Search results for "ascorbic acid"
showing 10 items of 295 documents
**Arabidopsis thaliana** sequence analysis confirms the presence of cyt b-561 in plants: evidence for a novel protein family
2000
Recent advances in the Arabidopsis sequencing project has elucidated the presence of two genes Atb561-A and Atb561-B that show limited homology to the DNA sequence encoding for the mammalian chromaffin granule cytochrome b-561 (cyt b-561). Detailed analysis of the structural features and conserved residues reveals, however, that the structural homology between the presumptive Arabidopsis proteins and the animal proteins is very high. All proteins are hydrophobic and show highly conserved transmembrane helices. The presumably heme-binding histidine residues in the plant and animal sequences as well as the suggested binding site for the electron acceptor, monodehydroascorbate, are strictly co…
8-HYDROXY-2'DEOXYGUANOSINE LEVELS AND ANTIOXIDANT STATUS IN RAT LIVER FED WITH OLIVE AND CORN OIL DIETS: EFFECT OF ASCORBIC ACID SUPPLEMENATION
2001
DNA damage and antioxidants status were determined in liver of rat fed with olive and corn oil diets with and without ascorbic acid supplementation. In order to elucidate the role of fat intake, the study included a control and hyperlipidic diet. Liver antioxidant activities were significantly influenced by dietary fat and intake levels. In general, control groups fed with corn oil diets exhibited reduced liver antioxidant (SOD, catalase, and GSH-PX) and GSH levels compared with rats fed on olive oil diets. These activities were lower in rats consuming hyperlipidic diets relative to the control groups. Ascorbic acid supplementation resulted in a slight decrease of antioxidant activities bot…
High pressure processing of fruit juice mixture sweetened with Stevia rebaudiana Bertoni: Optimal retention of physical and nutritional quality
2013
Abstract The impact of high pressure processing (HPP) technology on physicochemical properties (color, browning index, turbidity index), bioactive compounds (ascorbic acid, total phenolic compounds, total anthocyanins, total carotenoids) and antioxidant capacity of a fruit juice mixture (papaya (32.5%, v/v), mango (10%, v/v) and orange (7.5%, v/v)) sweetened with Stevia rebaudiana Bertoni at different percentages was studied. The experimental design comprised a response surface methodology according to a central composite face-centered design. The variable ranges were 300–500 MPa (pressure), 5–15 min (time), 0–2.5% Stevia percentage. This design was used to determine the optimal high pressu…
Bioactive Components from Leaf Vegetable Products
2014
Abstract Traditionally, plant-based products have been used for different purposes. From ancient times, people on all continents have long applied poultices and imbibed infusions of indigenous plants. Numerous reports regarding the use of leaf vegetable products for the treatment of many human diseases have been made. Proven medicinal properties include antioxidant, anti-inflammatory, antiallergic, antibacterial, and antiviral effects. Most of these properties can be attributed to its high content in bioactive compounds. Bioactive compounds are secondary metabolites of plants, which are extra nutritional constituents that typically occur in small quantities in foods. They are being intensiv…
Water-soluble polysaccharides from Opuntia stricta Haw. fruit peels: Recovery, identification and evaluation of their antioxidant activities
2015
Abstract Opuntia stricta Haw. is considered as one of the most common cactus plant growing in Tunisia. Extracting valuable compounds from its fruit peel, considered as by-product, is drawing more and more attention, making it on the verge of commercialization. Water-soluble polysaccharides were extracted from Opuntia stricta Haw. peels, and their chemical composition assessed using thin layer chromatography. The antioxidant activities of the extracted polysaccharides were assessed using 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, total antioxidant activity and reducing power capacity. The extraction yield of water-soluble polysaccharides was 7.53±0.86%. The chemical comp…
Mathematic predictive models for calculating copper, iron and zinc dialysability in infant formulas
2001
Differences in the dialysability of a mineral element from infant formulas of the same type were detected in a previous study. As these may be due to the effects that different levels of the components of the formulas could have on dialysability, we attempted to establish mathematical models to predict the dialysability of Cu, Fe and Zn from infant formulas according to their ascorbic, citric, or selected amino acid contents. A simple linear regression was applied between the ascorbic acid, citric acid and amino acid contents and the Cu, Fe and Zn dialysability of 18 powdered infant formulas of different types. Significant correlations (P<0.05) were obtained between the dialysability of Fe …
Effects of ultrasound-assisted extraction on physicochemical properties, bioactive compounds, and antioxidant capacity for the valorization of hybrid…
2021
Samples of tree hybrid mandarins (´Clemenvilla`, ´Ortanique` and ´Nadorcott`) were employed to determine the physicochemical properties (increase of conductivity, brix° and pH), bioactive compounds (total phenolic, flavonoid, ascorbic acid and carotenoids content) and antioxidant capacity (DPPH and TEAC) of peels. Mandarin peel extracts were prepared employing ultrasound assisted extraction (400 W, 80% v/v duty cycle, 40ºC). The results were compared to the values of control extraction method. Aqueous ethanol solution (50%, v/v) was used as solvent in solid-liquid ratio of 1:10 (w/v). A 5, 15 and 30 min were applied in both methods to stablish the most effective extraction time. The increas…
Separation studies of amino acids, proteins and enzymes on bonded 1,2-dihydroxy-, 1,2-hydroxylamino-and amino silica packings
1979
1,2-dihydroxy-3-propoxypropyl (HPPS), 1-amino-2-hydroxy-3-propoxypropyl (AHPS) and 1-aminoethyl-3-aminopropyl (AEAPS) silica were synthesized by means of both a surface modification procedure (I) and a bulk modification procedure (II). Method (I) gave a surface concentration, α, of functional groups of 2–3 μmole/m2, whereas method (II) gave values up to 5 μmole/m2. Retention times, peak asymmetries and plate heights of thiamine and ascorbic acid eluted with aqueous buffer solutions ranging from pH 5.3 to 9.2 gave only a±5% variation over periods of 12 hours and more. The recoveries of selected enzymes and proteines examined under static and dynamic conditions were between 60% and 100% depen…
Stability of ascorbic acid in adapted milk-based infant formulae during storage
2004
A study was made of the effects of storage (for up to 17 months at 22 or 37 °C) on the ascorbic acid contents of four adapted milk-based infant formulae with the same composition except for the iron salt added (lactate or sulphate) and/or the vitamin E source involved (α-tocopherol (α-T) or α-tocopherol acetate (α-TAc)). Ascorbic acid was measured by a voltammetric method. The ascorbic acid contents of the formulae ranged from 0.77–0.84 g kg−1 immediately after manufacture to 0.41–0.48 g kg−1 after 17 months of storage. Samples stored at 22 °C had higher ascorbic acid contents than those stored at 37 °C. A multiple regression analysis performed to evaluate ascorbic acid evolution throughout…
Synthesis, crystallographic and spectroscopic characterization and magnetic properties of dimer and monomer ternary copper(II) complexes with sulfona…
2010
Abstract Three dinuclear and one mononuclear copper(II)-1,10-phenanthroline ternary complexes, [Cu(L1)(phen)(OH)]2 (1), [Cu(L2)(phen)(OH)]2·3H2O (2), [Cu(L3)(phen)(OH)]2 (3) and [Cu(L4)2(phen)(H2O)] (4), with thiadiazole sulfonamide derivative ligands: HL1 (N-(5-ethyl-1,3,4-thiadiazol-2-yl)naphthalene-1-sulfonamide), HL2 (N-(5-ethylthio)-1,3,4-thiadiazol-2-yl)-4-methylbenzenesulfonamide), HL3 (N-(5-ethyl-1,3,4-thiadiazol-2-yl)benzenesulfonamide) and HL4 (N-(5-ethyl-1,3,4-thiadiazol-2-yl)-4-methylbenzenesulfonamide) have been synthesized and characterized. In the four complexes each copper atom is five-coordinated. The structure of complexes 1, 2 and 3 consists of a dimeric unit with a C2 sy…