PT  - JOURNAL ARTICLE
AU  - Diana Gazzola
AU  - Simone Vincenzi
AU  - Gabriella Pasini
AU  - Giovanna Lomolino
AU  - Andrea Curioni
TI  - Advantages of the KDS/BCA Method over the Bradford Assay for Protein Quantification in White Wine and Grape Juice
AID  - 10.5344/ajev.2014.14076
DP  - 2014 Dec 12
TA  - American Journal of Enology and Viticulture
PG  - ajev.2014.14076
4099  - http://www.ajevonline.org/content/early/2014/12/05/ajev.2014.14076.short
4100  - http://www.ajevonline.org/content/early/2014/12/05/ajev.2014.14076.full
AB  - The present study compared the performance of two colorimetric protein assays, the Bradford and the potassium dodecyl sulphate/bicinchoninic acid (KDS/BCA) methods, for use in wine and grape juice analysis. The Bradford assay was strongly affected by protein type, whereas the KDS/BCA method had lower protein-to-protein variation, with BSA and lysozyme revealing a response slope similar to that of wine proteins. In the Bradford assay, the presence of 12% ethanol and 200 mg/l of wine polyphenols lowered the protein response by 28 and 16%, respectively, whereas in the KDS/BCA assay, the interference was insignificant. Among 64 white wines, the correlation between protein haze potential as determined by a heat test and protein content was better for the KDS/BCA assay. This study confirms the superiority of the KDS/BCA assay over the Bradford assay for quantifying protein in white grape juice and wine, and provides better predictive value with respect to the risk of white wine protein instability.