The antioxidant and antiglycation activities of selected spices and other edible plant materials and their decay in sugar-protein systems under thermal stress

Abstract

Antiglycation activities of herbs and spices, have been described in relation to their in vivo anti-diabetic or anti-aging activity at physiological temperature. Under the hypothesis that those natural antioxidants may inhibit the formation of Maillard intermediates, the behavior of several hydroalcoholic plant extracts was analyzed in sugar–protein systems. Allspice, thyme, green pepper and black pepper extracts were the most efficient inhibitors, decreasing furosine formation by 60, 45, 40 and 30%, respectively. 5-hydroxymethyl-2-furfural formation decreased in the presence of the extracts and protein glycation was inhibited by the thyme extract in advanced stages. Antiglycation activities were related to polyphenols content, to radical scavenging and to iron-reducing power. In the protein–sugar systems studied at the time in which 4000 ppm of furosine were formed, the antioxidant activity dropped between 30 and 40%. Polyphenols inhibit Maillard intermediates formation, revealing the incidence of oxidative pathways, but they are depleted as a function of time.