Search results for "ascorbic acid"

QUALITY ATTRIBUTES, PECTOLYTIC ENZYME ACTIVITIES AND PHYSIOLOGICAL CHANGES DURING POSTHARVEST RIPENING OF NECTARINE

1996

The postharvest ripening at 20C and 90-95% RHfor 10 days of 'Armking' nectarine grown in a greenhouse was investigated over two seasons. Firmness, titratable acidity, ascorbic acid, pH and maturity index were all adequate to stablish the rate ofripening. However, soluble solids content and reducing and non-reducing sugars showed no significant changes. It took about 10 days for very early ripening fruit (100 g weight and 82 N firmness) and 6 days for normal early ripening fruits (115 g weight and 46 N firmness), both harvested at preclimacteric stage, to become eating ripe (near 20 N). Total weight loss and decay after 10 days was approximately 11%. During ripening there was a temporal coin…

Application of ultrasound as clean technology for extraction of specialized metabolites from stinging nettle (Urtica dioica L.)

2022

Nettle is a highly valued medicinal plant that is still largely neglected, both in terms of nutrition and use for pharmacological purposes. Tinctures, i.e., alcoholic extracts, are becoming increasingly popular nettle products, mainly because they allow better availability of phytochemicals and their stability over a longer period of time. The production of alcoholic extracts is a chemically demanding process that is still usually carried out using conventional techniques, which have numerous drawbacks. The use of green technologies such as ultrasound-assisted extraction (UAE), which is characterized by high efficiency of phytochemical extraction, shorter treatment time, and a much lower en…

Antioxidant properties of polyphenol-rich cocoa products industrially processed

2010

Fermentation and roasting are the main causes of polyphenol degradation during the process for obtaining cocoa products. In the present study, a process for obtaining polyphenol-rich cocoa products on an industrial scale is described. The process avoids the fermentation and roasting steps and includes a step for the inactivation of the enzyme Polyphenol Oxidase (PPO), which helps preserve the polyphenol content present in the raw cocoa bean. In addition, our study evaluates the antioxidant capacity and characterizes the flavonoid profile of the polyphenol-rich cocoa products obtained from the natural polyphenolrich cocoa cake. Using different protocols, we have obtained three cocoa extracts…

Modelling the effect of ascorbic acid, sodium metabisulphite and sodium chloride on the kinetic responses of lactic acid bacteria and yeasts in table…

2010

he goal of this work was to apply the Quasi-chemical primary model (a system of four ordinary differential equations that derives from a hypothetical four-step chemical mechanism involving an antagonistic metabolite) in the study of the evolution of yeast and lactic acid bacteria populations during the storage of Manzanilla–Aloreña table olives subjected to different mixtures of ascorbic acid, sodium metabisulphite and NaCl. Firstly, the Quasi-chemical model was applied to microbial count data to estimate the growth–decay biological parameters. The model accurately described the evolution of both populations during storage, providing detailed information on the microbial behaviour. Secondly…

Bioavailability and metabolism.

2002

Interaction of sodium, lithium, caesium, and potassium ions with ascorbyl radicals.

1987

Abstract The influence of the concentration of sodium, lithium , caesium, and potassium ions as well as of the ionic strength of the solutions used on the dismutation rate of ascorbyl radicals has been investigated. While the dismutation rate was not influenced by Li+, it decreased, however, with increasing concentrations of the other ions investigated. The largest effect was obtained with Na+. This change in dismutation rate indicates a stabilizing effect on ascorbyl radical by these ions.

Chemical-physical and nutritional characteristics of mature-green and mature-ripe ‘Kensington Pride’ mango fruit cultivated in Mediterranean area dur…

2017

Introduction - Mango is a very short postharvest life climacteric fruit. Mangoes are usually harvested firm and green because they are often assigned to long transportation before reaching the market, or they are collected after color break for local markets. In both cases, temperature control is the most critical factor in fruit ripening management. The aim of this study was to investigate the quality evolution of mature-green and mature-ripe mango fruit submitted to 8°C and 90 ± 5% of relative humidity to assess the possibility to prolong its postharvest life. Materials and methods - The fruit of mango (Mangifera indica L. cv. Kensington Pride) grown in a Mediterranean environment was s…

Prevalence and Risk Factors for Vitamin C Deficiency in North and South India: A Two Centre Population Based Study in People Aged 60 Years and Over

2011

BackgroundStudies from the UK and North America have reported vitamin C deficiency in around 1 in 5 men and 1 in 9 women in low income groups. There are few data on vitamin C deficiency in resource poor countries.ObjectivesTo investigate the prevalence of vitamin C deficiency in India.DesignWe carried out a population-based cross-sectional survey in two areas of north and south India. Randomly sampled clusters were enumerated to identify people aged 60 and over. Participants (75% response rate) were interviewed for tobacco, alcohol, cooking fuel use, 24 hour diet recall and underwent anthropometry and blood collection. Vitamin C was measured using an enzyme-based assay in plasma stabilized …

Maintenance of GSH content in primary astrocyte cultures under oxidative stress conditions.

1993

Untersuchungen über die chronische Toxizität der Ascorbinsäure bei der Ratte

1963

Bei einer chronischen Verabreichung (10 Wochen) von 6,5 g Ascorbinsaure je kg Korpergewicht per os wurden bei der Ratte keine schadlichen Wirkungen beobachtet, selbst wenn die Tiere einer Stressituation (4 Wochen dauernde eiweisarme Ernahrung) unterworfen wurden. Tagesdosen von 27,3 g/kg Korpergewicht erwiesen sich als sicher toxisch. Die Mortalitatsrate betrug bei dieser Dosierung 77% innerhalb von 4 Wochen. Auf Grund dieser Versuche kann man als oberste Grenze der Vertraglichkeit bei chronischer Zufuhr 10 g Ascorbinsaure je kg Korpergewicht annehmen. Unter Zugrundelegung dieser Zahl ergibt sich fur die als wunschenswert erachtete Tagesdosis von 75 mg fur den Menschen eine Sicherheitsspann…