Review of the Determination of the Antioxidant Activity of Foods, Food Ingredients, and Dietary Supplements by Thin Layer Chromatography-Direct Bioautography, Spectrometry, and the Dot-Blot Procedure

This paper reviews a selection of the most important studies on antioxidants in foods (including beverages), food ingredients, and dietary supplements by effect-directed analysis using TLC with DPPH*, ABTS*+, and β-carotene direct bioautography. Total antioxidant activity by visible mode spectrometry (colorimetry) with TLC used offline to obtain additional analytical results, mostly for identification and quantification of phenolic compounds in samples, is also discussed. Finally, dot-blot assay for total antioxidant activity, carried out on a TLC plate without mobile-phase development, is reviewed as an alternative with possible advantages compared with spectrometry.