Contents lists available at ScienceDirect Industrial Crops & Products journal homepage: www.elsevier.com/locate/indcrop Research paper Solvent selection for efficient extraction of bioactive compounds from grape pomace Diandra Pintać a, ⁎ , Tatjana Majkić a , Ljilja Torović b,c , Dejan Orčić a , Ivana Beara a , Nataša Simin a , Neda Mimica–Dukić a , Marija Lesjak a a Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia b Faculty of Medicine, University of Novi Sad, Hajduk Veljkova 3, 21000 Novi Sad, Serbia c Institute of Public Health of Vojvodina, Futoška 121, 21000 Novi Sad, Serbia ARTICLE INFO Keywords: Grape pomace Polyphenols extraction Serbian grape varieties Ursolic acid Winery by-products ABSTRACT Pomace is a winemaking by-product, rich in bioactive compounds which exert various health benefits and are used as dietary supplements, cosmetic ingredients, food colorants and preservatives. Isolation and further uti- lization of these compounds is an important issue in pomace waste management. Different industries have different requirements for specific classes of compounds and thus, selective extraction methods for isolation of these classes should be developed. In this work, the efficacy of six solvents (80% MeOH, 80% EtOH, EtOAc, acetone, acidified 50% and 80% MeOH) for the extraction of polyphenolic and triterpenoid compounds was examined. Pomaces of different grape varieties from Fruška Gora winery region in Serbia were used for ex- traction. 47 phenolics and 3 triterpenoids were analyzed by LC–MS/MS and 5 anthocyanin glucosides by LC-UV/ VIS, while contents of total phenols and flavonoids were determined spectrophotometrically in obtained ex- tracts. The most efficient solvent for each class and each compound was defined: EtOAc was the best for ob- taining an extract rich in polyphenols, acidified 50% MeOH for isolation of anthocyanins, and acetone for ursolic acid. For industries that work on a large scale and aim at the highest utilization of raw material, 80% MeOH was found to be a solvent of choice, providing the highest yield of all polyphenols. This study confirmed that pomaces from Fruška Gora vineyards are a promising source of bioactive compounds, suggesting that their utilization could be very attractive for pharmaceutical, food and cosmetic industries. 1. Introduction Grape is one of the world’s most important fruit crops, mainly due to a wide range of dietary products deriving from it, such are fresh fruit and juice, wine, raisins, jam, jelly, etc. and its high content of health- giving phytonutrients (Schieber et al., 2001). Grape is a rich source of numerous classes of natural products - carbohydrates, organic acids, vitamins and minerals, but most importantly, polyphenols (Vauzour et al., 2010). Polyphenols, such as flavonols (quercetin, kaempferol, myricetin), flavanols (catechins, epicatechins), anthocyanins (malvidin 3-O-glucoside, peonidin 3-O-glucoside, petunidin 3-O-glucoside) and stilbenes (resveratrol), are predominantly distributed in the skin, seeds, stems and leaves of grapes (Xia et al., 2010). These compounds are known for their various beneficial effects on human health, among which antioxidant (Lachman et al., 2013; Rockenbach et al., 2011), cardioprotective (Otero-Pareja et al., 2015), anti-inflammatory (Manca et al., 2016; Rodrίguez-Morgado et al., 2015), antimicrobial (Oliveira et al., 2013), antiaging (Xia et al., 2010) and anticancer (Jara-Palacios et al., 2015; Tounsi et al., 2009) activities are the most acknowledged. Besides polyphenols, triterpenoid compounds (e.g. ursolic acid) can also be present. These compounds have high potential for medical ap- plication since they possess antidiabetic, anti-inflammatory, anti- oxidant, immunomodulatory, hepatoprotective and gastroprotective properties, with ursolic acid being one of the promising substances of natural origin in cancer prevention and therapy (Grigoras et al., 2013; Strzemski et al., 2016; Woźniak et al., 2015). Thus, efficient isolation and further utilization of bioactive constituents of grape and its pro- ducts has been attracting attention in the past decade (Dai and Mumper, 2010; Oliveira et al., 2013). During winemaking, only a small part of phytochemicals is http://dx.doi.org/10.1016/j.indcrop.2017.10.038 Received 20 March 2017; Received in revised form 5 October 2017; Accepted 22 October 2017 ⁎ Corresponding author. E-mail addresses: diandra.pintac@dh.uns.ac.rs, diandra90@live.com (D. Pintać). Abbreviations: BHA, butylated hydroxyanisole; BHT, butylated hydroxytoluene; EtOAc, ethyl acetate; GAE/g fw, mg of gallic acid equivalents per gram of fresh weight; TFC, total flavonoid content; TPC, total phenolic content; QE/g fw, mg of quercetin equivalents per gram of fresh weight; de, dry extract; fw, fresh weight; 80% MeOH, 80% methanol; 80% EtOH, 80% ethanol; 50% MeOH+acid, methanol:distilled water:formic acid = 50:48.5:1.5; 80% MeOH+acid, methanol:distilled water:formic acid = 80:19:1 Industrial Crops & Products 111 (2018) 379–390 0926-6690/ © 2017 Elsevier B.V. All rights reserved. MARK