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Antioxidant capacity of bovine milk as assayed by spectrophotometric and amperometric methods

Chen, Jun LU ; Lindmark Månsson, Helena LU ; Gorton, Lo LU and Åkesson, Björn LU (2003) In International Dairy Journal 13(12). p.927-935
Abstract
The total antioxidant capacity (TAC) of bovine milk, whey, and low-molecular-weight (LMW) fractions of whey was investigated using spectrophotometric methods including an ABTS-based method (reduction of the cation radical of 2,2′-azinobis(3-ethylenebenzothiazoline-6-sulfonic acid)) and a FRAP method (reduction of Fe3+). Significant antioxidant capacity in milk and whey was demonstrated by the ABTS method (TAC(ABTS)), and it apparently increased with increasing pH. TAC (ABTS) was several-fold higher in milk than in whey, which had a slightly higher TAC than a LMW fraction prepared from it. Also the FRAP method could be used to demonstrate TAC in whey, although the low pH necessary for this method led to some protein precipitation. Most of... (More)
The total antioxidant capacity (TAC) of bovine milk, whey, and low-molecular-weight (LMW) fractions of whey was investigated using spectrophotometric methods including an ABTS-based method (reduction of the cation radical of 2,2′-azinobis(3-ethylenebenzothiazoline-6-sulfonic acid)) and a FRAP method (reduction of Fe3+). Significant antioxidant capacity in milk and whey was demonstrated by the ABTS method (TAC(ABTS)), and it apparently increased with increasing pH. TAC (ABTS) was several-fold higher in milk than in whey, which had a slightly higher TAC than a LMW fraction prepared from it. Also the FRAP method could be used to demonstrate TAC in whey, although the low pH necessary for this method led to some protein precipitation. Most of the ferric-reducing activity of whey was found in the LMW fraction. The TAC values obtained using these methods were also compared to those obtained using a newly developed flow-injection amperometric (FIAmp) procedure for LMW fractions. High correlations were found for the TAC values of LMW samples obtained by the ABTS, FRAP and FIAmp methods (R2>0.8, P<0.001). Furthermore, to identify the major antioxidants in the LMW fraction, it was treated by uricase. Since most of the TAC (using ABTS, FRAP and FIAmp methods) was removed by uricase treatment, it could be concluded that urate is the major antioxidant in the LMW fraction. Also the effect of heat treatment on TAC in milk and whey was monitored. After heating of whey at 63°C for 1 h, TAC(ABTS) tended to increase by at least 20%, while TAC(FRAP) was not significantly changed. In milk, TAC(ABTS) remained constant during the same heat treatment. It is concluded that the methods tested gave the most reliable results for the LMW fraction of whey and that the use of several methods is necessary to characterise the antioxidant capacity of milk. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
International Dairy Journal
volume
13
issue
12
pages
927 - 935
publisher
Elsevier
external identifiers
  • wos:000186359600001
  • scopus:0242494957
ISSN
0958-6946
DOI
10.1016/S0958-6946(03)00139-0
language
English
LU publication?
yes
id
2d4a832b-fbf7-48fd-922f-2bc57c0c656b (old id 128858)
date added to LUP
2007-06-26 13:20:03
date last changed
2017-09-10 04:29:47
@article{2d4a832b-fbf7-48fd-922f-2bc57c0c656b,
  abstract     = {The total antioxidant capacity (TAC) of bovine milk, whey, and low-molecular-weight (LMW) fractions of whey was investigated using spectrophotometric methods including an ABTS-based method (reduction of the cation radical of 2,2′-azinobis(3-ethylenebenzothiazoline-6-sulfonic acid)) and a FRAP method (reduction of Fe3+). Significant antioxidant capacity in milk and whey was demonstrated by the ABTS method (TAC(ABTS)), and it apparently increased with increasing pH. TAC (ABTS) was several-fold higher in milk than in whey, which had a slightly higher TAC than a LMW fraction prepared from it. Also the FRAP method could be used to demonstrate TAC in whey, although the low pH necessary for this method led to some protein precipitation. Most of the ferric-reducing activity of whey was found in the LMW fraction. The TAC values obtained using these methods were also compared to those obtained using a newly developed flow-injection amperometric (FIAmp) procedure for LMW fractions. High correlations were found for the TAC values of LMW samples obtained by the ABTS, FRAP and FIAmp methods (R2&gt;0.8, P&lt;0.001). Furthermore, to identify the major antioxidants in the LMW fraction, it was treated by uricase. Since most of the TAC (using ABTS, FRAP and FIAmp methods) was removed by uricase treatment, it could be concluded that urate is the major antioxidant in the LMW fraction. Also the effect of heat treatment on TAC in milk and whey was monitored. After heating of whey at 63°C for 1 h, TAC(ABTS) tended to increase by at least 20%, while TAC(FRAP) was not significantly changed. In milk, TAC(ABTS) remained constant during the same heat treatment. It is concluded that the methods tested gave the most reliable results for the LMW fraction of whey and that the use of several methods is necessary to characterise the antioxidant capacity of milk.},
  author       = {Chen, Jun and Lindmark Månsson, Helena and Gorton, Lo and Åkesson, Björn},
  issn         = {0958-6946},
  language     = {eng},
  number       = {12},
  pages        = {927--935},
  publisher    = {Elsevier},
  series       = {International Dairy Journal},
  title        = {Antioxidant capacity of bovine milk as assayed by spectrophotometric and amperometric methods},
  url          = {http://dx.doi.org/10.1016/S0958-6946(03)00139-0},
  volume       = {13},
  year         = {2003},
}