial location. A Cytc-enhanced 6-OH dopamine oxidation reaction is presented as a model bioassay for identifying possible neuroprotective food antioxidants and their metabolites. A concentration-dependent effect was observed for Cytc upon 6-OH dopamine oxidation. Fruit/vegetable extracts, prepared from Fragaria and Pisum, were tested by this assay; a three- to fourfold greater antioxidant potency was observed for Fragaria. The results were discussed in terms of the content for antioxidant phytochemicals. In addition, potencies for these dietary antioxidants were compared to those of a related assay based on N,N,N,,N,-tetramethyl-1,4-phenylene-diamine peroxidation. PRACTICAL APPLICATIONS The bioassay presented herein is intended to be used for screening the antioxidant activities of purified dietary compounds and their in vivo metabolites, as well as crude plant extracts and other food preparations. Examples are provided by the use of fruit and vegetable extracts; and these activities arecompared with those of purified phytochemicals. Because of the potential relevance of this assay to some neurological disorders and mitochondrial dysfunctions, phytochemicals and food extracts with strong protective activities in this initial screen may be good candidates for further analyses (biochemical, cellular and animal experiments) related to such disorders e.g., related to dopaminergic neurodegeneration as discussed below. [source] Single Laboratory Method Performance Evaluation for the Analysis of Total Food Folate by Trienzyme Extraction and Microplate AssayJOURNAL OF FOOD SCIENCE, Issue 5 2007L. Chen ABSTRACT:, Single laboratory method performance parameters, including the calibration curve, accuracy, recovery, precision, limit of detection (LOD), and limit of quantification (LOQ), were evaluated for the analysis of total food folate by the trienzyme extraction and microplate assay with Lactobacillus casei subsp. rhamnosus. Standard Reference Material (SRM) 1546 (meat homogenate), SRM 2383 (baby food composite), SRM 1846 (infant formula), Certified Reference Material (CRM) 121 (wholemeal flour), and CRM 485 (mixed vegetables), representing a broad selection of food matrices, were used to evaluate the performance of the method. A generated 4-parameter logistic equation of the calibration curve was y= (0.0705 , 1.0396)/(1 + (x/0.0165) 1.3072) + 1.0396 (P < 0.0001). The test of parallelism demonstrated that matrix components in the food extracts did not affect the accuracy. Measured values of the SRMs and CRMs were within their certified or reference values. Recoveries for all reference materials met the requirements of the AOAC guidelines for single laboratory validation. Precision measured as repeatability, including simultaneous and consecutive replicates for each SRM and CRM, met the Horwitz criterion. LOD and LOQ values were 0.3 and 0.6 ,g/100 g, respectively. The results showed that trienzyme digestion using ,-amylase, PronaseR, and conjugase from chicken pancreas coupled with a 96-well microplate assay provided a highly accurate, reproducible, and sensitive method for the determination of folate in a variety of foods. [source] Injector-internal thermal desorption from edible oils performed by programmed temperature vaporizing (PTV) injectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 15 2006Anja Fankhauser-Noti Abstract Injector-internal thermal desorption is a promising technique for the analysis of a wide range of food components (e. g., flavors) or food contaminants (e. g., solvent residues, pesticides, or migrants from packaging materials) in edible oils and fats or fatty food extracts. Separation from the fatty matrix occurs during injection. Using programmed temperature vaporizing (PTV) injection, the oily sample or sample extract was deposited on a small pack of glass wool from which the components of interest were evaporated and transferred into the column in splitless mode, leaving behind the bulk of the matrix. Towards the end of the analysis, the oil was removed by heating out the injector and backflushing the precolumn. The optimization dealt with the gas supply configuration enabling backflush, the injector temperature program (sample deposition, desorption, and heating out), separation of the sample liquid from the syringe needle and positioning it on a support, deactivation of the support surface, holding the plug of fused silica wool by a steel wire, and the analytical sequence maintaining adsorptivity at the desorption site low. It was performed for a mixture of poly(vinyl chloride) (PVC) plasticizers in oil or fatty food. Using MS in SIM, the detection limit was below 0.1 mg/kg for plasticizers forming single peaks and 1 mg/kg for mixtures like diisodecyl phthalate. For plasticizers, RSDs of the concentrations were below 10%; for the slip agents, oleamide and erucamide, it was 12%. The method of incorporating PTV injection was used for about one year for determining the migration from the gaskets of lids for glass jars into oily foods. [source] The temporal sequence of allergic sensitization and onset of infantile eczemaCLINICAL & EXPERIMENTAL ALLERGY, Issue 4 2007A. J. Lowe Summary Background Eczema is commonly associated with sensitization in infants, but the causative role of sensitization in the development of eczema has been questioned. Objective To determine if allergic sensitization increases the risk of developing eczema, or alternatively, if eczema increases the risk of developing allergic sensitization. Methods We used data from the Melbourne Atopy Cohort Study, a prospective birth cohort of 552 infants with a family history of atopic disease. The main outcomes were risk of developing eczema from 6 months to 7 years of age in asymptomatic infants; and risk of developing sensitization, as measured by skin prick tests to milk, egg white, peanut, house dust mite, rye grass pollen and cat extracts, in previously unsensitized infants. Results Sensitization to food extracts at 6 months was associated with an increased risk of developing eczema [hazard ratio (HR) 1.63, 95% confidence interval 1.13,2.35] up to 7 years of age, after excluding infants with eczema in the first 6 months. However, eczema in the first 6 months was also associated with increased risk of new sensitization at both 1 year (HR 2.34, 1.38,3.98) and 2 years (HR 3.47, 1.65,7.32). Conclusion In some infants, sensitization precedes and predicts the development of eczema, while in others eczema precedes and predicts the development of sensitization. This indicates that there are multiple pathways to atopic eczema. [source] | ||||||||||