Cooked garlic & antioxidant activity. Correlation with organosulphur compound compositions

Abstract

The present work is a continuation of a previous paper on thesubject. It aims at studying the antioxidant mechanisms of garlic samplessubjected to different cooking treatments, and to find relationships withthe main beneficial pure organosulfur compounds (OSCs). Antioxidantactivity was tested by free radical scavenging against 2,2-diphenyl-1-picrylhydrazyl radical (DPPH*) and 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonicacid) diammonium salt (ABTS+*), Fe(III) reducingability (FRAP) and linoleic acid co-oxidation initiated by soybean lipoxygenase in a micelle system. DPPH, ABTS and FRAP assays showed thehighest activity for raw garlic samples, while β-carotene bleaching assayyielded the highest activity for stir-fried garlic. Pure OSCs tested byDPPH, FRAP and β-carotene bleaching assays showed that ajoenes andvinyldithiins were the compounds that presented the highest activity. Toour knowledge, this study is the first demonstration that home-cookedgarlic retains its antioxidant activity, and which are the mechanismsinvolved.