The aim of the present study was to evaluate the effect of addition of 5% of apple peel powder (APP) and sugars (1, 5% of glucose, fructose, sucrose or trehalose) in apple purée on its phenolic composition and antioxidant activity (AOA). Apple purée samples were processed by freezing and freeze-drying. Apple purées containing APP showed higher phenolics, and AOA than the purées without APP. In freeze-dried samples the highest retention of individual polyphenols was achieved with addition of 1% of fructose or trehalose. However, in frozen samples the best impact on polyphenol retention had 5% of sucrose or trehalose. The results from this study showed the antioxidant potential of apple peel as a naturally-sourced antioxidants as well as a new insight into phenol-sugar interaction. These new findings could be of interest for the development of new food products rich in antioxidants which can improve human health.
Keywords: Antioxidant activity; Apple peel powder; Apple purée; Polyphenols; Trehalose.