Industrial Crops and Products 53 (2014) 274–281 Contents lists available at ScienceDirect Industrial Crops and Products journa l h om epa ge: www.elsevier.com/locate/indcrop Antioxidant properties of the anthocyanin-containing ultrasonic extract from blackberry cultivar “ ˇ Caˇ canska Bestrna” Jasna Ivanovic a,∗ , Vanja Tadic b , Suzana Dimitrijevic c , Marko Stamenic a , Slobodan Petrovic d , Irena Zizovic a a Department of Organic Chemical Technology, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia b Institute for Medicinal Plant Research “Dr Josif Panˇ ci´ c”, Tadeuˇ sa Koˇ s´ cuˇ ska 1, 11000 Belgrade, Serbia c Department of Biochemical Engineering and Biotechnology, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia d Department of Organic Chemistry, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia a r t i c l e i n f o Article history: Received 31 October 2013 Received in revised form 27 December 2013 Accepted 30 December 2013 Keywords: Rubus fruticosus Ultrasonic extraction Antioxidant activity Anthocyanins Total phenolic content Tannins a b s t r a c t For the first time, an ultrasound-assisted extraction was used to investigate isolation of anthocyanin- containing extracts from the blackberry cultivar “ ˇ Caˇ canska Bestrna” widely grown in Serbia. Sonication time and temperature influence on the yield, active substances content and antioxidant activity of the extracts isolated from blackberry fruit purée was discussed. Ultrasound-assisted extraction with acid- ified ethanol at room and moderately high temperature (40 ◦ C) enabled rapid isolation (15–30 min) of anthocyanin-containing blackberry extracts with the high yields (5.3–6.3%). Both increase of the sonica- tion temperature and time within studied ranges had positive effect on the extraction yield. The HPLC analysis revealed the presence of the anthocyanins in the investigated samples. After hydrol- ysis of all the samples, aglycone–cyanidin was detected in the samples. Determined cyanidin content in the obtained blackberry extracts (0.7–1.0%) was up to 20 times higher than in the blackberry juice. Cyanidin content was positively affected by sonication time and temperature increase. The antioxidant properties of the extracts were analyzed by the ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assays. Positive effect of increase of the sonication time and/or temperature on the scavenging activity of the extracts against free DPPH radicals and thus lower IC 50 values was demonstrated. Strong linear correlation of DPPH radical scavenging capacities of the extracts with content of cyanidin and tannins was established. FRAP values significantly correlated with total tannin content in the extracts. The analyses of composition and antioxidant properties in this study revealed great potential of black- berry ultrasonic extracts of the cultivar “ ˇ Caˇ canska Bestrna” for further use in food and pharmaceutical industries. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Blackberry (Rubus fruticosus L., Rosaceae) has been highly appreciated by consumers not just for its high nutrient value (Acosta-Montoya et al., 2010) but for its beneficial influence on the physical and mental health (Tate et al., 2003; Tavares et al., 2012). Beside a high content of nutrients such as dietary fiber, vitamin C, vitamin K, folic acid and essential minerals, blackberry crops, specifically fruits, represent a significant source of polyphenolic compounds such as ellagic acid, tannins, ellagitannins, quercetin, gallic acid, anthocyanins, and cyanidins (Elisia et al., 2007; Hager et al., 2008; Sariburun et al., 2010). ∗ Corresponding author. Tel.: +381 11 3303 709; fax: +381 11 3370 387. E-mail address: jasnai@tmf.bg.ac.rs (J. Ivanovic). The antioxidant activity of blackberry was shown to be highly correlated with anthocyanin content (Elisia et al., 2007; Jakobek et al., 2007). Anthocyanins (glycosides and acylglycosides of antho- cyanidins) are natural water-soluble pigments responsible for orange, red, purple and blue colors of fruits, vegetables and flow- ers. (Haminiuk et al., 2012; Li et al., 2012). They have been regarded as potential replacements for synthetic food colorants (E163), and they play important role in human nutrition (Haminiuk et al., 2012). A growing interest in anthocyanins is mainly due to their antioxi- dant potential and the association between their consumption and the prevention of cancer, coronary heart disease and other degen- erative disorders (Dai et al., 2007, 2009; Duchnowicz et al., 2012; Hassan and Abdel-Aziz, 2010; Tate et al., 2003). Serbia accounted for 69% of the blackberry area in Europe and it is ranked the fourth in world blackberry production after USA, Mexico and China (Strik et al., 2008). Predominant cultivars grown 0926-6690/$ – see front matter © 2014 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.indcrop.2013.12.048