engleski

Different approaches (physiological vs. chemical) to estimation of antioxidant activity of breakfast cereals

Although numerous recent articles have reported a significant antioxidant capacity of different (pseudo)cereals and derived products, breakfast cereals have rarely been evaluated as nutritive antioxidant sources. Although most of antioxidant capacity assays in the literature are significantly limited by the extraction technique, since some antioxidants may remain in the extraction residues, antioxidant activity is usually determined in methanolic or ethanolic extracts. Therefore, the aim of this study was to compare an in vitro physiological (enzymatic) procedure with methanol/water/HCl extraction procedure for extraction of antioxidants from 15 commercial breakfast cereals purchased from Croatian suppliers. Antioxidant activity of obtained extracts was determined using ferric reducing power (FRAP) method and Trolox equivalent antioxidant capacity (TEAC) method. The reducing power of corresponsive chemical and physiological extracts was about equal, but varied significantly depending of the type of breakfast cereals investigated (29.9 in cornflakes - 242.1 mmol Fe2+/100g dry matter in fruit musslie). The in vitro physiological procedure yielded significantly higher radical scavenging capacity in comparison to the chemical extraction, and varied significantly among investigated breakfast cereals (0.6 – 107.7 in chemical extracts and 24.6 – 494.5 in physiological extracts). Significant correlation coefficients were obtained between total phenolic content and investigated types of antioxidant antioxidant activities in both, physiological and chemical extracts, indicating that phenolic compounds can be considered as the principal bearers of antioxidant activity in these types of foodstuff.

breakfast cereals; antioxidant activity; polyphenols; physiological extraction

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