Kinetic and prediction studies of ascorbic acid degradation in normal and concentrate local lemon juice during storage

Kinetics of the loss of ascorbic acid (AA) in local lemon juice of 9° and 50° Brix stored at 25, 35, and 45 °C for 4 months have been investigated. The results indicate that increases of concentrations and temperatures increase the rate of AA degradation. The calculated values of activation energies...

Full description

Saved in:
Bibliographic Details
Published in:Food chemistry 2007, Vol.101 (1), p.254-259
Main Authors: Al-Zubaidy, Mazin M.I., Khalil, Rabah A.
Format: Article
Language:English
Subjects:
Ascorbic acid
brix
chemical degradation
Degradation
equations
food composition
food storage
juice concentrates
Kinetics
lemon juice
mathematical models
Prediction
reaction kinetics
shelf life
storage temperature
Thermodynamic functions
thermodynamics
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Kinetics of the loss of ascorbic acid (AA) in local lemon juice of 9° and 50° Brix stored at 25, 35, and 45 °C for 4 months have been investigated. The results indicate that increases of concentrations and temperatures increase the rate of AA degradation. The calculated values of activation energies ( E ≠) and frequency factors ( A) at different Brix imply that the concentration of juice does not change the mechanism of degradation. Thermodynamic functions of activation (Δ G ≠, Δ H ≠, Δ S ≠ and K ≠) have been determined and considered briefly. A direct equation for estimation of the shelf life of stored juice with respect to first-order losses of AA, at any specific temperature and degradation ratio, has been derived and programmed successfully.
ISSN:0308-8146
1873-7072
DOI:10.1016/j.foodchem.2006.01.024