Antioxidant capacity of some caramel-containing soft drinks

Antioxidant properties of foods and beverages have been widely studied; however, few data have been reported on the antioxidant capacity of soft drinks. Apart from fruit juice-based drinks, some of the most common soft drinks contain as a colouring agent one of the four caramel colours allowed in foods (E150 d). Caramels contain melanoidin compounds, which have been reported to contribute to the antioxidant powers of some foodstuff. This study aimed to ascertain the contribution to the antioxidant activity of some caramel-containing soft drinks, such as cola drinks, and chinotto, an original Italian soft drink. Some commercial caramel colours were analysed for main parameters, i.e. HMF (5-(hydroxymethyl)-2-furfural), residual glucose and fructose content, total reducing compounds by the Folin–Ciocalteau reagent, and the antioxidant activity by the FRAP and DPPH^∗ methods. Similar analyses were performed on various soft drinks coloured with E150 d. The results showed that even if soft drinks have a lower antioxidant activity than other beverages such as tea, coffee or chocolate, they may contribute to the antioxidant pool assumed with the diet, since the antioxidant activity ranged from 0.2 for cola-like soft drinks to 1.0 mmoles Trolox equivalent/l for chinotto drinks.