Accounting for co-extractable compounds (blank correction) in spectrophotometric measurement of extractable and total-bound proanthocyanidin in Leucaena spp
Methods to account for the spectral interference of co-extractable compounds (blank correction) in the spectrophotometric analysis of both extractable and bound proanthocyanidin (PA) using the proanthocyanidin (butanol/HCl) assay were evaluated. Crude extractable and bound PA sample matrices of PA-f...
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Published in | Journal of the science of food and agriculture Vol. 82; no. 8; pp. 860 - 868 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Chichester, UK
John Wiley & Sons, Ltd
01.06.2002
Wiley |
Subjects | |
Online Access | Get full text |
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Summary: | Methods to account for the spectral interference of co-extractable compounds (blank correction) in the spectrophotometric analysis of both extractable and bound proanthocyanidin (PA) using the proanthocyanidin (butanol/HCl) assay were evaluated. Crude extractable and bound PA sample matrices of PA-free Leucaena magnifica were used. Extractable PA blanks generated in heated 95% butanol/5% H2O reagent underestimated the optical density (absorbance) of co-extractable compounds by 24% (P < 0.01), whereas unheated 95% butanol/5% HCl blanks, incubated at room temperature, accurately measured the absorbance of the background matrix (P < 0.01). Current procedures that estimate bound PA concentrations using the proanthocyanidin assay produce intensely coloured background matrices. Recovery measurements from total-bound PA extracts spiked with 1071 and 2142 µg anthocyanidin per tube indicated that existing analytical procedures that do not account for the spectral interference of co-extractable compounds overestimated (P < 0.01) bound PA concentrations by 69 and 38% respectively. An innovative technique that generated an internal correction factor for each sample, using wavelength-scanning spectrophotometry and non-linear curve-fitting computer software, was developed. This procedure recovered 100% of added anthocyanidins from bound PA matrices. |
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Bibliography: | http://dx.doi.org/10.1002/jsfa.1106 Australian Centre for International Agricultural Research (ACIAR) - No. 9433 istex:F13B3FE21985A43BAF350C274BE7B2A5E1939A0D ark:/67375/WNG-WVFSLDWQ-9 ArticleID:JSFA1106 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0022-5142 1097-0010 |
DOI: | 10.1002/jsfa.1106 |