EFFECT OF pH ON ANTIOXIDATIVE ACTIVITY AND OTHER CHARACTERISTICS OF CARAMELIZATION PRODUCTS

Abstract

Antioxidative activity and other characteristics of caramelization products (CPs) from fructose or glucose solutions prepared at pHs ranging from 7.0 to 12.0 with heating at 100C for various times (0–180 min) were investigated. The degradation of both sugars increased with increasing pH levels and heating time (P < 0.05). The intermediate degradation products and browning intensity also increased when pH and heating time increased (P < 0.05) as evidenced by the increase in A270, A285 and A420, respectively. The reducing power and 2–2-diphenyl-1-picrylhydrazyl radical scavenging activity of CPs were coincidental with the browning development and the intermediate formation. Generally, CPs from fructose showed greater antioxidative activity as shown by the higher reducing power and scavenging effect than CPs from glucose. Therefore, CPs from both sugars with pronounced antioxidative activity can be prepared by heating fructose or glucose solutions at very alkaline pH for an extended time.