Total polyphenolics and anti-oxidant properties of selected dried fruits and relationships to drying conditions

The total polyphenolic (TPP) and antioxidant (AOX) levels of 41 Australian and imported dried fruits including sultanas (n = 22), Carina and Zante currants (n = 13), apricots (n = 3) and prunes (n = 3) were determined. Significant differences were observed among the sultanas, possibly due to local drying conditions, but not for other fruit types. TPP and AOX levels were positively correlated with lowest and highest levels measured for apricots and Zante currants, respectively. Specific effects of drying conditions on sultanas and Sunmuscat grapes were studied by comparing rack-drying plus emulsion (E) coating with ground-drying (+/- E). Products dried by the rack (+E) method contained 1.5- to 2-fold higher TPP and AOX levels than ground-dried fruit (+/- E). Furthermore, TPP and AOX levels remained stable for up to 5 months supporting that drying and not storage conditions, were determinant in TPP and AOX levels of dried grapes. Thus, drying conditions can affect both sensory and health-related quality attributes of grapes. (C) 2011 Elsevier Ltd. All rights reserved.