Search results for "ascorbic acid"

Influence of Two Different Coating Application Methods on the Maintenance of the Nutritional Quality of Fresh-Cut Melon during Storage

2021

This study aimed at evaluating the effects of two coating application methods, spraying and dipping, on the quality of fresh-cut melons. An alginate-based coating containing both ascorbic and citric acid was applied at two concentrations (5% and 10%) with both methods on fresh-cut melon. The nutritional quality of the products was investigated during 11 days of storage at 10 °C. The suitability and adaptability of the applied coatings on the fruit were evaluated based on rheological and microstructural properties. Moisture, carotenoids, total polyphenols and ascorbic acid content were analyzed on melon samples during storage. Results showed that the coating solution applied by the dipping m…

Enzymatic, physicochemical, nutritional and phytochemical profile changes of apple (Golden Delicious L.) juice under supercritical carbon dioxide and…

2018

The impact of supercritical carbon dioxide (SCCD) (10-60 MPa/45 °C/30 min) and subsequent 10 weeks storage at 4 °C on polyphenol oxidase (PPO), peroxidase (POD) activities, phenolic profile, vitamin C, sugars, physicochemical properties of cloudy apple juices was investigated. No significant changes in sugars and total polyphenols were observed, whereas significant degradation (≈28%) of vitamin C and individual polyphenols (≈18%) was noted after SCCD treatment. After 4 weeks storage only 34% of vitamin C was retained and no vitamin C was detected after this time. Ten weeks of storage caused hydrolysis of sucrose in 15%, whereas degradation of individual polyphenols ranged from 43 to 50% dep…

RATIONALE FOR THE USE OF ANTIOXIDANT VITAMINS IN CLINICAL ORGAN TRANSPLANTATION

1996

Production of a Recombinant Catechol 2,3-Dioxygenase for the Degradation of Micropollutants

2017

Phenolic compounds such as catechol represent a particular type of micropollutant whose high stability prevents rapid decay and metabolization in the environment. We successfully cloned a catechol 2,3-dioxygenase (C2,3O) from Pseudomonas putida mt-2 and expressed it in Escherichia coli BER2566. The biomass isolated from shake-flask fermentations was used to partially purify the enzyme. The enzyme proved unstable in clarified liquid fractions (50 mM Tris buffer, pH 7.6) and lost more than 90% of its activity over 7 h at 25 °C. In the presence of 10% acetone, the process was slowed down and 30% residual activity was still present after 7 h incubation. Storage of the enzyme in clear liquid fr…

The different kinetic and mechanistic behaviors of molybdenum and tungsten in the reduction of tris(benzene-1,2-dithiolato)Mo(VI) and W(VI) complexes…

2011

The mono-electronic reduction of tris(benzene-1,2-dithiolato)Mo(VI) and W(VI) complexes (ML3: M = Mo, W; L = S2C6H2−4, S2C6H3CH2−3) to their anionic forms ML−3 by L(+)-ascorbic acid (H2A) has been studied in tetrahydrofurane (THF):water and THF:methanol by means of diode-array, stopped-flow, and mass spectrometry–electrospray ionization (MS-ESI) spectroscopy. The kinetic study in methanol demonstrates that the reaction is first order in each reactant, the electron transfer being rate limiting. This fact was assessed by the absence of a primary saline effect and by the correlation observed between the activation free enthalpy (ΔG≠) and the reduction potentials measured by cyclic voltamperome…

Plasmodium falciparumMalaria: Reduction of Endothelial Cell Apoptosis In Vitro

2005

ABSTRACTOrgan failure inPlasmodium falciparummalaria is associated with neutrophil activation and endothelial damage. This study investigates whether neutrophil-induced endothelial damage involves apoptosis and whether it can be prevented by neutralization of neutrophil secretory products. Endothelial cells from human umbilical veins were coincubated with neutrophils from healthy donors and with sera from eight patients withP. falciparummalaria, three patients withP. vivaxmalaria, and three healthy controls. Endothelial apoptosis was demonstrated by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) and annexin V staining. The rate of apoptosis of cells was …

Vitamin C as a promoter of γδ T cells

2020

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Supplementation with cactus pear (Opuntia ficus-indica) fruit decreases oxidative stress in healthy humans: a comparative study with vitamin C.

2004

Background: Cactus pear (Opuntia ficus-indica) fruit contains vitamin C and characteristic betalain pigments, the radical-scavenging properties and antioxidant activities of which have been shown in vitro. Objective: We investigated the effects of short-term supplementation with cactus pear fruit compared with vitamin C alone on total-body oxidative status in healthy humans. Design: In a randomized, crossover, double-treatment study, 18 healthy volunteers received either 250 g fresh fruit pulp or 75 mg vitamin C twice daily for 2 wk, with a 6-wk washout period between the treatments. Before (baseline) and after each treatment, 8-epiprostaglandin F2α (8-epi-PGF2α) and malondialdehyde in plas…

Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance

2008

Background Exercise practitioners often take vitamin C supplements because intense muscular contractile activity can result in oxidative stress, as indicated by altered muscle and blood glutathione concentrations and increases in protein, DNA, and lipid peroxidation. There is, however, considerable debate regarding the beneficial health effects of vitamin C supplementation. Objective This study was designed to study the effect of vitamin C on training efficiency in rats and in humans. Design The human study was double-blind and randomized. Fourteen men (27-36 y old) were trained for 8 wk. Five of the men were supplemented daily with an oral dose of 1 g vitamin C. In the animal study, 24 mal…

Nutrient intakes of children aged 1-2 years as a function of milk consumption, cows' milk or growing-up milk.

2012

AbstractObjectiveTo evaluate the nutritional adequacy of diets in early childhood as a function of milk intake, cows’ milk (CM) or growing-up milk (GUM).DesignFrom a cross-sectional food consumption survey, two groups of children aged 1–2 years were defined: Group CM fed exclusively on CM ≥ 250 ml/d and Group GUM fed on GUM ≥ 250 ml/d. Proportions of children at risk of nutrient excess or insufficiency were estimated relative to the French Recommended Daily Allowances, Estimated Average Requirements or Adequate Intakes.SettingParents participating in the survey were recruited from all regions of France by a polling organization. Distribution was adjusted to that of the French population.Sub…