Search results for "ascorbic acid"
showing 10 items of 295 documents
Determination of active ingredients in cough-cold preparations by micellar liquid chromatography.
2000
The chromatographic behaviour of some active ingredients in cough-cold pharmaceutical preparations, the antihistamine chlorpheniramine (or the dextro enantiomer dexchlorpheniramine), and the phenethylamines phenylephrine, phenylpropanolamine and pseudoephedrine, has been studied using a C(18) column, micellar mobile phases of sodium dodecyl sulphate (SDS) and pentanol, and with UV detection. All possible combinations of chlorpheniramine/phenethylamine were resolved and determined using a mobile phase of 0.15 M SDS-6% (v/v) pentanol at pH 7, with analysis time below 7 min. Repeatabilities and within laboratory precisions were evaluated at four different drug concentrations in the range 0.5-2…
Highly selective detection of Epinephrine at oxidized Single-Wall Carbon Nanohorns modified Screen Printed Electrodes (SPEs)
2014
Oxidized Single-Wall Carbon Nanohorns (o-SWCNHs) were used, for the first time, to assemble chemically modified Screen Printed Electrodes (SPEs) selective towards the electrochemical detection of Epinephrine (Ep), in the presence of Serotonine-5-HT (S-5HT), Dopamine (DA), Nor-Epineprhine (Nor-Ep), Ascorbic Acid (AA), Acetaminophen (Ac) and Uric Acid (UA). The Ep neurotransmitter was detected by using Differential Pulse Voltammetry (DPV), in a wide linear range of concentration (2-2500 μM) with high sensitivity (55.77 A M(-1) cm(-2)), very good reproducibility (RSD% ranging from 2 to 10 for different SPEs), short response time for each measurement (only 2s) and low detection of limit (LOD=0.…
Antibacterial and antioxidant activities in Sideritis italica (Miller) Greuter et Burdet essential oils
2006
Sideritis italica (Miller) Greuter et Burdet is a widespread Lamiacea in the Mediterranean region used in traditional medicine. Essential oils were antibacterial against nine ATCC and as many clinically isolated Gram-positive and Gram-negative bacterial strains. Antibacterial activity was also found against Helicobacter pylori: a dose-dependant inhibition was shown between 5 and 25 microg/ml. The antibacterial activity of the oils was expressed as MICs (minimum inhibitory concentrations) and MBCs (minimum bactericidal concentrations). At a concentration between 3.9 and 250 microg/ml the oils showed a significant antibacterial effect against both Gram-negative and Gram-positive bacteria. In …
Ascorbic acid stability during refrigerated storage of orange–carrot juice treated by high pulsed electric field and comparison with pasteurized juice
2006
Abstract The degradation kinetics of ascorbic acid was determined in orange–carrot juice treated by PEF in order to establish its shelf life. Different electric field intensities (25, 30, 35, and 40 kV/cm) and different treatment times (from 30 to 340 μs) were studied. The ascorbic acid degradation rate (k) obtained was −0.009 ± 0.0008 μs−1, −0.0140 ± 0.0009 μs−1, −0.0220 ± 0.0023 μs−1 and −0.0187 ± 0.0049 μs−1 for fields of 25, 30, 35, and 40 kV/cm, respectively. The treatment selected was 25 kV/cm. The shelf life of the orange–carrot juice treated by pulses at 25 kV/cm for two times (280 μs and 330 μs) was compared with a heat-treated juice (98 °C, 21 s) kept in refrigerated storage at 2 …
Ascorbic acid in orange juice–milk beverage treated by high intensity pulsed electric fields and its stability during storage
2010
Abstract The degradation of ascorbic acid was determined in a ready-to-drink orange juice–milk beverage treated by high intensity pulsed electric fields (PEF). The effects of PEF treatment were compared to those of heat pasteurization (90 oC, 20 s). Four electric field strengths (15, 25, 35, 40 kV/cm) and six treatment times for each field (from 40 µs to 700 µs) were studied. Ascorbic acid degradation was adjusted to an exponential model. The obtained ascorbic acid degradation rate constants (kE) were − 0.11·10− 3 ± 0.03·10− 3 μs− 1, − 0.23·10− 3 ± 0.07·10− 3 μs− 1, − 0.42·10− 3 ± 0.09·10− 3 μs− 1 and − 0.60·10− 3 ± 0.06·10− 3 μs− 1 for field strengths of 15, 25, 35 and 40 kV/cm, respective…
ORAC and TEAC assays comparison to measure the antioxidant capacity of food products
2009
Abstract Oxygen radical antioxidant capacity (ORAC) and trolox equivalent antioxidant capacity (TEAC) assays were compared to estimate the total antioxidant capacity (TAC) of orange juice, milk, and an orange juice-milk beverage. When the TEAC method was used with this beverage, an increase in the concentration of orange juice corresponded to an increase in TAC, but increasing the percentage of milk did not increase the TAC value. When the ORAC method was applied, it was seen that increased concentrations of juice or milk corresponded to greater antioxidant capacity. An evaluation was also made of the influence of certain compounds (ascorbic acid, gallic acid, β-carotene, lutein, zeaxanthin…
The quality of orange juice
2013
Mild processing technologies allow to obtain OJ available year-round, with characteristics closer to those of fresh orange, namely for its content in substances exhibiting free radical scavenging and antioxidant activities. These healthy components, mainly vitamin C, carotenoids and flavonoids, exhibit different absorption kinetics, bioavailability and antiradical mechanisms. Anyway, there is greater absorption of these nutrients when taken not as singly as supplements, but when consumed in minimally processed fruit, such as OJ, in which they naturally appear along with all the other biologically active phytonutrients that citrus fruits contain. Type of processing, packaging and storage con…
Antioxidant therapy counteracts the disturbing effects of diamide and maternal ageing on meiotic division and chromosomal segregation in mouse oocytes
1998
This study aims (i) to ascertain whether oxidative-stress-induced disturbances in chromosomal distribution in the metaphase-II spindle of mouse oocytes can be counteracted by supplementing culture medium with antioxidants; and (ii) to determine whether supplemental intake of antioxidants neutralizes the disturbing effects of maternal ageing on segregation of chromosomes during the first meiotic division and distribution of chromosomes in the metaphase-II spindle. (i): Germinal vesicle oocytes from unstimulated 10-12 week old mice were matured in vitro in the presence or absence of diamide and/or dithiothreitol. Metaphase-II oocytes were fixed and stained with 4',6-diamidino-2-phenylindole (…
Effect of opuntia ficus-indica mucilage edible coating on quality, nutraceutical, and sensorial parameters of minimally processed cactus pear fruits
2021
Cactus pear (Opuntia ficus-indica (L.) Mill.) is a non-climacteric fruit with a relatively short postharvest life span, being very sensitive to water loss, darkening and decay. Cactus pear is a spiny fruit, and the presence of glochids limits fruit consumption and diffusion
The influence of harvest period and fruit ripeness at harvest on minimally processed cactus pears (Opuntia ficus-indica L. Mill.) stored under passiv…
2015
Abstract The aim of this study was to investigate the effect of (a) harvest season (summer and late crop), (b) fruit ripening stage at harvest and (c) time of storage, on the quality of minimal processed cactus pear ( Opuntia ficus-indica ). Fresh cut peeled cactus pears harvested at commercial harvest stage or when ripe on tree in August (summer crop) and October (late crop), were stored for 3, 5, 7 and 12 d at 5 °C and 95% RH in polyethylene terephthalate ( PET) packages under passive atmosphere conditions. Visual quality and crunchiness score, flesh color, microbiological analysis, total soluble solids (TSS), total acidity (TA), total phenolics, ascorbic acid and β-carotene contents were…