Continuous Mass Crystallization of Vitamin C inl(+)-Ascorbic Acid−Ethanol−Water System: Size-Independent Growth Kinetic Model Approach

2011 ◽  
Vol 11 (5) ◽  
pp. 1557-1565 ◽  
Author(s):  
Bogusława Wierzbowska ◽  
Nina Hutnik ◽  
Krzysztof Piotrowski ◽  
Andrzej Matynia
Keyword(s):  
Ascorbic Acid ◽  
Kinetic Model ◽  
Vitamin C ◽  
Growth Kinetic ◽  
Water System ◽  
System Size ◽  
Continuous Mass ◽  
Mass Crystallization ◽  
Model Approach

Crystallization of vitamin C in a continuous DT MSMPR crystallizer – Size independent growth kinetic model approach

2008 ◽  
Vol 43 (4) ◽  
pp. 381-389 ◽  
Author(s):  
B. Wierzbowska ◽  
K. Piotrowski ◽  
J. Koralewska ◽  
A. Matynia ◽  
N. Hutnik ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Vitamin C ◽  
Growth Kinetic ◽  
Model Approach

Kinetic model of lipase-catalyzed conversion of ascorbic acid and oleic acid to liposoluble vitamin C ester

2013 ◽  
Vol 71 ◽  
pp. 89-96 ◽  
Author(s):  
Dejan Bezbradica ◽  
Marija Stojanović ◽  
Dušan Veličković ◽  
Aleksandra Dimitrijević ◽  
Milica Carević ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Oleic Acid ◽  
Kinetic Model ◽  
Vitamin C

Preliminary design of the activated sludge system — standard codes versus kinetic model equations

1978 ◽  
Vol 5 (1) ◽  
pp. 26-31
Author(s):  
Frederick L. Hart
Keyword(s):  
Waste Water ◽  
Kinetic Model ◽  
Biological Treatment ◽  
System Size ◽  
Aeration Tank ◽  
Domestic Waste ◽  
Design Values ◽  
Model Equations ◽  
Biological Treatment System ◽  
Model Approach

This paper discusses the origin and concepts of kinetic model equations and standard specifications used to size a biological treatment system (size of aeration tank and aeration requirements). They are shown to yield very similar calculations for a domestic type of waste water, but may yield much different values if the waste water behaves differently than domestic waste. The kinetic model approach, therefore, should be considered more flexible and superior in its ability to yield appropriate design values.

Amperometric assay of vitamin C using an ascorbate oxidase enzyme electrode

1979 ◽  
Vol 44 (11) ◽  
pp. 3395-3404 ◽  
Author(s):  
Pavel Posádka ◽  
Lumír Macholán
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Oxygen Electrode ◽  
Ascorbate Oxidase ◽  
Current Response ◽  
Reaction Conditions ◽  
Long Term Storage ◽  
Oxidase Enzyme ◽  
Optimal Reaction

An oxygen electrode of the Clark type, coated by a thin, active layer of chemically insolubilized ascorbate oxidase from squash peelings specifically detects by measuring oxygen uptake 10 to 400 μg of ascorbic acid in 3 ml of phosphate buffer. The record of current response to substrate addition lasts 1-2 min. The ascorbic acid values determined in various samples of fruit juices are in good agreement with the data obtained by titration and polarography. The suitable composition of the membrane and its lifetime and stability during long-term storage are described; optimal reaction conditions of vitamin C determination and the possibilities of interference of other compounds are also examined. Of the 35 phenols, aromatic amines and acids tested chlorogenic acid only can cause a positive error provided that the enzyme membrane has been prepared from ascorbate oxidase of high purity.

scholarly journals Degradation Kinetic Modelling of Ascorbic Acid from Orange Juice

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 55
Author(s):  
Alina Soceanu ◽  
Nicoleta Matei ◽  
Simona Dobrinas ◽  
Viorica Popescu
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Orange Juice ◽  
Storage Temperature ◽  
Kinetic Modelling ◽  
Activation Parameters ◽  
Graphical Analysis ◽  
State Theory ◽  
Activation Process ◽  
Degradation Kinetic

Vitamin C or ascorbic acid is a basic nutrient, a highly effective antioxidant, widely used as food additive. Therefore, quality control in food industry demands ascorbic acid determination methods. The purpose of this study was to determine vitamin C in natural orange juices by spectrometric and voltammetric methods. Another goal was to determine the kinetic and thermodynamics activation parameters for ascorbic acid degradation in orange juices over time and at different temperatures. It was observed that during storage, ascorbic acid concentrations in orange juices were gradually decreased with time at a rate depending on storage temperature and type of orange juice. The reaction order was determined through integrated graphical analysis where the dependences of ln ct/c0 as a function of time reveals the high values for R2, indicating that the kinetics of the degradation of AA follows first order reaction at both studied temperatures. For studied samples the loss of ascorbic acid was varied between 4.33% and 9.13%. Enthalpy variation (ΔH) and entropy variation (ΔS) of activation process were obtained from the Eyring–Polany model based on transition state theory. The values of activation energy ranged between 7289.24 kJmol−1 and 15689.54 kJmol−1.

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