ORIGINAL PAPER Microwave-Assisted Extraction of Anthocyanins from Black Currant Marc Nora Pap & Sándor Beszédes & Eva Pongrácz & Liisa Myllykoski & Miklòsnè Gábor & Ernő Gyimes & Cecília Hodúr & Riitta L. Keiski Received: 20 March 2012 / Accepted: 11 September 2012 # Springer Science+Business Media, LLC 2012 Abstract This paper reports on the process optimization study of anthocyanin extraction from black currant marc by microwave-assisted extraction (MAE) using acidic sol- vents. Maximum yields of anthocyanins were achieved at pH2 with an extraction time of 10 min with a microwave power of 700 W. The anthocyanin yields in MAE were compared with those obtained by conventional solvent ex- traction (CE) using citric or hydrochloric acids, and citric acid and water with a sulfur concentration of 50 ppm. A significant reduction of extraction time was achieved using MAE; maximum anthocyanin yield was obtained after 10 min using MAE, while using CE only after 300 min. Furthermore, the amount of solvent used halved; the mass ratio of marc to solvent was 1:40 in CE and 1:20 in MAE. Additionally, the final anthocyanin concentration in the solvent phase of MAE increased by 20 % compared to the conventional extraction with hydrochloric acid at pH2 and temperature of 80 °C. The results suggest that microwave- assisted extraction is a more efficient technique for the extraction of valuable compounds from black currant residue. Keywords Black currant marc . Anthocyanin . Extraction . Microwave-assisted extraction . Anthocyanin composition Introduction Berries are rich in health-promoting compounds such as vitamins, anthocyanins, minerals, and amino acids, which are also sensitive to heat and processing. To provide con- sumers with the maximum benefit of berries in the product, minimal processing technologies are sought. The juices of wild and cultivated berries are rich in these compounds and they can be extracted from the plant tissues into the berry juices during the pressing of the berries. However, this extraction is never complete and, therefore, valuable com- pounds remain in the pomace (Zheng and Shetty 1998). This by-product of the berry-pressing process, also called marc or press cake, is rich in health-promoting compounds. For example, the black currant marc is abundant in anthocyanins (Kapasakalidis et al. 2006), which are free radical scav- engers and potential agents against oxidative stress. Antho- cyanins are also known to work in the prevention of cardiovascular illnesses, diabetes, and cancer, and have im- pressive antibacterial, antiviral and antiallergenic effects (Stintzing and Carle 2004). Kapasakalidis et al. (2006) reported that the black currant pomace and the black currant press residue can be a poten- tial source for polyphenol extraction. The phenol level in N. Pap : L. Myllykoski : R. L. Keiski Department of Process and Environmental Engineering, Mass and Heat Transfer Process Laboratory, University of Oulu, P.O. Box 4300, 90014 Oulu, Finland S. Beszédes : C. Hodúr Department of Process Engineering, University of Szeged, Faculty of Engineering, Moszkvai krt. 5-7, 6725 Szeged, Hungary E. Pongrácz Thule Institute, NorTech Oulu, University of Oulu, P.O.Box 3700, 90014 Oulu, Finland M. Gábor : E. Gyimes Department of Food Engineering, University of Szeged, Faculty of Engineering, Moszkvai krt. 5-7, 6725 Szeged, Hungary N. Pap (*) Biotechnology and Food Research, MTT Agrifood Research Finland, 31600 Jokioinen, Finland e-mail: nora.pap@mtt.fi Food Bioprocess Technol DOI 10.1007/s11947-012-0964-9